THE HEMOFLAGELLATES OF , VERMILINGUAS (ANTEATERS), AND ARMADILLOS

Jeffrey J. Shaw '

The Wellcome Parasitology Unit, Instituto Evandro Chagas, Fundação Serviços de Sáude PúbUca, 66.00 Belém, Para, Brazil

Abstract Hemoflagellates found in sloths, vermUinguas (neotropical anteaters), and armadillos are listed and their taxonomic status, vectors, distribution and importance to man are discussed. Sloths, particularly two-toed sloths Choloepus, harbor the greatest variety of hemo• and in Panamá the two-toed is the major vertebrate host of braziliensis panamensis which causes cutaneous leishmaniasis in man. In the Amazon region the common long-nosed armadillo Dasypus novemcinctus is infected with a Leishmania not yet isolated from man. Two-toed sloths appear to be the major reservoir of L. b. guyanensis in northern Pará, Brazil, and in French Guiana. In an endemic "pian-bois" region of Pará, Tamanduá anteaters are important secondary reservoirs. Ali the Leishmania of sloths, anteaters and armadillos that have been studied in sandflies are peripylarians, a type of Leishmania found in New World mammals, and it is suggested that this group may have evolved in xenarthrans. The genus Endotrypanum is intermediate between Leishmania and Trypanosoma and has retained certain features of its leishmanial ancestors in the vector, but in its vertebrate host it develops in the epimastigotic form and in rare situations the trypanomorphic form. Phlebotomine sandflies are the most probable vectors of xenarthran Leishmania and Endotrypanum. In drier, more open, áreas of Panamá, sloths are commonly infected with Trypanosoma leuwenhoeki, which may be responsible for some of the ran^e/í-like infections in man. Common long-nosed armadillos are commonly infected with T. cruzi, but Brazilian stocks of this parasite belong to a zymodeme that is only rarely found in man. Separate lines of T. cruzi may have evolved in xenarthrans and from a New World leptomonad stock. There are enormous gaps in our knowledge of xenarthran hemoflagellates but it is recommended that particular priority be given to the isolation and characterization of stocks from the numerous hosts found in different geographical regions.

Abstracto Se han enumerado los hemoflagelados que se encuentran en monos perezosos, osos hormigueros neotropicales, y armadillos y se explica su status taxonómico, presencia de vectores, distribución y importância para el hombre. Monos perezosos, particularmente el mono perezoso de dos dedos Choloepus, albergan la mayor variedad de hemoflagelados y en Panamá Choloepus es el mayor hospedero entre los vertebrados de Leishmania brasiliensis panamensis el cual es la cuasa de leishmaniasis cutânea en el hombre. Choloepus es el que Ueva la mayor cantidad de L. b. guyanensis en el norte de Pará, Brasil y en la Guyana Francesa. En una región endémica "pian bois" de Pará, los osos hormigueros Tamanduá son un importante hospedero secundário. Todas las Leishmania de monos perezosos, osos hormigueros, y armadillos que han sido estudiadas en flebótomus son peripilarios, un tipo de Leishmania que se encuentra en mamíferos dei Nuevo Mundo, y se sugiere que este grupo ha podido evolutionar en xenartranos. El género Endotripanum es intermédio entre Leishmania y Tripanosoma y ha conservado ciertas características de sus antecesores leishmanianos en el vector, sin embargo en su hospedero verte• brado se desarroUa en la forma epimastigótica y raras veces en la forma tripanomórfica. Flebótomus son los vectores mas probables de Leishmania y Endotripanum en los xenartranos. En las áreas más secas y abiertas de Panamá, los monos perezosos están infectados por Tripanosoma leuwenhoeki, el cual puede ser la causa algunas de las infecciones tipo rangeli en el hombre. Los armadillos comunes de trompa larga son usualmente infectados por T. cruzi; sin embargo las cepas brasUeiias de este parasito pertenecen a un cimodema que solo en raras ocasiones se encuentra en el hombre. Líneas separadas de T. cruzi han podido evolocionar en los xenartranos y en mar- supiales a partir de un cepa leptomonade de un insecto dei Nuevo Mundo. Hay enormes brechas en nuestro conicimiento de los hemo• flagelados de xenartranos pero se recomienda que se le dé prioridad particular al aislamiento y caracterización de cepas de los abundantes huéspeded que se encuentran en las diferentes regiones geográficas.

Resumo No presente trabalho todos os hemoflagelados de preguiças, tamanduás e tatus, são citados com suas posições taxonômicas, vetores, distribuições geográficas e suas importâncias como fontes de infecção ao homem. Preguiças, especialmente as do género Choloepus, têm o maior niimero de hemoflagelados e, no Panamá, a preguiça real é um dos principais hospedeiros de Leishmania braziliensis pana• mensis, que é responsável pela leishmaniose cutânea no homem, neste país. Na região amazônica, o tatu galinha Dasypus novemcinctus, é comuraente infectado com uma espécie de Leishmania que, por enquanto, não tem sido encontrada no homem. A preguiça real é o mais importante reservatório silvestre de L. b. guyanensis no norte do estado do Pará, Brasil e na vizinha Guiana Francesa. Nas regiões endémicas de "pian bois" do Pará, tamanduás do género Tamanduá são importantes reservatórios secundários de L. b. guyanensis. Todas as leishraanias de preguiças, tamanduás e tatus, cujo desenvolvimento em flebótomos tem sido estudado, pertencem à peripilaria, que até agora só foi encontrado em mamíferos do novo mundo. O autor sugere que essas leishmanias provavelmente evolem em xenarthros. O género Endotrypanum é intermediáro entre a Leishmania e Trypanosoma e, no vetor, seu desenvolvimento é mais parecido com Leishmania mas, na preguiça, se aproxima aos membros do género Trypanosoma quanto à sua morfologia. É bem provável que os vetores de Leishmania e Endotrypanum de xenarthros sejam flebotomíneos. Nas regiões mais secas com menos árvores do Panamá, preguiças de vários géneros são infectadas com Trypanosoma leuwenhoeki, que pode ser responsável por algumas das infecções do tipo rangeli, encontrados no homem, naquele país. Infecções por T. cruzi são frequentement encontradas no tatu galinha nas Américas, mas as cepas desse parasito no Brasil, pertencem a um zimodema que raramente infecta o homem. É possível que linhagens diferentes de T. cruzi evoluam em xenarthros e marsupials, dos flagelados ancestrais. Nosso conhecimento sobre hemoflagelados dos xenarthros é extrem• amente escasso e o autor sugere que o isolamento e caracterização de amostras de vários hospedeiros de áreas geográficas diferentes seriam uma das linhas prioritárias de pesquisa.

The modem xenarthra are ali that remains of a group reviews or illustrates a particularly important point, of mammals that appeared in the fóssil record some 60 the source is cited. million years ago during the Upper Paleocene period in North America (Herschkovitz, 1971), although the PARASITES AND THEIR HOSTS xenarthrans may have become genetically distinct as a lineage more than 80 million years ago (Sarich, 1985). The hemoflagellates are protozoa of the subphylum Ali living Xenarthra are, therefore, survivors of a mam- Sarcomastigophora (flagellar and/or pseudopodial loco- malian stock that is older than such groups as the motion); class Zoomastigophorea (no chlorophyll): , that appeared in the fóssil record some 22 order (possessing a kinetoplast): family million years later in the early Ohgocene period. Their Trypanosomatidae (parasites with one flagellum). only rivais for being the oldest mammalian group in the Members of the genera Leishmania and Trypanosoma are New World are the marsupials that go back as far as the found in sloths, anteaters, and armadillos, while flag- Cretaceous period. Unlike the marsupials, who have ellates of the genus Endotrypanum occur in sloths. living members in both Austraha and the Américas, the These three genera are ali digenetic in that their life xenarthrans are, and apparently have always been, cycle involves both an invertebrate and a vertebrate host. limited to the New World. To parasitologists such mammals represent a fascinating group, for they are Genus Leishmania Ross 1903 hosts in which typically New World parasites may have evolved and survived. Members of this genus develop as amastigotes in cells of Protozoologists are presently studying interspecific and the reticuloendothelial system of their vertebrate host intraspecifíc variations of many groups in great depth and as promastigotes and paramastigotes in the intestine and in particular those economically important protozoa of their invertebrate host. The only known vectors are such as the leishmanias and trypansomes. New bio- phlebotomine sandflies (Diptera: Psychodidae). Based chemical methods are becoming available (see reviews by on their development in sandflies, Lainson and Shaw Newton and Burnett, 1972; Chance, 1979; Godfrey, (1979) divided the genus into the sections Hypopylaria, 1979) and such techniques in conjunction with studies Peripylaria and Suprapylaria. Until now the Leishmania on morphology, physiology and immunology and in vivo found in xenarthra ali belong to the section Peripylaria and in vitro behavior show a considerable degree of and no members of this section have so far been found diversity, even among organisms that are morpho- in mammals outside the neotropics. logically very similar. Godfrey (1979) drew attention to the stability that certain isoenzymes showed in different Leishmania braziliensis guyanensis Floch 1954 trypanosomatid stocks and felt that it is the insect vectors that are primarily responsible for the main- Choloepus didactylus French Guiana, Brazil (Gentile et tenance of the stable groups. al., 1981; Lainson et al., 1981b); Tamanduá tetradactyla In this article I discuss recent advances in the study of Brazil (Lainson et al., 1981a, 1981b). hemoflagellates found in xenarthra and relate those In the Monte Dourado region of Pará, Brazil infections studies to possible future lines of research. In the space of L. b. guyanensis were found in 27 of 59 two-toed available it is impossible to describe each parasite in sloths. Of these, 25 isolates were from víscera (liver and detail and to cite the authors responsible for the various spleen), 1 was from viscera and skin and the other was records in the different countries, as given in reviews by from skin only (Lainson et al., 1981b). These sloths are Shaw (1969), Hoare (1972), and Lainson and Shaw important reservoirs of L. b. guyanensis in French (1979). For convenience, each parasite is listed separa- Guiana, where 7 of 15 have been found infected (Gentile tely with its known hosts and geographical distribution. et al., 1981). If the record was pubUshed after the above-mentioned Infections of L. b. guyanensis have also been found in 6

280 Jeffrey J. Shaw of 27 Tamanduá tetradactyla anteaters captured in the Leishmania braziliensis suhspecies same region as the infected sloths (Lainson et al., 1981a, 1981b). The stocks from T. tetradactyla were biol- Choloepus didactylus Brazil. ogically and biochemically the same as those isolated A leishmania was first seen in a two-toed sloth from from man, sandflies { (Nyssomyia) umbratalis Amazónia in 1948 by Professor Leonidas Deane. The and L. (N.J whitmanij and two-toed sloths from the parasites were in stained impression smears of liver of same area. No leishmanial infections were observed in 21 sloths, captured in the Abaetetuba region of Pará, Brazil. T. tetradactyla captured in nonendemic "pian-bois" These sloths were also infected with Endotrypanum. At áreas of Pará, south of the Amazon River (Lainson et al., the time he was not sure whether the amastigotes were a 1979a). leishmanial parasite or if they were a developmental phase of Endotrypanum. More recently we isolated Leishmania braziliensis panamensis Lainson and Shaw Leishmania from the skin and viscera of two-toed sloths 1972 and there were abundant amastigotes in smears from the viscera of some of the positive animais. This is apparent• Bradypus veriegatus Costa Rica (Zeledon et al, 1975a), ly very different from infections of L. b. panamensis Panamá; Choloepus hoffmanni Costa Rica (Zeledon et in C. hoffmanni. Stocks of Leishmania from C. al., 1975a), Panamá. didactylus are presently being studied and from its This subspecies of L. braziliensis has been extensively behavior in experimentally infected sandflies L. longi- studied at the Gorgas Memorial Laboratory in Panamá palpis and hamsters and from its morphology it is clearly for some 25 years. In man it produces cutaneous lesions closely related to L. b. guyanensis. and is contracted by people who live or work in áreas where there is mature forest. Many infected species of Leishmania herreri Zeledon, Ponce and Murillo 1979 mammals and sandflies have been found but the major reservoir/vector cycle seems to involve two-toed sloths Choloepus hoffmanni Costa Rica; Bradypus veriegatus and the sandfly L. (N.j trapidoi, although four other Costa Rica. species have been indicated as possible vectors This species was described from infections found in 3 (Christensen and Herrer, 1973). The extensive survey of of 86 three-toed sloths and 7 of 63 two-toed sloths. The Panamanian mammals by Drs. Aristides Herrer and positive three-toed sloths were ali infected with Endo• Howard Christensen from 1965 to 1972 revealed in• trypanum and two were also infected with T. leuwen• fections of L. b. panamensis in 67 of 396 two-toed hoeki. One infection in a two-toed sloth was a pure one sloths, but in only 2 of 163 three-toed sloths. The of L. herreri while the others were mixed with Endo• incidence of infection in two-toed sloths from Achiote trypanum, T. leuwenhoeki and L. braziliensis. L. herreri was 37.1 percent and in those from Aguacate 26.1 was isolated from the spleen and blood of three-toed percent. In both áreas mature forest was the dominant sloths and from the skin, blood, liver and spleen of vegetation. However, in two-toed sloths captured in La two-toed sloths. Chorrera, where there was mostly secondary forest, the Unlike L. b. panamensis this species does not produce a infection rate was only 4.7 percent visible lesion in hamsters and is differentiated from No mention is made of amastigotes in smears from Endotrypanum by its growth as amastigotes in hamster sloths that were infected with L. b. panamensis and the cells grown in tissue culture. It has been isolated from sloths were ali in good health. Herrer and Telford (1969) wild-caught sandflies L. (N.j trapidoi, L. (N.)ylephiletor noted that in 8 of 13 infections, parasites appeared to be and L. shannoni, which must ali be considered as limited to the skin while in other animais they occurred potential vectors. In the original description of L. only in the viscera or in both the viscera and skin. In herreri it was stated that it had distinct nuclear and three-toed sloths from Costa Rica, one isolate was kinetoplast DNA buoyant densities and that the electro- from liver and another was from skin. In two-toed sloths phoretic mobilities of its glucosphosphate isomerase one isolate was from blood and the other from liver (GPI) and 6-phosphogluconate dehydrogenase (6-PGDH) (Zeledon et al., 1979). In the absence of Information on were different from other species of Leishmania. No the course of natural or experimental infections it is very details of these differences were given in the original difficult to interpret the presence of parasites in paper and it is hoped that this most important Infor• different tissues. Possibly animais in which parasites mation will soon become available. The presence of were found in the viscera were in the acute phase while sphaeromastigotes in smears from the skin of inoculated those in which they were limited to the skin were in the hamsters is more typical of the genus Trypanosoma chronic phase of the infection. than Leishmania. Some of the promastigote stocks isolated from Pana• manian sloths and sandflies by other workers which failed to infect hamsters might have been L. herreri.

Hemoflagelates of Xenarthrans 281 However, care must be taken in the use of infectivity (Herrer and Telford, 1969), and 39 of 72 two-toed to hamsters as a taxonomic criteria, especially if the sloths (Christensen and Herrer, 1979). Fifty percent of s stocks in question have been passaged many times. Both the two-toed sloths captured in forested áreas were \ L. mexicana and L. braziliensis lose their infectivity to positive for E. schaudinni while the infection rate was hamsters if kept in culture for long periods. Some only 3 percent in those captured in more open áreas. subspecies of L. braziliensis may lose their infectivity In sloths from Brazil, the following infection rates have after only three or four subpassages. been found: 23 of 45 two-toed sloths and O of 51 three- toed sloths (Deane, 1961; Deane and Damasceno, 1961) Leishmania species (not yet described) and 27 of 33 two-toed sloths and 1 of 21 three-toed sloths (Shaw and Lainson, unpublished). The above Dasypus novemcinctus Brazil (Lainson et al., 1979b) records refer to animais that were caught in the munic- Stocks isolated from common long-nosed armadillos ipalities of Abaetetuba, Ananindeua, Belém, Breves, captured on both the northern and southern sides of the Maracanã , Moju and Ponte de Pedras of Pará state. Amazon River are being studied at the Evandro Chagas Infections of E. schaudinni have also been found in 33 Institute. During 1978, cultures were made from 14 of 59 two-toed sloths from the Monte Dourado region of common long-nosed armadillos and promastigotes were Pará. Of these 16 were mixed infections of L. b. guyan• isolated from the blood, liver, and spleen of one, from ensis and Endotrypanum (Shaw and Lainson, unpub• the blood and liver of another, and from the spleen of a lished). As in Panamá the positive animais were asso- third. AU three isolates grew luxuriantly in culture but ciated with undisturbed "terra firme" forest. when inoculated intradermally into hamsters none pro- The first recorded infection of E. schaudinni in Costa duced visible lesions. In smears made from the inocu- Rica was in a three-toed sloth captured in Cartago lation sites a few days later we found a few intracellular Province. Subsequent records (Zeledon et al, 1979) do amastigotes. Laboratory-reared sandflies, L. longipalpis, not mention the morphology of the bloodstream forms. were fed promastigotes of the various stocks and they It is possible that the two-toed and three-toed sloths developed as typical peripylarians. Since 1979 (Lainson from the provinces of Cartago and Limón were infected et al, 1979b) we have isolated more stocks from with E. schaudinni while the infections in those from armadillos and preliminary observations suggest some San José Province could have been either E. schaudinni degree of heterogeneity among the leishmanial stocks or E. monterogeii. In ali, Endotrypanum was found in 7 from D. novemcinctus. None of the Leishmania so far of 86 three-toed sloths and 23 of 63 two-toed sloths as found in man appear to be similar to that from well as in the wild-caught sandflies i. (N.) trapidoi, L. armadillos. (N.j ylephilator and L. shannoni. In some of these The vector of the leishmanial parasite found in com• sandflies the Endotrypanum infections were mixed with mon long-nosed armadillos in Brazil is unknown. The L. braziliensis and L. herreri. apparent absence of infections of this parasite in man In forested áreas of Panamá, where E. schaudinni is could be either because it is not infective to man or common, 96 percent of the hematophagous because the vector rarely or never bites him. feeding on two-toed sloths were phlebotomine sandflies. Dissections of wild-caught and laboratory-reared sand• Genus Endotrypanum Mesnil and Brimont 1908. flies that had fed on two-toed sloths infected with E. schaudinni showed that this parasite could develop in Parasites of this genus develop as intraerythrocytic these insects. My efforts and those of other workers to epimastigotes in sloths and as promastigotes in cultures infect a range of haemotophagous insects including and sandflies. The uniqueness of members of this genus mosquitoes and reduviids were completely unsuccesful. is that they are the only trypanosomatids that parasitize These negative results in conjunction with the epi- red blood cells, a habitat that has been so successfuUy zootiological data and the fact that sandflies supported exploited by the hemosporidia. the development of E. schaudinni led me to suggest that sandflies could be the natural vector of Endotrypanum Endotrypanum schaudinni Mesnil and Brimont 1908 (Shaw, 1964). Christensen and Herrer (1976) fed 1665 laboratory-reared sandflies on wild-caught sloths and Choloepus didactylus French Guiana, Brazil; C. hoff• they considered that 136 infections had been derived manni Panamá; Bradypus veriagatus Panamá (Herrer from sloths with pure E. schaudinni infections. In most and Telford, 1969) Costa Rica; B. tridactylus Brazil flies the parasite developed as rounded or oval forms (Shaw, Lainson and Miles, unpublished). that were attached to various regions of the hind gut, The foUowing infection rates of E. schaudinni have distributed in the gut as foUows: 14 percent in the been recorded in sloths from Panamá: 37 of 110 two- cárdia, 52 percent in the midgut, 63 percent in the toed sloths and O of 39 three-toed sloths (Shaw, 1969), malpighian tubules, 60 percent in the ileum and 29 10 of 85 two-toed sloths and 1 of 77 three-toed sloths percent in the rectal ampuUa. In paired feedings they

Jeffrey J. Shaw noted that significantly more L. gomezi sandflies (70 of pyloric and ileal regions of the sandflies L.furcata and 97) were infected than L. sanguinarius sandflies (29 of L. flaviscutellata. in the former species the tips of the 168). Christensen and Herrer (1979) again noted that L. malpighian tubules were sometimes so heavily par- sanguinarius sandflies were less susceptable to infection asitized that they became enlarged. The signifícance of with E. schaudinni than L. gomezi. Christensen and infections in malpighian tubules is obscure, but it could Herrer (1976) supported my hypothesis of sandflies merely be an aberrant development in an abnormal host. being the vector of Endotrypanum and their obser• When fed on the same sloth significantly more L. vations of infections in the foregut suggests that trans- flaviscutellata sandflies became infected than L. longi• mission is by bite and not, as I had suggested, by fecal palpis sandflies. - ' , contamination. Electronmicrographs of infected sloth red cells showed Endotrypanum monterogeii Shsíw 1969 that E. schaudinni is actually inside the erythrocyte and not merely adhered to its surface. Its basic cellular Choloepus hoffmarmi Costa Rica. structure was similar to that of other trypanosomatids This species of Endotrypanum is differentiated from E. but in its posterior end there were numerous round to schaudinni by the trypanomorphic morphology of the ovoid electron translucent granules and a few irregularly intraerythrocytic form and serologically by the shaped electron dense granules (Shaw and , 1969). Nogouchi-Adler test performed on the culture forms. The former appear to coincide with basophilic inclusions This species has only been found in sloths from the seen in Giemsa stained preparations. Croft et al., (1979, temperate forests of the Tablazo Mountains of San José 1980) noted clusters of discrete particles in the cyto- province. Nothing is known of the vectors. plasm of the culture forms of certain Endotrypanum stocks. These granules were smaller than those seen by Genus rrvpanoso/wa Gruby 1843. Shaw and Bird (1969) in the bloodstream forms and had translucent centers and electron dense walls that were 14 Flagellates of this genus occur as trypomastigotes in the to 18 nm thick. Croft and his coUeagues noted that the blood of their vertebrate host and predominantly as stocks that had granules had different kinetoplast DNA epimastigotes in their invertebrate host. The infective buoyant densities and different malate dehydrogenase stage in the vector is considered to be the small meta- (MDH) and isocitrate dehydrogenase (ICDH) electro- trypomastigotes. Trypanosomes of the subgenera Herpe• phoretic mobilities from the stocks without granules. A tosoma Dolfein, \9Q\, Megatrypanum Hoare, 1964 and possible interpretation of these observations could be a Schizotrypanum Chagas, 1909 have been recorded in basic difference between Central and South American xenarthra. The relevant literature is extensive and the stocks. This would not seem to be the case, however, interested reader is referred to Hoare (1972) and reviews since a stock from a two-toed sloth from Panamá fell on the biology of T. (H.j rangeli (D'Alessandro, 1976) into the same group as two Brazilian stocks (Croft et al., and heterogeneity within the subgenus Schizotrypanum 1980). Preliminary studies in Brazil, using 14 different (Miles, 1979). enzymes, have, however, revealed clear differences between Central and South American stocks of Endo• Trypanosoma (Herpetosoma) rangeli Tejera 1920 trypanum (Shaw, Lainson Povoa and Miles , unpubl• ished). There also appears to be a lesser degree of region• Tamanduá mexicana Panamá. al heterogeneity for certain enzymes. For instance, This trypanosome was described from the reduviid bug among 16 stocks isolated from sloths captured in the prolixus of Venezuela and was first found in a lower Amazon region of Brazil, we identified 8 zymo- vertebrate host, man, some years later. This is the only demes that were only different from each other in a few member of the subgenus that invades the hemolymph enzymes. Mannosephosphate isomerase (MPI) was the and salivary glands. Transmission is by bite and not most variable and the range of forms was reminiscent of fecal contamination (Rey-Matiz, 1941). Since that date those associated with a monomeric enzyme with 3 any T. /ewzsz-like trypanosome that invades the salivary alleles. glands of reduviids is generally considered to be T. The blood forms but not the culture forms of E. rangeli. schaudinni were infective to laboratory-reared sandflies The trypanosomes found in Tamanduá from Panamá (Shaw, 1981). The flagellates that developed in the fly (Walton and Sousa, 1967), identified as T. rangeli, grew from the blood forms were morphologically similar to well in blood-agar-base (Difco) media made up with 20 those seen in culture. It appears that the infectivity in percent rabbit blood but poorly in the same base made culture is lost very rapidly because even first subpassages up with sheep or human blood. The culture forms were of an original isolate failed to infect sandflies. There infective to mice and gave rise to trypanosomes that were significantly more infections of the malphighian were said to be the same as T. rangeli. They were re- tubules and rectal tube and significantly fewer of the ported to develop in bugs as T. rangeli but the species of

Hemoflagelates of Xenarthrans 283 bug is not given nor are any details about the devel• a parasite of this reduviid, and a trypanosome that will opment. I think that these infections should be referred not develop in the original host cannot be the same. to as T. rangeli-like and perhaps more correctly as an Thus I cannot accept the use of the name T. rangeli for unidentified Herpetosoma species. . , parasites that will not develop in the bug Rhodnius prolixus, be they isolated from sloths or any other Trypanosoma (Herpetosoma) myrmecophagae Floch and mammal. Workers in the field of Chagas' disease have, in Abonnenc 1948 general, been a little more prudent and often refer to the presence of a T. crazz-like trypanosome in a given wild Myrmecophaga tridactyla French Guiana. mammal. This trypanosome of the giant anteater develops in the Christensen and Herrer (1979) successfuUy transmitted reduviid bug Rhodnius prolixus and because of this T. leuwenhoeki to guinea pigs by the bite of the reduviid some workers consider it to be a synonym of T. rangeli. bug Rhodnius pallescens that had been innoculated The bloodstream trypomastigotes are larger than those intracoelomically with culture forms, strongly suggesting of T. rangeli and until we know more about the biology that a reduviid could be the natural vector. and biochemistry of the trypanosomatids of giant Trypanosoma rangeli was recorded from 3 of 63 anteaters, the name T. myrmecophagae must be re• two-toed sloths and 4 of 86 three-toed sloths by Zeledon tained. et al. (1979), but I think that these infections in sloths from Costa Rica could also be considered as being T. leuwenhoeki.

Trypanosoma (Herpetosoma) mesnilbrimonti Deane Trypanosoma (Herpetosoma) preguici Shaw 1969 1961 Choloepus hoffmanni Costa Rica, Panamá; Bradypus Choloepus didactylus French Guiana, Brazil. veriegatus Costa Rica I recently compared stained preparations of T. While Hoare (1972) put this species into the subgenus mesnilbrimonti and T. preguici which confirm that the Herpetosoma, I have difficulties in assigning this species two species are morphologically distinct. In Brazil, to a subgenus. Its large vacuole in the nuclear region and Deane found 2 of 25 two-toed sloths were infected, its general morphology are similar to some species of one from the Utinga forest near Belém and the other Megatrypanum, such as T. megadermae, and some of the from Pirituba near Abaetetuba. Trypomastigotes of T. more primitive trypanosomes found in and . mesnilbrimonti are more numerous in the blood than T. preguici infections in both species of sloths have been those of T. preguici, are smaller than those of the associated with E. schaudinni. latter species and the position of the nucleus is similar to that of T. legeri. T. mesnilbrimonti has only been found Trypanosoma (Megatrypanum) legeri Mesnil and in sloths that are also infected wixh Endotrypanum. The Brimont 1910 vector is unknown and no development has been asso• ciated with this species in either insects or culture. Tamanduá tetradactyla Venezuela, French Guiana ,Bra• zil; T. mexicana Belize, Panamá. Trypanosoma (Herpetosoma) leuwenhoeki Shaw 1969 From the recorded infection rates it would seem that T. legeri is quite common in Tamanduá anteaters of both Choloepus hoffmanni Panamá, Costa Rica (Zeledon et species: T. tetradactyla, BrazU 5 of 20 (Deane, 1961). T. al., 1975b); Bradypus variegatus Panamá, Costa Rica mexicana Belize 5 of 12 (Lainson, 1965), Panamá 5 of (Zeledon et al, 1975b) 17 (Walton and Sousa, 1967). In these reports, no This trypanosome was isolated from the blood of 12 of mention is made of the sex or age of the positive animais 39 three-toed sloths and 17 of 110 two-toed sloths. Of nor are detaUs given of the capture sites. Deane (1961) these 29 infections, 25 were in animais that had come described both short and long forms, whose average from áreas of predominantly secondary forest and the lengths were 31.6 and 41.1 ^m, which he considered as other 4, represented by two of each species of sloth, aU being T. legeri. Only one basic morphological type were captured in an area where the predominant veg• was observed by Lainson (1965) in animais from Belize, etation was mature forest with clearings of secondary it was similar to the smaller trypomastigotes described growth. More recent records (Christensen and Herrer, by Deane. Walton and Sousa (1967), however, noted 1979) refer to infections of T. rangeli in 15 of 72 that in the trypanosomal infections of T. mexicana from two-toed sloths from Panamá. Panamá there were smaller broad forms measuring 31.5 One of the major reasons for naming T. leuwenhoeki iim and longer thin forms measuring 41.8 ^m. Because was that it would not develop in the reduviid bug of the behavior of the culture forms isolated from these Rhodnius prolixus. T. rangeli was originally described as infections, they considered that the longer thinnef trypa-

284 Jeffrey J. Shaw mastigotes were T. rangeli and the smaller shorter ones in the lower Amazon region (Deane, 1961; Lainson et were T. legeri. On morphological grounds this separation al., 1979). T. cruzi has been seen in 3 of 31 T. mexicana into two species is not fuUy justified as there was no anteaters from Panamá (Pipkin, 1968; Walton and Sousa, clear separation between the two types. 1967) but none were observed in 41 T. tetradactyla Because trypomastigotes seen in blood films and from the lower Amazon region (Deane, 1961 ;Lainson et cultures are positive does not necessarily mean that the al., 1979). Rodrigues and Mello (1942) recorded infec• culture forms belong to the trypomastigotes seen in the tions of T. cruzi in 3 of 12 r. tetradactyla that had been blood. In 29 infections in sloths from Panamá, I only captured in the forests near Belém, Brazil. Parasites were saw trypanosomes in the blood of two animais. Thus it seen in the blood of the animais and in reduviids that seems possible that Walton and Sousa (1967) could have had fed on them, but these authors gave no details of the cultured an occult trypanosome that was mixed with morphology of the bloodstream trypomastigotes or the typical T. legeri. The only published results on the flagellates from the bugs. The low infection rates in cultivation of T. legeri are those of Walton and Sousa sloths and anteaters suggest that they are accidental (1967), who noted that it grew poorly in blood-agar base hosts and not the reservoirs. In Panamá there may be (Difco) and that it could only be maintained in ecological niches (forest canopy) in which the vector(s) Senekjie's médium containing 30 percent rabbit blood; come into sporadic contact with both sloths and ant• even then it grew poorly. We have isolated what we eaters but that no such contact occurs in the lower consider to be T. legeri in nutrient agar médium (Oxoid Amazon region of Brazil. The species of bugs involved CM3) made up with 20 percent rabbit blood (Shaw and and the type of T. cruzi are not known. Lainson, unpubhshed). Initial isolates grew poorly, but Of ali the xenarthra perhaps only the common long- stocks were successfuUy maintained in this médium nosed armadillo, D. novemcinctus, can be considered as although growth has never been luxuriant. The vector of a reservoir of T. cruzi. Chagas (1912) recorded an this species is unknown. infection rate of 45 percent in common long-nosed armadillos from Minas Gerais while Freitas' (1950) Trypanosoma (Schizotrypanum) cruzi Chagas 1909 examinations of specimens of this species from São Paulo were negative. In Pará, Deane (1961) found T. Choloepus hoffmanni Panamá; Bradypus variegatus cruzi in 6 of 22 D. novemcinctus, while we also observed Panamá. infections in 6 of 22 (Lainson et al., 1979a). Barretto Tamanduá tetradactyla Brazil, Venezuela; T. mexicana and Ribeiro (1979) quote infection rates of 16 percent Panamá; Cyclopes didactylus Brazil (Miles et al., 1981). in D. novemcinctus from Argentina, 5.6 percent from Cabassous centralis Panamá; C. unicinctus Venezuela, French Guiana, 55.3 percent from Venezuela, and 5.6 French Guiana, Brazil, Argentina; Chaetophractus percent from Costa Rica. In Panamá, Clark and Dunn vellerosus Argentina; Dasypus novemcinctus United (1932) noted that 6 of 25 common long-nosed arma• States, México, Guatemala, Costa Rica, Colômbia, dillos were infected with T. cruzi, while in a survey Venezuela, French Guiana, Brazil, Argentina;/), kapleri performed in Panamá by the Gorgas Memorial Lab• Venezuela, Colômbia; Euphractus sexcinctus Brazil, oratory in 1965, only one infection was found in 58 Venezuela; Tolypeutes matacus Argentina; Zaedyus animais, Pipkin (1968) failed to find infections in 43 pichyii Argentina. common long-nosed armadillos from Panamá. Infections of T. cruzi have been recorded from many How can the very different infection rates at different species of xenarthrans. For many years workers in the times in the same countries (e.g., Brazil and Panamá) be field of Chagas' disease have suspected heterogeneity explained? Either some ecological change resulted in among the morphologically similar organisms that are different infection rates among armadillos or the disease identified as T. cruzi. However, studies on isoenzymes was present but not detected for technical reasons. In show differences that strongly suggest a number of Brazil, some 35 years passed between the positive and distinct groups (Miles, 1979). Three zymodemes (ZI, ZII negative observations. During this time, tremendous and ZIII) have been associated with the acute disease in modifications in the habitat almost certainly took place man (Miles et al., 1978, 1979) and more will undoubt- and the vector may have died out while the armadillos edly be identified. were able to adapt to the new conditions. The major Infections of T. cruzi are uncommon in two-toed sloths factor, however, is perhaps variations in the methods of and anteaters. In Panamá, I found no infections in 149 examination. Chagas (1912) detected infections by sloths, Christensen and Herrer (1979) found only one seeing parasites in stained blood smears while Freitas infection in 72 two-toed sloths and Pipkin (1968) (1950) used xenodiagnosis. In Panamá Clark and Dunn recorded one infection from 7 three-toed sloths. Zeledon (1932) found trypanosomes in stained material while the et al. (1979) did not find T. cruzi in 86 three-toed and subsequent workers used culture techniques to detect 63 two-toed sloths captured in Costa Rica. No infections infections. The methods used in the later studies per• of T. cruzi were found in 129 Brazilian sloths captured formed in both Brazil and Panamá were therefore not

Hemoflagelates of Xenarthrans 285 strictly comparable although one would suspect that Attempts are being made to identify the silky anteater both xenodiagnosis and cultures would be the more stock. sensitive techniques, with infections less likely to be detected by direct searches for parasites in the blood. THE RELATIONSHIP OF INFECTIONS TO HOST Our experience (Lainson et al., 1980) with stocks of T. BEHAVIOR AND HABITAT cruzi from common long-nosed armadillos is relevant to the possibiUty that infections were not detected because If a vector has a narrower habitat preference than the of technical problems. We found that these stocks vertebrate host there will obviously be uninfected developed very slowly in culture, taking a long time populations of the host. In addition, host behavior can to show positive test results. On occasion, cultures facilitate vector-host contact which could increase the remained negative even though bloodstream trypo• infection rate in two equally susceptable hosts that live mastigotes were seen. The armadillo stocks developed in the same area. For instance, if two mammals live in poorly in the reduviid bugs Tritoma infestans, T. brasil• the same place but one is herbivorous and the other iensis, T. sórdida, Rhodnius prolixus and insectivorous, then the latter will stand a greater chance maximus. Our recent awareness that such stocks belong of being infected with a parasite whose infective stages to zymodeme III (Miles et al., 1981) helps explain occur in the insect's feces. Other factors, such as daily difficulties in handling stocks of T. cruzi from arma• range of movement, home range size, and seasonal dillos. It also suggests that failures to detect infec• migration, can also influence the degree of vector- tion could arise from unsuitable bugs being used, the use reservior contact. The end product of these fascinating of inappropriate culture media, or because cultures were complex relationships is often mixed hemoflagellate examined too early. Clearly in the light of the recent infections. observations on the biology of isolates of T. cruzi Infection rates of T. leuwenhoeki are almost equal in from armadillos, more work is needed in áreas where both species of sloths in Panamá, while the incidence of these animais were found to be negative. E. schaudinni is high in two-toed sloths and very low in In the text books of tropical medicine and parasitology three-toed sloths. Mixed infections of T. leuwenhoeki (cf Wilcocks and Manson-Bahr, 1977), common long- and E. schaudinni are rare but concommitant infections nosed armadillos are the classical reservoir of Chagas' of L. b. panamensis and E. schaudinni are quite common disease, ahnost certainly because they were the first wild although there are more infections of the latter. This animais to be found infected with a trypanosome that mosaic of infections has been interpreted as reflecting a was morphologically similar to the one found in man. wider habitat range of the two-toed sloth as compared to Further observations are needed on infections in arma• the three-toed sloth (Shaw, 1969). While two-toed and dillos from other regions of Brazil and the Américas, three-toed sloths live in microsympatry, using the same especially the Identification of the parasites from the trees on occasion (Montgomery and Sunquist, 1978), different áreas. Chagas noted that Panstrongylus gen- two-toed sloths have larger home range spaces, and range iculatus was associated with common long-nosed arma• more widely during each night's activity (Sunquist and dillos and suggested them as the most probable vector Montgomery, 1973). among armadillos. This idea was supported by the The pattern of mixed infections in sloths from Costa observations of Barrett et al. (1980), who noted that in Rica is different from those seen in sloths from Panamá. Bahia, Brazil, a stock from an armadillo and one from a The incidence of L. b. panamensis appears to be more or reduviid bug P. geniculatus, found in an armadillo's less equal in both species of sloth yet there are far more burrow were both zymodeme III. infections of Endotrypanum in two-toed than in three- toed sloths. T. leuwenhoeki is uncommon in both Unidentified rrypanoso/na species species but when found, it is in association with either Endotrypanum or a Leishmania species (Zeledon et Cyclopes didactylus Brazil (Miles, personal commun- al.,1979). It would appear that in Costa Rica, unlike ication). Panamá, both species of sloth have equal contact with This is only the second record of a trypanosomatid the habitat of the vector of both L. braziliensis and T. from the silky anteater. The infection was detected by leuwenhoeki, but that the two-toed sloth has a greater hemoculture and growth was luxuriant. No parasites degree of contact with the vectors of Endotrypanum. were seen in stained blood smears from the positive In Brazil the relationship of infections of Endotry• . Many silky anteaters have been examined by panum and Leishmania are more similar to those seen in hemoculture but none were found infected (Lainson et sloths from Panamá. There are proportionally more al., 1979). Since the found by Miles grows infections of E. schaudinni than L. braziliensis but to luxuriantly in culture and he only found a single in• date no counterpart to T. leuwenhoeki has been found fected animal, it seems possible that it was an accidental in either species of sloth from the lower Amazon region. infection of a trypanosome of another mammal. There is no satisfactory explanation for the absence of

286 Jeffrey J. Shaw T. rangeli-like trypanosomes in armadillos from Panamá, portant secondary vector in certain situations because it especially when both sloths and anteaters have been also occurs on treé trunks. There is increasing evidence found to be infected with trypanosomes of this to support the hypothesis that sandflies are the vectors complex. It could either be that they are not susceptable of Endotrypanum. No species has been singled out as the or that there is some ecological barrier between them vector, but recent studies on the susceptability of a and a suitable vector. limited number of sandfly species to infection indicates The differences among relative infection rates of T. that only one is likely to be the major vector in a given cruzi in sloths, anteaters, and armadillos is probably area. This view is supported by the epizootiological related to differences in both the habits and habitats of observations that suggest that different sandflies are these animais. Sloths are vegetarians, predominantly responsible for the transmission of L. b. panamensis and arboreal, and do not live in any form of hoie or burrow: E. schaudinni. There have been no attempts to ex• their chances of ingesting a bug contaminated with T. perimentally transmit Endotrypanum. cruzi or of being in close contact with a vector species Experimental transmissions of Leishmania by the bite are slight. Tamanduá anteaters are insectivorous and of infected sandflies are very difficult to perform. Some occasionally pass the day in a hollow tree and, while workers failed even when they used sandfly species foraging for ants and térmites, they could inadvertantly that were undoubted vectors, on epidemiological eat the odd reduviid. However, the only insects found in grounds. Conversely it may be possible to transmit a more than 150 Tamanduá stomach and fecal samples Leishmania with a sandfly that in nature never comes which were not ants or térmites were homopteran mimics into contact with the reservoir. This may give a false of ants. Armadillos are, however, terrestrial, live in bur- indication to the role of a particular group of insects as rows and are omnivorous, and clearly stand a greater vectors because it does not indicate the vector in a real chance of becoming infected with T. cruzi than sloths or epizootiological situation. The definition of a vector of a anteaters. T. cruzi infections are commonest in armadil• hemoflagellate depends upon a combination of both los, relatively rare in Tamanduá anteaters and very rare field and laboratory studies. in sloths, suggesting that there is a correlation between None of the vectors of the trypanosomes found in food and behavioral habits and infection with this hem• xenarthrans are known but almost certainly those of the oflagellate. different T. cruzi-Vke infections and T. leuwenhoeki are Our present fragmentary knowledge of incidences of reduviid bugs. There is good evidence that the reduviid mked infections indicates that the habitat plays a major bug Panstrongylus geniculatus is the vector of zymo• role in determining the type of parasite, especially when deme III that is found in common long-nosed armadillos; transmission is by bite. It seems, however, that such however, more observations are needed before this bug factors as food habits can assume special importance in can be considered as the actual vector. More Information the case of trypanosomatids whose transmissions are by is needed on the susceptability of different sandfly and passive contamination with contaminated insect fecal bug species to the now identifiable strains and subspecies material. r of the different hemoflagellates, especially their cycles of development in the different species. Further studies on the hematophagus insects that feed on sloths, VECTORS OF XENARTHRAN HEMOFLAGELLATES anteaters, and armadillos in the wild could give im• portant leads to possible vectors. Many insects have been incriminated as vectors of Godfrey (1979) suggested that the different isoen• hemoflagellates simply because they have been found to zymes seen in the various zymodemes of T. cruzi might be naturally infected in enzootic or endemic regions. be adaptions to optimal development and transmission Such Information is obviously very important for it in certain bugs. There is therefore an increasing amount supplies primary leads, but these species may represent of support for the idea that each trypanosomatid has dead end infections that, for various reasons, are never one major vector and presence or absence of the vector transmitted to a susceptable host. Epizootiological and is the limiting factor in distribution of the trypano• experimental evidence conclusively indicates that the somatid rather than distribution of the reservoir host. sandfly L. (N.j trapidoi is the major vector of L. b. panamensis among sloths but no actual transmissions XENARTHRA AS RESERVOIRS OF LEISHMANIAL have yet been performed. The vectors of the other AND TRYPANOSOMAL INFECTIONS OF MAN leishmanias of sloths and armadillos are unknown, but it is likely that they are phlebotomine sandflies. There To incriminate an animal as a reservoir of a human seems little doubt that the sandfly L. (N.j umbratalis is disease it is first necessary to show that the organism the vector of the L. b. guyanensis infections found in C. found in it is identical to the disease organism found in didactylus sloths and 7! tetradactyla anteaters, but it man, and then to show that it is the major host rather seems likely that L. (N.j whitmani could be an im• than an accidental one. A single record of a particular

Hemoflagelates of Xenarthrans 2W parasite in a wild animal species does not mean that it is evaluate the importance, if any, of T. cruzi infections in a reservoir, especially if no other infections were found sloths and anteaters to human Chagas' disease. To begin in other individuais caught in the same habitat. with, comparisons need to be made with stocks isolated In Panamá, two-toed sloths C hoffmanni are the major from these animais and man. reservoirs of L. b. panamensis, the causitive agent of In Panamá, man is infected with a T. rangeli-like cutaneous leishmaniasis of man. Leishmanial stocks trypanosome that is very similar to T. leuwenhoeki of isolated from sloths appeared to be biologically and sloths. The high incidence of infection of this trypano• biochemically the same as those isolated from man. In some in both species of sloth from the more open áreas extensive studies on the infection rates of L. b. pana• leaves no doubt as to the importance of these animais as mensis in wild animais, Herrer et al. (1973) found that in reservoirs. If some of the T. rangeli-like infections in endemic áreas up to 37 percent of the two-toed sloths man prove to be the same as T. leuwenhoeki, then sloths were infected with this parasite. The importance of would be incriminated as a potential source of infection two-toed sloths as reservoirs of L. braziliensis subspecies for man. Whether or not sloths could serve as a direct in other Latin American countries has yet to be source for the bugs that bite man or as a source of determined. Infections have been found in two-toed infection for bugs that transmit the infection to a sloths near the Amazon river but the parasite has not yet domestic animal that then serves as a reservoir for some been sufficiently well characterized to associate it with domestic bug is an important facet that needs to be human infections. Common long-nosed armadillos have investigated in relation to both T. cruzi and T. been found infected with a Leishmania by Lainson et al. leuwenhoeki. In certain regions armadillos, anteaters and (1979a) in the lower Amazon Basin, but so far this sloths are eaten by man. There is thus a direct risk of parasite has not been found in man. The finding of infection, principally with T. cruzi, associated with the infections of L. b. guyanensis in 46 percent of the preparation and consumption of the animal. two-toed sloths C. didactylus from an endemic "pian-bois" region of northern Pará clearly indicates TRYPANOSOMATID EVOLUTION EM RELATION TO them to be the major reservoir. An infection rate of 22 XENARTHRAN HEMOFLAGELLATES percent in anteaters T. tetradactyla means that these must also be considered as important secondary The lack of fóssil evidence for most of the Protozoa reservoirs (Lainson et al, 1981a, 1981b). The relative makes it difficult to construct a phylogenetic scheme importance of different reservoirs can only be assessed that can be confidently supported. Most schemes are by comparing infection rates in laboratory-bred natural therefore by necessity based on living organisms. In an vectors fed on wild-infected vertebrate hosts. This is excellent review on the radiation of the technically difficult, and normally the infection rate in Protista (Protozoa, Algae, and some Fungi) Sleigh different wild animais is used as an indication of their (1979) concluded that the primitive nucleus of kineto- importance as reservoirs. plastids suggests that they evolved directly from the Brazilian stocks of T. cruzi from common long-nosed basic primitive flagellate stock. armadillos of Bahia and Pará belong to zymodeme III There are no reasons for rejecting leptomonads as (Barrett et al., 1980; Miles et al., 1981), but we know the basic stock of the kinetoplastids and invertebrates as nothing about stocks from these animais in other parts their original hosts (Baker, 1965). It should be noted of the continent. Zymodeme III is rare in man and has that Leishmania develop as promastigotes only been found in 4 acute cases of Chagas' disease (leptomonads) in their vectors, phlebotomine sandflies, (Miles et al., 1979a) that ali became infected at and that these insects are considered as perhaps the most apparently the same time in the capital of Pará state primitive of the blood-sucking Diptera, originating (Shaw et al., 1969). In endemic Chagas' disease regions possibly as long ago as the Triassic (Edwards, 1926). For where human isolates have been studied (Miles et al., the above reasons, parasites of the genus Leishmania, 1977; Barrett et al., 1980), none belonged to zymodeme especially the leishmania of lizards, are considered to be III. the most primitive hemoflagellates. Baker (1965) dealt The available evidence, therefore, suggests that the at length with the various theories on the evolution of zymodeme of T. cruzi associated with common long- the trypanosomatids and concluded that the genus nosed armadillos seldom infects man. However, there Trypanosoma is polyphyletic, having evolved along three was no association of armadillos or bugs, such as the separate lines that diverged from a primitive hypo- reduviid P. geniculatus, with the patients from Pará. The thetical leptomonad stock of annelids. Based on the position of common long-nosed armadillos as reservoirs biology of certain hemoflagellates of xenarthra, in in the complex epidemiology of Chagas' disease clearly particular Endotrypanum, I suggested (Shaw, 1966) that needs to be investigated in greater detail, especially the the subgenus Schizotrypanum in the New World and the enzyme profiles of T. cruzi isolates from this species of genus Endotrypanum could have both evolved from the armadillo and man in other countries. It is difficult to insect leptomonad stock.

Jeffrey J. Shaw In the past 15 years, much more Information has blood-stream phase being a result of convergent become available on the trypanosomatids of xenarthrans evolution." Zymodemes I, II, and III of T. (S.) cruzi which supports the line of evolution that I suggested in from man may be readily differentiated on at least 5 1966, and supports the idea that there may have been a enzymes (Miles et al., 1980), suggesting a difference that line that was particularly associated with xenarthrans. in the future may warrant taxonomic status. The above The Leishmania found in sloths and armadillos are observations add weight to Godfrey's "heretical peripylarians, a group found only in the Américas and possibility". The observations suggest that there may be considered to be intermediate between the primitive different lines of Schizotrypanum that are infective to hypopylaria of lizards and the more advanced supra• man and that they could have evolved independently in pylaria of rodents (Lainson and Shaw, 1979). some xenarthran stock, such as armadillos, and in other Our present knowledge of the hosts and geographical primitive mammals, such as marsupials. Evidence that distribution of peripylarian Leishmania strongly evolutionary pressures on a leishmanial stock of extinct supports the idea that this group evolved in xenarthrans. xenarthrans could have selected the trypomastigotic There is at present considerable controversy about the form comes from the present-day bloodstream forms of origin of some mammalian Leishmania found in the Endotrypanum. Neotropics, particularly those responsible for the visceral form of the disease in man. Cameron (1956) has ACKNOWLEDGMENTS suggested that the genus Leishmania was introduced by man from the New World to the Old World after This work was generously supported by the Wellcome Columbus' voyage, while others consider that certain Trust, London, and the Fundação SESP of the Brazilian parasites were introduced from the Old World to the Ministry of Health, Rio de Janeiro. 1 am particularly New World. This is not the place to discuss the effect indebted to my friends and coUeagues for allowing me to man has had on the continental dispersion of leishman• cite results from manuscripts that are at present in press iasis, but I think that our present knowledge of the and for their permission to quote unpublished obser• biology of the peripylarian leishmania of xenarthrans vations. Special thanks are due to Drs. Ralph Lainson poses a fundamental question. Did the suprapylaria and Michael A. Miles for their stimulating and very evolve from a peripylarian stock or do they represent a valuable discussions. separate line of evolution? Although the evidence is scant, I think that we should seriously consider the LITERATURE CITED possibility that the suprapylaria evolved from the more primitive peripylarians and that rodents could have Baker, J.R. been responsible for their spread from the New World 1965. The evolution of parasitic protozoa. Pp 1-27 in to the Old World. Third symposium of the British Society for Another line of evolution in xenarthrans has resulted in Parasitology, Evolution of Parasites (A.E.R. flagellates of the genus Endotrypanum that have char- Taylor ed.). Blackwell Scientific PubUcations, acters intermediate between those of the leishmania and Oxford, 133 pp. trypanosomes. In insects they develop as do parasites of the genus Leishmania, while in the blood of the sloth Baker, J. R., M. A. Miles, D. G. Godfredy, and T.V. they are in the form of epimastigotes and, in one rare Barrett. species, they have a trypanomorphic form. The genus 1978. Biochemical characterization of some species of Endotrypanum is perhaps a living example of the an- Trypanosoma (Schizotrypanum) from bats cestoral form of some trypanosomes that has survived (Microchiroptera). Am. J. Trop. Med. Hy., 27: because of the antiquity of both its vectors and reservoir 483-491. hosts. The idea that trypanosomes of the subgenus Schizo• Barrett, T. V., R. F. Hoff, K. E. Mott, M. A. Miles, D. G. trypanum represent a third line that could have Godfrey, R. Texeira, J. A. Almeida de Sourza, and I.A. developed in xenarthrans needs to be examined in the Sherlock. light of recent biochemical observations on members of 1980. Epidemiological aspects of three Trypanosoma this subgenus. Godfrey (1979) pointed out that eight cruzi zymodemes in Bahia. Trans. R. Soe. Trop. zymodemes of Schizotrypanum from bats (Baker et al., Med. Hyg., 74: 84-90. 1978) bore no resemblance to T. (S.) cruzi from man (Miles, 1979). He suggests that "the heretical possibility Baretto, M. P., and R. D. Ribeiro. should be contemplated that these trypanosomes (re- 1979. Reservatórios sUvestres do Trypanosoma (Schizo• ferring to T. (S.) dionisii and T. (S.) vespertilionis of trypanum) cruzi Chagas, 1909. Rev. Inst. Adolfo European bats) are not closely related to each other or Lutz., 39: 25-36. to T. (S.) cruzi, their identical morphology in the

Hemoflagelates of Xenarthrans 289 Cameron, T. W. M. Salgado, Estado do Pará. Rev. Inst. Med. Trop. 1956. Parasites and parasitism. Methuen and Co., Ltd, São Paulo, 3: 61-70. London, 322 pp. D'Alessandro, A. Chagas, C. 1976. Biology of Trypanosoma (Herpetosoma) rangeli 1912. Sobre um trypanosoma do tatu, Tatusia novem- Tejera, 1920. Pp. 327-403 in Biology of the cincta, transmitido pela Triatorm geniculata Kinetoplastida. Vol I (W.H.R. Lumsden and D.A. Latr. (1811). Possibilidade de ser o tatu um Evans eds). Academic Press, London, New York depositário do no mundo and San Francisco, 563 pp. exterior. Brasil méd., 26: 305-306. Edwards, F. W. Chance, M. L. 1926. The phylogeny of nematocerous Diptera: a 1979. The identifcation of Leishmania. Pp 53-74 in criticai review of some recent suggestions. Ver- Symposia of the British Society for Parasitology, handl. III Internat. Kong. Ent., 2:111. Volume 17, Problems in the Identification of Parasites and Their Vectors (A. E. R. Taylor and Freitas,!. L.P. R. Muller, eds.). Blackwell Scientific Publicat- 1950. Observações sobre xenodiagnòsticos practicados ions, Oxford, 221 pp. em reservatórios domésticos silvestres do Trypan• osoma cruzi em uma localidade endémica da Christensen, H. A., and A. Herrer. moléstia de Chagas no Estado São Paulo. O 1973. Attractiveness of sentinel animais to vectors of Hospital (Rio de Janeiro), 38: 521-529. leishmaniasis in Panamá. Am. J. Trop. Med. Hyg., 22: 578-584. _ Gentile, B., F. Le Pont, F.X. Pajot, and R. Besnard. 1976. Neotropical sandflies (Diptera: Psychodidae), 1981. Dermal leishmaniasis in French Guiana: the sloth invertebrate hosts of Endotrypanum schaudinni {Choloepus didactylus) as a reservoir host. Trans. (Kinetoplastida: Trypanosomatidae). J. Med. R. Soe. Trop: Med. Hyg., 75(4): 612-613. Entomol., 13: 299-303. Godfrey, D. G. 1979. Susceptability of sandflies (Diptera:Psychodidae) 1979. The Zymodemes of Trypanosomes. Pp. 31-53,/« to trypanosomatidae from two-toed sloths Symposia of the British Society for Parasitology, (Edentata: Bradypodidae). J. Med. Entomol., Volume 17, Problems in the Identification of 16: 424-427. Parasites and Their Vectors (A.E.R. Taylor and R. Muller eds.). Blackwell Scientific Publications, Clark, H. C, and L. H. Dunn. Oxford, 221 pp. ., ^ 1932. Experimental studies on Chagas' disease in Pana• má. Am. J. Trop. Med., 12: 49-77. Herrer, A., and S. R. Telford. 1969. Leishmania braziliensis isolated from sloths in Croft, S. L., M. L. Chance, and P. J. Gardener. Panamá. Science, 164: 1419-1420. 1979. Ultrastructural and biochemical characterization of strains of Endotrypanum. Trans. R. Soe. Herrer, A., H. A. Christensen, and R. J. Beumer. Trop. Med. Hyg., 73: 322. 1973. Reservoir hosts of cutaneous leishmaniasis among Panamanian forest mammals. Am. J. 1980. Ultrastructure and biochemical characterization Trop. Med. Hyg., 22: 585-591. of stocks of Endotrypanum. Ann. Trop. Med. Parasitol., 74, 585-589. Hershkovitz, P. 1971. Edentata. Encyclopedia Britannica, 7: 965-968. Deane, L. M. 1961. Tripanosomideos de mamíferos da região Ama• Hoare, CA. - zônica. I. Alguns flagelados encontrados no 1972. The Trypanosomes of Mammals. A Zoological sangue de mamíferos silvestres do Estado do Monograph. Blackwell, Oxford and Edinburgh, Pará. Rev. Inst. Med. Trop. São Paulo, 3:15-28. 749 pp.

Deane, L. M., and R. G. Damsceno. Lainson, R. 1961. Tripanosomideos de mamíferos da região Ama• 1965. Parasitological studies in British Honduras. I. A zônica. II. Tripanosomas de macacos da Zona do » parasite resembling Trypanosoma (Schizotry-

2â0 ;vW'" Jeffrey J. Shaw panumj cruzi in the coati, Nasua narica (Carniv- 1977. Epidemiological studies of Chagas' disease in ora, Procyonidae), and a note on Trypanosoma Brazil. Trans. R. Soe. Trop. Med. Hyg., 73: legeri from the anteater, Tamanduá tetradactyla 135-136. (Edentata). Ann. Trop. Med. Parasit., 59: 37-42. Miles, M.A., P.J. Toye, S.C. Oswald, and D.G. Godfrey. Lainson, R., and J. J. Shaw. 1979. The Identification by isoenzyme patterns of two 1979. The role of animais in the epidemiology of South distinct strain-groups of Trypanosoma cruzii American leishmaniasis. Pp. 1-116 in Biology of circulating independently in a rural area of the Kinetoplastida. Vol. II (W. H. R. Lumsden Brazil. Trans. R. Soe. Trop. Med. Hyg., 71: and D. A. Evans, eds.). Academic Press, London, 217-255. New York and San Francisco, 738 pp. » Miles, M. A., A. Souza, M. Povoa, J. J. Shaw, and R. Lainson, R., J. J. Shaw, and R. D. Naiff. Lainson. 1980. Chagas' disease in the Amazon Basin: suggestions 1978. Isozymic heterogeneity of Trypanosoma cruzi ia on transmission per os. Rev. Inst. Med. Trop. the first autochthonous patients with Chagas' São Paulo, 22: 294-297. disease in the Amazonian Basin. Nature, Lond., 272:819-821. , Lainson, R., J. J. Shaw, and M. Povoa. 1981. The importance of edentates (sloths, anteaters) Miles, M. A., S. M. Lanham, A. S. de Souza, and M. as primary reservoirs of Leishmania braziliensis Póvoa. guyanensis. Trans. R. Soe. Trop. Med. Hyg., 1980. Further enzymic characters of Trypanosoma 75(4): 611-612. cruzi and their evaluation for strain Ident• ification. Trans. R. Soe. Trop. Med. Hyg., 74: Lainson, R., J. J. Shaw, H. Fraiha, M. A. Miles, and C. C. 221-237. _^ Draper. 1979. Chagas' disease in the Amazon Basin: I. Trypan• Miles, M. A., M. Povoa, A. A. Souza, R. Lainson, and J. osoma cruzi infections in silvatic mammals, J. Shaw. triatomine bugs and man in the state of Pará, 1981. Chagas' disease in the Amazon Basin: II. The north Brazil. Trans. R. Soe. Trop. Med. Hyg., 73: distribution of the Trypanosoma cruzi zymo• 193-204. demes 1 and 3 in Pará state, north Brazil. Trans. R. Soe. Trop. Med. Hyg., 75: 667-674. Lainson, R., J. J. Shaw, R. D. Ward, P. D. Ready, and R. D. Naiff Montgomery, G. G. 1979. Leishmaniasis in Brazil: XIII. Isolation of Leish• 1985. Movements, Foraging and Food Habits of the Four mania from armadillos (Dasypus novemcinctus) Extant Species of Neotropical Vermilinguas and observations on the epidemiology of cutan• (Mammalia; Myrmecophagidea) (this volume). eous leishmaniasis in North Pará State. Trans. R. Soe. Trop. Med. Hyg., 73: 239-242. - ^ Montgomery, G. G. and M. E. Sunquist. Lainson, R., J. J. Shaw, P. D. Ready, M. A. Miles, and M. 1978. Habitat selection and use by two-toed and three- Póvoa. toed sloths. Pp. 329-359 in The Ecology of 1981. Leishmaniasis in Brazil: XVI. Isolation and iden- Arboreal Folivores (G. G. Montgomery, ed.). tification of Leishmania from sandflies, wild Smithsonian Institution Press, Washington, D.C. mammals and man in north Pará, with particular 574 p. reference to Leishmania braziliensis guyanensis, caustive agent of "pian bois." Trans. R. Soe. Newton, B. A., and J. K. Burnett. Trop. Med. Hyg., 75(4): 530-536. 1972. DNA of kinetoplast: a comparative study. Pp. 127-138 in Comparative Biochemistry of^ Miles, M. A. Parasites (H. van den Bossche, ed.). Academic • 1979. Transmission cycles and the heterogeneity of Press, New York and London. 516 p. Trypanosoma cruzi. Pp. 117-196 in Biology of the Kinetoplastida. Vol. II (W. H. R. Lumsden and D. A. Evans, eds.). Academic Press, London, New York and San Francisco, 738 pp.

Miles, M. A., T. V. Barrett, R. H. Hoff, and K. E. Mott.

Hemoflagelates of Xenarthrans 291 Pipkin, A. C. occasion of his 80th birthday, 1981 (E.V. 1968. Domicillary reduviid bugs and the epidemiology Canning, ed.). Soe. Protozol., Specpl Publ. 1. of Chagas' disease in Panamá (: Reduv- iidae: ). J. Med. Entomol., 5; 107- Shaw, J. J., and R. G. Bird. 124. 1969. The endoerthrocytic habitat of a member of the trypanosomatidae, Endotrypanum schaudinni Rey-Matiz, H. Mesnil and Brimont, 1908. Z. Tropenmed. 1941. Observaciones sobre trypanosomas en Colômbia. Parasit., 20: 144-150. I. Observaciones sobre Trypanosoma cruzi. Rev. Fac. Med. Bogotá, 10: 25-49. Shaw, J. J., R. Lainson, and H. Fraiha. 1969. Considerações sobre a epidemiologia dos primeiros casos autóctones de Doença de Chagas Rodrigues, B. A., and G. B. MeUo. registradas em Belém, Pará, Brasil. Rev. Sàude 1942. Contribuição ão estudo do tripanosomiase Publ., São Paulo, 3: 153-157. americana. Mem. Inst. Oswaldo Cruz, 37: 77-90. Sleigh, M. A. Sarich, V.M. 1979. Radiation of the Eukaryote Protista. Pp. 23-53 1985. Xenarthran systematics: albumin immunological in The Systematics Association Special Volume evidence. (this volume). * No. 12, The Origin of Major Invertebrate Groups (M. R. House, ed.). Academic Press, London, Shaw, J. J. * New York and San Francisco. 515 p. 1964. A possible vector of Endotrypanum schaudinni of the sloth Choloepus hoffmanni in Panamá. Sunquist, M. E. and G. G. Montgomery. Nature, Lond., 210: 107-108. 1973. Activity patterns and rates of movement of two-toed and three-toed sloths {Choloepus hoff• 1966. The relationship of Endotrypanum to other manni and Bradypus infuscatus). Journal of members of the Trypanosomatidae and its Mammalogy, 54: 946-954. possible bearing upon the evolution of certain haemoflagellates of the New World. Proc. First. Walton, B. C, and O. E. Sousa. Internat. Congress Parasit., Rome 1964., 1: 1967. Trypanosomes of the lesser anteater. Tamanduá 332-333. tetradactyla, from Panamá. J. Parasit., 53: ^ 956-961. 1969. The Haemoflagellates of Sloths. London School of Hygiene and Tropical Medicine Memoir Wilcock, C, and P. E. C. Manson-Bahr. No. 13., H.K. Lewis and Co. Ltd., London. 132 1974. Manson's Tropical Diseases. Bailliere Tindall, London. 110 p. . - P-

1981. The behaviour of Endotrypanum schaudinni Zeledon, R., C. Ponce, and E. de Ponce. (Kinetoplastida Trypanosomatidae) in three 1975a The isolation of Leishmania herreri sp. n. from species of laboratory-bred Neotropical sandflies sloths in Costa Rica. Am. J. Trop. Med. Hyg., (Diptera: Psychodidae) and its influence on the 24: 706-707. classification of the genus Leishmania. Pp. 232-241 in Parasitological topics, a presentation 1975b. Isolation of Trypanosome rangeli from Costa volume to P.C.C. Garnham F.R.S. on the Rican sloths. Am. Soe. Parasit. Program and Abstracts, 60.

Zeledon, R., C. Ponce, and J. Murillo. 1979. Leishmania herreri sp. n. from sloths and sand• flies of Costa Rica. J. Parasit., 65: 275-279.

293 Jeffrey J. Shaw