703

An outbreak of acute Chagas’s disease in the Sao Francisco Valley region of Bahia, : triatomine vectors and reservoirs of cruzi

T. V. BARRETT* Dept. of Entomology, London School of Hygiene and Tropical Medicine, Keppel Street, London WClE i HT

R. HOFF*, K. E. MOTT* Dept. of Tropical Public Health, Harvard School of Public Health, 6fi.J Huntington Ave., Boston, MA. IlZll~i, USA

F. GUEDES Faculdade de Medicina, Universidade Federal da Bahia, Salvador, Bahia, Brazil

AND

I. A. SHERLOCK Nucleo de Pesquisas da Bahia, Funda@o Oswald0 Cruz, Salvador, Bahia, Brazil

Summary was diagnosed in eight patients aged seven to 65 Following reports of an unusually high incidence years from the administrative district (“municipio”) of acute Chagas’s disease and the appearance of of Riacho de Santana, who had been admitted to the large numbers of infesrans in the south- Hospital Professor Edgard Santos of the Federal western region of the State of Bahia, triatomine University of Bahia in Salvador. These patients and bugs (: ) and domestic their relatives knew of many similar cases and in one of the affected communities were surveyed reported that houses in the area had recently become and examined for infection with . heavily infested with triatomines. This unusual was prevalent in houses and was clustering of acute cases, and reports of heavy also found in peridomestic habitats. T. sordidu and infestations by Triatoma infestans, prompted us to T. pseudomaculata occupied peridomestic and investigate this outbreak with the aid of the national svlvatic habitats and T. brasiliensis was found onlv, vector control service (SUCAM). among rocks far from houses. megistus, In this report we describe the distribution of formerly present in the region, was not found. triatomine vectors and reservoir hosts of Trypano- Trypanosoma cruzi was detected in 19.5 ‘Iii of soma cruzi in a rural community in Riacho de Triatoma infestans, 11.5”,, of T. sordida, 19”,, of Santana. The results of clinical and serological dogs, 29:,, o f cats and 100” u of rats examined. A studies and of biochemical characterization of dlsproportionate number of early instar bugs were T. cruzi from this area will be discussed elsewhere. infected with Trypanosoma cruzi, suggesting that a rapid increase in the rate of transmission had Materials and Methods recently occurred. The study area The history of the domestic triatomine fauna of The municipio (administrative district) of Riacho the region since 1912 is reviewed, and it is proposed de Santana covers 3708 km2 in the Serra Geral that the relatively recent arrival of Triatoma region of the state of Bahia and the urban area infestans initiated a domestic cycle linked to peri- is situated 60 km east of the Sgo Francisco river domestic and sylvatic cycles of’ TryDanosoma cruzi (Fig. 1). The 1970 census recorded a total population transmission. Increased human mobility, the use of of about 30,000, of whom 87 96 were rural residents, DDT for malaria control. and drought conditions and the estimated population in 1976 was 34,000. are considered as factors which miiht have con- The vegetation is predominantly xeromorphic tributed to the outbreak of human infection. deciduous woodland and scrub (“caatinga”) (HLJECK, 1960-61). The single rainy season lasts from Introduction October to March. During the previous 10 years the Most epidemiological studies of Chagas’s disease mean annual rainfall had been 822 mm. Maximum have been carried out in regions of stable trans- and minimum temperatures were 39.1”C and lO”C, mission of Trypanosoma cruzi. Serological evidence and the average monthly temperature ranged from suggests that in such regions most of the initial 22.7”C to 28.9%. A drought in 1975 and 1976 infections are acquired before the age of 20, often without any evident acute phase of illness (MOTT *Consultants to the Pan American Health Organiza- et al., 1976). During 1975, acute Chagas’s disease tion. ACUTE CHAGAS’S DISEASE IN BRAZIL: VECTORS AND RESERVOIRS OF T. cruzi

‘I

Fig. 1. Bahia and neighbouring states. Fig. 2. Houses CEM 21 and CEM 22 in Barreiro Vermelho. Note . . -I- Munlclplo m Bahia with T. inferrurrr in 1956 (based on Dtns & the crevices between bricks where the wall is unplastered, the maize SEREBRENICK, 1958) store behind the houses, and the proximity of the woodland in the s Municipios in Bahia with T. i&vtour in 1971 (based on SHERLOCK background. & SERAFIM, 1972) severely affected production of cattle, maize, cotton remainder were solidly built and had wholly or and beans, on which the economy of the region partially plastered brick walls (Fig. 2). All had tiled depends. Commerce has traditionally been linked roofs. Houses were spaced from 20 to 400 meters with the States of S;io Paulo and Minas Gerais, apart. A peridomestic area, in most cases enclosed and many residents have at some time travelled to by a wooden fence, usually contained a structure SZo Paula in search of jobs. Until 1950 communica- used for storing maize (Fig. 2), a chicken house, tions with these states were mainly dependent on loose boards, spare tiles and often a pig-pen. In the River Sgo Francisco but, since then, traffic has many cases this peridomestic area was directly increasingly moved by lorry on new roads connect- adjacent to the surrounding woodland. ing the region with Minas Gerais. Traffic is heaviest during August and September, when up to 2000 Survey of triatomines lorries carrying pilgrims to the town of Born Jesus Two assistants searched the inside of each house da Lapa (indicated as “Lapa” in Fig. 1) pass for 20 min using torches and forceps while a third through Riacho de Santana from the south. searched fence posts, chicken houses and other Malaria, formerly an important disease, has been likely habitats in the peridomestic area. In sylvatic brought under control by spraying houses with areas remote from houses we searched tree holes, DDT, and the spraying programme was still in the bark of dead trees, fence posts and outcrops of operation in 1976. In 1969, local physicians diag- rock. Rupicoline (rock-inhabiting) triatomines were nosed the first cases of an outbreak of acute Chagas’s induced to emerge from their hiding places by the disease. About 50 cases had been reported in the presence of the collectors, who sat quietly and three years before our visit in March, 1976. captured the bugs as they approached to feed in full A rural community 9 km from the town of Riacho daylight. Captured bugs were placed in plastic pots de Santana was selected for intensive study. The containing filter paper to absorb the faeces and community comprises the Fazenda (rural area) transported to the laboratory in insulated boxes. Barreiro Vermelho and two houses of a neighbouring Triatomine eggs were collected from two houses Fazenda. The most recent case of acute Chagas’s in the town of Riacho de Santana and from two disease known to us had occurred in this community. houses and a peridomestic enclosure in Barreiro With the help of the local staff of SUCAM we Vermelho, and examined for evidence of parasitism prepared a map and took a census: 21 households by microhymenoptera. with 120 residents and their 28 dogs and 35 cats were studied. Survey of reservoir hosts Two of the houses were of mud and wattle Of the 63 dogs and cats in the study area, 57 were construction with unplastered walls, while the subjected to xenodiagnosis with five fifth-instar T. V. BARRETT et d. 705

Table I-Distribution of Triatoma infestans and T. sordidain housesand peridomesticareas, and number of bugs infected with Trypanosoma cruzi. Fazenda Barreiro Vermelho, Riacho de Santana, March 1976

Houses Peridomestic Area

T. infestans T. sordida T. infestans T. sordida CEM number total I total -t total + total 14 2 - 106 23 8 3 11 1 i - 1 0 14 0 3 2 0 0 - - 1 0 4 0 - - 2 0 5 39 1 : - 3 r 0 - 10 13 0 0 - 0 - 4 0 11 20 0 0 - 0 - 14 0 12 2 0 0 - 0 0 - 14 6 - 6 Ti 0 - 15 6 z : - 32 11 16 cl 18 2 0 - : - 0 - 16 c2 1 0 - 1 0 11 1 16 c3 z 1 0 1 0 5: 0 16 c4 13 : 0 - 1 0 17 cl 11 2 0 - 2 i 18 3 1 0 - ii - 0 - 19 2 0 0 - 0 - 9 0 *21 2 0 0 - i - 0 - **22 28 7 0 - 0 - *23 0 - 0 - 0 - 0 - PL ICI 30 21 0 - - PL 2 - - - - 1

Total 229 44(19.2”;) 1 0 119 24(20.2”,,) 155 18(11.6”,,)

-I- number positive for T. cruzi * sprayed with BHC several days before sampling **house abandoned for 3 months before sampling

Table II-Rate of Trypanosoma cruzi infection in Triatorna infestans and in T. sordida according to develoDmenta1 stage of the bugs. Barreiro Vermelho, March 1976

T. infestans T. sordida

Stage No. examined “,, positive No. examined (I(, positive

I 4 0 33 0 II 10 10.0 10 30.0 III 23 34.8 5 0 IV 45 15.6 15 20.0 V 151 21.9 32 15.6 adult 115 17.4 61 11.5 Total 348 19.8 156 11.5

nymphs of Triatoma infestans or prolixus (“Nembutal”: May and Baker Ltd.) and subjected from the colony of the Nucleo de Pesquisas da to xenodiagnosis with five fifth-instar nymphs of Bahia. Rats (Rattus rattus) were captured with T. infestans and five fifth-instar nymphs of R. “Whole Family” rat traps (S. Young & Sons Ltd., prolixus. At the same time, tail blood from each rat Misterton, Somerset, U.K.) that were baited with was examined microscopically for trypanosomes and cheese and bacon and placed near the houses. For several drops were inoculated into a fortified NNN parasitological examination the rats were anaesthe- blood agar slant with F29 medium as overlay tized with intraperitoneal pentobarbitone sodium (PAN, 1968). 706 ACUTE CHAGAS'S DISEASE IN BRAZIL:VECTORS AND RESERVOIRS OF T. CrUzi

Examination of triatomines from a peridomestic enclosure in Barreiro Vermelho 25 to 35 days after feeding, the rectum and had exit holes made by parasitoid wasps which, posterior midgut of each of the bugs used in when reared from parasitized eggs were-identified xenodiagnosis were dissected into physiological as Telenomus fariai Costa Lima, 1927 (Scelionidae). saline solution on a microscope slide. Each slide One fifth-i&ar Triatoma so&da from the same was scanned using the 10 x objective for 12 to enclosure was parasitized by a mermithid larva- 15 min or until flagellates were seen. Bugs collected the first time that any triatomine has been found in the survey were examined in the same way. naturally parasitized by a nematode. A high pro- portion of T. brasiliensis was heavily infested with Results sporocysts of a protozoan resembling Hepatozoon Triatomines triatomae (Osimani) (Haemogrenarinidae). The triatomine species encountered in Riacho While collecting bugs inside houses. we were de Santana were Triatoma infestans (Klug, 1834), impressed by the absence of known predators of T. sordida (Stal, 1859), T. brasiliensis Neiva, 1911 triatomines. In contrast, associated with the peri- and T. pseudomaculata Correia & Spinola, 1964. domestic habitats of T. sordida, there was an Table I shows the domestic/peridomestic distri- abundance of spiders, lizards and reduviids of the bution of the captured bugs and the number infected snecies Microtomus tibialis Stichel, 1926 (Reduviidae: with Trypanosoma cruzi. Triatoma infestans was Microtominae). M. tibialis, which was also found found in 19 of the 22 houses examined, including in tree holes with T. pseudomaculata, readily killed one which had been abandoned by its owners three T. sordida in the laboratory. Older residents of months previously but in which pigs and chickens Barreiro Vermelho remarked that spiders and were still kept. With the exception of a single adult geckoes had formerly been common inside houses T. sordida, all the bugs found in houses were T. but that now only triatomines and cockroaches infestans. (BlatteZla germanica) were seen. T. sordida was the predominant species in the The apparent absence of spiders and of T. fariai peridomestic area where it was found mainly in inside houses could well be due to DDT residues; fencing, loose timber and other wooden structures. wall scrapings taken from four houses in May 1976 T. infestans was also present in peridomestic and analysed by gas-liquid chromatography in habitats, particularly at house CEMl which differed January 1977 at the Monks Wood Experimental from the others in having a brick annex to the house. Station (England) contained 220 to 745 (mean 505) In this annex, 17 of 23 (74”,6) bugs from a rat- pg of DDT per g. infested storage box and nine of 91 (loo/“) bugs from a brick wall where chickens roosted were Reservoir hosts infected with Trypanosoma cruzi. Of the 21 households, 17 had one or more dogs A single, uninfected adult Triatoma pseudo- and 17 had one or more cats. Trypanosoma cruii maculata was found in a chicken house. was detected by xenodiagnosis in five of 26 dogs Bugs infected with Trypanosoma cruzi were (1976) and nine of 31 cats (29sb). Ten households found in 501” of the houses and 27:; of the (48 T,,) had at least one infected dog or cat. peridomestic enclosures. Over-all, 19 to 20:” of Of the 10 rats captured, all were positive for T. Triatoma infestans and 11.5 VU of T. sordida were cruzi by xenodiagnosis and by haemoculture. In infected with Trypanosoma cruzi. addition, nine of the rats also had a microscopically Table II shows the prevalence of T. cruzi in patent parasitaemia with T. lewisi. The one Triatoma infestans and T. sordida according to the (DideZphis albiventris) trapped in the study area was developmental stage of the bugs. In both species, positive for T. cruzi by xenodiagnosis, haemoculture the infection rate was higher in nymphs than in and direct examination of the blood but two wild adults and higher in adult females than in adult cavies (Cavia apera) were negative by all examina- males (T. infestans females 24.1 “/b, males 11.5 96 ; tions. T. sordida females 17.6 “,&, males 3.7 0/0). In the urban area of Riacho de Santana 3291 of Discussion 97 T. infestans collected from four houses known to Domestic Triatominae in western Bahia be heavily infested were positive for Trypanosoma Changes in the domestic triatomine fauna of cruzi. western Bahia, particularly along the Sao Francisco In the woodland we found seven Triatoma and Rio Grande rivers (Fig. I), have been relatively pseudomaculata and one T. sordida in treeholes that well documented and it is thus possible to consider also contained lizards, feathers, hairs of the primate our present findings in an historical context. Callithrix sp. and a nest. One T. sordida and Triatoma pseudomaculata* and T. sordida-species one T. pseidomaculata were found in fence posts far not generally considered to be important vectors of from houses. 20 individuals of a dark varietv of Trypanosoma cruzi to man-have been found in T. brasiliensis were captured among boulders of settlements along the S%o Francisco river at least granitic gneiss inhabited by lizards (Tropidurus since 1912, and early authors remarked on the torquatus and other species) and rock cavies (Kerodon rupestris). None of these sylvatic or rupicoline bugs * Triatoma maculata (Erickson, 1848) in the earlier was infected with Trypanosoma cruzi. Brazilian literature of T. pseudomaculata Correia & Spinola, 1964 in later papers probably refer to the Predators and parasites of triatomines same species, but opinions on their synonomy and None of 795 eggs of T. infestans had any signs of distribution are confused (e.g. SHERLOCK & SERAFIM, parasitism. However, nine of 24 T. sordida eggs 1972; GALVAO & CARVALHO, 1969). T. v. BARRETT et al. 707 abundance of Triatoma sordida (NEIVA, 1914; have occurred in other regions and So~nn dt al. NEIVA & PENNA, 1916; LUTZ & MACHADO, 1915). (1969) give particularly striking examples. Colonization of houses along the Sgo Francisco T. infestans can tolerate high doses of DDT and Rio Grande rivers by Pansrrongylus megistus- (AGOSIN et aZ., 1961) and it is possible that the use a major vector of Chagas’s disease in other areas- of this insecticide for malaria control may have appears to have occurred transiently in the middle favoured T. infestans by selective elimination of of this century. LUTZ & MACHADO (1915) recorded natural enemies of domestic triatomines (BARRETT, P. megistus along the upper reaches of the SBo 1976). In Venezuela, increased infestations of houses Francisco in the State of Minas Gerais (Fig, l), but by following DDT spraying have not downstream in Bahia. ARAGAO et al. (1955) did been reported by BERTI et al. (1961). not find P. megistus along these rivers in an extensive The aualitv of house construction in Barreiro survey of Bahia carried out between 1951 and 1953. Vermelhb was in general much higher than in rural By 1955, P. megistus had become established in areas of endemic Chagas’s disease in eastern Bahia. several areas along these rivers in Bahia (DIAS & None the less, the presence of bug faeces on the SEREBRENICK, 1958) but, by 1971, had been almost upper halves of well-plastered walls was indicative totally replaced there by T. infestans (SHERLOCK & of heavy infestations even in the best houses. SERAFIM, 1972). Apparently T. infestans found adequate refuge along The recorded history of T. infestans in Bahia the tops of the walls or among roof tiles. House appears, at first sight, to be confusing. Because of improvement projects have been proposed as the importance of this species as a vector of Chagas’s fundamental to the successful control of domestic disease, it is worth reviewing the available evidence triatomines (e.g. DE RAADT, 1976), but the coloniza- in some detail. NEIVA (1914), who considered Bahia tion of well constructed houses in Barreiro Vermelho to be among the states of Brazil with the best studied by T. infestans raises the issue of whether such triatomine fauna, gave the distribution of T. measures alone can prevent infestation by this infestans in Brazil as extending from the southern species. state of Rio Grande do Sul as far north as the state of Minas Gerais. Early records of T. infestans from Sources of Trypanosoma cruzi in Riacho de Santana Bahia are of doubtful validity : PINTO (1925) included The high rates of T. cruzi infection observed in T. infestans in the fauna of Bahia but gave no Triatoma infestans and T. sordida in Riacho de reference. He may have been influenced by LUTZ & Santana (Table I) are in contrast to rates of less than MACHADO (1915), who listed T. infestans in the 6”,, recorded in previous surveys in western Bahia appendix of their account of a journey down the (ARAGAO et al., 1955; SHERLOCK & SERAFIM, 1974; river SBo Francisco, but comparison with the main CASTLETON et al., 1974). Moreover, SHERLOCK & text suggests strongly that this name was an error SERAFIM (1974) examined five P. megisrus, 47 T. for T. sordida. ARAGXO et al. (1955) reported T. sordida and 25 T. infestans collected in Riacho de infestans from the north of Bahia, but the identifica- Santana before 1972 and found none to be infected tion of this material has been questioned (ARAG~O with Trypanosoma cruzi. et al., 1964). BUSTAMENTE (1957) recorded T. In areas with stable transmission of T. cruzi, the infertans from Minas Gerais and Goias during proportion of bugs infected increases with the 1950-55, but not from Bahia. DIAS & SEREBRENICK cumulative number of blood meals taken and there- (1958) found T. infestans in Carinhana, on the fore with successive instars (CORREA et al., 1952; southern border of Bahia, but not further- north in COURA & PETANA, 1975; MINTER, 1978; TORRES, the state. Between 1955 and 1964. T. infestans 1915). The fact that a higher proportion of nymphs appeared as far north as the states of Alagoas and than of adults was infected in our samples (Table II) Pernambuco (Fig. 1) (LUCENA, 1959, 1965). suggests an unstable transmission pattern due to a Comparison of the surveys of DIAS & SEREBRENICK rapid increase in the number of infective mammalian (1958) and SHERLOCK & SERAFIM (1972) shows that hosts shortly before the bugs were collected. (The widespread colonization of houses by T. infestans higher infection rates in younger nymphs than in in the SBo Francisco Valley region of Bahia occurred older instars also imply that the early instar nymphs between 1956 and 1971, by which time 23 areas in feed more frequently: this has not been verified Bahia were affected (Fig. 1). At the same time, under natural conditions, but laboratory data-e.g. P. megistus disappeared from the areas colonized by GOODCHILD, 1955 ; SZUMLEWICZ, 1976-suggest T. infestans. In Riacho de Santana this transition that this is likely to be the case.) In particular, occurred in 1964 (I.A.S., unpublished survey Rattus rattus probably became increasingly depend- records). ent on domestic and peridomestic sources of food With the exception of the specimens found by and water following the failure of the maize crop BARRETTO & FERRIOLI FILHO (1964) in sylvatic and the dryness of the woodland caused by the habitats, T. infestans in Brazil has only been found 1975-1976 drought. In this connection, it is of in houses and the peridomestic environment. It is interest to note that in the house with the highest thought to have been dependent on man for its proportion of infected Triatoma infestans, we were distribution, possibly from an original rupicoline shown rat-damaged cotton seed and the route used habitat in the inter-Andean valleys of Bolivia by rats to enter the house from the woodland. We (USINGER et al., 1966). A major factor favouring the found an uninhabited rat nest in the roof of one movement of T. infestans into Bahia during the house and, in other houses, residents said they decade 1955-65 was probably the increasing volume heard rats in the roofs at night. of motorized road traffic between Bahia and the Although we submitted gut contents of the south: passive transport of T. infestans is known to triatomines collected for serological identification of 708 ACUTE CHAGAS'S DISEASE IN BRAZIL: VECTORS AND RESERVOIRS OF T. cruzi the host blood, which would have indicated the da distribuicao geografica dos triatomineos probable sources of Trypanosoma cruzi for the bugs, domiciliarios e seus indices de infeccao natural the results were considered unreliable because of por Schizotrypanum cruzi, no estado da Bahia. incorrect identification of the known control blood Revista Brasileira de Malariologia e Doeqas meals included. However, FREITAS et al. (1960) and Tropicais, 7, 409-42 1. BARRETTO (1968) found that blood meals -from AragPo, M. B. (1964). Correspondencia cientifica. Triatoma sordida and T. infestans from other areas Revista Brasileira de Malariolozia e Doencas reacted with antisera against dog, cat and rodent Tropicais, 16, 420-425. blood. In our study, the high rate of Trypanosoma Barrett, T. V. (1976). Parasites and Predators of cruzi infection in bugs from a rat-infested storage Triatominae. In: New Approaches in American box suggests that R. rattus was a significant source Trypanosomiasis Research. Washington : Pan of T. cruzi for bugs in Riacho de Santana. American Health Organization, Scientific Publica- T. cruzi may have been introduced into the tion No. 318, pp. 24-32. domestic environment in Riacho de Santana with Barretto, M. I?. (1968). Estudos sobre reservatorios infected Triatoma infestans from the south, with e vectores silvestres do Trypanosoma cruzi. human carriers infected in areas of endemic Chagas’s XxX1: Observacdes sobre a associacao entre disease elsewhere or from a local enzootic cycle of reservatorios e vectores, corn especial referencia transmission. The existence of two kinds of T. cruzi, a regiao nordeste do estado de SQo Paulo. Revista distinguishable on the basis of their isoenzymes, Brasileira de Biologia, 28, 481-494. circulating together in the domestic and peri- Barretto, M. I’. & Ferriolli Filho, I’. (1964). Estudos domestic environments of Riacho de Santana sobre reservatorios e vectores silvestres do (BARRETT et al., in press*) suggests that more Trypanosoma cruzi. IV.: Infeccao natural do than one source of parasite contributed to the Triatoma infestans, encontrado em ecotopos outbreak, and the distribution of reservoir hosts and silvestres, por tripanosomo semelhante ao T. vectors observed indicates that domestic, peri- cruzi. Revista do Instituto de Medicina Tropical de domestic and probably sylvatic cycles of trans- .!%a Paula, 6, 219-224. mission are now interlinked. Berti, A. L., Gomez Nunez, J. C., Guerrero, L. & SHERLOCK & SERAFIM (1974) warned that the Martini, G. G. (1961). Estado actual de la en- spread of Triatoma infestans would lead to an fermedad de Chagas en Venezuela. IV. Con- increased prevalence of Chagas’s disease in Bahia, version de la campafia de erradicacion de la even though most specimens examined were not malaria en profilaxis de la enfermedad de Chagas. infected with T. cruzi in most parts of the state at Revista Venezolana de Sanidad y Asistencia that time. The events in Riacho de Santana have Social, 26, 32-40. vindicated this prediction and emphasized once Bustamente, F. M. (1957). DistribuicHo geofrafica again the necessity of energetic measures to combat dos transmissores da doenca de Chagas no Brasil the further spread of T. infestans into north-east e sua relaclo corn certos fatores climaticos. Brazil. Epidemiologia e profilaxia da enfermedade. Acknowledgements Revista Brasileira de Malariologia e Doencas This work was carried out as part of a collabora- Tropic& 9, 191-211. tive programme in Brazil with ihe participation of Castleton, C. W., Martins, R. P. & Viera, J. P. the Nucleo de Pesquisas da Bahia of the Fundacao (1974). Levantamentos de triatomineos domicili- Oswald0 Cruz, the Pan American Health Organiza- ares em Barreiras, Bahia. Revista Goiana de tion, the Federal University of Bahia, the Harvard Medicina, 20, 201-207. School of Public Health and the London School of Correa, R. R., Oliveira, F. de & Carvalho, P. J. Hveiene and Trouical Medicine. In Riacho de (1952). Da infeccao natural pelo Trypanosoma Saltana. we were kindlv assisted by the local unit cruzi das ninfas e adultos do Triatoma infestans of the Superintendencia de Camp&has de Satide (Hemiptera, Reduviidae). Arquivos de Higiene e Publica (SUCAM). bv Mavor Dr. Togo Batista Dias Saude Publica, 17, 9-14. Laranieiras, Dr. ‘Nilion Cardoso”Fernandez, and Coura, J. R. &-Pet&a, W. B. (1975). Additional data on the euidemioloev of Chaeas’ disease in members of the municipal staff. We were supported Y’ in the field bv Sr. Tome Silva de Oliveira and in the the municipahty of Caxias, Rio de Janeiro state, laboratory by Srta. Vera Lucia Menezes. This Brazil. Revista da Sociedade Brasileira de Medicina project was supported financially by the Wellcome Tropical, 9, 83-87. Trust, the Pan American Health Organization and Dias. E. & Serebrenick. S. (1958). Aspectos Indtistria e Comercio de MineracBo, S.A. (ICOMI). climaticos da distribuicao dos ‘transmissores da Doenca de Chaeas no Vale do Rio Silo Francisco. References Memo&as do Institute Oszoaldo Cruz, 56, 407-414. Agosin, M., Scaramelli, N. & Neghme, A. (1961). Freitas, J. L. Pde, Siquiera, A. F. de & Ferreira, Intermediary carbohydrate metabolism of Tria- 0. A. (1960). Investigacdes epidemiologicas sobre toma infestans (Insecta: Hemioteral. I. Glvcolvtic triatomineos de habitos domesticos e silvestres and pentose phosphate pathway’ enzymes and corn auxilio do reacao de precipitina. Revista do the effect of DDT. Comaarative Biochemistry and Instituto de Medicina Tropical de SZo Paula, 2, Phvsiologv, 2, 143-159. * 90-99. Aragio, J.--M. B., Aguirre, G. H., Leal, J. M. & GalvHo, A. B. & Carvalho, A. L. de M. (1969). Serafim. E. (1955). ContribuicHo ao conhecimento Triaroma maculata (Erickson, 1848) uma especie ocorrente em Goias. Revista Brasileira de Malario- * Trans. R. Sac. trap. Med. Hyg., 74 (1). logia e Doeqas Tropicais, 21, 830-832 T. v. BARRETT et al. 709

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