sign in sign up
<<
Home , Lutzomyia, Lutzomyia longipalpis, Phlebotominae, Sandfly

Medicai and Veterinary Eníomology (1992) 6, 195-2(K)

Host preferences of the phiebotomine longipalpis in Amazonian

R. J. QUINNELL, C. DYE and J. J. SHAW* Department of Medicai Parasitology, London School of Hygiene and Tropical Medicine, and *Wellconie Parasitology Unií, Instituto Evandro Chagas, CP. 3, Belém, 66001 Pará, Brazil

Abstract. Experiments were undertaken to determine the relative attractiveness of , and to , the principal of chagasi causing American visceral . Field experiments in two villages on Marajó Island, Pará State, Brazil, showed that one boy at- tracted significantly more than one or , and slightly fewer flies than a group of six chickens. Experiments with laboratory-bred female flies showed that a significantly greater number of flies engorged on a single than on either a single dog or chicken, and man-biting catches demonstrated the willingness of flies to bite in the field. It appears that Lu.longipalpis has catholic feeding habits, the attractiveness of different hosts being largely a function of their relative sizes. These results are discussed with reference to the epidemiology of in Brazil.

Key words. Lutzomyia longipalpis, , sandfly, preference, visceral leishmaniasis, Leishmania chagasi, Amazónia, Brazil.

Introduction also been found in smaller numbers in some forest áreas (Lainson et al., 1990). Despite its abundance, very little is The phiebotomine sandfly Lutzomyia longipalpis Lutz known of its innate host preferences or its actual biting be- & Neiva (Diptera: ) is the most important haviour. In northeast Brazil, e.g. Ceará State, Lu.longi• vector of American visceral leishmaniasis (AVL), caused palpis is considered to be anthropophilic, readily biting by Leishmania chagasi Cunha & Chagas (Lainson et ah, man (Deane & Deane, 1962; Ward et al., 1983). Deane 1977; Lewis & Ward, 1987). In most áreas it is the only (1956) captured more flies on people than on dogs, although known vector, although Lu.evansi is an alternate vector in the largest numbers were caught on donkeys, and up to Colômbia (Travi et al., 1990). 2608 Lu.longipalpis females have been captured inside a Although AVL occurs from México to single house (Deane & Deane, 1962). In Costa Rica, (Grimaldi et al., 1989), over 90% of human cases come Zeledon et al. (1984) captured similar numbers of flies from Brazil. Within Brazil there are large regional dif- on people, dogs, , and cattle. By contrast, ferences: of 9295 cases reported during 1983-88, 8740 in Amazonian Brazil, casual observations suggest "that were from the northeast and only 193 from the Amazon Lu.longipalpis is 'not particularly anthropophilic, and region (Vieira et al., 1990). AVL is thought to be largely much more inclined to feed on dogs' (Lainson & Shaw, zoonotic, the most important reservoir hosts being the 1979). In Rio de Janiero State, Aguiar e/a/. (1987) captured domestic dog and various wiid canids, especially Cerdocyon more flies on chickens than either people or dogs. Corredor thous (L.) (Deane, 1956; Lainson etal., 1990). Prevalence et al. (1989) made night biting collections in Colômbia and of is generally greater in dogs than in humans 'observed repeatedly that [Lu.longipalpis] prefer to feed (Deane, 1961), although few surveyshave used comparable on domestic animais, including poultry, if these animais techniques in both populations. are available.' In Brazil Lu.longipalpis is often abundant peridomesti- None of these studies amount to definitive field exper• cally, especially in pens (Deane, 1956). It has iments on host choice by Lu.longipalpis females resolving the questions of (1) whether or not they have host pre• Corrcspondcnce: DrC. Dyc, Vector Biology and Epidemiology ferences, either innate or facultative; if so (2) whether host Unit. Department of Medicai Parasitology. London School of preferences vary from one population to another. Such Hygiene and Tropical Medicine, Keppel Street. London WCIE variation might be expected, as Lu.longipalpis, sensu lato, 7HT, U.K. is known to exist as a complex of at least two .

195 196 R. J. Quinnell, C. Dye and J. J. Shaw which are reproductively isolated froni each other and different host individuais, except that only one dog was which produce different compounds (Ward used in ali four replicates at Albino. Hosts were rotated et al., 1983, 1988). Both species occur in NE and S Brazii, between chicken sheds each night (position 1 i'. 2), such whiie only one occurs in the Amazon region, and it has that a different host species was present in any one chicken been suggested that interspecific differences in the degree shed each night. of anthropophily may help explain the distribution of At the end of each replicate the number, sex and species human AVL disease in Brazil (Ward et al., 1983, 1985). of ali trapped was recorded. Male and female In this paper we focus on question (1) above, reporting Lu.loiigipalpis were routinely identified from externai the results of a series of experiments designed to deter• morphology; doubtful females were dissected and sper- mine the innate host preferences of Lu.longpalpis on mathecae examined. Marajó Island in Amazonian Brazil. Three host species Experiment 2. This experiment compared the attract• were used: humans, dogs and chickens, the iatter being iveness of a boy and a group of chickens; only two chicken the most abundant domestic animal in the region. The sheds at each site were used. The boy was in one shed and work is the first step towards explaining why, on Marajó chickens were in the other, either twelve (Campinas) or six Island, seroprevalence of AVL in the human population to seven (Albino). Experimental details were otherwise is very much lower (<2%) than it is in the dog population unchanged. Experiments were repeated six times at (around 50%: unpublished data, Wellcome Parasitology Campinas (using three different boys) and four times at Unit, Belém). Albino (two different boys), the position of the hosts being swapped in each replicate. Human-biting catches. These were carried out at the Materials and Methods Campinas house. R.J.Q. and J.J.S. sat 4m from the main chicken shed for 1 h between 18.40 and 20.40 hours on Study area. Field experiments were carried out in two three consecutive nights in May 1991. Ali biting female viilages (Campinas and Albino) in Salvaterra district, fiies were collected at the time of biting; at the end of the Marajó Island, Pará State, Brazil (0°46'S, 48°31'W). hour as many settled male flies as possible were also col• This is an area of savannah and open woodiand, with oc- lected. On the first night only, ali chickens were removed casional patches of seasonally flooded forest. The human from the chicken shed beforehand. population consists mostiy of farmers; pineappics are an Laboratory experiment (Experiment 3). This experiment important cash crop. Houses are usually constructcd of used first generation laboratory bred Lu.longipalpix from mud on a wooden frame, with a palm-thatched roof. Most a colony at the Wellcome Parasitology Unit, Belém, which houses also have a chicken shed nearby, made of wooden had been established with wild-caught female flies from stakes driven into the ground, with a paim roof. Houses Marajó. Flies used were ali females, 1-7 days old, and generally have one or more dogs; and pigs are also had been offered solution only. present in smaller numbers. Laboratory experiments were Single humans, dogs or chickens were placed in pairs carried out in Salvaterra town. Ali experiments were 1.5 m apart inside a large, sandfly-proof net sized 2 x 1.4 x carried out between April and December 1991. 1.4m. Dogs and chickens were constrained in metal cages. Field experiments. These were carried out in the back- Ali humans were adult males aged 25-45 years. Fifteen yards of two houses, one each in Campinas and Albino. to fifty-three female flies were then released into the net At each site, four new chicken sheds were constructed, and recaptured after Ih. Five replicates of each host each 1 X 1 X 1.5 m. The sides and raised floor of the sheds combination were carried out, on different days and using were made of 2 x 1 cm timber; the roof was thatched with different host individuais. Ali experiments were carried palm leaves. The sheds were placed in a semi-circular out between 20.00 and 23.30 hours. arrangement, 4m from the existing chicken shed, and 4m Engorged flies were squashed onto a glass microscopc (Campinas) or 6m (Albino) from each other. slide (chicken versus man/dog comparisons) or blotted Experiment I. This experiment was designed to test the onto filter paper (man versus dog comparisons). Slides relative attractiveness of three host species: human, dog were stained with Giemsa and examined under 400x and chicken. Hosts were borrowed from nearby houses magnification for the presence of nucleated erythrocytes. with the consent of their parents or owners, and were Filter papcrs were stored at room temperature in plastic protected with sandfiy-proof netting during the experiment. bags containing desiccant and transported to the U.K. Ali human participants were 9-15-year-old boys. Scra were then eluted and the bloodmeal identified by At the start of the experiment (between 18.(K) and ELISA using standard techniques (Service et al., 1986). 19.30 hours) an individual of each host species was placed in each chicken shed; the fourth shed was left empty. A CDC miniature light-suction trap was placed in the Results apex of each shed, and the resident chickens removed Experiment l from the original chicken shed (except for one brooding hen). The sheds were then left undisturbed, with no other A total of 1270 Lii.longipalpis were captured; seven hosts nearby, for 3-4.5 h. Four replicates were carried sandflies of other species were also captured but have out at each house, not on consecutive nights: each used been excluded from the analysis. Host preferences of Lutzomyia longipalpis 197 At both sites the majority of flies were attracted by sites were not significantly different from unity (Campinas, humans (Table 1). Analysis of variance (ANOVA) on X- = 2.34, df=l, n.s.; Albino, x"=l-44, df=l, n.s.). logarithmically transformed data, taking out the effects However, in two of four experiments there were significant of night and position, revealed significant differences differences in sex ratio between hosts (Experiment 1 at between the attractiveness of different host species at Campinas: x" = 36.3, df = 3, P < 0.(X)1, and Experiment 2 Campinas (Table 2), where humans attracted significantly at Albino: x- = 35.(), df = 1, P<0.0()1); in both cases the more flies than the no-host control and more flies than either sex ratio of flies attracted by humans was less male-biased dogs or chickens: human versus dog, / = 8.32 (females) (Table 5). In the other two experiments there were no or í=5.45 (males + females), df = 6, P<().()l). Differ• significant differences. ences between the numbers of flies on dogs, chickens and the no-host control were not significant. There was no significant difference at Albino, although differences were Human-biting catches in the same direction as those at Campinas (Tables I and 2). Totais of 121 (61 males, 60 females), O and 139 (111 males, 28 females) sandflies were captured each night; ali Experiment 2 were identified as Lu.longipalpis. Male flies were mostiy distributed on the upper back, and appeared to be in Of 1285 sandflies captured, 1280 were identified as mating swarms (cf. Lane et al., 1990). Lu.longipalpis. The nuniber of flies attracted by a boy was slightly less than that attracted by six to seven or twelve chickens, although these differences were not Experiment 3 significant at either site (Tables 3 and 4). Overall sex ratios of Lu.longipalpis captured at both In total, 334 out of 463 flies (72%) -fed during the

Table 1. Numbers of Lu.longipalpis attracted to a single human, dog or chicken (Experiment 1): m, males; f, females; m -^ f, ali flies on cach night; the gcomctric mean total number (SE range) of flies over four nights, and the ratios of treatment means. Host Human Dog Chicken None Site Night m f m + í m f m-l-f m f m-t-f m f m + f Campinas 1 45 38 82 26 6 32 0 0 0 0 0 0 2 32 67 99 2 1 3 4 2 6 3 2 5 3 141 141 282 5 5 10 3 1 4 3 1 4 4 43 57 100 9 1 10 14 5 19 16 1 17 Mean 123 (93-163) 10 (6-16) 4 (2-9) 4 (2-8) Ratio 31 2.5 1 1 Albino 1 70 86 156 13 23 36 2 4 6 4 4 8 2 23 19 42 20 33 53 8 10 18 3 6 9 3 27 48 75 16 10 26 3 6 9 7 17 24 4 22 21 43 29 13 42 34 19 53 5 7 12 Mean 68 (50-92) 38 (33--44) 15 (9--24) 12 (9--15) Ratio 5.7 3.2 1.25 1

Table 2. Factors affecting the numbers of Lu.longipalpis caught in chicken sheds containing hosts of different species (ANOVA, Experiment 1). Females Males -t- females Site Factor d.f. F P F P Campinas Night -t- position 6, 6 2.05 n.s. 4.16 n.s. Host 3, 6 44.52 <0.001 23.85 <0.001 Albino Night + position 6, 6 0.24 n.s. 0.15 n.s. Host 3, 6 3..33 n.s. 3.74 n.s. 198 R. J. Quinnell, C. Dye and J. J. Shaw

Table 3. Numbcrs of Lu.longipalpis attraclcd hy a singic human or groups of chickcns (Expcrimcnt 2): m, males; f, femalcs: m + f. total number of flies on each night; thc gcomctric mean total numbcr (SE range) of flies, and the ratios of treatment means. Host 12 chickcns (Campinas) 1 human 6-7 chickcns (Albino) Site Night Position m f m + f m f m + f Campinas 1 1 44 38 82 36 33 69 2 2 11 11 22 34 13 47 3 1 1 1 2 2 2 4 4 2 9 6 15 29 96 125 5 1 21 36 57 5 3 8 6 2 51 56 107 52 74 126 Mean 26 (14-48) 34 (19--62) Ratio 0.76 1 Albino 1 1 6 5 11 32 18 50 2 2 8 2 10 5 7 12 3 1 58 29 87 115 36 151 4 2 93 153 246 32 17 49 Mcan 39 (18- 86) 46(27--77) Ratio 0.85 1

Table 4. Factors affecting the numbcrs of Lu.longipalpis attracted Table 5. Mean sex ratio (males/total) of Lu.longipalpis attracted by a singic human or groups of chickcns (ANOVA, Expcrimcnt 2). by diffcrcnt hosts. Femalcs Males -t- femalcs Site Site Factor d.f. F P F P Campinas Albino Campinas Night + position 6, 4 2.61 n.s. 4.34 n.s. Expcrimcnt I Host 1,4 0.10 n.s. 0.28 n.s. Boy 0.463 0.449 Albino Night + position 4, 2 1.45 n.s. 4.64 n.s. Dog 0.764 0.497 Chicken 0.724 0.547 Host 1,2 0.004 n.s. 0.08 n.s. Nothing 0.846 0.358 Expcrimcnt 2 experiment (Table 6). Men were significantly preferred Boy 0.481 0.466 to both dogs and chicken — the expected percentage with Chickcns 0.417 0.702 no choice (50%) being outside the 95% confidence limits in both cases. There was no overall preference for dogs over chickens, although there was apparently some pre• These results are similar to those obtained by Deane ference within replicates. (1956) in Ceará, who compared the number of flies feeding on individual domestic animais. Donkeys, cows and horses attracted most flies, followed by humans, dogs and chickens Discussion in that order. Deane (1956) also noted that the sex ratio of flies attracted by humans was more female-biased than The results presented here show that Lu.longipalpis on other hosts. In contrast, Aguiar et al. (1987) found females do not have strong innate host preferences on that a single chicken attracted about 10 times as many Marajó Island. The attractiveness of the three host species Lu.longipalpis as a single human, dog or donkey. Un- studied seemed to be largely a function of host size: a fortunately, both studies involved capturing flies by hand, single boy attracted a number of flies intermediate between so the proximity of the collector to the hosts may have that attracted by one and six to seven chickens. In these influenced their attractiveness. Additionally, few details íield experiments flies were prevented from biting hosts, of experimental design are given. so it is unclear vvhether but results of the laboratory experiments showed that flies possible confounding variables such as the position of the blood-fed on ali three host species, a single human again host or variation between different individuais of the same attracting more flies than either a dog or a chicken. host species were controlled for. Hosi preferences of Luizomyia longipalpis 199

Table 6. Numbcrs of fcmale Lu.longipalpis fccding on humans, attracted to a similar extent by dogs, goats and rats, although dogsorchickens (Expcriment 3). Columns labcllcd Both' includo in both cases chickens attracted the greatest number. In flics whosc bloodmcals wcrc unidcmificd. the three studies quoted above, the statistical significance of results is unclear. An alternative approach was taken (1) Dog versus chickcn by Rioux & Golvan (1969), who compared the proportion of female P.ariasi Tonnoir feeding on various species of Trial No. Fcd Dog Chieken Boih % Dog and in the laboratory: a high percentage fed on dogs, chickens and foxes, but flies did not feed 1 43 2 1 1 0 50.0 2 36 33 9 24 0 27.3 on . 3 48 45 30 7 8 81.1 The results presented in this paper show that the relative 4 53 49 21 23 5 47.7 rarity of cases of human visceral leishmaniasis (AVL) in 5 45 27 26 1 0 96.3 Amazonian Brazil cannot be explained in terms of innate vector host preference. However, the willingness of the 95% c.i. (or% feeding oii dog; (MA ± 34.5. vector to bitc humans in these experiments does not mean that humans are frequently bitten in the field, where host (2) Human versus ehickcn accessibility will also be important. The man-biting catches show that people certainly can receive a large number of Trial No. Fcd Human Chickcn Both % Human bites whiist outside houses, but it is possible that Lu.longi- pulpis is essentially exophagic and rarely comes into contact 1 27 16 15 1 0 93.8 2 15 14 13 1 0 92.9 with humans when feeding at night. Future experiments 3 18 15 15 0 0 100.0 will address this question. 4 33 11 9 2 0 81.8 The question of whether there are differences in the 5 20 10 5 4 1 55.6 behaviour of populations of Lu.longipalpis, sensu lato, from Amazonian and northeast Brazil remains open. The 95% c.i. lor % fccding on man; 84.4 - 15.4. similarity between the results presented here and those of Deane (1956) suggests that flies in the two áreas are (3) Human versus dog similarly anthropophilic, although there could be other behavioural differences. Other factors are also likely to be Trial No. Fcd Human Dog Both % Human important in determining the incidence of visceral leish• 1 21 19 16 3 0 84.2 maniasis in the two áreas, such as differences in house con- 2 17 17 11 6 0 64.7 struction or the nutritional status of the human population. 3 22 22 10 7 5 58.8 4 41 29 18 8 3 69.2 5 24 22 14 7 1 66.7 Acknowledgments

95% c.i. for fccding on man: 68.7 ±8.3. We thank Augusto Francisco Nascimento Filho, João Batista Palheta da Luz, Nagib Fernandes and Jorge Carvalho for technical assistance in the field and Nigel It is also not known which member of the Lu.longipalpis Hill for help with the ELISA. Professor R. Lainson and (sensu Ward et al., 1988) was present In Dr J. Travassos da Rosa kindly provided facilities at the either of these two áreas, and the disparity between the Instituto Evandro Chagas, and Dr P. Ready made helpful results may thus reflect interspecific differences. suggestions on the manuscript. The work was funded by Investigations into the host-feeding patterns of other the Wellcome Trust. species of phiebotomine sandfiies have mostly used blood- meal analysis; few controlled experiments have been carried out on innate host preferences. Christensen & References Herrer (1980) examined the relative attractiveness of caged individuais of various species of , , Aguiar, G.M. de, Vilela, M.L. & Lima, RB. (1987) Ecology of and amphibian (but not humans) to sandfiies in the sandfiies of Itaguai, an area of Panamá: of the four common sandfiy species one showed a in the State of Rio de Janeiro. Food preferences (Diptera, distinct preference for , the other three were attracted Psychodidae, Phiebotominae). Memorias do Insiilulo Oswaldo Cruz, 82, 583-584. by a wider range of hosts, including birds, but showed a Christensen, HA. & Hcrrcr, A. (1980) Panamanian'Lurzomyúr preference for rodents. Host size did not seem to be (Diptera: Psychodidae) host attraction profiles. Journal of importam, as smaller rodents and bats attracted more flies Medicai Enlomology, 17, 522-528. than larger primates and carnivores. Similarly, Shaw & Corredor, A., Gallego, J.F., Tesh, R.B., Morales, A., de Carras- Lainson (1968) found that Lu.jlaviscutellaia (Mangabeira) quilla, C.F., Young, D.G., Kreutzcr, R.D., Boshell, J., Palau, exhibited a marked preference for rodents over humans. M.T., Caceres, E. & Pelaez, D. (1989) Epidcmiology of visceral Experiments carried out by Mutinga cí ul. (1986) in Kenya leishmaniasis in Colômbia. American Journal of Tropical showed that the two species of Fhlebotoinus present were Medicine and Hygiene, 40, 480-486. 2(K) R. J. Quinnell. C. Dyc and J. ./. Show

Dcaiic. L.M. (1956) Leishmaniose Visceral no Hra.sil. Estudos Rioux. J. A. íí (iolvan, Y.-J. (1969) Epidemiologie des Leish- sobre Reservatórios c Transmissores Realizados no Estado do manioses dans le Stid de la Trance. Monograph 37. INSRM. Ceará. Serviço Nacional do Educação Sanitária. Rio de .laneiro. Paris. Deane, L.M. (1961) Reservatórios da Leishtnania donovani no Service. M.W.. Voller. A. & Bidwcll. DE. (1986) The enzyme- Brasil. Revista da Associadade Medicina Brasileira. 7. 161 - 169. linked immunosorbent assay (ELISA) test for lhe idcntification Deane. L.M. & Deane, M.P. (1962) Visceral leishmaniasis iii of blood meais of hacmalophagous . Bulletin of Ento- Brazil: geographical distribution and . Revista do mological Research. 76. .321-3.30. Instituto de Medicina Tropical São Paido. 4, 198-212. Shaw. J.J. & Lainson. R. (1968) Leishmaniasis in Brazil. II Grimaldi, G., Tcsh, R.B. & McMalion-Pratt. D. (1989) A review Obscrvations on enzootic rodcnt leishmaniasis in the lower of thc geographic distribution and epidemiology of leishmaniasis Amazon region - thc feeding habits of thc vector, Lutzomyia in the . American Journal of Tropical Medicine and jlaviscutellata in refcrence to man, rodents and othcr animais. Hygiene. 41, 687-72.5. Transaclions of the Royai Sociely of Tropical Medicine and Lainson, R. (1985) Our present knowledgc of the ecology and Hygiene. 62. .396-405. control of leishmaniasis in thc Amazon region of Brazil. Revista Travi, B.L., Velez, I.D., Brutus, L., Segura. L, Jaramillo, CD. da Sociedade Brasileira de Medicina Tropical, 18, 47-56. & Montoya, J. (1990) Lutzomyia cvansi. an altcrnate vector of Lainson, R., Dye, C, Shaw, J.J., Macdonald, D.W., Courtenay, Leishmania chagasi in a Colombian focus of visceral leish• D.O., Souza, A.A.A. & Silveira, F.T. (1990) Amazonian maniasis. Transactions of the Royai Society of Tropical Medicine visceral leishmaniasis - distribution of the vector Lutzomyia and Hygiene. 84, 676-677. longipalpis (Lutz & Neiva) in relation to the fox Cerdocyon Vieira, J.B., Lacerda, MM. & Marsden, P.D. (1990) National lhous (Linn.) and the cfficiency of this reservoir host as a source reporting of leishmaniasis: the Brazilian cxperience. 1'ara- of infection. Memorias do Instituto Oswaldo Cruz, 85. 135-1.'?7. sitology Today. 6. 339-340. Lainson, R. & Shaw, J.J. (1979) The role of animais in thc Ward. R.D., Phillips. A.. Burnct. B. & Marcondes, C.B. (1988) epidemiology of South American leishmaniasis. Biology oj the The Lutzomyia longipalpis complex: reproduction and dis• Kinetoplastida. Vol. II (ed. by W. H. R. Lumsden and D. A. tribution. Biosvstemutics of Haematophagous Insects (cd. by Evans), pp. 1-116. Academic Press, London. M. W. Service), pp. 257-269. Clarendon Press, Oxford. Lainson, R., Ward, R.D. & Shaw, J.J. (1977) Experimental Ward. R.D.. Ribeiro, A.L., Ready. PD. & Murtagh. A. (1983) transmission of Leishmania chagasi, causative agcnt of neo• Reproductivc isolation betwecn different forms of Lutzomyia tropical visceral leishmaniasis. by the sandfly Lutzomyia longi• longipalpis (Lutz & Neiva) (Diptcra: Psychodidae), the vector palpis. Nature, 266, 628-630. of chagasi Cunha & Chagas and its signi- Lane, R.P., Pile, M.M. & Amerasinghe, F.P. (1990) Anthro- ficance to kala-azar distribution in . Memorias pophagy and aggregation bchaviourof the sandfly Phlehotomus do Instituto Oswaldo Cruz. 78. 269-280. argentipes in Sri Lanka. Medicai and Veterinarv Entomologv. Ward. R.D., Ribeiro, A.L.. Ryan. L., Falcão, AL. & Rangel, 4, 79-88. E.F. (1985) The distribution of two morphological forms of Lewis, D.J. & Ward, RD. (1987) Transmission and vcctors. The Lutzomyia longipalpis (Lutz & Neiva) (Diptcra: Psychodidae). Lei.shmaniases in Biology and Medicine (cd. by W. Peters Memorias do Instituto Oswaldo Cruz. 80. 145-148. and R. Killick-Kendrick), pp. 235-262. Academic Press, Zpledon. R.. Murillo, J. & Gutierrez. H. (1984) Obscrvaciones London. sobre la ecologia de Lutzomyia longipalpis (Lutz & Neiva, Mutinga, M.J.. Kyai, F.M., Kamau. C. & Oníogo. DM. (1986) 1912) y posibilidades de existência de leishmaniasis visceral en Epidemiology of leishmaniasis in Kenya. III. Host prcfercnce Costa Rica. Memorias do Instituto Oswaldo Cruz, 79, 455-459. studics using various types of animal baits al animal burrows in Marigat, Baringo District. In.sect Science and its Application, Accepted 21 April 1992 7. 191-197.