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Memórias do Instituto Oswaldo Cruz
Fundação Oswaldo Cruz, Fiocruz
ISSN: 1678-8060 EISSN: 1678-8060
Vol. 94, Num. 1, 1999, pp. 11
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oc99005
Mem Inst Oswaldo Cruz, Rio de Janeiro, 1999
Vol. 94(1): 11
RESEARCH NOTE
Natural Infection of Lutzomyia rangeliana (Ortiz, 1952) (Diptera:
Psychodidae) with Leishmania in Barquisimeto, Lara State, Venezuela
R Bonfante-Garrido+, R Urdaneta, I Urdaneta, J Alvarado, R
Perdomo
Universidad Centroccidental "Lisandro Alvarado", Decanato de Medicina, Departamento
de Medicina Preventiva y Social, Unidad de Investigación en Parasitología
Médica, Barquisimeto, Venezuela
+Corresponding author. Fax: +58-51-591894
Received 19 June 1998; Accepted 2 October 1998
Code Number:OC99005
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RESEARCH NOTE
Key words: cutaneous leishmaniasis - Lutzomyia rangeliana - Leishmania
venezuelensis - Venezuela
Cutaneous leishmaniasis caused by Leishmania venezuelensis (Bonfante-Garrido,
1980) is endemic in dry urban areas in the central part of western Venezuela (R
Bonfante-Garrido et al. 1992 Trans R Soc Trop Med Hyg 86: 141-148). This
disease has been also found in cats (R Bonfante-Garrido et al. 1996 Rev Cient Fac Cienc
Veter Univ Zulia Venezuela 3: 187-190). Lutzomyia olmeca
bicolor (Fairchild & Theodor, 1971) formerly suspected as a vector of L.
venezuelensis could not be found in dry urban areas where most of the cases of cutaneous
leishmaniasis occurs. Lu. trini-dadensis (Newstead, 1922) had been found
infected with promastigotes, but isolates could not be maintained in culture media and into
hamsters and, therefore, were not characterized(R Bonfante-Garrido et al. 1990 Mem
Inst Oswaldo Cruz 85: 477). In October 1997, L. venezuelensis was
isolated from two patients, father and son, with ulcerous lesions on the skin, one of them on
the right shoulder and the other, on the left arm and chest. They lived at El Tostao, a
peripheral sector of Barquisimeto city, in a house made of blocks, with a yard of about 800
m2, with several trees and bushes. An entomological study was started in this
house, on 12 November 1997. To date, 31 captures have been made, between 19 and 22 hr,
using Shannon and CDC light traps, in the yard and in the bedrooms. We collected and
examined for natural infection with flagellates 1,001 female sand flies. All of them were
identified by examining their genitalia. Five species were found: Lu. cayennensis
(Floch & Abonnenc, 1945) 337, Lu. rangeliana (Ortíz, 1952)
293, Lu. atroclavata (Knab, 1913) 278, Lu. trinidadensis 184 and Lu.
dubitans (Sherlock, 1962) 9. Except for Lu. rangeliana, which is moderatly
anthropophilic, all are considered to feed preferentially on rodents and reptiles (I Ortíz
1968 Derm Venez 7: 530-538). Females were individually dissected following the PT
Johnson et al. technique (1963 Exp Parasitol 14: 107-122); when infected with
promastigotes, the intestinal tract was examined to observe their location, then it was picked
up from the slide and carefully disrupted in 0.5 ml of steril 0.9% sodium chloride solution. 0.1
ml of the suspension was inoculated into the footpad of hamsters. These animals were weekly
examined for lesions. We found 23 (7.8%) Lu. rangeliana positive for flagellates. In 9
of these specimens fastly moving promas-tigotes were found in the midgut; in 2 they were in
the foregut, midgut and pylorus; in 8, in the midgut and pylorus; in 1, only in the pylorus; in 1,
in the midgut, pylorus and the rectal ampullae; and in 2, in the foregut, pylorus, rectal
ampullae and Malpighian tubules. In 1 (0.3%) Lu. cayennensis flagellates were found
in the pylorus, but the parasite has not yet been isolated. In hamsters, 17 isolates from Lu.
rangeliana caused a tumor-like inflamation at the inoculation site, with histiocytes
containing large number of amastigotes; after two months metastases were observed on limbs,
nose, ears and tail. Other 12 hamsters inoculated with 6 of these isolates are still in
observation. The strains isolated are morphologically and biologically very similar to L.
venezuelensis. The source of these infection is probably a common rodent. Species
identification of parasites isolated from Lu. rangeliana, by molecular techniques, is
already in progress.
Financed by the CDCHT, Universidad Centroccidental "Lisandro Alvarado", Venezuela.
Copyright 1999 Fundacao Oswaldo Cruz - Fiocruz
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