Isolation of Leishmania infantum from symptomatic and asymptomatic cases of canine leishmaniasis of Argentina

LOCATELLI FM; BARROSO PA; MARCO JD; RUYBAL P; MORA MC; HOYOS CL; UNCOS AD; CARDOZO RM; GENTILE AG; NEVOT MC; ESTÉVEZ JO; BASOMBRÍO MA; HASHIGUCHI Y; KORENAGA M

Kobe

Congreso; 12th Asian - Pacific Congress for Parasitic Zoonoses; 2012

Leishmaniasis is a zoonotic disease, caused by kinetoplastid flagellates of the genus Leishmania, the visceral form is the severest one and it is fatal if not treated appropriately. Visceral leishmaniasis (VL) is found across South America, where the main causal agent is Leishmania (L.) infantum (= L. (L.) chagasi), and dogs are the main domestic reservoir. In Argentina, VL has recently emerged, although not defined in detail. According to clinical signs, infected dogs are divided into three categories: those with more than three clinical symptoms are Symptomatic, Oligosymptomatic are those from one to three clinical symptoms and Asymptomatic. Parasitological diagnostic methods, based on observation of amastigotes, are very specific but lack of sensitivity. Contrary to this, serological methods, such as rK39, have good sensitivity but lack of specificity. The isolation of promastigotes in vitro culture is the only method able to prove infection with alive, viable and transmissible parasites and it is necessary for applying characterization by biochemical or molecular methods. We examined symptomatic and asymptomatic dogs from Misiones and Salta provinces. Spleen and lymph node aspirates were taken for culture in USAMARU medium with PBSS. Eleven Leishmania stocks (seven from Misiones and four from Salta endemic areas) were isolated from eight asymptomatic and symptomatic dogs and were typified by PCR and Cytochrome b gene sequencing as L. (L.) infantum. We found two genotypes LiA1 and LiA2. This is the first report of the isolation of L. (L.) infantum from Argentinean canine leishmaniasis cases. The parasite/strain isolation from symptomatic and asymptomatic dogs would mean that both may play an important role in the L. (L.) infantum transmission cycles, although symptomatic and asymptomatic dogs would have different force of infection rates in the given endemic areas.