Eco-epidemiology of visceral leishmaniasis in Argentina

SALOMÓN OD, ACARDI, SA, ROSA JR, QUINTANA MG

Lima, Peru

Simposio; ISOPS-". 6th International Symposium On Phlebotomine Sandflies; 2008

From 1925 to 1989 14 cases of leishmaniasis with visceral involvement were reported from Argentina. They were sparsed through the area of cutaneous leishmaniasis, without records of Lutzomyia longipalpis or other Leishmania chagasi known vectors. Lu. longipalpis were reported in 1953 (Candelaria) and in 2000 (Corpus) in the northeastern province of Misiones, without visceral leishmaniaisis (VL). Since the reports of Lu. longipalpis-VL in Campo Grande (Brazil) and Asunción (Paraguay), phlebotomine surveillance was intensified in the northern border of Argentina. Lu. longipalpis was found in Clorinda (Formosa province) on the border with Asunción in 12/2004. The city was screened again for phlebotomine in 11/2007, with traps in 140 peridomestic sites. Lu. longipalpis was found in 7 sites (n=51), in the two neighbours already positive in 2004. Canine VL, but not human VL, is spreading all over Clorinda despite the Lu. longipalpis clustered distribution. Infected dogs came also through the border.   The first human autochtonous case, with concurrent canine VL and Lu. longipalpis, was recorded during 5/2006 in Posadas (Misiones province). Lu. longipalpis (n=5064) was found in 42% of the 314 sites sampled (‘worst scenario’ in 400 x 400 mts, 2-3/2007), but only 5,2% of these sites had more than 31 Lu.longipalpis/trap. No spatial clustering of positive traps were found. L. infantum chagasi was typified from human and dogs. Up to 5/2008 VL was reported in 19 humans (3 dead), and estimated in 3500 dogs. La Banda (Santiago del Estero province) reported 4 human VL cases and 8 dogs with VL (screening around the cases) from 10/2007 to 5/2008. All the cases were in an area of 1.5 km2. The focus was sampled in 11/2007 and 4/2008 (134 Lu. migonei, 14 Lu. cortelezzii, 2 Lu. neivai) with 15-21 traps up to 250 mt from each case. The human case, the dogs and the highest abundance of Lu. migonei were concurrent (10 m). L. chagasi was typified from VL human cases. The role of Lu. migonei as a permissive vector of VL is under research.