Inter-relation of sylvatic and domestic transmission of Trypanosoma cruzi in areas with and without domestic vectorial transmission in Minas Gerais, Brazil

During the period 1980-1986, we captured triatomine bugs and mammalian reservoir hosts from sylvatic and domestic situations in different municipalities of the State of Minas Gerais. Trypanosoma cruzi was isolated from captured bugs, mammals and patients. After cultivation in LIT medium, the electrophoretic enzyme profiles were determined. We obtained a total of 32 parasite isolates from regions with active domestic transmission, and 24 isolates from areas under control. For the first areas the results suggest introduction of T. cruzi from sylvatic habitats, through incursion of infected opossums and/or sylvatic T. sordida, which appears to have given rise to at least one acute human infection. Of particular interest is the finding of sylvatic opossums and a T. sordida nymph infected with ZB, that could indicate return of parasites from chronic human infections to sylvatic transmission cycles. For the areas under control we also interpret the results as interaction between sylvatic and domestic cycles of transmission, here through the invasion of houses by bugs carrying the Z1 zymodeme from the sylvatic environment. The Multivariate Correspondence Analysis gives a spatial description between the different parasite isolates and confirms the existence of a bridge in the opposite direction in the region with active vectorial transmission including the exporting of Z2 through the peridomestic environment into the sylvatic cycle. For the other areas this bridge corresponds especially to Panstrongylus megistus, importing Z1 into the domestic environment

Clinical risk factors for therapeutic failure in kala-azar patients treated with pentavalent antimonials in Nepal

Drug-related factors and parasite resistance have been implicated in the failure of pentavalent antimonials (Sbv) in the Indian subcontinent; however, little information is available on host-related factors. Parasitologically confirmed kala-azar patients, treatment naïve to Sbv, were prospectively recruited at a referral hospital in Nepal and were treated under supervision with 30 doses of quality-assured sodium stibogluconate (SSG) 20 mg/kg/day and followed for 12 months to assess cure. Analysis of risk factors for treatment failure was assessed in those receiving ≥25 doses and completing 12 months of follow-up. One hundred and ninety-eight cases were treated with SSG and the overall cure rate was 77.3% (153/198). Of the 181 cases who received ≥25 doses, 12-month follow-up data were obtained in 169, comprising 153 patients (90.5%) with definite cure and 16 (9.5%) treatment failures. In the final logistic regression model, increased failure to SSG was significantly associated with fever for ≥12 weeks [odds ratio (OR) = 7.4], living in districts bordering the high SSG resistance zone in Bihar (OR = 6.1), interruption of treatment (OR = 4.3) and ambulatory treatment (OR = 10.2). Early diagnosis and supervised treatment is of paramount importance to prevent treatment failures within the control programm

Lutzomyia nuneztovari anglesi (Le Pont & Desjeux, 1984) as a vector of Leishmania amazonensis in a sub-Andean leishmaniasis focus of Bolivia

Recently, a new #Leishmania amazonensis focus was described in a sub-Andean region (1,450-2,100 meters above sea level) of Bolivia. In this area, three anthropophilic sandfly species were identified : #Lutzomyia nuneztovari anglesi Le Pont et Desjeux, 1984, which represented 86-99% of the captures, #Lu. galatiae Le Pont et al., 1998, and #Lu. shannoni Dyar 1929. Only #Lu. nuneztovari anglesi was found naturally infected by flagellates (16 of 1,715 females). Three #Leishmania stocks were isolated and analyzed by isoenzyme electrophoresis at 11 loci. No significant isoenzymatic differences were demonstrated between them and 7 stocks isolated from patients from the same area, and previously characterized as #L. amazonensis. Moreover, in a simplified protocol, the experimental infection of #Lu. nuneztovari anglesi by #L. amazonensis$was successful in 92$ is the vector of #L. amazonensis$ at Cajuata, Inquisivi, La Paz, Bolivia. (Résumé d'auteur

Lutzomyia nuneztovari anglesi (Le Pont & Desjeux, 1984) as a vector of Leishmania amazonensis in a sub-Andean leishmaniasis focus of Bolivia

Recently, a new #Leishmania amazonensis focus was described in a sub-Andean region (1,450-2,100 meters above sea level) of Bolivia. In this area, three anthropophilic sandfly species were identified : #Lutzomyia nuneztovari anglesi Le Pont et Desjeux, 1984, which represented 86-99% of the captures, #Lu. galatiae Le Pont et al., 1998, and #Lu. shannoni Dyar 1929. Only #Lu. nuneztovari anglesi was found naturally infected by flagellates (16 of 1,715 females). Three #Leishmania stocks were isolated and analyzed by isoenzyme electrophoresis at 11 loci. No significant isoenzymatic differences were demonstrated between them and 7 stocks isolated from patients from the same area, and previously characterized as #L. amazonensis. Moreover, in a simplified protocol, the experimental infection of #Lu. nuneztovari anglesi by #L. amazonensis$was successful in 92$ is the vector of #L. amazonensis$ at Cajuata, Inquisivi, La Paz, Bolivia. (Résumé d'auteur