Dog skin parasite load, TLR-2, IL-10 and TNF-α expression and infectiousness.

Visceral leishmaniosis is a zoonotic disease that is transmitted by Lutzomyia longipalpis sandflies. Dogs are the main peri-urban reservoir of the disease, and progression of canine leishmaniosis is dependent on the type of immune response elaborated against the parasite. Type 1 immunity is characterized by effective cellular response, with production of pro-inflammatory cytokines such as tumour necrosis factor alpha (TNF-α). In contrast, Type 2 immunity is predominantly humoral, associated with progression of the disease and mediated by anti-inflammatory cytokines such as interleukin 10 (IL-10). Although seemly important in the dynamics of leishmaniosis, other gene products such as toll-like receptor 2 (TRL-2) and inducible nitric oxide synthase (iNOS) exert unclear roles in the determination of the type of immune response. Given that the dog skin serves as a micro-environment for the multiplication of Leishmania spp., we investigated the parasite load and the expression of TLR-2, iNOS, IL-10 and TNF-α in the skin of 29 infected and 8 control dogs. We found that increased parasite load leads to upregulation of TLR-2, IL-10 and TNF-α, indicating that abundance of these transcripts is associated with infection. We also performed a xenodiagnosis to demonstrate that increased parasitism is a risk factor for infectiousness to sandflies.

Entoepidemiology of Chagas disease in the Western region of the State of São Paulo from 2004 to 2008, and cytogenetic analysis in Rhodnius neglectus (Hemiptera, Triatominae).

To complement the epidemiological data and assist in the prophylaxis of Chagas disease in the State of São Paulo, we examined entomological lifting conducted in 40 municipalities of the Western region of the state from 2004 to 2008, highlighted the main vector species in this region, and reanalyzed the cytogenetic characteristics of Rhodnius neglectus from 3 different Brazilian states (Formoso/GO, Frutal/MG, Guaíra/SP, and Pitangueiras/SP). The municipalities of Castilho and Santo Antônio do Acaranguá registered the highest relative amounts of notifications. The main species notified in Western São Paulo were Triatoma sordida and R. neglectus. We collected a large number of T. sordida in 2005 and noted the absence of notification of infected insects in 2008. We observed no variation in chromosomal characteristics of R. neglectus of different states. These data are complementary to the survey presented from 1990 to 1999, as the vector species were the same (T. sordida and R. neglectus), with emphasis on T. sordida. We corroborate the future colonization domiciliary initially proposed for T. sordida in the region and underscore the importance of vector control programs in the prophylaxis of Chagas disease. Furthermore, we observed that the populations of R. neglectus in Brazil showed no intraspecific variation and we corroborated the chromosomal patterns originally described. These data are important for understanding the evolution of these hematophagous insects, which are vectors of Chagas disease.