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Mayaro virus produces nonspecific, sublethal disease symptoms, often confused with dengue, but with symptoms of arthalgias that can cause incapacitating disability. Outbreaks have been localized and sporadic in the Pan-Amazonia forest since its first isolation in 1954 (Trinidad and Tobago). The literature available is scarce, diverse and dispersed. Mayaro virus is an alphavirus, phylogenetically related to the Semliki forest antigenic complex. UNA and Mayaro viruses are the only viruses of this complex that have been isolated in the New World. Mayaro consists of single-stranded RNA of positive charge, length of 12 kb, subdivided into genomic and subgenomic regions, which encode nonstructural and structural proteins respectively. Mayaro shows a great plasticity in vertebrate host infection, whereas high specificity in the family Culicidae (mosquitoes). Risk factors of infection are associated with forest areas of northern South America and the rainy season. Two genotypes of MAYV have been identified, L (Belterra, Brazil) and D (widely distributed in the Pan-Amazonia). The enzootic cycle is similar to the jungle cycle of yellow fever, which involves Haemagogus mosquitoes and monkeys as reservoirs. However, the involvement of other secondary vectors and other hosts may be important in spread of the virus. Humans may have high levels of viremia, and efficient experimental transmission has been demonstrated in Aedes aegypti, Aedes albopictus and Aedes scapularis, suggesting a significant risk to public health in urban, rural and peridomestic locations close to enzootic foci of Mayaro virus.

Since the early 1980s, visceral leishmaniasis (VL) which is, in general, a rural zoonotic disease, has spread to the urban centers of the north, and now the south and west of Brazil. The principal drivers differ between cities, though human migration, large urban canid populations (animal reservoir), and a decidedly peripatetic and adaptable sand fly vector are the primary forces. The exact number of urban cases remains unclear as a result of challenges with surveillance. However, the number of urban cases registered continues to increase annually. Most control initiatives (e.g. culling infected dogs and household spraying to kill the sand fly) could be effective, but have proven hard to maintain at large scales due to logistical, financial and other reasons. In this article, the urbanization of VL in Brazil is reviewed, touching on these and other topics related to controlling VL within and outside Brazil., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

We performed a longitudinal study of adult survival of Anopheles darlingi, the most important vector in the Amazon, in a malarigenous frontier zone of Brazil. Survival rates were determined from both parous rates and multiparous dissections. Anopheles darlingi human biting rates, daily survival rates and expectation of life where higher in the dry season, as compared to the rainy season, and were correlated with malaria incidence. The biting density of mosquitoes that had survived long enough for completing at least one sporogonic cycle was related with the number of malaria cases by linear regression. Survival rates were the limiting factor explaining longitudinal variations in Plasmodium vivax malaria incidence and the association between adult mosquito survival and malaria was statistically significant by logistic regression (P<0.05). Survival rates were better correlated with malaria incidence than adult mosquito biting density. Mathematical modeling showed that P. falciparum and P. malariae were more vulnerable to changes in mosquito survival rates because of longer sporogonic cycle duration, as compared to P. vivax, which could account for the low prevalence of the former parasites observed in the study area. Population modeling also showed that the observed decreases in human biting rates in the wet season could be entirely explained by decreases in survival rates, suggesting that decreased breeding did not occur in the wet season, at the sites where adult mosquitoes were collected. For the first time in the literature, multivariate methods detected a statistically significant inverse relation (P<0.05) between the number of rainy days per month and daily survival rates, suggesting that rainfall may cause adult mortality.