Long-lasting insecticide-treated nets (LLINs) used to reduce the incidence of malaria in a municipal district of the Brazilian Amazon

Malaria is still the parasitic disease with the greatest worldwide impact. Recently in Brazil, almost all cases of the disease have been recorded in the Amazon region. The struggle against the vectors through insecticide treated nets associated with rapid diagnosis and treatment, is currently the main strategy. This study aimed to determine the protective effect of these devices on the incidence of malaria in one municipality in the Amazon, and was conducted with information from the Brazilian Ministry of Health and with the analysis of 10,050 slides of thick blood smears that were prepared and examined in loco. The Shapiro-Wilk test was used to determine the normality of the data and the Mann-Whitney test was used for all comparisons of the analyzed variables. The significance level was set at p≤0.01. The results revealed a significant reduction in the number of malaria cases in all analyzed variables, including the species of the parasite, the level and type of infection, and the gender and age of the diagnosed individual (p˂0.01). These findings confirmed that these devices are an important tool for disease control, presenting a new variable in combating the disease in the studied population. Therefore, the use of insecticide-treated nets is recommended as a preventive measure and guidance to the population regarding the correct way to use this device is required to avoid problems such as the loss of naturally acquired immunity, reduction in the protective effect of the device and the development of resistance to the insecticide.

An overview of malaria transmission from the perspective of Amazon Anopheles vectors

In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Ano- pheles species have been conducted, but with only short-lived success or no success at all. In this review, we review the literature on malaria transmission from the perspective of its Amazon vectors. Currently, it is possible to develop experimental Plasmodium vivax infection of the colonised and field-captured vectors in laboratories located close to Amazonian endemic areas. We are also reviewing studies related to the immune response to P. vivax infection of Anopheles aquasalis, a coastal mosquito species. Finally, we discuss the importance of the modulation of Plasmodium infection by the vector microbiota and also consider the anopheline genomes. The establishment of experimental mosquito infections with Plasmodium falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide interesting models for studying malaria in the Amazonian scenario is important. Understanding the molecular mechanisms involved in the development of the parasites in New World vectors is crucial in order to better determine the interaction process and vectorial competence.