Estudos epidemiológicos sobre arbovírus em populações rurais e urbanas do estado do Amazonas

Abstract

Arbovirosis are currently recognized by the World Health Organization as a global problem. Most arbovirosis are summarized in diseases with acute and nonspecific symptoms such as fever, headache and muscle pain. Although self limited, these symptoms create relevant social and economic impacts. In Brazil, the arbovirosis caused by viruses belonging to the genus Alphavirus, Flavivirus and Orthobunyavirus and are the main cause of outbreaks or epidemics. This study aimed to study the circulation of arbovirus mayaro, venezuelan equine encephalitis virus, yellow fever virus, Saint Louis encephalitis virus and oropouche virus in a rural and an urban area of the State of Amazonas, Brazil. Therefore, the serology for detection of immunoglobulin G was used to assess the prevalence of antibodies against these viruses in 335 residents of a rural community in the state of Amazonas and PCR was used to assess the incidence of these viruses in 250 samples collected in urban area of Manaus. The results for serology suggest the movement of mayaro virus in the rural community. The seroprevalence detected in the samples was 41.5%. There was no significant relationship to risk for mayaro infection between genders (p value = 0.7760) or between age groups (p value = 0.9422). The positive serology detected among 39 children younger than 10 years indicates a recent infection. The factors of protection against mayaro infection detected were the use of mosquito net (p value = 0.0119) and the presence of animals in surrounding (p value = 0.0407). The risk factors identified for mayaro infection were the location of residence in towns near the forest (p value <0.0001) and presence of toilet in or near the home (p value = 0.0415). The serological results suggest that infection with mayaro occurred less than 10 years in the vicinity of residences analyzed. Molecular analysis of the samples collected in the urban area of Manaus not detected genomic fragments of arboviruses. Factors such as low viremia at the time of blood collection and storage of serum samples may have contributed to the non-detection of genomic fragments. However, the protocol for the detection of genomic fragments of arboviruses based on the PCR technique is already used in research centers and surveillance of Fundação de Medicina Tropical do Amazonas FMTAM and Instituto Leônidas e Maria Deane ILMD/FIOCRUZ.