The rapid and disorderly urbanization in the Amazon has resulted in the insertion of forest fragments into cities, causing the circulation of arboviruses, which can involve hematophagous arthropods and free-ranging birds in the transmission cycles in urban environments. This study aimed to evaluate the circulation of arboviruses in free-ranging birds and hematophagous arthropods captured in an Environmental Protection Area in the Belem metropolitan area, Brazil. Birds were captured using mist nets, and hematophagous arthropods were collected using a human protected attraction technique and light traps. The birds’ sera were subjected to a hemagglutination inhibition test to detect antibodies against 29 arbovirus antigens. Arthropod macerates were inoculated into C6/36 and VERO cell cultures to attempt viral isolation and were tested using indirect immunofluorescence, subsequent genetic sequencing and submitted for phylogenetic analysis. Four bird sera were positive for arbovirus, and one batch of Psorophora ferox was positive for Flavivirus on viral isolation and indirect immunofluorescence. In addition, the Ilheus virus was detected in the sequencing and phylogenetic analysis. The presence of antibodies in sera from free-ranging birds and the isolation of Ilheus virus in Psorophora ferox indicate the circulation of arboviruses in forest remnants in the urban center of Belem.

Viruses with encephalitogenic potential can cause neurological conditions of clinical and epidemiological importance, such as Saint Louis encephalitis virus, Venezuelan equine encephalitis virus, Eastern equine encephalitis virus, Western equine encephalitis virus, dengue virus, Zika virus, Chikungunya virus, Mayaro virus and West Nile virus. The objective of the present study was to determine the number of arboviruses with neuroinvasive potential isolated in Brazil that corresponds to the collection of viral samples belonging to the Section of Arbovirology and Hemorrhagic Fevers (SAARB/IEC) of the Laboratory Network of National Reference for Arbovirus Diagnosis from 1954 to 2022. A total of 1,090 arbovirus samples with encephalitogenic potential were isolated from mice. From a total of 7,054 samples intended for cell culture. The isolates from mosquitoes totaled 659 viruses. The emergence of new arboviruses may be responsible for diseases still unknown to humans, making the Amazon region a hotspot for infectious diseases due to its fauna and flora species characteristics. The detection of circulating arboviruses with the potential to cause neuroinvasive diseases is constant, which justifies the continuation of active epidemiological surveillance work that offers adequate support to the public health system regarding the virological diagnosis of circulating arboviruses in Brazil.

Introdução:  Os arbovírus neurotrópicos representam um importante problema de saúde em escala global, sendo necessário a utilização de medidas de prevenção, controle e diagnóstico. Objetivo:  Avaliar a efetividade da infecção de dois arbovírus neurotrópicos, vírus do Nilo Ocidental (WNV) e vírus da Encefalite de Saint Louis (SLEV), em células de neuroblastoma humano (IMR-32). Metodologia: As suspensões-estoques dos vírus foram tituladas por ensaio de placa com incubação de 120 h para WNV e 168 h para SLEV. Os isolados foram inoculados em garrafas para cultura de células que apresentavam 80% de confluência da monocamada celular e observadas por microscopia de contraste de fase por 72 h pós infecção a fim de verificar alterações morfológicas sugestivas de efeito citopático (ECP). Em seguida, as culturas foram submetidas ao ensaio de Imunofluorescência Indireta (IFI) para detecção de antígenos virais. Resultados: O título infeccioso do SLEV apresentou-se mais baixo em relação ao WNV. Em 72 h, foram observadas alterações morfológicas nas culturas inoculadas, caracterizando um ECP resultante da infecção viral, com ECP mais acentuado na cultura inoculada com WNV, confirmado pela presença de antígenos virais nas células infectadas detectados pelo teste de IFI. Conclusão: a linhagem celular IMR-32 apresentou suscetibilidade à infecção por WNV e SLEV, representando um modelo alternativo eficaz para o isolamento de arbovírus neurotrópicos.