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| Author(s): |
Márcio Junio Lima Siconelli
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2023-11-21 |
| Examining board members: |
Benedito Antonio Lopes da Fonseca;
Marcos Boulos;
Amaury Lelis Dal Fabbro;
Luiz Tadeu Moraes Figueiredo
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| Advisor: | Benedito Antonio Lopes da Fonseca |
| Abstract | |
West Nile fever virus (WNV) is an arbovirus of the Flavivirus genus (family: Flaviviridae) and was isolated first in Africa in 1937. Although it is widely distributed throughout Europe, the Middle East and in the USA, where seasonally causes epidemic outbreaks since 1999. WNV is considered emerging in South America and is responsible for causing a disease like dengue in humans, but it can cause involvement of the central nervous system (CNS) at around 1% of cases. In animals, equids in general, neurological impairment can reach 10%. This virus was officially registered for the first time in Brazil in 2014, a human case in the State of Piauí and the first animal detection was in horses from Espírito Santo in 2018, using molecular and viral isolation techniques. After that, states such as Paraná, São Paulo, Minas Gerais, Bahia, Ceará and Piauí also confirmed the detection of WNV in horses. Although birds play a central role in the transmission cycle, to date no isolation has been reported, and thus the enzootic cycle remains unknown. Given its recent detection in the southeast region and the lack of well-established surveillance, this study aimed to promote and propose a surveillance model for WNV in birds and horses in the State of São Paulo (ESP). Birds and horses that died with a neurological syndrome or an undetermined cause were studied. All equine samples studied were negative for animal rabies. CNS and heart (only for birds) samples were collected from these animals. The material collected was obtained thanks to the collaboration between animal rabies research and diagnosis institutes, universities, fauna enterprises and zoonosis surveillance units at ESP, called the ZooARBO SP Network. In this study, RT-qPCR was performed for WNV, Saint Louis encephalitis, and viruses of the Flavivirus and Alphavirus genera, in addition to histopathological diagnosis, with evaluation by Hematoxylin and Eosin and immunohistochemistry for WNV. Between 2017 and 2022, 1140 animals were evaluated, 364 equids and 776 wild animals, and of these, 679 birds, with Passeriformes being the most sampled order. All animals tested were negative for the tests performed. Despite this, 11 pigeons from the northeast region of ESP were tested using the PRNT80 serological technique, with neutralizing antibody titers against WNV being found in six animals, demonstrating for the first time the possible circulation of this virus in the state. Studies must be maintained so that the transmission cycle in Brazil is elucidated and surveillance is correctly directed. The establishment of the network was essential for carrying out this viral survey and showed that it is possible to expand the surveillance of arboviruses with the flowcharts and structures already existing in the ESP single health system, in addition to the importance of joining efforts with the agriculture and environment sectors. Only with this alignment will it be possible to establish a surveillance system based on sentinels, effective so that the necessary prevention and control actions are carried out on time in the presence of a confirmed case, thus avoiding an epidemic. (AU) | |
| FAPESP's process: | 20/01632-4 - Evaluation of the circulation of West Nile Virus in the State of São Paulo: birds and equines as a sentinel population |
| Grantee: | Márcio Junio Lima Siconelli |
| Support Opportunities: | Scholarships in Brazil - Doctorate |