[Epidemiology of encephalitis caused by arbovirus in the Brazilian Amazonia].
Abstract: An overview of ecological, epidemiological and clinical findings of potential arthropod-borne encephalitis viruses circulating in the Amazon Region of Brazil are discussed. These viruses are the Eastern Equine Encephalitis (EEE), Western Equine Encephalitis (WEE), St. Louis Encephalitis (SLE), Mucambo (MUC) and Pixuna (PIX). These last two are subtypes (III and IV) of Venezuelan Equine Encephalitis virus. The areas of study were the highways and projects of development, as well as places where outbreaks of human diseases caused by arboviruses had been detected. These viruses are widespread in all Amazonia, and at least four of them, EEE, WEE, SLE and MUC are pathogenic to man. EEE and WEE infections were detected by serology, while SLE and MUC by either serology and virus isolation. The PIX virus has the lowest prevalence and, it was isolated in only a few cases, one being from a laboratory infection. Wild birds are the main hosts for all these viruses, except MUC, whose major hosts are rodents. The symptoms presented by infected people were generally a mild febrile illness. Although, jaundice was observed in two individuals from whom SLE was isolated. A comparison of the clinical symptoms presented by the patients in the Amazon Region and other areas of America, especially in the USA is made. In Brazilian Amazon region epidemics have not been detected although, at least, one EEE epizootic was recorded in Bragança, Para State, in 1960. At that time, of 500 horses that were examined 61% were positive to EEE by HI and of them 8.2% died. On the other hand, SLE has caused four epizootics in a forest near Belem. Wild birds and sentinel monkeys were infected, but no human cases were reported.
Publication Date: 1991-11-01 PubMed ID: 1844977
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- English Abstract
- Journal Article
Summary
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The research paper discusses the occurrence, effects, and spread of encephalitis caused by arthropod-borne viruses in the Amazon region of Brazil, focusing specifically on five viruses: Eastern Equine Encephalitis (EEE), Western Equine Encephalitis (WEE), St. Louis Encephalitis (SLE), Mucambo (MUC) and Pixuna (PIX).
Epidemiology and Geographical Spread
- The study reveals that these viruses are present across the entire Amazon region, predominantly in areas with development projects, highways, and locations where previous outbreaks of arbovirus-caused human diseases have been identified.
- EEE, WEE, SLE and MUC were identified as harmful to humans, with EEE and WEE detected through serology, while SLE and MUC were confirmed via both serology and virus isolation.
- PIX virus had the lowest prevalence and was only isolated in a few cases, including a laboratory infection incident.
Hosts and Symptoms of the Viruses
- Wild birds were found to be the primary hosts for all the viruses, barring MUC, which primarily affects rodents.
- The symptoms presented by those infected generally included a mild febrile illness, however, two individuals infected with SLE exhibited jaundice.
- The researchers also highlighted that Brazilian Amazon region has yet to experience an epidemic, despite the detection of an EEE epizootic (an outbreak in animals) in the region in 1960. During this outbreak, of the 500 horses examined, 61% tested positive for EEE and 8.2% of these horses died.
- Meanwhile, SLE was responsible for four outbreaks in a forest near Belem where wild birds and sentinel monkeys were infected, although no human cases were reported.
Comparison with other Regions
- The research draws a comparison between the clinical symptoms presented by patients in the Amazon region, with those in other areas of America, particularly the USA. However, the specifics of these comparisons were not outlined in the abstract.
In conclusion, the paper provides an in-depth analysis of the arbovirus-caused encephalitis landscape in the Amazon region of Brazil, highlighting the need for continual monitoring and control measures to prevent potential epidemics.
Cite This Article
APA
Vasconcelos PF, Da Rosa JF, Da Rosa AP, Dégallier N, Pinheiro Fde P, Sá Filho GC.
(1991).
[Epidemiology of encephalitis caused by arbovirus in the Brazilian Amazonia].
Rev Inst Med Trop Sao Paulo, 33(6), 465-476.
Publication
Researcher Affiliations
- Instituto Evandro Chagas, Centro Colaborador da OMS em Arboviroses, Fundação SESP, Belém, Pará, Brasil.
MeSH Terms
- Animals
- Birds / microbiology
- Brazil / epidemiology
- Encephalitis Viruses
- Encephalitis, Arbovirus / epidemiology
- Encephalitis, Arbovirus / microbiology
- Encephalomyelitis, Equine / epidemiology
- Encephalomyelitis, Equine / microbiology
- Humans
- Insect Vectors / microbiology
- Mice
Citations
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