RESUMO
BACKGROUND: Free-ranging non-human primates (NHPs) can host a variety of pathogenic microorganisms, such as arboviruses, which include the yellow fever virus (YFV). This study aimed to detect the circulation of YF and other arboviruses in three wild Alouatta caraya populations in forests in southern Brazil. METHODS: We collected 40 blood and serum samples from 26 monkeys captured/recaptured up to four times from 2014 to 2016, searching for evidence of arboviruses by virus isolation, PCR, and neutralization tests. RESULTS: Viral isolation and genome detection were negative; however, we detected neutralizing antibodies against the Saint Louis, Ilhéus, and Icoaraci viruses in three NHPs. CONCLUSIONS: Saint Louis Encephalitis, Ilhéus, and Icoaraci viruses circulated recently in the region. Future studies should investigate the role of NHPs, other vertebrate hosts and wild vectors in the region's arbovirus circulation and the potential risks of the arboviruses to wildlife, domestic animals, and humans.
Assuntos
Alouatta caraya , Encefalite de St. Louis/veterinária , Infecções por Flavivirus/veterinária , Doenças dos Macacos/epidemiologia , Febre do Vale de Rift/epidemiologia , Animais , Anticorpos Antivirais/sangue , Brasil/epidemiologia , Vírus da Encefalite de St. Louis/isolamento & purificação , Encefalite de St. Louis/epidemiologia , Encefalite de St. Louis/virologia , Flavivirus/isolamento & purificação , Infecções por Flavivirus/epidemiologia , Infecções por Flavivirus/virologia , Febre do Vale de Rift/virologia , Vírus da Febre do Vale do Rift/isolamento & purificaçãoRESUMO
History is replete with emergent pandemic infections that have decimated the human population. Given the shear mass of humans that now crowd the earth, there is every reason to suspect history will repeat itself. We describe three RNA viruses that have recently emerged in the human population to mediate severe neurological disease. These new diseases are results of new mutations in the infectious agents or new exposure pathways to the agents or both. To appreciate their pathogenesis, we summarize the essential virology and immune response to each agent. Infection is described in the context of known host defenses. Once the viruses evade immune defenses and enter central nervous system (CNS) cells, they rapidly co-opt host RNA processing to a cataclysmic extent. It is not clear why the brain is particularly susceptible to RNA viruses; but perhaps because of its tremendous dependence on RNA processing for physiological functioning, classical mechanisms of host defense (eg, interferon disruption of viral replication) are diminished or not available. Effectiveness of immunity, immunization and pharmacological therapies is reviewed to contextualize the scope of the public health challenge. Unfortunately, vaccines that confer protection from systemic disease do not necessarily confer protection for the brain after exposure through unconventional routes.
Assuntos
Viroses do Sistema Nervoso Central/epidemiologia , Viroses do Sistema Nervoso Central/virologia , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/virologia , Animais , Aves , Viroses do Sistema Nervoso Central/patologia , Doenças Transmissíveis Emergentes/patologia , Humanos , Vírus da Influenza A/patogenicidade , Influenza Humana/epidemiologia , Influenza Humana/patologia , Influenza Humana/virologia , Infecções por Orthomyxoviridae/epidemiologia , Infecções por Orthomyxoviridae/patologia , Infecções por Orthomyxoviridae/virologia , Parechovirus/patogenicidade , Febre do Vale de Rift/epidemiologia , Febre do Vale de Rift/patologia , Febre do Vale de Rift/virologiaRESUMO
All known Rift Valley fever(RVF) outbreaks in Kenya from 1950 to 1998 followed periods of abnormally high rainfall. On an interannual scale, periods of above normal rainfall in East Africa are associated with the warm phase of the El Niño/Southern Oscillation (ENSO) phenomenon. Anomalous rainfall floods mosquito-breeding habitats called dambos, which contain transovarially infected mosquito eggs. The eggs hatch Aedes mosquitoes that transmit the RVF virus preferentially to livestock and to humans as well. Analysis of historical data on RVF outbreaks and indicators of ENSO (including Pacific and Indian Ocean sea surface temperatures and the Southern Oscillation Index) indicates that more than three quarters of the RVF outbreaks have occurred during warm ENSO event periods. Mapping of ecological conditions using satellite normalized difference vegetation index (NDVI) data show that areas where outbreaks have occurred during the satellite recording period (1981-1998) show anomalous positive departures in vegetation greenness, an indicator of above-normal precipitation. This is particularly observed in arid areas of East Africa, which are predominantly impacted by this disease. These results indicate a close association between interannual climate variability and RVF outbreaks in Kenya.
Assuntos
Clima , Surtos de Doenças , Febre do Vale de Rift/epidemiologia , Aedes , Animais , Bovinos , Reservatórios de Doenças , Humanos , Insetos Vetores , Quênia/epidemiologia , Chuva , Febre do Vale de Rift/transmissão , Ovinos , TemperaturaRESUMO
Entre 1950 e 1998 houve surtos de febre no Vale do Rift, no Quênia, após períodos de aumentos pluviométricos anormais. Em escala interanual, esses períodos estiveram associados à fase quente do fenômeno ENSO (El Niño/Southern Oscillation) na Africa Oriental. As chuvas alagam os criadouros de mosquitos - dambos -, cujos ovos, infectados pela via transovariana, eclodem, produzindo mosquitos Aedes, transmissores do vírus da febre do Vale do Rift aos seres humanos e, em especial, ao gado. A análise dos dados históricos sobre surtos de febre do Vale do Rift e indicadores do fenômeno ENSO - incluindo temperaturas superficiais dos Oceanos Pacífico e Indico e o Indice de Oscilaçäo Sul - mostrou que mais de 75 por cento dos surtos ocorreram em períodos quentes do ENSO. Na época estudada - 1981-1998 -, o mapeamento das condiçöes ecológicas via satélite (NDVI) - com dados normalizados sobre diferenças na vegetaçäo - evidenciou que as áreas de surto apresentaram desvios anômalos na intensidade do verde da vegetaçäo (indicador de pluviosidade alta), em particular, nas regiöes áridas da Africa Oriental - as mais afetadas pela febre. Os resultados indicam associaçäo estreita entre variabilidade climática interanual e surtos de febre do Vale do Rift no Quênia.
Assuntos
Surtos de Doenças , Febre do Vale de Rift/epidemiologia , AedesRESUMO
Rift Valley fever (RVF) is a mosquito-borne viral disease which manifested itself during recent epidemics and revealed its significant potential of emergence. Studies on molecular epidemiology undertaken to better understand the factors leading to RVF emergence, have confirmed the mode of circulation of the virus and highlighted probable risks and obstacles for prevention and control. As for several other viral agents, molecular epidemiology is becoming a useful tool in the study of the emergence of RVF as a serious infectious disease.