Saint Louis encephalitis virus (SLEV) is a member of the Japanese-encephalitis virus serocomplex of the genus Flavivirus. SLEV is broadly distributed in the Americas and the Caribbean Islands, where it is usually transmitted by mosquitoes of the genus Culex and primarily to birds and mammalian-hosts. Humans are occasionally infected by the virus and are dead-end hosts. SLEV causes encephalitis in temperate regions, while in tropical regions of the Americas, several human cases and a wide biological diversity of SLEV-strains have been reported. The phylogenetic analysis of the envelope (E) protein genes indicated eight-genotypes of SLEV with geographic overlap. The present paper describes the genotyping of two SLEV viruses detected in mosquito-pools collected in northern Colombia (department of Cordoba). We used reverse transcription-polymerase chain reaction to amplify a fragment of theE-gene to confirm the virus identity and completeE-gene sequencing for phylogenetic analysis and genotyping of the two-SLEV viruses found circulating in Córdoba. This is the first report of SLEV genotype IV in Colombia (Córdoba) in mosquitoes from a region of human inhabitation, implicating the risk of human disease due to SLEV infection. Physicians should consider SLEV as a possible aetiology for undiagnosed febrile and neurologic syndromes among their patients who report exposure to mosquito-bites.
Se realizó un análisis multitemporal del paisaje del municipio de Puerto Berrío (Antioquia), para los años 1985, 2001 y 2011, utilizando sensores remotos en un área de 15.000 ha. Se evidenció gran dinámica en la estructura y composición del paisaje y una alta heterogeneidad en el 2001, con tendencia a homogenización en el 2011. Se detectaron cambios “positivos” de pastos a rastrojos y bosques de 1985 al 2001, mientras que del 2001 al 2011 se evidenciaron pérdidas y fragmentación de bosques. Esta transformación se relaciona con el abandono de las tierras y el desplazamiento en las décadas de 1980 y 1990, así como con el posterior retorno y la reactivación de las actividades económicas en la década del 2000. Se estimaron unas rutas de conectividad potencial norte-sur entre los bosques de interés, mostrando alta fragmentación transversal en el paisaje.
BackgroundWest Nile virus (WNV) is a member of the genus Flavivirus, and it is transmitted between Culex sp. mosquitoes and avian hosts. Equids and humans are commonly infected with WNV as dead-end hosts, and the signs and symptoms of infection range from mild illness to neurologic symptoms as encephalitis, meningitis and sometimes death. Previous phylogenetic studies have classified WNV into six genetically distinct lineages and provided valuable insight on WNV dispersal patterns within the Americas and its emergence in different geographic areas. In this study, we isolated, sequenced and genetically characterized the NS5 and envelope genes for two WNV strains detected from Northern of Colombia. Herein we describe the evolutionary relationships with representative WNV-strains isolated in a variety of epidemic outbreaks and countries, to define the phylogeographic origin and possible implications in the epidemiology of this emergent virus in Colombia.FindingsFragments of the NS5 and Envelope genes were amplified with RT-PCR and sequenced to obtain 1186-nt and 1504-nt portions, respectively. Our sequences were aligned with 46 sequences from WNV-strains collected in the U.S., Mexico and Argentina for phylogenetic reconstruction using Bayesian methods. Sequence analyses identified unique non-synonymous substitutions in the envelope gene of the WNV strains we detected, and our sequences clustered together with those from the attenuated Texas – 2002 genotype.ConclusionsA new strain closely related to attenuated strains collected in Texas during 2002 was identified from Colombia by phylogenetic analysis. This finding may explain the absence of human/equine cases of WNV-encephalitis or severe disease in Colombia and possibly other regions of South America. Follow-up studies are needed in ecosystems used by migratory birds areas and virological/entomological surveillance.
Los mosquitos tienen un papel importante en la transmisión de parásitos y patógenos con efectos en la salud humana y animal, y algunos son también indicadores de la salud de los ecosistemas. Aunque se ha estudiado bastante la presencia y la distribución de estos insectos para entender la dinámica de las enfermedades que transmiten y diseñar estrategias para su monitoreo y el estudio de sus especies, se conoce relativamente poco sobre su ecología en muchas regiones tropicales. El género Trichoprosopon Theobald, de la tribu Sabethini, incluye unas 13 especies de mosquitos con distribución en el Neotrópico en hábitats principalmente rurales y selváticos. Algunas especies se han encontrado infectadas con arbovirus como el Bussuquara, el de la encefalitis de San Luis, el Ilhéus, el Pixuna y el Wyeomyia, en tanto que otras se consideran indicadores biológicos por su asociación con ecosistemas particulares en microambientes naturales de parques urbanos o áreas conservadas con presencia de plantas epífitas como las bromelias. En la presente revisión se actualiza la información sobre el género Trichoprosopon en Colombia, especialmente en lo relativo a su importancia médica y los registros históricos de las especies con presencia en el país, adicionando algunos nuevos a partir de muestreos en las costas Caribe y del Pacífico, en las montañas altoandinas y los valles interandinos (periodo 2009-2018). Se presenta la lista de especies con su distribución y notas ecológicas, registrándose siete especies válidas en diez departamentos que ocupan hábitats con criaderos en plantas fitotelmata: [Tr. andinum Leví-Castillo, Tr.compressum Lutz, Tr. digitatum (Rondani), Tr. evansae Antunes, Tr. lampropus Howard, Dyar & Knab,Tr. lanei (Antunes) y Tr. pallidiventer (Lutz)]; así mismo, se registran dos nuevas especies que harían parte de los complejos descritos en ecosistemas cafeteros andinos.
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