A new continuous cell line from the mosquito Psorophora confinnis (Diptera: Culicidae) and its susceptibility to infections with some arboviruses.

A new cell line, PC-0199-BR, was established from embryonated eggs of the mosquito Psorophora confinnis. To date (September 2000) it has had 62 continuous passages. This is the first report of a cell line of mosquitoes belonging to the genus Psorophora. Cell growth initially was achieved in the MM/VP12 medium, supplemented with 20% fetal bovine serum; however, the subcultures were later adapted to Grace's medium with 10% fetal bovine serum. Cell morphology in the primary cultures was heterogeneous; but later in the established cell line, the predominant cell type was epithelioid. Cultured cells were predominantly diploid (2n=6); however, chromosome abnormalities were observed in a small proportion of the cells in later passages. C and G band patterns were also determined in the karyotype. The cell line isozyme profiles coincided with pupae and adult samples of the species taken from the same colony. A preliminary arbovirus susceptibility study for the cell line was undertaken. No evidence was observed of contamination of the cell line with bacteria, fungi or mycoplasma.

Epidemic Venezuelan equine encephalitis in La Guajira, Colombia, 1995.

In 1995, the first Venezuelan equine encephalitis (VEE) outbreak in Colombia in 22 years caused an estimated 75,000 human cases, 3000 with neurologic complications and 300 fatal, in La Guajira State. Of the state's estimated 50,000 equines, 8% may have died. An epizootic IC virus, probably introduced from Venezuela, was rapidly amplified among unvaccinated equines. Record high rainfall, producing high densities of vector Aedes taeniorhynchus, led to extensive epidemic transmission (30% attack rate) in the four affected municipalities. Native Wayuu Indians, constituting 24% of the state's population, were at increased risk of infection (risk ratio, 3.3; 95% confidence interval, 2.2-5.3). Epidemiologic studies found no evidence of human-to-human transmission. A higher-than-expected number of abortions during the outbreak confirmed a previously suspected abortifacient role of VEE infection. Pesticide applications and a mass equine vaccination program contributed to preventing the outbreak's spread south of La Guajira.

Establecimiento y mantenimiento de una colonia de Aedes taeniorhynchus, Wiedemann, 1821 (Díptera: Culicidae) cepa Barranquilla, Colombia / Establishment and maintainance of a colony of Aedes taeniorhynchus, Wiedemann, 1821 (Diptera: Culicidae) strain Barranquilla, Colombia

Se estableció una colonia del mosquito Aedes taeniorhynchus, eficiente vector del virus de la encefalitis equina venezolana, tipo epidemo-epizoótico, a partir de formas adultas, recolectados en regiones cercanas a Barranquilla, Atlántico (Colombia). Se estudiaron algunos aspectos de la biología de este insecto (ciclo de vida y logevidad), elaboración de tablas de vida e igualmente se maximizaron algunos parámetros físicos, ambientales y nutricionales que garantizan el mantenimiento y la continuidad de la especie en condiciones de laboratorio. Esta colonia fue establecida con el objeto de proporcionar la materia prima biológica para los explantes de tejidos embrionarios que se han venido utilizando para establecer líneas celulares de crecimiento continuo