Gonotrophic cycle estimate for Culex quinquefasciatus in Mérida, Yucatán, México

West Nile virus (WNV) has been present in the Yucatán State, México, since 2002. Culex quinquefasciatus, one of the main vectors of WNV transmission in the United States, is also common in Mexico and may be a key vector of WNV transmission to humans in the Yucatán. The aim of this study was to determine the length of the gonotrophic cycle and the survival rates of Cx. quinquefasciatus from Mérida, Yucatán, during the rainy versus the dry season. Mosquitoes were collected during 25-day periods in October (rainy season) and in April (dry season), and captured females were classified by abdominal appearance (freshly fed, late-stage fed, half gravid, and subgravid). To determine the age structure as nulliparous and parous females and to calculate the gonotrophic cycle through a time series and the mosquito survival, we used Davidson formulae. Also, vitellogenesis analysis to monitor egg maturity was conducted during both seasons. Cross-correlation data suggested a similar length of the gonotrophic cycle (4 days) in both seasons. Oogenic development required a minimum of 72 h in each season. However, survival of the mosquito population collected in the rainy season was significantly higher (0.91) with a mean temperature of 28 ± 1.57°C than was survival in the dry season (0.78) with a mean temperature of 29 ± 1.10°C. Survival, although higher during the rainy season, did not influence the length of the gonotrophic cycle of Cx. quinquefasciatus in Yucatán

Epidemia de dengue 4 en Yucatán, México, 1984

An outbreak of dengue 4 occurred in the Yucatán, México in 1984. During the course of the outbreak, 538 of 5486 reported cases of dengue-like illness were studied; 200 were confirmed as dengue serologically and/or virologically. Dengue 4 virus was isolated from 34 patients and dengue 1 from one. Severe haemorrhagic symptoms were observed in 9 laboratory confirmed patients, including four deaths. Thus, the outbreak in Yucatán is the second dengue epidemic in the Americas after the Cuban epidemic in 1981 in which a number of patients suffered from haemorrhagic complications. It was notable that 5 of 9 hospitalized, severe cases were young adults and that only one met the WHO criteria of DHF, in contrast to primary pediatric nature of DHF in Southeast Asia. In this paper we describe clinical, serologic, and virologic studies conducted during the outbreak.Un brote de dengue 4 ocurrió en Yucatán, México en 1984. Durante el curso del brote, 538 de 5486 casos reportados como dengue clínico fueron estudiados; 200 fueron confirmados como dengue, por estudios serológicos y/o virológicos. El dengue tipo 4 fue aislado de 34 pacientes y dengue 1 de un paciente. Síntomas hemorrágicos severos fueron observados en 9 pacientes confirmados por pruebas de laboratorio, de los cuales 4 fallecieron. Así, el brote en Yucatán es la segunda epidemia de dengue en las Américas después de la epidemia en Cuba en 1981 por el número de pacientes que sufrieron de complicaciones hemorrágicas. Fué notable que 5 de 9 casos hospitalizados, fueron adultos jóvenes y que únicamete un paciente reunió los criterios de la Organización Mundial de la Salud para la Fiebre Hemorrágica por Dengue (FHD), en contraste con los casos pediátricos de FHD del Sureste de Asia. En este artículo describimos los estudios clínicos, serológicos y virológicos realizados durante el brote

Gonotrophic cycle estimate for Culex quinquefasciatus in Mérida, Yucatán, México

West Nile virus (WNV) has been present in the Yucatán State, México, since 2002. Culex quinquefasciatus, one of the main vectors of WNV transmission in the United States, is also common in Mexico and may be a key vector of WNV transmission to humans in the Yucatán. The aim of this study was to determine the length of the gonotrophic cycle and the survival rates of Cx. quinquefasciatus from Mérida, Yucatán, during the rainy versus the dry season. Mosquitoes were collected during 25-day periods in October (rainy season) and in April (dry season), and captured females were classified by abdominal appearance (freshly fed, late-stage fed, half gravid, and subgravid). To determine the age structure as nulliparous and parous females and to calculate the gonotrophic cycle through a time series and the mosquito survival, we used Davidson formulae. Also, vitellogenesis analysis to monitor egg maturity was conducted during both seasons. Cross-correlation data suggested a similar length of the gonotrophic cycle (4 days) in both seasons. Oogenic development required a minimum of 72 h in each season. However, survival of the mosquito population collected in the rainy season was significantly higher (0.91) with a mean temperature of 28 ± 1.57°C than was survival in the dry season (0.78) with a mean temperature of 29 ± 1.10°C. Survival, although higher during the rainy season, did not influence the length of the gonotrophic cycle of Cx. quinquefasciatus in Yucatán

Serologic Evidence of West Nile Virus Infection in Horses, Yucatan State, Mexico

Serum samples were obtained from 252 horses in the State of Yucatan, Mexico, from July to October 2002. Antibodies to West Nile virus were detected by epitope-blocking enzyme-linked immunosorbent assays in three (1.2%) horses and confirmed by plaque reduction neutralization test. We report the first West Nile virus activity in the State of Yucatan

Ilustración del proceso constructivo de vías primarias, secundarias y terciarias basado en las especificaciones técnicas de construcción de carreteras del Instituto Nacional de vías (INVIAS)

: figuras, tablas ; 28 cmEsta cartilla metodológica describe a través de ilustraciones el proceso constructivo de vías primarias, secundarias y terciarias, basado en las especificaciones técnicas de construcción de carreteras del Instituto Nacional de Vías (INVIAS)PregradoIngeniero CivilIngeniería Civi