Centro de Investigaciones Entomológicas

Forecasting models were developed for predicting Aedes aegypti larval indices in an endemic area for dengue (cities of Tartagal and Orá n, northwestern Argentina), based on the Breteau and House indices and environmental variables considered with and without time lags. Descriptive models were first developed for each city and each index by multiple linear regressions, followed by a regional model including both cities together. Finally, two forecasting regional models (FRM) were developed and evaluated. FRM 2 for the Breteau index and House index fit the data significantly better than FRM 1 . An evaluation of these models showed a higher correlation FRM 1 than for FRM 2 for the Breteau index (r 5 0.83 and 0.62 for 3 months; r 5 0.86 and 0.67 for 45 days) and the House index (r 5 0.85 and 0.79 for 3 months; r 5 0.79 and 0.74 for 45 days). Early warning based on these forecasting models can assist health authorities to improve vector control.

Forecasting models were developed for predicting Aedes aegypti larval indices in an endemic area for dengue (cities of Tartagal and Orán, northwestern Argentina), based on the Breteau and House indices and environmental variables considered with and without time lags. Descriptive models were first developed for each city and each index by multiple linear regressions, followed by a regional model including both cities together. Finally, two forecasting regional models (FRM) were developed and evaluated. FRM2 for the Breteau index and House index fit the data significantly better than FRMI. An evaluation of these models showed a higher correlation FRM1 than for FRM2 for the Breteau index (r = 0.83 and 0.62 for 3 months; r = 0.86 and 0.67 for 45 days) and the House index (r = 0.85 and 0.79 for 3 months; r = 0.79 and 0.74 for 45 days). Early warning based on these forecasting models can assist health authorities to improve vector control.

Food competition in the larval phase of Culex pipiens quinquefasciatus and its effect on the adult stage was experimentally studied under laboratory conditions. Cohorts with different densities of initial first instar larvae (from 50 to 4000 individuals per g of food) were followed until adult emergence, including egg laying. The number of individuals in the cohorts were counted every two days, until all adults emerged. Adult females were fed every four days. Surviving adults and eggs laid were counted daily. The proportion of adult females, adult weight, and female fertility decreased as larval density increased. Adult longevity and female fecundity did not show a density dependent change. The generation time increased and the realized rate of natural increase and net rate of increase showed a negative relationship with larval density. Resumen. Se estudió experimentalmente el efecto de la competencia por alimento era la fase larval de Culex pipiens quinquefasciatus y su efecto sobre el estado adulto, bajo condiciones de laboratorio. Cohortes con diferente densidad inicial de larvas de primer estadio (desde 50 a 4000 individuos por gramo de comida) fueron estudiadas hasta la emergencia de adultos, incluyendo la postura de huevos. El número de individuos en las cohortes fue contado cada dos días, hasta que todos los adultos emergieron. Las hembras adultas fueron alimentadas cada cuatro días. Los adultos sobrevivientes y los huevos puestos fueron contados diariamente. La proporción de hembras adultas, el peso de adultos y la fertilidad de hembras disminuyeron a medida que la densidad larval aumentó. La longevidad de adultos y la fecundidad de hembras no mostró un cambio densodependiente. El tiempo generacional se incrementó y la tasa intrínseca de crecimiento natural y la tasa neta de incremento mostraron una relación negativa con la densidad larval.

Forecasting models were developed for predicting Aedes aegypti larval indices in an endemic area for dengue (cities of Tartagal and Orá n, northwestern Argentina), based on the Breteau and House indices and environmental variables considered with and without time lags. Descriptive models were first developed for each city and each index by multiple linear regressions, followed by a regional model including both cities together. Finally, two forecasting regional models (FRM) were developed and evaluated. FRM 2 for the Breteau index and House index fit the data significantly better than FRM 1. An evaluation of these models showed a higher correlation FRM 1 than for FRM 2 for the Breteau index (r 5 0.83 and 0.62 for 3 months; r 5 0.86 and 0.67 for 45 days) and the House index (r 5 0.85 and 0.79 for 3 months; r 5 0.79 and 0.74 for 45 days). Early warning based on these forecasting models can assist health authorities to improve vector control.

Environmental variables are some of the factors that more impact on Aedes aegypti, vector of Dengue, Chikungunya and Zika viruses. In this study, the Ae. aegypti oviposition activity was related to satellite and meteorological variables, in Córdoba City (Argentina). Eggs were collected using ovitraps placed throughout the city from 2009 to 2012, replaced them weekly. Generalized Linear Mixed Models were developed with negative binomial distributions of errors, modeling average number of eggs collected weekly as a function of satellite and meteorological variables with time lags. The best model included a vegetation index, vapor pressure of water, precipitation and photoperiod, lagged between 3 and 4 weeks. By each increment unit in vegetation index, vapor pressure (hPa) and light hour, the average number of eggs increases by 72%, 20% and 29%, respectively, in the following 3 or 4 weeks. In addition, the average number of eggs decreases a 50% in the following month by each millimeter...

The list of twenty-two species of Culicidae from the southern coast of Mar Chiquita Lake is extended to twenty-eight.  Aedeomyia squamipennis  (Lynch Arribalzaga) , Culex acharistus  Root,  Culex chidesteri  Dyar,  Haemagogus spegazzinii  Brethes  , Mansonia titillans  (Walker) and  Psorophora holmbergi  Lynch Arribalzaga are listed for the first time for the region. The available information on sanitary importance of the culicids of the area is summarized