Spatial Patterns of High Aedes aegypti Oviposition Activity in Northwestern Argentina

Aedes aegypti (L.) (Diptera: Culicidae), the main vector of dengue and urban yellow fever in the world, is highly adapted to the human environment. Artificial containers are the most common larval habitat for the species, but it may develop in tree holes and other phytotelmata. This study assessed whether tree holes in San Ramón de la Nueva Orán, a city located in subtropical montane moist forest where dengue outbreaks occur, are relevant as larval habitat for Ae. aegypti and if the species may be found in natural areas far from human habitations. Water holding tree holes were sampled during 3 years once a month along the rainy season using a siphon bottle, in urban and suburban sites within the city and in adjacent forested areas. Larvae and pupae were collected and the presence and volume of water in each tree hole were recorded. Finding Ae. aegypti in forested areas was an isolated event; however, the species was frequently collected from tree holes throughout the city and along the sampling period. Moreover, larvae were collected in considerably high numbers, stressing the importance of taking into account these natural cavities as potential reinfestation foci within dengue control framework.

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“…No significant differences ( P = 0.67) were detected either regarding oviposition activity sectors based on Estallo et al . (2013).…”

Section: Resultsmentioning

confidence: 99%

“…Estallo et al . (2013) analyzed the spatial patterns of Ae. aegypti oviposition activity and identified hot spot areas in central and southern regions of Orán city.…”

Section: Methodsmentioning

confidence: 99%

Tree holes as larval habitats forAedes aegyptiin urban, suburban and forest habitats in a dengue affected area

Mangudo

Aparicio

Gleiser

2015

Bull. Entomol. Res.

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“…Aedes (Stegomyia) aegypti is well known as the main vector of dengue [ 1 ], widely distributed from tropical to subtropical areas of the world [ 2 ]. In Argentina, it reaches central temperate regions of the country [ 3 – 5 ], although eggs have also been found in the Patagonia region (Neuquén Province) [ 6 ].…”

Section: Introductionmentioning

confidence: 99%

“…aegypti oviposition activity has also been developed for Oran, which enabled a predictive map with areas of maximum probability of Ae . aegypti oviposition activity and high risk areas of transmission [ 5 ].…”

Section: Introductionmentioning

confidence: 99%

Weather Variability Associated with Aedes (Stegomyia) aegypti (Dengue Vector) Oviposition Dynamics in Northwestern Argentina

et al. 2015

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This study aims to develop a forecasting model by assessing the weather variability associated with seasonal fluctuation of Aedes aegypti oviposition dynamic at a city level in Orán, in northwestern Argentina. Oviposition dynamics were assessed by weekly monitoring of 90 ovitraps in the urban area during 2005-2007. Correlations were performed between the number of eggs collected weekly and weather variables (rainfall, photoperiod, vapor pressure of water, temperature, and relative humidity) with and without time lags (1 to 6 weeks). A stepwise multiple linear regression analysis was performed with the set of meteorological variables from the first year of study with the variables in the time lags that best correlated with the oviposition. Model validation was conducted using the data from the second year of study (October 2006- 2007). Minimum temperature and rainfall were the most important variables. No eggs were found at temperatures below 10°C. The most significant time lags were 3 weeks for minimum temperature and rains, 3 weeks for water vapor pressure, and 6 weeks for maximum temperature. Aedes aegypti could be expected in Orán three weeks after rains with adequate min temperatures. The best-fit forecasting model for the combined meteorological variables explained 70 % of the variance (adj. R2). The correlation between Ae. aegypti oviposition observed and estimated by the forecasting model resulted in rs = 0.80 (P < 0.05). The forecasting model developed would allow prediction of increases and decreases in the Ae. aegypti oviposition activity based on meteorological data for Orán city and, according to the meteorological variables, vector activity can be predicted three or four weeks in advance.

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“…Prior studies in the subtropical northwest region of Argentina revealed a year-round vector population in areas with an annual mean temperature around 20°C. A low number of eggs was recorded during the winter season, and peak in oviposition was detected during summer months (December to March in the southern hemisphere) [21–24]. Studies from the temperate central areas, like Buenos Aires [25–29] and Córdoba provinces [30–32], found that oviposition discontinued during the winter months due to low temperatures (below 17°C), with a peak in Ae.…”

Section: Introductionmentioning

confidence: 99%

A decade of arbovirus emergence in the temperate southern cone of South America: dengue,Aedes aegyptiand climate dynamics in Córdoba, Argentina

Estallo

Sippy

Stewart-Ibarra

et al. 2020

Preprint

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Background: Argentina is located at the southern temperate range of arboviral transmission by the mosquito Aedes aegypti and has experienced a rapid increase in disease transmission in recent years. Here we present findings from an entomological surveillance study that began in Cordoba, Argentina, following the emergence of dengue in 2009. Methods: From 2009 to 2017, larval surveys were conducted monthly, from November to May, in 600 randomly selected households distributed across the city. From 2009 to 2013, ovitraps (n=177) were sampled weekly to monitor the oviposition activity of Ae. aegypti. We explored seasonal and interannual dynamics of entomological variables and dengue transmission. Cross correlation analysis was used to identify significant lag periods. Results: Aedes aegypti were detected over the entire study period, and abundance peaked during the summer months (January to March). We identified a considerable increase in the proportion of homes with juvenile Ae. aegypti over the study period (from 5.7% of homes in 2009-10 to 15.4% of homes in 2016-17). Aedes aegypti eggs per ovitrap and larval abundance were positively associated with temperature in the same month. Autochthonous dengue transmission peaked in April, following a peak in imported dengue cases in March; autochthonous dengue was not positively associated with vector or climate variables. Conclusions: This longitudinal study provides insights into the complex dynamics of arbovirus transmission and vector populations in a temperate region of arbovirus emergence. Our findings suggest that Cordoba is well suited for arbovirus disease transmission, given the stable and abundant vector populations. Further studies are needed to better understand the role of regional human movement.

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Spatial Patterns of High Aedes aegypti Oviposition Activity in Northwestern Argentina

Cited by 13 publications

References 18 publications

Tree holes as larval habitats forAedes aegyptiin urban, suburban and forest habitats in a dengue affected area

Tree holes as larval habitats forAedes aegyptiin urban, suburban and forest habitats in a dengue affected area

Weather Variability Associated with Aedes (Stegomyia) aegypti (Dengue Vector) Oviposition Dynamics in Northwestern Argentina

A decade of arbovirus emergence in the temperate southern cone of South America: dengue,Aedes aegyptiand climate dynamics in Córdoba, Argentina

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