Aedes aegyptifrom temperate regions of South America are highly competent to transmit dengue virus

Abstract

BackgroundAedes aegypti is extensively spread throughout South America where it has been responsible for large dengue epidemics during the last decades. Intriguingly, dengue transmission has not been reported in Uruguay and is essentially prevalent in subtropical northern Argentina which borders Uruguay.MethodsWe assessed vector competence for dengue virus (DENV) of Ae. aegypti populations collected in subtropical Argentina (Corrientes) as well as temperate Uruguay (Salto) and Argentina (Buenos Aires) in 2012 using experimental oral infections with DENV-2. Mosquitoes were incubated at 28°C and examined at 14 and 21 days p.i. to access viral dissemination and transmission. Batches of the Buenos Aires mosquitoes were also incubated at 15°C and 20°C.ResultsAlthough mosquitoes from temperate Uruguay and Argentina were competent to transmit DENV, those from subtropical Argentina were more susceptible, displaying the highest virus titters in the head and presenting the highest dissemination of infection and transmission efficiency rates when incubated at 28°C. Interestingly, infectious viral particles could be detected in saliva of mosquitoes from Buenos Aires exposed to 15°C and 20°C.ConclusionsThere is a potential risk of establishing DENV transmission in Uruguay and for the spread of dengue outbreaks to other parts of subtropical and temperate Argentina, notably during spring and summer periods.

Updating the geographical distribution and frequency of Aedes albopictus in Brazil with remarks regarding its range in the Americas

“…In Uruguay, a few Ae. albopictus were once detected near the Brazilian border, however subsequent efforts have failed to confirm the colonisation of the country by this species ( apud Lourenço-de-Oliveira et al 2013 ). Similarly, the occurrence of this mosquito in Bolivia, in South America, as previously suggested as infested by Benedict et al (2007) , has never been confirmed.…”

Quantifying the Contribution of Hosts with Different Parasite Concentrations to the Transmission of Visceral Leishmaniasis in Ethiopia

“…Equation (4) represents the infectiousness of a host with parasitemia, n , for a feeding vector. Note that equation (4) depends on two parameters (λ 1 , λ 2 ), which vary according to vector, host, disease type, and environmental parameters (e.g., temperature) [20] . This equation is our key result since it enables the calculation of the HIP from the distribution of host parasitemias.…”

Three-way interactions between mosquito population, viral strain and temperature underlying chikungunya virus transmission potential

“…Fully engorged females were transferred to cardboard cups and maintained on 10% sucrose in climatic chambers (KB 53, Binder, Tuttlingen, Germany) set at constant temperatures of 208C + 0.18C or 288C + 0.18C, with a 16 L : 8 D cycle and 70% relative humidity. A temperature of 208C was chosen as representative of the low-temperature threshold recorded when local CHIKV transmission occurred during the Italian epidemic between June and September 2007 [21,25] and in southeast France in September 2010 (http://www.meteociel.fr) [23], whereas 288C was chosen as a typical average temperature in tropical regions and has been commonly used in CHIKV vector competence assays [19,[26][27][28][29].…”