High Level of Vector Competence of Aedes aegypti and Aedes albopictus from Ten American Countries as a Crucial Factor in the Spread of Chikungunya Virus

Abstract

Chikungunya virus (CHIKV) causes a major public health problem. In 2004, CHIKV began an unprecedented global expansion and has been responsible for epidemics in Africa, Asia, islands in the Indian Ocean region, and surprisingly, in temperate regions, such as Europe. Intriguingly, no local transmission of chikungunya virus (CHIKV) had been reported in the Americas until recently, despite the presence of vectors and annually reported imported cases. Here, we assessed the vector competence of 35 American Aedes aegypti and Aedes albopictus mosquito populations for three CHIKV genotypes. We also compared the number of viral particles of different CHIKV strains in mosquito saliva at two different times postinfection. Primarily, viral dissemination rates were high for all mosquito populations irrespective of the tested CHIKV isolate. In contrast, differences in transmission efficiency (TE) were underlined in populations of both species through the Americas, suggesting the role of salivary glands in selecting CHIKV for highly efficient transmission. Nonetheless, both mosquito species were capable of transmitting all three CHIKV genotypes, and TE reached alarming rates as high as 83.3% and 96.7% in A. aegypti and A. albopictus populations, respectively. A. albopictus better transmitted the epidemic mutant strain CHIKV_0621 of the East-Central-South African (ECSA) genotype than did A. aegypti, whereas the latter species was more capable of transmitting the original ECSA CHIKV_115 strain and also the Asian genotype CHIKV_NC. Therefore, a high risk of establishment and spread of CHIKV throughout the tropical, subtropical, and even temperate regions of the Americas is more real than ever.

Invasiveness ofAedes aegyptiandAedes albopictusand Vectorial Capacity for Chikungunya Virus

“…This confirms that salivary glands may act as an anatomical barrier to virus transmission and may vary with mosquito and viral genetics, as well as viral dose [44]. Nonetheless, transmission efficiency reached rates as high as 83% and 97% in A. aegypti and A. albopictus populations, respectively [45].…”

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].…”

Rapid selection against arbovirus-induced apoptosis during infection of a mosquito vector

“…This species is the major vector for yellow fever and dengue viruses, which alone are responsible for more than 100 million infections and 50,000 deaths worldwide per year (1,2). A. aegypti is also an important vector for chikungunya virus, an emerging pathogen in South Asia, Africa, Europe, and more recently the Caribbean region (3). The range of A. aegypti is broad, including tropic and subtropic regions around the world, and it primarily lives in close association with humans, making it an especially problematic disease vector (4)(5)(6).…”