Feeding Host Range ofAedes albopictus(Diptera: Culicidae) Demonstrates Its Opportunistic Host-Seeking Behavior in Rural Singapore

Abstract

Aedes albopictus (Skuse) is a competent vector of arboviruses of public health importance, including dengue virus (DENV) and chikungunya virus viruses. Ae. albopictus is the primary vector of chikungunya virus in Singapore. However, despite being ubiquitous, it plays a secondary role in DENV transmission. The vectorial capacity of Ae. albopictus for DENV in field settings appears to be weak because dengue primarily occurs in Aedes aegypti (L.)-dominated, urban settings of the country. As host-seeking behavior is one of the determinants of vectorial capacity, we screened 6,762 female Ae. albopictus from rural, semiurban, and urban locations in Singapore for avian and nonavian bloodmeals using two polymerase chain reaction-sequencing assays developed in-house. The majority (83.2%, n = 79) of bloodmeals from rural and semiurban areas were from humans. However, Ae. albopictus was also found to feed on shrews, swine, dogs, cats, turtles, and multiple hosts in rural settings. In urban areas, all positive bloodmeals were from humans. There were no avian bloodmeals. Our findings testify that Ae. albopictus is highly anthropophagic even in rural settings, but become opportunistic in extremely low human abundance. This opportunistic feeding behavior warrants further investigations into the vectorial capacity of Ae. albopictus to assess its role in arbovirus transmission in endemic habitats.

Zika virus in Brazil and the danger of infestation by Aedes (Stegomyia) mosquitoes

“…albopictus mosquitoes in suburban areas of Singapore had fed on humans; but some were reactive to shrews, swine, dogs, cats, turtles, and other hosts in rural settings. In urban areas, all positive blood meals were from humans (85) .…”

Peridomestic Aedes malayensis and Aedes albopictus are capable vectors of arboviruses in cities

“…Aedes albopictus belongs to the same subgenus ( Stegomyia) and is considered a secondary vector of DENV and CHIKV [2], primarily because of its catholic feeding habits and peridomestic (defined here as city parks and green corridors interspersing housing estates) biology. Aedes albopictus mosquitoes will utilize oviposition sites distant from human habitats [5], but prefer humans as hosts even when other vertebrates are available [7]. This species is a biting nuisance [8, 9] and will enter houses and feed indoors [10, 11].…”

Defining the risk of Zika and chikungunya virus transmission in human population centers of the eastern United States

“…albopictus must bite humans at least 40% of the time. The Asian tiger mosquito's vectorial capacity is persistently questioned because the propensity for biting humans versus other vertebrates varies widely, as the species appears to opportunistically bite the most available vertebrates [19,20,26,[28][29][30][34][35][36][37]. We show that while a higher probability of human host-use is associated with greater R 0 , increasing the proportion of bites from humans above 40% increased potential for local transmission and resulting human disease.…”

“…albopictus is generally considered less important than Ae. aegypti for transmitting viral infections to humans because it has been shown to feed on a range of vertebrate species beyond human [18][19][20]. An Ae.…”