Aedes Taeniorhynchus Vectorial Capacity Informs A Pre-Emptive Assessment Of West Nile Virus Establishment In Galápagos

Abstract

Increased connectivity with the mainland has led to the arrival of many invasive species to the Galápagos Islands, including novel pathogens, threatening the archipelago's unique fauna. Here we consider the potential role of the mosquito Aedes taeniorhynchus in maintaining the flavivirus West Nile virus [WNV] should it reach the islands. We report on three components of vectorial capacity - vector competency, distributional abundance and host-feeding. In contrast to USA strains, Galápagos A. taeniorhynchus is a competent and efficient WNV vector, capable of transmission at 5 days post-exposure. Based on 25 blood-meals, mammalian feeding suggests a potential bridge vector role should contact with key amplification taxa occur. Vector population abundance is driven primarily by climatic factors, peaking between January and March. As a ubiquitous competent vector, A. taeniorhynchus may facilitate future WNV establishment, therefore it is vital to ensure the biosecurity of Galápagos to prevent introductions of pathogens such as WNV.

The vector ecology of introduced Culex quinquefasciatus populations, and implications for future risk of West Nile virus emergence in the Galápagos archipelago

“…() also report distributions of C. quinquefasciatus and A . taeniorhynchus on Isabela and Santa Cruz in 2012–2014, consistent with our current and earlier studies (Bataille et al ., , , , ; Eastwood et al ., ). The relative roles of human‐mediated transport, natural dispersal and local adaptation in the speed of establishment across the islands remain to be fully understood and are difficult to quantify due to a lack of historical monitoring for the presence of this mosquito.…”

“…prior to the rainy season commencing in January (and also prior to the abundance peak of the endemic mosquito species A. taeniorhynchus ; Eastwood et al ., ). This might be counterintuitive, since mosquito abundance might be expected to increase with precipitation, as it does for A. taeniorhynchus (Galardo et al ., ; Eastwood et al ., ). However, drought conditions elsewhere have been associated with increased number of blood‐fed Culex spp.…”

“…These data were similarly mapped geospatially over a digital elevation model of the Galápagos Islands, and determinants of mosquito abundance were assessed using detections from Santa Cruz Island (where more records were available), with predictive factors and modelling (with backward selection) as described by Eastwood et al . ().…”

“…It has been shown that an endemic Galápagos lineage of the black salt marsh mosquito, Aedes taeniorhynchus (Wiedemann) (Bataille et al ., ), is a competent WNV vector and both abundant and widespread across the archipelago (Eastwood et al ., ). However, Galápagos A. taeniorhynchus appears to have a low feeding rate on birds, suggesting that it might not be a primary concern for the establishment of WNV on Galápagos (Eastwood et al ., ). Conversely, Culex quinquefasciatus Say might be a more important candidate vector since the species is a key vector of WNV in the southern U.S.A. (Kramer et al ., ).…”

Analysis of the genetic variability and structure of Ochlerotatus taeniorhynchus (Diptera: Culicidae) populations from the Colombian Atlantic coast on the basis of random amplified polymorphic DNA markers

“…Specifically, typical epizootic VEEV strains of the subtypes IAB and IC are efficiently transmitted by this mosquito (Weaver et al, 2004). Additionally, this insect has also been identified as a competent vector of other arboviruses such as the Saint Louis encephalitis virus (Nayar et al, 1986), Eastern equine encephalitis virus (Ortiz et al, 2003), and West Nile virus (Eastwood et al, 2013). Furthermore, O. taeniorhynchus plays a major role in the transmission of the dog heartworm (Dirofilaria immitis) in South and Central America (Manrique-Saide et al, 2010).…”