At a Glance
Researches at Colorado State University have developed and implemented a localized control method for West Nile Virus that can be translated to any of the numerous arboviruses that exist in avian reservoirs worldwide. The strategy is to treat bird feed with endectocidal drugs (e.g. ivermectin) and put it into bird feeders that can be placed in backyards, parks, ranches or farms, and any other places in the environment so that the feed can be ingested by local birds. The bird feed and feeders are designed to attract bird species that are often bitten by arbovirus vector insects (e.g. Culex tarsalis mosquitoes), allowing the birds to develop high levels of endectocide in their blood. When bitten, these insects will have reduced survival or other physiological impairment – altering the population structure and biological traits of the arbovirus vectors; ultimately making them less able to transmit disease to humans and other animals.
West Nile virus (WNV) is an arthropod-borne flavivirus, and the leading cause of domestically acquired arboviral disease in the United States, resulting in significant disease and death every year in humans, domesticated animals, and wildlife. From 1999-20176, >485,000 cases of human WNV disease and >2000 deaths were reported to the CDC, but the total number of individuals in the U.S. who have been made ill from WNV is estimated to be greater than 1 million, or approximately 1 of every 5 persons infected (>5 million infected individuals).
Currently, control of WNV transmission remains focused on vector control through larvicide and adulticide applications. Larvicide applications are generally preferred to adulticide applications as they are more cost-effective and less environmentally-damaging due to more direct and efficient targeting of mosquitoes but the efficacy can vary significantly with suboptimal catch basin design or environmental conditions. Similarly, ground ultra-low volume application of adulticides may reduce target mosquito populations under ideal conditions, but studies have provided inconclusive data on their effect on WNV infection rates in mosquitoes or subsequent virus transmission. Furthermore, these Insecticide applications also often face community opposition due to environmental and toxicity/allergenicity concerns and are often restricted to urban and semi-urban communities that can afford to fund them.
- Allows for local arbovirus control in small areas and private land
- Treatment is safer for populations and the environment
- Cheaper and targeted in compared to current options
KM Holcomb, et al. (2022) Effects of ivermectin treatment of backyard chickens on mosquito dynamics and West Nile virus transmission. PLoS Neglected Tropical Diseases, Public Library of Science https://doi.org/10.1371/journal.pntd.0010260.
C Nguyen, et al. (2019) Evaluation of a Novel West Nile Virus Transmission Control Strategy That Targets Culex Tarsalis with Endectocide-Containing Blood Meals. PLoS Neglected Tropical Diseases, Public Library of Science. www.ncbi.nlm.nih.gov/pubmed/30845250.
Last updated: April 2022