Recipient Organization
TEXAS A&M UNIVERSITY
750 AGRONOMY RD STE 2701
COLLEGE STATION,TX 77843-0001
Performing Department
Entomology
Non Technical Summary
Pathogens at the human-animal interface continue to emerge and threaten both human and animal health. Increased urbanization, globalization, and climate change have facilitated the transmission of multiple infectious agents, especially those vectored by arthropods. Our research team has been studying the transmission of pathogens by mosquitoes, triatomines, fleas, and ticks in communities in Texas and Mexico. These arthropods are responsible for the transmission of a large suite of viral, bacterial, and protozoan parasites such as West Nile virus (WNV), Dengue virus (DENV), Trypanosoma cruzi (causing Chagas disease), and Rickettsia spp. (causing murine typhus and Rocky Mountain spotted fever). With the proliferation of domestic animals in the peridomestic environment, arthropods have the opportunity to feed on both animals and humans in close proximity, as our past studies have documented (Curtis-Robles et al. 2018, Olson et al. 2020). With limited vaccines and treatment options available for these agents, vector control is the prime approach for reducing human and animal disease. Existing tools for arthropod vector control are limited or ineffective. One intervention approach gaining attention is with host-targeted insecticides, or endectocides, which deliver insecticidal products to humans or animals which then kill endo- and ectoparasites (Daniels et al. 1991, Pound et al. 2000, Hoen et al. 2009). This vector control approach has proven effective for a limited number of applications such as human malaria and WNV and is being evaluated for use with wild and domestic animals (Chaccour et al. 2013, Drexler et al. 2014, Nguyen et al. 2019, Alvarez-Hernandez et al. 2020). Our project goal is to target high-risk communities suffering from multiple vector-borne disease agents with endectocides given to animals, killing multiple arthropods that feed on them, and thus improving human and animal health. To reach this goal we need to identify anti-parasitic products effective at killing disease vectors and in the case of livestock, minimal chemical withdrawal periods to allow human consumption of animals or products. This will require working with industry partners to add new arthropods to the label of existing products, development of new product formulations for targeted delivery, or new products with different active ingredients. The end goal being an integrated One Health project targeting multiple domestic and wild animal species in the domestic and peridomestic environment to suppress populations of disease vectors.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Goals / Objectives
Our project goal is to target high-risk communities suffering from multiple vector-borne disease agents with endectocides given to animals, killing multiple arthropods that feed on them, and thus improving human and animal health. To reach this goal we need to identify anti-parasitic products effective at killing disease vectors and in the case of livestock, minimal chemical withdrawal periods to allow human consumption of animals or products. This will require working with industry partners to add new arthropods to the label of existing products, development of new product formulations for targeted delivery, or new products with different active ingredients. The end goal being an integrated One Health project targeting multiple domestic and wild animal species in the domestic and peridomestic environment to suppress populations of disease vectors.
Project Methods
Preliminary DataOur prior work has identified the vertebrate host feeding patterns of important disease vectors using bloodmeal analysis techniques. Across datasets from both mosquitoes (Hamer et al. 2009, Olson et al. 2020) and triatomines (Curtis-Robles et al. 2018), we note that bloodmeals are commonly taken from both dogs and chickens, in addition to humans. With support from the American Kennel Club, we have evaluated existing canine veterinary endectocides labeled for tick and flea control to determine their ability to kill triatomines. Dogs were given these products: Bravecto (fluralaner), Credelio (lotilaner), Ivermectin, and combinations of these drugs) and blood was sampled at 0, 7, 30, and 45 days. The blood was fed to triatomines and survival was monitored for one-week post-exposure. The results show that most of these products labeled for other ectoparasites are also effective at killing triatomine vectors (Figure 1).ApproachTo build on this work with canine systemic insecticides and triatomines, we propose to identify poultry products that can kill triatomines and mosquitoes. Alternative and organic poultry production systems are increasing globally in diverse communities (Jeni et al. 2021). Many studies have documented chicken feeding by triatomines in Arizona (Behrens-Bradley et al. 2020) and Texas (Curtis-Robles et al. 2018). A primary triatomine vector species in Central America is Triatoma dimidiata, which routinely takes blood meals from chickens (Zeledón et al. 1973, Monroy et al. 2003, Catala et al. 2004). Because many homes in Latin American communities have chickens that propagate T. dimidiata populations, there is an elevated risk of transmission of T. cruzi in these areas (Catala et al. 2004). An integrated vector control campaign with residual insecticides and rodent removals decreased the vector populations by 10.6 fold (De Urioste-Stone et al. 2015). Our goal is to complement existing control tools with the integration of endectocide treatment of domestic animals in these communities.Culex spp. mosquitoes are also ornithophilic in their feeding habits, frequently taking bloodmeals from domestic chickens (Tempelis et al. 1965, Thiemann et al. 2012, Estrada-Franco et al. 2020, Olson et al. 2020). Recently a study at Colorado State University has been developing a method to deliver ivermectin-treated food to chickens or wild birds for the control of Culex tarsalis, a primary vector of WNV (Nguyen et al. 2019). This approach could be applied to multiple systems and potentially in an integrated approach simultaneously reducing several arthropod vectors, including kissing bugs, mosquitoes, ticks, and fleas. We aim to initiate this work with an evaluation of systemic insecticides delivered to chickens on the efficacy of killing kissing Triatoma gerstaeckeri and Culex quinquefasciatus mosquitoes. We will test two insecticides that are approved for use in poultry: Exzolt (active ingredient: fluralaner) (Huyghe et al. 2017) and HITEK (active ingredient: ivermectin). We hypothesize that these systemic poultry insecticides will have a detrimental effect on triatomine and mosquito survivorship. This multi-target One-health approach would improve the health for both humans and animals by reducing suppressing vector abundance so that fewer vectors will transmit pathogens to humans and animals.Research ObjectivesIdentify what effect the systemic poultry insecticides Exzolt and HITEK have on Triatoma gerstaeckeri survivorship.Identify what effect the systemic poultry insecticides Exzolt and HITEK have on Culex quinquefasciatus mosquito survivorship.MethodsTo test our hypotheses, we will utilize adult chickens housed in the Department of Poultry Sciences, Poultry Science Center. Chickens will be treated with an insecticide, per label instructions. The chickens will be transported to our Arthropod Containment Level 2 Insectary in Veterinary Medical Park to allow either triatomines or mosquitoes to directly feed on them. We have current IACUC approval for feeding mosquitoes and triatomines on chicks and the 3-year annual review submission of a full AUP describes all the animal use aspects of this current proposal, including housing location in the Poultry Science Center. Triatomines and mosquitoes will be allowed to feed on one of three treatments: HITEK treated chickens, Exzolt treated chickens, or control chickens not treated with anything. Feeding events will occur at 1 week, 1 month, 2 months, and 4 months post-treatment with each endectocide. After each feeding event, all kissing bugs and mosquitoes obtaining a blood meal will be monitored daily for 10 days, and their survivorship will be recorded.