Dr. Andy Moorhead is a small animal parasitologist and Associate Professor at the University of Georgia, College of Veterinary Medicine. Dr. Moorhead received the DVM degree from North Carolina State University, followed by a MS in Veterinary Parasitology from Purdue University. He then received his Ph.D. degree from Cornell University. He became a Diplomate of the American College of Veterinary Microbiology (Parasitology) in 2015.
Filarial nematodes are important parasites in both human and animal health. In order to facilitate research on these parasites, we manage the Filariasis Research Reagent Resource Center (FR3), which maintains the life cycles of Brugia malayi, a causative agent of lymphatic filariasis (LF) in humans and animals, B. pahangi, a causative agent of LF in animals, and Dirofilaria immitis, the causative agent of canine heartworm disease. Blood from hosts is fed to mosquitoes, from which infectious third-stage larvae (L3s) are subsequently isolated. These L3s can then be used for experiments or be injected into subsequent hosts for the maintenance of infection. For example, when injected into the peritoneal cavity of the Mongolian jird, or gerbil (Meriones unguiculatus), L3s will develop into adult worms. This system is robust and allows the production of thousands of parasites a year, which are then shipped to researchers across North America and Europe. By having a centralized resource, the cost of maintenance of parasites is made insignificant to individual researchers who may not have either the dedicated insectary or animal space needed to produce these parasites, allowing for a reduction of animals used for parasite production.
As we maintain a system that very few researchers have, we can ask questions that other groups cannot. This drives our primary research interest, which is to understand the host specificity of filarial parasites, specifically in dogs, cats, and jirds. One large question that has not been sufficiently answered is, how does parasite X survive in host Y to establish and reproduce in tissue Z and cause disease? Furthermore, when is host specificity determined? Is the parasite life cycle blocked upon initial entry into the host, at the third to fourth larval stage molt, or when the parasite molts to become the juvenile adult? Our overall goal is to determine what host and nematode factors define the host specificity of filarial infections.
- Mattick J, Libro S, Bromley R, Chaicumpa W, Chung M, Cook D, Khan MB, Kumar N, Lau YL, Misra-Bhattacharya S, Rao R, Sadzewicz L, Saeung A, Shahab M, Sparklin BC, Steven A, Turner JD, Tallon LJ, Taylor MJ, Moorhead AR, Michalski M, Foster JM, Dunning Hotopp JC. X-treme loss of sequence diversity linked to neo-X chromosomes in filarial nematodes. PLoS Negl Trop Dis. 2021 Oct 27;15(10):e0009838. doi: 10.1371/journal.pntd.0009838. eCollection 2021 Oct. PMID: 34705823.
- Evans CC, Burkman EJ#, Dzimianski MT, Garner B, Moorhead AR. The course of Brugia malayimicrofilaremia in experimentally infected cats. Vector Borne Zoonotic Dis. 2021 Aug;21(8):586-592. doi: 10.1089/vbz.2020.2761. Epub 2021 Jun 14.PMID: 34129397.
- Evans, C.C., Day, K.M., Garner, B, Sakamoto, K., and R. Moorhead. A rapid, parasite-dependent cellular response to Dirofilaria immitis in the jird (Meriones unguiculatus). Parasit Vectors. 2021 Jan 7;14(1):25. doi: 10.1186/s13071-020-04455-x.PMID: 33413609.
- Savadelis, M.D.#, Dzimianski, M.T., Coleman, A.E., Rapoport, G.S., Sharma, A., Sakamoto, K., Keys, D., Ohmes, C.M., Hostetler, J.A., Zolynas, R., and R. Moorhead. Clinical assessment of heartworm-infected beagles treated with Advantage Multi®/Advocate® for dogs (imidacloprid + moxidectin) and doxycycline. J Vet Intern Med. 2020 Sep;34(5):1734-1745. doi: 10.1111/jvim.15853. Epub 2020 Jul 21.PMID: 32691900
- D. Savadelis#, C.C. Evans, K.H. Mabry, L.N. LeFavi, B.D. Klink, C. Simpson, A. R. Moorhead. Canine gastrointestinal nematode transmission potential in municipal dog parks in the southeast United States. Veterinary Parasitology: Regional Studies and Reports. 2019 Dec; 18.
- C. Evans, J.L. Bradner, M.D. Savadelis#, C.T. Nelson, A.R. Moorhead. Acetic acid as an alternative reagent in the modified Knott test. Veterinary Parasitology. 2019 Nov. 10.
- Savadelis M.D.#, Day K.M.#, Bradner J.L., Wolstenholme A.J., Dzimianski M.T., Moorhead A.R. Efficacy and side effects of doxycycline versus minocycline in the three-dose melarsomine canine adulticidal heartworm treatment protocol. Parasit Vectors. 2018 Dec 27;11(1):671. PMID: 30587225