Toxoplasma gondii prevalence in carnivorous wild birds in the eastern United States

Sawsan Ammar; Liberty Wood; Chunlei Su; Maria Spriggs; Justin Brown; Kyle Van Why; Richard Gerhold

doi:10.1016/j.ijppaw.2021.04.010

Toxoplasma gondii prevalence in carnivorous wild birds in the eastern United States

Int J Parasitol Parasites Wildl. 2021 Apr 25:15:153-157. doi: 10.1016/j.ijppaw.2021.04.010. eCollection 2021 Aug.

Authors

Sawsan Ammar^{1

2}, Liberty Wood¹, Chunlei Su³, Maria Spriggs⁴, Justin Brown⁵, Kyle Van Why⁶, Richard Gerhold¹

Affiliations

¹ Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, 2407 River Drive, Knoxville, TN, 37996, USA.
² Department of Clinical Pathology, Faculty of Veterinary Medicine, Sadat City University, Sadat City, Menofia, 32511, Egypt.
³ Department of Microbiology, University of Tennessee, 307 Ken and Blaire Mossman Bldg., 1311 Cumberland Avenue, Knoxville, TN, 37996, USA.
⁴ SeaWorld Parks & Entertainment, Busch Gardens, 3605 E. Bougainvillea Avenue, Tampa, FL, 33612, USA.
⁵ Department of Veterinary and Biomedical Sciences, Pennsylvania State University, State College, 110 Research Unit A. University Park, Pennsylvania, 16802, USA.
⁶ USDA APHIS Wildlife Services, Harrisburg, PA, 17106, USA.

Abstract

Toxoplasma gondii is an important zoonotic protozoan parasite that can infect all warm-blooded animals including mammals and birds. Raptors can be intermediate hosts for T. gondii and the infection may be dependent on their feeding habits. In this study, we investigated the seroprevalence of T. gondii in ten raptor species from Florida, Pennsylvania, and Tennessee followed by a parasite bioassay on select seropositive samples. From a total of 155 raptors, we detected T. gondii antibodies using a modified agglutination test (cutoff 1:25) in 32 (20.6%) birds. The T. gondii seroprevalence was 44.8% in Falconiformes (13/29), 75% in Strigiformes (15/20), and 3.8% in Ciconiiformes (4/106). All Ciconiiformes samples (hearts and sera) were collected from Pennsylvania during nuisance wildlife removal projects and all birds were apparently healthy. Falconiform and Strigiform samples were collected from an exotics clinic in Tennessee and a rehabilitation center in Florida. All sampled birds were dead or euthanatized due to failure of rehabilitation or treatment. There was no statistically significant difference in T. gondii seroprevalence between Tennessee and Florida in the tested raptors. There was also no statistically significant difference in T. gondii exposure between males and females or adults and subadults. Mice bioassay attempts using fresh brain and/or heart tissue were performed on four seropositive birds. We isolated viable T. gondii tachyzoites from one red-shouldered hawk (Buteo lineatus) and genotyped the isolate using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of ten genetic markers. The isolated strain was designated as TgHawkFL1, which is ToxoDB PCR-RFLP genotype #28. Further research is needed to investigate the prevalence of T. gondii in raptors in the United States to obtain a better understanding of the life cycle, wildlife population impacts, and transmission dynamics of the parasite.

Keywords: Genotyping; Modified agglutination; Protozoa; Raptors; Toxoplasma gondii.