Location: Animal Parasitic Diseases LaboratoryTitle: Toxoplasma gondii infection in llama (Llama glama): acute visceral disseminated lesions, diagnosis, and development of tissue cysts) Author
Submitted to: Journal of Parasitology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/24/2014
Publication Date: 6/25/2014
Citation: Dubey, J.P., Newell, T., Verma, S., Edward, S. 2014. Toxoplasma gondii infection in llama (Llama glama): acute visceral disseminated lesions, diagnosis, and development of tissue cysts. Journal of Parasitology. 100:288-295. Interpretive Summary: Toxoplasmosis is a costly foodborne parasitic infection, of especially great concern to pregnant women and people with immune deficiency. Although infection is widely prevalent, only a minority of veterinary and human infections result in severe clinical disease. Of major interest is understanding the determinants to acute toxoplasmosis. Parasite genetics, host physiology, and host immune status are clearly important. Within this context, it is important to study pathogenesis when disease is severe, especially in hosts from which infection has not been previously reported. Here, we describe in detail a case of acute, fatal toxoplasmosis in a llama. It is the first report of disease in this animal, and a rare example of disease in camelids, to which llamas belong. Infection was disseminated throughout the animal, damaging many organs, including the heart (the suspected cause of death). This information will interest veterinarians, parasitologists, and all those concerned with the health effects of such foodborne parasites.
Technical Abstract: Clinical toxoplasmosis has been reported in many species of warm-blooded animals, but is rare in camelids. Here we report acute fatal systemic toxoplasmosis involving heart, thyroid gland, stomach, intestine, diaphragm, adrenal glands, and liver of a 13-mo-old llama (Llama glama). Many Toxoplasma gondii tachyzoites were associated with tissue necrosis in multiple organs. Death was attributed to severe myocarditis. Ulcers associated with numerous tachyzoites were present in the C3 compartment of the stomach. Tissue cyst development was followed using bradyzoite-specific T. gondii antibodies. Individual intracellular, and groups of 2 or more bradyzoites were identified in hepatocytes, biliary epithelium, myocardiocytes, lung, diaphragm, thyroid gland, spleen, and stomach. Lesions in the brain were few microglial nodules and very early tissue cysts containing 1-3 bradyzoites. These observations suggest that the animal acquired toxoplasmosis recently. Diagnosis was confirmed immunohistochemically by reaction with T. gondii-specific polyclonal rabbit serum but not with antibodies to the related protozoan Neospora caninum.