Experimental toxoplasmosis in elk (Cervus canadensis)

Area of Science:

• Veterinary Parasitology
• Wildlife Diseases
• Immunology

Background:

• Toxoplasma gondii is a significant protozoan parasite with a wide host range.
• Understanding T. gondii transmission and pathogenesis in wildlife, such as elk, is crucial for ecological and public health.
• Elk are potential reservoirs for T. gondii, impacting ecosystems and potentially livestock.

Purpose of the Study:

• To investigate the susceptibility of elk to Toxoplasma gondii infection.
• To determine the serological and pathological responses of elk following experimental T. gondii inoculation.
• To assess the potential for T. gondii transmission from infected elk to other animals.

Main Methods:

• Two elk, a pregnant cow and a calf, were experimentally infected with T. gondii oocysts.
• Antibody responses were monitored using Sabin-Feldman dye test and indirect hemagglutination assays.
• Tissues from infected elk and fetus were inoculated into mice and cats to isolate T. gondii.

Main Results:

• Both elk developed T. gondii antibodies, confirmed by serological tests.
• The fetus of the infected cow also showed a positive antibody titer.
• T. gondii was successfully isolated from various tissues of the infected elk and the fetus.
• Infected elk and calf remained clinically asymptomatic throughout the study period.

Conclusions:

• Elk are susceptible to T. gondii infection, developing a detectable immune response.
• The parasite can disseminate to multiple tissues in elk, including the fetus.
• Asymptomatic infection in elk poses a challenge for disease surveillance and control.
• Infected elk can serve as a source of infection for intermediate and definitive hosts.