Lamb as a potential source of Toxoplasma gondii infection for Australians

Authors: DAWSON, ABBY - Flinders University; ASHANDER, LIAM - Flinders University; APPUKUTTAN, BINOY - Flinders University; WOODMAN, RICHARD - Flinders University; Dubey, Jitender; WHILEY, HARRIET - Flinders University; SMITH, JUSTINE - Flinders University

Submitted to: Australian and New Zealand Journal of Public Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2019
Publication Date: 1/31/2020
Citation: Dawson, A.C., Ashander, L.M., Appukuttan, B., Woodman, R.J., Dubey, J.P., Whiley, H., Smith, J.R. 2020. Lamb as a potential source of Toxoplasma gondii infection for Australians. Australian and New Zealand Journal of Public Health. 44(1):49-52. https://doi.org/10.1111/1753-6405.12955.
DOI: https://doi.org/10.1111/1753-6405.12955

Interpretive Summary: Toxoplasma gondii infection is widely prevalent in humans and animals, and toxoplasmosis continues to be a public health concern worldwide, including the USA. Humans become infected postnatally by ingesting infected uncooked/undercooked meat or food and water contaminated with oocysts excreted by cats. Among the meat sources of T. gondii, lamb, and goat meat, and pork are considered important meat sources of T. gondii infection because beef and commercially raised poultry are rarely infected with T. gondii. Here, the authors found T. gondii DNA in 3 of 4 pooled samples of lamb from grocery stores in Australia. Results will be of interest to veterinarians, public health workers, and parasitologists.

Technical Abstract: Objective: Toxoplasmosis may follow consumption of undercooked meat containing Toxoplasma gondii cysts. Lamb is considered to pose the highest risk for contamination across meats. Red meat is often served undercooked, yet there are no current data on T. gondii contamination of Australian sourced and retailed lamb. We sought to address this gap in public health knowledge. Methods: Lamb mincemeat was purchased at the supermarket counter 3-times weekly for 6 months. T. gondii was detected by real-time polymerase chain reaction (PCR) of DNA extracted from the meat following homogenisation. Purchases were also tested for common foodborne bacterial pathogens. Results: Conservative interpretation of PCR testing (ie. parasite DNA detected in 3 of four tests) gave a probability of 43% (95% confidence interval, 32% – 54%) that lamb mincemeat was contaminated with T. gondii. None of the purchases were contaminated with Campylobacter jejuni, Salmonella species and S. enterica serovar Typhimurium, indicating sanitary meat processing. Conclusions: Australian lamb is commonly contaminated with T. gondii. Future studies should be directed at testing a range of red meats and meat cuts. Implications for Public Health: Consuming undercooked Australian lamb has potential to result in toxoplasmosis. There may be value in health education around this risk.