Seroepidemiological study of Toxoplasma gondii infections in equids in Europe

Authors: CANO-TERRIZA, DAVID - Universidad De Cordoba; FRANCO, JUAN - Eurofins - Ingenasa; JOSE-CUNILLERAS, EDUARD - Autonomous University Of Barcelona; BUONO, FRANCESCO - The University Of Naples Federico Ii; ALMERIA, SONIA - Food And Drug Administration(FDA); VENEZIANO, VINCENZO - The University Of Naples Federico Ii; ALGUACI, EDUARDO - Uplands Way Vet Clinic; GARCIA, JESUS - Fethard Equine Hospital; VILLENA, ISABELLE - National Reference Center For Toxoplasmosis; Dubey, Jitender; JIMÉNEZ-MARTÍN, DEBORA - Universidad De Cordoba; GARCIA-BOCANEGRA, IGNACIO - Universidad De Cordoba

Submitted to: Zoonoses and Public Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/6/2023
Publication Date: 1/23/2023
Citation: Cano-Terriza, D., Franco, J., Jose-Cunilleras, E., Buono, F., Almeria, S., Veneziano, V., Alguaci, E., Garcia, J., Villena, I., Dubey, J.P., Jiménez-Martín, D., Garcia-Bocanegra, I. 2023. Seroepidemiological study of Toxoplasma gondii infections in equids in Europe. Zoonoses and Public Health. 70(3):276-283. https://doi.org/10.1111/zph.13026.
DOI: https://doi.org/10.1111/zph.13026

Interpretive Summary: Food safety is a worldwide concern. Among these zoonotic pathogens, the single-celled parasite Toxoplasma gondii is perhaps the most ubiquitous, having been identified in virtually all warm- blooded animals and humans. Toxoplasma gondii can cause serious illness in humans and animals, including birth defects. Humans become infected postnatally by eating undercooked meat infected with T. gondii tissue cysts or by ingesting oocysts from the environment excreted in cat feces. In several countries, especially Europe, horse meat is eaten by people often undercooked. Thus, the ingestión of infected horse meat is a known source of toxoplasmosis in humans. Additionally, raw donkey milk is also consumed by humans and T. gondii DNA has been found in donkey milk. In the present study, authors found a widespread distribution of T. gondii among equid populations in different European countries. This research will be of interest to public health community, equine breeders, and parasitologists. The USDA contribution to this study was completed before 2019, before the redirection of Toxoplasma research at the USDA.

Technical Abstract: Toxoplasmosis caused by the obligate intracellular protozoan Toxoplasma gondii is a worldwide parasitic zoonosis common among humans and animals. A cross-sectional study was carried out to determine the exposure to T. gondii in equids in Europe. Serum samples from 1399 equids (1085 horses, 238 donkeys and 76 mules/hinnies) bred in European countries were collected during the period 2013-2021. The overall seroprevalence of T. gondii was 18.9% (CI95%: 16.9–21.0) by using the modified agglutination test (MAT) at a cut-off of 1:25. Seropositivity by country was 27.1% in Italy, 16.6% in Spain, 12.0% in United Kingdom and 7.0% in Ireland. Anti-T. gondii antibodies were detected in 12.8% horses, 43.7% donkeys, and in 28.9% mules/hinnies. The risk for being seropositive for T. gondii was 5.3 and 2.7 times higher in donkeys and mules/hinnies than in horses, respectively. In addition, significantly higher seropositivity was observed in horses from herds that disinfected less than once a week (13.9%; p = 0.038, OR = 1.6; CI95%: 1.03–2.62) compared to those from herds that performed weekly disinfection of the facilities (9.4%). This is the first large-scale survey on T. gondii comprising horses, donkeys, and mules/hinnies in Europe and the first report of T. gondii exposure in horses from Ireland and UK. We found a widespread distribution of T. gondii among equid populations in different European countries. The seroprevalence found in these species, especially in donkeys and mules/hinnies, highlights the potential risk of human infection through the consumption of their raw/undercooked milk or meat.