Persistence of encysted Toxoplasma gondii in tissues of equids fed oocysts.
Abstract: Thirteen 6-month- to 13-year-old equids were each inoculated orally with 10,000 infective Toxoplasma gondii oocysts. The equids remained clinically normal. Equids were euthanatized on postinoculation days 33, 45, 90, 104, 120, 140, 162, 183, 197, 204, 211, 294, and 476. Their tissues were bioassayed for viable oocysts by feeding muscles to Toxoplasma-free cats and by inoculation of pepsin digests of 13 organs into mice. Using mouse inoculation, T gondii was recovered from tissues of the 9 equids euthanatized on each of postinoculation days 33, 45, 120, 140, 183, 197, 211, 294, and 476. Toxoplasma gondii was isolated from the tongue and intestines of 4 equids, from the heart of 3 equids, from thigh muscles, brain, and heart of 2 equids, and from the eye, lungs, and spinal cord of 1 equid. Muscles from 9 of 13 equids were infectious to cats, as evidenced by feline shedding of oocysts. Results indicate that T gondii can persist in edible tissues of living equids up to 476 days and that non-cooked horsemeat should not be fed to cats or eaten by human beings.
Publication Date: 1985-08-01 PubMed ID: 4037503
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- Journal Article
Summary
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This research investigates how the Toxoplasma gondii parasite, which causes the disease toxoplasmosis, can maintain a presence in the tissues of horses even after 476 days of infection. It further advises against the consumption of undercooked horsemeat by cats and humans due to potential infection risks.
Experiment Setup
- Thirteen equids (a family of horses and related animals) aged between 6 months and 13 years were each orally exposed to 10,000 infective Toxoplasma gondii oocysts (a type of egg produced by the parasite).
- Throughout the study the equids showed no clinical signs of being unwell.
- The equids were euthanized at various intervals over a span of 476 post-inoculation days, and their tissues were used in bioassays to determine if the parasite was still present.
Results and Findings
- Oocysts were detected in various tissues of the equids at different post-inoculation stages, from as early as day 33 to as late as day 476.
- The Toxoplasma gondii parasite was found in different organs such as the tongue, intestines, heart, brain, thigh muscles, eye, lungs, and spinal cord of the equids.
- Cats fed on muscle tissue from 9 of the 13 euthanized equids became infected and exhibited shedding of the parasite’s oocysts.
Implications and Recommendations
- The research implies that the Toxoplasma gondii parasite can persist in an equid’s living tissues for up to 476 days. This suggests a significant potential risk for the transmission of the parasite to other live hosts.
- This risk raises concerns regarding the practice of feeding raw equid meat (horse meat in particular) to cats or humans, due to the potential for Toxoplasma gondii transmission.
- The study thus strongly advises against the consumption of raw or undercooked horse meat. Proper cooking of the meat can kill T. gondii, reducing the risk of transmission.
Cite This Article
APA
Dubey JP.
(1985).
Persistence of encysted Toxoplasma gondii in tissues of equids fed oocysts.
Am J Vet Res, 46(8), 1753-1754.
Publication
Researcher Affiliations
MeSH Terms
- Abattoirs
- Agglutination Tests / veterinary
- Animals
- Antibodies / analysis
- Horse Diseases / immunology
- Horse Diseases / parasitology
- Horses
- Mice
- Perissodactyla
- Toxoplasma / immunology
- Toxoplasma / isolation & purification
- Toxoplasmosis, Animal / immunology
- Toxoplasmosis, Animal / parasitology
Citations
This article has been cited 8 times.- Marzok M, Al-Jabr OA, Salem M, Alkashif K, Sayed-Ahmed M, Wakid MH, Kandeel M, Selim A. Seroprevalence and Risk Factors for Toxoplasma gondii Infection in Horses. Vet Sci 2023 Mar 22;10(3).
- Stelzer S, Basso W, Benavides Silván J, Ortega-Mora LM, Maksimov P, Gethmann J, Conraths FJ, Schares G. Toxoplasma gondii infection and toxoplasmosis in farm animals: Risk factors and economic impact. Food Waterborne Parasitol 2019 Jun;15:e00037.
- Klun I, Uzelac A, Villena I, Mercier A, Bobić B, Nikolić A, Rajnpreht I, Opsteegh M, Aubert D, Blaga R, van der Giessen J, Djurković-Djaković O. The first isolation and molecular characterization of Toxoplasma gondii from horses in Serbia. Parasit Vectors 2017 Apr 4;10(1):167.
- Aroussi A, Vignoles P, Dalmay F, Wimel L, Dardé ML, Mercier A, Ajzenberg D. Detection of Toxoplasma gondii DNA in horse meat from supermarkets in France and performance evaluation of two serological tests. Parasite 2015;22:14.
- Alvarado-Esquivel C, Pacheco-Vega SJ, Hernández-Tinoco J, Salcedo-Jáquez M, Sánchez-Anguiano LF, Berumen-Segovia LO, Rábago-Sánchez E, Liesenfeld O. Toxoplasma gondii infection in interstate truck drivers: a case-control seroprevalence study. Parasit Vectors 2015 Feb 5;8:77.
- VanWormer E, Fritz H, Shapiro K, Mazet JA, Conrad PA. Molecules to modeling: Toxoplasma gondii oocysts at the human-animal-environment interface. Comp Immunol Microbiol Infect Dis 2013 May;36(3):217-31.
- Dubey JP, Lindsay DS, Speer CA. Structures of Toxoplasma gondii tachyzoites, bradyzoites, and sporozoites and biology and development of tissue cysts. Clin Microbiol Rev 1998 Apr;11(2):267-99.
- Uggla A, Mattson S, Juntti N. Prevalence of antibodies to Toxoplasma gondii in cats, dogs and horses in Sweden. Acta Vet Scand 1990;31(2):219-22.
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