Israeli Spotted Fever, Tunisia

Epidemiologic investigation of our case-patients that included questioning relatives, patients, and butchers found that eating raw horse meat imported from Canada (patient 1) or Brazil (patient 2) was the most likely source of the parasites. The geographic origin of the horse meat eaten by patient 3 is unknown. Moreover, an atypical T. gondii strain was isolated after mouse inoculation with horse meat from the fi rst patient’s butcher. In all 3 cases, close relatives encouraged the patients to eat raw horse meat regularly because the practice is traditionally thought to reinforce health. Human toxoplasmosis cases associated with horse meat consumption are rarely reported but are probably underestimated (2). In the European Union, France and Italy account for more than two thirds of all horse meat eaten, predominantly raw, thereby increasing the likelihood of infection by various parasites, including Trichinella spp. and Toxoplasma spp. (4). Under natural conditions, serologic prevalence of T. gondii parasites in horses worldwide may range from 0% to 80% (5). Many factors could account for this variation, including the sensitivity and specifi city of the serologic test, ages of animals, geographic area and hygienic condition of farm management (5). The only prevalence survey of horses slaughtered for food that we are aware of was conducted in Canada and the United States and found antibodies to T. gondii parasites in 124 (6.9%) of 1,788 serum samples (6). T. gondii tissue cysts in meat are immediately killed by reaching an internal temperature of 67°C in all parts of meat during cooking (7). Deep freezing (<–12°C for at least 3 days) of meat before cooking is recommended because it reduces the risk for infection by inactivating most tissue cysts (7). These precautions are often not applied to horse meat because these imported carcasses are usually shipped as “fresh meat” and frequently eaten raw. Eating raw horse meat imported from non-European countries may expose consumers to high inocula of highly virulent atypical Toxoplasma spp. strains, which may cause life-threatening primary infection (case-patient 1) or severe congenital toxoplasmosis with atypical outcome of acquired toxoplasmosis in the mother (case-patient 3). Risk assessment for toxoplasmosis from horses slaughtered for food and imported into the European Union, as was recently done in France for ovine meat, is urgently needed (3).