Sarcocystosis from a One Health perspective: Revisiting zoonotic potential, transmission dynamics, clinical features,...

Sarcocystosis is an emerging zoonotic disease caused by apicomplexan parasites of the genus Sarcocystis, which can infect a wide range of hosts, including humans, animals, reptiles, and birds. Humans may serve as either definitive or intermediate hosts, depending on Sarcocystis species. Consumption of undercooked beef containing mature sarcocysts of Sarcocystis hominis or Sarcocystis heydorni, or of raw or partially cooked pork containing Sarcocystis suihominis zoitocysts, may lead to intestinal sarcocystosis in humans. In contrast, muscular sarcocystosis follows ingestion of food or water contaminated with zoonotic Sarcocystis spp. sporocysts, as evidenced by infection outbreaks by Sarcocystis nesbitti among travelers returning from exotic destinations in Malaysia. Further, Sarcocystis fayeri, which cycles between horses and dogs, has been implicated in cases of food poisoning in humans following consumption of raw horse meat. Clinical features range from asymptomatic cases to acute symptoms, such as muscle pain, fever, and, in severe cases, neurological complications. Diagnosis relies on clinical presentation supported by microscopy, histopathology, serology, and advanced molecular techniques. Therapeutic options are limited; antiprotozoal agents including sulfadiazine, pyrimethamine, decoquinate, clindamycin, and triazine derivatives have shown high efficacies. Preventive measures focus on hygienic meat handling, thorough cooking, and restricting carrion scavenging by stray carnivores. Increasing human-wildlife interactions elevate the risk of cross-species transmission of novel Sarcocystis species. Adopting a One Health approach is fundamental for understanding the epidemiology and transmission dynamics of zoonotic sarcocystosis and reducing future outbreaks through effective diagnostics, therapeutics, and preventive interventions.