Sarcocystosis is a protozoan infection caused by unicellular organisms belonging to the Sarcocystis genus. These organisms infect the soft tissues such as the muscles of their hosts. Cats and dogs are their final hosts, but they spend part of their life cycles in intermediate hosts. Besides reptiles and rodents, domestic animals such as pigs and cattle play the role of intermediate hosts in whom these organisms makes cysts. People can also be infected.
The cysts are of different sizes depending on the various species of this organism. The larger Sarcocystis cysts can be seen with our naked eyes, but some are microscopic in size.
Transmission to the dogs is mainly through ingesting raw or undercooked pork or beef which introduces the viable sporocysts into them. Food contaminated by the feces of an animal that carries the sporocysts can also cause the infection in the dogs. Mild diarrhea is the usual symptom of sarcocystosis, but most of the dogs carrying the infection may not display any symptoms.
When humans play host to these protozoans, they may have muscle soreness and inflammation of the blood vessels. It is not clear how the infection is transmitted to humans, but when it happens, they may abdominal pain accompanied by nausea and diarrhea for about 2 days. Since human infections are rare, its source and effects are not clear, but consumption of infected meat is held as the channel of transmission.
The cysts are present in the muscle tissue of almost all pigs, sheep and cattle; hence dogs should be prevented from eating the carcasses of dead animals found in the wild. They should not be given uncooked meat or organs of the above-mentioned animals. Grain and feed stocks should be kept covered to prevent rodents accessing them. Dogs must be kept away from buildings housing other domestic animals and where their feed is stored.
No vaccines are there to prevent sarcocystosis. Pork cooked at 1580F or 700C for more than 15 minutes can be eaten. Freezing can also destroy the cysts, but the meat should be frozen for minimum one entire day at 40F (-200C) or two days at 250F (-40C) to make it safe.