Porcine taeniasis is an intestinal tapeworm disease caused by the adult Taenia solium tapeworm parasitizing the human small intestine. Ancient Chinese medical books referred to it as 'Chai worm' or 'Bai worm', and it was already known that eating raw meat was the cause of tapeworm disease. It is the main tapeworm that parasitizes humans in China.
Porcine taeniasis is widely distributed worldwide. In Europe, there are many countries where the Slavic people in the southern part of Europe are predominant, such as the former Yugoslavia, Czechoslovakia, the former Soviet Union, and Germany, where the disease also occurs. In Latin America, the disease is prevalent in countries such as Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panama, and Brazil. In Mexico, 4.34% of the 128,025 pigs had 'mutton pork'. In Africa, tapeworm infection is also widespread in Nigeria, and the disease occurs and spreads in Egypt. There are scattered cases in Australia, and the disease occurs and spreads in India, North Korea, China, and other Asian countries.
The distribution range of porcine taeniasis and cysticercosis in China includes 25 provinces, municipalities, and autonomous regions such as Jilin, Liaoning, Heilongjiang, Beijing, Tianjin, Shanxi, Hebei, Inner Mongolia, Yunnan, Sichuan, Guizhou, Tibet, Gansu, Qinghai, Shaanxi, Xinjiang, Anhui, Fujian, Shandong, Shanghai, Jiangsu, Hunan, Hubei, Henan, Guangxi. Among them, the three northeastern provinces, Inner Mongolia, Henan, Shandong, Hebei, and the southwestern region are high-risk areas. Fujian and Shanxi provinces are also relatively common, and some areas in Yunnan Province have localized endemic outbreaks, such as the Bai ethnic group in Dali, Yunnan, who have the habit of eating raw pork (eating the skin), with an infection rate as high as 19.52% [2]. Moreover, the infection shows a clear family clustering.
The prevalence of this disease is mainly related to the ways pigs are raised and the living habits of residents. Due to residents defecating at will, simple toilets, or pig pens being connected to human toilets, pigs can eat the feces of patients and become infected; the free-range farming of pigs increases their chances of infection. Human infection is directly related to the dietary habits of residents. Residents in Yunnan and Guizhou provinces have the habit of eating raw pork, such as cutting the meat into slices after burning the hair with fire and dipping it in sauce to eat, thus leading to a higher infection rate. In most parts of China, residents often become infected due to eating large pieces of meat that are not fully cooked, or food with meat filling that is not cooked for a sufficient time, or when the temperature is not evenly applied while stir-frying slices of meat, leading to the incomplete killing of the cysticercus in the meat. Therefore, controlling the temperature and cooking time is very important for preventing infection. Using a knife or cutting board that has been used for raw meat to cut cooked food can also lead to infection due to contamination of the cysticercus.
