A study has, for the first time, found high levels of tapeworm infection can potentially cause cognitive defects among primary schoolchildren in rural mountainous areas.
Researchers in a joint study by Stanford University in the United States and Sichuan province's health authority stated that such infections have made the children highly susceptible to disease, with severe social consequences.
According to the research, the neurological problems caused by the infections could lead to poor academic performance, dropping out of school and reinforcement of the poverty cycle.
"This disease invades the brain," said John Openshaw of Stanford School of Medicine and the study's lead author. "Children who are affected during formative school years' risk cognitive deficits which could enforce a cycle of poverty."
On the other hand, the study, co-authored with researchers at Sichuan Centre for Disease Control and Prevention, calculated about 3,000 children in 27 schools for the tapeworm infection, by questionnaire and by analyzing their blood samples in 2015. The children, with an age range from 11 to 13, were drawn from three counties at high altitude in western Sichuan province.
Their findings were published in international scientific journal PLOS Neglected Tropical Diseases last week.
The study focused on one type of tapeworm, taenia solium, whose eggs can be transmitted to humans by contaminated food, such as improperly cooked pork, water and close contact with a carrier.
The lava infects human intestines and releases thousands of eggs that pass through human faeces and are consumed by pigs, directly or through contaminated agricultural products.
Mature eggs, once hatched in the human body, migrate to tissues through the body, including muscles and the central nervous system, causing seizure, loss of vision and hallucination.
The World Health Organisation estimates that the infection is one of the leading causes of epilepsy in the developing world and results in 29 per cent of epilepsy cases in endemic areas.
Although there have been epidemiological studies suggesting a high prevalence of tapeworm infection in rural China, the prevalence in children and its risk factors were unknown.
Researchers found that among the overall population prevalence of tapeworm infection was 6 per cent, but in some schools the rate rose to 15 per cent or higher.
The average prevalence of taenia solium infection in China was found to be 0.11 per cent. The estimated number of patients with taeniasis was 1.26 million, and the estimated number of cysticercosis cases was 3 million, according to the China Centre for Disease Control and Prevention.
Tapeworm infection occurs when the child ingests the egg or larvae of a tapeworm.
There are at least three types of tapeworms that can be ingested by children.
Some are found in beef, fish and pork. The larvae of beef and fish tapeworms are often directly ingested by eating undercooked, contaminated meat. This differs from pork tapeworm eggs, which are spread through food and water sources that have been contaminated with the feces of infected pigs.
On the other hand, the ingested beef and fish tapeworm larvae attach inside the intestine, where they feed and grow. In contrast, pork tapeworm eggs grow into larvae inside the intestines and then migrate to other tissues in the body, where they form cysts.
