Medical mystery reveals a new host of parasitic roundworms on mice

This disease can be spread by eating centipedes, frogs, snails and other organisms.

When a 78-year-old woman was hospitalized in Guangzhou, China in November 2012 complained of a headache, stiffness and stiff neck, doctors were initially confused. Patients with meningitis, but there are no signs of bacteria or viruses that can cause this disease.

Chinese centipede.

Then a cerebrospinal fluid test showed that she had a high number of white blood cells called eosinophils , a proof that she was fighting a parasitic infection . That helps doctors focus on one culprit: a long, often twisted worm called Angiostrongylus cantonensis . The woman has contracted parasitic nematode in mice. So is her adult son.

But why are these two people infected?The parasitic nematode worm on the mouse , whose name is derived from the fact that the strongyloid eggs are hatched in the rat lungs, often accompany eating snails or slugs. Rats infected with parasites release worm larvae, then molluscs can be ingested and transmitted to humans if eaten by humans. But the two patients did not eat slugs or snails.

An investigation of the diets of these two people showed that they ate the red-headed Chinese food bought at the market. Lingli Lu, a neurosurgeon at Chau Giang Hospital in Guangzhou, said: 'Centipede is a popular Chinese traditional medicine' , often used in dry powder form. However, two patients have eaten them alive.

Angiostrongylus cantonensis larvae - (Photo from H. Wanget al / Am. J. Trop. Med. Hyg.2018).

Lu and his colleagues confirmed the source of the parasite infection by examining 20 centipedes they bought from the market. The team discovered that A. cantonensis larvae could infect humans in seven centipedes. Each parasite infected with parasites has an average of 56 larvae. According to a report by researchers in the American Journal of Tropical Medicine and Hygiene on July 30, this is the first evidence that living centipedes infected with worm larvae can transmit parasitic nematode worms.

This finding has added to the growing list of hosts that can transmit this parasite to humans. While strongyloid worms need snails to complete their life cycle, other animals, called intermediate hosts (not needed for the parasite's growth cycle), can eat snails and then transmission of disease to humans.

People infected nematode parasites in rats due to eating freshwater shrimp, frog, crab and iguanas. Once inside a human body, strongyloidiasis will move to the brain, where they will eventually die. While symptoms may be mild, parasite infection can cause damage to the central nervous system, including cerebral edema, polio and even death. People infected with parasites cannot spread the disease to others.

According to Heather Stockdale Walden, a parasite researcher from the University of Florida Veterinary Institute, Gainesvill, rat parasitic nematode is still considered rare (there are about 3,000 cases recorded in the world), and the disease This is most common in tropical and subtropical regions. In the United States, these parasites are specific to Island of Hawaii, and cases of rat parasitic nematode infections have been reported in both Oklahoma.

Most cases in the United States stem from eating snails and snails in unwashed agricultural products. According to Walden, people should recognize this parasite, but don't be afraid.'As long as you cook food and wash food, the chance of getting parasites is quite low . '