A medical mystery reveals a new host for the rat lungworm parasite
This disease can be spread by eating centipedes, frogs, snails and other creatures
When a 78-year-old woman went to a hospital in Guangzhou, China, in November 2012 complaining of a headache, drowsiness and a stiff neck, doctors initially were puzzled. The patient had meningitis, but no signs of bacteria or viruses that can cause the illness. Then a cerebrospinal fluid test revealed she had a high number of white blood cells called eosinophils, a clue that she was fighting a parasitic infection. That helped the doctors zero in on a culprit: a thin, swirly-patterned worm called Angiostrongylus cantonensis. The woman was suffering from rat lungworm disease. So was her adult son.
But how were the pair infected? Rat lungworm disease, which gets its name from the fact that the worm eggs hatch in the lungs of rats, is commonly associated with ingesting snails or slugs (SN Online: 7/21/16). Infected rats poop out the worm larvae, which the mollusks can then pick up and pass on to humans if eaten. Yet the patients had eaten no slugs or snails.
An investigation of the pair’s diet revealed they had eaten Chinese red-headed centipedes bought at the market. “Centipede is a common traditional Chinese medicine,” usually consumed in a dried powder, says Lingli Lu, a neurologist at Zhujiang Hospital in Guangzhou. The two patients, however, had eaten them raw.
Lu and her colleagues confirmed the source of the infection by testing 20 centipedes they bought from the same market. The team discovered A. cantonensis larvae that could infect humans in seven of the centipedes. The infected worms had an average of 56 larvae each. The case is the first evidence that eating raw centipedes contaminated with worm larvae can transmit rat lungworm disease, the researchers report July 30 in the American Journal of Tropical Medicine and Hygiene.