A 29 year old man in Sydney, Australia has died on Friday, eight years after he contracted a parasite from eating a slug on a dare during a party in 2010. The incident initially left him paralyzed after waking from coma for 420 days. The odd and tragic death of Sam Ballard has highlighted the seriousness of a rare parasite called rat lungworm.
Ballard’s friend said that they were all sitting together having some red wine when a slug came crawling across towards them. Sam asked if he should eat it, and then put the slug in his mouth and swallowed. Days later, Ballard complained of pain in his leg, and was eventually diagnosed with a rat lungworm disease by a doctor.
The parasite is called Angiostrongylus cantonensis and it is harbored by rats and also passed to snails and slugs, which can further spread the worm to humans. Once ingested, the worm can pierce through the intestine, travel across the nervous system, and reside into the brain’s superficial surface.
According to Centers for Disease Control and Prevention (CDC), most people will recuperate from the infection, but it can also leave a rare version of meningitis, and may cause headache, stiff neck or painful sensation in the skin, nausea, fever and vomiting.
Ballard was diagnosed with the same rare version of meningitis, which initially put him in a coma for 60 weeks. When he regained consciousness, Ballard was left with significant brain damage, and was unable to move his limbs. He became quadriplegic, had seizures, and so required permanent care.
Ballard’s unfortunate case has generated a newfound awareness about the tiny parasite. Rat lungworm has spread across 30 countries including US, with at least 2,800 cases of the disease reported so far. It even caused some fears in Hawaii last year when a few dozen cases emerged across the state.
Transmission of the parasite occurs when a rat swallows down worm’s larvae into its stomach. The larvae then pass through the digestive system, and get released through rat’s excrement. Slugs or snails become intermediate hosts by consuming the rat’s excrement and subsequently contracting the parasite.
When one of these infected gastropods is eaten by rats, the worm’s life cycle is reset. The larvae grow into adults within the rat’s brain, before traversing to the lungs via the pulmonary arteries and finally burrowing and reproducing there.
Humans and other animals can become affected in case they consume an infected slug or snail. Accidental infection can happen due to unwashed produce containing an infected slug or snail, including slime, as according to health officials. Less commonly, contaminated drinking water can also transmit the infection.
“The parasites are moving around in the lining of my brain,” said a Hawaii woman who got infected with rat lungworm. “My visual graphic for what’s happening is that every once in a while the top of my head is opened up, with a hot iron put inside my brain, and then the steam button is pressed.”
Doctors usually perform a spinal tap to diagnose the infection. There is no rat lungworm test currently available, and endeavors to develop a test for antibodies linked to the infection have not proven much useful either. The CDC has given guidelines in order to prevent the spread of infection.
Thankfully, the infection only lasts 1 to 2 weeks, with an incubation time of 1 to 3 weeks. There is no standard medical cure, though steroids, painkiller and antibiotics are mostly prescribed to control the symptoms. According to the CDC, the disease is not contagious. And most worms usually die without treatment, although the dying parasites can cause a painful immune reaction.