Hey there, time traveller!
This article was published 11/4/2013 (1501 days ago), so information in it may no longer be current.
2 I know, when travelling in the less-hygienic part of the world, having an icy drink may result in the "Hong Kong trots" or "Montezuma's revenge," or on an especially unlucky day, even a hepatitis B infection. Even in some North American locations, I sometimes decline ice. Why? Because I never want to see Ascaris lumbricoides in the toilet bowl. If it ever happens to you, it's a sight you will never forget.
During my time as a family doctor, a family arrived with their young, frightened son. After a bowel movement, he had noticed what he described as a "garden worm" in the toilet, and he had fished it out. Identification proved it to be Ascaris lumbricoides.
How had the boy contracted this worm? Millions of dogs, cats and other animals are now sharing close quarters with North American families. At times, this results in serious injury when an animal mangles a child, but other problems are less obvious and young children are particularly vulnerable.
Dogs and cats often defecate in playground areas. One study of 229 family dogs showed 189 had roundworm, hookworm, tapeworm or other parasites. Children who swallow a parasite egg can later pass a worm as long as 30.5 centimetres. Can this also happen to adults? You bet, and it can make their hair stand on end.
Roundworms are very fertile, laying up to 100,000 eggs a day. If one of these eggs is accidentally ingested by a dog, the worm hatches and makes its way to the intestines, an ideal feeding ground, to be passed on later to humans.
Ascaris lumbricoides can also trigger human intestinal symptoms. A 65-year-old man was admitted to emergency complaining of vomiting and severe pain suggestive of intestinal obstruction. X-rays confirmed the diagnosis. But just before surgery, the man suddenly expelled a huge lump of worms. His symptoms quickly subsided.
I'm sure many readers are thinking this problem is rare. After all, we don't live in the tropics. But according to the U.S. Centers for Disease Control, a quarter of the world's population suffers from Ascaris lumbricoides and four million North Americans harbour this worm.
During a visit to the London School of Hygiene and Tropical Medicine, I discovered worms can cause more than intestinal obstruction. One of the school's doctors had a hair-raising experience. He was performing a routine eye examination when suddenly he observed an exotic worm from West Africa crossing the patient's eyeball. On rare occasions, Ascaris lumbricoides can also infect the eye.
I love dogs, but I've often watched friends run their hands down their beloved Fido's tail, then reach for the ice cubes! Worms such as Ascaris are picked up from fecal contamination, and I've never seen Fido washing his tail after defecating. This is when I say "no" to ice cubes in my drink.
But Fido isn't the only animal that can cause problems.
Pregnant women must be careful of cats, as their feces can cause toxoplasmosis. During pregnancy, this parasite can be transmitted to the fetus, resulting in serious birth defects. So when pregnant, let someone else clean out the litter box.
Remember that pet squirrels have a tendency to bite. Turtles can pass along salmonella infection to the entire family, causing severe diarrhea, so it's not prudent to dump turtle water into the kitchen sink. Parrots, parakeets and pigeons are noted for causing a lung infection called psittacosis. Monkeys are dangerous pets. If you are crazy enough to keep one in the house, you may end up with hepatitis, measles, encephalitis or amebic dysentery.
Suppose your child can't live without owning a hamster. These animals can cause lymphocytic choriomeningitis, so make sure you buy it from a colony that has been screened for this virus.
It's been said that cleanliness is next to godliness, and who can argue with this advice? But it can also save you from having your hair stand on end.
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