From DoctorMyhill
Jump to: navigation, search


It is estimated that 2-3% of the British population may be infected with toxocara (dog and cat roundworm) of which 100 cases of eye disease largely in children arise. Puppies and the pregnant bitch are the main source because the eggs appear in their faeces (however, they take two weeks to become infectious, so fresh faeces are not too bad!). These can be picked up by children playing on contaminated ground. All cats and dogs (especially puppies and kittens) must be regularly wormed.

Symptoms of roundworm infection in humans are:

  • Nothing at all, just worms in the stool.
  • Sight loss due to inflammation in the optic nerve, retinal fibrosis and possibly detachment, squint, eye pain, red eye. 97% just have symptoms in one eye.
  • Visceral larva migrans: as the worms migrate through the gut they cause fever, malaise, cough, pain, wheeze and possibly failure to thrive. The child, usually under 5, usually gets better without being diagnosed.
  • Overt toxicara: childhood fever, cough, disturbed sleep, abdominal pain, head ache, behavioural disturbance, swollen liver, swollen glands and wheezing.

Diagnosis is made by seeing worms in the stool (they are a pale round bodied worm up to 6 inches in length) or doing blood tests for antibodies to toxocara at the Scottish Parasite Diagnostic Laboratory, House on the Hill, Stobhill Hospital, Glasgow, G21 3UW. Tel: 0141 201 8667 or see Scottish Parasite Diagnostic Laboratory.

Ideally a stool sample should be sent to the London School of Hygiene and Tropical Medicine - see London School of Hygiene and Tropical Medicine - we can send you a kit for this test.

Treating roundworm

Treatment is with mebendazole (Vermox) 100mgs twice daily for three days.

Please note, Vermox should not be used during pregnancy

Thread worms

Thread worms are very common and cause no serious illness. They tend to crawl out of the anus in the evenings and at night (how do they know when it's night-time? I've often wondered! Maybe it's simply when we cease to be active, and they would come out in the day if we slept then.) to lay their eggs before they die. This usually causes itching, which is wonderful for the worm because the child scratches, gets the eggs stuck on the fingers and under the finger nails and promptly re-infects itself next time the fingers goes into his mouth, or even better for the worm, somebody else's mouth! The adult worm lives about 6 weeks.

Ideally the diagnosis should be made by seeing the worms, usually on the child's bottom, just round the anus. They are called thread worms because they look like pieces of white cotton thread about a centimetre long, often wriggling. Some people don't bother to treat because these worms are harmless. If the child never scratched their bum and kept their hands scrupulously clean, eventually the worms would die out. And pigs might fly.

There is a theory, growing in popularity, that worms are protective against the development of allergy. Type I allergy is mediated by white blood cell called eosinophils and mast cells. The normal function of these two cells is to fight and get rid of worms. It may well be that if there are not any worms about, these cells turn their attention to things which they should really ignore such as house dust mite, animal dander or foods. In Africa, people with type I allergy are relatively protected against worms and this has positive survival value. In Western societies, where worms have largely been eliminated through good hygiene, type I allergy is a nuisance.

I usually prescribe mebendazole (Vermox) 100mg one dose, repeated one week later. It can be bought over the counter from chemists. The whole family should be dosed.

Please note, Vermox should not be used during pregnancy


These are acquired in the same way as round worms and are seen in the stool. These worms have bodies which are flatter and clearly segmented. They break off in the gut in bits and often several sections can be seen moving in the stool (sorry, I suddenly feel a bit sick!).

Treating Tapeworms

Once diagnosed, treatment is with Niclosamide (Yomesan), which is only available on a named patient basis.

Rarely hydatid cysts develop in the liver or brain (possible cause of epilepsy) and treatment is surgical.

Again blood and stool specimens should be taken and I can send you a kit for these tests.

External Links

Sarah Myhill Limited  :: Registered in England and Wales  :: Registration No. 4545198
Registered Office: Upper Weston, Llangunllo, Knighton, Powys, Wales LD7 1SL, UK. Tel 01547 550331 | Fax 01547 550339