Many patients who are treated as amoebiasis are actually suffering from giardia and respond to so called ''treatment'' This is because the drugs used are same and the dose and duration of drugs for giardia is much less. For example the dose of tinidazole in a strip of four tablets of Fasigyn is enough to get relief from giardiasis, while the same dose continued for three days is effective for amoebiasis.

The following discussion will be self explanatory.

Few years back 'giardia lamblia was discovered by Van Leeuwenhoek in his own stool, with his own miscroscope. Since then infestation has been recognised all around the world. But in many developing countries giardiasis is so common that most if not all village children become infected during early childhood (this often permits an efficient immunity to develop, which is lacking in many adults living in aristocratic societies in the big cities). Unlike amoebiasis the mode of infection in giardiasis is not always faeco-oral route.

It can really be compared to the life cycle of the thread worm, which is of the nature of an auto infection. More the reason, that like in the case of thread worms, the whole family should

be treated at the same time. Unfortunately, the ideal drug for giardiasis is Mepacrine. This is not available and is slightly toxic to be used by the present day standards (It was used routinely for years in the treatment of malaria) The parasite sets up colonies in the duodenum and upper small intestines, and with the poor sanitation (with the faeco-oral route even with good sanitation), the infection persists .

Giardiasis is more notorious than amoebiasis to lead to decreased levels of disaccharides such as maltose, sucrose and lactose. This causes symptoms of milk intolerance and foul flatus.

Finally a word about the diagnosis of giardiasis. Presence of trophozoite form or cystic forms of giardia in the stools (former easy to find in freshly passed diarrhoeal stool) is diagnostic. Unfortunately stool examination is often negative. Like in amebiasis it is necessary to examine several stool samples over a few days to detect the cysts, which is difficult in private practice.

The other investigations are costly, and invasive. For example duodenal intubation to detect the parasites or peroral jejunal biopsy lead to a more accurate diagnosis.

In practice we can only look forward to days when serological tests for the serum antibodies will be available. But that will not solve all the problems because the diagnostic titres will have to be established in immune persons. Or if the early reports of antigen detection in giardiasis come true, the diagnosis will certainly be facilitated.

Further Reading

1. Giardiasis, ‘British Medical Journal’, 18^th May 1974, Page 347.
2. Battles Against Giardia in Gut Mucosa, The Lancet, September 4^th, 1982, Page 527.
3. Rapid Reinfection by Giardia Lamblia After Treatment in a Hyperendemic Third World Community. Robert H. Gilman, Elba Miranda, Grace S. Marquis, Manuela Vestegui, Homero Martinez. The Lancet, February 13^th, 1988, Page 343.
4. Diagnosis of Giardia Lamblia Infection as a Cause of Diarrhoea. E.J. Eastham, Adrian P. Douglas, A.J. Watson, The Lancet, October 30^th, 1976, Page 950.
5. Epidemic Giardiasis, The Lancet, December 21^st, 1974, Page 1493.
6. Oxford Textbook of Medicine, Second Edition, Volume 1, Edited by D.J. Weatherall, J.G.G. Ledingham and D.A. Warrell, Page 5-512.