Madam, Cryptosporidium, a protozoan parasite has recently been identified as a causative agent of diarrhoea in India¹, Bangladesh², Sri Lanka³ and Pakistan⁴. In order to determine the frequency of diarrhoea due to this protozoan in our patients, we collected 550 faecal samples betweenJanuary 1989 toJuly 1991 from different hospitals in Karachi. A modified Kinyoun acid fast stain was used to stain the parasite. Faecai smears were air dried and fixed in methanol for 3 minutes, stained with basic fuchsin for 2 minutes⁵, washed with tap water, decolorized with 1% sulphuric acid for 1 minute and counter stained with 0.5% malachite green for 30 seconds. On examiantion under high power and oil immersion the cryptosporidlum oocyst stained bright red agaist a green background. Of 550 faecal samples examined, 190 (35.6%) were positive for cryptosporidium. The number of oocyst per high power field was high (> 10) in majority of the cases indicating that this protozoal infestation is an important cause of diarrhoea in our country. It is possible that a large number of cases are not detected as the symptoms of cryptosporidiosis are similar to any other gastrointes­tinal infections and faecal samples are not routinely screened for this parasite. Lack of experience, inadequate preparation of slide or improper staining further con­tribute to the low yield. As the number of cases reported is high further clinical study is being conducted and the effect of spiramycin/rovithromycin in the treatment of cryp­tosporidiosis is being investigated.

The authors are grateful to Dr. Javed Kazi, Pathologist, Liaquat National Hospital for his help in collection of faecal samples from diarrhoeal patients.

Rakhshanda Baqai, Saleem Hafiz and Sarwar J. Zuberi
PMRC Researcb Centre, Jinnah Postgraduate Medical Centre, Karachi.

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