SUMMARY

The incidence of cryptosporidiosis in our unit has increased over the last 6 years, being diagnosed in approximately 5 per cent of all patients with HIV infection and in 21 per cent of those with AIDS, but a marked seasonal variation occurs. We have studied the course of the infection in 128 patients and identified four clinical patterns of disease: transient (28.7 per cent), chronic (59.7 per cent), fulminant (7.8 per cent) and asymptomatic (3.9 per cent). Transient disease occurred in patients with a wide range of CD4 lymphocyte counts, but was more common in less immunosuppressed patients. Fulminant disease, defined by the passage of more than 2 I of stool/day from the time of presentation, only occurred in patients with a CD4 count less than 50/mm3. This group had lost more than 7 kg in weight at presentation and more commonly had other intercurrent gastrointestinal infections. They survived for a median of only 5 weeks, compared with 20 weeks for those with chronic diarrhoea and 36 weeks for those with transient infection. The survival was unaffected by any treatment other than zidovudine. Cryptosporidiosis in HIV-infected individuals is a heterogeneous disease