Abstract
Cryptosporidium parvum is one of the leading causes of opportunistic infections among HIV/AIDS
patients. Due to the small size of its oocysts, detection of this protozoan requires special staining and
laboratory expertise. In this study, we compare the effectiveness of the three leading parasitology laboratories
in Mahidol University, Thailand. Serial concentrations of Cryptosporidium parvum oocysts from 6 to
1,500 oocysts per 10 μl were added to stool samples and distributed to the study laboratories. Conventional
microscopy and special staining, using dimethyl sulfoxide (DMSO) modified acid-fast stain and
modified cold Kinyoun’s acid-fast techniques were applied. The sensitivity of both techniques was similar.
All three laboratories could detect at least as many as 20 oocysts per 10μl with no statistically significant
difference (p= 0.998). Either staining method could be applied at any laboratories serving HIV patients
with opportunistic infections. However, training laboratory technicians to acquire such expertise
and standardize it is necessary. Effective laboratory diagnosis would be very helpful for physicians, leading
to patients’ appropriate management.
