title: Prevalences of Giardia lamblia and Cryptosporidium parvum infection in adults presenting with chronic diarrhoea.
abstract: Giardia lamblia and Cryptosporidium parvum are both waterborne pathogens associated with diarrhoea in developing countries. In a recent study based at the Aga Khan University in Karachi, 334 adults aged 16-83 years (178 patients with chronic diarrhoea and 156 diarrhoea-free volunteers who acted as controls) were checked for infection with these parasites, using stool microscopy and/or PCR. Overall, 21 (6.3%) and 29 (8.7%) of the subjects were found positive for G. lamblia by microscopy and PCR, respectively, while the corresponding values for C. parvum were 13 (3.9%) and 14 (4.2%). Although, compared with the diarrhoea-free controls, the patients with diarrhoea were not significantly more likely to be found infected with Giardia, either by microscopy [15 (8.4%) v. six (3.8%); P=0.085] or PCR [19 (10.7%) v. 10 (6.4%); P=0.167], they were significantly more likely to be found infected with C. parvum, both by microscopy [11 (6.2%) v. two (1.3%); P=0.024] and by PCR [12 (6.7%) v. two (1.3%); P=0.014]. The 19 patients found PCR-positive for Giardia comprised 10 (67%) of the 15 found smear-positive for the same parasite but only nine (5%) of the 163 found smear-negative (k=0.545; P<0.001). Similarly, the 12 patients found PCR-positive for Cryptosporidium comprised all 11 (100%) patients found smear-positive for the same parasite but only one (0.6%) of the 167 found smear-negative (k=0.954; P<0.001). Although C. parvum was associated with chronic diarrhoea in the present study, the carriage of G. lamblia often appeared asymptomatic.
authors.affiliation: Department of Medicine, Aga Khan University, Karachi B, Pakistan. yakoobjaved@hotmail.com
authors.forename: J
authors.initials: J
authors.lastname: Yakoob
authors.forename: Z
authors.initials: Z
authors.lastname: Abbas
authors.forename: M A
authors.initials: MA
authors.lastname: Beg
authors.forename: S
authors.initials: S
authors.lastname: Naz
authors.forename: R
authors.initials: R
authors.lastname: Khan
authors.forename: M
authors.initials: M
authors.lastname: Islam
authors.forename: W
authors.initials: W
authors.lastname: Jafri
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease; D003457:Cryptosporidiosis / Q000150:complications / Q000453:epidemiology* / Q000469:parasitology; D016785:Cryptosporidium parvum / Q000302:isolation & purification; D003967:Diarrhea / Q000469:parasitology*; D005243:Feces / Q000469:parasitology; D005260:Female; D016829:Giardia lamblia / Q000302:isolation & purification; D005873:Giardiasis / Q000150:complications / Q000453:epidemiology* / Q000469:parasitology; D006801:Humans; D008297:Male; D008853:Microscopy; D008875:Middle Aged; D010154:Pakistan / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D015995:Prevalence; D055815:Young Adult