During September 2007–October 2009, fecal specimens were collected from children in hospitals I (3,245 patients), II (489), and III (2,550), in Shanghai, People’s Republic of China. The children (1 month–19 years old, median 36 months) were hospitalized primarily for nongastrointestinal illnesses. For each patient, information was collected on age; sex; occurrence of diarrhea; and, later in the study, ward assignment in hospital I. The study was approved by the ethics committee of East China University of Science and Technology, Shanghai.
spp. were detected in the specimens and differentiated by PCR and restriction fragment length polymorphism analysis of the small subunit rRNA gene (11
). C. hominis
was subtyped by sequence analysis of the 60-kDa glycoprotein gene (12
). Each specimen was analyzed at least 2× by PCR, with positive and negative controls in each run. Prevalence rates and 95% CIs were computed; the χ2
test was used to test differences. Odds ratios (ORs) and 95% CIs were calculated.
Among the 6,284 patients, 102 were positive for Cryptosporidium spp.: 90 from hospital I (2.8%, 95% CI 2.2–3.3), 3 from hospital II (0.6%, 95% CI 0–1.3), and 9 from hospital III (0.4%, 95% CI 0.1–0.6) (p<0.01). Ward assignment was available for 1,592 of 3,245 patients in hospital I. In most of the 12 wards, the infection rate was 0%–2.3%; in ward A, it was 51.4% (p<0.01) ().
Distribution of Cryptosporidium spp. and subtypes among wards in a hospital in Shanghai, People’s Republic of China, September 2007–October 2009*
In hospital I, children <6 months old had a significantly higher positive rate (8.4%, 95% CI 5.6–11.2) than older children (1.9%, 95% CI 1.4–2.4) (p<0.01; data not shown). This was mainly because of a high infection rate among the age group in ward A (61.5%, 95% CI 36.9–86.2) versus those in other wards (40.0%, 95% CI 19.0–61.0). No age-associated difference in infection rates was found in other wards (p = 0.80; data not shown).
Cryptosporidiosis was more prevalent during February–July 2008 (p<0.01). Prevalence rates remained at ≈6% in the monthly distribution of the 2 main C. hominis subtypes in hospital I; however, when adequate numbers of patients were sampled, rates of Cryptosporidium infection in ward A remained >28% in most study months.
C. hominis was identified in 90.2% (92/102) of Cryptosporidium-positive patients in the 3 hospitals, of whom 86 were patients in hospital I. In hospital I, C. hominis was detected only in ward A; C. meleagridis was isolated from 4 patients in other wards (). In contrast, C. canis (1 case) and C. hominis (2 cases) were identified in hospital II patients, and C. canis (1 case), C. hominis (4 cases), C. felis (2 cases), and C. meleagridis (2 cases) were identified in hospital III patients ().
Six C. hominis subtypes were found at the 3 hospitals; 4 were in 73 specimens from hospital I (). Of those 73 specimens, 71 (97.3%) were subtype IaA14R4 or IdA19, and they were mostly found in ward A and unknown wards (). Other subtypes (IbA19G2 and IdA14) were not found in ward A (). With 1 exception, subtypes in hospital I were not found in other hospitals; subtype IaA14R4 was found in 2 patients in hospital III. Likewise, subtypes IaA18R4 (in 1 patient in hospital II) and IgA14 (in 1 patient in hospital III) were not found in hospital I.
In hospital I, 44 of 1,084 patients with diarrhea (4.1%, 95% CI 2.9–5.3) and 46 of 2,161 without diarrhea (2.1%, 95% CI 1.5–2.7) were positive for Cryptosporidium spp. (p = 0.002, OR 1.95, 95% CI 1.28–2.96). C. hominis subtype IaA14R4 (21 diarrheic and 13 nondiarrheic cases) was significantly associated with diarrhea (p = 0.0004, OR 3.29, 95% CI 1.64–6.59), but subtype IdA19 (11 diarrheic and 26 nondiarrheic cases) was not (OR 0.86, 95% CI 0.42–1.75, p = 0.68).