Prevalence of Cryptosporidium-associated diarrhea in a high altitude-community of Saudi Arabia detected by conventional and molecular methods

Abstract

Cryptosporidium diarrhea represents a relevant clinical problem in developing countries. In Al-Taif, a city of Saudi Arabia that lies at an altitude of an around 2 km above the sea level, Cryptosporidium infection seems to be undiagnosed in nearly all clinical laboratories. Furthermore, nothing was published regarding Cryptosporidium-associated diarrhea in this area. The objectives of this research were to (1) determine the Cryptosporidium prevalence among patients with diarrhea and (2) to estimate the performances of 3 different diagnostic methods. Total 180 diarrheal fecal samples, 1 sample per patient, were collected between January and August 2013. Samples were screened for Cryptosporidium with modified Zeihl Neelsen (ZN) microscopy, RIDA® Quick lateral flow (LF) immunotest, and a previously published PCR. The Cryptosporidium prevalence rate was 9.4% (17/180), 10% (18/180), and 11.6% (21/180) by microscopy, LF, and PCR test, respectively. Infection was significantly (P=0.004) predominant among children <5 years (22%) followed by children 5-9 years (11.1%). Although infection was higher in males than in females (16.2% males and 8.5% females), the difference was not statistically significant (P=0.11). Compared to PCR, the sensitivity of microscopy and the LF test were 80.9%, 85.7%, respectively. To conclude, high Cryptosporidium-associated diarrhea was found in this area especially in children ≤9 years. The PCR test showed the best performance followed by the LF test and ZN staining microscopy. The primary health care providers in Al-Taif need to be aware of and do testing for this protozoon, particularly for children seen with diarrhea.

Keywords: Cryptosporidium; PCR; diarrhea; high altitude; lateral flow test; microscopy.

Fig. 1

Microscopic picture of Cryptosporidium oocysts (red) in a wet mount smear prepared from a fecal specimen concentrated by modified formol-ether method and stained following the modified Zeihl Neelsen procedure (×400 magnification).

Fig. 2

Representative ethidium bromide-stained 1% agarose gel electrophoresis picture showing the PCR test results of 12 samples (Lane 1-12) diagnosed as Cryptosporidium-negative by the LF test. M: GeneRuler™ 100 bp DNA marker; Lanes 1, 3, and 12: PCR products, ≈550 bp each, recovered from Cryptosporidium DNA-positive samples. Lane 2, 4-11: Cryptosporidium DNA-negative samples. Lane 13: PCR-negative control (master mix without template DNA).

Fig. 3

Age-distribution of 4 patients diagnosed as Cryptosporidium-negative by microscopy and proved to be positive by the PCR assay.