Introduction

Cryptosporidium is a leading cause of persistent diarrhoea in developing countries. With proper oral hydration therapy, full recovery from this coccidian is expected in immunocompetent individuals¹. In one study in West Africa, C. parvum was identified to be the most significant pathogen in infections characterized by acute and persistent diarrhea². Cryptosporidiosis is widespread and affects all ages,^3,4,5 and documented evidence indicated the parasite as a cause of diarrhoea in 95 countries^6,7. Cryptosporidium is recognized as a significant and widespread cause of diarrheal illness in both immunocompetent and immunosuppressed hosts⁸. Cryptosporidium may cause severe symptoms in persons with weak immune systems⁹.

The Cryptosporidium species was described as a minute coccidian parasite of the gastric crypts of a laboratory mouse. The first case of human infection was reported in 1978 in a Japanese boy.^10,11

The oocysts survive considerable periods in cool, moist environment and resist common disinfections including chlorine, even in excess of those used in water treatment¹². Person -to- person transmission is now recognized to be common by faecal-oral route, directly or through formites¹². Infected individuals may excrete many millions of oocysts each day during the acute stage⁴. Infected human and animal hosts usually contaminate potable water, food and formities. Open sewage systems provide the commonest routes of discharge of pathogens into freshwater in urban areas. In addition, human and animal waste points constitute a major source.

The genus Cryptosporidium is a phenotypically and genotypically heterogenous assemblage of largely morphologically identified species and genotypes. Fourteen species and twenty-one C. parvum genotypes are currently recognized¹³.

Cryptosporidium transmission occurs at a high frequency in day care centers where children are clustered within classrooms, share toilets and common play areas, or necessitate frequent diaper changing¹⁴.

Materials And Methods

Study design: A cross-sectional study was conducted on patients that attended the Federal Staff Hospital, Abuja, from June 2005 to April 2006, in order to determine the prevalence of C. parvum. Stool samples were collected from recruited members and placed ^{in disposable plastic cups, with subsequent addition of 10% formalin as a preservative before analysis, and in accordance with institutional ethical guidelines. All the stool samples for parasitological investigation were processed in the laboratory of the hospital.}

Stool examination: the parasitic infections were diagnosed by examination of stool specimens as fresh wet mounts, using formol ether concentration techniques and modified acid-fast stain. Fresh and concentrated stool specimens were examined as saline wet mounts to detect oocysts. Air-dried smears from fresh stool samples were fixed and stained by a modified acid-fast stain to detect C. parvum.

Statistical Analysis: Difference between proportions was evaluated using the chi-square test. Student T-test for continuous parameter for mean age was performed according to Student, 1907¹⁵. Statistical significance was achieved if P < 0.05.

Results

The stools of a total of 354 patients were examined for the presence of C. parvum infection. The females were more infected than the males, 18 (10.84%) versus 14 (7.45%). Statistical analysis showed an insignificant difference in the association between sexes and C. parvum infection (?² =1.233, P >0.05. df = 1)(See Table 1). In the individuals with diarrhoea, the age group of 41-50 years had the highest prevalence of C. parvum infection (3, 33.33%), followed by those that were >50 years of age (2, 20.0%) and 31-40 years (3, 18.75%). Statistically there exists no significant difference in the trend (?²=2.557, P>0.05, df=4)(See table 2). In non diarrhea individuals, those that were aged 31-40 years had the highest prevalence of C. parvum infection (4, 10.53%), followed by those that were aged >50 years (1, 7.69%). It was not statistically significant (?²=4.711, P>0.05, df=4)(See table 3).

The mean age of the patients was 22.96 + 0.1 years (range 1-90 years; SD 0.93), with 188 males and 166 females. Diarrhea was present in 129 patients and 225 had no diarrhea. Among those with diarrhea, 21 had C. parvum while 11 did not have diarrhea but had C. parvum.

Discussion

The present study, to the best of our knowledge, is the first report of the detection of C. parvum in Abuja. The isolation rate of C. parvum in diarrhea stool was high in our study (16.28%) compared to other studies^16,17 and correlates with other reports^18-20. There was no significant difference in the prevalence among the cases and controls, indicating an existing high risk of infection by this parasite in Abuja. Some other studies highlighted C. parvum as the predominant pathogen with significant association to diarrhea cases.^{17,19, 21} The high prevalence of Cryptosporidium among both control and test population was observed ealier²⁰. In a study in India, a prevalence of 25.2% was reported for diarrhea and 4.7% for controls²². In another study in India, Cryptosporidium was found in 40% of cases. C. parvum was detected in 20.6% of chronic diarrhea and 2.5% in non diarrhea cases²³. A prevalence of 30% was reported in Zaire²⁴. In a study on children in Uganda, 25% was reported for diarrhea and 8.5% for non-diarrhea²⁵. In Malawi, in 11% of individuals with diarrhea, C. parvum were detected²⁶. Patients seropositive for HIV who presented with chronic diarrhea had an infection rate of 32% for Cryptosporidium. In Lusaka, Zambia individuals had Cryptosporidium in 32% of cases²⁷.

This organism usually causes a self-limiting illness in immunocompetent individuals, but as the immune status of the patient falls they are known to cause life-threatening, profuse, watery diarrhea²⁸. The role of C. parvum as a cause of acute ^{diarrhea in developing countries is well documented29.}

The epidemic potential of cryptosporidial diarrhea has been documented^30,31, as have the implications of Cryptosporidiosis in HIV/AIDS and immunosuppressed individuals.^19,32 Cryptosporidiosis can be acquired at any time during the course of HIV infection. Major mortality and morbidity occur in patients with multiple parasites and CD4 count below 116 /cmm³³.

The present study documented the prevalence of C. parvum with diarrhea in Abuja. C. parvum was associated with diarrhea more often than in the control cases studied. This study has provided additional baseline information on the prevalence of C. parvum infection in Nigeria as part of developing strategies towards effective management of C. parvum individuals. In conclusion, this study laid credence on the importance of routine stool cultures for the detection of coccidian parasites, especially if the patients are immunocompromised.

Figure 1

Table 1: Gender related prevalence of C. parvum in Abuja, Nigeria.

Figure 2

Table 2: Age and diarrhea related prevalence of C.parvum in Abuja, Nigeria.

Figure 3

Table 3: Age and Non diarrhea related prevalence of C. parvum in Abuja, Nigeria.

Acknowledgement

This work was conducted with the technical assistant of Mrs. Mba G., Mr. Oga E.O. of Federal Staff Hospital, Abuja. The authors are grateful to the physicians in the hospital for their cooperation during the study.