Biochemistry, University of Yaounde I
June, 2013



Microsporidia are obligate unicellular parasites causing disease predominantly in immunocompromised patients. Several species of these parasites cause disease in both immunocompromised and immunocompetent patients. There is a wide range of clinical manifestations of infections due to microsporidia. Enterocytozoon bieneusi is the most common species causing chronic diarrhoea in immunocompromised patients. Members of the Encephalitozoon species, which include E. intestinalis, E. hellem and E. cuniculi, cause disseminated microsporidian infections. Treatment of microsporidiosis depends on species identification. Albendazole is an effective treatment against Encephalitozoon species, meanwhile no effective treatment against E. bieneusi has been found. Research on these parasites has focused mostly on immunocompromised patients whereas little is known about this infection in healthy or immunocompetent subjects. The epidemiology in immunocompetent individuals is still under investigation. There is still debate as whether microsporidia remains persistent in healthy immunocompetent subjects and is reactivated in conditions of immuno-suppression. PCR is an effective tool for species identification of microsporidia. The main objective of this study was to determine the prevalence of microsporidia by PCR in both healthy asymptomatic individuals and in immunocompromised patients residing in Yaoundé.

This was a prospective descriptive cross-sectional study conducted from September 2012 to April 2013. Stool samples were collected from 37 HIV-positive patients at the Jamot Hospital Yaoundé and from 127 asymptomatic healthy individuals in 4 urban neighbourhoods of Yaoundé (Efoulan, Etoug-ebe, Essos, and Obili). Samples were subjected to PCR assay using species-specific primers EBIEF1/EBIER1 for E. bieneusi, SINTF/SINTR for E. intestinalis, EHELF/EHELR for E. hellem, and ECUNF/ECUNR for E. cuniculi, which amplify small subunit ribosomal RNA (SSU rRNA) of these microsporidian species.
Data were analysed using Epi-info version 7.1.14 and SPSS version 20.0. Fisher-Exact test was used for comparison of categorical Data. Associated risks were calculated at 95% confidence interval. Statistical significance was set a P<0.05.

Eleven of the 164 (6.7%) subjects studied had microsporidian: six of 127 (4.7%) healthy participants, and five of 37 (13.5%) immunocompromised participants.
The prevalence of microsporidia was greatest in healthy children less than 10 years old. Microsporidia were detected only in subjects 20-50 years old that were HIV-infected.
The male to female distribution of persons infected with microsporidia was 1:1.2; the difference was not statistically significant (p=0.75). Microsporidia infections were detected in Efoulan, Etoug-ebe, and Essos, but not in Obili. Efoulan had the highest rate of infection.
All four microsporidian species tested were present: E. bieneusi (4; 36.4%), E. intestinalis (2; 18.2%), E. hellem (3; 27.3%), and E. cuniculi (2; 18.2%). All four species were also detected in stool samples from healthy participants.
We found an association between microsporidiosis and the use of untreated well water for drinking (OR=5.5), which was statistically significant (p=0.014). There was an association between keeping pets and microsporidiosis (OR=5.3) which was statistically significant (p=0.01).


1. There are four microsporidian species present in urban neighbourhoods of Yaoundé: Enterocytozoon bieneusi, Encephalitozoon intestinalis, Encephalitozoon cuniculi and Encephalitozoon hellem.
2. 13.5% of the HIV-positive participants had Enterocytozoon bieneusi, Encephalitozoon intestinalis, or Encephalitozoon hellem.
3. The distribution of microsporidia in Yaoundé is irrespective of age or gender.
4. There is a five fold higher chance of microsporidiosis with consumption of well water or animal co-habitations.

• To the scientific community:
To shed more light on our findings, similar studies should be carried-out with participants who tested negative for HIV in Yaoundé and other part of Cameroon.
To clinicians
• To include screening for microsporidia in routine workups for Immunocompromised patients with gastrointestinal symptoms.