Distribution of falciparum and non-falciparum malaria among symptomatic malaria patients in Dschang, West Region of Cameroon.

BACKGROUND

Malaria is a vector-borne parasitic disease that continues to be a global public health threat. Five different species of the genus Plasmodium (P. falciparum, P. malariae, P. ovale curtisi, P. ovale wallikeri, and P. vivax) cause malaria in Sub-Saharan Africa. Previous cross-sectional surveys from 2013 and 2017 indicated the circulation of P. vivax in the West region of Cameroon, prompting an investigation into the prevalence of all falciparum and non-falciparum malaria parasite species in this region.

METHODS

A cross-sectional facility-based study targeting both adult and children in which we recruited 431 clinically suspected cases of malaria from three health centres in the West region of Cameroon in 2020. Socio-demographic, clinical data, and dried blood spots (DBS) were collected from all consenting patients. Parasite DNA was extracted from DBS for real-time PCR amplification of species-specific Plasmodium 18S rRNA for P. falciparum, P. ovale, P. malariae, and P. vivax. In addition, P. ovale was further sub-classified into P. ovale curtisi or P. ovale wallikeri using qPCR. The prevalence of different species was measured.

RESULTS

Among the 431 samples, the overall malaria prevalence was 54.8% [95% CI: 50.1-59.8] (236/431). Of these, 53.4% [95% CI: 48.7-58.5] were infected with P. falciparum, 4% [95%CI: 2.2-5.6] with P. ovale, and 0.9% [95% CI: 0.2-1.7] with P. malariae. No P. vivax was detected. Mixed infections were common, with 8.9% of the infections harbouring more than one Plasmodium species. A total of 5 P. ovale and 1 P. malariae mono-infections were detected. Of the 17 P. ovale infections, 12 were successfully genotyped, with 6 P. ovale curtisi, 3 P. ovale wallikeri, and 3 a mixture of the species.

CONCLUSIONS

While falciparum remains the dominant malaria parasite species among acute febrile illness cases, non-falciparum malaria is also commonly found in Dschang, both as a co-infection with P. falciparum and as mono-infections. Both subspecies of P. ovale are present in the region. Continued monitoring of non-falciparum species is needed for understanding malaria burden in West Cameroon.