Molecular profiling of human malaria parasites among individuals suspected for malaria in three geo-ecological facets of malaria transmission in Cameroon.

Malaria still remains a major public health problem in Cameroon. Although P. falciparum is the predominant plasmodium species in the country, there is growing evidence of non-falciparum malaria especially vivax malaria which was previously thought to be absent. This suggests these infections are being underdiagnosed. However, there is limited data on the distribution of malaria parasite species in circulation in Cameroon posing a challenge in the true estimation of malaria burden. As a consequence, further investigation of the local epidemiology of malaria in Cameroon is important. A cross-sectional study was conducted from June 2022 to August 2023 in three geo-ecological regions of Cameroon (Sahelian zone, Humid Forest and Western Highlands). Blood samples were collected from individuals suspected of malaria and dried blood spots (DBS) prepared. DNA was extracted from a total of 1390 DBS using Chelex-100 method and tested by nested PCR targeting the species-specific 18srRNA gene. A high prevalence of malaria (682/1390, 49.06%) was recorded. Single species infection accounted for 651/682 cases (95.45%) with P. falciparum mono infection being the most represented across all study sites (630/682, 92.38%). The proportion of all non-falciparum infections was 8.36% (57/682) and P. ovalecurtisi was the most frequent (20/57) followed by P. ovale wallikeri (18/57). P. malariae mono infection was the most common non-falciparum mono infection. P. vivax was detected exclusively as a coinfection with P. falciparum (2/682; 0.29%). Coinfections accounted for 31/682 cases (4.55%) with P.falciparum / P. ovalecurtisi identified as the most frequent. Significant determinants of malaria infection included age and geo-ecological zone. The age group 10-20 years was the most susceptible to malaria infection (AOR = 1.87, 95% CI = [1.06-3.30], p.value = 0.03) and the Sahelian zone the most at risk (AOR = 1.97, 95%CI = [1.41-2.70], p.value < 0.001).