Evaluating the Prevalence of Malaria Parasite Infection among Adults in Wetlands Using Nested PCR and High Resolution Melting Analysis

Background: Wetlands serve as breeding grounds for mosquitoes, the vector of malaria Plasmodium. Effective detection of Plasmodium infection requires a very sensitive method.

Aim: The aim of the present study was to evaluate the prevalence of malaria parasite infection in Sagbama LGA, Bayelsa State using nested PCR and high resolution melting analysis (HRMA) technique in comparison with microscopy.

Methods: A community based cross sectional study design was employed to randomly select 206 study participants. DNA was extracted from 200 ⴗl of whole blood of each participant and a set of primers was used to target and amplify the 18S rRNA gene of Plasmodium falciparum in both molecular methods.

Result: The prevalence of Plasmodium falciparum infection by microscopy was 33.01% (5.8% asymptomatic, 17% mild and 10.2% severe malaria).The prevalence of malaria parasite infection by nested genomic PCR was 71.36% (asymptomatic, 42.20% mild, 18.93%and severe malaria, 10.19%). Prevalence of malaria parasite infection by high resolution melting analysis 92.71% (asymptomatic, 63.59%, mild, 18.93% and severe, 10.19%). All the study participants that were positive for microscopy and nested genomic PCR were also positive for high resolution melting analysis. There were 59.71% and 21.36% false negatives by microscopy and nested PCR respectively. McNemar`s test for pair-wise performance comparisons among the different methods was statistically significant (p < 0.001). High parasite density (19927 ± 749 parasites/µl blood) and hyper parasite density (103667 ± 5214 parasites/ⴗl of blood) were found among asymptomatic and severe malaria subjects (P < 0.000).

Conclusion: In conclusion, a high malaria parasite infection prevalence of 92.72% was found in Sagbama LGA. This requires urgent attention especially asymptomatic malaria. HRMA was the most sensitive molecular method and is therefore recommended for future molecular detection of malaria infection.