Conference abstract
Identification of malaria species among asymptomatic reservoirs in the district of Nkolbisson
Pan African Medical Journal - Conference Proceedings. 2023:18(86).03
Oct 2023.
doi: 10.11604/pamj-cp.2023.18.86.2040
Archived on: 03 Oct 2023
Contact the corresponding author
Keywords: Asymptomatic malaria, children, microscopy, nested PCR, Nkolbisson District
Poster
Identification of malaria species among asymptomatic reservoirs in the district of Nkolbisson
Oben Ayem OL1, Ngomtcho Sen CH1,2,&, Mbange Ekollo AH3,4, Nguetsop Dongue JB1, Fomboh Tah C3, Kamga HL1
1Department of Microbiology, Hematology et Immunology, Faculty of Medicine and Pharmaceutical Sciences, University of Dschang, Dschang, Cameroon, 2Molecular Biology and Immunology Unit, National Public Health Laboratory (NPHL), Yaoundé, Cameroon, 3Biotechnology Center, University of Yaoundé I, Messa, Yaoundé Cameroon, 4University Institute of Technology, University of Ngaoundéré, Ngaoundéré, Cameroon
&Corresponding author
Introduction: malaria remains a major public health problem worldwide, causing death in children under the age of five. Depending on clinical presentation, the absence of overt malaria symptoms and the presence of low parasitemia suggest a complex dynamic between different Plasmodium species, often misdiagnosed and treated as single species. This makes asymptomatic individuals a hidden reservoir contributing to malaria transmission and an obstacle to malaria elimination efforts. The objective was to determine the prevalence of asymptomatic malaria infections and characterize single and mixed Plasmodium species in children in Nkolbisson, Yaoundé, Cameroon.
Methods: this cross-sectional study was conducted between October 2022 and July 2023. 325 children aged between 6 and 120 months were recruited after obtaining authorization from their parents. Samples were collected in 6 health areas of the district. The Capillary blood samples were taken from these children to detect the presence of Plasmodium by RDT and microscopy. For molecular identification of these species, venous blood was impregnated on filter paper Whatman 903 and transported to the Laboratory for Public Health Research Biotechnologies of the UYI. Plasmodial DNA was extracted using the Chelex-100 boiling method, then amplified by nested PCR targeting Plasmodium's 18S rRNA genomic region.
Results: the mean age of the population was 65.09 ± 32.52 months (95% CI. 6–120) and a mean axillary temperature of 36.76 ± 0.24°C. The prevalence of Plasmodium infections in asymptomatic children was 6.5% (21/325) by microscopy, 29.5% (96/325) by RDT and 32.92% (107/325) by nested PCR. Of the 107 asymptomatic cases revealed by nested PCR, 86 (80.37%) were single P. falciparum infections, 5 (4.67%) single P. malariae (5/107), and 1 (0.93%) P. ovale. Double infections with P. falciparum /P. malariae were found in 14 (13.08%) cases, while triple P. falciparum/P. malariae /P. ovale in only 1 (0.93± 32.52%) case. Using nested PCR as the reference method, microscopy had a sensitivity and specificity of 15.89 % and 98.17% respectively compared to RDT which had a sensitivity and specificity of 68.75% and 82.10% respectively.
Conclusion: TDR remains a better option for diagnosing asymptomatic cases in Yaoundé, which has a year-round malaria transmission. Only a few cases of mixed infections were recorded, which may confound the detectability of asymptomatic malaria cases, especially with P. falciparum and P. malariae, which were, however, non-negligible in the study.
Identification of malaria species among asymptomatic reservoirs in the district of Nkolbisson
Oben Ayem OL1, Ngomtcho Sen CH1,2,&, Mbange Ekollo AH3,4, Nguetsop Dongue JB1, Fomboh Tah C3, Kamga HL1
1Department of Microbiology, Hematology et Immunology, Faculty of Medicine and Pharmaceutical Sciences, University of Dschang, Dschang, Cameroon, 2Molecular Biology and Immunology Unit, National Public Health Laboratory (NPHL), Yaoundé, Cameroon, 3Biotechnology Center, University of Yaoundé I, Messa, Yaoundé Cameroon, 4University Institute of Technology, University of Ngaoundéré, Ngaoundéré, Cameroon
&Corresponding author
Introduction: malaria remains a major public health problem worldwide, causing death in children under the age of five. Depending on clinical presentation, the absence of overt malaria symptoms and the presence of low parasitemia suggest a complex dynamic between different Plasmodium species, often misdiagnosed and treated as single species. This makes asymptomatic individuals a hidden reservoir contributing to malaria transmission and an obstacle to malaria elimination efforts. The objective was to determine the prevalence of asymptomatic malaria infections and characterize single and mixed Plasmodium species in children in Nkolbisson, Yaoundé, Cameroon.
Methods: this cross-sectional study was conducted between October 2022 and July 2023. 325 children aged between 6 and 120 months were recruited after obtaining authorization from their parents. Samples were collected in 6 health areas of the district. The Capillary blood samples were taken from these children to detect the presence of Plasmodium by RDT and microscopy. For molecular identification of these species, venous blood was impregnated on filter paper Whatman 903 and transported to the Laboratory for Public Health Research Biotechnologies of the UYI. Plasmodial DNA was extracted using the Chelex-100 boiling method, then amplified by nested PCR targeting Plasmodium's 18S rRNA genomic region.
Results: the mean age of the population was 65.09 ± 32.52 months (95% CI. 6–120) and a mean axillary temperature of 36.76 ± 0.24°C. The prevalence of Plasmodium infections in asymptomatic children was 6.5% (21/325) by microscopy, 29.5% (96/325) by RDT and 32.92% (107/325) by nested PCR. Of the 107 asymptomatic cases revealed by nested PCR, 86 (80.37%) were single P. falciparum infections, 5 (4.67%) single P. malariae (5/107), and 1 (0.93%) P. ovale. Double infections with P. falciparum /P. malariae were found in 14 (13.08%) cases, while triple P. falciparum/P. malariae /P. ovale in only 1 (0.93± 32.52%) case. Using nested PCR as the reference method, microscopy had a sensitivity and specificity of 15.89 % and 98.17% respectively compared to RDT which had a sensitivity and specificity of 68.75% and 82.10% respectively.
Conclusion: TDR remains a better option for diagnosing asymptomatic cases in Yaoundé, which has a year-round malaria transmission. Only a few cases of mixed infections were recorded, which may confound the detectability of asymptomatic malaria cases, especially with P. falciparum and P. malariae, which were, however, non-negligible in the study.
