Point prevalence of asymptomatic Plasmodium infection and the comparison of microscopy, rapid diagnostic test and nested PCR for the diagnosis of asymptomatic malaria among children under 5 years in Ghana.

BACKGROUND: Plasmodium infection among children is a serious public health problem. Asymptomatic malaria infection among humans serves as a significant reservoir for transmitting Plasmodium to uninfected Anopheles mosquitoes, fueling malaria endemicity and asymptomatic malaria may progress to clinical malaria. Therefore, prompt and accurate diagnosis of malaria infection is crucial for the management and control of malaria, especially in endemic areas. This study assessed the point prevalence of asymptomatic malaria infection and evaluated the performance of malaria Rapid Diagnostic Tests (RDT), light microscopy and nested PCR (nPCR) for the diagnosis of asymptomatic malaria infection in a paediatric population in the Atwima Nwabiagya North district, Ghana. METHODS: This cross-sectional study enrolled 500 asymptomatic children aged ≤ 5 years. After consent was obtained from a parent, blood samples were collected from each participant to assess for Plasmodium infection based on histidine rich protein-2 (pfHRP-2)-based malaria RDT, light microscopy and nPCR. RESULTS: The point prevalence of asymptomatic malaria by microscopy, RDT, and nPCR were 116/500 (23.2%), 156/500 (31.2%), and 184/500 (36.8%), respectively. Using nPCR as the reference, RDT presented with a perfect sensitivity (100.0%), specificity (100.0%), accuracy (100.0%), and reliability (100.0%) in detecting asymptomatic P. falciparum infection. Likewise, microscopy presented with an excellent specificity and high accuracy in detecting both P. falciparum (100.0%; 85.6%) and P. malariae (100.0%; 100.0%). However, the sensitivity (56.4%) and reliability (56.4%) of microscopy was low for both P. falciparum. CONCLUSION: The findings of this study indicate a high point prevalence of asymptomatic Plasmodium infection among children in Atwima Nwabiagya North district, Ghana. In the absence of the more sensitive PCR, pfHRP-2-based malaria RDT provides substantial diagnostic sensitivity, specificity, accuracy and reliability and is superior to microscopy.

Prevalence and the evaluation of culture, wet mount, and ELISA methods for the diagnosis of Trichomonas vaginalis infection among Ghanaian women using urine and vaginal specimens.

BACKGROUND: The services of most clinical laboratories in Africa regarding the diagnosis of Trichomonas vaginalis are largely dependent on the urine direct wet-mount method. However, the exclusive use of urine-based detection may not be appropriate. The culture method is considered the "gold standard" for the diagnosis of T. vaginalis. However, this method has a relatively longer turn-around time and is limited by non-viable organisms in the specimen. This study assessed the prevalence of T. vaginalis and its associated risk factors and evaluated its diagnosis using urine and vaginal samples from symptomatic female out-patients by culture, direct wet-mount, and ELISA method respectively. METHODS: This cross-sectional study was conducted at the Obstetrics and Gynaecology department of the Manhyia District hospital (MDH) and Komfo Anokye Teaching Hospital (KATH), Ghana. Ghanaian sexually active female adults between the ages of 18 and 50 years old were recruited for this study. Vaginal (HVS) and urine samples were collected from each participant, and T. vaginalis infection was assessed based on culture, direct wet mount, and ELISA methods. RESULTS: The prevalence of T. vaginalis infection based on the ELISA method, HVS culture, and HVS wet mount were 7.2%, 5.0%, and 1.7%, respectively. Urine culture presented with a 0.6% prevalence rate while urine direct wet mount detected no positive case. There was no statistically significant association between demographic and clinical characteristics and T. vaginalis infection, except for subjects presenting with abdominal pain [OR = 5.42, 95% CI (1.35-21.73), p = 0.017]. Using HVS culture as the reference, ELISA performed best compared to the other methods assessed in this study, presenting with the highest sensitivity [88.9%, 95% CI (54.0-99.8)], specificity [97.1%, 95% CI (93.1-98.9)], AUC (93.0%), and accuracy (96.7%). CONCLUSION: The prevalence of T. vaginalis infection is high among women in Ghana. With the exception of abdominal pain, there is no significant association between demographic and clinical characteristics and T. vaginalis infection. In the event where the culture method is unavailable or when rapid diagnosis is required, antigenic detection using ELISA is the most accurate for the diagnosis of T. vaginalis infection in women compared to urine wet-mount/culture and the HVS wet-mount method.