Performance assessment of a widely used rapid diagnostic test CareStart™ compared to microscopy for the detection of Plasmodium in asymptomatic patients in the Western region of Cameroon

Use of pesticides and risk perception of environmental contamination by farmers surrounding the Menoua River (West Cameroon)

Cameroonian farmers regularly use pesticides in farming to control pests, particularly along the riverbank of the Santchou agricultural area. The aim of this study was to assess the perception of farmers in West Cameroon (Santchou area) regarding the contamination risk in aquatic environments from the use of pesticides. A cross-sectional study via questionnaires was conducted among 150 selected farmers who cultivated fields along the banks of the Menoua River. Almost all the farmers (90%) used pesticides regularly, particularly herbicides, insecticides, and fungicides to combat pests. The main pesticides used were glyphosate, paraquat, dieldrin, chlorpyrifos-ethyl, copper oxide, and mancozeb. Farmers who cultivated larger areas of land or who had mixed culture crops tended to use pesticides more often (p < 0.001). The use of river water by farmers was correlated with pesticide use (p = 0.010). Most of the pesticide users (90%) did not use protective equipment when spraying the crops. The farmers' perceptions of the risk of pesticide contamination of the river water (p = 0.002) or fish (p = 0.008) did not influence their actions. A correlation was found among pesticide users who believed that there was a risk of river contamination (45%) or fish contamination (42%) and intensive pesticide application during the rainy season (61%) or non-respect of the prescribed pesticide application doses (51%; p = 0.002). Farmers who regularly or occasionally consumed fish used pesticides more often than those who did not consume fish from the river. The findings of this study emphasize the need for education of farmers in Santchou to prevent the risk of environmental contamination and health hazards from increased dietary and/or dermal pesticide exposure. Integr Environ Assess Manag 2023;19:1600-1608. © 2023 SETAC.

High prevalence of asymptomatic Plasmodium falciparum malaria in Makenene, a locality in the forest-savannah transition zone, Centre Region of Cameroon

Malaria transmission and prevalence is still not well documented across Cameroon particularly in medium-sized cities or localities representing high transit zone. Different risk factors could be associated with persistence malaria transmission such as population movement from high to low transmission settings. A cross-sectional community-based study was carried out to determine malaria prevalence and risk factors in Makenene, a small city in a forest-savannah which is a crossroads between different parts of the country where travellers usually stop-over day and night to rest. Using malaria diagnostic test (mRDTs from SD-BIOLINE) and microscopy (thin and thick blood smears), 406 participants from 237 households were tested for malaria infection. The prevalence of malaria was high irrespective of the detection method: mRDT (41.87%) or microscopy (38.42%). At household level, 46.41% of households had at least one case of malaria with an average of 1.41 infected individuals per household. Parasite density was also high with the majority of infected individuals (64.74%) bearing more than 500 parasites/μl. Only Plasmodium falciparum was found. The chances of being infected with malaria parasites was almost the same for all participants irrespective of the sleeping behavior, bednet usage, house type and environmental factors. The study supports high malaria transmission in the locality and the need for additional studies on vectors bionomics and transmission patterns.

Influence of tillage systems and sowing dates on the incidence of leaf spot disease in Telfairia occidentalis caused by Phoma sorghina in Cameroon

The production and leaf quality of Telfairia occidentalis in Cameroon are gravely threatened by leaf spot disease. A field study was conducted in July 2019 and 2020 to determine the influence of tillage systems and sowing dates on the incidence of Telfairia occidentalis leaf spot caused by Phoma sorghina. A randomized block design with three replications and four planting dates was used. The soil physicochemical properties were also determined. Data for disease incidence were registered once every two weeks and submitted to generalized linear model for statistical analysis. The means were separated by Duncan's multiple range test at a 95% confidence interval. Calculations for disease incidence and statistical analysis were conducted using the Microsoft Excel program and SPSS version 23, respectively. Statistical analysis revealed that the zero tilled field generally registered a lower leaf spot disease incidence than the tilled field, which was highly significant (p ≤ 0.05). In addition, the second sowing date in the zero tilled field proved to be better in terms of low disease incidence than other sowing dates employed in the study. Therefore, to minimize the devastating effects of leaf spot disease, zero tillage coupled with the second sowing date could be exploited.

Assessment of a Commercial Real-Time PCR Assay (Vitassay qPCR Malaria 5 Test) to Detect Human Malaria Infection in Travelers Returning to France

Malaria is the most common human parasitic disease in the world with the highest morbidity and mortality. Due to the severity of malaria caused by Plasmodium falciparum and the urgency of therapeutic management, quick and reliable diagnosis is required for early detection. Blood smear microscopy remains the gold standard for malaria diagnosis. Molecular diagnosis techniques are the most sensitive and specific in cases of low parasitaemia and in the detection of mixed infections. The purpose of this study was to evaluate a new commercial test involving the molecular diagnostic technique to detect the five human Plasmodium species. The Vitassay qPCR Malaria 5 test is based on the multiplex real-time PCR of a conserved target region of the 18S rRNA gene for the five human Plasmodium species. A total of 190 samples collected from imported cases of malaria were diagnosed using this test and compared against a homemade reference real-time PCR. The sensitivities of the Vitassay qPCR Malaria 5 test for all Plasmodium species ranged from 93.8% to 100% and specificity ranged from 97.7% to 100%. Based on these criteria, this test is recommended for the diagnosis of the human Plasmodium species.