Detection of Wuchereria bancrofti in human blood samples and mosquitoes in Matayos, Busia County-Kenya.

Lymphatic filariasis is a mosquito borne disease which leads to abnormal painful enlarged body parts, severe disability and social stigma. We screened Wuchereria bancrofti in Matayos constituency in Busia County. Blood samples were collected from 23 villages selected purposively based on clinical case reports. Finger prick and/or venous blood sampling and mosquito collections was carried out. Antigenaemia and filarial DNA prevalence were determined. Infection rates on mosquito pools were estimated and SPSS version 26 was used for descriptive statistics analysis. A total of 262 participants were recruited, 73.3% (n = 192) of the participants had no symptoms, 14.1% (n = 5.3) had swollen legs, 5.3% (n = 14) had painful legs and 3.8% (n = 10) with scrotal swellings. Average antigenemia prevalence was 35.9% (n = 94) and DNA prevalence was at 8.0% (n = 21). A total of 1305 mosquitoes were collected and pooled into 2-20 mosquitoes of the same species and from the same village. Two pools out of 78 were positive for filarial DNA with a minimum infection rate of 0.15%. From this study, antigenaemia and infected mosquitoes are an indication of active transmission. The clinical signs are evidence that filarial infections have been in circulation for over 10 years. The global climate change phenomenon currently happening has been shown to adversely affect the transmission of vector borne diseases and is likely to increase lymphatic filariasis transmission in the area. This study therefore recommends further screening before Mass Drug Administration, morbidity management and enhanced mosquito control Programmes are recommended in the study area.

Mapping of Podoconiosis Cases and Risk Factors in Kenya: A Nationwide Cross-sectional Study.

Podoconiosis is a type of tropical lymphedema that is clinically distinguished from lymphatic filariasis (LF) because it is ascending and commonly bilateral but asymmetric. The disease is a result of a genetically determined inflammatory reaction to long-term exposure to mineral particles in irritant red clay soils derived mainly from volcanic soils. We conducted the first nationwide mapping of the prevalence and risk factors of podoconiosis in Kenya. We performed a population-based cross-sectional survey to determine the national prevalence of podoconiosis and included 6,228 individuals from 48 villages in 24 sub-counties across 15 counties. Participants answered a questionnaire about the history of symptoms compatible with podoconiosis, received a point-of-care antigen test, and underwent a physical examination if they had lymphedema. A confirmed case of podoconiosis was defined as a case in a resident of the study village who had lower limb bilateral and asymmetric lymphedema lasting more than 1 year, negative test results for Wuchereria bancrofti antigen, and other causes of lymphedema ruled out. Of all the individuals surveyed, 89 had lymphedema; of those, 16 of 6228 (0.3%; 95% confidence interval [CI], 0.1-0.5) were confirmed to have podoconiosis. A high prevalence of podoconiosis was found in western (Siaya, 3.1%; Busia, 0.9%) and central (Meru, 1.1%) regions, and a low prevalence was observed in northern (Marsabit, 0.2%), eastern (Makueni, 0.2%), and coastal (Tana River, 0.1%) regions. The identified risk factors were age 56 years or older (adjusted odds ratio [aOR], 5.66; 95% CI, 2.32-13.83; P < 0.001) and rarely wearing shoes (aOR, 18.92; 95% CI, 4.55-78.71; P < 0.001). These results indicated that the podoconiosis prevalence is low and localized in Kenya; therefore, elimination is achievable if appropriate disease prevention, management, and behavioral strategies are promoted.

Soil iron and aluminium concentrations and feet hygiene as possible predictors of Podoconiosis occurrence in Kenya.

BACKGROUND: Podoconiosis (mossy foot) is a neglected non-filarial elephantiasis considered to be caused by predisposition to cumulative contact of uncovered feet to irritative red clay soil of volcanic origins in the tropical regions. Data from structured observational studies on occurrence of Podoconiosis and related factors are not available in Kenya. METHODOLOGY/PRINCIPAL FINDINGS: To establish the occurrence and aspects associated with Podoconiosis, a cross-sectional survey was implemented in an area located within 30 km from the foot of volcanic Mount Longonot in the Great Rift Valley in Kenya. Five villages and 385 households were selected using multistage and systematic random sampling procedures respectively during the survey. Podoconiosis was determined by triangulating (1) the clinical diagnosis, (2) molecular assaying of sputum samples to rule out Wuchereria bancrofti microfilaria and (3) determining the concentration of six elements and properties in the soil known to be associated with Podoconiosis. A structured questionnaire was used to identify possible risk factors. Univariable and multivariable Poisson regression analyses were carried out to determine factors associated with Podoconiosis. Thirteen participants were clinically positive for Podoconiosis giving an overall prevalence of 3.4%. The prevalence ranged between 0% and 18.8% across the five villages. Molecular assay for W. bancrofti test turned negative in the 13 samples. The following factors were positively associated with the Podoconiosis prevalence (P<0.1) in the univariable analyses: (i) age, (ii) gender, (iii) education level, (iv) frequency of washing legs, (v) frequency of wearing shoes, (vi) soil pH, and (vii) village. Unexpectedly, the concentration of soil minerals previously thought to be associated with Podoconiosis was found to be negatively associated with the Podoconiosis prevalence (P<0.1). In the multivariable analyses, only frequency of wearing shoes and village turned out significant (P≤0.05). By modeling the different soil mineral concentrations and pH while adjusting for the variable frequency of wearing shoes, only iron concentration was significant and in the negative dimension (P≤0.05). However, controlling for Iron, Aluminum concentrations turned significant. CONCLUSION/SIGNIFICANCE: This study has pointed to a hitherto unreported occurrence of Podoconiosis cases and has contributed to the baseline knowledge on the occurrence of Podoconiosis in Kenya. Consistent with many studies, wearing shoes remain an important risk factor for the occurrence of the disease. However, our findings are inconsistent with some of the hitherto postulations that associate Podoconiosis prevalence with certain minerals in the soil in other regions in Africa. These findings provide new beginnings for the cross-disciplinary research of Podoconiosis in environmental health, socio-ecology and ecological niche and geo-spatial modeling and prediction.