Cutaneous leishmaniasis in Yemen: Epidemiology, knowledge, attitude and practices among rural populations, and genetic diversity of Leishmania Tropica in Utmah District / Manal Ali Saleh Al-Ashwal

Manal Ali Saleh , Al-Ashwal (2024) Cutaneous leishmaniasis in Yemen: Epidemiology, knowledge, attitude and practices among rural populations, and genetic diversity of Leishmania Tropica in Utmah District / Manal Ali Saleh Al-Ashwal. PhD thesis, Universiti Malaya.

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Abstract

Cutaneous leishmaniasis (CL) is a major public health problem in Yemen and is hyperendemic in many rural areas across the country. However, there is a dearth of research investigating the epidemiology of CL in the local communities where it is endemic. This study aimed to investigate the epidemiology (prevalence, risk factors and population’s knowledge, attitude and practices towards CL), and genetic diversity of CL-causing Leishmania species among rural populations in Utmah district, western Yemen. A community-based cross-sectional survey, followed by unmatched case-control comparisons, was conducted among 612 participants from 289 randomly selected households in four rural sub-districts. A total of 223 participants were included in the case-control analysis. Skin scrapping/slits samples were collected from 81 individuals found with suspected active CL lesions while skin slits and/or blood samples were collected from 122 animals. The samples were examined by microscopy and internal transcribed spacer 1 (ITS-1) nested PCR. Genetic structure and haplotype diversity were analysed. Demographic, socioeconomic, environmental and KAP related data were collected using a pre-tested questionnaire. Overall, 8.7% and 16.4% of the human and animal (goats, cows, donkeys, bulls, rabbits, bats, dogs and rats) samples were found positive, with Leishmania tropica was the only causative agent identified. Multivariate hierarchical logistic regression analyses showed that being ≤ 10 years old, being female, living in poor housing conditions with cracked walls, living in the presence of other family members with typical ulcerating skin diseases, sleeping outside and keeping livestock on the ground floor of the house were factors significantly associated CL. A total of 51.2%, and 33.9% of the participants had good knowledge about CL and sandflies, respectively. Moreover, only 38.1% and 16.3% had a positive attitude and good CL-related practices, respectively. The phylogenetic analysis of 54 human and animal sequences segregated six different L. tropica haplotypes, with low haplotype diversity (Hd = 0.242 ± 0.077) and no genetic differentiation (FST = 0.050). The genetic diversity analysis for 367 L. tropica sequences (54 obtained by this study plus 313 sequences were retrieved from GenBank) showed high haplotype diversity (0.605 ± 0.028) but low nucleotide diversity (0.005 ± 0.0004), with significant Tajima’s D (-2.583) and Fu’s Fs tests (-33.210). The median-joining haplotype network produced 54 haplotypes with one dominant haplotype. Overall, the study revealed an alarmingly high prevalence of CL and identified related key risk factors among the rural population in Utmah district. Also, the study demonstrated poor levels of KAP about CL and sandfly vector among studied population. Moreover, L. tropica was identified in different kinds of animal, suggesting potential important role of animal in the transmission of CL. These findings indicated that there is an urgent need for effective preventive and control measures to protect these vulnerable populations from this devastating disease.

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