METHODS: An agent-based model (ABM) is a relatively new approach that provides a framework for analyzing the heterogeneity of the interactions, along with biological and environmental factors in such complex systems. The objective of this research is to design and develop an ABM that uses Geospatial Information System (GIS) capabilities, biological behaviors of vectors and reservoir hosts, and an improved Susceptible-Exposed-Infected-Recovered (SEIR) epidemic model to explore the spread of ZCL. Various scenarios were implemented to analyze the future ZCL spreads in different parts of Maraveh Tappeh County, in the northeast region of Golestan Province in northeastern Iran, with alternative socio-ecological conditions.
RESULTS: The results confirmed that the spread of the disease arises principally in the desert, low altitude areas, and riverside population centers. The outcomes also showed that the restricting movement of humans reduces the severity of the transmission. Moreover, the spread of ZCL has a particular temporal pattern, since the most prevalent cases occurred in the fall. The evaluation test also showed the similarity between the results and the reported spatiotemporal trends.
CONCLUSIONS: This study demonstrates the capability and efficiency of ABM to model and predict the spread of ZCL. The results of the presented approach can be considered as a guide for public health management and controlling the vector population .
METHODOLOGY/PRINCIPAL FINDINGS: This study was conducted to determine the molecular characterization of Leishmania species isolated from human cutaneous lesions in Yemen. Dermal scrapes were collected and examined for Leishmania amastigotes using the Giemsa staining technique. Amplification of the ribosomal internal transcribed spacer 1(ITS-1) gene was carried out using nested PCR and subsequent sequencing. The sequences from Leishmania isolates were subjected to phylogenetic analysis using the neighbor-joining and maximum parsimony methods. The trees identified Leishmania tropica from 16 isolates which were represented by two sequence types.
CONCLUSIONS/SIGNIFICANCE: The predominance of the anthroponotic species (i.e. L. tropica) indicates the probability of anthroponotic transmission of cutaneous leishmaniasis in Yemen. These findings will help public health authorities to build an effective control strategy taking into consideration person-to-person transmission as the main dynamic of transmission of CL.
METHODS: Five hundred households in five areas of Shara'b district of Taiz governorate were randomly selected to participate in a quantitative survey. A pretested structured questionnaire was used to collect data on the sociodemographic characteristics of the participants, their knowledge and attitude towards CL and their knowledge on the sand fly vector.
RESULTS: The analysis was conducted on a final sample of 466 individuals (62.7% males and 37.3% females) aged between 18 and 70 years. Among the participants, 21.5% were non-educated while 39.7 and 20.8% had completed secondary school and tertiary education, respectively. Although the participants were aware of CL, about three quarters (77.7%) of them had poor overall knowledge about disease transmission, clinical presentation, treatment, and prevention. Interestingly, approximately half of the participants (49.1%) were able to differentiate sand flies from other flies and mosquitoes. However, only 14.8% of the participants knew about the role of the phlebotomine sand fly in the transmission of CL. Only 36.6% believed that CL can be prevented and 49.6% had a negative attitude towards the disease. Univariate and multivariate analyses showed that age and gender were the significant determinants of knowledge about CL and the sand fly vector among the studied population.
CONCLUSION: A poor level of knowledge about the different epidemiological aspects of CL was found among rural CL-endemic communities in Taiz. This factor, together with the major collapse of the healthcare infrastructure due to the ongoing civil war in Yemen, may be contributing to the continued endemicity of CL in the governorate. It is therefore recommended that health education on CL transmission and prevention should be provided to the targeted communities.