부산대학교 도서관

Background: Community presence of loiasis must be determined before mass drug administration programmes for lymphatic filariasis and onchocerciasis can be implemented. However, taking human blood samples for loiasis surveillance is invasive and operationally challenging. A xenosurveillance approach based on the molecular screening of mosquitoes and their excreta/feces (E/F) for Loa loa DNA may provide a non-invasive method for detecting the community presence of loiasis. Methods: We collected 770 wild mosquitoes during a pilot study in a known loiasis transmission area in Mbalmayo, Cameroon. Of these, 376 were preserved immediately while 394 were kept in pools to collect 36-hour E/F samples before processing. Carcasses and E/F were screened for L. loa DNA. To demonstrate this method's potential for integrated disease surveillance, the samples were further tested for Wuchereria bancrofti, Mansonella perstans, and Plasmodium falciparum. Results: Despite limited sample numbers, L. loa DNA was detected in eight immediately-stored mosquitoes (2.13%; 95% CI 1.08 to 4.14), one carcass stored after providing E/F (0.25%; 95% CI 0.04 to 1.42), and three E/F samples (estimated prevalence 0.77%; 95% CI 0.15 to 2.23%). M. perstans and P. falciparum DNA were also detected in carcasses and E/F samples, while W. bancrofti DNA was detected in E/F. None of the carcasses positive for filarial worm DNA came from pools that provided a positive E/F sample, supporting the theory that, in incompetent vectors, ingested parasites undergo a rapid, complete expulsion in E/F. Conclusions: Mosquito xenosurveillance may provide a useful tool for the surveillance of loiasis alongside other parasitic diseases. Author summary: Loiasis is a typically-mild filarial worm disease. In contrast, lymphatic filariasis (LF) and onchocerciasis are diseases of significant public health concern. LF and onchocerciasis are primarily controlled by administering chemotherapeutics to entire at-risk human populations. However, individuals with heavy loiasis infections are at risk of severe adverse events when treated with these drugs. Accurate loiasis surveillance is therefore critical to the safe implementation of these programmes. Screening humans to detect parasites in the blood is invasive and expensive at large scale. Recently, however, several studies have demonstrated the potential of collecting wild blood-feeding insects such as mosquitoes and screening them for the presence of human blood-borne parasites. To explore the potential of mosquito screening as a non-invasive tool for loiasis surveillance, we collected mosquitoes in a known loiasis transmission area in Cameroon. We tested the samples for parasites that cause loiasis, and concurrently screened for the parasites that cause malaria, LF and mansonellosis to determine the potential for integrated disease surveillance. The DNA of all four parasites were identified using these methods. The findings suggest mosquito screening may provide a useful tool for the surveillance of loiasis alongside other parasitic diseases. [ABSTRACT FROM AUTHOR]