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Background The zoonotic malaria parasite Plasmodium knowlesi has emerged across Southeast Asia and is now the main cause of malaria in humans in Malaysia. A critical priority for P. knowlesi surveillance and control is understanding whether transmission is entirely zoonotic or is also occurring through human-mosquito-human transmission. Methods A systematic literature review was performed to evaluate existing evidence which refutes or supports the occurrence of sustained human-mosquito-human transmission of P. knowlesi. Possible evidence categories and study types which would support or refute non-zoonotic transmission were identified and ranked. A literature search was conducted on Medline, EMBASE and Web of Science using a broad search strategy to identify any possible published literature. Results were synthesized using the Synthesis Without Meta-analysis (SWiM) framework, using vote counting to combine the evidence within specific categories. Results Of an initial 7,299 studies screened, 131 studies were included within this review: 87 studies of P. knowlesi prevalence in humans, 14 studies in non-human primates, 13 studies in mosquitoes, and 29 studies with direct evidence refuting or supporting non-zoonotic transmission. Overall, the evidence showed that human-mosquito-human transmission is biologically possible, but there is limited evidence of widespread occurrence in endemic areas. Specific areas of research were identified that require further attention, notably quantitative analyses of potential transmission dynamics, epidemiological and entomological surveys, and ecological studies into the sylvatic cycle of the disease. Conclusion There are key questions about P. knowlesi that remain within the areas of research that require more attention. These questions have significant implications for malaria elimination and eradication programs. This paper considers limited but varied research and provides a methodological framework for assessing the likelihood of different transmission patterns for emerging zoonotic diseases.

Lassa fever virus (LASV) is the causative agent of Lassa fever, a disease endemic in West Africa. Exploring the relationships between environmental factors and LASV transmission across ecologically diverse regions can provide crucial information for the design of appropriate interventions and disease monitoring. We investigated LASV exposure in 2 ecologically diverse regions of Guinea. Our results showed that exposure to LASV was heterogenous between and within sites. LASV IgG seropositivity was 11.9% (95% CI 9.7%–14.5%) in a coastal study site in Basse-Guinée, but it was 59.6% (95% CI 55.5%–63.5%) in a forested study site located in Guinée Forestière. Seropositivity increased with age in the coastal site. We also found significant associations between exposure risk for LASV and landscape fragmentation in coastal and forested regions. Our study highlights the potential link between environmental change and LASV emergence and the urgent need for research on land management practices that reduce disease risks.

Nonsuicidal self-injury (NSSI) in youth is a major public health concern. A retrospective chart review was conducted within a hospital system to examine (a) youth self-reports of reasons for engaging in NSSI and (b) additional contextual circumstances that may contribute to youth NSSI. Detailed history, physical examination, and treatment/discharge data were extracted by thoroughly reviewing all electronic documents in each medical record. The final sample (N = 135) were predominantly female (71.1%), and well over half (63.8%) reported Medicaid or uninsured status. Qualitative content analysis of youth self-reports and hospital progress notes showed that NSSI served as an emotional and functional coping mechanism. Five primary themes characterized the contextual influences on youth engaging in NSSI: (1) Personal Emotions, (2) Trauma, (3) Relationship Quality, (4) Sense of Loss, and (5) Risk Behaviors. Practical clinical practice suggestions for working with youth are discussed using these themes as a template for assessing risk and protective factors.

Lassa fever virus (LASV) is the causative agent of Lassa fever, a disease endemic in West Africa. Exploring the relationships between environmental factors and LASV transmission across ecologically diverse regions can provide crucial information for the design of appropriate interventions and disease monitoring. We measured LASV-specific IgG seropositivity in 1286 sera collected in Coastal and Forested Guinea. Our results showed that exposure to LASV was heterogenous between the sites. The LASV IgG seropositivity was 11.9% (95% CI 9.7-14.5) in Coastal site, while it was 59.6% (95% CI 55.5-63.5) in Forested region. Interestingly, exposure was significantly associated with age, with seropositivity increasing with age in the Coastal site. Finally, we also found significant associations between exposure risk to LASV and landscape fragmentation in Coastal and Forested regions. This study may help to define the regions with an increased exposure risk to LASV where a close surveillance of LASV circulation is needed.