METHODS: A representative sample of 1747 adolescents (13-14 years) was randomly selected from 6 schools in a south part of Malaysia. Respondents were asked to fill consent form, and questionnaires including Depression Anxiety and Stress Scale-21 and Physical Activity Questionnaire for Adolescents.
RESULTS: Majority of respondents (71.9%) was Malay and more than half of the adolescents had low physical activity. About 40% had depression symptoms, followed by anxiety symptoms (65.9%) and stress symptoms (38.5%). Level of physical activity was significantly associated with gender, anxiety and stress (P<0.001). There were no associations with race, religion and depression symptom.
CONCLUSIONS: This study provides some evidence among school-going adolescents related to anxiety and stress symptoms and low physical activities. Further studies are needed to show the protection effects of higher physical activity for depression, anxiety and stress symptoms in adolescents.
METHODOLOGY/PRINCIPAL FINDINGS: We assessed oral susceptibility of Malaysian Ae. aegypti and Ae. albopictus by real-time PCR to an Australian RRV strain SW2089. Replication kinetics in midgut, head and saliva were determined at 3 and 10 days post-infection (dpi). With a 3 log10 PFU/ml blood meal, infection rate was higher in Ae. albopictus (60%) than Ae. aegypti (15%; p<0.05). Despite similar infection rates at 5 and 7 log10 PFU/ml blood meals, Ae. albopictus had significantly higher viral loads and required a significantly lower median oral infectious dose (2.7 log10 PFU/ml) than Ae. aegypti (4.2 log10 PFU/ml). Ae. albopictus showed higher vector competence, with higher viral loads in heads and saliva, and higher transmission rate (RRV present in saliva) of 100% at 10 dpi, than Ae. aegypti (41%). Ae. aegypti demonstrated greater barriers at either midgut escape or salivary gland infection, and salivary gland escape. We then assessed seropositivity against RRV among 240 Kuala Lumpur inpatients using plaque reduction neutralization, and found a low rate of 0.8%.
CONCLUSIONS/SIGNIFICANCE: Both Ae. aegypti and Ae. albopictus are susceptible to RRV, but Ae. albopictus displays greater vector competence. Extensive travel links with Australia, abundant Aedes vectors, and low population immunity places Kuala Lumpur, Malaysia at risk of an imported RRV outbreak. Surveillance and increased diagnostic awareness and capacity are imperative to prevent establishment of new arboviruses in Malaysia.