Epidemiology of forest malaria in Central Vietnam: the hidden parasite reservoir

BackgroundAfter successfully reducing the malaria burden to pre-elimination levels over the past two decades, the national malaria programme in Vietnam has recently switched from control to elimination. However, in forested areas of Central Vietnam malaria elimination is likely to be jeopardized by the high occurrence of asymptomatic and submicroscopic infections as shown by previous reports. This paper presents the results of a malaria survey carried out in a remote forested area of Central Vietnam where we evaluated malaria prevalence and risk factors for infection.MethodsAfter a full census (four study villages?=?1,810 inhabitants), the study population was screened for malaria infections by standard microscopy and, if needed, treated according to national guidelines. An additional blood sample on filter paper was also taken in a random sample of the population for later polymerase chain reaction (PCR) and more accurate estimation of the actual burden of malaria infections. The risk factor analysis for malaria infections was done using survey multivariate logistic regression as well as the classification and regression tree method (CART).ResultsA total of 1,450 individuals were screened. Malaria prevalence by microscopy was 7.8% (ranging from 3.9 to 10.9% across villages) mostly Plasmodium falciparum (81.4%) or Plasmodium vivax (17.7%) mono-infections; a large majority (69.9%) was asymptomatic. By PCR, the prevalence was estimated at 22.6% (ranging from 16.4 to 42.5%) with a higher proportion of P. vivax mono-infections (43.2%). The proportion of sub-patent infections increased with increasing age and with decreasing prevalence across villages. The main risk factors were young age, village, house structure, and absence of bed net.ConclusionThis study confirmed that in Central Vietnam a substantial part of the human malaria reservoir is hidden. Additional studies are urgently needed to assess the contribution of this hidden reservoir to the maintenance of malaria transmission. Such evidence will be crucial for guiding elimination strategies

Blood pressure screening results from May Measurement Month 2019 in Vietnam

Elevated blood pressure (BP) is a growing burden worldwide, leading to over 10 million deaths each year. May Measurement Month (MMM) is a global initiative to raise awareness of high BP and act as a temporary solution to the lack of screening programmes worldwide. We aimed to screen for hypertension and cardiovascular risk factors in people aged ≥18 years in the community, thereby defining the proportion of subjects with elevated BP and assess the awareness and the effectiveness of its treatment. An opportunistic cross-sectional survey of volunteers aged ≥18 years was carried out in May 2019. Blood pressure measurement, the definition of hypertension and statistical analysis followed the standard MMM protocol. From May 2019 to June 2019, through 10 cities/provinces in Vietnam, 25 887 individuals with mean age 48.7 (SD ±17.7) years were screened. After multiple imputations, 8758 (33.8%) had hypertension. Of individuals not receiving antihypertensive medication, 3025 (15.0%) were hypertensive. Of individuals receiving antihypertensive medication, 2800 (48.8%) had uncontrolled BP. Raised BP [systolic BP (SBP) ≥140 mmHg and/or diastolic BP (DBP) ≥90 mmHg] was also associated with additional risk factors including smoking, alcohol intake, previous hypertension in pregnancy, and obesity. May Measurement Month 2019 was the most extensive BP screening campaign ever undertaken in Vietnam. Undiagnosed and uncontrolled hypertension in Vietnam remains a substantial health problem. Local campaigns applying standardized methods such as MMM 2019 will be beneficial to screen for the significant number of individuals with raised BP and increase the awareness of hypertension