Simple clinical and laboratory predictors to improve empirical treatment strategies in areas of high scrub typhus and dengue endemicity, central Vietnam.

BACKGROUND: Dengue fever is highly endemic in Vietnam, but scrub typhus-although recognized as an endemic disease-remains underappreciated. These diseases together are likely to account for more than half of the acute undifferentiated fever burden in Vietnam. Scrub typhus (ST) is a bacterial disease requiring antimicrobial treatment, while dengue fever (DF) is of viral etiology and does not. The access to adequate diagnostics and the current understanding of empirical treatment strategies for both illnesses remain limited. In this study we aimed to contribute to the clinical decision process in the management of these two important etiologies of febrile illness in Vietnam. METHODS: Using retrospective data from 221 PCR-confirmed scrub typhus cases and 387 NS1 protein positive dengue fever patients admitted to five hospitals in Khanh Hoa province (central Vietnam), we defined predictive characteristics for both diseases that support simple clinical decision making with potential to inform decision algorithms in future. We developed models to discriminate scrub typhus from dengue fever using multivariable logistic regression (M-LR) and classification and regression trees (CART). Regression trees were developed for the entire data set initially and pruned, based on cross-validation. Regression models were developed in a training data set involving 60% of the total sample and validated in the complementary subsample. Probability cut points for the distinction between scrub typhus and dengue fever were chosen to maximise the sum of sensitivity and specificity. RESULTS: Using M-LR, following seven predictors were identified, that reliably differentiate ST from DF; eschar, regional lymphadenopathy, an occupation in nature, increased days of fever on admission, increased neutrophil count, decreased ratio of neutrophils/lymphocytes, and age over 40. Sensitivity and specificity of predictions based on these seven factors reached 93.7% and 99.5%, respectively. When excluding the "eschar" variable, the values dropped to 76.3% and 92.3%, respectively. The CART model generated one further variable; increased days of fever on admission, when eschar was included, the sensitivity and specificity was 95% and 96.9%, respectively. The model without eschar involved the following six variables; regional lymphadenopathy, increased days of fever on admission, increased neutrophil count, increased lymphocyte count, platelet count ≥ 47 G/L and age over 28 years as predictors of ST and provided a sensitivity of 77.4% and a specificity of 90.7%. CONCLUSIONS: The generated algorithms contribute to differentiating scrub typhus from dengue fever using basic clinical and laboratory parameters, supporting clinical decision making in areas where dengue and scrub typhus are co-endemic in Vietnam.

Ecological and behavioural risk factors of scrub typhus in central Vietnam: a case-control study.

BACKGROUND: The risk factors for scrub typhus in Vietnam remain unknown. Scrub typhus caused by Orientia tsutsugamushi often presents as an undifferentiated febrile illness and remains under appreciated due to the limited availability of diagnostic tests. This tropical rickettsial illness is increasingly recognized as an important cause of non-malaria acute undifferentiated fever in Asia. This study aimed to investigate behavioural and ecological related risk factors of scrub typhus to prevent this potentially life-threatening disease in Vietnam. METHODS: We conducted a clinical hospital-based active surveillance study, and a retrospective residence-enrolment date-age-matched case-control study in Khanh Hoa province, Vietnam, from August 2018 to March 2020. Clinical examinations, polymerase chain reaction and enzyme-linked immunosorbent assay IgM tests were applied to define cases and controls. All enrolled participants filled out a questionnaire including demographic socio-economic status, personal behaviors/protective equipment, habitat connections, land use, and possible exposure to the vector. Multivariable conditional logistic regression was used to define the scrub typhus associated risk factors. RESULTS: We identified 44 confirmed cases and matched them with 152 controls. Among cases and controls, the largest age group was the 41-50 years old and males accounted for 61.4% and 42.8%, respectively. There were similarities in demographic characteristics between the two groups, with the exception of occupation. Several factors were significantly associated with acquisition of scrub typhus, including sitting/laying directly on household floor [adjusted OR (aOR) = 4.9, 95% CI: 1.6-15.1, P = 0.006], household with poor sanitation/conditions (aOR = 7.9, 95% CI: 1.9-32.9, P = 0.005), workplace environment with risk (aOR = 3.0, 95% CI: 1.2-7.6, P = 0.020), always observing mice around home (aOR = 3.7, 95% CI: 1.4-9.9, P = 0.008), and use of personal protective equipment in the field (aOR = 0.4, 95% CI: 0.1-1.1, P = 0.076). CONCLUSIONS: Ecological and household hygiene-related factors were more associated with scrub typhus infection, than individual-level exposure activities in the hyper-endemic area. These findings support local education and allow people to protect themselves from scrub typhus, especially in areas with limitations in diagnostic capacity.

Reproductive tract infection and related factors among female migrants working in industrial zones in Vietnam 2013-2014.

We conducted this study to analyze factors related to reproductive tract infections (RTIs) among female migrant workers (FMWs) in four industrial zones across four regions in Vietnam. A analytical cross-sectional study was implemented with FMWs aged between 18 and 49 year old in four industrial zones in Hanoi, Da Nang, Ho Chi Minh (HCM) city and Binh Duong, Vietnam. Stratified sampling was used to select about 6400 married and unmarried FMWs. Cases were identified through self-reporting of female migrants concerning RTIs symtoms experienced in the 1 year prior to the study. Based on multivariate logistic regression results, we suggested that about 32% of FMWs reported having RTIs problems (27.6% in Hanoi, 30.3% in Danang, 36% in HCMC and 32.9% in Binhduong). We also identified different factors related to RTIs among different study sites. Marital status, level of education, social-economic status and numbers of migration were important related factors of RTIs.

mHealth information for migrants: an e-health intervention for internal migrants in Vietnam.

BACKGROUND: Socio-economic development in Vietnam has resulted in increased internal migration particularly among young women seeking employment opportunities in cities. Vietnamese female migrants who enter new environments often encounter the loss or neglect of their right to access sexual and reproductive health services. To address this, a mobile health (mHealth) intervention model was implemented over 12 months (2013-2014) in a factory in the Long Bien industrial zone of Hanoi, Vietnam. METHODS: The intervention provided sexual and reproductive health services for female migrants through text messaging, information booklets accompanied maps, and free counseling via a hotline. To evaluate the impact of the intervention, pre- and post-intervention data were collected to measure changes in women's knowledge and practices related to sexual and reproductive health. Qualitative data in the form of personal interviews were also collected. The sample size for the baseline survey was 411 women, and for the post-intervention survey it was 482 women (the intervention involved an open cohort). The majority of women were unmarried and under the age of 25. RESULTS: Results indicate that there was high uptake of the intervention services and that most women found the services important and useful. In addition, there was evidence that the intervention (1) increased women's knowledge of sexual and reproductive health (e.g., proper use of condoms, identification of high-risk behaviors such as having unprotected sex), and (2) fostered improved practices related to sexual and reproductive health (e.g., increased gynecological check-ups and use of condoms). CONCLUSIONS: The study demonstrated the feasibility of implementing a multi-faceted intervention for migrant women working in an industrial zone in Hanoi, Vietnam as well as its successful uptake and some early positive effects. This can be used to inform future design and implementation of mHealth/eHealth intervention models for migrant and other vulnerable/hard to reach population.