Prevalence of hypertension among travelers and stability of blood pressure control during travel: a cross-sectional descriptive study and prospective cohort study

BACKGROUND

Hypertension is a common and important risk factor for cardiovascular disease which is the leading cause of death among the general population and travelers. Data on hypertension among travelers are very limited due to the scarcity of research reports in this specific population. Therefore, this study aimed to determine the prevalence of hypertension among adult travelers and the stability of blood pressure control during international trips using a mobile automated blood pressure device.

METHODS

This was a cross-sectional descriptive study conducted at the Thai travel clinic, Hospital for Tropical Diseases in Bangkok, Thailand. All adult travelers completed a questionnaire which included demographic data, medical history, medication use, trip characteristics and hypertension awareness and knowledge. Standard two time blood pressure measurements were performed at the clinic to detect possible undiagnosed hypertension. Travelers with pre-existing hypertension were also invited to monitor their blood pressure level before and during their trip for a total of 14 days by using an automated blood pressure device and reporting the readings back to the study team.

RESULT

During July and October 2022, a total of 1,359 adult travelers visited the Thai Travel Clinic before their international trip. The overall prevalence of hypertension was 28.8%, including those with pre-existing hypertension (6.7%) and those with newly diagnosed hypertension (22.2%). Travelers with newly diagnosed hypertension were significantly younger than travelers with pre-existing hypertension (38.5 years vs. 55.6 years, p < 0.001). Eleven travelers agreed to monitor their blood pressure, Most (90.9%, 10/11) had stable blood pressure control during their trip. One participant had > 10 mmHg higher blood pressure during the trip, however this was not clinically significant. All participants remained well, and acute symptoms secondary to hypertension were not reported.

CONCLUSION

Up to 28.8% of adult travelers seen in pre-travel consultations had hypertension. Most of them were unaware of their blood pressure condition. Vital signs including blood pressure should be evaluated in all pre-travel visits in order to prevent undiagnosed severe hypertension that might lead to hypertensive crisis.

Cardiovascular Manifestation of the BNT162b2 mRNA COVID-19 Vaccine in Adolescents

This study focuses on cardiovascular manifestation, particularly myocarditis and pericarditis events, after BNT162b2 mRNA COVID-19 vaccine injection in Thai adolescents. This prospective cohort study enrolled students aged 13–18 years from two schools, who received the second dose of the BNT162b2 mRNA COVID-19 vaccine. Data including demographics, symptoms, vital signs, ECG, echocardiography, and cardiac enzymes were collected at baseline, Day 3, Day 7, and Day 14 (optional) using case record forms. We enrolled 314 participants; of these, 13 participants were lost to follow-up, leaving 301 participants for analysis. The most common cardiovascular signs and symptoms were tachycardia (7.64%), shortness of breath (6.64%), palpitation (4.32%), chest pain (4.32%), and hypertension (3.99%). One participant could have more than one sign and/or symptom. Seven participants (2.33%) exhibited at least one elevated cardiac biomarker or positive lab assessments. Cardiovascular manifestations were found in 29.24% of patients, ranging from tachycardia or palpitation to myopericarditis. Myopericarditis was confirmed in one patient after vaccination. Two patients had suspected pericarditis and four patients had suspected subclinical myocarditis. In conclusion, Cardiovascular manifestation in adolescents after BNT162b2 mRNA COVID-19 vaccination included tachycardia, palpitation, and myopericarditis. The clinical presentation of myopericarditis after vaccination was usually mild and temporary, with all cases fully recovering within 14 days. Hence, adolescents receiving mRNA vaccines should be monitored for cardiovascular side effects. Clinical Trial Registration: NCT05288231.

PPBP gene as a biomarker for coronary heart disease risk in postmenopausal Thai women

Background

Estrogen is an important ovarian hormone with anti-atherogenic and cardioprotective effects. Postmenopausal women have lower estrogen levels, associated with significantly higher risks of coronary heart disease (CHD) and CHD-related death. Effective biomarkers for the diagnosis, prediction, and treatment of CHD are needed to address this problem and thus reduce the mortality due to CHD in postmenopausal women. We recently reported that the PPBP and DEFA1/DEFA3 genes may be feasible synergistic biomarkers for CHD risk in Thai men with hyperlipidemia. The PPBP gene encodes pro-platelet basic protein (PPBP) from activated platelets, and DEFA1/DEFA3 encodes human neutrophil peptides (HNP) 1-3, mainly produced by activated neutrophils. Both platelets and neutrophils are involved in chronic inflammation during the development of atherogenesis and CHD. This study investigated the potential roles of PPBP and DEFA1/DEFA3 and their proteins as biomarkers for CHD risk in postmenopausal Thai women.

Methods

This cross-sectional study enrolled 90 postmenopausal Thai women, including 12 healthy controls (N), 18 patients with hyperlipidemia (H), and 21 patients diagnosed with CHD. The remaining 39 women were receiving cholesterol-lowering drugs for hyperlipidemia (HD) were excluded from the study. All CHD patients underwent coronary bypass grafting or coronary angioplasty. PPBP and DEFA1/DEFA3 mRNA expression levels in peripheral blood mononuclear cells isolated from heparinized blood were determined by quantitative reverse-transcription polymerase chain reaction. Levels of PPBP and HNP-1-3 proteins in corresponding plasma samples were assessed by enzyme-linked immunosorbent assay. Differences in parameters were compared among groups and correlations between parameters and clinical manifestations were analyzed.

Results

PPBP mRNA and protein levels were significantly increased in the CHD group compared with the N and H groups. In contrast, DEFA1/DEFA3 mRNA and HNP-1-3 protein levels did not differ significantly among the groups. None of the levels were associated with any of the clinical parameters analyzed in this study.

Conclusion

The results indicate that gene and protein expression levels of PPBP, but not DEFA1/DEFA3, and HNP-1-3, may be feasible biomarkers for assessing CHD risk in postmenopausal Thai women with hyperlipidemia.

Cardiac evaluation in adults with dengue virus infection by serial echocardiography

Background

Dengue virus infection (DVI) is a major health problem in many parts of the world. Its manifestations range from asymptomatic infections to severe disease. Although cardiac involvement has been reported in DVI, its incidence has not yet been well established.

Methods

From July 2016 to January 2018, patients hospitalized at the Hospital for Tropical Diseases, Faculty of Tropical Medicine, Mahidol University, Thailand, with dengue virus infection confirmed by positive NS1 or positive dengue immunoglobulin M findings, participated in the study. We characterized the incidence and change in cardiac function by serial echocardiography and levels of troponin-T and creatine kinase-myocardial band (CK-MB) on the day of admission, the day of defervescence, the first day of hypotension (if any), and at 2 week follow-up.

Results

Of the 81 patients evaluated, 6 (7.41%) exhibited elevated biomarker levels. There was no difference in clinical presentation amongst dengue fever, dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS), except for the amount of bleeding. Cardiac involvement was found in 22.2% of patients: 3 (3.70%) had left ventricular systolic dysfunction, 3 (3.70%) had transient diastolic dysfunction, 6 (7.41%) had increased levels of at least one cardiac biomarker (troponin-T or CK-MB), and 6 (7.41%) had small pericardial effusion. Myocarditis was suspected in only two patients (with DHF); thus, myocarditis was uncommon in patients with dengue virus infection. Three patients developed DSS during admission and were transferred to the intensive care unit.

Conclusion

Cardiac involvement in adults with dengue infection was common, ranging from elevated cardiac biomarker to myocarditis. Abnormalities in cardiac function had resolved spontaneously by the day of follow-up, without specific treatment. We found that DHF was a significant risk factor for cardiac involvement. Echocardiography is the investigation of choice for evaluating the haemodynamic status of patients with DVI, especially in severe dengue.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06639-x.

Molecular Characterization of Seasonal Influenza A and B from Hospitalized Patients in Thailand in 2018-2019

Influenza viruses continue to be a major public health threat due to the possible emergence of more virulent influenza virus strains resulting from dynamic changes in virus adaptability, consequent of functional mutations and antigenic drift in surface proteins, especially hemagglutinin (HA) and neuraminidase (NA). In this study, we describe the genetic and evolutionary characteristics of H1N1, H3N2, and influenza B strains detected in severe cases of seasonal influenza in Thailand from 2018 to 2019. We genetically characterized seven A/H1N1 isolates, seven A/H3N2 isolates, and six influenza B isolates. Five of the seven A/H1N1 viruses were found to belong to clade 6B.1 and were antigenically similar to A/Switzerland/3330/2017 (H1N1), whereas two isolates belonged to clade 6B.1A1 and clustered with A/Brisbane/02/2018 (H1N1). Interestingly, we observed additional mutations at antigenic sites (S91R, S181T, T202I) as well as a unique mutation at a receptor binding site (S200P). Three-dimensional (3D) protein structure analysis of hemagglutinin protein reveals that this unique mutation may lead to the altered binding of the HA protein to a sialic acid receptor. A/H3N2 isolates were found to belong to clade 3C.2a2 and 3C.2a1b, clustering with A/Switzerland/8060/2017 (H3N2) and A/South Australia/34/2019 (H3N2), respectively. Amino acid sequence analysis revealed 10 mutations at antigenic sites including T144A/I, T151K, Q213R, S214P, T176K, D69N, Q277R, N137K, N187K, and E78K/G. All influenza B isolates in this study belong to the Victoria lineage. Five out of six isolates belong to clade 1A3-DEL, which relate closely to B/Washington/02/2009, with one isolate lacking the three amino acid deletion on the HA segment at position K162, N163, and D164. In comparison to the B/Colorado/06/2017, which is the representative of influenza B Victoria lineage vaccine strain, these substitutions include G129D, G133R, K136E, and V180R for HA protein. Importantly, the susceptibility to oseltamivir of influenza B isolates, but not A/H1N1 and A/H3N2 isolates, were reduced as assessed by the phenotypic assay. This study demonstrates the importance of monitoring genetic variation in influenza viruses regarding how acquired mutations could be associated with an improved adaptability for efficient transmission.

Etiology, Clinical Course, and Outcomes of Pneumonia in the Elderly: A Retrospective and Prospective Cohort Study in Thailand

Pneumonia is a leading cause of hospitalization and death among elderly adults. We performed a retrospective and prospective observational study to describe the etiology, clinical course, and outcomes of pneumonia for patients 60 years and older in Thailand. We enrolled 490 patients; 440 patients were included in the retrospective study and 50 patients were included in the prospective study. The CURB-65 score and a modified SMART-COP score (SMART-CO score) were used to assess disease severity. The median patient age was 80 years (interquartile range, 70-87 years); 51.2% were men. Klebsiella pneumoniae (20.4%) and Pseudomonas aeruginosa (15.5%) were the most common causative agents of pneumonia. A significant minority (23%) of patients were admitted to the intensive care unit (ICU), and mortality among this subset of patients was 45%. Most patients (80.8%) survived and were discharged from the hospital. The median duration of hospitalization was 8 days (interquartile range, 4-16 days). In contrast, 17.6% of patients died while undergoing care and 30-day mortality was 14%. Factors significantly associated with mortality were advanced age (P = 0.004), male sex (P = 0.005), multiple bacterial infections (P = 0.007; relative risk [RR], 1.88; 95% confidence interval [CI], 1.19-2.79), infection with multi-drug-resistant/extended-spectrum B-lactamase-producing organisms (P < 0.001; RR, 2.82; 95% CI, 1.83-4.85), ICU admission (P < 0.001; RR, 1.8; 95% CI, 1.4-2.3), and complications of pneumonia (P < 0.001; RR, 2.5; 95% CI, 1.8-3.4). Patients with higher SMART-CO and CURB-65 scores had higher rates of ICU admission and higher 30-day mortality rates (P < 0.001). These results emphasize the importance of Gram-negative bacteria, particularly K. pneumoniae and P. aeruginosa, as major causes of pneumonia among the elderly. Streptococcus pneumoniae is a common cause of pneumonia among elderly individuals worldwide. The SMART-COP and CURB-65 scores were developed to assess pneumonia severity and predict mortality of young adults with pneumonia. Few studies have examined the appropriateness of these scores for elderly patients with multiple comorbidities. A limited number of studies have used modified versions of these scores among elderly individuals. We found that Gram-negative bacteria has a major role in the etiology of pneumonia among elderly individuals in Southeast Asia. A significant proportion of elderly individuals with low CURB-65 scores were admitted to the hospital, indicating that hospital admission may reflect fragility among elderly individuals with low CURB-65 scores. The modified SMART-COP score (SMART-CO score) sufficiently predicted intensive care unit admission and the need for intensive vasopressor or respiratory support. A SMART-CO score ≥ 7 accurately predicted 30-day mortality.

Incidence of health problems in travelers to Southeast Asia: a prospective cohort study

BACKGROUND

There are few studies of the incidence of health problems among travelers to Southeast Asia. The current study sought to determine the incidence of self-reported health problems among travelers visiting the region.

METHODS

A prospective questionnaire-based study was conducted among travelers from high-income countries who visited Southeast Asia. Participants were enrolled at time of their pre-travel visit at Mahidol University, Bangkok, Thailand. Travelers were prospectively followed by self-administered questionnaires 2 weeks after arrival, upon return to their home country and 2 weeks after return.

RESULTS

During January 2018-February 2019, 359 travelers were enrolled in Bangkok, Thailand, and the first questionnaire was administered. Follow-up questionnaires were returned by 191, 96 and 64 participants 2 weeks later, at the end of the trip and 2 weeks after return, respectively. A total of 6094 travel days were included in the final analysis. The incidence of acute diarrhea per month per 1000 travelers was 217 [95% confidence interval (CI), 189-248] episodes; skin problems, 197 (95% CI, 170-227); respiratory symptoms, 133 (95% CI, 111-158); fever, 49 (95% CI, 36-65); and potential rabies exposure, 34 (95% CI, 24-48). The incidence of acute diarrhea episodes per month per 1000 travelers was significantly higher during the first 2 weeks of travel compared with subsequent weeks of travel: 325 (95% CI, 291-362) vs 132 (95% CI, 110-1157) (P < 0.05). The incidence of outpatient visits and hospitalizations per month per 1000 travelers was 49 (95% CI, 36-65) and 5 (95% CI, 2-10), respectively.

CONCLUSIONS

In this prospective cohort study we observed substantial burden of acute diarrhea and skin and respiratory symptoms among travelers to Southeast Asia. The higher incidence of diarrhea in the first 2 weeks of travel should be further investigated.

ConcomitantPlasmodium vivaxmalaria and murine typhus infection with pulmonary involvement

We report a case of Plasmodium vivax and murine typhus coinfection in a 30-year-old woman who presented with intermittent, high-grade fever. Her peripheral blood smear showed ring-form trophozoites of P. vivax, with an initial murine typhus serological test being negative. Although the P. vivax infection was successfully treated, she still had intermittent, high-grade fever, developed dyspnoea and bilateral interstitial pneumonitis shown in the chest X-ray. Thus, coinfection was suspected, and empirical antibiotics were given. The second serological test confirmed the concomitant murine typhus infection, and antibiotics treatment were successful with the complete recovery. This case emphasises that an initial negative murine typhus serological test does not necessarily rule out the presence of the disease. A follow-up murine typhus serological or molecular test within 1–2 weeks is therefore recommended.

Hepatitis B vaccination for international travelers to Asia

There is a wide range in prevalence of hepatitis B virus (HBV) infection and HBV immunization programs between different regions. Hepatitis B is a vaccine preventable disease yet is still endemic in the majority of countries in Asia. Despite the decreasing global prevalence of chronic HBV infection, there is still considerable risk of HBV infection among international travelers to high endemic areas. Numbers of international travelers are expected to increase year by year; thus immunization among this cohort is a crucial preventive measure. Among international travelers to Asia, HBV immunization should be recommended for those without previous HBV vaccination who plan to travel to countries with intermediate to high prevalence of HBV, and especially for those individuals at greater risk of HBV infection; including travelers engaging in casual sex, getting a tattoo or piercing, and those having dental surgery or other medical procedures. Longer duration of travel is also associated with a greater risk of HBV infection. Travelers from low HBV prevalence countries, especially those born before implementation of universal HBV vaccination, might benefit from HBV vaccination during long-term traveling to HBV intermediate to high endemic country.

Health problems and health care seeking behavior among adult backpackers while traveling in Thailand

Background

Health problems among travelers in developing countries are not uncommon. Little is known about the occurrence of health problems and their impacts among backpackers in Thailand. The objective of this study was to assess the health problems and the health seeking behavior among adult backpackers who visited Thailand.

Methods

This was a cross-sectional questionnaire-based study. Data were collected from foreign adult backpackers in Khao San Road, Bangkok. They were asked about their demographic data, health problems (if any), and health-care seeking behavior if they became ill.

Results

During May to July 2015, 420 backpackers were enrolled in this study. Of these, 51.4 % were male with a median age of 26.4 years. Up to 66.9 % were of European origin, while 17.4 % were North American. Fifty-eight percent sought pre-travel consultation before traveling. In this study, 10.2 % (43/420) of the participants reported at least health problem during travel. Most of them (79.1 %) had single episode of illness. Of this, diarrhea was the most common health problem (30.4 %), followed by abdominal pain (14.3 %), skin problems (8.9 %), respiratory problems (8.9 %), accident-associated injury (7.1 %), and febrile illness (7.1 %). One third of backpackers with health problems spontaneously recovered without any treatment, while nearly a quarter treated themselves with standby medication, and one in five had to buy over the counter medication. Just over 9 % of backpackers with a health problem sought medical care at a hospital. Among travellers with health problems, 72.1 % reported that their health problems did not significantly impact to their trip, while 23.3 % had to delay or postpone their trip for at least 1 day, and 4.7 % had to cancel some trip and/or activity. Longer duration of stay was significantly related to higher occurrence of health problems while traveling.

Conclusions

Approximately 10 % of adult backpackers experienced some health problems during their trip in Thailand. Although most of their health problems were mild, up to 22 % of backpackers with health problems need to seek medical care either in a clinic or in a hospital.

Knowledge, attitudes, and practices among foreign backpackers toward malaria risk in southeast Asia

BACKGROUND

Malaria is still prevalent in Southeast Asia where large numbers of backpackers visit each year. This study aimed to assess the knowledge, attitude, and practices among foreign backpackers toward malaria risk in Southeast Asia.

METHODS

Questionnaires were administered to foreign backpackers in Bangkok, Thailand. They were asked about their general background, their attitude to malaria risk, and their preventive measures against malaria. Their knowledge about malaria was assessed by 10 true-false questions in the questionnaires.

RESULTS

In total, 434 questionnaires were evaluated. Fifty-five percent of travelers were male and the median age was 28 years. The main reason for travel was tourism (91%). Almost all travelers (94%) were aware of the risk of malaria. Twenty-two percent of them would take antimalarial prophylaxis and 33% would use measures against mosquito bite, but nearly 40% had "no prevention" at all. Mean knowledge score was only 5.52 of 10. Most backpackers (92%) knew that malaria is a serious disease and sometime fatal and 74% knew that some travelers could develop malaria after they return. However, up to 35% believed that eating contaminated food could lead to malaria infection. And 49% believed that malaria could be 100% prevented by chemoprophylaxis. In backpackers, who had traveled in the forest (n = 65), only 54% used insect repellent regularly. Among those who had taken antimalarial prophylaxis, nearly 30% had stopped the medication prematurely.

CONCLUSIONS

Although most backpackers perceive the risk of malaria in Southeast Asia, they have some misunderstandings about malaria and tend to comply poorly with mosquito bite prevention and chemoprophylactic strategies.