Dengue in Timor-Leste during the COVID-19 phenomenon

Dengue is a significant public health problem in mostly tropical countries, including Timor-Leste. Dengue continues to draw attention from the health sector during the COVID-19 phenomenon. Therefore, the goal of this study is to evaluate the dengue incidence rate in comparison with the COVID-19 cumulative number and associated dengue risk factors, including the fatality rate of dengue infection in each municipality during the COVID-19 phenomenon in Timor-Leste, by applying the data processing program in Geographic Information Systems (GIS). A descriptive study using GIS was performed to provide a spatial-temporal mapping of dengue cases. Secondary data, which were sourced from the Department of Health Statistics Information under the Ministry of Health Timor-Leste, were collected for the period during the COVID-19 outbreak in 2020-2021. These data were grounded at the municipal (province) level. Quantum GIS and Microsoft Excel were used to analyze the data. During the COVID-19 outbreak (2020-2021), dengue spread nationwide. It was found that there was an increase in municipalities with high dengue cases and cumulative COVID-19 numbers. The high number of dengue cases associated with the COVID-19 cumulative number found in municipalities with an urban characteristic and in terms of severity, dengue fever (DF) is most commonly reported with a total of 1,556 cases and is followed by dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Most cases were reported in the months of the monsoon season, such as December, January, and March. Dengue GIS mapping helps understand the disease's presence and dynamic nature over time.

Factors affecting preventive behavior against leptospirosis among the population at risk in Si Sa Ket, Thailand

Leptospirosis is a major public health problem in Si Sa Ket, Thailand. Humans can become infected via direct contact with the urine of infected animal reservoir hosts or by indirect contact with contaminated soil and water in the environment. This study examined the factors affecting preventive behavior against leptospirosis among the population at risk in Si Sa Ket, Thailand. A cross-sectional questionnaire was conducted by a representative population survey using a four-stage stratified random sampling to select 350 respondents aged 18–65 years from the fifth districts with the highest morbidity rate in 2010–2019. Data were analyzed by descriptive statistics and stepwise multiple regression. The majority of the respondents were male (53.40%), aged 46–55 years (31.20%), and agricultural workers (76.00%). Their knowledge (M = 10.78, SD = 1.60), perceived severity (M = 2.91, SD = 0.60), perceived probability (M = 2.98, SD = 0.64), self-efficacy expectations (M = 3.18, SD = 0.63), responses-efficacy expectations (M = 3.16, SD = 0.71), social support (M = 3.19, SD = 0.52), and preventive behavior against leptospirosis (M = 3.29, SD = 0.49) were at moderate level. Significant factors affecting leptospirosis preventive behaviors were history of leptospirosis illness (β = 0.312), social support (β = 0.240), perceived probability (β = 0.238), household members with a history of leptospirosis illness (β = 0.158), perceived severity (β = 0.114), self-efficacy expectations (β = 0.094) and knowledge (β = 0.088) regarding leptospirosis. All of these factors could together predict the preventive behavior against leptospirosis up to 42.8% (Adjusted R² = 0.428). Public health interventions should be strengthening people's perception and awareness regarding leptospirosis and the promotion of preventive health behavior to prevent potential outbreaks.

Current status of helminthiases in Thailand: A cross-sectional, nationwide survey, 2019

Helminthiases are common neglected tropical diseases in Thailand, thus regular surveillance is necessary for their control. During fiscal year 2019, the Thailand Ministry of Public Health carried out a cross-sectional nationwide survey in people of all age groups from the 12 Regional Health Offices in 76 provinces of Thailand. Multi-stage cluster random sampling design was employed to assess the prevalence of helminth infections and certain behavioural risk factors. A total of 16,187 stool samples and demographic data were obtained from the participants. Stool examination was done and parasite eggs/lavae were identified microscopically by experienced technicians. Positive stool samples for Opisthorchis viverrini, hookworms, or Ascaris lumbricoides were further quantified and expressed in eggs per gram feces (EPG). The results revealed an overall prevalence of helminthic infections of 9.79% with over 14 species identified. The highest prevalence was hookworms (4.47%) followed by O. viverrini (2.2%) with mean infection intensities of 222.7 EPG and 120.9, respectively. The majority of the infections were low intensity (97.4% for hookworms and 99.1% for O. viverrini). Similarly for A. lumbricoides, 93.9% of the positive cases were low infections. Two major helminthiases caused by hookworms and O. viverrini were highlighted in this report. While the liver fluke was highly endemic in Northeast Thailand, the hookworms were prevalent in the southmost region of the country. Association with demographic characteristics and risk behaviors of the two parasites were analyzed and presented in this study. Overall, this countrywide survey provides basic information of the current status of helminth infections in Thailand. Moreover, the data clearly indicates a dramatic reduction of O. viverrini prevalence likely due to extensive control activities under the national campaign against the liver fluke over the past five years.

Model-based spatial-temporal mapping of opisthorchiasis in endemic countries of Southeast Asia

Opisthorchiasis is an overlooked danger to Southeast Asia. High-resolution disease risk maps are critical but have not been available for Southeast Asia. Georeferenced disease data and potential influencing factor data were collected through a systematic review of literatures and open-access databases, respectively. Bayesian spatial-temporal joint models were developed to analyze both point- and area-level disease data, within a logit regression in combination of potential influencing factors and spatial-temporal random effects. The model-based risk mapping identified areas of low, moderate, and high prevalence across the study region. Even though the overall population-adjusted estimated prevalence presented a trend down, a total of 12.39 million (95% Bayesian credible intervals [BCI]: 10.10–15.06) people were estimated to be infected with O. viverrini in 2018 in four major endemic countries (i.e., Thailand, Laos, Cambodia, and Vietnam), highlighting the public health importance of the disease in the study region. The high-resolution risk maps provide valuable information for spatial targeting of opisthorchiasis control interventions.

Discovery of Carcinogenic Liver Fluke Metacercariae in Second Intermediate Hosts and Surveillance on Fish-Borne Trematode Metacercariae Infections in Mekong Region of Myanmar

Countries of lower Mekong regions are highly alarmed by the spread of fish-borne trematode infections, i.e., small liver flukes and minute intestinal flukes especially in Thailand, Lao People’s Democratic Republic (Lao PDR), Vietnam, Cambodia and Myanmar. Moreover; the incidence of cholangiocarcinoma has also been increasing in the endemic area of liver fluke infections. Only a few reports have been published concerning the fish-borne trematodes infections in the central region of Myanmar. However; there is still a lack of information regarding the status of trematodes infections in second intermediate hosts in the Mekong region of Myanmar. Therefore, we conducted surveillance on the distribution of trematode metacercariae in small cyprinoid fishes collected from the Mekong region of Myanmar. A total of 689 fishes (12 different species of cyprinoid fishes) have been collected and examined by pepsin digestion methods. We discovered four species of fish-borne trematode metacercariae infections, i.e., carcinogenic liver fluke, Opisthorchis viverrini; minute intestinal flukes, Haplorchis taichui; Haplorchis pumilio and Haplorchoides sp. in Tachileik, the Mekong Region of Myanmar. The outcome of this study could be a useful index for the fish-borne zoonotic trematode epidemiology in the Mekong area. Besides, the results of our study contribute to filling the gap of information necessary for the control and prevention of fish-borne trematode zoonotic infections in the Mekong region.

Risk factors for Opisthorchis viverrini infection in Nakhon Phanom, Thailand, where the infection is highly endemic

Background

Opisthorchiasis caused by Opisthorchis viverrini is a serious health issue in the Mekong basin region, resulting in a high prevalence of cholangiocarcinoma. Nakhon Phanom province had the highest prevalence of O. viverrini infection in Thailand at 60% of the surveyed population in 2009, despite the attempted control of opisthorchiasis for >50 years. Knowing risk factors for O. viverrini infection in Nakhon Phanom may lead to improved control and prevention of opisthorchiasis.

Objectives

To determine risk factors for O. viverrini infection in Nakhon Phanom.

Methods

We conducted a cross-sectional survey in Nakhon Phanom province from February to March 2014. The community was selected using a stratified random sampling method, and then, participants were selected by systematic random sampling. Individuals ≥15 years old were included. Knowledge of O. viverrini infection, and attitudes and practice to avoid it were assessed using a questionnaire. O. viverrini infection was determined by stool examination with a formalin–ether concentration method. Factors associated with the infection were determined using multivariate logistic regression analysis.

Results

Of the 134 participants, 75 (56%) were infected with O. viverrini. In the multivariate logistic regression analysis, 3 independent factors were associated with O. viverrini infection: age ≥ 55 years, odds ratio (OR) adjusted 6.36 (95% confidence interval (CI) 1.28–31.66); consumption of chopped raw-fish salad (koi pla), OR adjusted 28.74 (95% CI 3.59–230.24); and perceived susceptibility, OR adjusted 0.15 (95% CI 0.03–0.74).

Conclusions

Age ≥ 55 years, consuming koi pla, and perceived susceptibility were independently associated with O. viverrini infection in Nakhon Phanom.

Brief communication (Original). National survey of helminthiasis in Thailand

Background: Helminth infections continue to pose serious health problems in Thailand. The infections of greatest concern are opisthorchiasis and hookworm.

Objectives: We evaluated the prevalence of these infections. The Thai Ministry of Health established a national health plan in 1995 to coordinate health plans for the provincial public health sectors.

Methods: A national survey based on probability sampling, interviews, and stool examinations was conducted in 2009 to gather prevalence information of the helminth infections.

Results: We found an overall prevalence of helminthiasis among 15,555 Thai people of 18.1%. The highest prevalence was found in the northeastern regions of Thailand. By comparison with previous surveys conducted over the past 5 decades, the prevalence rates have decreased. However, pockets of high infection remain, particularly in the north and northeast of Thailand.

Conclusions: Targeted intervention by means of educational programs and public health intervention, and continuing surveillance are indicated.

Co-infection with Opisthorchis viverrini and Haplorchis taichui detected by human fecal examination in Chomtong district, Chiang Mai Province, Thailand

Diseases caused by the liver fluke, Opisthorchis viverrini and the minute intestinal fluke, Haplorchis taichui, are clinically important, especially in the Northeast and North regions of Thailand. It is often difficult to distinguish between these trematode species using morphological methods due to the similarity of their eggs and larval stages both in mixed and co-infections. A sensitive, accurate, and specific detection method of these flukes is required for an effective epidemiological control program. This study aimed to determine the prevalence of O. viverrini and H. taichui infections in human feces by using formalin-ether sedimentation and high annealing temperature random amplified polymorphic DNA (HAT-RAPD) PCR methods. Fecal specimens of people living along the Mae Ping River, Chomtong district were examined seasonally for trematode eggs using a compound microscope. Positive cases were analyzed in HAT-RAPD, DNA profiles were compared with adult stages to determine the actual species infected, and specific DNA markers of each fluke were also screened. Our results showed that out of 316 specimens, 62 were positive for fluke eggs which were pre-identified as O. viverrini and H. taichui. In addition, co-infection among these two fluke species was observed from only two specimens. The prevalence of H. taichui infections peaked in the hot-dry (19.62%), gradually decreased in the rainy (18.18%), and cool-dry seasons (14.54%), respectively. O. viverrini was found only in the hot-dry season (6.54%). For molecular studies, 5 arbitrary primers (Operon Technologies, USA) were individually performed in HAT-RAPD-PCR for the generation of polymorphic DNA profiles. The DNA profiles in all 62 positives cases were the same as those of the adult stage which confirmed our identifications. This study demonstrates the mixed infection of O. viverrini and H. taichui and confirms the extended distribution of O. viverrini in Northern Thailand.

Prevalence and risk factors for pinworm infection in the kindergarten of Thammasat University, Thailand

We studied the prevalence and risk factors for pinworm infection in children attending the kindergarten of Thammasat University, Pathum Thani, Thailand, using the Scotch-tape technique. Slides were examined by a standard light microscope; 20% of negative slides were reexamined for quality control. Symptoms and risk factor data were collected using a structured questionnaire. Three hundred thirty children age 3 to 6 years old were sampled (males=159). Sixty-five (19.7%) had symptoms consistent with pinworm infection. No pinworm eggs were detected. Most parents (73%) had a good socioeconomic status and 64% were university graduates. Pinworm infection may be uncommon in urban Thailand.

Prevalence of Haplorchis taichui and Haplorchoides sp. metacercariae in freshwater fish from water reservoirs, Chiang Mai, Thailand

A parasitological investigation on trematode metacercariae was made on 62 freshwater fishes of 13 species in northern Thailand; Cyclocheilichthys apogon, Puntioplites proctozysron, Labiobarbus siamensis, Barbodes gonionotus, Barbodes altus, Henicorhynchus siamensis, Osteochilus hasselti, Notopterus notopterus, Mystacoleucus marginatus, Anabas testudineus, Systomus orphoides, Morulius chrysophykadian, and Hampala macrolepidota. The fish were caught over the summer period (February-May 2007) from 2 Chiang Mai water reservoirs, i.e., the Mae Ngad (UTM 47Q E 503200, 47Q N 2119300) and the Mae Kuang Udomtara (UTM 47Q E 513000, 47Q N 2092600) Reservoirs in Chiang Mai province, Thailand. The prevalence of heterophyid (Haplorchis taichui and Haplorchoides sp.) metacercariae in these fish was 83.9% and 74.2% in the Mae Ngad and Mae Kuang Udomtara Reservoirs, respectively. The highest intensity of heterophyid metacercariae in H. siamensis in the Mae Ngad was 120.4 and that in P. proctozysron in the Mae Kuang Udomtara was 180.0. The fish, A. testudineus, C. apogon, and M. chrysophykadian, were not found to be infected with H. taichui metacercariae. The results show that the freshwater fish in Chiang Mai water reservoirs are heavily infected with H. taichui and Haplorchoides sp. metacercariae.

Human intestinal capillariasis in Thailand

Intestinal capillariasis caused by Capillaria philippinensis appeared first in the Philippines and subsequently in Thailand, Japan, Iran, Egypt and Taiwan; major outbreaks have occurred in the Philippines and Thailand. This article reviews the epidemiology, history and sources of C. philippinensis infection in Thailand. The annual epidemiological surveillance reports indicated that 82 accumulated cases of intestinal capillariasis were found in Thailand from 1994-2006. That made Thailand a Capillaria-prevalent area. Sisaket, in northeast Thailand, was the first province which has reported intestinal capillariasis. Moreover, Buri Ram presented a high prevalence of intestinal capillariasis, totaling 24 cases from 1994-2006. About half of all cases have consumed raw or undercooked fish. However, even if the numbers of the intestinal capillariasis cases in Thailand is reduced, C. philippinensis infection cases are still reported. The improvement of personal hygiene, specifically avoiding consumption of undercooked fish and promoting a health education campaign are required. These strategies may minimize or eliminate C. philippinensis infection in Thailand.

Early stage biliary and intrahepatic migration of Opisthorchis viverrini in the golden hamster

In Thailand, infection with the liver fluke Opisthorchis viverrini is a serious health problem, with over 8.6 million human infections each year. Early stage biliary intrahepatic migration and infection of O. viverrini in the Syrian golden hamster were used to study the growth and development of this fluke. Fifty metacercariae of O. viverrini were introduced into each hamster by gastric intubation. Worms were found to migrate rapidly from the stomach to the gall bladder and hepatic duct, where they remained in relatively constant numbers until the end of week 8. Sexual development of worms was rapid, with full development of the uterus and testes by one and one half weeks and the appearance of eggs in the uterus by the beginning of the third week of infection. Worm growth as indicated by body length had ceased by week 8. Hamsters demonstrated development of a full reproductive cycle with in three to four weeks, and this generation continued until 8 weeks.

Impact of health educational programmes on the prevalence of enterobiasis in schoolchildren in Thailand

Enterobiasis is a worldwide prevalent disease particularly in low income areas. The budget needed for the prevention, treatment and eradication of the disease has thus far frustrated the limited budgets of global public health systems. A study was undertaken to determine if education in addition to medical treatment of enterobiasis could make a difference to the rates of infection. A total of 777 children (399 male and 378 female) from 11 elementary schools in five districts of Samut Prakan Province, Thailand were examined between December 2000 and March 2002. In five of the 11 schools studied, medical treatments were applied, followed by a programme of educating the children in the prevention of infection. Children in the remaining six schools received medical treatment only. The study showed a decrease in infections among children who received supplementary education. This decrease was significant in comparison to the decrease shown among children who received medical treatment only. The study therefore showed that educating high risk individuals played a key role in the prevention of enterobiasis.

A study of ectoparasites of Canis lupus familiaris in Mueang district, Khon Kaen, Thailand

We studied ectoparasites found on Canis lupus familiaris sampled in five areas in Mueang district, Khon Kaen Province, Thailand. The prevalence of fleas and ticks as well as their density were determined in 100 dogs that did not receive treatments. A total number of 458 ectoparasites was found corresponding to two species: 25.8% Ctenocephalides canis and 74.2% Rhipicephalus sanguineus. R. sanguineus was the most abundant species, and Ct. canis was the only flea species found. The stages of R. sanguineus were larvae (5.3%), nymphs (29.1%) and adults (39.1% in male and 26.5% in female). The stages of Ct. canis were larvae (41.5%) and adults (58.5%). Both species were commonly found on domestic dogs in all areas of the study. Ct. canis was not present on domestic dogs in one sub-district. The prevalence rates of tick-harboring domestic dogs was 80% (R. sanguineus), and flea-haboring domestic dogs was 26% (Ct. canis).

Ixodid ticks on domestic animals in Samut Prakan Province, Thailand

The prevalence of tick-harboring domestic animals, tick density, and the species of ticks were studied throughout the year 2000, in Muang Samut Prakan, Bang Phli and Phra Pradaeng districts of Samut Prakan Province. The animals examined were Canis lupus familiaris (450), Bos indicus (cross-bred) (189), Bos taurus (30), Bubalus bubalis (171) and Sus scrofa domestica (450). The total number of collected ticks was 1,491. The pigs did not harbor ticks. The stages of ticks collected were larvae, nymphs and adults. The prevalence rates of tick-harboring were 46% (Canis lupus familiaris), 42.86% (Bos indicus, cross-bred), 33.33% (Bos taurus) and 9.35% (Bubalus bubalis). The tick densities were 2.22 (Bos indicus, cross-bred), 2.16 (Canis lupus familiaris), 1.16 (Bos taurus) and 0.36 (Bubalus bubalis). Only 2 species of ixodid ticks, Boophilus microplus and Rhipicephalus sanguineus, were found. R. sanguineus was the dominant species of tick. The percentage of R. sanguineus was 65.2% and B. microplus was 34.8%. In Muang district, R. sanguineus was the dominant species in C. lupus familiaris; in Bang Phli district, B. microplus was the dominant species in Bos indicus (cross-bred). The density of B. microplus was high in the summer season; the density of R. sanguineus was high in the winter season. The number of ticks depended on the geographic location, animal host and season.

Enterobiasis in primary schools in Bang Khun Thian District, Bangkok, Thailand

A study of enterobiasis and its correlation with various factors that could potentially influence the rate of infection was conducted among 3,621 primary school children (five to ten years old), drawn from sixteen schools in Bang Khun Thian District, Bangkok. Diagnosis was by the transparent tape swab technique, which was used to recover Enterobius vermicularis eggs from the perianal region. The transparent tape swabs were then placed on slides for examination by light microscopy. The average rate of infection for the group was 21.57%. No statistically significant differences were found between the male and female children. The younger children had a higher rate of infection. Subjects from schools located in industrial and metropolitan areas showed slightly higher rates of infection than those from agricultural areas. Data from the questionnaires in the study indicated that factors such as parental socio-economic status (occupational, income and education) and the children's personal hygiene contributed to the varying rates of infection.

Malaria and enterobiasis among Karen Long-neck tribe in Mae Hong Son Province

In Thailand, Mae Hong Son Province is highly endemic for malaria. Knowing this, the local Health Department has introduced a program to educate local residents about the risk factors, in particular the dangers and symptoms of malaria. This study was conducted to evaluate these efforts, by determining the number of malaria infections in a segment of the population, and also by testing for enterobiasis among a group of its children. Two villages in Mae Hong Son Province were chosen for this purpose with a combined population of about 300. Of these, 195 were screened for malaria. Two subjects were diagnosed positive for malaria by microscopy. One of these two villages was chosen to screen for Enterobius vermicularis infection in children as well. Out of 69 stool samples, five (7%) showed infection with E. vermicularis: three with a low number of eggs (1-50), and two with a high number of eggs (>100). Compared with infection rates in similar studies, the results of this study indicate that the Health Department's efforts are meeting with relative success. The low prevalence of infection indicates that the villagers are using the information they have received to help combat infection.

Parasitic infections among Karen in Kanchanaburi Province, western Thailand

The purpose of this study was to determine the rate of intestinal parasitic and malarial infections during a period of low infection among the residents of remote Karen villages in Thailand. Fifty-five males and 64 females, aged 6 months to 70 years, were examined for malaria by thick blood smears using the Giemsa staining technique. Of the 119 subjects, 4 (3.36%) showed positive for malaria with vivax gametocytes. Results suggested that mass screening was not an effective way for diagnosing malaria. Stool samples were examined under a light microscope. The overall intestinal parasitic infection rates were 38.24% in 34 males, and 36.11% in 36 females. These were hookworm (17.14%), Ascaris lumbricoides (7.14%), Trichuris trichiura (1.43%), Strongyloides stercoralis (7.14%), Taenia spp (1.43%), Entamoeba histolytica (1.43%), Entamaeba coli (10.00%) and Giatdia lamblia (1.43%). The highest (55.55%) and lowest (16.66%) rates of infection were observed in age groups 0-5 and over 45, years respectively. In addition, A. lumbricoides and T. trichiura were found more frequently in children, while hookworms was found similarly in every age group. Results showed that the Karen living along the western border of Thailand possessed high rates of intestinal parasitic infections. Strict monitoring and control programs for these parasites should be implemented.

The prevalence of Enterobius vermicularis among primary school students in Samut Prakan Province, Thailand

A prevalence survey of Enterobius vermicularis in primary school students aged 6-10 years in Bang Plee district, Samut Prakarn Province, Thailand was undertaken from January to March 2000. There were 783 subjects, 395 males and 388 females. Diagnosis was done by transparent tape swab technique. It revealed that 1) worms were found in 38.82% of the students, 2) there was a correlation between prevalence of parasite infection and student sex and age and 3) family socio-economic background (income and occupation) had no relationship with the prevalence of the enterobiasis (p < 0.05).

The prevalence of enterobiasis in children attending mobile health clinic of Huachiew Chalermprakiet University

A cross sectional survey of Enterobius vermicularis was carried out in 808 children in the Bangkok metropolis and nearby provinces. This was accomplished in a mobile health clinic from Huachiew Chalermprakiet University provided for communities in the areas during April 1999 to May 2000. Children 5-10 years of age were investigated for infestation of Enterobius vermicularis. Diagnosis was done by means of the transparent tape swab technique to recover eggs in the perianal region for examination under a light microscope. The average infection rate in children was 21.91%. The highest infection rate (38.59%) was found in Ang Thong Province, while the lowest one (11.66%) was found in Chonburi Province. The rate of infection seemed to relate to household environmental factors. The infection rate was significantly higher (p<0.05) in agricultural areas and areas farthest from urban Bangkok. Industrial and urban areas had the lower rates of infection. There was no significant difference (p>0.05) in the incidence of infection between males and females.