High prevalence and low diversity of chigger infestation in small mammals found in Bangkok Metropolitan parks.

Chiggers are recognized as vectors of scrub typhus disease caused by the bacteria, Orientia tsutsugamushi. The risk of disease exposure is mainly related to chigger bites when humans or animals roam into vector-infested habitats. In big cities, urban public parks could provide areas for the animal-human interface and zoonotic pathogen transmission. The ecology and epidemiology of urban scrub typhus are still poorly understood in Thailand. Small mammals were trapped and examined for chigger infestation in urban public parks across metropolitan Bangkok, Thailand. We found a high prevalence of infestation (76.8%) with surprisingly low diversity. Two chigger species, Leptotrombidium deliense and Ascoschoengastia indica, were identified using morphological characteristics and molecular confirmation. The generalized linear model identified host intrinsic variables (i.e. body mass index) with host density, habitat composition and open field as the extrinsic factors explaining the abundance of chigger infestation. The bacteria O. tsutsugamushi was not detected in chiggers (90 chigger-pooled samples) and animal host tissues (164 spleen samples). However, the existence of chigger vectors calls for the Bangkok Metropolitan Administration and public health authorities to develop a comprehensive scrub typhus monitoring and prevention strategy in the parks and nearby communities.

Co-occurrence of swine cysticercosis due to Taenia solium and Taenia hydatigena in ethnic minority villages at the Thai-Myanmar border.

As part of the international joint projects working towards the control of taeniosis/cysticercosis in Asia Pacific, epidemiological studies on Taenia solium cysticercosis have been carried out in high-incidence populations, such as minority groups in Thailand. To assess the epidemiology of cysticercotic infections in pigs in the hill-tribe minority villages (Karen) in Tak province, Thailand, we conducted serological screening and necropsies. The patterns of antibody response to T. solium antigens were then investigated using immunoblot assays. Of the 188 pig serum samples tested for antibody responses to partially purified low-molecular-weight antigens of T. solium cyst fluid, positive responses were detected in 37 samples (19.7%). Based on these results, 16 pigs (10 seropositive and 6 seronegative) were necropsied for investigation of cysticerci and intestinal parasites. All seropositive pigs were coinfected with both T. solium and Taenia hydatigena cysticerci, except one, which was infected with T. hydatigena alone. Three of the six seronegative pigs were confirmed to be infected with T. hydatigena. Pigs infected with T. solium showed much stronger antibody responses than those infected with T. hydatigena. Our results demonstrate the co-occurrence of two swine cysticercoses due to T. solium and T. hydatigena in the studied areas. This study also reveals the importance of direct confirmation of the presence of cysticerci by necropsy after serological screening. In addition to the prevalence of swine cysticercosis in these endemic areas, our findings also reveal potential implications for the development of serological diagnostic assays for swine cysticercosis.

Distribution of the newly invasive New Guinea flatworm Platydemus manokwari (Platyhelminthes: Geoplanidae) in Thailand and its potential role as a paratenic host carrying Angiostrongylus malaysiensis larvae.

Invasive species constitute one of the most serious threats to biodiversity and ecosystems, and they potentially cause economic problems and impact human health. The globally invasive New Guinea flatworm, Platydemus manokwari (Platyhelminthes: Geoplanidae), has been identified as a threat to terrestrial biodiversity, particularly soil-dwelling native species (e.g. molluscs, annelids and other land planarians), and is listed among 100 of the world's worst invasive alien species. We report here, for the first time, P. manokwari occurrences in many locations throughout Thailand, using voluntary digital public participation from the social network portals associated with the Thailand Biodiversity Conservation Group and collections of living flatworm specimens. Mitochondrial cytochrome c oxidase subunit I (COI) sequences confirmed that all collected flatworms were P. manokwari and placed them in the "world haplotype" clade alongside other previously reported specimens from France, Florida (USA), Puerto Rico, Singapore, French Polynesia, New Caledonia, and the Solomon Islands. In addition, infective stage larvae (L3) of the nematode Angiostrongylus malaysiensis were found in the flatworm specimens, with a 12.4% infection rate (15/121 specimens examined). Platydemus manokwari occurrence in Thailand and its capacity to carry L3 of Angiostrongylus should be of concern to biodiversity conservation and human health practitioners, because this invasive flatworm species may be involved in the life cycle of angiostrongylid worms in Thailand.

Parasitic infections in relation to practices and knowledge in a rural village in Northern Thailand with emphasis on fish-borne trematode infection.

The present study integrates several aspects of a parasitological survey in a rural community village combining community knowledge of parasites, their potential transmission routes and health risk factors. A rural community located in Northern Thailand was surveyed for intestinal parasites, and an overall prevalence of 45.2% for helminths and 4.8% for protozoan infections was identified. Socio-demographic characteristics, customs and perceptions were compiled using individual questionnaires and interviews for participants surveyed for parasitic screening. The results allowed us to determine the knowledge and perception of local people concerning helminthic infection and transmission. Despite the fact that the participants in this community were aware of parasitic transmission routes, their widespread custom of eating raw fish and meat render the reduction of helminthiasis difficult. A detailed study on the infection of fish-borne parasitic trematodes, the most prevalent helminth, allowed us to determine that the distance from a given household to the river is a determinant of infection intensity. Health education activities organised in the local community resulted in a change in perception of risks associated with parasite transmission.

Gastrointestinal helminths and Taenia spp. in parenteral tissues of free-roaming pigs (Sus scrofa indicus) from hilltribe village at the western border of Thailand.

A serological survey of pig cysticercosis was conducted in a hill-tribe village at Thai-Myanmar border, Tak province of Thailand in 2012. Sixteen backyard pigs were examined for pig cysticercosis and gastrointestinal helminth infection. In addition to cysticerci of Taenia solium and Taenia hydatigena found outside the gut, nine other helminth species were found in guts: Echinostoma malayanum, Pseudanoplocephala crawfordi, Ascarops dentata, Physocephalus sexalatus, Gnathostoma doloresi, Ascaris suum, Globocephalus sp., Oesophagostomum dentatum and Bourgelatia diducta. The study presents a report for the first time of adult tapeworm, P. crawfordi infection in pigs from Thailand. For medical importance, E. malayanum, P. crawfordi, G. doloresi and A. suum have been confirmed as potentially zoonotic helminths and pigs may act as one of the reservoir hosts for human helminthiases. Pigs of both gender and all ages appeared to be exposed to the parasites equally and did not show any significant difference to these helminth species in richness and total intensity.

Gastrointestinal helminth fauna of rodents from Cambodia: emphasizing the community ecology of host-parasite associations.

Extensive field surveys of rodents were conducted in Cambodia from 2008 to 2014 to study the diversity and ecology of helminth infection in wild rodent populations. Gastrointestinal helminths were isolated from 14 species of rodents (569 individuals) trapped from different habitats (forest, dry land, rain-fed land and human settlements) in four provinces of Cambodia (Krong Preah Sihanouk, Mondolkiri, Pursat and Steung Treng). The average prevalence of parasitic infection was 58.5% (range, 16.0-64.7%), and 19 helminth taxa were identified in total. Trichostrongylid nematodes were the most prevalent (25.8%), followed by Raillietina sp. (14.1%), Gongylonema neoplasticum (10.7%), Syphacia muris (9.8%) and Hymenolepis diminuta (9.6%). Potential rodent-borne zoonotic helminths were also identified, and the risks of helminthiasis were discussed. The status of helminth infection and species diversity in rodents from settlements were significantly lower than in rodents from forest and peri-domesticated habitats, which indicates that habitat alteration might affect helminth infection and diversity in rodent hosts. Generalized linear models revealed that host attributes (host species and maturity) and environmental factors (habitat and geographical location) were explanatory variables for helminth infection in these rodents. Using network analyses, we showed that the oriental house rat, Rattus tanezumi, was the most central host in the rodent-helminth assemblage, based on the number of helminth taxa it shared with other rodent species. Therefore, R. tanezumi could play an important role in rodent-helminth interactions and helminth transmission to other rodent hosts.

Environmental factors and public health policy associated with human and rodent infection by leptospirosis: a land cover-based study in Nan province, Thailand.

Leptospirosis incidence has increased markedly since 1995 in Thailand, with the eastern and northern parts being the most affected regions, particularly during flooding events. Here, we attempt to overview the evolution of human prevalence during the past decade and identify the environmental factors that correlate with the incidence of leptospirosis and the clinical incidence in humans. We used an extensive survey of Leptospira infection in rodents conducted in 2008 and 2009 and the human incidence of the disease from 2003 to 2012 in 168 villages of two districts of Nan province in Northern Thailand. Using an ad-hoc developed land-use cover implemented in a geographical information system we showed that humans and rodents were not infected in the same environment/habitat in the land-use cover. High village prevalence was observed in open habitat near rivers for the whole decade, or in 2008-2009 mostly in rice fields prone to flooding, whereas infected rodents (2008-2009) were observed in patchy habitat with high forest cover, mostly situated on sloping ground areas. We also investigated the potential effects of public health campaigns conducted after the dramatic flood event of 2006. We showed that, before 2006, human incidence in villages was explained by the population size of the village according to the environmental source of infection of this disease, while as a result of the campaigns, human incidence in villages after 2006 appeared independent of their population size. This study confirms the role of the environment and particularly land use, in the transmission of bacteria, emphasized by the effects of the provincial public health campaigns on the epidemiological pattern of incidence, and questions the role of rodents as reservoirs.

Helminth communities in murid rodents from southern and northern localities in Lao PDR: the role of habitat and season.

The helminth communities of wild murid rodents were investigated in Luang Prabang and Champasak province, Lao PDR. Thirteen species of rodents (404 individuals) were infected by 19 species of parasites (2 trematode, 3 cestode, 14 nematode species). Four of the recorded helminth species (Echinostoma malayanum, Raillietina sp., Hymenolepis diminuta and H. nana) are known to cause potential zoonotic helminthiases of medical importance in the South-East Asian region. Individual helminth infection was significantly higher in the wet season. Habitat significantly influenced individual helminth species richness and individual helminth abudance, with a decrease of individual helminth species richness and individual helminth abundance from forest habitat to agricultural and human settlement habitats. The reduction of helminth diversity and abundance is discussed in relation to the ongoing increase of human influence on habitats in Lao PDR.

Notocotylus loeiensis N. sp. (Trematoda: Notocotylidae) from Rattus losea (Rodentia: Muridae) in Thailand.

Notocotylus loeiensis n. sp. (Trematoda: Notocotylidae) is described from the cecum of the lesser rice field rat (Rattus losea), from Loei Province in Thailand with a prevalence of 9.1% (eight of 88 rats infected). The new species differs from previously described Notocotylus species mainly by the extreme prebifurcal position of the genital pore and the number of ventral papillae. This is the first description at the species level of Notocotylus from mammals in Southeast Asia.

Community awareness and perceptions of health sector preparedness and response to Cyclone Nargis.

Community awareness, preparedness and response to public health emergencies are essential for a successful response to public health emergencies. This study was carried out to determine community awareness and perceptions regarding health sector preparedness and response to Cyclone Nargis in Myanmar. Six focus group discussions were carried out in 3 villages severely affected by Cyclone Nargis. Thematic content analysis was carried out to determine community perceptions. Focus group participants, consisting of community members, community leaders and government personnel, were aware of the cyclone, but were unaware of its intensity and where it would make landfall. There was inadequate knowledge on how to prepare for a cyclone. There was some training on cyclone preparation but coverage was not wide enough. Participants received service and relief from health sector; they had a positive attitude toward health services provided to them. However, 5 out of 6 focus groups stated most villagers were not interested in health education. Only a few participants had some knowledge on how to prepare for a cyclone. Based on these results, there are evident weaknesses on how to prepare for cyclones. Community preparedness is essential to prevent disasters with cyclones, such as with Cyclone Nargis.

Promotion of the health of rural women towards safe motherhood--an intervention project in northeast Thailand.

An intervention project focusing on the health of women in the reproductive age was conducted in three districts of Khon Kaen Province, northeast Thailand between 1991 and 1996. Main emphasis was placed on improving reproductive health, the nutritional status including the iron deficiency anemia (IDA) as well as iodine deficiency disorders (IDD), and the parasitic diseases liver fluke (Opisthorchis viverrini) and hookworm. For implementation a community based Primary Health Care approach was used including the training of health officials in health matters, primary health care workers and villagers as well as enhancing health education and the dissemination of health information. The health delivery system was encouraged to take appropriate actions such as in the treatment of parasitic diseases and the control of IDA and IDD. Monitoring was done on a regular basis. The outcome of the project was assessed by comparing baseline data compiled from a random sample of the target population with the results of the final evaluation. An attempt to compare results obtained from villages within and outside of the project area failed most probably because of spill over effects. A number of important indicators on family planning and mother and child health care improved during the time the project was implemented; this included practising family planning, and participation in antenatal care. Also the proportion of females becoming pregnant for the first time when 20 years or older increased. Child-raising also improved in that almost all females gave colostrum to their babies by this time. Almost 75% of the women breast-fed their children. Improvements occurred in the nutritional status as far as the micronutrients iron and iodine were concerned, however the overall nutritional status of females did not change, but a rather high proportion of females were found to be overnourished. The project failed in reducing abortion and the proportion of females becoming pregnant when they are 18 years old or younger. It was also not possible to improve the usage of postnatal care. As anticipated, the results achieved so far are most suitable in serving as a training ground and providing a favorable example to improve family planning, mother- and child health care, and also the general health of females in the region, particularly in neighboring countries such as Lao PDR, Cambodia and Vietnam.

Managing data for a randomised controlled clinical trial: experience from the WHO Antenatal Care Trial. WHO Antenatal Care Trial Research Group.

The World Health Organisation, in collaboration with four developing countries, is conducting a randomised controlled clinical trial to evaluate a new programme of antenatal care. In a city or region in Argentina, Cuba, Saudi Arabia and Thailand, 53 clinical units were randomly allocated to provide either the new programme or the programme currently in use. This paper describes the organisation of the data management system used to collect the data. Each woman participating in the trial is uniquely identified, and information such as her name, address and expected delivery date is recorded in the trial 'subject number list'. If the clinic belongs to the intervention group, information about the woman's eligibility is recorded on the classification form. Details of the outcome of the pregnancy are indicated on two additional case report forms: the antenatal hospital admission form and the summary form. When forms are completed by the investigators, they are submitted to the country data coordinating centre (CDCC). The CDCCs are responsible for the processing of the country study forms. This includes verification of the batch of forms, data capture into computer files, data verification, data validation, production of query sheets for data problems, maintenance and updating of study master files. All operations on data such as additions or modifications are performed using transaction processing. At monthly intervals, recruitment reports and transaction files are sent to the trial coordinating centre in Geneva. All transaction files are processed to accumulate data on the trial's consolidated master files. A monthly report including number of women recruited in the trial, adverse events reported by the countries, recruitment charts by clinic and analyses on eligible women in the intervention group is prepared and submitted to the data safety and monitoring committee. A workshop was organised in 1995, before the start of the trial, to introduce the data management system to the four participating countries. Annual site visits were made to each CDCC to monitor progress. Additional visits were made when major or critical problems could not be solved by the CDCC. At the closure of data collection, a visit is made to review and assess all data management procedures including form filling, maintenance of registers, computer files, query sheets, data modifications. In addition, final cleaning of the data is performed, and an analysis file is produced for inclusion in the centralised trial analyses and in the country-specific analyses. Based on the experience gained in this trial, the decentralised data management model can be advocated only if CDCCs that will be involved in the trial are already in place with competent and experienced staff. Uniformity of the data management system and of standard operating procedures across countries is also a crucial issue for the effective management of the data collection phase.

Nutritional status and serum lipids of a rural population in Northeast Thailand--an example of health transition.

An investigation was undertaken in Northeast Thailand, a country undergoing rapid health transition, to find out whether there is a likelihood that the nutritional and lipid pattern of an adult population in Northeast Thailand is related to coronary heart disease in the same way as in western countries. In a cross-sectional study, the body mass index (BMI) and the waist-hip ratio as well as the important plasma lipids were determined. The nutritional status and the lipid profile of the predominantly middle-aged population is characterised by a generally favourable nutritional status and lipid concentrations, where the distribution, indicated by the medians, of the relevant variables over the total population is concerned. A rather high proportion of individuals was found to be overnourished and to have high triglyceride levels. Individuals with high triglyceride levels run a risk of developing coronary heart disease only when the LDL-HDL fraction is above 5. Only 3% of the total population investigated had a LDL-HDL ratio above that value. Since hypertriglyceridaemia is also linked to the insulin-resistant syndrome, it is concluded that, if the mortality of coronary heart disease increases in future, then this must be accounted probably more to the after-effects of the insulin-resistant syndrome than to the direct effect of an atherogenic lipid pattern. This view is supported by a high prevalence of impaired glucose tolerance (IGT) and non-insulin dependent diabetes mellitus (NIDDM) in the population under survey. Preventive measures in the area should concentrate among others on reducing overnutrition, especially among women, and increasing physical activity and screening for NIDDM.

Prevalence of abnormal glucose tolerance in Khon Kaen Province and validity of urine stick and fasting blood sugar as screening tools.

Three hundred and fifty-five individuals, 152 males and 203 females, aged between 30 and 74 years, were randomly selected in a two stage selection process from rural communities in three districts of Khon Kaen Province, Northeast Thailand. The prevalence of impaired glucose tolerance (IGT) and non-insulin dependent diabetes mellitus (NIDDM) in the rural area of Northeast Thailand were measured. In addition, the validity of the urine stick and fasting blood sugar as screening tools against the two hours glucose loading test as golden standard were determined. The survey was conducted in July 1995. The glucose loading test was performed on 277 individuals. IGT and NIDDM were classified according to current World Health Organization suggestions. Prevalence rates for IGT were 18.1 per cent and for NIDDM 11.9 per cent. No difference was found between males and females, also when controlled for age. NIDDM prevalence increased with age but IGT rates already were high in the younger age groups. This finding suggests that IGT precedes NIDDM in Thailand. The validity of the urine stick as a screening tool in communities was insufficient, with a sensitivity of less than 20 per cent. When using fasting blood sugar as a screening test, the sensitivity was close to 44 per cent and the specificity 90 per cent. It is concluded that the urine stick is not a useful screening tool and the method of using blood sugar concentrations for screening have to be improved before it can be applied within communities.