The cost of dengue hemorrhagic fever in Thailand.

The economic burden of DHF patients and of the Thai government in providing treatment and prevention and control of dengue hemorrhagic fever were assessed. Patient burden was reported by caretakers who stayed with the patients when they were admitted to three hospitals: Children's Hospital in Bangkok; Suphan Buri Provincial Hospital and Don Chedi Community Hospital, Don Chedi District in Suphan Buri Province. The hospital costs--medicine and laboratory costs--were collected from the treatment forms and the routine service cost was estimated by the staff of the hospitals. Cost of prevention and control were compiled from the budget report of Departments of the Ministry of Public Health and the Ministry of Interior. Based on 184 DHF patients admitted at the three hospitals, the direct patient costs--treatment cost and the costs of travel, food and lodging--was 66.99 US$ and 61.02 US$ per patient for one episode of DHF in Bangkok and Suphan Buri, respectively. The total patient costs--direct patient costs and opportunity costs were 118.29 US$ for a child patient and 161.49 US$ for an adult patient in Bangkok, 102.82 US$ for a child patient and 138.02 US$ for an adult patient in Suphan Buri. The net hospital cost in providing treatment for each DHF patient was 54.6 US$ and 38.65 US$ in Bangkok and Suphan Buri, respectively. The total cost of prevention and control of DHF in Thailand from government agencies in 1994 was 4.8724 million US$. Based on these findings, the whole expenditure of Thailand for DHF in 1994, would be at least 12.596 million US$, of which 54.8% was from the government budget, the rest, 45.2%, was the expenses paid by 51,688 patients and their families. The study concluded that in recording the economic-loss of DHF both the expenditures of the government and also the patient costs--direct and indirect--should be taken into account.

Treatment seeking behavior of DHF patients in Thailand.

A study on treatment seeking behavior of dengue hemorrhagic fever (DHF) patients was made from 184 clinically diagnosed patients in three hospitals: Children's Hospital, Bangkok; Suphan Buri Provincial Hospital, Suphan Buri Province and Don Chedi Community Hospital in the district of Don Chedi, Suphan Buri Province. The information was collected by interviewing the patients' caretakers while they were attending the patients in the hospitals, using a series of closed- and open-ended questions. Based on the first place of treatment, five patterns of treatment seeking behavior were identified, the most common one was using the clinic as the first step. Different patterns of treatment seeking behavior had the impact on the duration of illness, the number of steps in seeking treatment and the direct patient costs. The socio-demographic characteristics of the patient's caretaker that influenced the decision making to take treatment alternatives included the level of education, occupation, residential area and lay symptom assessment. In addition, economic factors: the capability to reimburse the cost of treatment, the family income and the financial sources, were also important for caretakers to take into consideration when making treatment choices.

Comparative horizontal starch gel isoenzyme electrophoresis of Lymnaea (Bullastra) cumingiana (Pulmonata: Lymnaeidae) and related taxa in the Indo-Pacific region.

Foot muscle tissue extracts from six lymnaeid species of the Indo-Pacific region [Lymnaea (Bullastra) cumingiana and L. (Radix) quadrasi from the Philippines, L. (R.) rubiginosa from Indonesia and Thailand, and L. (R.) viridis from Guam and Hong Kong] were subjected to horizontal starch gel isoenzyme electrophoresis and assayed for seven isoenzymes (AcP, AlP, CA, EST, LAP, CAT and GOT) to elucidate their taxonomic relationships. L. cumingiana exhibited banding patterns for EST, LAP and CAT uniquely different from the rest, thus supporting the hypothesis that it is a distinct species. Zymogram patterns for AlP, CA, EST and LAP attest to the close affinity between L. quadrasi and L. rubiginosa (Indonesia and Thailand). Minor differences suggest a closer relationship between the two geographical strains of L. rubiginosa than with L. quadrasi, lending support to the hypothesis that L. quadrasi is inseparable as a race or variety from the typical L. swinhoei Adams, which in turn is but a race of L. auricularia, which also encompasses L. rubiginosa. The two geographical strains of L. viridis from Guam and Hong Kong showed the greatest consistency with regards to similarity and congruence in banding patterns. Non-specific esterases (EST) were the most useful in distinguishing the six species from each other.

Ecological observations on Lymnaea (Bullastra) cumingiana.

Field surveys conducted at Echague, Isabela and San Pablo, Laguna revealed that Lymnaea (Bullastra) cumingiana, the natural second snail intermediate host of Echinostoma malayanum in the Philippines, exhibits a moderate degree of diversity in its choice of habitats. Rice fields of all stages of development, stagnant shallow streams and springs are the main areas where the snail can be collected from at Echague, Isabela. However, they were absent in rice fields that had been extensively sprayed with molluscicides to control the "golden apple snail" (Ampullarius canaliculatus). In contrast, they were also very abundant in the highly eutrophic waters of Sampaloc lake, San Pablo, Laguna. L. cumingiana co-exists with various species of insects, snails, fish and plants in these habitats. Information on ecological characteristics affecting its distribution will be useful for those who wish to collect and study this species in the future.

Comparative shell morphology of Lymnaea (Bullastra) cumingiana (Pulmonata: Lymnaeidae) and related taxa in the Indo-Pacific region.

Comparative shell morphology using both quantitative and qualitative parameters was employed to investigate the taxonomic relationship between the endemic Philippine species, Lymnaea (Bullastra) cumingiana and five other lymnaeid "species" in the Indo-Pacific region, namely: L. (Radix) quadrasi (Philippines). L. (Radix) rubiginosa (Indonesia), L. (Radix) rubiginosa (Thailand), L. (Radix) viridis (Guam) and L. (Radix) viridis (Hong Kong). Fifty randomly chosen adult specimens of each species were studied and compared, although only field-collected specimens were studied for the first four groups and laboratory-raised specimens for the last two group. Results strongly suggested that L. cumingiana is a distinct species among the rest. L. quadrasi, L. rubiginosa (Indonesia) and L. rubiginosa (Thailand) exhibited great affinity towards each other. Likewise, the two geographical isolates of L. viridis were practically identical to each other except for some minor size differences.

Comparative radular morphology of Lymnaea (Bullastra) cumingiana (Pulmonata: Lymnaeidae) and related taxa in the Indo-Pacific region.

The radular morphology of Lymnaea (Bullastra) cumingiana was compared to that of five other Indo-Pacific lymnaeid "species", namely: L. (Radix) quadrasi (Philippines), L. (R.) rubiginosa (Indonesia and Thailand) and L. (R.) viridix (Guam and Hong Kong) in order to investigate the taxonomic relationship among the six species. Although all six species uniformly exhibited a unicuspid, slightly asymmetrical central (rachidian) tooth and tricuspid laterals, interesting differences were noted among the outer marginals. These were observed to be uniquely bicuspid in L. cumingiana, predominantly tricuspid in L. quadrasi, tetracuspid in L. rubiginosa (Indonesia and Thailand) and multicuspid in L. viridis (Guam and Hong Kong). Thus, the results support the hypotheses that L. cumingiana is a unique species compared to the rest, that L. quadrasi is closely related to L. rubiginosa (Indonesia and Thailand) and that the two geographical isolates of L. viridis have not diverged. Radular morphology was therefore found to have a limited significance in elucidating the taxonomic relationship between the six groups of lymnaeids studied.

Community participation in the malaria control program in Thailand: a review.

The focus of this paper is on community participation in the Thai Malaria Control Program. Two projects concerned are reviewed. First, the Village Voluntary Malaria Collaborator Program has been established for case detection. Second, the Village Malaria Self-Reliance Project aims at malaria prevention. Both projects have been able to get community participation at a certain level. The success of the projects depend on the community, the structures of the projects and the malaria situation in the communities.

Preliminary estimates of economic impact of liver fluke infection in Thailand and the feasibility of irradiation as a control measure.

Liver fluke infection by Opisthorchis viverrini is the leading cause of food-borne parasitic disease in Thailand. Approximately one third of the population in the northeastern region of the country, ie, 6-7 million, are infected by this parasite through the habit of consuming raw or insufficiently cooked freshwater fish, especially those of cyprinoid family. A recent survey showed that 60% of the work force in the Northeast between the age of 15 and 60 is infected. The estimated wage loss of this population may be approximately Baht 1,620 million (US$65 million) per annum. The estimated direct cost of medical care may be as high as Baht 495 million (US$19.4 million) per annum. Thus, the total direct cost of the infected work force is estimated to be Baht 2115 million (US$84.6 million) per annum. Irradiation of fish flesh infected by metacercaria of O. viverrini has been demonstrated as an effective method of control. A minimum dose of 0.1 kGy is effective without changing physiochemical properties of the fish flesh. This technology, therefore, shows promise as a method to control infection by O. viverrini acquired by the habit of consuming raw freshwater fish in the country. Preliminary economic analyses indicate that the public health benefit from preventing infection with this parasite could outweigh the investment cost of irradiation facilities. Detailed economic feasibility studies should be carried out to demonstrate the practical efficacy and cost-effectiveness of the treatment as a public health intervention measure in the country.

The role of folk healers in the malaria volunteer program in Thailand.

In the Malaria Control Program of Thailand, villagers were recruited as village malaria volunteers to assist and participate in passive case detection at the community level by preparation of blood smears and provision of presumptive treatment to suspected cases. Among these volunteers, there were some folk healers. This study was intended to investigate the role of the folk healer volunteer in the Malaria Control Program in the northern area under the responsibility of the Malaria Zone 1, Region 2 in Fang, Mae Ai and Chiang Dao Districts of Chiang Mai Province. The combination of qualitative and quantitative research methodologies (participant and non-participant observations and structured questionnaires) were used to get information from 246 volunteers, of whom 113 were folk healers. Most of the volunteers were male and more than half were in the age group 30-50 years. Almost all volunteers had completed the compulsory education and farming was their main occupation. Folk healer volunteers were older and had been in the service longer than the non-folk healer volunteers. Both groups of volunteers shared some negative attitudes towards the Malaria Control Program, such as the interference with their occupation and the waste of time. However, the folk healer volunteers had more positive attitudes towards the program in terms of gaining social respect and the willingness to stay on. It was also found that the folk healer volunteers performed their assignment better than the non-folk healer volunteers.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrasonographic study of the biliary system in opisthorchiasis patients after treatment with praziquantel.

Ultrasonographic examination of the liver and biliary system using a portable ultrasound unit was performed in 1987 in 647 opisthorchiasis patients who had been treated with praziquantel during 1981 to 1986. Treatments was repeated annually in those reinfected. The reinfection rate was 53.9% in the first year and gradually declined. Ultrasonographic findings were normal in 80.6% of subjects. The most common abnormal finding was liver enlargement (14.8%), followed by dilatation of the gallbladder (3.5%), sludge formation (2.1%) and thickening of the wall of the gallbladder (1.0%). Gallstones were found in 7 cases (1.0%). Dilatation of intrahepatic bile ducts was detected in one subject (0.1%). The incidence of gallstones in treated patients was similar to that reported in a large necropsy series of the general population. Prospective studies will be needed to further investigation the association between opisthorchiasis, treatment and gallstone formation.

Investigation on immunity induced by Schistosoma spindale against S. mekongi in experimental mice.

An investigation on immunity induced by Schistosoma spindale cercariae (cattle and swamp buffalo schistosome) against S. mekongi (human schistosome) was conducted in Swiss albino mice. The studies comprised the development patterns of homologous immunity of S. spindale and heterologous immunity induced by S. spindale against S. mekongi. The development pattern of homologous immunity was studied in mice with an immunization of 100 S. spindale cercariae. At one week intervals, between 2 to 16 weeks after immunization, they were each challenged with 500 S. spindale cercariae. Significant homologous immunity, as judged by lung recovery assay five days after challenge, occurred from week 5 to week 16 with week 8 giving the highest homologous immunity (68.1% of schistosomular reduction). Using the above information mice, with an eight-week immunization period of 100 S. spindale cercariae, were tested for resistance to heterologous S. mekongi infection. The criteria used to evaluate their immune status was schistosomular lung recovery, daily egg output, worm recovery and tissue egg count. The results showed that mice immunized with S. spindale cercariae could develop heterologous immunity against S. mekongi infection. Manifestation of immunity was demonstrated by significant reduction in mean schistosomular recovery (31.4%), in mean daily egg output per female worm (16.7%), in mean worm recovery (64.2%) and in mean egg deposition in the liver tissue and intestines per female worm (37.05%).

Lung-migration patterns of Schistosoma mekongi and S. spindale in mouse.

Two groups of laboratory-bred Swiss albino mice were used to study the lung-migration patterns of Schistosoma mekongi and S. spindale. The first group was individually infected with 100 S. mekongi cercariae by hair-looping application on shaved abdomen. The latter group was individually exposed to 500 S. spindale cercariae by tail immersion. Each group of these infected mice was then divided into subgroups. The number of schistosomulae was determined using a lung recovery assay starting from the second day after infection and continuing for 15 consecutive days. The results revealed a sharp peak of both S. mekongi and S. spindale on the fifth day post cercarial infection.

Health behavior, treatment-seeking patterns, and cost of treatment for patients visiting malaria clinics in western Thailand.

A clinic-based case-control study was conducted at two malaria clinics in western Thailand in order to investigate social and behavioral factors believed to be associated with malaria occurrence. The finding was that the malaria cases were predominantly male, under age 25 and single. The results showed a significant association for use of mosquito nets, conformance with DDT spraying and residing in forested areas two weeks before occurrence of illness with malaria. Analysis of symptoms revealed fever, headache and chills to be the major noticeable symptoms initiating treatment. Three basic treatment-seeking patterns were observed. The results of this study suggest that particular attention should be given to malaria health education for younger age groups and forest-related people. In addition, attention should also be given to ways of increasing awareness of symptoms, and motivation of people to use malaria clinics for malaria screening and treatment at onset of first symptoms in order to eliminate treatment-seeking at ineffective first sources. Malaria Voluntary Collaborators, Village Health Volunteers and Village Health Communicators have an important role in convincing people in malarious areas to use malaria clinics for malaria screening and treatment when the villagers develop malaria-like symptoms. This would reduce disease transmission and severity by reducing the delay for efficacious treatment and would also reduce the cost of malaria treatment.

Social, behavioural, housing factors and their interactive effects associated with malaria occurrence in east Thailand.

This retrospective case-control study was carefully designed to investigate the principal factors that had effects on malaria occurrence. The findings of this study showed that malaria occurs less frequently among persons who have lived in the area for a long period of time, who have obtained education, who have a sizable annual family income. Malaria occurs more frequency among persons who work in or near the forest and persons who move into the forest frequently or occasionally as well as among persons whose houses are in close proximity of vector breeding sites.

Schistosoma japonicum-like infection in Phichit province, northern Thailand: a case report.

A case of human schistosomiasis from Phichit Province is presented. Schistosome eggs were found in the ileo-caecal mass of a 44-year old woman, native of Sak-Lek, Muang District. Histologic pictures revealed an early acute granulomatous lesion which consisted of predominantly eosinophils without multinucleated giant cells and fibrotic change suggesting a recent infection. On the basis of the shape and microscopic appearance of the eggs, they are smaller than those described previously for Schistosoma japonicum, probably those of S. mekongi, a related species. This is the third histologic-confirmed case of schistosomiasis in this locality. Addendum: At the time of the manuscript preparation, another case of schistosomiasis was diagnosed. A 55-year old man who lives entirely in the very close adjacent village to the present case was admitted to the Ramathibodi Hospital, Bangkok with chronic hepatosplenomegaly in January 1986. Amyloidosis was suspected and rectal biopsy revealed schistosome eggs, some contained miracidia with varying degrees of degeneration, some were empty and/or fragmented shells and were surrounded with fibrotic changes and chronic cellular infiltration (Fig. 5). They were identical to those of Schistosoma japonicum. Several fecal examinations, miracidium hatching and COPT yielded negative results. This finding showed significantly that all schistosomiasis cases reported from this locality, except the second one, were in the old age group of 40 and above. Further epidemiologic investigation is in progress to delineate this locality as a potential endemic area for this infection.

Present research on schistosomiasis in Thailand.

The current status of schistosomiasis in Thailand is briefly reviewed. Collaborative research on the Mekong Schistosoma in Thailand and the susceptibilities of the snail intermediate hosts of the schistosomes in Southeast Asia is reported.

Schistosoma mansoni-like infection in Phayao Province, Northern Thailand.

Schistosome ova were found in the serosa of colon mass of a 65-year old Thai woman from Dokkhumtai District, Phayao Province. On the basis of the shape and microscopic appearance of the ova, they probably belonged to those of Schistosoma mansoni complex. In follow-up study, no ova were found by faecal examinations and rectal biopsy. There are evidences suggesting the presence of two distinct mammalian strains in Thailand: Orientobilhorzia harinasutai, a schistosome of water buffalo in Southern region and Tricula bollingi schistosome, a rodent schistosome in Northern region. This case is believed to be the first human schistosome infection with mammalian strain of S. mansoni complex in Thailand.

Migration and disease problems: a study of pattern of migration in an endemic area of malaria in Thailand.

The preliminary results of a study of rural-rural migration in an endemic area of malaria is reported. The study on socio-economic status of migrant workers was made during the post planting season of sugarcane plantation in Tambon Nong Rhee Kanchanaburi Province. Among 9,311 population in four villages of this Tambon, 15.4% were migrants and 45.5% were from the northeast provinces of Thailand. Almost half of the migrant population came to the area for the first time and stayed for six months mostly during the sugarcane cutting season. No significant difference in experience with malaria (as recognized by the people not from blood examination) between the local population and the migrants was observed from the interview. However, the duration of migration seemed to relate with the risk of contracting malaria.