A common-source water-borne outbreak of multidrug-resistant typhoid fever in a rural Thai community.

We report an epidemiological investigation of an explosive water-borne outbreak caused by multidrug-resistant (MDR) Salmonella Typhi in a non-endemic community with otherwise good sanitation. Between 31 October and 11 November 1999, 11 cases of typhoid fever occurred in Poppra District, Tak Province. Four cases were children < or = 14 years of age and the remaining 7 were adults 15-24 years old. Hemoculture was performed in 10 of the 11 cases, of whom 5 (50.0%) were positive for Salmonella Typhi. All the isolates were of Vi phage type E14 which was resistant to chloramphenicol, ampicillin, co-trimoxazole, tetracycline, and streptomycin but sensitive to kanamycin, ofloxacin, ciprofloxacin, and cefotaxime. One confirmed case developed intestinal perforation leading to death. A case-control study revealed a significant association between disease and drinking unboiled spring water. The implication of spring water was supported by the presence of faecal contamination in the spring water source. Rapid identification of the possible transmission source and prompt implementation of control measures curtailed the spread of this outbreak.

Foodborne botulism outbreaks following consumption of home-canned bamboo shoots in Northern Thailand.

We report epidemiological investigations of 2 outbreaks of foodborne botulism following consumption of home-canned bamboo shoots in northern Thailand. The first outbreak affecting 4 female and 2 male cases occurred in Mae Sot District, Tak Province, in December 1997. All 6 cases were hospitalized, 4 of whom required mechanical ventilation. All cases experienced neurological features and 4 had gastrointestinal symptoms. One case died, giving a case-fatality rate of 16.7 per cent. A case-control study revealed a significant association (p < 0.01) between the disease and consumption of home-canned bamboo shoots purchased from the same foodshop in the village. The second outbreak of a similar clinical syndrome occurred in Thawangpha District, Nan Province, in April 1998. A total of 13 cases were identified, 9 (69.2%) of whom were female. Nine cases (69.2%) were hospitalized, 4 (30.8%) of whom required mechanical ventilation. Two early hospitalized cases died due to ventilatory failure, giving a case-fatality rate of 15.4 per cent. A case-control study indicated that home-canned bamboo shoots prepared by a local foodshop served as the vehicle for the disease transmission. One bamboo shoot specimen from one affected house was positive for botulinum toxin type A by enzyme-linked immunosorbent assay and mouse antitoxin bioassay. Improper home-canning procedures for bamboo shoot preservation were similarly detected in both outbreaks although performed by different merchants. Prompt recognition and treatment of the disease are essential in reducing the fatality rate. Safe home-canning procedures should be widely distributed and instructed to persons who perform bamboo shoot preservation for sale.

A report of an outbreak of postoperative endophthalmitis.

We report an outbreak of endophthalmitis following cataract extraction or secondary intraocular lens (IOL) implantation in a 400-bed general hospital in northern Thailand. From December 1997 to September 1998, of 329 patients who had undergone cataract extraction or secondary IOL implantation in the hospital, 31 (9.4%) developed postoperative endophthalmitis. The interval between the operation and the clinical diagnosis of endophthalmitis ranged from 5 to 74 days with a median of 15 days. Of the 31 cases of endophthalmitis, 18 occurred in phacoemulsification (PE) with IOL, 11 in extracapsular cataract extraction (ECCE) with IOL, and 2 in secondary IOL implantation. Patients who had undergone PE with IOL had a significantly higher rate (12.4%) than those of ECCE with IOL (6.3%). The infection rates also increased with the order of the operations within each operation period (morning or afternoon); later operations were at higher risk. Our findings detected defects in sterilization for the surgeries including possible inadequacy in the autoclave sterilization of surgical instruments, insufficient exposure time with 2 per cent activated glutaraldehyde solution (about 15-30 minutes) for sterilizing some surgical instruments, and the use of multiple-dose intraocular irrigating solution. This outbreak of endophthalmitis emphasizes the necessity to monitor regularly the practice of sterilization/disinfection in hospitals for prevention and control of nosocomial infections.

Screening assessment of persons 40-59 years of age in rural Thailand by a mobile health unit.

This paper reports a screening survey using a mobile unit to determine the prevalence of chronic disorders among persons aged 40-59 years in rural Thailand. A total of 4,812 persons from all the 54 rural villages in Mae Sot District, Tak Province, northern Thailand, were interviewed and examined in 1995. A higher proportion (59.3%) of men were current tobacco smokers than among women (40.4%). A higher proportion (69.6%) of men were current alcohol drinkers compared with women (38.6%). Cutting/piercing was the most frequently reported injury, followed by falls. About half (47.9%) of the persons surveyed had a body mass index (BMI) between 20 and 24.9 and only 2.6 per cent had a BMI of 30 or over. The overall prevalence rates of hypertension and diabetes in the persons surveyed were 13.3 per cent and 2.4 per cent respectively. Of the persons screened, 28.8 per cent had borderline-high blood cholesterol (200-239 mg/dl) and 12.9 per cent had high blood cholesterol (> or = 240 mg/dl). About 61 per cent of hypertensive persons, 92 per cent of diabetic persons, and nearly all of those with dyslipidaemia were first detected during this screening programme. Five women with breast cancer and 22 with benign breast disorders were also identified during the survey. A screening programme using a mobile unit may be useful in identifying treatable disorders in rural areas, where existing screening services cannot effectively cover the population at risk.

Effect of dietary modification on changes in serum lipids among rural Thai persons with hypercholesterolemia.

This article reports on the effect of dietary modification on changes in eating patterns and serum lipids among hypercholesterolemic persons aged 40-59 years with no evidence of coronary heart disease in Mae Sot District, Tak Province, between 1995 and 1996. A total of 381 persons with total cholesterol levels > or = 240 mg/dl and triglyceride levels < 400 mg/dl were educated, counseled, and followed-up by the mobile health team at the health centres in the communities. The team comprised both hospital personnel (a physician, a health educator, and public health nurses) and the health centre workers. Of the 381 study persons, 331 (86.9%) completed the one-year follow-up. The participants at one-year follow-up were more likely than at baseline to reduce intakes of dietary fat and cholesterol, whereas, there was an increased intake of vegetables and fruits. The mean total cholesterol level significantly decreased from 258.9 mg/dl at baseline to 236.1 mg/dl at one-year follow-up (p < 0.01), giving an 8.8 per cent reduction. The mean change in low-density lipoprotein cholesterol levels was a 26.0 mg/dl decrease (p < 0.01), yielding a 15.1 per cent fall. The mean high-density lipoprotein cholesterol level increased from 44.6 mg/dl at baseline to 46.8 mg/dl at one-year follow-up (p < 0.01). The proportion of those who had a body mass index of < 25 slightly increased from 70.7 per cent at baseline to 72.5 per cent at one-year follow-up. The dietary intervention program by the mobile team may be useful for lowering serum cholesterol among the rural population with hypercholesterolemia.

Prevalence of disabling conditions in a rural northern Thai community: a survey conducted by village health communicators.

This report presents a survey of disabling conditions conducted by village health communicators (VHCs) in 1989 in a rural northern Thai community. The disabled were first identified by a VHC and then examined clinically and socially by a health care team both to confirm the clinical diagnosis and to formulate an appropriate treatment plan. The overall prevalence rate of disabled persons was 6.3/1,000 population. The prevalence rate was higher for males than females and increased with age. Locomotor disability (48.8%) was the most commonly identified disabling condition, with visual disability (27.8%) the next most common. Communication disorders, mental retardation, and psychosis constituted the remaining 23.4%. Of the locomotor disabilities, the major disabling conditions were poliomyelitis, congenital malformations, traumatic amputations, and cerebral palsy. Unoperated cataract accounted for 72.0% of all cases with visual disabilities. While the true magnitude of the disability problem may be somewhat understated, the data reported in this study clearly reveal that there are many persons with untreated disabling conditions in rural communities, and that a significant number of them can benefit from medical treatment and rehabilitation. A survey utilizing VHCs may be helpful to identify the disabled in rural communities.

Epidemiologic characteristics of drivers, vehicles, pedestrians and road environments involved in road traffic injuries in rural Thailand.

This report presents descriptive epidemiology of vehicle-related crashes that caused severe injuries in a defined geographical area in northern Thailand, conducted to determine the nature of injuries and factors that contributed to the crashes. In each incident, the driver and other victims were identified and interviewed by a trained public health worker using a standard investigation form. During 1991, 286 single-vehicle crashes (66.4%), 117 crashes with other vehicles (27.1%), and 28 crashes involving pedestrians (6.5%) occurred in the area. These crashes injured 581 persons (551 vehicle occupants and 30 pedestrians), of whom 36 (6.2%) died. The vehicles involved in the crashes included 11 bicycles (2.3%), 371 motorcycles (78.6%), and 90 other motor vehicles (ie, pick-up trucks, lorries, and cars) (19.1%). Motorcycle-related crashes accounted for the majority of injuries and deaths. Driver risk factors for traffic injuries, such as alcohol consumption, lack of a valid driving licence, limited driving experience, and being a teenage driver, occurred more commonly among drivers of motorcycles than of other motor vehicles. Poor vehicle conditions and road environments reported in some incidents may have posed additional risks. Pedestrian factors, including young and old age, and alcohol use, may also have contributed to the occurrence of pedestrian injuries. Our system of data collection using an investigation form can provide relevant information, leading to the development of appropriate accident prevention programs for the community.

A common source foodborne outbreak of E1 Tor cholera following the consumption of uncooked beef.

In July 1988, an outbreak of cholera with 71 culture-confirmed cases of biotype El Tor, serotype Ogawa, occurred in a non-endemic area in Mae Sot district, Tak province. Fifty-two cases had diarrhea and 19 had asymptomatic cholera infection. No cases died. Epidemiological investigation revealed a significant association between cholera infection and the consumption of uncooked beef. Increased risk of cholera infection was observed when the incriminated beef was kept at room temperature and consumed later without cooking. The beef was possibly contaminated with V. cholerae O1 from an infected butcher who may have contracted the disease from his foreign worker who was found to have asymptomatic cholera infection. Early detection of the outbreak and rapid identification of transmission source permitted prompt appropriate control measures which, therefore, prevented the outbreak from spreading to other communities. As outbreaks of foodborne diseases, including cholera, have been reported frequently after the consumption of raw food in many parts of Thailand, preventive educational efforts should be directed towards modifying the traditional behavior patterns of consuming raw food among these Thai people.

A survey of knowledge, attitude and practice of the prevention of dengue hemorrhagic fever in an urban community of Thailand.

To evaluate the effect of a health education program on the prevention and control of dengue hemorrhagic fever (DHF) in the municipality of Mae Sot, Tak Province, a survey of adult residents, mainly housewives, was conducted in late April 1990 to assess their knowledge of DHF and practice of preventive methods. A total of 417 respondents from 417 households selected by a systematic-cluster sampling method were interviewed. More than 90% of them knew that the disease is transmitted by Aedes mosquitos and indicated water jars and water retention in the houses as the common breeding places. However, the other two common breeding places, ant-traps and cement baths, were less frequently mentioned. This finding was consistent with the greater proportion of respondents who reported no larval control methods for these two kinds of containers than for the others. Covering water containers was the most common practice to prevent mosquito breeding in drinking-water containers whereas addition of abate (temephos sand granules) or changing stored water frequently was commonly used for non-drinking water storage. Larval control for ant-traps was mainly accomplished by the addition of chemicals, including abate, salt, oil or detergent. Health education efforts in this area could induce the majority of respondents to accept themselves as responsible for the Aedes control program. Health education by health personnel played an important role in disseminating DHF information and prevention methods. Radio and television were the main effective mass media for public health education on DHF in this area.

Effect of health education on community participation in control of dengue hemorrhagic fever in an urban area of Thailand.

Dengue hemorrhagic fever (DHF), a disease transmitted by Aedes mosquitos, remains a serious public health problem in Thailand. This paper describes the effect of health education efforts on a community-based DHF vector control program in the municipality of Mae Sot District, Tak Province, northern Thailand, from 1988 through 1990. In 1988, public health education on DHF and larval control through mass media, lectures and discussions reduced the Aedes Breteau index from 241 in March to 126 in June 1988. In 1989 and 1990, twice a year house-to-house visits by trained health workers were added to the health education campaigns. Aedes larval indices were decreased far more in the epidemic year of 1990 than in 1989. During this 3-year period, water-storage containers for drinking, washing, bathing and ant-traps were the primary sources of larval habitats, accounting for about 90% of the total breeding places. Reduction of Aedes larvae in these sources was due to various larval control measures. By August 1990 water containers for non-drinking purposes were the remaining important breeding places. The introduction of larvivorous fish may be an effective method of larval control for these containers. Most houses were supplied by public piped water system; however, a shortage of piped water for a period of time resulted in a significant increase in the number of water containers. An adequate water supply to the community should be provided continuously to prevent creation of new breeding places. Modifying behavioral practices to reduce domestic man-made water containers should be encouraged.

Assessment of socio-economic, functional and medical problems among the elderly in one rural community of Thailand.

A survey of persons aged 60 years and over in Mae Sot in Tak Province, Thailand was conducted in 1989 to determine the prevalence of socio-economic, functional and medical problems. A total of 567 elderly persons from 8 villages systematically selected from 54 villages outside the municipality were interviewed and examined. Ninety-eight percent of them lived with their children or relatives. There were few elderly persons reporting difficulty performing basic physical activities of daily living due to the very low proportion of older elderly in this area. 13.3% of men and 14.5% of women reported some degree of urinary incontinence; however, most of them complained of only slight incontinence at occasional intervals. 62.4% of the study elderly had a body mass index below 20. The mean body mass index for men (19.5) was slightly higher than that for women (18.7). One hundred and two out of the 567 elderly surveyed were found to have hypertension and 51% of these hypertensives were newly diagnosed during this study. There was no association between the prevalence rate of hypertension and any of the other studied variables, including age, sex, educational level and smoking habits. The overall prevalence rate of diabetes in these elderly people was 1.6%. The mean body mass index of the diabetic group (23.1) was significantly (p less than 0.05) greater than that of the non-diabetic group (19.1). Special homes for the aged may become necessary in the future as young people migrate away from rural areas where their aging parents live to urban areas.(ABSTRACT TRUNCATED AT 250 WORDS)

An outbreak of El Tor cholera in an institution for the mentally retarded in Nonthaburi, June-July 1987.

In June and July 1987, an outbreak of cholera caused by V.cholerae O1, biotype El Tor, serotype Inaba, occurred in an institution for the mentally retarded in Nonthaburi. Of the 447 retarded inmates, 74 were found to be infected and one died. Epidemiological investigation revealed that the inmates with severe mental retardation who ate food in their own sleeping-room were significantly (p less than 0.001) more likely to be infected than those taking food in the dining-room. We hypothesize that the liquid diet commonly served to the more severely mentally retarded may have increased the risk of infection by more rapid gastric emptying. The long average period of time for meal consumption among these individuals may have allowed the organisms to multiply to a level capable of causing disease. Contamination of food with cholera might have occurred during food handling in the kitchen or within the sleeping-room where overcrowded conditions and poor personal hygiene facilitated person-to-person spread of infection. Prompt implementation of control measures effectively terminated cholera transmission in the outbreak.

A survey of knowledge about AIDS and sexual behavior in sexually active men in Mae Sot, Tak, Thailand.

A survey of 15-34 year old men in Mae Sot, Tak, was conducted in December 1989 to determine their knowledge about AIDS, HIV transmission, and sexual behavior to guide future AIDS prevention programs. A total of 172 men from the municipality (urban) and 311 men from the surrounding villages (rural) were interviewed. More than 90% of both groups possessed knowledge about the existing modes of HIV transmission, however, there were some who had the mistaken belief that AIDS can be spread by mosquito bites, using public toilets, or through various forms of casual contact. These misconceptions in the community underscore the need for more education designed to counteract them. Although nearly all of them knew that condoms can prevent infection, only half of the urban and one-third of the rural sexually active men had ever used a condom during their sexual intercourse with prostitutes. However, condom use increased over time. Since a number of these men first engaged in sexual intercourse at an early age, the promotion of health education about AIDS in the schools is essential.

Effect of health education and condom promotion on behavioral change among low socioeconomic prostitutes in Mae Sot, Tak, Thailand.

A study was conducted to determine the effect of preventive educational efforts among 621 female prostitutes in Mae Sot, Tak Province, in 1989. The intensive health education program at a personal level and free condom distribution to the prostitutes began in March and June 1989, respectively. The proportion of prostitutes' sexual partners using condoms increased from 13.5% in January 1989 to 50.4% by December 1989. The reported increase in condom use was supported by the decline in the incidence rate of gonorrhea among the prostitutes during the same period. Anal intercourse was not commonly practised in these women and decreased from 9.7% in January to 1.8% in December 1989. None of the prostitutes interviewed throughout the year reported using intravenous drugs, nor reported having a steady sexual partner who was an intravenous drug user. None out of 248 prostitutes tested in January 1989 were HIV-1 seropositive. After that throughout the year, 15 of 373 (4.0%) additional prostitutes in this area were found to be seropositive on their first test. Ten out of 405 (2.5%) initially-seronegative prostitutes who were subsequently tested at 3-month intervals became seropositive. The effect of health education and condom promotion among our study prostitutes was modest. Similar studies are needed to evaluate the programs in other settings of Thailand, particularly in areas with high prevalence of HIV-1 infection.

Sociodemographic characteristics and incidence of gonorrhoea in prostitutes working near the Thai-Burmese border.

A study was conducted to determine the sociodemographic characteristics and incidence of gonorrhoea among the prostitutes working in Mae Sot District, Tak in 1988. Of the 238 prostitutes included in the study, 130 were Thai and 108 were Burmese. About 55% of the Thai group and 65% of the Burmese engaged in prostitution before being 19 years old. Most of them experienced sexual intercourse at early age of life. The charge per sex partner ranged from 50-500 baht (US$2-20), with a median of 100 baht (US$4) for both groups. The Thai prostitutes had a significantly higher mean number of clients per day and received more Thai clients than the Burmese. Anal and oral sex were not commonly practised among these prostitutes. Approximately 14% of the prostitutes' clients in both group used condoms. The mean infection rate of gonorrhoea was significantly greater in the Thai prostitute group than the Burmese. Multiple linear regression analysis revealed that the infection rate of both groups was inversely associated with the percentage of client using condoms and the duration of having been prostitutes, and positively associated with the percentage of Thai clients. The program for STD control should be directed towards the increase use of condoms, spermicides, and other barrier methods, and massive health education program on safer sex to this high risk group and the general population.

Surveillance of neonatal tetanus in Thailand, 1977-1986.

Information on the morbidity and mortality of neonatal tetanus was reviewed to evaluate the impact of the immunization programme among pregnant women in Thailand from 1977. We also analysed the epidemiological characteristics of investigated neonatal tetanus cases during the period 1984-1986. The neonatal tetanus case rate declined from 72.1 per 100,000 livebirths in 1977 to 53.7 per 100,000 livebirths in 1986. Reduction in the incidence rate was inversely associated with increasing vaccination coverage of pregnant women with tetanus toxoid. The ratio of male to female neonatal tetanus was 1.5 to 1. Approximately 95 per cent of the cases occurred within the first 14 days of life, with the highest number recorded at 6-8 days of life. The majority of investigated cases were infants who became ill following delivery assisted by traditional birth attendants or relatives of mothers. About 88 per cent of these cases were infants whose mothers had no tetanus immunization. Razor blades and bamboo splits were the most frequently used instruments for cutting the umbilical cord. Strategies to control neonatal tetanus in Thailand should include immunization of pregnant women with tetanus toxoid, and more comprehensive training and supervision of untrained birth attendants.

Several sporadic outbreaks of El Tor cholera in Sunpathong, Chiang Mai, September-October, 1987.

From September through October 1987, a cholera outbreak involving 59 cases of biotype El Tor, serotype Inaba occurred in Sunpathong district, Chiang Mai. No cases died. Twenty-seven cases were males and 32 were females. The age ranged between 4 months and 85 years, with a median of 36 years. The outbreak affected 7 small communities, and showed different vehicles of infection. Six housewives and one girl were infected with cholera in the first localized outbreak. The transmission of infection appeared due to the consumption of packed food contaminated by an infected food handler. In the second localized outbreak, 6 young males acquired cholera after eating uncooked fish harvested from a canal contaminated with cholera organisms. Another outbreak of cholera with 24 culture-confirmed cases occurred among guests at a funeral held in one rural village. The source of infection was traced to uncooked pork contaminated from an infected butcher: Early detection of infected persons, rapid identification of possible vehicles of transmission, and prompt implementation of control measures effectively curtailed the extension of these outbreaks.

Foodborne disease outbreaks of chemical etiology in Thailand, 1981-1987.

A study was conducted to determine the current situation of chemical foodborne outbreaks in Thailand for the period 1981-1987. Seventy-three outbreaks of chemical poisoning involving 1236 persons of whom 54 died were reported. Twenty outbreaks affecting 722 cases were caused by insecticide poisoning and methomyl was the most commonly recognized insecticide involved. Poisonous plants were responsible for 43 outbreaks with 420 cases. Mushroom poisoning was the most common entity (21 outbreaks, 211 cases), with plant seed poisoning next (9 outbreaks, 179 cases). There were 8 outbreaks following consumption of poisonous seafoods. Mussels were identified to be the vector in the outbreak of PSP. Horseshoe crabs which served as the vehicles for 4 outbreaks were also suspected to be associated with PSP. Puffer fish accounted for the remaining 3 outbreaks involving 6 cases of tetradotoxin poisoning. More complete reporting and more effort in outbreak investigations are needed for appropriate preventive and control measures.

Epidemiology of human rabies post-exposure prophylaxis in Bangkok, 1984-1986.

A study was conducted to determine the current situation of human rabies post-exposure prophylaxis (PEP) in Bangkok for the period 1984-1986. A review of all Bangkok residents receiving PEP at the Queen Saovabha Memorial Institute revealed an increasing incidence rate of PEP from 10.1 cases per 10,000 persons in 1984 to 12.6 cases per 10,000 persons in 1986. The highest incidence rate was observed in young males aged 5-14 years. About 68% of individuals receiving PEP had exposures to bites, especially by dogs, and nearly 30% of PEP cases were due to non-bite exposures. Dogs were responsible for 90% of PEP cases, of which 59% were exposed to stray dogs. Exposure to domestic dogs and cats constituted about 36% of PEP. Approximately 55% of persons received PEP for exposures to animal sources not proven rabid. To reduce the number of PEP, the programme should be directed towards the swift reduction of susceptible animals, which can be achieved by effective elimination of stray dogs and immunization of domestic dogs and cats. Massive health education to the public emphasizing the importance of prevention and control of rabies should be undertaken. The programme for control of rabies can be effective if there is an increased awareness and cooperation among professional people, health personnel, and other people in the community.