Dependence and active life expectancy of the elderly population living in the central region of Thailand.

OBJECTIVE: To determine the prevalence and the independent socio-economic factors with respect to the dependence status of the Thai elderly population living in the central region and to calculate the active life expectancy (ALE) based on the results of this survey and abridged life tables for Thailand. DESIGN: A cross-sectional mulitistage random sampling survey. SETTING: Communities in the central region, Thailand. SUBJECTS: 723 elderly subjects. RESULTS: Mean age and its standard deviation (SD) of the 723 recruited subjects were 69.9 and 7.3 years, respectively. Forty three per cent of the subjects were men. Mean values (SD) of the BAI score and the CAI score were 18.78 (2.6) and 6.47 (2.4), respectively. Except for housework, elderly women had a higher prevalence rate of dependence on activities of daily living (ADL) compared with elderly men. Seven univariate factors of the BAI and the CAI were demonstrated. According to the multiple linear regression analysis by entering all univariate factors of the BAI and the CAI except "working status", independent factors of both the BAI (adjusted R2 = 0.051) and the CAI (adjusted R2 = 0.146) were age, sex and writing ability. The prevalence rate (95% confidence interval) of dependence regarding self-care activities of daily living was 5.9 per cent (4.2-7.6%). The rate of dependence increased with age. The female elderly were more dependent on self care than their male counterparts. Although the elderly women live longer than the elderly men, they spend more years in a severely dependent state. Findings on ratios between health and life expectancy demonstrate that Thai men spend more proportional time leading a healthy life than Thai women. CONCLUSION: Prevalence rates of dependence regarding activities of daily living among the Thai elderly living in the Central region were rather high showing the health of elderly women to be worse than that of elderly men. The elderly women spend more years in a severely dependent state although they live longer than the elderly men.

Epidemiological studies of malaria at Pong Nam Ron, eastern Thailand.

Malaria is still a serious health problem in Thailand. Present attempts at controlling the disease by drug treatment and other means remain unsatisfactory. Thus, development of vaccination against malaria is a major research goal of malaria immunology. The objective of this study was to acquire epidemiological base line data for subsequent vaccine trials. A cross-sectional descriptive survey was conducted among 451 local inhabitants during the beginning of the transmission season in June 1989 at Pong Nam Ron District, Chanthaburi Province, Eastern Thailand where malaria transmission was likely to be high. Following the cross-sectional survey weekly morbidity surveillance was started to detect new cases of malaria by using active and passive case detection at the district hospital, local health centers and at neighboring malaria clinics. Entomological observations were made monthly to determine inoculation rates. Forty-six percent of the population were male and 54% female; one third were under the age of 15 and 14% under the age of 5 years. Eighty percent of the adults were married. Sixty percent of the subjects interviewed gave a history of malarial illness in the past. Malaria, malnutrition, abnormal hemoglobin diseases and parasitic infestation were the main health problems in the study area. The annual parasite incidence of malaria was 149.6/1,000 population and two-thirds of them were asymptomatic indicating a semi-immune condition among these subjects. It was difficult to interpret the results of entomological studies due to low density of the malaria vector.

Economic analysis of malaria control for migrant workers in eastern Thailand.

A randomized, double-blind field trial was carried out to compare the economic impact of permethrin-treated nets with that of untreated nets as a method of malaria control. The study was conducted in 261 long-term migrant workers and 138 seasonal agricultural migrant workers in the eastern rural areas known to be highly endemic for multidrug-resistant Plasmodium falciparum infection. One hundred and twenty-six longterm migrants and 59 seasonal migrants used treated nets, while 135 and 79, respectively, used untreated nets. The impregnated-nets program was cost-saving as well as offering improved effectiveness. The net benefit of using a treated net was US$1.17 per worker from the Malaria Division's perspective and US$1.61 per worker from the worker viewpoint. The use of impregnated nets with large-scale primary health care programs likely will be the most cost-effective and cost-beneficial method for controlling malaria in eastern Thailand.

Malaria in a rural area of eastern Thailand: baseline epidemiological studies at Bo Thong.

Malaria is still a serious health problem in Thailand. Present attempts at controlling the disease by drug treatment and other means remain unsatisfactory. Thus, development of vaccination against malaria is a major research goal of malaria immunology. The objective of this study was to acquire epidemiological base line data for subsequent vaccine trials. A cross-sectional descriptive survey was conducted among 253 local inhabitants during the beginning of the transmission season in July 1989 at Bo Thong District, Chonburi Province, Eastern Thailand where malaria transmission was likely to be moderately high. Following the cross-sectional survey weekly morbidity surveillance was started to detect new cases of malaria by using active and passive case detection at the district hospital, local health centers and at neighboring malaria clinics. Fifty-four percent of the population were male and forty-six percent female: nearly a half (48.3%) were under the age of 15 and 17% under the age of 5 years. Eighty percent of the adults were married. Seventy percent of the subjects interviewed gave a history of malarial illness in the past. Malaria, malnutrition, anemia abnormal hemoglobin diseases and parasitic infestations were the main health problems in the study area. The annual parasite incidence of malaria was 169.4/1,000 population and 77% of parasitemic individuals were asymptomatic, indicating the existence of a semi-immune condition among these subjects. Antibody level to crude parasite antigen increased with age. It is hoped that the information obtained from these field studies may be useful in malaria vaccine trials in the near future.

Seroepidemiologic studies of humoral immune response to the Plasmodium falciparum antigens in Thailand.

We have investigated seroreactivity against Plasmodium falciparum crude parasite antigens, the P. falciparum ring-infected erythrocyte surface antigen (Pf155/RESA), as well as against two synthetic peptides (EENV)6 and (EENVEHDA)3 that represent important epitopes of Pf155/RESA. The study population consisted of 421 children and adult Thais living in an area with moderate malaria transmission. We related these serologic findings to some important epidemiologic baseline data collected in the study area. The parasite rate in study subjects was 18.76%. Sixty-two percent were seropositive to crude P. falciparum antigens, 30.3% to the Pf155/RESA antigen, 23.05% to (EENV)6, and 20.17% to (EENVEHDA)3. Antibody responses to crude P. falciparum antigens and to Pf155/RESA were age dependent and increased with exposure. There was evidence that Pf155/RESA antibodies might play a role in protective immunity in this population. Since Pf155/RESA is a potential vaccine candidate antigen, the information obtained from these field studies will provide some seroepidemiologic baseline data for subsequent vaccine trials.

Human behavior in relation to selection of malaria treatment.

People in rural areas usually help themselves when malaria attacks by using a drug preparation under the name of "ya-chud" bought from the grocery in the village. The objective of this study was to determine the behavior towards malarial treatment of local inhabitants in two malarious areas in eastern Thailand. Groups of 271 and 131 local inhabitants in villages in Pong Nam Ron and Bo Thong Districts, respectively, aged more than 15 years were interviewed regarding health behavior in seeking care when they became ill with malaria. Forty-two percent of the population at Pong Nam Ron and fifteen percent at Bo Thong went to drug-stores or groceries when they developed minor illness, while 85.2% of the subjects interviewed at Bo Thong went to the local health center. However, when they became severely ill, treatment-seeking patterns were similar in the two study areas. Ninety-four percent of the subjects interviewed at Bo Thong and eighty-seven percent at Pong Nam Ron gave a history of having used ya-chud in the past. On average, a set of ya-chud for malaria infection consists of 3-5 drugs: antimalarial drugs together with others such as analgesic-antipyretics, steroids, anti-histamines, vitamins and antimicrobial agents (tetracycline). The price of one ya-chud varied from 3-9 baht. Such improperly use of antimalarial drugs in malarious areas can result in treatment failure and cause the development of drug resistance, which is a problem in the malaria control program in Thailand.

The effectiveness of chemoprophylaxis against malaria for non-immune migrant workers in eastern Thailand.

A randomized, double-blind field trial was carried out to compare the effectiveness of mefloquine plus sulfadoxine-pyrimethamine (MSP) with that of sulfadoxine-pyrimethamine (SP) in chemoprophylaxis against malaria. The study was conducted in 193 migrant workers in the eastern rural areas of Thailand which are known to be highly endemic for multidrug-resistant Plasmodium falciparum infection. MSP was found to be more effective than SP in the suppression of both P. falciparum and P. vivax parasitaemias, when administered weekly for 12 weeks (P = 0.0014). Complete suppression of P. falciparum was achieved by MSP while 8 subjects receiving SP developed parasitaemia. One subject in the MSP group developed P. vivax parasitaemia, compared with 4 in the SP group. However, in view of the reported complications associated with the use of long-acting sulphonamides, some of which can be life threatening, prophylactic regimens containing sulfadoxine, though proved efficacious, must be used with extreme caution.

Rifampicin-erythromycin combination for the treatment of gonococcal urethritis in men.

A total of 184 men with uncomplicated gonococcal urethritis were treated with a single oral dose of rifampicin 900 mg and erythromycin stearate 1 gm. The cure rate on day 3 was 95.1%, 175 were cured and 9 failed (4.9%). Of all the Neisseria gonorrhoeae isolated, 86 were PPNG (46.7%). There was no difference in failure rate among patients with PPNG or with non-PPNG. With the exception of self-limited gastrointestinal disturbance, side effects were minimal. The value of this combination for the treatment of uncomplicated gonococcal urethritis in men is promising and deserves further study.