Risk behaviours and comprehension among intravenous drug users volunteered for HIV vaccine trial.

Out of 91 volunteers enrolled for the HIV vaccine trial, only 33 volunteers were eligible for vaccination. Of 33 volunteers recruited, 59 per cent of them had incomes of more than 5,000 Baht/ month. The median duration of drug addicts was 15 years (range 1-26 years) and 42 per cent never used condoms during sexual intercourse. As far as consent comprehension was concerned, all of them understood.

Pasteur oral cholera vaccine: studies of reactogenicity, clinical acceptability and immunogenicity in human volunteers.

Pasteur cholera vaccine consists of isolated antigenic fractions from V. cholerae El Tor Ogawa and Inaba. Enteric coated microgranules were prepared from antigen lyophilisate. Three doses of this vaccine were administered orally to 19 healthy young Thai adults at one week intervals. None of the volunteers experienced untowards reactions. The vibriocidal antibody responses manifested a significant antibody rise (> or = 4 fold) to serovar Inaba in 8 vaccinees (42.1%) and Ogawa in 4 (21.1%). Five and 6 vaccinees (26.3% and 31.6%) showed a > or = 4 fold rise of IgG and IgA anti-LPS, respectively.

Gnathostoma larva migrans among guests of a New Year party.

An outbreak of Gnathostoma larva migrans occurred among guests of a New Year's party in Chachoengsao, Thailand. Nine people who consumed a raw fish dish called 'Hu-sae' contracted the disease. Five of them developed gastro-intestinal symptoms consisting of nausea, vomiting, abdominal cramps and diarrhea as early as within the first 24 hours, while in the other four, symptoms started on the following day. After the initial symptoms pertaining to the gut, malaise, chest discomfort, cough, myalgia, weakness, itching and migratory swellings were experienced. Eosinophilia was demonstrated in every patient with a mean (+/- SE) count of 5,516 +/- 1,010 cells/cu mm. Detection of antibody against aqueous extracts of G. spinigerum adult antigen using an enzyme-linked immunosorbent assay showed a titer of 1:1,600 or greater in every patients except one who had a titer of 1:400 (positive greater than or equal to 1:400). This outbreak illustrates the high attack rate when heavily infected fish are consumed.

Health status of Thai volunteers in a cholera vaccine trial.

One hundred and seventy-one male adults were screened in recruitment of volunteers for a cholera vaccine trial. A full medical history and a physical examination were performed on each subject. The percentages of subjects vaccinated against cholera and typhoid within twelve months were 4 and 1 per cent respectively, while 88 and 15 per cent respectively had been vaccinated more than a year. Biochemical screening revealed abnormal liver function tests in 40.7 per cent, specifically alkaline phosphatase (8%), glutamic oxaloacetic transaminase (8%), glutamic pyruvic transaminase (4.7%), total bilirubin (10%) and globulin (34%). Ten (6%) of the volunteers were positive for hepatitis B surface antigen (HBs-Ag). The total white cell count was elevated in 13.5 and 81.9 per cent had eosinophilia. Stool examination revealed infection with Hookworm (54.9%), Opisthorchis viverrini (29.8%), Strongyloides stercoralis (5.3%), Endolimax nana (3.5%), Giardia lamblia (5.3%) and Taenia saginata (2.9%). Few volunteers (13.4%) had abnormal microscopic examination of urine sediment. Only 57 subjects were considered suitable to be volunteers. Each of these subjects had no significant past medical, surgical or psychological illness. None had been vaccinated against cholera within the previous 12 months and no subject had abnormalities on physical examination or routine biochemical and haematological screening. The large number of subjects excluded from recruitment (67%) emphasized the importance of proper screening of volunteers for any vaccine trial.

Socio-economic status and prevalence of intestinal parasitic infection in Thai adults residing in and around Bangkok metropolis.

Socio-economic factors relating to prevalence of intestinal helminthic infections were studied in 189 Thai adults residing in and around Bangkok. Questionaires were used to interview each individual about occupation, income, family occupation, family income and educational level. All participants were subjected to three microscopic stool examinations and to stool cultures for Stronglyoides stercoralis. Of 189, 34 were students (20%), 60 were unemployed (35%), and the remainder were employed in private or public sectors. The overall average personal incomes were low (less than US$ 1,000/year), while 56 per cent of them came from middle class families (US$ 2,000-4,000/year). Regarding the educational level, only 151 persons answered this question. Fourteen (9.3%) did not complete primary school; 20 (13.2%) completed primary school; 97 (64.2%) completed secondary or vocational school and 20 (13.2%) were university graduates. Prevalence of intestinal parasitic infection was 25 per cent (47/189) and 23.4 per cent (11/47) of infected individuals had multiple infections. The distribution among them was as follows: strongyloidiasis 30.5 per cent, hookworm 25.5 per cent, giardiasis 23.4 per cent, opistorchiasis 17 per cent, amoebiasis 12.8 per cent, trichuriasis 4.3 per cent, taeniasis 2 per cent and ascariasis 2 per cent. There were no statistical differences in incomes, occupations, family incomes and educational levels between infected and uninfected individuals.

Relationship of vibriocidal antibodies to history of cholera vaccination in Thai adult volunteers.

Vibriocidal antibodies were determined by microtechnique in 5 groups of Thai adult volunteers who had never received or had received cholera vaccination within one year, more than one to five years ago, more than five to ten years ago and more than ten years ago respectively. Detailed questionnaires about socioeconomic status, educational levels and environmental factors were presented to every volunteer. There were no differences statistically in incomes, educational levels and environmental factors among the groups. It was found that the reciprocal geometric mean titers of antibodies in volunteers who had never received cholera vaccination was generally low. The reciprocal geometric mean titers of the volunteers who had received cholera vaccination within one year were statistically different from other groups (p = 0.05). There was no correlation between blood groups of volunteers and vibriocidal antibodies.

Immune responses following killed whole vibrio-B subunit oral cholera vaccine in human volunteers.

Immunogenicity of killed whole vibrio and B subunit oral cholera vaccines in American and Thai volunteers were analysed in terms of significant rise of antibody titre. Three doses of 2 x 10(11) killed vibrios and 5 mg of cholera toxin B subunit were given at two-week intervals. There were no differences in the percent of volunteers with significant rise of serum immunoglobulin G and secretory immunoglobulin A (sIgA) to cholera toxin. However, the percent with significant rises of serum antibody to whole cell V. cholerae Inaba measured by vibriocidal titre and serum immunoglobulin G, and secretory immunoglobulin A to lipopolysaccharide (LPS) measured by ELISA in American volunteers were significantly different from those in Thai volunteers (89% VS 45%, 68% VS 9% and 53% VS 0%, respectively) (p less than 0.05).

Adherence of human eosinophils to infective filariform larvae of Necator americanus in vitro.

Eosinophilia is common in hookworm infection but the interaction between eosinophils and the larval stage of the parasite is poorly understood. The present study was conducted to test the ability of the eosinophils to adhere to infective filariform larvae of Necator americanus in vitro. Adherence of eosinophils to the larvae was found to be serum dependent. Antibody facilitated eosinophil adherence but this was maximal in the presence of complement. The adherence was greatly diminished by EGTA treated normal human serum (NHS) and was completely abolished when NHS was treated with either EDTA or heat-inactivation, suggesting that the process can be facilitated through complement activation via the alternative pathway. As with other nematodes, the surface of hookworm larvae appeared to be both antigenic and complement-activating. Although it is not known whether eosinophil adherence has any larvicidal effect, the present study demonstrated for the first time a definite interaction between human eosinophils and hookworm filariform larvae.

ELISA for immunodiagnosis of human gnathostomiasis.

An ELISA for immunodiagnosis of human gnathostomiasis using a crude water extract of third-stage larvae of G. spinigerum as antigen, and alkaline phosphatase labelled goat antihuman IgG in the indicator system was developed and evaluated. At the titre of 1:400 and above positive results were observed in 100% of 4 parasitological confirmed and 10 eosinophilic meningo-encephalitis (EME) typical of gnathostomiasis cases, 56% of 160 cutaneous migratory swelling cases, 33% of 24 cases with EME typical of A. cantonensis infections, 23% of 92 cases with other parasitic infections and 1.5% of blood donors. The overall sensitivity was 59% and specificity 84%. The predictive value was 77%. The results indicated that ELISA is potentially useful for immunodiagnosis of gnathostomiasis but improvement of sensitivity and specificity is needed.

Zinc in the pathogenesis of hookworm anaemia.

Serum zinc levels in 90 patients with hookworm infection were compared with those of 26 uninfected controls. The severity of infection was graded in terms of haemoglobin levels as well as egg loads. The results showed that the serum zinc levels in anaemic patients with hookworm infection were significantly lower than those of the controls (p less than 0.01).

Clinical trial of albendazole in hookworm infection.

A clinical trial of albendazole (Zentel R) was carried out at the Hospital for Tropical Diseases in 1981. Thirty-five patients with hookworm infection were divided into 2 groups A, B and treated with a single dose of albendazole 400 mg and 600 mg respectively. The age of the patients ranged from 12 to 66 years and their weights ranged from 25 to 62 kilograms. Concentration and Stoll egg count methods were done at pretreatment, day 14 and day 21. At each interval two aliquots from each of the two faecal specimens were collected. The geometrical mean of EPG in Group A and B were 5406 and 5617 respectively. The cure rate in patients with less than 5000 EPG was 75% on day 21 in Group A and 67% in Group B. The mean percentage egg reduction was 95% in Group A and 99% in Group B. In patients with a higher egg out-put, the cure rate on day 21 was 50% in Group A and 29% in Group B. The mean percentage egg reduction was 91% in Group A and 93% in B. The side effects were mild and transient.

The beneficial effect of a high protein-calorie diet on a malnourished patient during hospitalization.

The effect of a high protein-calorie diet was studied on a 45 year-old Thai woman suffering from severe nutritional deficiency i.e. anaemia and multiple vitamin deficiencies. Several clinical chemical parameters in blood, red cells and urine for the assessment of the nutritional status were investigated at the time of admission to the hospital and after two and four weeks hospitalization. The patient was only treated with the high protein-calorie diet of the hospital and did not receive any vitamin supplementation. Only with this treatment the clinical signs disappeared within 4 weeks and also all the biochemical abnormalities returned to normal. With this study it is demonstrated that high multiple vitamin supplementation may not always be necessary for the good treatment and recovery of hospitalized patients suffering from vitamin deficiencies.