Subject(s)
Opisthorchiasis/transmission , Opisthorchis/physiology , Snails/physiology , Animals , Female , Fishes , Humans , Snails/parasitology , ThailandABSTRACT
In a large village in north-east Thailand, the overall prevalence of Opisthorchis viverrini infection (based on Stoll's quantitative egg count) was 89.5% in a total population of 1651 individuals. The prevalence was 32% in children under 5 years, 90% in those aged 5-9 years, and averaged 95.6% in age groups above 10 years. The mean faecal egg output (indicative of intensity of infection) was highest in the 40-49-year age group and remained relatively constant through older ages. In all age groups the prevalence and intensity of infection in both men and women were similar.A history of eating raw freshwater fish occurred more frequently in infected persons than in those uninfected. The following symptoms occurred significantly more frequently in groups with higher intensities of infection: weakness, flatulence or dyspepsia, and abdominal pain in the right upper quadrant. Nevertheless, infected persons did not report a reduced ability to work. Anorexia, nausea, vomiting, and diarrhoea were only weakly correlated with the intensity of infection. A palpable liver occurred more frequently in the infected groups and was correlated with intensity of infection. Icteric conjunctivae were observed in 2.2% of infected persons but not in the uninfected. Some 5-10% of the population had symptoms that were attributable to opisthorchiasis.
Subject(s)
Opisthorchiasis/epidemiology , Adolescent , Adult , Aged , Child , Child, Preschool , Feces/parasitology , Female , Humans , Infant , Male , Middle Aged , Opisthorchiasis/diagnosis , Parasite Egg Count , Physical Examination , Rural Health , ThailandABSTRACT
A modified quick-Kato technique and the Stoll dilution method for the diagnosis of Opisthorchis viverrini infection were compared from the standpoints of both replicability and sensitivity. One Stoll dilution preparation and two modified quick-Kato smears were prepared from single stool specimens collected from 221 persons in a village in north-eastern Thailand. Stool examinations were made in duplicate for each technique by two examiners, and the averages of the raw egg counts were used to estimate the intensity of infection. Statistical analyses revealed that the modified quick-Kato technique was slightly more sensitive, and thus would detect more positives, but was lacking in replicability and hence less suitable for measurement of individual intensity of infection. We therefore recommend the Stoll dilution technique for field surveys and measurement of individual intensity of O. viverrini infection.
