ABSTRACT
Saraburi Province, Central Thailand has been a paragonimiasis-endemic area since 1956. This study compared the prevalences of human paragonimiasis in two villages near Chet Khot Waterfall, Kaeng Khoi District, investigated in 1984-1985 and 2005. The results from the 1980s showed 6.3% and 1% of villagers were positive for Paragonimus eggs in sputum and stool, respectively. In 2005, Paragonimus eggs were not found in feces or sputum. An IgG-ELISA for paragonimiasis was conducted on 33 serum samples collected in the 1980s, 23 collected in 2005 and 25 diagnosed with other parasitic infections. Ninety percent of the samples from the eighties were positive for paragoimiasis, and 43% from 2005 were positive, equivalent to 10.9% and 4.9% of the total population examined in the 1980s and 2005, respectively. Serodiagnosis is currently the best method for detecting paragonimiasis. The positive cases in the 1980s were age 10-60 years and in 2005 were age 34- 67-years-old. The prevalence and intensity of Paragonimus metacercariae in fresh Waterfall crabs collected from Chet Khot Waterfall were significantly lower in the 1980s than in 2005. The prevalence of paragonimiasis in this endemic area has decreased to the level that no egg-producing cases were detected. No infections were found in villagers age < 30 years, despite the high density of metacercariae in the crabs, indicating a change in the habit of eating raw food among the younger people.
Subject(s)
Adult , Animals , Brachyura/parasitology , Child , Endemic Diseases , Enzyme-Linked Immunosorbent Assay , Feces/parasitology , Female , Humans , Male , Middle Aged , Paragonimiasis/blood , Paragonimus/isolation & purification , Parasite Egg Count , Prevalence , Serologic Tests , Shellfish/parasitology , Sputum/parasitology , Thailand/epidemiology , Young AdultABSTRACT
The preparative crude extract of Paragonimus heterotremus was fractionated by isoelectric focusing. Fractions at pH 5 which contained a specific antigen with a relative molecular weight of 31.5 kDa were pooled and used in an indirect enzyme-linked immunosorbent assay (ELISA) and immunoblot analysis for diagnosis of human paragonimiasis. The sensitivity and specificity of ELISA were found to be 100% and 99% respectively. The band of 31.5 kDa antigenic component was found to give consistent reaction with paragonimiasis sera. The sensitivity, specificity and predictive value (positive and negative) of immunoblot analysis for the 31.5 kDa band were all 100%.