Methylene blue staining method for identification of Opisthorchis viverrini egg.

Methylene blue staining method was used to distinguish O. viverrini eggs from Haplorchis taichui and Prosthodendrium molenkampi eggs. All eggs were obtained from dissected adult worms, fixed in 10% formalin, and stained with methylene blue prior to light microscopy observation. The distinct musk-melon-like texture of the O. viverini eggshell surface and the thread-like texture of H. taichui eggshell surface were recognized, while P. molenkampi eggs showed a smooth eggshell. We also evaluated the sensitivity and specificity of the method by training investigators to differentiate surface textures. After training, the investigators were randomly tested with 10 slides containing fluke eggs. The sensitivity and specificity were 95% and 95%, respectively.

Prevalence of Blastocystis hominis infection in asymptomatic individuals from Bangkok, Thailand.

Fresh stool examination was performed from 2,230 participants who enrolled in annual check-up programs of the Faculty of Medical Technology, Mahidol University in 1999-2000 and 2004. In this study, Blastocystis hominis infection was diagnosed by culturing in Jones' media. A total of 21% of fecal specimens (in 1999-2000) and 13.7% (in 2004) were positive for B. hominis. The vacuolated form was the predominant form found in culture solution after 48 hours of incubation. The distribution of infection was highest between the ages of 21-30 years (p<0.05). There was no significant difference in infection between male and female groups. Other parasites, eg Giardia lamblia, Entamoeba histolytica, Entamoeba coli, Endolimax nana, Trichomonas hominis, Strongyloides stercoralis, Opisthorchis viverrini and Taenia species, were also found by fresh stool examination.

Comparison of physiological, cytopathogenic and immunological properties between two environmental isolates of Acanthamoeba spp.

The aim of this study was to determine whether pathogenic and less-pathogenic isolates of environmental Acanthamoeba exhibit differences in adhesion to human erythrocytes. Based on physiological properties of temperature, tolerance, and rapid growth, Acanthamoeba were divided into pathogenic and less-pathogenic isolates. Acanthamoeba were tested for their ability to produce cytopathic effects (CPE) using two human cell lines, HEp-2 and KB cells. Both ameba isolates caused CPE to both cell lines with the same pattern without significant difference. Human erythrocytes from 20 healthy volunteers were used to study the erythrocyte reactivity of Acanthamoeba by co-incubation with trophozoites. The pathogenic Acanthamoeba exhibited significantly higher erythrocyte adhesion as compared to the less-pathogens (p<0.05). Erythrocyte activity occurred in the presence of plasma in all blood samples, suggesting the role of plasmatic components and contact-dependent mechanisms to produce host cell cytotoxicity. The present results showed correlation between the physiological properties and erythrocyte reactivity of Acanthamoeba.