Diagnosis of the pinworm Syphacia muris in the Wistar rat Rattus norvegicus.

This study aimed to compare three qualitative parasitological methods for the diagnosis of Syphacia muris infection in 30 Wistar rats (Rattus norvegicus) infected naturally. Methods of spontaneous sedimentation (Hoffman, Pons and Janer, or HPJ) and spontaneous flotation (Willis) for faecal samples and a method of taping (Graham) were performed and compared. The Graham and Willis methods were more sensitive than the HPJ method (P< 0.05). The Graham method was able to detect S. muris eggs in 100% of the samples. Eggs were detected in 83% and 60% of the samples using the Willis and HPJ methods, respectively. Method choice is important for screening for parasites of rats kept under laboratory conditions, as accurate diagnosis helps prevent future environmental contamination and infection. We concluded that the Graham method was the most efficient of those tested in this study for detection of S. muris infection in rats. This method is also rapid, inexpensive and practical, and should be implemented as a necessary measure for infection control.

Specific IgG and immune complex responses to parthenogenetic females and eggs of nematode Strongyloides venezuelensis for the diagnosis of immunosuppression in infected rats.

In the present study, antigens from parthenogenetic females and eggs of Strongyloides venezuelensis, or anti-parthenogenetic-female and anti-egg antigens were used to detect specific IgG and immune complex responses, respectively. Serum samples from experimentally infected immunocompetent and immunosuppressed rats were analysed on days 5, 8, 13 and 21 post-infection (dpi). An enzyme-linked immunosorbent assay (ELISA) was performed using alkaline parasite extract for specific IgG detection, and anti-parthenogenetic-female or anti-egg antigens for immune complex detection. The data were analysed using analysis of variance (ANOVA), followed by a Bonferroni test. When parthenogenetic female or egg extracts were used as antigens, specific IgGs were not detected in either immunocompetent or immunosuppressed rats. When anti-parthenogenetic-female or anti-S. venezuelensis-eggs were used, immune complexes were detected for the duration of the infection in immunosuppressed animals and were only detected between 5 and 13 dpi in immunocompetent animals. The duration of infection was not significantly different between the immunocompetent and immunosuppressed groups when anti-parthenogenetic-female or anti-S. venezuelensis-eggs were used. Parthenogenetic female extracts yielded significant differences between antibody and immune complex responses in immunocompetent rats from 5 to 13 dpi, but only on day 5 dpi in immunosuppressed rats. Exposure to S. venezuelensis egg extract yielded significant differences in both antibody and immune complex detection between immunocompetent and immunosuppressed rats for the duration of the infection. In conclusion, ELISA using alternative antigens may be a successful strategy for identifying immune complexes in serum samples and diagnosing active strongyloidiasis, particularly under conditions of immunosuppression.