Plagiorchis elegans (Trematoda) induces immune response in an incompatible snail host Biomphalaria glabrata (Pulmonata: Planorbidae).

Plagiorchis elegans has been shown to decrease the fecundity and survivorship of the incompatible snail host Biomphalaria glabrata. Furthermore, a prior infection with P. elegans was shown to render the snails resistant to the compatible parasite Schistosoma mansoni. Here, we test the hypothesis that infection with P. elegans stimulates the immune system of B. glabrata. Our findings indicate that infection by P. elegans significantly increased the number of free hemocytes in the hemolymph of B. glabrata by an average of ~60%. Furthermore, this immuno-stimulated state lasted from the first day post-infection (PI) to some time between 7 and 21 days PI. This is one of the few reported examples of a parasite stimulating the immune response of an incompatible host.

Fetal fibronectin: a method for detecting the presence of amniotic fluid.

OBJECTIVE: To determine whether fetal fibronectin is a sensitive test for the detection of amniotic fluid (AF) in women with rupture of the membranes. METHODS: In a multicenter clinical trial, pooling, ferning, and nitrazine tests were compared with fetal fibronectin in 339 women at term (study group) with a clinical history of rupture of the membranes and in 67 women at term receiving routine prenatal care (controls). Ruptured membranes was diagnosed if any two of the standard tests were positive. Fetal fibronectin in the cervicovaginal secretions was determined using a qualitative enzyme-linked immunosorbent assay test. Fetal fibronectin was considered positive at 50 ng/mL. RESULTS: The sensitivity of fetal fibronectin in the women with ruptured membranes was 98.2%. No controls had ruptured membranes based on standard test results, but 13 women had fetal fibronectin present. The mean (+/- standard error) interval between sampling and delivery was significantly less in the women positive for fetal fibronectin (169.3 +/- 45.8 hours) than in those with no detectable fetal fibronectin (333.4 +/- 29.0 hours). CONCLUSION: Fetal fibronectin is a sensitive test for detection of AF in the vagina and compares favorably to standard tests. Its low specificity suggests that the assay may detect an alteration in membrane integrity. In addition, in patients without rupture of the membranes, the interval between sampling and delivery is significantly shorter if fetal fibronectin is present. We speculate that the presence of fetal fibronectin in cervicovaginal secretions may be a marker for impending labor in gravidas without gross rupture of the membranes.