Impaired intestinal electrolyte transport in rats infested with the common parasite Syphacia muris

An incidentally discovered infestation with the nematode Syphacia muris of cecum and colon in spontaneously hypertensive (SHR) and normotensive control (WKY) rats was investigated over a two-year period. Infestation rates in WKY were higher than in SHR, while clinical signs as well as histological changes of colonic tissues were absent in both strains. In vivo net water absorption (microliter/hr/cm2) in control worm-free SHR turned into secretion in infested rats, ie, from 74.2 +/- 23.2 to -7.5 +/- 35.0 (P less than 0.001); this corresponded with a decrease in net absorption (mumol/hr/cm2) of Na from 18.5 +/- 2.4 to 9.3 +/- 4.3 (P less than 0.001) and of Cl from 14.0 +/- 3.2 to 3.2 +/- 5.7 (P less than 0.001). In WKY, net water absorption decreased from 112.2 +/- 23.2 to 48.0 +/- 25.1 (P less than 0.001) and Na and Cl absorption from 22.3 +/- 3.1 to 16.0 +/- 4.2 (P less than 0.005) and from 19.4 +/- 2.7 to 10.9 +/- 4.7 (P less than 0.005), respectively. Antihelminthic treatment with 0.007% pyrvinium pamoate in the ration (four weeks on, six months off) eradicated Syphacia muris in both rat strains. Body weight gain of young rats on normal and pyrvinium pamoate-substituted diet studied over 18 months was similar, indicating a good tolerance of the treatment. It is concluded that results obtained during comparative intestinal transport studies between SHR and WKY may not only be impaired but also significantly distorted by Syphacia muris infestation as SHR appear to be more susceptible to effects induced by this common parasite than WKY.