title: A technique for skin application of exact doses of Nippostrongylus brasiliensis to rats.
abstract: Conventional methods for percutaneous infection of rats using third-stage juveniles of Nippostrongylus brasiliensis which have been artificially stimulated to exsheath lead to highly variable, and relatively poor, establishment in the intestine. A new system has been developed in which larvae applied to the skin still remain partially sheathed, as they would be in nature. Cultures of the freeliving stages of the parasite contain an annulus of clear, colourless polythene film to which some of the third-stage juveniles attach. Rats are infected with an individually counted, exact dose applied to the skin on polythene. Using this technique ('EDT20Nb'), consistently high values for the mean proportion of the dose that becomes established (pf) have been obtained, along with a variance well below the normally accepted level (pf = 0.784 +/- 0.015 from a total of 73 rats in 12 separate assays). In particular, the added component of variance between assays in this study was insignificant, so that the probability of quantitative agreement in replicate experiments based on the method is high. It is recommended for an experimental design in which small numbers of parasites can be used.
authors.affiliation: University of Edinburgh, Department of Zoology, Scotland, UK.
authors.forename: N R
authors.initials: NR
authors.lastname: Tindall
authors.forename: P A
authors.initials: PA
authors.lastname: Wilson
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D005260:Female; D007411:Intestinal Diseases, Parasitic / Q000469:parasitology*; D008297:Male; D009349:Nematode Infections / Q000469:parasitology*; D009559:Nippostrongylus / Q000254:growth & development*; D051381:Rats