Detection of Trichinella spiralis DNA in mouse faeces during the early stage of infection.

Trichinella spiralis is an etiological agent of trichinellosis, a parasitic disease present worldwide, affecting both animals and humans. The infection starts from the intestinal stage which usually lasts a few weeks and develops into the muscle phase when larvae enter the muscle cells and create a nurse cell-larva-complex. In animals, the infection is asymptomatic even if a high number of larvae is ingested. The aim of this work was to develop a sensitive test to monitor the early phase of trichinellosis in laboratory animals. T. spiralis DNA presence was assayed in faeces of mice during the first 21 days of experimental infection. The target gene fragment of the mitochondrial ATP6 synthase F0 subunit was amplified by PCR from faecal samples of mice infected with 50, 250 or 500 larvae per mouse (lpm). Trichinella DNA was detected in 45% (116) of the examined faecal samples from days 1 to 21 post infection (p.i.). The time of appearance of the parasite DNA in the faeces and the percentage of PCR positive results were dose dependent. In collective samples consisting of faeces from 3 mice average 80%, 83% and 90% of PCR positive results were obtained for 50, 250 and 500 lpm doses, respectively, throughout 21 days of the observation period. In individual mice faeces DNA was detected on days 2-19 and 9-18 p.i. for 250 lpm and 50 lpm doses, respectively. For both infective doses the highest probability of DNA detection was on day 11 p.i. Since the developed test is simple and non-invasive, it can be useful for monitoring the intestinal phase of Trichinella sp. infection in laboratory animals.