Early detection of Trichinella spiralis DNA in the feces of experimentally infected mice by using PCR

- T. spiralis DNA in feces of mice infected with 100 or 300 larvae was assayed by PCR.
- The sensitivity of PCR was 0.016 larvae in feces.
- No cross-reactivity was observed with the DNA of other intestinal helminths.
- T. spiralis DNA was detected in 100% (12/12) of the feces of infected mice at 3 hpi.
- Detection of fecal DNA might be useful for early diagnosis of Trichinella infection.

The aim of this study was to detect Trichinella spiralis DNA in mouse feces during the early stages of infection using PCR. The target gene fragment, a 1.6 kb repetitive sequence of T. spiralis genome, was amplified by PCR from feces of mice infected with 100 or 300 larvae at 3-24 h post infection (hpi) and 2-28 dpi. The sensitivity of PCR was 0.016 larvae in feces. The primers used were highly specific for T. spiralis. No cross-reactivity was observed with the DNA of other intestinal helminths. T. spiralis DNA was detected in 100% (12/12) of feces of mice infected with 100 or 300 larvae as early as 3 hpi, with the peak detection lasting to 12-24 hpi, and then fluctuating before declining gradually. By 28 dpi, the detection rate of T. spiralis DNA in feces of the two groups of infected mice decreased to 8.33% and 25%, respectively. PCR detection of T. spiralis DNA in feces is simple and specific; it might be useful for the early diagnosis of Trichinella infection.

PCR detection of Trichinella spiralis DNA in fecal samples of mice infected with 300 muscle larvae at 3 h post infection (A) and 20 days post infection (B).106