Diagnostic complications from "fecal" trichomonads

Abstract

Routine methods for the culture of Tritrichomonas foetus cannot differentiate between it and faecal/enteric trichomonads. Faecal/enteric trichomonads can contaminate the sheath of bulls and result in their being classed as infected with trichomonads. Current Utah regulations require the slaughter of all trichomonad-positive bulls. The presence of faecal/enteric trichomonads is documented, but the extent in Utah is unknown. Culture of faecal samples from 55 bull calves in 11 herds was conducted to recover trichomonads. The faecal samples were collected on 29 October 2002. Typical positive trichomonad cultures were found in 23 of 55 faecal samples (42%), and in all of the 11 herds (100%). Three samples with the heaviest growth of trichomonads were sent to a second laboratory for PCR and staining diagnostics. All 3 isolates were negative using T. foetus-specific PCR primers. They were also observed to have 4 anterior flagella and were classified as Tetratrichomonas species. These results indicate that faecal trichomonads are common in cattle of Utah and southern Idaho. There is no evidence that this type of trichomonad is pathogenic. Regulations need to allow for further specific identification of trichomonad organisms from young bulls, and especially for valuable bulls.