Tritrichomonas fetus PCR - cattle

Tritrichomonas fetus PCR – cattle

Species: Bovine

Specimen: Preputial scraping/washing and vaginal mucus. These samples can be collected with a scraping device called a ‘Tricamper’ (contact Awanui Veterinary for supplies)

Container: ‘Tricamper’ end clipped off into a sterile pottle or plain tube

Collection protocol: Use the ’Tricamper‘ to scrape the preputial lining or the vagina

Special handling/shipping requirements: Ship chilled

General information about the disease:

Tritrichomonas fetus is a flagellate, pyriform protozoan parasite that can cause infertility in cattle.

T. fetus resides in the preputial cavity of bulls, with some concentration in the fornix and around the glans penis, with little or no clinical signs. Chronically infected bulls show no gross lesions. For bulls older than 3–4 years, spontaneous recovery rarely occurs, resulting in a permanent source of infection in herds. In bulls under 3–4 years old, infection may be transient.

In the infected cow, the initial lesion is a vaginitis and animals may exhibit irregular oestrous cycles. Cows usually clear their infection and generally become immune, at least for that breeding season. If infected cows become pregnant the organism may invade the cervix and uterus with various outcomes including placentitis leading to early abortion (1–16 weeks), uterine discharge, and pyometra. Not all infections result in abortion and a normal calf is born. Transmission of infection occurs by coitus, by artificial insemination, or by gynaecological examination of cows. Bulls are the main reservoir of the disease as they tend to be long-term carriers, whereas most cows clear the infection spontaneously. For these reasons samples from bulls are usually preferred for diagnosing and controlling the disease in herds.

General information about when this test is indicated:

PCR provides a very sensitive and specific method for detection of T. fetus in clinical samples. The organisms do not need to be viable and it will detect very lower numbers. Currently this method is not approved for export testing.  This is a disease of low prevalence in New Zealand.

Comparison with other related tests:

The traditional method for diagnosis is culture and microscopic examination but the sensitivity of this method is relatively poor given as it depends on a relatively uncontaminated sample being collected in a manner that maximises the number of organisms present and for the sample to reach the lab in a viable state for culture.