Campylobacter spp

From Cow
Bulls are usually infected by mating with infected cows
Placental chorionitis in a cow infected with Campylobacter spp
Bacterin for use in healthy female cattle as an aid in the control of campylobacteriosis

Camyplobacter spp is a bacterial infection that causes campylobacteriosis (formerly known as vibriosis), a venereal disease in cattle worldwide.

This disease is characterised by early embryonic death, infertility, prolonged calving season, reduced weaning rates and abortions[1].

Cause

Campylobacter spp is a motile, gram-negative, curved or spiral, polar flagellated, microaerophilic bacteria. A number of species have been identified:

  • Campylobacter fetus venerealis[2]
  • C. fetus fetus[3]

C. fetus is transmitted venereally as well as by contaminated instruments, bedding, or by artificial insemination using contaminated semen. Individual bulls vary in their susceptibility to infection; some become permanent carriers, while others appear to be resistant to infection. In young bulls under 3 years of age, infection tends to be transient. In older bulls, the deeper crypts may provide the proper microaerophilic environment required for the establishment of chronic infections[4].

In cows, the duration of the carrier state is also variable; some clear the infection rapidly, while others can carry C. fetus for more than 2 years. Although most of the genital tract may be free of infection when a cow eventually conceives, the vagina may remain chronically infected through pregnancy.

Clinical signs

Clinical signs of infection with Campylobacter spp include fetal loss, abortions, irregular oestrus cycles, repeat breeding and reduced fertility in cows. Supportive evidence by culture of C. fetus fetus in submitted tissue samples[5].

C. fetus sub venerealis persistently colonize the lower genital tract of bulls but usually do not cause either major clinical signs or inflammation.

in aborted foetuses, C. fetus sub fetus causes neutrophilic bronchopneumonia and interstitial pneumonia. Other commonly observed lesions include non-suppurative interstitial enteritis, hepatitis, pericarditis, myositis, myocarditis, and meningitis[6].

Diagnosis

Diagnosis is based on historical evidence of breeding problems, supported with diagnostic tests that confirm infection. ELISA and PCR tests are available for diagnostic use on vaginal mucus[7]. Field evaluation of the PCR assays reveal a sensitivity and specificity of 85.7% and 99%, respectively[8].

Vaginal cultures taken immediately after abortion or infection can be used for diagnosis, but C. fetus is labile and requires special techniques for isolation.

Preputial cavity and fornix swabs may isolate the bacterium which is then examined using a fluorescent antibody test and culture. Bulls should be sampled twice, approximately 1 week apart.

Treatment

For practical reasons, cows are not usually treated with antibiotics for genital campylobacteriosis, but sensitivity to spectinomycin, gentamicin, streptomycin and penicillin has been noted[9].

Prophylactic injections with campylobacter bacterin is recommended for herd control of genital campylobacteriosis. The bacterin contains inactivated cultures of C. fetus sub fetus. Both infected cows and cows at risk should be vaccinated. In routine use, the vaccine should be given once, about 4 weeks before breeding starts. Bulls are usually vaccinated as well but are given twice the dose used for cows, 3 weeks apart. The infection can also be eliminated in bulls by treatment with streptomycin (20 mg/kg, SC, 1–2 treatments) together with 5 g of streptomycin in an oil-based suspension applied to the penis for 3 consecutive days.

Although the male genital immune responses to T. foetus and C. fetus subspecies venerealis are inefficient in clearing infection, systemic immunization with T. foetus and C. fetus subspecies venerealis antigens does prevent or eliminate these infections with induction of IgG antibodies in genital secretions and serum[10].

When practical, artificial insemination is an excellent way to prevent or control genital campylobacteriosis.


References

  1. Jimenez DF et al (2011) Factors associated with infection by Campylobacter fetus in beef herds in the Province of Buenos Aires, Argentina. Prev Vet Med 101(3-4):157-162
  2. Stynen AP et al (2011) Complete genome sequence of type strain Campylobacter fetus subsp. venerealis NCTC 10354T. J Bacteriol 193(20):5871-5872
  3. Mendoza-Ibarra JA et al (2011) High prevalence of Tritrichomonas foetus infection in Asturiana de la Montaña beef cattle kept in extensive conditions in Northern Spain. Vet J 193(1):146-151
  4. Merck Vet Manual
  5. Yang N et al (2012) Survey of nine abortifacient infectious agents in aborted bovine fetuses from dairy farms in Beijing, China, by PCR. Acta Vet Hung 60(1):83-92
  6. Morrell EL et al(2011) Histopathological, immunohistochemical, lectinhistochemical and molecular findings in spontaneous bovine abortions by Campylobacter fetus. Reprod Domest Anim 46(2):309-315
  7. Tramuta C et al (2011) Development of a set of multiplex standard polymerase chain reaction assays for the identification of infectious agents from aborted bovine clinical samples. J Vet Diagn Invest 23(4):657-664
  8. Schmidt T et al (2010) Evaluation of PCR assays for the detection of Campylobacter fetus in bovine preputial scrapings and the identification of subspecies in South African field isolates. J S Afr Vet Assoc 81(2):87-92
  9. Hänel I et al (2011) Antimicrobial susceptibility testing of German Campylobacter fetus subsp. venerealis isolates by agar disk diffusion method. Berl Munch Tierarztl Wochenschr 124(5-6):198-202
  10. Cobo ER et al (2011) Immunity to infections in the lower genital tract of bulls. J Reprod Immunol 89(1):55-61