CHLAMYDIAL INFECTION IN CATTLE WITH SPECIAL REFERENCE TO FERTILITY

Chlamydiae are small, obligate intracellular microorganisms with a typical development life cycle. Out of 9 mammalian Chlamydia psittaci serotypes only the serotypes l and ll have pathologic potential for cattle. A 90 Kd protein may be associated with virulence of chlamydial strains. C. psittaci is the primary cause of many different clinical syndromes. A defintive diagnosis should involve laboratory methods. Demonstration of chlamydial antigen is more useful than serological CF-methods, because this test is relatively insensitive particularly in detecting local mucosal infections. A scheme for definitive and presumptive diagnosis is given. Vaccines have been studied for prevention of abortion. But there are only a few investigations to demonstrate the efficacy of vaccination. The same situation exists concerning the use of several antibiotics. It is important to keep in mind that cattle will become healthy but chlamydial agents may remain after treatment or vaccination.