Vaccination programs for reproductive disorders of small ruminants. (Special Issue: Reproductive health management of sheep and goats.)

摘要

Vaccines are available for the control of contagious epididymitis and abortion in small ruminants, although many of them have significant limitations either in efficacy or safety to both the animals vaccinated and to the people handling the vaccine or animals. Shelf-life of vaccines should be extended and improved, so that the vaccine remains effective with longer term storage and ideally without refrigeration, so that use in under-developed rural areas is not restricted (e.g., Brucella melitensis, Toxoplasma gondii). The vaccines should not be dangerous for veterinarians or producers to handle (again as examples, B. melitensis, T. gondii). The vaccines should prevent shedding of the organism, in order to prevent spread of the disease causal agent through the sale of vaccinated but shedding animals (e.g., inactivated killed Chlamydophila abortus vaccines), as well as to prevent possible exposure to people handling those vaccinated animals. Production of vaccines using zoonotic disease agents is problematic and sometime dangerous, which increases regulatory restrictions and reduces availability of those vaccines (e.g., C. abortus, Coxiella burnetii). Development of subunit recombinant DNA vaccines may offer a method to increase access to these important vaccines, as long as they are also effective, prevent shedding and remain cost effective. It is important that these vaccines are brought to international commercial production. As many of these disease agents are zoonotic and prevalent world-wide, improvement in vaccine efficacy and safety is of extreme importance.