B152 - CAPRINE AND OVINE BRUCELLOSIS (EXCLUDING B. OVIS)

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B152 - CAPRINE AND OVINE BRUCELLOSIS (EXCLUDING B. OVIS)

Nature of the disease
Caprine and Ovine Brucellosis groups infection of small ruminants by Brucella melitensis and in a less extent B. abortus. Both are severe zoonosis, B. melitensis is known as the 'Malta' or 'Mediterranean' fever in humans and B. abortus is also known as 'Bang' disease.
Classification
OIE, List B disease
Susceptible species
B. melitensis mostly affects ovine and caprine very contagious to humans, contagious to cattle and less commonly horses and pigs.
B. abortus mainly affects cattle but it can passes to a number of species including small ruminants and less commonly pigs and humans.
Distribution
Ovine and caprine brucellosis is mainly present in the Mediterranean region, it also present in some Asian, African and Central Amercian countries. It is seems top be anecdotic in the Pacific Region, it has not been recorded in French Polynesia since 2000 and in Guam since 1993 and other countries never reported it. 
Clinical signs 
Ovine and caprine brucellosis is characterised by:
  • Late abortions (2months), 
  • Stillbirths,
  • Weak newborns,
  • Placentitis (more common in cows) 
  • Mastitis,
  • Orchitis in males,
  • Lameness and hygroma (more common in goats)
Post-mortem findings 
There is no characteristic lesions.
Differential diagnosis 
In ovine and caprine abortions due to :
Specimens required for diagnosis 
In case of clinic suspicion, Brucella spp. should be isolated from placenta, aborted foetuses, milk, testes or epididymi. Identification of the bacteria is done by microscopic observation of stained preparation. PCR techniques are also available.

For screening purposes the rose bengal plate agglutination and complement fixation tests are used. The serum agglutination test is not considered to be reliable for use in small ruminants. For pooled samples, there are no useful tests such as the milk ring test in cattle.

Allergic skin tests (brucellin allergic skin test ) is also available and can be used as a screening or complementary test in unvaccinated flocks. Results must then be interpreted in relation to the clinical signs, history, and the results of serological or cultural examination.

Transmission   
Animals acquire the disease through oral (ingestion), skin (wound) and sexual route. The main source of infection are milk and milk products and  abortion material.
Risk of introduction   
Ovine brucellosis is more likely to be introduced through importation of infected animals, semen or embryos. However importation of contaminated milk and milk products should be also considered mainly because of the zoonotic risk. Pasteurisation kills the germ.
Control / vaccines  
A vaccine is available and can be used in infected areas. 

The best option for eradication of the disease is testing and removal of positives.

References