Leptospirosis in Domestic Animals

Leptospirosis is one of the most widespread diseases of livestock and is caused by over 250 varieties of Leptospira bacteria. Out of these variations, only a small number has been found in domestic animals. The bacteria are spread by contact of skin and mucous membranes with contaminated products. Infected animals contribute to further spreading of the disease by actively shedding bacteria.

Signs of leptospirosis in domestic animals are quite variable and can range from total absence of signs through bizarre clinical manifestations to severe disease. Since the rate of infection is extremely variable, the disease may affect only a few animals, or it can be a major herd problem. Often asymptomatic herd leptospirosis is discovered following human contact and infection.

Most cases of leptospirosis - when signs do develop - start with a rise in temperature to between 103 °F and 106 °F and may last 1-7 days. Fever is usually accompanied by loss of appetite, dull appearance and a drop in milk production. In more severe cases, bloody urine and anemia can be observed. Reproduction problems (abortions or the birth of retarded calves) may occur, but they are not directly related to the severity of the original infection. Loss of newborn animals always indicates the need to check for leptospirosis.

Due to diversified signs of leptospirosis, clinical diagnosis of the disease in domestic animals usually maintained as individuals, such as dogs, cats and horses, is even more complicated than in herd animals, where surveillance is easier although difficult to interpret. Definite diagnosis always requires identification of specific antibodies or antigens1. Leptospirosis in domestic animals leads to major economic losses valued in hundreds of millions of dollars annually. Realizing the potential economic hazards of leptospirosis, many countries are expanding successful vaccination programs designsed to prevent clinical disease in their livestock.1

Inactivated polyvalent vaccines containing different Leptospiras (e.g. grippotyphosa, hardjo, icterohaemorrhagia, canicola, pomona) are commercially available for preventing abortions and stillborns in livestock and pets. Most of them have been combined with components against other pathogens such as E. rhusiopathiae, parvovirus, Campylobacter, bovien rhinotracheitis virus, bovine diarrhea virus and bovine respiratory syncytial virus.2 Certain occupational groups such as farmers, sewer workers and meat workers have special risks of acquiring the disease.

References

  1. Handbook of Zoonoses: section A. Bacterial, rickettsial, chlamydial, and mycotic. George W. Beran, James H. Steele
  2. Novel vaccination strategies. Stefan H. E. Kaufmann