LEPTOSPIROSIS

Causative Agent(s)

Pathogenic Leptospira are classified into one species of Leptospira interrogans containing over 212 serovars arranged into 23 serogroups. Serovars Hardjo and Pomona are the main pathogens affecting cattle. Occasionally, they are affected by serovars Grippotyphosa, Bratislava, Ictaerohaemorragiae, and Canicola.

Clinical Presentation and Epidemiology

Acute leptospirosis by L. Pomona: calves less than 1 month are most susceptible. There is high fever, anorexia, petechiation of mucosae, depression, and acute haemolytic anaemia with haemoglobinuria, jaundice, pallor of mucosae. Because of the anaemia there is tachycardia, loud heart sound, and dyspnoea. There may be abortion in adult cattle; marked drop in milk production or agalactia, secretion is red coloured, udder is limp and soft. There may be severe lameness due to synovitis. The chronic cases are mild and may be restricted to abortion. Abortion storms can occur in a group of cattle, and usually during the last trimester of pregnancy.

Diagnostic Considerations

Bacterial culture and detection of Leptospira in blood, body fluid, tissue, urine, or aborted foetus is diagnostic. However, the organism is difficult to culture, and most commercial laboratories do not routinely culture for the organism.

Direct microscopy examination of urine using dark field microscopy or FAT is useful test

Management and Treatment

Antibiotics such as tetracycline, oxytetracycline, penicillin, ceftiofur, Penicillin and streptomycin combination are effective

Oxytetracycline 5-10 mg/kg IM, q24h; 20 mg/kg IM; repeat after 2-4 days if depot form long acting (LA)
Cephalosporins can be used such as ceftiofur (1.1-2.2 mg/kg PO x 5-7/7 if other treatments proved abortive. But this can only be done after bacterial culture and sensitivity tests have been thoroughly conducted.