Borrelia burgdorferi infection in Wisconsin horses and cows.

The research investigates the prevalence of the bacteria Borrelia burgdorferi, which is associated with Lyme disease, in horses and cows in Wisconsin and explores its potential impact on these animals and transmission lines with humans and ticks.

Introduction and Methodology

• The study was conducted on horses and cows in Wisconsin suspected to be infected with Borrelia burgdorferi, the bacteria causing Lyme disease, which is transmitted through ticks.
• Various samples (blood, milk, colostrum, and synovial fluid) were submitted by practicing veterinarians and were screened for the presence of B. burgdorferi antibodies using a procedure known as Immunofluorescence.
• In addition, these samples were cultured to check for the presence of B. burgdorferi.
• The research team also maintained a record of the clinical symptoms observed in the detected antibody-positive animals, the date of sample collection, and the location of the animal by county.

Findings

• The results showed that out of the samples tested for antibodies, there were significant positive cases in both cow sera and horse sera.
• Different types of samples, like cow synovial fluids, horse synovial fluids, cow colostrums, were also tested where a few cases showed antibodies. However, no antibodies were detected in cow milk samples.
• When cultured, certain samples like cow blood, horse bloods, cow synovial fluids, colostrum and cow urine showed the presence of B. burgdorferi, indicating an infection.
• The study revealed that infection was most common in October and May, a month after ticks typically emerge.

Clinical Signs and Role in Disease Transmission

• Antibody-positive cows and horses frequently displayed symptoms like lameness, swollen joints, stiffness, laminitis (a severe hoof condition), abortions, and fevers.
• However, not all antibody-positive animals showed clinical signs, suggesting that some animals could be carriers without displaying symptoms, this poses a risk of undetected spread of the infection.
• As B. burgdorferi could be isolated from blood, synovial fluid, colostrum, and urine samples, these animals might play a role in transmission, possibly providing an infected blood meal for ticks or bringing the bacteria into direct contact with humans, raising public health concerns.

Conclusion

• These findings reveal that B. burgdorferi infection occurs in horses and cows and can cause clinical illness in some, but not all animals, highlighting the need for vigilance in disease surveillance and potentially, preventive measures.