Leptospirosis Raising Health Concern Among Companion Animal Owners

While foot and mouth and mad cow diseases have dominated news headlines in recent months, another disease is raising health concern among owners of companion animals across the country, according to a Kansas State University veterinarian.

Leptospirosis is a bacterial infection that can infect almost any species of animal -- dogs, horses, cows, pigs, etc. According to Dr. Kenneth Harkin, an assistant professor of clinical sciences in the College of Veterinary Medicine, the disease is rarely seen in cats. Leptospirosis can cause an array of clinical signs. The severity of the disease can vary widely; however, leptospirosis has the potential to be severe and even fatal.

The disease is caused by Leptospirosis spp., a spirochete bacteria related to the bacteria that causes Lyme disease and syphilis. There are more than 300 pathogenic varieties (serovars), worldwide. Historically, in the United States, two varieties -- canicola and icterohaemorrhagiae -- were primarily responsible for the disease in dogs. The incidence of infection from these two has declined over the past 30 years, most likely due in large measure to vaccination. The increase in cases most recently has been due primarily to the varieties pomona and grippotyphosa. Until recently no vaccine for these varieties was available.

Leptospira varieties have what are termed maintenance hosts and incidental hosts. Maintenance hosts are those animal species which serve as a reservoir for the Leptospira organism, and in which transmission is very efficient. Incidental hosts include those species of animals that do not act as reservoirs, but that can be infected by the organism. The organism replicates in the kidneys of maintenance hosts and is shed in the urine. In warm damp environments the organism can survive for months in water or soil. Transmission can occur to the new host, either maintenance or incidental, by coming in contact with contaminated water, soil or the carcass of an infected animal.

In dogs, Harkin said there are various symptoms; however, the vast majority of dogs have a sudden onset of vomiting, which may be proceeded by muscle or joint pain or stiffness. Pet owners may mistake this early stage as arthritis and treat the dog with aspirin or another nonsteroidal anti-inflammatory drug.

A less frequent symptom seen in dogs is excessive thirst and urination. Harkin said pet owners are at risk because the dog drinks and urinates so much that they may do so in the house, exposing the owner to the disease.

"There are a few other odd-ball things that can be seen with leptospirosis such as respiratory compromise and pancreaitis," Harkin said. "But the most common symptoms are vomiting and those associated with kidney failure."

If caught early, Harkin said treatment is usually effective and the survival rate is good. However, time is of the essence.

"If you let it go for three or five days, treat it with the wrong antibiotic or with inappropriate fluid therapy, it can create irreversible renal failure," Harkin said.

Humans are also at risk for contracting leptospirosis. Symptoms can be relatively mild and include flu-like symptoms, ocular pain, redness of the eyes, nasal discharge, fever, or muscle and joint pain; however, it can progress to more severe kidney and liver failure. Harkin likens contracting the disease to being "hit by a truck."

"I've actually talked to people who have said they can remember not just the day they got sick but probably the hour and the minute," Harkin said. "It hits you that hard and fast."

According to Harkin, there is a "bit of contention" as to whether the disease is re-emerging or that veterinarians are recognizing it more.

"I think it might be a combination of both," Harkin said. "Veterinarians are a little bit more educated about leptospirosis and making more of an effort to diagnosis it."