Yesterday, I received a Veterinary Alert from the Arizona Veterinary Medical Association regarding an outbreak of Leptospirosis in dogs in Maricopa County, Arizona. In addition to the outbreak that occurred last February, there has been a second one associated with a boarding facility. The infected dogs showed a diverse array of clinical sings from conjunctivitis to kidney failure. Some dogs showed no signs at all which is especially troubling.
Leptospirosis is a serious disease that affects dogs, cats, horses, swine, sheep, goats, deer, marine mammals and humans. Signs of leptospirosis vary greatly from mild malaise to death. The incubation period is usually 7 days. The most common signs in dogs in the early phase are fever, shivering, lethargy, decreased appetite and muscle tenderness. As the disease progresses, increased thirst and urination, abdominal pain, vomiting, eye disease, diarrhea, joint stiffness, bruising of the skin, coughing and a runny nose are just a few of the symptoms that can occur. The exact symptoms depend upon which organ is affected. Animals with liver involvement become jaundiced (yellow color of the skin). If the nervous system is involved, animals may seizure, have problems walking or suffer neurologic deficits.
Diagnosis of leptospirosis requires special testing to identify the organism. Routine blood work, urinalysis and clotting tests will make it a rule-out but not make the diagnosis. 87-100% of dogs present with elevated creatinine and BUN.
Leptospira bacteria like to live in warm moist environments with alkaline soil. Under these conditions, the bacteria can survive for months. Infections occur through direct exposure to the urine, saliva (bite wounds) or tissues of animals infected with the disease. It can also be contracted indirectly by contact with water, soil, food or bedding that is contaminated with the organism. The leptospires can penetrate mucous membranes and damaged skin. In the February 2016, nine dogs tested positive for this disease in Scottsdale, Arizona. It is thought that heavy storms left standing water that was contaminated by pack rats. Unfortunately, one dog did not respond to treatment and died.
Prevention is the key to dealing with leptospirosis. Thankfully, there are two vaccines available for dogs in the United Sates. One is a bivalent which means it only contains two serovars, icterohaemorrhagiae and canicola. I recommend the other vaccine which contains 4 serovars – canicola, icterohaemorrhagiae, grippotyphosa and pomona. This vaccine is licensed for pups 6 weeks and older. The manufacturer recommends 2 doses of the vaccine given 2-3 weeks apart and then boosted annually.
More information is available at www.ncbi.nlm.nih.gov/pmc/articles/PMC3040842/.
Sources:
-Adams, Laura. Canine Leptospirosis in Arizona, Arizona Veterinary News, Arizona Veterinary Medical Association, March 2016.
-Arizona Veterinary Medical Association, Veterinary Alert: Leptospirosis Outbreak in Dogs in Maricopa County. November 10, 2016.
-Morgan, Rhea. Leptospirosis (Zoonotic), Associate Database, Veterinary Information Network, 1/29/2014, Last updated by Kari Rothrock 1/20/2012.