Veterinary Alert: Leptospirosis Outbreak in Dogs in Maricopa County

Courtesy of the AZ Veterinary Medical Association (edited) - Thursday, November 10, 2016

Some Maricopa County veterinarians are seeing an increase in the number of cases of canine leptospirosis. At least 20 laboratory positive dogs have been reported since the beginning of 2016. Most of the cases have been associated with two clusters including one reported in February involving show dogs and a more recent one involving a boarding facility. Clinical presentations have ranged from asymptomatic infections and conjunctivitis to kidney failure. Until recently, canine leptospirosis cases in Arizona were considered to be rare and sporadic and had not occurred in outbreak settings.

Leptospirosis is caused by any one of >250 Leptospira interrogans serovars and is transmitted through direct contact with urine, water, soil, or contaminated fomites. The bacteria can survive in water or moist soil for weeks to months, and persistently infected dogs can shed the bacteria in urine for months to years. Infection can be asymptomatic or severe, and range from acute to chronic infection. Signs and symptoms in dogs include fever and depression, as well as kidney involvement with polydipsia (excessive thirst and fluid intake), polyuria (increase urine output), oliguria (decreased urine output), or anuria (no urine output). Liver failure is also common with some serovars.

While the serovars that are often diagnosed in dogs (e.g. Canicola, Grippotyphosa, Pomona, etc.) rarely cause illness in humans, people in close contact with infected pets are at risk. Prevention precautions should be taken by veterinary staff and pet owners to reduce transmission risk. This includes: using personal protective equipment (PPE) when handling infected animals, routine disinfection of urine contaminated areas, and proper disposal of potentially infectious bodily fluids

In humans, leptospirosis infection can cause a wide spectrum of illness ranging from asymptomatic or mild disease to kidney failure, aseptic meningitis, or other severe life-threatening syndromes.

In light of recent trends, veterinarians might want to recommend leptospirosis vaccination for dogs that may be at increased risk for exposure (see below). Choose a vaccine that provides protection against Serovars Canicola, Grippotyphosa, and Pomona.

Dogs at increased risk may include:

  • Outdoor dogs that engage in hiking, wading, and swimming in natural waters
  • Dogs on ranches and farms where there is contact with other animals and animal urine
  • Hunting dogs
  • Dogs that are frequently exposed to areas of flooding
  • Dogs that reside in rural areas or fringe areas where there is potential contact to wildlife or animal urine
  • Dogs that have frequent exposure to other dogs and dog urine such as at dog shows, dog parks, pet boarding facilities, etc.
  • Dogs that travel widely and have contact with other dogs and/or other animals

Vaccine reactions (including anaphylaxis), though uncommon, have been linked to the Leptospira vaccine. Owners should watch vaccinated animals for 24 hours following vaccine and note any adverse effects – including swelling and redness at the vaccine site, lameness in the leg proximal to the vaccination site, or depressed appetite. If owners are concerned about an adverse reaction, it is possible to pre-treat with diphenhydramine.

**Update – as of 2/1/17:

The Arizona State Veterinarian’s office reports that they are receiving almost daily reports of positive Leptospirosis cases in the state of Arizona, many in Maricopa county. Though they did not have specific numbers of Maricopa County cases, they are advising veterinarians in our county to vaccinate dogs at risk.

Make and appointment at Tatum Point Animal Hospital to get your dog vaccinated for Lepto. (2 vaccines, 2-4 wks apart with exam, then yearly)

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