Leptospirosis

 Barb Meining, DVM

 Leptospirosis is a type of bacteria, a spirochete, with world-wide distribution.  It affects dogs, cats, pigs, horses, raccoons, rodents and more.  There are wild animals and even some livestock that act as reservoir hosts which may shed the organism for years, while not showing symptoms.  In Michigan, it is more prevalent in the southern half of the lower peninsula.

 Lepto may be spread via direct contact with the urine of an affected animal.  It is not aerosolized at all, but also may be spread through venereal contact, through a bite wound, or eating tissue of affected animals.  Indirectly it may be spread via contact with contaminated soil, water or food.  The organism may survive months in water or moist soil or leaf litter.

 Symptoms in dogs may be varied, including anorexia, vomiting, dehydration, jaundice, drinking a lot, or just not doing right .  Signs usually are a result of liver or kidney disease.  Lepto may be fatal if not caught and treated early.

 Diagnosis involves checking lepto titers (a simple blood test) on dogs that are symptomatic.  Unfortunately, titers can be negative early on in the disease, so if there is a high suspicion and an animal tests negative, retest!  If an animal has been recently vaccinated, their titers will be high.  You can differentiate active lepto from a high vaccine titer by rechecking the titer in 2 weeks.  Active disease will show a titer that’s rising.

 Treatment involves supportive care and antibiotics.  If the animal is not eating or dehydrated, IV fluids are often necessary.  Antibiotics are done in two phases.  During the acute (1^st) phase, dogs are put on penicillin for 2 weeks.  After that, they are put on doxycycline for another 2—6 weeks to hopefully eliminate the carrier state.

 Leptospirosis is a zoonotic disease (contagious to humans from animals).  According to the CDC, there are 50-100 human cases per year, and the primary source of human infection is the canine!  Humans develop lepto through contact with affected urine or blood.  Fortunately, common household disinfectants will kill lepto, even antibacterial dishsoap.  Outside, it does not survive freezing or drying, but may live in leaf litter or moist soil, eg riverbanks.  Cats can develop lepto, but appear to be resistant to it.  There is no feline lepto vaccine.

 Prevention involves vaccinating our dogs.  Prior to lepto vaccines in the 60’s, the strains of L. icterohemorragiae and L. canicola were quite prevalent.  Then the vaccine against these 2 serovars came out.  Nowadays, these are the least common strains we see.  For the last few years, newer vaccines have emerged that protect against the original 2 serovars (ictero and canicola) as well as L. grippotyphosa and L. pomona.  Unfortunately, there are generally 6 serovars of lepto that may affect dogs.   At this time, there is not a vaccine for  L. bratislava L. hardjo.  There is no cross protection against serovars that are not vaccinated for.  At MSU, the primary serovar they are seeing is grippo (75-80% of positive submissions).  Most of the rest are bratislava.

 However, the lepto vaccine did come with controversy in that it had a fairly high level of adverse reactions.  Smaller breeds and very young puppies seemed to be at higher risk to vaccine reactions.  Today’s vaccines have newer technology so that they minimize vaccine reactions, but a dog may still react to ANY vaccine given.  I recommend giving puppies under 12 weeks a DA2PP vaccine (without lepto), then give DA2PPL4 vaccines for the final 2 vaccines in their puppy series.  If you have a breed that is susceptible to reaction, pretreat with benadryl.  The lepto vaccine needs to be boosted annually.