Michigan State warns of leptospirosis outbreak around Detroit

Detroit

— Over the past three weeks, more than 20 cases of leptospirosis have been reported in Detroit-area dogs.

The Diagnostic Center for Animal and Population Health (DCPAH) at the Michigan State University College of Veterinary Medicine (MSU) established the leptospirosis diagnosis and identified the specific strain of the infection.

Carole Bolin, DVM, PhD, professor and director of DCPAH, and her team identified the particular strain as Icterohaemorrhiage, which can cause severe disease in humans and animals. It is commonly carried by rats, but can be transmitted dog to dog, or dog to human, according to MSU. Bolin says nine dogs have died or were euthanized as a result of the disease, but she says there may be more. In most of the diagnosed cases, the dogs were not vaccinated against leptospirosis or had an uncertain vaccination history.

Stray dogs are considered at the highest risk for this particular type of leptospirosis, since it is associated with contact with rats, but that’s not the case in this outbreak, Bolin says.

“What is particularly unusual about this outbreak is that the dogs affected are not stray animals, but people’s pets,” says Bolin. “Unfortunately, we expect to see more cases, and this is a very dangerous type of leptospirosis. Many veterinarians have never seen this very severe type of leptospirosis in dogs because it was markedly reduced by vaccination.”

Bolin says this strain of leptospirosis is relatively rare, and can be shed through an infected animal’s urine. Healthy animals can then pick up the leptospira by sniffing the urine or by coming in contact with standing water contaminated by rain and water runoff. The bacteria spreads rapidly in an animal’s blood, usually causing fever, depression, and vomiting, according to MSU. The bacteria also attacks the liver and kidneys, which can lead to organ failure.

“This is a very serious, rapidly progressing type of leptospirosis in dogs. Dogs can appear normal one day and be severely ill the next,” says Bolin. “People can become infected, so this also is a threat to animal owners, caretakers, and veterinarians.”

MSU says leptospirosis is not a new problem around Detroit. In the 1980s, Bolin’s mentor, Dr. Alex Thiermann, conducted studies on the high leptospirosis prevalence in the rat and dog population in Detroit. The culprit-also the same of the current outbreak-resulted in human cases as well as infections in rats and stray dogs. The prevalence dropped significantly after the conditions predisposing to large rat populations were corrected and leptospirosis vaccines became routine for dogs.

But as cases decreased, and because of the potential for adverse reactions to the vaccine, its use diminished and the vaccine is no longer administered to all dogs. Bolin says the new outbreak demonstrates that leptospirosis remains a significant risk for dogs. She recommends veterinarians in the area step up vaccination efforts and educate pet owners about the spread of leptospirosis.