Publisher Health

Alarm has grown among some New York City dog owners in recent days as reports have circulated about the risks to canine health posed by the city’s legions of rats.

In the Williamsburg section of Brooklyn, a corner of McCarren Park that is used as a dog run was temporarily shut for maintenance after rumors of an outbreak of leptospirosis, a bacterial disease spread by rat urine, lit up social media. The bacteria can fester in puddles and damp spots, and animals can become gravely ill if they contract the disease. It can also sicken humans.

Lincoln Restler, a councilman who represents the area, tweeted last week that his office had received reports that several dogs who had visited the park later died of the disease. The city Health Department said it could not confirm the reports, but said that it was working with the Parks Department to inspect for rat activity in the park. Local veterinarians are supposed to report positive cases of leptospirosis to the Health Department.

“I’m hopeful that the actions taken by the parks and health department will address the conditions we have at McCarren,” Mr. Restler said in an interview.

The accounts led to grave concern from dog owners, and reminders from local veterinarians about the importance of vaccinating dogs that spend a lot of time in parks.

What is leptospirosis?

The disease is caused by bacteria found in the urine of infected rodents and both humans and animals are susceptible to it.

The bacteria thrives in warm, wet environments, and can survive in soil, water and food. It can enter the body through open wounds or mucous membranes, or by drinking infected water.

The bacteria usually surges in the late summer and fall, said Dr. Gabrielle Fadl, a veterinarian at Bond Vet, a local chain. The initial symptoms are fairly nonspecific, including vomiting, fever and lethargy, making it tricky to diagnose an infection quickly.

Symptoms usually begin a week or two after exposure, and can be treated with antibiotics. If left untreated, leptospirosis can cause severe liver and kidney damage, and can be life-threatening.

How prevalent is the disease in New York City?

Reported cases of leptospirosis among people increased fairly dramatically last year, a spike that is believed to be linked to the spike in the rat population. At the same time, reported cases of canine leptospirosis actually dropped.

The city reported 15 cases among people last year, in contrast to an average of three cases a year for the previous 15 years. Health officials said that most cases “had a clear history or risk factor which exposed them to an environment with a severe rat infestation.” At least one of the people who was infected died. Human-to-human transmission is rare, and none of the cases was linked to a dog’s infection.

Among dogs, there were also 15 cases reported last year, down from a high of 29 in 2018. But health officials warned that the drop may be because providers failed to report cases as required. Between 2006 and 2020, a total of 269 cases — anywhere from eight to 29 cases per year — were reported to the Health Department from all five boroughs.

The federal Centers for Disease Control and Prevention notes on its website that the disease has been diagnosed among pets more frequently nationwide in the past few years.

Dr. Fadl, who works at the Cobble Hill location of Bond Vet, said that the practice had not seen any cases there or at its Williamsburg location recently. Katy Hansen, director of marketing and communications for Animal Care Centers of N.Y.C., said the three shelters run by the organization, which together take in about 6,000 dogs a year, have not recorded an outbreak of leptospirosis either.

How do I protect my dog (and myself)?

Crucially, there is a vaccine. The initial dose is followed by a booster three to four weeks later, and then administered annually. Dr. Fadl generally recommends it, especially given the uptick in the rat population in New York City.

“If you have a private backyard, if your pet is in the parks, if your pet likes to sniff around garbage, drink from standing puddles, get a lepto vaccine,” she said.

“It can save them, it can save you,” she added. “Especially if you have very young people or elderly people that are interacting with this pet, it’s really important to talk to your vet about getting a vaccine.”

Staying away from puddles and pools that could contain rat urine is key. So is keeping your dog away from actual rats, as well as other small rodents, like squirrels, that can spread the disease.

Dr. Fadl also recommended making sure your dog avoids communal water bowls, and instead use a travel bowl or bottle to provide fresh, uncontaminated water to drink.

How are city agencies and dog owners responding?

The McCarren Park Dog Run is a “makeshift area” and not an official dog run, according to the Parks Department, but it is heavily used by local dog owners. The department said it had received only two 311 complaints regarding rodents in the park in the past year.

But the Parks Department switched out the trash receptacles in the area to rat-resistant metal cans on Friday, had an exterminator conduct an inspection, and began on Monday to refresh the area and replace the wood chips that line the ground.

The area was practically deserted on a cold day last week. Dog owners in the area said they were staying away from the park after hearing stories circulating that a dog named Oreo had died from leptospirosis.

Humza Rizvi, 26, of Williamsburg, said fears about the disease’s spread, and the park’s general lack of cleanliness, had kept him from taking his golden retriever Ollie there.

“It’s a dog park, so it’s going to be dirty,” he said. But, he added, “sitting water and things that can apparently spread the disease are always there.”

Billy Lucas, 32, of Williamsburg expressed similar concerns. He said he had returned to the park with Wally, his German shepherd mix, after noticing that a sign warning of an “outbreak” had been taken down. (He noted that the sign he saw did not appear to have been posted by the city.)

“I assumed everything was fine,” he said. “Then a concerned dog owner came up to me and told me that a few puppies have passed away from lepto recently, so we all got out of there.”

Michael Malone, 28, of Williamsburg, said he double checked to make sure his four-month-old Australian Shepherd Rio’s vaccinations were up-to-date and that he had received the leptospirosis shot.

“They encouraged us to get it because of the rats in the area,” he said. “They told us it’s not really common outside of the city, but in the city it’s a good idea to just get it.”