When the Companion Animal Parasite Council (CAPC) released its annual 2020 national parasite forecast in April, it predicted that cases of heartworm would be higher than average this year, especially along the Atlantic coast and Mississippi River. On top of that, the 2020 hurricane season, predicted to be more active than usual, is compounding the threat of bacterial diseases such as canine parvovirus and leptospirosis.

But as the pandemic drags on, fears about the possible transmission of SARS-CoV-2 from humans to pets and vice versa is obscuring the proven zoonotic dangers of clear and present parasitic threats common this time of year, according to CAPC board member Craig Prior, BVSC, CVJ, CAPC.

NEWStat spoke with Prior about the ever-lurking dangers to pets amid the lunacy of 2020.

Hurricanes and evacuations

“We know from past years that when we have a large-scale relocation of shelter animals [during evacuation] for hurricanes, a lot of these dogs may not see a veterinarian [for weeks or months], and then we see a spike in parvo cases,” Prior says. That problem was exacerbated this year due to the mass adoption of shelter animals during the pandemic.

In cases of pets who weren’t treated for heartworm, says Prior, it’ll be six months before they start testing positive, so it’s harder to predict whether we’ll see a hurricane-related spike in cases. However, he adds, “We know that hookworms, roundworms, and whipworms are seasonal, and hookworm infections tend to be highest in the summer months, so we expect a spike in the number of cases [this time of year].”

And those mass pet adoptions will have consequences: “The shelters just emptied,” Prior notes, and many of those shelter animals went months before seeing a veterinarian for basic wellness care due to COVID-related lack of access to care.

But with most hospitals reporting much higher traffic than usual, it’s clear that many of those adoptees are finally getting the basic wellness care they missed out on during the first months of lockdown. And that means more animals are being tested for diseases like heartworm and, hopefully, leptospirosis.

“At CAPC, we compile prevalence data on intestinal parasites—hookworms, roundworms, whipworms, giardia,” Prior says. “So you’re going to see more tick-borne disease: anaplasmosis, ehrlichiosis, and Lyme as well as more heartworm for dogs and cats.”

The CAPC compiles viral data, too: “Lepto is spiking. We have alert maps for that. We’re also putting up alert maps for canine influenza.”

But unlike parasitic-borne disease, Prior says the CAPC can’t really forecast for bacterial disease, in part because they just don’t have the data: “At the hospital level, we regularly test for heartworm and tick-borne diseases,” so the data’s there. “[But] we don’t regularly test for lepto, so it’s a lot harder to predict.”

Prior says factors such as temperature, humidity, and mosquito populations can help the CAPC predict the prevalence of parasitic disease next month in your county. “But diseases like lepto, which potentially depend upon an animal drinking water out of a dirty pond in a dog park, it’s a lot harder to forecast.”

Prior says this is where hurricanes come into play: “You’re going to get displacement of [evacuated] shelter animals again,” Prior says. You’re going to get rain and flooding. “More moisture is going to favor heartworm and mosquitos.”

Changes in preventive protocols

Prior says veterinarians should rethink their preventive care recommendations on historical norms, especially for heartworm. “After hurricanes, all these rescue animals get shipped out of the southeast and [go all over the country],” Prior says. “So we start seeing heartworms show up in places they haven’t been before.” When recommending [preventive care] to clients, Prior says, “You’ve got to take into account the movement of these rescued and displaced animals.”

Emilio DeBess, DVM, MPVM, the State Veterinarian of Oregon and current president of CAPC, echoes Prior’s concern about an active hurricane season and its likely effects on cases of lepto.

“Lepto likes water,” DeBess told NEWStat. “It survives in water very well. [So] any time you have a rain event like a hurricane, or any time an animal goes to a lake, river, or any standing water, there’s the potential for exposure.”

DeBess calls even a single positive lepto test in your county the “tip of the iceberg” in terms of potential cases: “[If] one animal gets diagnosed, there could be many more who could have been exposed and are ill. It can impact human health as well.”

He notes that the disruption to pet wellness care wrought by the pandemic could have far-reaching consequences: “There’s the potential, in the absence of vaccinations and preventive medications, that we’ll see a lot of parvo, distemper, and other conditions that are vaccine-preventable.”

Like Prior, DeBess warns of a pandemic-related lag in test results: “It always takes about two to three months to see these numbers go up,” he adds. “But eventually we will see them go up.”

Check out CAPC’s other tools, such as the 30-Day Parasite Forecast Maps that monitor parasite activity and monthly Top 10 Cities reports that warn of emerging parasitic threats.

Photo credit: © Gettyimages/Michael Repeta