Out of 300 dogs tested, several are found to have high or significant levels of toxin.
(Getty Images)As the fallout from the Flint water crisis continues, veterinarians at Michigan State University are looking deeper into how extensively toxic lead levels in the water supply affected the city's pets.
Daniel Langlois, assistant professor with Michigan State University's College of Veterinary Medicine, offered six lead testing clinics for dogs in Flint over the last few months, aided by monetary gifts and volunteer veterinary professionals.
More confirmed cases
Of the 300 total dogs tested for lead, four were found to have high or significant levels. Two of the dogs were subclinical, one had very mild neurological signs, and the fourth had some neurological signs and possible seizures. Overall, Langlois characterizes the cases as mild and said the source of exposure has been eliminated. The most symptomatic dogs received dimercaptosuccinic acid, also called succimer, a chelating agent.
Another 15 to 20 dogs tested positive for lead, but the levels were below the reportable limit of 50 parts per billion. The low levels and lack of clinical signs suggest the dogs had previous or low-level chronic exposure.
No additional testing clinics are currently planned, though Langlois says that despite interventions, there are still some households testing at lead levels above federal guidelines.
Pet-specific toxicity factors
Dogs aren't any more or less susceptible to lead poisoning than people, but they are more likely to experience lead exposure continuously, Langlois says. While people may drink water from different sources or even consume other beverages, dogs are confined to the water in their homes. Another factor that contributes to toxicity in dogs-or any pet-is that they can't verbalize early symptoms like changes in cognition or headaches. “By the time you notice it, it's more severe,” Langlois says.
Though there have been isolated reports of acute cases primarily with gastrointestinal or neurologic symptoms, Langlois says blood toxicity today is a very rare condition.
“At a minimum, this has certainly raised the awareness for lead poisoning across the state, and especially in Flint,” he says.
Langlois says that while other pets experience just as much risk as dogs, the clinics targeted dogs because they're easier to screen. None of the 20 to 30 cats that were screened along the way tested positive for lead toxicity.
The crisis in Flint
The crisis began in April 2014 when the city of Flint began using treated water from the Flint River instead of Lake Huron. The river water's corrosive properties increased the amount of lead being released from the city's aging pipes, and thousands of people tested positive for toxic levels of lead in their blood. Because lead can cause serious cognitive damage in children and kidney issues in adults, President Obama responded to the crisis by declaring a state of emergency in January 2016.
Residents around Flint have been given bottled water and special filtration systems-particularly those in homes with older pipes that are more likely to leach lead into the water supply. The cost to undo the damage and repair the infrastructure could be in the billions, officials have said.
Not to be forgotten, however, are the pets of Flint homeowners, who may or may not have access to bottled or filtered water.
Jennifer Holton, a spokesperson for the office of James Averill, DVM, Michigan's state veterinarian, says there have been a total of seven confirmed cases of lead toxicosis-a reportable condition-in Michigan since October 2015. She says pet owners with any concerns should work directly with a licensed veterinarian instead of contacting the state veterinarian's office. Holton adds, “Whatever people are doing for themselves, they should be doing for their pets.”
Langlois says the lessons learned in Flint extend across the profession. “In terms of clinical signs, [lead toxicity] is vague and nonspecific,” he says. “The index of suspicion had really disappeared because of the rarity of cases, but it's still out there.”
Particularly in areas like Flint that carry high risk factors, such as older homes and poor infrastructure, veterinarians should be mindful to consider lead toxicity in cases with gastrointestinal and neurological symptoms that have no other explanation, Langlois says.
The American Society for the Prevention of Cruelty to Animals Animal Poison Control Center offers detailed guidance to identifying and treating lead poisoning in animals.
Rachael Zimlich is a freelance writer in Cleveland, Ohio, and former staff reporter for dvm360.