Tag Archives: lake erie

Tularemia in muskrats: Long Point, Ontario (that’s in Canada)

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For a Brantford kid, Port Dover on the glimmering shores of Lake Erie was the closest beach; but for the full Lake Erie experience, we would drive a little further west to Long Point.

My friend Scott Weese, who is apparently treating the lock-down like I do, by writing more because ya don’t have to waste time at stupid meetings or commuting, writes in his Worms and Germs Blog that a recent report from the Canadian Wildlife Health Cooperative (CWHC) describes an outbreak of tularemia in muskrats in Long Point, Ontario. Tularemia is a potentially nasty disease caused by the bacterium Francisella tularensis. While not many people have contact with muskrats or live in Long Point, it’s still noteworthy.

 The investigation was initiated following a report of at least 35 sick or dead muskrats in the area. Necropsies were done on some of the rodents, and they were found to have enlarged lymph nodes and lesions in their spleens and livers. Testing at the National Microbiology Laboratory identified Francisella tularensis.  This was done at the national lab because F. tularensis is a containment level 3 pathogen requiring enhanced biosafety practices – so it’s not a bacterium which regular labs handle.

This isn’t a new finding, since we know this bacterium is present in Ontario, but it’s rare. Francisella tularensis is sporadically found in various animals and rarely in people (there’s been one reported human case in Ontario so far in 2020). It’s a reportable disease in animals and people because of the potential severity of infection, and because it’s a potential bioterrorism agent.

Back to the muskrats… tularemia is a rare finding in wildlife. That doesn’t mean it doesn’t cause disease, since sporadic disease in wildlife rarely gets investigated. It’s most commonly associated with rabbits, and human and domestic animal infections can be associated with rabbit or rodent contact. The fact that this occurred as an outbreak with a significant number of animals affected over a short period of time is interesting, and it’s also concerning from human and animal health standpoints. The bacterium can be spread in a variety of ways, including direct contact, inhalation (e.g. running over an infected animal with a lawnmower and aerosolizing the bug and then breathing it in… gross but true) and via some insects (e.g. ticks, deer flies).

Tularemia avoidance measures are pretty basic:

Avoid contact with wildlife, live or dead.

People handling dead wildlife, especially those handling them closely such as trappers, should use good routine hygiene and infection control practices.

Avoid ticks. For pets, that involves use of a good tick preventive. For the rest of us, well… we don’t have a chewable tick preventive but we can do other things to reduce the risk of tick exposure, including (and most importantly) doing “tick checks” if you’ve been outside in an area where ticks are likely to be lurking.

Keep your pets under control, especially if they are prone to chasing wildlife or snacking on dead animals (also gross but true).

The CWHC warning is pretty similar to my comments: “During an outbreak situation, it is presumed that bacterial levels would be higher in the surrounding environment, so caution is warranted for anyone who is traversing through the area or wading into the water in the Crown Marsh area of Long Point. There is also a danger to off-leash dogs as they can become infected and develop similar symptoms to humans, especially if they consume infected meat. It is recommended that dogs are kept on leash and monitored closely while in this area. It is recommended that people do not handle wildlife found dead unless they are wearing protective gloves (or a similar protective barrier) to prevent direct contact of the animal with the skin. Anyone who handles dead wildlife (even while wearing the appropriate protective gear) should wash their hands thoroughly to minimize the chances of exposure.”

A related topic that applies to animals and people is talking to healthcare providers about travel. The risk for various diseases differs geographically. A disease might not be on a physician’s or veterinarian’s list of considerations if they don’t know about travel. So, physicians and veterinarians need to query travel history, and everyone needs to remember that travel means going somewhere else, regardless where it is (even if they haven’t left the province).

Here’s a scenario that highlights that:

Me: Have you traveled with your dog lately?

Owner: No.

Me: Do you have a cottage?

Owner: Yes, it’s a beautiful place a couple of hours from here. We go there every weekend in the summer.

Me: So, you travel with your dog every weekend in the summer?

Owner: Well, that’s not travel, it’s going to the cottage.

Me: Ok, now let’s talk about the different things I need to consider now that I know your dog travels.

That’s not an unusual situation. Understanding where people and animals have been is important when thinking about infectious disease risks. Veterinarians and owners need to clearly communicate to identify potential problems.

Chlorine works: 12 dead, 87 sick from Legionnaires’ linked to Michigan water supply 2014-15

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An outbreak of Legionnaires’ disease that killed 12 people and sickened at least 87 in Flint, Mich., in 2014 and 2015 was caused by low chlorine levels in the municipal water system, scientists have confirmed. It’s the most detailed evidence yet linking the bacterial disease to the city’s broader water crisis.

Rebecca Hersher of NPR reports that in April 2014, Flint’s water source switched from Lake Huron to the Flint River. Almost immediately, residents noticed tap water was discolored and acrid-smelling. By 2015, scientists uncovered that the water was contaminated with lead and other heavy metals.

Just months after the water source changed, hospitals were reporting large numbers of people with Legionnaires’ disease.

“It’s a pneumonia, but what’s different about it is, we don’t share it like we do the flu or common cold,” explains Michele Swanson of the University of Michigan, who has been studying Legionnaires’ for 25 years. “It’s caused by a bacterium,Legionella pneumophila, that grows in water.”

The bug can enter the lungs through tiny droplets, like ones dispersed by an outdoor fountain or sprinkler system, or accidentally inhaled if a person chokes while drinking.

“If you don’t have a robust immune system, the microbe can cause a lethal pneumonia,” she says. In a normal year, the disease is relatively rare — about six to 12 cases per year in the Flint area, according to Swanson. During the water crisis, that jumped up to about 45 cases per year.

Although the outbreak of Legionnaires’ happened at the same time as the Flint water crisis, it was initially unclear how the two were connected. After earlier research suggested that chlorine levels might be the key, Swanson and colleagues at the University of Michigan in Ann Arbor, Sammy Zahran of Colorado State University and a team of researchers at Wayne State University in Detroit, began analyzing detailed water and epidemiological data from the six-year period before, during and after the crisis.

“We know that Legionella is sensitive to chlorine in the laboratory,” says Swanson. The chlorine makes it difficult for the bacteria to replicate, which is one reason water companies often add chlorine to their systems. But when Flint’s water source changed, the chlorine level dropped and cases of Legionnaires’ disease spiked. “It was the change in water source that caused this Legionnaires’ outbreak,” Swanson says.

The new research was published in a pair of studies in the Proceedings of the National Academy of Sciences and the journal mBio on Monday. The conclusion may bolster parts of the case being brought against Nick Lyon, the former Michigan Department of Health and Human Services director, who is being tried for involuntary manslaughter in connection with the Legionnaires’ deaths.

From April 2014 to October 2015, the Flint River served as Flint’s water source. During the same period, cases of Legionnaires’ disease increased from less than a dozen per year to about 45 per year, and 12 people died of the waterborne disease.

The new studies also suggest that a complex set of factors may be responsible for low chlorine levels during the crisis. In addition to killing microbes, chlorine can react with heavy metals like lead and iron, and with organic matter from a river. That means lead and iron in the water may have decreased the amount of chlorine available to kill bacteria.