Melioidosis is a disease that wouldn’t come to mind with a sick dog here in Canada. However, it is present in various parts of the world and is also a serious disease in people. Recognizing a case in North America is rare (and it’s easy to miss since most veterinarians haven’t even heard of it, let alone seen a case before). Yet, with the amount of international dog movement, it’s something to be aware of.
A case report in Zoonoses and Public Health (Ryan et al 2018) outlines some of the issues, describing the public health response to a case identified in the US.
Here are the highlights:
- The affected dog was imported from a shelter in Thailand (where the disease is common) to a private shelter in the US.
- Shortly after arrival, the dog was taken to a veterinary clinic for evaluation due to his chronic inability to walk, which had been a problem for about 2 years.
- On arrival, the dog was bright and alert, and pretty much looked like you’d expect for a dog that couldn’t walk and that had lived in a shelter for a couple years. The dog had lost a lot of muscle in his hindlimbs and had abnormal, infected skin from urine scalding (since the dog was also incontinent).
- A urine culture was performed and Burkholderia pseudomallei, the cause of melioidosis, was identified (causing, I assume, much excitement in the lab since this is a bug that is supposed to be handled with higher levels of biosafety than your regular diagnostic lab). See image above of a culture plate with B. pseudomallei (photo credit: Gavin Koh).
- Because of the zoonotic risk, incurable incontinence and lack of a proven way to confidently eliminate the bacterium, the dog was euthanized.
Burkholderia pseudomallei is a bacterium that is normally found in soil and water, particularly in southeast Asian and northern Australia, but it can be found in many other countries. Since it can cause a range of illnesses in people, including life-threatening bloodstream infections and pneumonia, exposure to an infected dog that is shedding the bacterium in urine (+/- other body sites) raises concern. However, it’s important to note that the vast majority of infections in people are thought to come from soil or water exposure, and there is limited evidence of direct animal-human transmission.
The field investigation looked at the shelter, veterinary clinic and lab. Twenty-seven people from the clinic and lab had been exposed to the dog, its urine or the bacterial isolate (excluding anyone who might have had contact with the dog in transit – those individuals are often forgotten and can be very difficult to tract). Sixteen of these people were considered a concern, with 14 classified as low risk, and 2 (both individuals with underlying medical conditions) classified as high risk. One of the high risk individuals was given prophylactic antibiotics. Six of the 16 agreed to symptomatic monitoring by public health personnel, and three agreed to blood tests.
- Six people were identified as potentially exposed in the shelter, but only 3 had direct contact with the dog’s urine. Blood samples were collected from them to see if they had any evidence of exposure to the bacterium.
- No one got sick.
- One person had an increase in antibodies against the bacterium, suggesting exposure, but the increase was minor and therefore inconclusive.
A few take-home messages:
- Logical importation practices are needed. How much time and expense went into shipping a paralysed dog transcontinentally from one shelter to another, when it was ultimately euthanized in the end anyway? I realize everything is done with good intentions, but thank about what could have been done for local homeless animals with the time, effort and expenses that were incurred here.
- Routine basic infection control practices need to be followed in shelters and clinics to protect against situations like this when something unexpected is encountered.
- Moving an individual (human or animal) from one area to another can result in moving pathogens along with them. Understanding the risks from different regions is important, but is also a challenge.
As mentioned in my last post, we’ve started a disease mapping initiative to hopefully help fill some of the knowledge gaps when it comes to regional disease risks in imported dogs. Here’s our first melioidosis map; click here to go to the interactive map that will let you zoom in. Please contact us if you have information relating to other areas where melioidosis is present so we can keep improving the map.