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Importing Disease into North America: An Update

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This is a follow up on an article we published in March about Brucellosis being imported from overseas. Read the articles here and here.

Today Dr. Scott Weese and Dr. Maureen Anderson, of the Ontario Veterinary College’s Centre for Public Health and Zoonoses, published an update entry on their blog, Worms & Germs, titled Brucella canis updates….US Dogs, Canadian Person and Lots of Canadian Dogs. In this update Dr. Weese & Dr. Anderson confirm there are over 100 known or suspected brucellosis positive dogs in Ontario.

Brucellosis concerns were raised several months ago when infected dogs were imported from outside of North America, under the banner of rescue.

Some outlets continue to gloss over the fact that Brucellosis is zoonotic. Brucellosis CAN infect humans (as well as other species).

The BC Medical Journal for May 2019 outlines the first case of an infected human in British Columbia, stating:

“In December 2018 an adult woman presented with a 2-month history of fever, chills, fatigue, weight loss, and headache. Her blood culture tested positive for Brucella canis. She helped transport rescue dogs from Mexico and the US to British Columbia, including a pregnant dog from Mexico that spontaneously aborted two stillborn puppies during transport. The dog tested positive for B. canis by immunofluorescent antibody test.”

… adult woman presented with a 2-month history of fever, chills, fatigue, weight loss, and headache. Her blood culture tested positive for Brucella canis.

https://www.bcmj.org/bccdc/brucellosis-and-other-diseases-imported-dogs

How can humans become infected with B. Canis?

B. Canis typically infects humans via:

  • Through a cut or scratch in the skin
  • When you breathe in contaminated air (rare)
  • When you eat or drink something contaminated with the bacteria, such as unpasteurized milk or undercooked meat

What are the symptoms of canine brucellosis in humans?

Symptoms of B. Canis typically present within 5 to 30 days post exposure and can include:

  • Fever (the most common symptom, with high “spikes” that usually occur in the afternoon)
  • Back pain
  • Body-wide aches and pains
  • Poor appetite and weight loss
  • Headache
  • Night sweats
  • Weakness
  • Abdominal pain
  • Cough

It is reported that symptoms of brucellosis infection can be very vague, and often similar to the flu.

What is canine brucellosis?

Canine brucellosis is a contagious bacterial infection caused by the bacterium, Brucella canis (B. canis). This bacterial infection is highly contagious between dogs. Infected dogs usually develop an infection of the reproductive system, or a sexually transmitted disease.

Brucella canis can infect many other mammals.

Brucella canis is a zoonotic bacterium, which means it not only transmits to dogs but to other mammals, including humans. B. Canis antibodies and/or nucleic acids (DNA/RNA) have been found in:

  • Foxes
  • Coyotes
  • Golden Jackals
  • Raccoon
  • Oncilla (Leopardus tigrinus)
  • Pumas
  • Ocelots
  • Guinea Pigs
  • Mice
  • Cattle
  • Sheep
  • Swine
  • Non-Human Primates
Brucella canis can infect both human and non-human primates.

What are the signs of brucellosis in animals?

Brucellosis in dogs typically causes reproductive problems such as infertility and abortions, with few other signs of clinical illness. The disease is most common in sexually intact adult dogs.

Male dogs infected with brucellosis develop epididymitis, an infection in part of the testicle. A dog with a newly acquired infection will often have an enlarged scrotum or an enlarged testicle and may have a skin rash on the scrotum. The dog may be infertile. In chronic or long-standing cases, the testicles will atrophy or become shrunken.

Female dogs infected with brucellosis develop an infection of the uterus; causing her to be infertile, have difficulty getting pregnant, or she may abort in the late stages of pregnancy. She often has a persistent vaginal discharge. Typically, a pregnant dog with brucellosis will abort at 45-55 days of gestation or will give birth to stillborn or weak puppies that may die a few days after birth.

During the early stages of brucellosis, enlarged lymph nodes are common. Occasionally, B. canis will infect the intervertebral discs, eyes, kidneys, or brain. If the bacterium infects these other tissues, the signs will be related to the bodily system that is infected.

Are there other diseases that humans should be concerned about?

The resounding answer is YES!

On Feb. 27/19, The Kansas Department of Health and Environment sent out a press release alerting the public (see below) about a rabies positive imported dog. The infected dog was part of a shipment of 26 dogs from Egypt at the end of January. All dogs were then adopted. KDHE has instructed new owners to return the dogs for quarantine.

Are there more?

In addition to brucellosis and rabies, there is another zoonotic disease that has been given rise recently, Echinococcus multilocularis (EM) aka a species of tapeworm often referred to as the ‘fox tapeworm’. Ontario had been considered free of the parasite, however, between 2015 and 2017 fecal samples were collected from 460 wild canids in Ontario, 23% were found to be positive for EM. Echinococcus multilocularis is now considered well established in the province.

Small mammals/rodents ingest the eggs, which then hatch in the intestine becoming larvae. During this stage the larvae then migrate to other organs, primarily the liver. Once there, larvae form budding cysts that behave like a malignant tumour, this is called alveolar echinococcosis (AE).

Foxes, coyotes, and other canids (including dogs) become infected by eating infected small animals. Canids can carry the adult worms in their intestinal tracts, and shed the eggs in their feces. This parasite doesn’t progress to AE in canids.

Humans are an accidental host for EM. If a human ingests eggs AE can develop. In humans it’s reported these cysts grow slowly, the incubation period can be 5 to 15 years. AE is considered extremely difficult to treat due to the invasive growth if the parasitic cysts. EM has a mortality rate of 50-75% according the British Columbia Centre for Disease Control.

Table from BC CDC

Brucellosis falls under mandatory reporting. ShowScene has reached out to the Ontario Ministry of Health regarding the number of brucellosis reports received so far this year, a response was not received at time of publication. When/if a response is received, this article will be updated accordingly.

ShowScene has previously reported on Brucellosis in North America here and here.

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