Brucellosis: Info for pig hunting dogs and owners


Brucella suis is present in the feral pig population in the North Burnett and is a notifiable disease. This organism is similar to Brucella abortus, which was eradicated from cattle in Australia during the 1970’s and 80’s. There are other Brucella species, notably B. canis, B .ovis and B. melitensis. They all cause similar problems, but tend to be found in their preferred host (canis in dogs, ovis in sheep, abortus in cattle, and melitensis in sheep and goats). Australia only has B. suis and B. ovis since B. abortus was eradicated. Of all these, B. suis, B. abortus and B. melitensis are the main concern from the human health perspective and can cause severe disease in humans called brucellosis, hence the campaign to eradicate B. aborus from cattle in Australia a few decades ago. In fact, James Herriot describes in his books his personal experience of being infected with Brucella abortus as a veterinarian in England. At present the only Brucella organism posing a risk to human health and known to be present in Australia is B. suis.
B. suis was first isolated from feral pigs in Qld in 1976 and is now widespread in QLD’s feral pig population, and has since spread into feral pigs in NSW. 90% of cases have a history of direct contact with feral pigs during hunting, but there are instances where infection has occurred in family pets that have had no contact with pigs through hunting or eating pig meat, meaning that they must have been infected by other dogs. B. suis is a zoonotic pathogen, meaning that it can infect people. To date, almost all human infections of B. suis have been people involved in pig hunting. Evidence of dog-to-people transmission is scarce, with only a single case report implicating a dog of transmitting brucellosis to a woman who handled aborted pups without gloves.
Brucellosis can be contracted by contact with infected pigs, and by eating uncooked meat from infected pigs. It is a tiny bacteria and becomes airborne easily, and can infect people by being inhaled. Because of the human health risk and difficulty of treating brucellosis in dogs, euthanasia is recommended if a dog is known to have brucellosis. The disease can be transmitted between dogs by sexual activity, and dogs known to have brucellosis should be desexed if the owners are unwilling to allow euthanasia. Even with effective antibiotic treatment the damage done by the infection cannot always be reversed.
People should avoid contact with feral pigs, including their blood, urine and saliva, and especially avoid cutting up carcasses of feral pigs as this presents a high risk of transmission. Meat from feral pigs should not be fed to dogs.

In dogs brucellosis tends to present as two main syndromes. In entire (not desexed) dogs the organism tends to localise in the reproductive organs, causing abortions in females and inflammation of the testicles and epididymis in males. In desexed dogs the tendency is to infect bones of the spine and hips, causing pain and even fractures if the bone is weakened enough by the infection. These are only general distinctions, and not always true. A recent case in an entire, 5 year old male dog from Gayndah presented in late January 2018 with kidney failure and back pain associated with bone infection, but no evidence of infection in testicles and scrotum. This was the first diagnosis of brucellosis in the Gayndah area.
If a dog has been involved in pig hunting and presents with any of the following symptoms:
• Inflammation/swelling of the testicles and scrotum
• Back pain
• Abortion
• Fever
brucellosis should be considered and tested for.
Symptoms of brucellosis in people can include:
• fluctuating fever (coming and going at different times of day)
• headache
• muscular pain (especially in the shoulder and neck regions)
• night sweating
• general weakness and depression
• Enlargement of the liver and spleen sometimes occurs
The initial, severe symptoms of the disease in humans usually subside within about 3 weeks, but some untreated people will be chronically ill for years. Relapses are common, even after treatment with antibiotics, probably because the bacteria lives inside cells where it is protected from the antibiotic by the host cell. In humans infection of the bone can occur, particularly in the spine and hips, and some cases develop meningitis (inflammation of the brain), myelitis (inflammation of the spinal cord) and some will develop neuro-psychological disorders (in other words, go nutty, as James Herriot experienced himself).
Any person that has:
• been involved in pig hunting
• had any other contact with feral pigs, including handling uncooked pig meat
• been in contact with dogs that have hunted pigs or eaten pig meat
should be aware of the symptoms of brucellosis, and seek medical advice regarding testing and treatment of any symptoms, including flu-like symptoms. It is important to alert medical doctors to the possibility of brucellosis in these cases.

For more information please refer to the following links

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