Buruli Ulcer – Experts warn against mosquitoes and handling possums

Buruli Ulcer – Experts warn against mosquitoes and handling possums

As cases of Buruli ulcer continue to increase across Victoria, infectious disease experts are encouraging steps to avoid mosquite bites, and urging caution in handling sick or injured wildlife, with a small number of cases of Buruli Ulcer appearing in people after being bitten or scratched by an infected possum.

Buruli ulcer (sometimes referred to as the Bairnsdale ulcer) is a skin infection caused by the bacterium Mycobacterium ulcerans.

The toxins made by the bacteria destroy skin cells, small blood vessels and the fat under the skin, which causes ulceration and skin loss. Lesions typically present as a slowly enlarging painless lump or wound which can initially be mistaken for an insect bite.

There is increasing evidence that mosquito bites and possums play a role in disease transmission in Victoria.

Research has shown that areas where humans are most frequently contracting Buruli ulcer are areas where soil, mosquitoes and possums are most frequently carrying the causative bacteria. Infections are also more likely acquired in the warmer months but can be acquired at any time of the year.

Local Buruli Ulcer expert and Deputy Director of Barwon South West Public Health Unit, Assoc Professor Daniel O’Brien, says he has encountered a couple of cases where patients have been infected after they have been bitten or scratched by an unwell possum whilst trying to help it.

“I’ve treated a couple of cases locally where upon investigating possible sources of their ulcer, we have discovered they have handled a sick possum and then been bitten or scratched by it.”

“I encourage anyone that comes across a sick possum, especially one displaying an open sore or ulcer, to  refrain from handling the animal and seek assistance from wildlife assistance services or Veterinarians who have experience in handling sick wildlife. If handling the possum is unavoidable, take precautions such as wearing protective clothing,” he says.

Victoria is home to several species of possum including the common brushtail and common ringtail possum. Possums are protected species of native marsupials that are an important part of Victoria’s forest and woodland ecosystems as well as being adapted to urban environments.

As the region approaches the peak infection period, it is important for those that come across possums, especially if sick or with exposed ulcers, to take care and protect themselves against possible infection.

The highest risk for infection occurs during the warmer months, but it usually takes between 4-5 months for an ulcer to develop following infection.

The following precautions can reduce your risk:

• Avoid handling possums and instead seek assistance from wildlife assistance services
• If handling is unavoidable, take precautions such as wearing thick gloves that ideally extend up your arm and full length sleeved clothing
• If scratched by a possum, clean the wound thoroughly, wash with antiseptic and monitor the wound.
• When gardening, working or spending time outdoors:
  • Wear gardening gloves, long sleeved shirts and trousers
  • Wear insect repellent on any exposed skin
  • Protect cuts and abrasions with a dressing
  • Promptly wash any new scratches or cuts you receive with soap and apply a topical antiseptic and dressing.
• Reduce mosquito breeding sites around houses and other accommodation by reducing areas where water can pool (including pot plant containers, buckets, open tins or cans, discarded tyres, and other untreated, freshwater pools).
• Mosquito proof your home by securing insect screens on accommodation.
• Avoid mosquito bites by:
  • Using personal insect repellents containing diethyltoluamide (DEET) or picaridin
  • Covering up by wearing long, loose-fitting, light-coloured clothing
  • Avoiding mosquito-prone areas and vector biting times, especially at dusk and dawn.
• Exposed skin contaminated by soil or water should be washed following outdoor activities. 
• See your doctor early if you have a slow-healing or suspicious skin lesion.

For more information on Buruli Ulcer go to Buruli ulcer – Better Health Channel

For information on what to do about sick or injured wildlife go to www.wildlife.vic.gov.au