A severe tissue-destroying ulcer once rare in Australia is rapidly spreading and is now at epidemic proportions in regions of Victoria, prompting infectious diseases experts to call for urgent research into how it is contracted and spread. 
 
 In an article published in the Medical Journal of Australia (MJA) on Monday, authors led by associate professor Daniel O’Brien from Barwon Health said incidents of Buruli ulcer were on the rise but researchers were baffled as to why Victoria was being particularly affected. There have been no reported cases in New South Wales, South Australia or Tasmania. 
 
 In 2016, there were 182 new cases of the ulcer in Victoria – the highest ever reported by 72%, O’Brien said. But he added that cases reported until 11 November 2017 had further increased by 51% compared with the same period in 2016, from 156 cases to 236 cases. 
 
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 “Despite being recognised in Victoria since 1948, efforts to control the disease have been severely hampered because the environmental reservoir and mode of transmission to humans remain unknown,” O’Brien said. “It is difficult to prevent a disease when it is not known how infection is acquired.” 
 
 The first sign of infection is usually a painless lump on the skin often dismissed as an insect bite. The slow-moving infection then burrows into a layer of fat located between the skin and the lining that covers muscles. It is in this fatty layer that the infection takes hold, spreading sideways and through the body, destroying tissue along the way, before eventually erupting back through the skin in the form of an ulcer. Those with the infection often have no idea the infection has taken hold until the ulcer appears. But when the ulcer does erupt, the pain can be extreme. 
 
 Anyone is susceptible. While the infection responds to a roughly eight-week course of antibiotics, in rare cases surgery to remove skin or even amputation is needed. 
 
 Prof Paul Johnson is an internationally renowned Buruli ulcer expert and has been studying the infection since 1993. He led the development of a highly accurate diagnostic test for the bacteria that causes the disease and is now based at Austin Health in Victoria, where he is trying to understand why the infection is most common on the Bellarine and Mornington peninsulas. 
 
 This has confused researchers because the disease is most often associated with swampland areas in tropical countries and it is found at the greatest frequency in Africa. Cases are also becoming more severe. 
 
 “It seems to occur in very specific areas of Victoria,” Johnson said. “If you don’t enter an endemic area, you don’t get the disease. But what is it about the area that contains it, and what happens to you that means you pick the disease up from that area? Those are the big questions we’ve been asking.” 
 
 He also said the infection had a “very odd” distribution. “When you enter an endemic area, it looks the same as the area you just left,” he said. 
 
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 Johnson believes it is most likely the bacteria that causes the ulcer, Mycobacterium ulcerans, is being spread by mosquitoes and possums. His research team caught a large number of mosquitoes in affected areas and found a small proportion did carry the bacteria. 
 
 They then found ringtail possums in affected areas excreted the bacteria in their faeces. 
 
 “Our hypothesis is really that this is a disease of possums,” he said. “It sweeps through possums and contaminates the local environment through their poo including contaminating mosquitoes, and people are picking it up predominately from biting insects, and maybe directly from possums.” 
 
 There could be other modes of transmission though, he said, and he said researchers did not know how possums contracted and spread the disease. Johnson said that unlike malaria, which is rapidly spread by mosquitoes, transmission of Mycobacterium ulcerans appeared to be more inefficient. 
 
 The authors of the MJA article called for urgent government funding to research the bacteria and to carry out an exhaustive examination of the environments it is found, including looking at local animals and any interaction with people. 
 
 “The time to act is now,” the authors wrote. 
 
 Johnson agreed but added there were some precautions people in affected areas could take such as avoiding mosquito bites, cleaning and covering any cuts sustained outdoors, and going to the doctor if they had any concerns. ||||| In the last year, cases of a ghastly but mysterious flesh-eating bacterial infection have more than doubled in Victoria, Australia, raising alarm among health experts. 
 
 There were 239 cases of the flesh-eating infections in the past 12 months, according to figures (PDF) released this week by health authorities. In 2016, there were only 102 reported cases, while 2015 and 2014 tallied just 58 and 47. And the rate of new infections is currently skyrocketing: in the past few months, case counts hit nine per week, according to Australia’s Nine News. The number of severe cases has also doubled. 
 
 While the rises alone are enough to worry health experts, the fact that virtually nothing is known about the cause of the infection has some dismayed. 
 
 “I’m at the forefront as a clinician trying to treat patients and getting more and more overwhelmed but also distressed at the fact that we are doing nothing to try and prevent people getting it in the first place,” Dr. Daniel O’Brien, of Royal Melbourne and Geelong hospitals, told Nine News. 
 
 Baffling bacteria 
 
 The infections are caused by Mycobacterium ulcerans, a slow-growing bacterium that causes gaping, palm-sized ulcers. Sometimes called Buruli ulcers, the lesions seem to dissolve skin and gnaw away at tissue. The bacteria are known to lurk around Victoria, but experts don’t know where it lives or how it spreads. 
 
 “There are theories about transmission via mosquitos, theories about it being in the soil and getting through wounds, theories about whether some animals are involved, in that we know that some possums can be affected by it,” O’Brien said. “But we don’t actually know where it lives, why it’s there, and how it gets spread to humans. How can we possibility halt an epidemic when we don’t have that basic information?” 
 
 The bacterium was first identified in Australia in 1948, but the ulcers get their name from Buruli county (now called Nakasongola) in Uganda, where researchers reported large numbers of ulcers in the 1960s. 
 
 It’s now known to skulk in at least 33 countries, and the World Health Organization considers it “largely a problem of the poor in remote rural areas (PDF).” It causes a few thousand cases worldwide each year, most of which are in children under the age of 15. 
 
 Antibiotics are usually effective at treating the lesions. But, early treatment is critical to reducing skin loss and tissue damage. Victims often need surgery to clean out dead flesh and repair wounds. 
 
 Zombie limbs 
 
 There are currently no prevention strategies or vaccines. Despite decades of knowing about the bacteria, researchers are still stumped by them. A study published just this April added weight to the idea that the bacteria are somehow linked to disturbed water sources, such as those with flooding or deforestation. 
 
 A study out last month looked at where the ulcers show up on people. The study of 579 patients found that they tend to cluster on arms and legs. The researchers, co-led by O’Brien, concluded: 
 
 “We propose that targeting behavior by biting insects rather than direct contact with a contaminated environment best explains the lesion distribution we observed.” 
 
 One likely source of confusion for researchers is the slow-growing nature of M. ulcerans. It’s unclear how quickly symptoms show up after a person is infected, but authorities estimate that it’s somewhere in the range of four weeks to nine months. Such a large window can make it difficult to pinpoint when or where an exposure occurred, let alone how. 
 
 “For me this is an urgent health problem that our community needs addressed,” O’Brien said. “I think our government should be putting significant amounts of money into trying to stop it and that means research.” 
 
 This week, a 13-year-old girl from Tyabb, Victoria, started an online petition to urge Health Minister Greg Hunt to provide more research funding for the disease. The girl was stricken with a Buruli ulcer on her knee in April and is still recovering. She needed three surgeries to clear out rotting flesh. (Here's a picture of her ulcer, but warning, it's gruesome.) 
 
 “It’s still not looking that great,” she said. “We call it the zombie leg.”
– "It is difficult to prevent a disease when it is not known how infection is acquired," reads a study published Monday that tracks the spread of a flesh-eating ulcer in Australia, and that's not the only mystery surrounding the rise in Buruli ulcers. The disease has historically most often struck in tropical and swampy parts of Africa, but incidents of it have surged in Victoria, which the BBC notes has a "temperate" climate—and only Victoria, with no cases reported in the neighboring Australian states of New South Wales, South Australia, and Tasmania. The ulcers were first reported in Victoria 70 years ago, but the surge is a recent one: 182 new cases in 2016, a 72% rise over the previous high; and though total 2017 figures weren't in, the year was shaping up to show 50% more cases than in 2016. Buruli expert Paul Johnson, who was not involved in the study, notes the oddities about how the disease appears in Victoria, telling the Guardian, "If you don’t enter an endemic area, you don’t get the disease." But "when you enter an endemic area, it looks the same as the area you just left." He suspects the bacteria that causes the ulcer is carried by mosquitoes and possums. The bacteria produces toxins that eat through fat, skin cells, and blood vessels in the fatty layer of the skin; it's only once the ulcer erupts through the skin's outer layer that a person becomes aware they are infected. The study, which appears in the Medical Journal of Australia, argues government funding needs to quickly be dedicated to studying the ulcer in order to answer six critical questions, including "why are cases becoming more severe?" (The bacteria gave this girl a "zombie leg.")