Each year, more and more Victorians become sick with a flesh-eating bacteria known as Buruli ulcer. Last year, 363 people presented with the infection, the highest number since 2004.

But it has been unclear exactly how it spreads, until now. New research shows mosquitoes are infected from biting possums that carry the bacteria. Mozzies spread it to humans through their bite.

What is Buruli ulcer?

Buruli ulcer, also known as Bairnsdale ulcer, is a skin infection caused by the bacterium Mycobacterium ulcerans.

It starts off like a small mosquito bite and over many months, slowly develops into an ulcer, with extensive destruction of the underlying tissue.

While often painless initially, the infection can become very serious. If left untreated, the ulcer can continue to enlarge. This is where it gets its “flesh-eating” name.

Thankfully, it’s treatable. A six to eight week course of specific antibiotics is an effective treatment, sometimes supported with surgery to remove the infected tissue.

Where can you catch it?

The World Health Organization considers Buruli ulcer a neglected tropical skin disease. Cases have been reported across 33 countries, primarily in west and central Africa.

However, since the early 2000s, Buruli ulcer has also been increasingly recorded in coastal Victoria, including suburbs around Melbourne and Geelong.

Scientists have long known Australian native possums were partly responsible for its spread, and suspected mosquitoes also played a role in the increase in cases. New research confirms this.

Our efforts to ‘beat Buruli’

Confirming the role of insects in outbreaks of an infectious disease is achieved by building up corroborating, independent evidence.

In this new research, published in Nature Microbiology, the team (including co-authors Tim Stinear, Stacey Lynch and Peter Mee) conducted extensive surveys across a 350 km² area of Victoria.

We collected mosquitoes and analysed the specimens to determine whether they were carrying the pathogen, and links to infected possums and people. It was like contact tracing for mosquitoes.

Molecular testing of the mosquito specimens showed that of the two most abundant mosquito species, only Aedes notoscriptus (a widespread species commonly known as the Australian backyard mosquito) was positive for Mycobacterium ulcerans.

We then used genomic tests to show the bacteria found on these mosquitoes matched the bacteria in possum poo and humans with Buruli ulcer.

We further analysed mosquito specimens that contained blood to show Aedes notoscriptus was feeding on both possums and humans.

To then link everything together, geospatial analysis revealed the areas where human Buruli ulcer cases occur overlap with areas where both mosquitoes and possums that harbour Mycobacterium ulcerans are active.

Stop its spread by stopping mozzies breeding

The mosquito in this study primarily responsible for the bacteria’s spread is Aedes notoscriptus, a mosquito that lays its eggs around water in containers in backyard habitats.

Controlling “backyard” mosquitoes is a critical part of reducing the risk of many global mosquito-borne disease, especially dengue and now Buruli ulcer.

You can reduce places where water collects after rainfall, such as potted plant saucers, blocked gutters and drains, unscreened rainwater tanks, and a wide range of plastic buckets and other containers. These should all be either emptied at least weekly or, better yet, thrown away or placed under cover.

There is a role for insecticides too. While residual insecticides applied to surfaces around the house and garden will reduce mosquito populations, they can also impact other, beneficial, insects. Judicious use of such sprays is recommended. But there are ecological safe insecticides that can be applied to water-filled containers (such as ornamental ponds, fountains, stormwater pits and so on).

Recent research also indicates new mosquito-control approaches that use mosquitoes themselves to spread insecticides may soon be available.

How to protect yourself from bites

The first line of defence will remain personal protection measures against mosquito bites.

Covering up with loose fitted long sleeved shirts, long pants, and covered shoes will provide physical protection from mosquitoes.

Applying topical insect repellent to all exposed areas of skin has been proven to provide safe and effective protection from mosquito bites. Repellents should include diethytolumide (DEET), picaridin or oil of lemon eucalyptus.

While the rise in Buruli ulcer is a significant health concern, so too are many other mosquito-borne diseases. The steps to avoid mosquito bites and exposure to Mycobacteriam ulcerans will also protect against viruses such as Ross River, Barmah Forest, Japanese encephalitis, and Murray Valley encephalitis.

Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of Sydney; Peter Mee, Adjunct Associate Lecturer, School of Applied Systems Biology, La Trobe University; Stacey Lynch, Team Leader- Mammalian infection disease research, CSIRO, and Tim Stinear, Professor of Microbiology, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The vagina is an internal organ with a complex ecosystem, influenced by circulating hormone levels which change during the menstrual cycle, pregnancy, breastfeeding and menopause.

Around and after menopause, there are normal changes in the growth and function of vaginal cells, as well as the vagina’s microbiome (groups of bacteria living in the vagina). Many women won’t notice these changes. They don’t usually cause symptoms or concern, but if they do, symptoms can usually be managed.

Here’s what happens to your vagina as you age, whether you notice or not.

Let’s clear up the terminology

We’re focusing on the vagina, the muscular tube that goes from the external genitalia (the vulva), past the cervix, to the womb (uterus). Sometimes the word “vagina” is used to include the external genitalia. However, these are different organs and play different roles in women’s health.

What happens to the vagina as you age?

Like many other organs in the body, the vagina is sensitive to female sex steroid hormones (hormones) that change around puberty, pregnancy and menopause.

Menopause is associated with a drop in circulating oestrogen concentrations and the hormone progesterone is no longer produced. The changes in hormones affect the vagina and its ecosystem. Effects may include:

• less vaginal secretions, potentially leading to dryness
• less growth of vagina surface cells resulting in a thinned lining
• alteration to the support structure (connective tissue) around the vagina leading to less elasticity and more narrowing
• fewer blood vessels around the vagina, which may explain less blood flow after menopause
• a shift in the type and balance of bacteria, which can change vaginal acidity, from more acidic to more alkaline.

What symptoms can I expect?

Many women do not notice any bothersome vaginal changes as they age. There’s also little evidence many of these changes cause vaginal symptoms. For example, there is no direct evidence these changes cause vaginal infection or bleeding in menopausal women.

Some women notice vaginal dryness after menopause, which may be linked to less vaginal secretions. This may lead to pain and discomfort during sex. But it’s not clear how much of this dryness is due to menopause, as younger women also commonly report it. In one study, 47% of sexually active postmenopausal women reported vaginal dryness, as did around 20% of premenopausal women.

Other organs close to the vagina, such as the bladder and urethra, are also affected by the change in hormone levels after menopause. Some women experience recurrent urinary tract infections, which may cause pain (including pain to the side of the body) and irritation. So their symptoms are in fact not coming from the vagina itself but relate to changes in the urinary tract.

Not everyone has the same experience

Women vary in whether they notice vaginal changes and whether they are bothered by these to the same extent. For example, women with vaginal dryness who are not sexually active may not notice the change in vaginal secretions after menopause. However, some women notice severe dryness that affects their daily function and activities.

In fact, researchers globally are taking more notice of women’s experiences of menopause to inform future research. This includes prioritising symptoms that matter to women the most, such as vaginal dryness, discomfort, irritation and pain during sex.

If symptoms bother you

Symptoms such as dryness, irritation, or pain during sex can usually be effectively managed. Lubricants may reduce pain during sex. Vaginal moisturisers may reduce dryness. Both are available over-the-counter at your local pharmacy.

While there are many small clinical trials of individual products, these studies lack the power to demonstrate if they are really effective in improving vaginal symptoms.

In contrast, there is robust evidence that vaginal oestrogen is effective in treating vaginal dryness and reducing pain during sex. It also reduces your chance of recurrent urinary tract infections. You can talk to your doctor about a prescription.

Vaginal oestrogen is usually inserted using an applicator, two to three times a week. Very little is absorbed into the blood stream, it is generally safe but longer-term trials are required to confirm safety in long-term use beyond a year.

Women with a history of breast cancer should see their oncologist to discuss using oestrogen as it may not be suitable for them.

Are there other treatments?

New treatments for vaginal dryness are under investigation. One avenue relates to our growing understanding of how the vaginal microbiome adapts and modifies around changes in circulating and local concentrations of hormones.

For example, a small number of reports show that combining vaginal probiotics with low-dose vaginal oestrogen can improve vaginal symptoms. But more evidence is needed before this is recommended.

Where to from here?

The normal ageing process, as well as menopause, both affect the vagina as we age.

Most women do not have troublesome vaginal symptoms during and after menopause, but for some, these may cause discomfort or distress.

While hormonal treatments such as vaginal oestrogen are available, there is a pressing need for more non-hormonal treatments.

Dr Sianan Healy, from Women’s Health Victoria, contributed to this article.

Louie Ye, Clinical Fellow, Department of Obstetrics and Gynecology, The University of Melbourne and Martha Hickey, Professor of Obstetrics and Gynaecology, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.