You might have heard of something called “cryptosporidiosis” recently, closely followed by warnings to stay away from your local swimming pool if you’ve had diarrhoea.

More than 700 cases of this gastrointestinal disease were reported in Queensland in January, which is 13 times more than in January last year. Just under 500 cases have been recorded in New South Wales this year to-date, while other states have similarly reported an increase in the number of cryptosporidiosis infections in recent months.

Cryptosporidiosis has been listed as a national notifiable disease in Australia since 2001.
But what exactly is it, and should we be worried?

What causes cryptosporidiosis, and who is affected?

Cryptosporidiosis is the disease caused by the parasite Cryptosporidium, of which there are two types that can make us sick. Cryptosporidum hominis only affects humans and is the major cause of recent outbreaks in Australia, while Cryptosporidium parvum can also affect animals.

The infection is spread by spores called oocysts in the stools of humans and animals. When ingested, these oocysts migrate and mature in the small bowel. They damage the small bowel lining and can lead to diarrhoea, nausea, vomiting, fever and abdominal discomfort.

Most people develop symptoms anywhere from one to 12 days after becoming infected. Usually these symptoms resolve within two weeks, but the illness may last longer and can be severe in those with a weakened immune system.

Children and the elderly tend to be the most commonly affected. Cryptosporidiosis is more prevalent in young children, particularly those under five, but the disease can affect people of any age.

So how do we catch it?

Most major outbreaks of cryptosporidiosis have been due to people drinking contaminated water. The largest recorded outbreak occurred in Milwaukee in 1993 where 403,000 people were believed to have been infected.

Cryptosporidium oocysts are very small in size and in Milwaukee they passed through the filtration system of one of the water treatment plants undetected, infecting the city’s water supply. As few as ten oocysts can cause infection, making it possible for contaminated drinking water to affect a very large number of people.

Four days after infection a person with cryptosporidiosis can shed up to ten billion oocysts into their stool a day, with the shedding persisting for about two weeks. This is why one infected person in a swimming pool can infect the entire pool in a single visit.

Cryptosporidium oocysts excreted in the faeces of infected humans and animals can also reach natural bodies of water such as beaches, rivers and lakes directly through sewer pipes or indirectly such as in manure transported with surface runoff after heavy rain.

One study which modelled Cryptosporidium concentrations in rivers around the world estimated there are anywhere from 100 to one million oocysts in a litre of river water.

In Australia, cryptosporidiosis outbreaks tend to occur during the late spring and early summer periods when there’s an increase in recreational water activities such as swimming in natural water holes, water catchments and public pools. We don’t know exactly why cases have seen such a surge this summer compared to other years, but we know Cryptosporidium is very infectious.

Oocysts have been found in foods such as fresh vegetables and seafood but these are not common sources of infection in Australia.

What about chlorine?

Contrary to popular belief, chlorine doesn’t kill off all infectious microbes in a swimming pool. Cryptosporidium oocysts are hardy, thick-walled and resistant to chlorine and acid. They are not destroyed by chlorine at the normal concentrations found in swimming pools.

We also know oocysts can be significantly protected from the effects of chlorine in swimming pools by faecal material, so the presence of even small amounts of faecal matter contaminated with Cryptosporidium in a swimming pool would necessitate closure and a thorough decontamination.

Young children and in particular children in nappies are known to increase the potential for disease transmission in recreational water. Proper nappy changing, frequent bathroom breaks and showering before swimming to remove faecal residue are helpful ways to reduce the risk.

Some sensible precautions

Other measures you can take to reduce yours and others’ risk of cryptosporidiosis include:

• avoid swimming in natural waters such as rivers and creeks during and for at least three days after heavy rain
• avoid swimming in beaches for at least one day after heavy rain
• avoid drinking untreated water such as water from rivers or springs. If you need to drink untreated water, boiling it first will kill the Cryptosporidium
• avoid swallowing water when swimming if you can
• if you’ve had diarrhoea, avoid swimming for at least two weeks after it has resolved
• avoid sharing towels or linen for at least two weeks after diarrhoea has resolved
• avoid sharing, touching or preparing food that other people may eat for at least 48 hours after diarrhoea has resolved
• wash your hands with soap and water after going to the bathroom or before preparing food (Cryptosporidium is not killed by alcohol gels and sanitisers).

Not all cases of diarrhoea are due to cryptosporidiosis. There are many other causes of infectious gastroenteritis and because the vast majority of the time recovery is uneventful you don’t need to see a doctor unless very unwell. If you do suspect you may have cryptosporidiosis you can ask your doctor to refer you for a stool test.

Vincent Ho, Associate Professor and clinical academic gastroenterologist, Western Sydney University

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

What’s the difference? is a new editorial product that explains the similarities and differences between commonly confused health and medical terms, and why they matter.

The terms “shyness” and “social anxiety” are often used interchangeably because they both involve feeling uncomfortable in social situations.

However, feeling shy, or having a shy personality, is not the same as experiencing social anxiety (short for “social anxiety disorder”).

Here are some of the similarities and differences, and what the distinction means.

How are they similar?

It can be normal to feel nervous or even stressed in new social situations or when interacting with new people. And everyone differs in how comfortable they feel when interacting with others.

For people who are shy or socially anxious, social situations can be very uncomfortable, stressful or even threatening. There can be a strong desire to avoid these situations.

People who are shy or socially anxious may respond with “flight” (by withdrawing from the situation or avoiding it entirely), “freeze” (by detaching themselves or feeling disconnected from their body), or “fawn” (by trying to appease or placate others).

A complex interaction of biological and environmental factors is also thought to influence the development of shyness and social anxiety.

For example, both shy children and adults with social anxiety have neural circuits that respond strongly to stressful social situations, such as being excluded or left out.

People who are shy or socially anxious commonly report physical symptoms of stress in certain situations, or even when anticipating them. These include sweating, blushing, trembling, an increased heart rate or hyperventilation.

How are they different?

Social anxiety is a diagnosable mental health condition and is an example of an anxiety disorder.

For people who struggle with social anxiety, social situations – including social interactions, being observed and performing in front of others – trigger intense fear or anxiety about being judged, criticised or rejected.

To be diagnosed with social anxiety disorder, social anxiety needs to be persistent (lasting more than six months) and have a significant negative impact on important areas of life such as work, school, relationships, and identity or sense of self.

Many adults with social anxiety report feeling shy, timid and lacking in confidence when they were a child. However, not all shy children go on to develop social anxiety. Also, feeling shy does not necessarily mean a person meets the criteria for social anxiety disorder.

People vary in how shy or outgoing they are, depending on where they are, who they are with and how comfortable they feel in the situation. This is particularly true for children, who sometimes appear reserved and shy with strangers and peers, and outgoing with known and trusted adults.

Individual differences in temperament, personality traits, early childhood experiences, family upbringing and environment, and parenting style, can also influence the extent to which people feel shy across social situations.

However, people with social anxiety have overwhelming fears about embarrassing themselves or being negatively judged by others; they experience these fears consistently and across multiple social situations.

The intensity of this fear or anxiety often leads people to avoid situations. If avoiding a situation is not possible, they may engage in safety behaviours, such as looking at their phone, wearing sunglasses or rehearsing conversation topics.

The effect social anxiety can have on a person’s life can be far-reaching. It may include low self-esteem, breakdown of friendships or romantic relationships, difficulties pursuing and progressing in a career, and dropping out of study.

The impact this has on a person’s ability to lead a meaningful and fulfilling life, and the distress this causes, differentiates social anxiety from shyness.

Children can show similar signs or symptoms of social anxiety to adults. But they may also feel upset and teary, irritable, have temper tantrums, cling to their parents, or refuse to speak in certain situations.

If left untreated, social anxiety can set children and young people up for a future of missed opportunities, so early intervention is key. With professional and parental support, patience and guidance, children can be taught strategies to overcome social anxiety.

Why does the distinction matter?

Social anxiety disorder is a mental health condition that persists for people who do not receive adequate support or treatment.

Without treatment, it can lead to difficulties in education and at work, and in developing meaningful relationships.

Receiving a diagnosis of social anxiety disorder can be validating for some people as it recognises the level of distress and that its impact is more intense than shyness.

A diagnosis can also be an important first step in accessing appropriate, evidence-based treatment.

Different people have different support needs. However, clinical practice guidelines recommend cognitive-behavioural therapy (a kind of psychological therapy that teaches people practical coping skills). This is often used with exposure therapy (a kind of psychological therapy that helps people face their fears by breaking them down into a series of step-by-step activities). This combination is effective in-person, online and in brief treatments.

For more support or further reading

Online resources about social anxiety include:

• This Way Up’s online program for managing excessive shyness and fear of social situations
• Beyond Blue’s resources on social anxiety
• a guide to looking after yourself if you have social anxiety, from the Western Australian health department
• social anxiety online program for children and teens from the University of Queensland
• inroads, a self-guided online program for young adults who drink alcohol to manage their anxiety.

We thank the Black Dog Institute Lived Experience Advisory Network members for providing feedback and input for this article and our research.

Kayla Steele, Postdoctoral research fellow and clinical psychologist, UNSW Sydney and Jill Newby, Professor, NHMRC Emerging Leader & Clinical Psychologist, UNSW Sydney

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