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How common infection carried through cat faeces can affect daily human behaviour
A very common parasite found in billions of people around the world – including 20 per cent of Australians – can affect mental health and reaction times, even leading to more car crashes.
Toxoplasmosis is often carried in faeces of cats after eating a mouse, as well as in contaminated raw meat, and can be easily passed onto humans.
Once in the body, the parasite can then affect a person's daily behaviour.
It does not cause serious health risks to the average healthy person, but previous research has shown the infection is creating 'havoc' on people's dopamine levels, leading to a reduction in self-control, making more impulsive and high-risk decisions, and being impatient.
Dr Michele Garagnani from the University of Melbourne told those infected are two per cent more likely to be involved in a car crash.
'Our study suggests... people take more risks, are less patient, have less self-control and are more likely to start entrepreneurial decisions, like companies and start ups that turn out to be risky or not founded so they fail (or) are actually not successful,' the senior lecturer said.
'All the studies have shown that people with toxoplasmosis are more likely to feel anxious, to be depressed and have more mental health issues.'
There is no cure for toxoplasmosis and was once only detectable by blood or saliva swabs.
However, Dr Garagnani and his team – consisting of Carlos Alós-Ferrer from Lancaster University in the UK and Anja Achtziger from Zeppelin University in Germany – have created a new online test for people around the world to check if they are infected.
The 'simple' test involves assessing a person's reaction time.
A subject is placed in front of a computer or similar device where they are asked to focus on the screen for two minutes.
In that time the person must respond, for example, to the changing of colours, by pushing a button as quickly as possible.
'What we measure is both how quickly they react and how much they can sustain attention to a task,' Dr Garagnani told
To confirm the validity of the new testing tool, the research team carried out head-to-head clinical trials and compared it to blood tests.
The study found just under 80 participants had their reaction times analysed with RhD-negative blood types, which can slow a person's response by less than one second.
The online test has a 97 per cent accuracy rate, according to research published in April.
A larger study was then completed with 1,010 subjects who were then asked questions about their life, as well as employment and income.
The results showed 10 per cent of people 'deemed' with toxoplasmosis are more likely to be unemployed and on average earned less than those who were not infected.
'We also found that those who were deemed infected were more likely to smoke, drink alcohol and experience mental health problems,' Dr Garagnani said.
The test is not aimed to replace medical testing of toxoplasmosis but is hoped to allow more people to check whether they have the infection on a larger and cheaper scale.
The senior lecturer at the University of Melbourne stressed people infected with toxoplasmosis cannot feel it in their daily lives and the effects are 'very small'.
Dr Garagnani added the infection is a concern for individuals with weak immune systems, those with HIV and pregnant women as it can lead to serious health problems for the baby.
The World Health Organisation (WHO) had previously labelled it as 'one of the most neglected parasitic infections'.
But WHO recently provided an update to be 'less cautious' of it due to the rise in tuberculosis, 'the world's top infectious killer', which claims 4,500 lives and sees 30,000 people fall ill each day.
'They are still considering it as a neglected parasitic infection. It's insidious and growing instead of going down in the world population, which is alarming,' Dr Garagnani said.
'But it's an infection which has no medical symptoms during the lifelong part of the patient so it's less prevalent and less concerning than other sicknesses.'
