A new study demonstrates for the first time how the Toxoplasma gondii parasite enters the brain to influence its host's behavior. This research was led by researchers from the Karolinska Institute and Uppsala University in Sweden publishes today in the Open Access journal PLOS Pathogens.
The Toxoplasma gondii parasite causes toxoplasmosis. The parasite is common and infects between 30 and 50 per cent of the global population. It also infects animals, especially domestic cats. Human infection is contracted by eating poorly cooked (infected) meat and handling cat feces. Toxoplasmosis first appears with mild flu-like symptoms in adults and otherwise healthy people before entering a chronic and dormant phase, which has previously been regarded as symptom-free. But when the immune system is weakened toxoplasmosis in the brain can be fatal. The fetus can be infected through the mother and because of this risk, pregnant women are recommended to avoid contact with cat litter boxes. Surprisingly, several studies in humans and mice have suggested that even in the dormant phase, the parasite can influence increasing risk taking and infected people show higher incidence of schizophrenia, anxiety and depression, which are broader public health concerns.
In their recent study Fuks et al. showed for the first time how the parasite enters the brain and increases the release of a neurotransmitter called GABA (gaba-Aminobutyric acid), that, amongst other effects, inhibits the sensation of fear and anxiety. In one laboratory experiment, human dendritic cells were infected with toxoplasma. After infection, the cells, which are a key component of the immune defense, began actively releasing GABA), In another experiment on live mice, the team was able to trace the movement of infected dendritic cells in the body after introducing the parasite into the brain, from where it spread and continued to affect the GABA system.
"For toxoplasma to make cells in the immune defense secrete GABA was as surprising as it was unexpected, and is very clever of the parasite," says Antonio Barragan, researcher at the Center for Infectious Medicine at Karolinska Institute and the Swedish Institute for Communicable Disease Control. "It would now be worth studying the links that exist between toxoplasmosis, the GABA systems and major public health threats."
Public Library of Science: http://www.plos.org
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
An innate ability some people have to manipulate their vocal frequency could be the key to sounding charismatic, according to new research.
Time-lapse imagery of scavengers tucking in proves that dead jellyfish aren't unpalatable after all, so can return nutrients to the sea's food webs
When bird pairs break up females often lay more eggs with a new partner, but the split can be disastrous for the male of the species
Spontaneous gene mutations, not ones inherited from parents, increase a child's risk of autism, scientists say. By comparing genes within families they've identified more than 100 suspects.
Slovenian archaeologist Ivan prajc is behind discovery of three significant ruins in the remote jungles of the Yucatán peninsula
Every year, Nikon selects the most artful, scientifically enlightening and skillfully produced images from thousands of submissions for its Small World microscope photography contest. Tomorrow, another set of impressive winners will be announced for the contest’s 40th year.
Seaview divers routinely cover 2 kilometers in a dive and generate 3,000 panoramic images in a day. Only a fraction of the best are uploaded to Google Street View.
Meeting sharks can be a moving experience, says photographer Jean-Marie Ghislain, who works to educate people on the plight of sharks around the world
From kraken to mermaids, some monsters are real—if you know how to look for them
Australia's Academy of Science says a government draft plan to protect the Great Barrier Reef will not prevent its decline.