Schizophrenia may be linked to Bartonella, the bacterium behind “cat scratch” disease, which can be contracted through bites and scratches from infected cats.
Cats are infected with the bacteria through ticks and fleas, and transmission to humans can cause tiredness, headaches, fever and enlarged lymph nodes.
Cat scratch disease has long been thought to be short-lived, but new findings suggest that in some people the infection may persist.
Researchers from the United States tested the blood of a small number of schizophrenic patients and healthy adults for evidence of Bartonella’s DNA.
They found that 12 of the 17 schizophrenic patients had Bartonella DNA in their blood, compared to just a single member of the group of 13 controls.
This preliminary study was very limited in size and more research will need to be done to establish a definitive link between Bartonella and schizophrenia.
However, the findings are suggestive and ‘strongly support’ the launch of follow-up studies, the team commented.
Schizophrenia may be linked to Bartonella, the bacterium behind the “cat scratch” disease that can be contracted through bites (photo) and scratches from infected cats (stock image)
American researchers tested the blood of a small number of schizophrenic patients and healthy adults for evidence of Bartonella’s DNA. In the photo: a hand with scratches from a cat’s claws. If the cat was infected with Bartonella, the person could develop cat scratch disease
“Researchers have been looking at the connection between bacterial infection and neuropsychiatric illness for some time,” said the author of the article and veterinary researcher Erin Lashnits of the University of Wisconsin.
“Specifically, there is research suggesting that cat ownership is associated with schizophrenia due to the zoonotic parasite Toxoplasma gondii, but so far there has been no conclusive evidence to support a causative role for this parasite.
‘So we decided to look at another cat-associated infectious agent, Bartonella, to see if there could be a connection.’
“While there is an emerging understanding of neuropsychiatric diseases, such as schizophrenia, such as disorders of the brain networks, the question of the true causes remains unanswered,” said the article’s author, Flavio Frohlich.
“As far as we know, this is the first paper that examines Bartonella’s potential role in schizophrenia,” added the University of North Carolina psychiatrist.
In their small-scale study, the team enrolled 17 people with stable and clinically treated cases of schizophrenia or schizoaffective disorder and a control group of 13 healthy adults, all of whom were tested twice in one week for Bartonella infection.
The team found that 12 of the 17 schizophrenic patients had Bartonella DNA in their blood, compared to just one member of the control group.
Both patients and control groups reported similar levels of pet ownership and exposure to fleas, which can also carry Bartonella.
Twelve of the 17 schizophrenic patients had Bartonella’s DNA (pictured in this artist’s print) in their blood – compared to just a single member of the 13 strong control group
“Bartonella ddPCR, a very new diagnostic technology, provides a more sensitive molecular test than before,” said article author and infectious disease specialist Ed Breitschwerdt of North Carolina State University.
‘If we had not used ddPCR to test this cohort of individuals, we would not have found Bartonella’s DNA in any of the participants, either case or control.’
“It is important to remember that our study was not designed to demonstrate a causal link between Bartonella infection and schizophrenia,” said Professor Frohlich.
‘However, we believe that this initial observational study strongly supports the need for follow-up research.’
Cats are infected with the bacteria through ticks and fleas and transmission to humans can cause tiredness, headaches, fever, swollen lymph nodes and lesions at the bite sites (photo)
In fact, with the initial study completed, the researchers are now planning a larger study to see if their preliminary results are actually confirmed.
“Many of these patients have been treated for years. What we are starting to see is a pattern – Bartonella can persist for a long time, ‘said Dr. Breitschwerdt.
“For the subset of people who are unable to eliminate the infection, the bacteria can cause chronic or progressive illnesses.”
The full results of the study were published in the journal Vector Borne and Zoonotic Diseases.