Health: Schizophrenia may be linked to Bartonella, the bacteria behind cat scratch disease

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Schizophrenia may be associated with Bartonella, the bacteria behind ‘cat scratch disease’ that can be caught through the bites and scratches of infected felines.

Cats become infected with the bacteria through ticks and fleas, and transmission to humans can cause fatigue, headaches, fever and swollen lymph nodes.

Cat scratch disease was long thought to be short-lived, but the new findings suggest the infection may persist in some people.

US researchers tested the blood of both a small number of schizophrenia patients and healthy adults for evidence of Bartonella DNA.

They found that 12 of the 17 schizophrenia patients had Bartonella DNA in their blood, compared to just a single member of the 13-member control group.

This preliminary study was very limited in size and further research will need to be done to establish a clear link between Bartonella and schizophrenia.

However, the findings are suggestive and support the launch of follow-up studies “ strongly, ” the team said.

Schizophrenia may be associated with Bartonella, the bacteria behind 'cat scratch disease' that can be caught through bites (pictured) and scratches from infected felines (stock image)

Schizophrenia may be associated with Bartonella, the bacteria behind ‘cat scratch disease’ that can be caught through bites (pictured) and scratches from infected felines (stock image)

American researchers tested the blood of both a small number of patients with schizophrenia and healthy adults for evidence of Bartonella DNA.  Pictured: a hand with scratches from a cat's claws.  If the cat was infected with Bartonella, the person could get cat scratch disease

American researchers tested the blood of both a small number of patients with schizophrenia and healthy adults for evidence of Bartonella DNA.  Pictured: a hand with scratches from a cat's claws.  If the cat was infected with Bartonella, the person could get cat scratch disease

American researchers tested the blood of both a small number of patients with schizophrenia and healthy adults for evidence of Bartonella DNA. Pictured: a hand with scratches from a cat’s claws. If the cat was infected with Bartonella, the person could get cat scratch disease

“Researchers have been looking at the link between bacterial infection and neuropsychiatric conditions for some time,” said paper author 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 to date there is no conclusive evidence for a causal role of this parasite.

“So we decided to look at another feline-associated infectious agent, Bartonella, to see if there could be a link.”

“While there is an emerging understanding of neuropsychiatric diseases such as schizophrenia as disorders of brain networks, the question of the actual causes remains unanswered,” said paper author Flavio Frohlich.

“To our knowledge, this is the very first work to investigate a possible role for Bartonella in schizophrenia,” added the University of North Carolina psychiatrist.

In their small-scale study, the team enrolled 17 people with stable and medically treated cases of schizophrenia or schizoaffective disorder and a control group of 13 healthy adults, all of whom tested them twice weekly for Bartonella infection.

The team found that 12 of 17 patients with schizophrenia had Bartonella DNA in their blood, compared to just one member of the control group.

Both the patients and control groups had reported similar levels of pet ownership and exposure to fleas, which can also carry Bartonella.

Twelve of the 17 schizophrenia patients had DNA from Bartonella (shown in this artist's impression) in their blood - compared to just a single member of the 13-member control group

Twelve of the 17 schizophrenia patients had DNA from Bartonella (shown in this artist's impression) in their blood - compared to just a single member of the 13-member control group

Twelve of the 17 schizophrenia patients had DNA from Bartonella (shown in this artist’s impression) in their blood – compared to just a single member of the 13-member control group

“Bartonella ddPCR, a very new diagnostic technology, provides a more sensitive molecular test than we previously had access to,” said paper author and infectious disease expert 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 DNA in any of the participants, either in case or in control.’

“It is important to remember that our study failed to establish a causal relationship between Bartonella infection and schizophrenia by design,” said Professor Frohlich.

“However, we believe that this first observational study strongly supports the need for further research.”

Cats become infected with the bacteria through ticks and fleas and transmission to humans can cause fatigue, headaches, fever, swollen lymph nodes and lesions at bite sites (photo)

Cats become infected with the bacteria through ticks and fleas and transmission to humans can cause fatigue, headaches, fever, swollen lymph nodes and lesions at bite sites (photo)

Cats become infected with the bacteria through ticks and fleas and transmission to humans can cause fatigue, headaches, fever, swollen lymph nodes and lesions at bite sites (photo)

With their first study completed, the researchers are now planning a larger study to see if their preliminary results are indeed confirmed.

‘Many of these patients have been receiving care for years. What we are starting to see is a pattern – Bartonella can persist for a long time, ”said Dr. Breitschwerdt.

“For the subgroup of people who cannot eliminate the infection, the bacteria can cause chronic or progressive disease.”

The full findings of the study have been published in the journal Vector-borne and zoonotic diseases

SCHIZOPHRENIA EXPLAINED

Schizophrenia is a chronic and serious mental disorder that affects how a person thinks, feels, and behaves.

People with schizophrenia may seem to have lost touch with reality.

The cause of schizophrenia is not understood and is believed to be a mix of genetics (hereditary), brain chemistry abnormalities and / or possible viral infections and immune disorders.

Symptoms of schizophrenia usually start between the ages of 16 and 30. In rare cases, children also have schizophrenia.

The symptoms of schizophrenia fall into three categories: positive, negative, and cognitive.

Positive symptoms are disorders that are ‘added’ to the person’s personality and include:

  • Hallucinations
  • Delusions
  • Thought disturbances (unusual or dysfunctional ways of thinking)

Negative symptoms are abilities that have been ‘lost’ to the person’s personality and include:

  • Flat affect (reduced expression of emotions through facial expression or voice tone)
  • Decreased feelings of pleasure in everyday life
  • Difficulty starting and maintaining activities

Cognitive symptoms are changes in their memory or other aspects of thinking and include:

  • Problems focusing or paying attention
  • Problems with ‘working memory’
  • Poor ability to understand information and use it to make decisions

Figures suggest that about one percent of the world’s population suffers from schizophrenia, with about two million in the US.

SOURCE: National Institute of Mental Health