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Cat Parasite Linked to Likelihood of Alzheimer’s Disease

Journal of Parasitology – Toxoplasma gondii is a parasite that may not be a household name, yet it is considered one of the most prevalent pathogens in the world. The effects it has on the brain of unborn children keep pregnant women away from litterboxes, however, scientists suspect even more people should be cautious, as infection by the parasite may be tied to Alzheimer’s disease.

A study in the current issue of the Journal of Parasitology tested whether there was a link between chronic infection with the T. gondii parasite and Alzheimer’s disease, the most common form of dementia today. The study focused on mice, some that were infected with the parasite and others that were altered to create an Alzheimer’s disease model. The mice were then tested for behavioral and molecular changes.

The authors found that after infection with the parasite, mice had impaired learning and memory function, just as they would with Alzheimer’s disease. The infection also altered their brain chemistry compared to uninfected mice. In one group, the infection increased the likelihood of Alzheimer’s disease.

About one-third of people worldwide are suspected of having a T. gondii infection, and many more are at risk. This includes cat owners, who don’t wash their hands thoroughly after handling contaminated litter, and pregnant women, who can pass the infection to a child in the womb. Once infection occurs, the parasite moves to the brain. Symptoms can vary widely, with some people revealing no outward signs of infection and others becoming acutely ill and showing behavioral and body-chemical changes that mimic schizophrenia. However, because this chronic infection targets the brain, researchers have been investigating whether it could actually be a cause of Alzheimer’s disease, schizophrenia, or mood disorders as opposed to simply mimicking the signs of such illnesses.

Michael Sukhdeo, editor of the Journal of Parasitology says that it is highly plausible that T. gondii may be linked to Alzheimer’s disease, “given that the parasite likes to live in the brain. It is also of great public health concern with pregnant women, who are warned against cleaning cat litter for fear of infecting the fetus.”

The authors found that the parasite can affect the progression of Alzheimer’s disease in the brain of a mouse both directly and indirectly. If these findings were to hold true for human patients, the parasite may be a public health concern for newborns as well as adults.

FFull text of the article “Toxoplasma gondii Infection Potentiates Cognitive Impairments of Alzheimer’s Disease in the BALB/C Mice,” Journal of Parasitology, Vol. 102, No. 6, 2016, is now available here.


About Journal of Parasitology

The Journal of Parasitology is the official journal of the American Society of Parasitologists (ASP). The journal reports on all aspects of animal and human parasites, and is widely recognized for publishing content that has a long-term impact on the field of parasitology. The journal is intended for all with interests in basic or applied aspects of general, veterinary, medical parasitology, and epidemiology. For more information, visit us.

Media Contact:
Caitlyn Ziegler
Allen Press, Inc.
800/627-0326 ext. 410

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