Behavioral changes induced by Toxoplasma infection of rodents are highly specific to aversion of cat odors.

@article{citeulike:1555066, abstract = {The protozoan parasite Toxoplasma gondii blocks the innate aversion of rats for cat urine, instead producing an attraction to the pheromone; this may increase the likelihood of a cat predating a rat. This is thought to reflect adaptive, behavioral manipulation by Toxoplasma in that the parasite, although capable of infecting rats, reproduces sexually only in the gut of the cat. The "behavioral manipulation" hypothesis postulates that a parasite will specifically manipulate host behaviors essential for enhancing its own transmission. However, the neural circuits implicated in innate fear, anxiety, and learned fear all overlap considerably, raising the possibility that Toxoplasma may disrupt all of these nonspecifically. We investigated these conflicting predictions. In mice and rats, latent Toxoplasma infection converted the aversion to feline odors into attraction. Such loss of fear is remarkably specific, because infection did not diminish learned fear, anxiety-like behavior, olfaction, or nonaversive learning. These effects are associated with a tendency for parasite cysts to be more abundant in amygdalar structures than those found in other regions of the brain. By closely examining other types of behavioral patterns that were predicted to be altered we show that the behavioral effect of chronic Toxoplasma infection is highly specific. Overall, this study provides a strong argument in support of the behavioral manipulation hypothesis. Proximate mechanisms of such behavioral manipulations remain unknown, although a subtle tropism on part of the parasite remains a potent possibility.}, address = {Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA. ajaivyas@stanford.edu}, author = {Vyas, A. and Kim, S. K. and Giacomini, N. and Boothroyd, J. C. and Sapolsky, R. M. }, citeulike-article-id = {1555066}, doi = {10.1073/pnas.0608310104}, issn = {0027-8424}, journal = {Proc Natl Acad Sci U S A}, keywords = {cats, id, medicine, parasite, rats}, month = {April}, number = {15}, pages = {6442--6447}, posted-at = {2007-08-12 02:54:56}, priority = {4}, title = {Behavioral changes induced by Toxoplasma infection of rodents are highly specific to aversion of cat odors.}, url = {http://dx.doi.org/10.1073/pnas.0608310104}, volume = {104}, year = {2007} }

TY - JOUR ID - citeulike:1555066 L3 - citeulike-article-id:1555066 TI - Behavioral changes induced by Toxoplasma infection of rodents are highly specific to aversion of cat odors. JF - Proc Natl Acad Sci U S A VL - 104 IS - 15 SP - 6442 EP - 6447 AD - Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA. ajaivyas@stanford.edu SN - 0027-8424 N2 - The protozoan parasite Toxoplasma gondii blocks the innate aversion of rats for cat urine, instead producing an attraction to the pheromone; this may increase the likelihood of a cat predating a rat. This is thought to reflect adaptive, behavioral manipulation by Toxoplasma in that the parasite, although capable of infecting rats, reproduces sexually only in the gut of the cat. The "behavioral manipulation" hypothesis postulates that a parasite will specifically manipulate host behaviors essential for enhancing its own transmission. However, the neural circuits implicated in innate fear, anxiety, and learned fear all overlap considerably, raising the possibility that Toxoplasma may disrupt all of these nonspecifically. We investigated these conflicting predictions. In mice and rats, latent Toxoplasma infection converted the aversion to feline odors into attraction. Such loss of fear is remarkably specific, because infection did not diminish learned fear, anxiety-like behavior, olfaction, or nonaversive learning. These effects are associated with a tendency for parasite cysts to be more abundant in amygdalar structures than those found in other regions of the brain. By closely examining other types of behavioral patterns that were predicted to be altered we show that the behavioral effect of chronic Toxoplasma infection is highly specific. Overall, this study provides a strong argument in support of the behavioral manipulation hypothesis. Proximate mechanisms of such behavioral manipulations remain unknown, although a subtle tropism on part of the parasite remains a potent possibility. KW - cats KW - id KW - medicine KW - parasite KW - rats AU - Vyas, A AU - Kim, SK AU - Giacomini, N AU - Boothroyd, JC AU - Sapolsky, RM PY - 2007/04/10/ UR - http://dx.doi.org/10.1073/pnas.0608310104 ER -