This subproject is one of many research subprojects utilizing theresources provided by a Center grant funded by NIH/NCRR. The subproject andinvestigator (PI) may have received primary funding from another NIH source,and thus could be represented in other CRISP entries. The institution listed isfor the Center, which is not necessarily the institution for the investigator.BACKGROUND: Toxoplasma gondii is a protozoan microbial parasite that infects a wide range of wild and domestic animals and can be transmitted to human beings. Toxoplasma gondii is an important cause of encephalopathy and death in immunocompromised persons. Mice chronically infected with T. gondii exhibit selective increases in CNS dopamine concentrations (Stibbs, 1985). Increases in CNS dopamine are associated with psychosis in humans, and Obsessive Compulsive Disorder (OCD) like ritualistic behavior in rodents (Eilam and Szechtman, 2005). Interestingly, dopamine activity can also be associated with personality traits in humans, particularly 'novelty seeking' (Cloninger, 1998; Hansenne et al., 2002). Additionally, T. gondii infection in humans can be associated with personality changes (Flegr and Hrdy, 1994; Flegr et al., 1996; Flegr and Havlicek, 1999; Flegr et al., 2000; Novotna et al., 2005), including decreased novelty seeking (Flegr et al., 2003; Novotna et al., 2005).RESEARCH PLAN: We propose to test the association between toxoplasmosis gondii exposure and a specific behavioral phenotype, 'hoarding behavior' and low 'novelty seeking.' Because cats and rodents are common host for toxoplasmosis gondii we plan to make the association of lifetime exposure to cats and rats to Toxoplasmosis gondii infection.METHODS: We will examine the relationship between infection to Toxoplasmosis gondii, hoarding behavior, novelty seeking behavior, and lifetime exposure to household cats or laboratory rats, 80 healthcare professionals who do not have baseline Obsessive Compulsive Disorder. Healthcare professionals are not likely to have significant mental or physical comorbidities. Nevertheless, the office setting provides a personal space in which there is little policing of incipient hoarding behavior. Individual office spaces will be blindly rated for level of hoarding. Subjects will be evaluated for novelty seeking behavior, surveyed for lifetime exposure to cats/laboratory rats, and have serum Toxoplasmosis gondii antibodies drawn as an indication of prior exposure to the parasite.CLINICAL
Pathological horading, (i.e., 'syllogamania', sometimes also called the 'Diogenes Syndrome'), is characterized by domestic squalor, loss of insight, and social withdrawal (Clark, Manikur amp; Gray, 1975; Cooney amp; Hamid, 1995). Affected individuals amass huge quantities of apparently useless and unused articles, including both new and old items, newspapers and magazines, used food containers, bedding, and other useless rubbish. In extreme cases, the living conditions of these persons are filthy and neglected on the exterior. Homes may lack utilities. The interior is often filled with rubbish and clutter to the point of being a health hazard to the person. Diogenes cases are often found living in unsanitary conditions. The living environment may contain numerous pets, insect or rodent infestations, and occasionally human and animal excrement, (i.e., an environment that is conducive to the interspecies transmission of T. gondii) (Patronek, 1999). A majority of these persons also suffer from poor health maintenance including malnutrition and anemia. The Diogenes syndrome is an important public health problem. Cooney amp; Hamid (1995) estimate an annual incidence of the Diogenes Syndrome at 5 per 10,000 persons aged over 60 years. This may be an underestimate, as the available studies are restricted persons who are known to health care providers. Social service providers estimate 1,000 active cases in Manhatten alone, (i.e., a prevalence of 4/10,000) (Ron Alford www.theplan.com; personal communication). Diogenes cases may comprise 25% of Bexar County Adult Protective Services; caseload (personal communication). In this pilot study, we propose to test the association between toxoplasmosis gondii exposure and hoarding behavior. If such an association can be demonstrated, there would be important implications. First, it would demonstrate the capacity of CNS parasites to alter human host behavior in the absence of clinical disease. Second, it would demonstrate the potential for a wide variety of currently unexplained behavioral disorders to be the product of parasitic manipulation. Third, it would offer the potential of specific anti-microbial treatments for an important public health problem.
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