As Dr. Moalem stated on page 107 in the chapter “Of Microbes and Men,” it is believed that T. gondii is “largely benign in humans.” While it is in most cases, it is not true for everyone. However, let’s focus on influences has on humans. Firstly, Dr. Moalem states that T. gondii may “trigger schizophrenia” is some. Additionally, he goes on to talk about how T. gondii can affect human behavior tendencies for those who are “more likely to be exposed to T. gondii.” For example, women become more materialistic and outgoing. They, in addition, have weaker relationships with friends and significant others. Men, on the other hand, are the opposite. They are poorly groomed, more independent, and more aggressive/rebellious. Relating to Big Idea #4 (Biological systems interact, and these systems and their interactions possess complex properties), use the internet, book, and previous knowledge learned in class to answer the following questions. Look into both E. Fuller Torrey’s (the man who made the claim on schizophrenia relating to T. gondii) and Professor Jaroslav Flegr’s (the man who made the claim on human behaviours relating to T. gondii) journal articles for guidance as well.
What is T. gondii? How is T. gondii accessible to humans? What is schizophrenia? Looking at the journal articles and the book itself, how is T. gondii and schizophrenia related? Additionally, how do you suppose T. gondii could have an affect on human behavior? Why does it cause two different types of behaviour (almost opposite of each other) for both males and females. Are there cases in which T. gondii doesn’t cause a behaviour change in humans? Use complete sentences to answer the previous question.
Noella James
noellajames@gmail.com
This comment has been removed by the author.
ReplyDeleteT. gondii is a parasite that can live in any warm-blooded animals. For humans, the illness is usually foodborne, but the immune system can usually fight off the infection. (http://www.cdc.gov/parasites/toxoplasmosis/) For example, helper T cells, when recognizing the foreign antigen presented by parasitic cells, can send different chemokines to alert special parasite-killing white blood cells, such as eosinophils, to arrive and fight off the threat. However, if the immune system is weakened by other pathogenic threats, or if the individual infected is pregnant, the individual might have a much more difficult time fighting off the parasite. While T. gondii can survive in most mammals, it can only reproduce in the intestines of cats. The T. gondii can spread via the expelling of oocysts from felines. (Oocysts are cysts containing the zygote form of a parasite) The oocysts can then be picked up by birds or rodents in their water supply. These oocysts can then be transported back to a feline when they consume the bird, or the oocysts can be picked up by animals that humans consume. Humans can even directly be infected by the oocysts from cat litter. (http://www.cdc.gov/parasites/toxoplasmosis/biology.html) Healthy adults that are infected with T. gondii, should show no symptoms. But if a pregnant woman gets infected, there can be serious complications for the child. The child may get diseases of the eyes and nervous system. (http://www.cdc.gov/parasites/toxoplasmosis/epi.html). T. gondii when exposed to rodents can change the way that the rodent will behave. The rodent will overtime become an easier prey for the cats; in essence the rodent is being manipulated by the parasite that lives inside of it, so that the parasite can be more easily spread amongst hosts, helping the parasite achieve its main goal of surviving and reproducing.Does this mean that T. gondii has a behavioral effect on humans as well? Professor Jaroslav Flegar questioned that humans and this parasite had an asymptomatic relationship, due to how T. gondii affects rodents. Flegar found in his studies (done with behavioral tests) that humans with T. gondii did exhibit traits very different than humans without T. gondii. The same chemical signals that T. gondii gives off to rodents, can have an effect on the humans. The different behavioral responses can be the reaction of the chemicals in the human body. (http://schizophreniabulletin.oxfordjournals.org/content/33/3/757.full) Professor Torrey found in his studies, that this change in behavior can also lead to psychotic symptoms very similar to the symptoms of schizophrenia. Schizophrenia is a mental disorder where the person does not have the normal thought process and can have abnormal emotional responses. He finds later in his study that by inhibiting the replication of T. gondii cells, he may be able treat schizophrenia. (http://wwwnc.cdc.gov/eid/article/9/11/03-0143_article.htm) According to Dr. Moalem, if T. gondii does affect human behavior, it is all accidental effect from the chemicals meant to manipulate rodents that change the behaviors of the humans. So yes, there could be cases where T. gondii does not affect human behavior.
ReplyDeleteLily Barghi – lbarghi4@students.d125.org