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Introduction There are two types of bacteria that cause Typhus, Rickettsia Typhi and Rickettsia Prowazekii. The form of Typhus depends on which type of bacteria has entered the body and caused the infection. Rickettsia Typhi causes Murine or Endemic Typhus. Endemic Typhus is unusual in the United States. When it is found, its usually seen in areas with poor hygiene and where the temperature is cold. Endemic typhus is sometimes called "jail fever." Murine Typhus typically occurs in the southeastern United States, often during the summer and fall. Risk factors for Murine Typhus include exposure to rat fleas or rat feces. Rickettsia Prowazekii causes both Epidemic Typhus and Brill-Zinsser disease. Brill-Zinsser disease is a far more mild form of Epidemic Typhus. It occurs when the disease re-activates in a person who was previously infected. It is more common in the elderly. Lice and fleas of flying squirrels spread the bacteria. There is no commercially available vaccine against either Endemic or E pidemic typhus. The name given the disease comes from the ancient Greek Typhus meaning smoky or hazy, denoting the condition of mind into which the victim soon lapses after developing his or her first symptoms. Symptoms of Murine or Endemic Typhus may include abdominal pain, backache, raging red rashes, an extremely high fever, hacking followed by a dry cough, headaches, nausea, vomiting and/or joint and muscle pain. Symptoms of Epidemic Typhus may include chills, confusion, Low blood pressure, stupor and/or sensitivity to light. Blood tests may show a low white blood cell count, anemia and low platelets. They may also show a high level of Typhus antibodies, low levels of albumin, low sodium levels and high liver enzymes. Typhus is often c... ...s of Typhus are limited, but the disease has the potential to re-emerge. For example, in Burundi, Africa refugee camps were afflicted in 1997-1998, when about half a million people received the illness. In China in 1999, more than five thousand six hundred people were afflicted following an earthquake. They were forced to live in poor, cold conditions making it the ideal place for a new breakout. In my opinion the United States should entirely rid itself of this disease, including all of the samples held in government labs to preserve as deadly war weapons. The government should also take necessary precaution all over the United States especially in shelters, habitually running tests and routinely ensuring the sanitization of shelters during a natural disaster. These preventive measures will almost guarantee the extermination of the disease in America all together.

Evaluation of Evolutionary Theory of Altruism and the Role of Genes-a Modern View Essay

Evolutionary theory holds that organisms with the strongest genes for survival and reproduction do, in fact, survive and reproduce most successfully. They thus multiply their genes most widely, spreading the advantageous genes through whole populations. Ceaseless repetitions of the process can gradually transform species into totally new ones. Such a world seems to have no place for self-sacrificing types, who presumably couldn’t spread their genes very far. Several competing theories attempt to solve the puzzle. One is that groups with cooperative members out compete groups with selfish ones, and thus spread their niceness genes, in a scaled-up version of the process by which genetically favored individuals trump other individuals. Variants of this notion have gained popularity in the past decade, although it fell from favor earlier, as it has some trouble explaining how altruism got a foothold in the first place. The origin of altruism and cooperation is an enigma because evolutionary theory seems to predict such behavior should be rare or nonexistent. Yet some forms of altruism, conscious or not, are widely documented in creatures as humble as insects and bacteria. Evolutionary theory attempts to explain the evolution of aiding others in two general ways: 1. It argues that genes favoring altruism can spread in future generations if their costs to altruists’ personal reproductive success is outweighed by the benefits in reproductive success of altruists’ relatives carrying copies of the same genes (‘kin selection’). The ratio of these indirect benefits through relatives, versus costs to oneself, needs to be greater the less closely the altruist is related to those helped – i. . , the lower the likelihood the altruist will be helping copies of their genes in the other. 2. It proposes that genes favoring altruism could spread if the altruism is sufficiently reciprocated (‘reciprocal altruism’) (Axelrod, R. & Hamilton, 1981). Biological Altruism versus Psychological Altruism Charles Darwin theorized that all species behave in ways that increase their chances for survival. Often, this survival instinct expresses itself as selfish behavior. Humans (and some animals), however, frequently ignore their personal interests and help others—a behavior called altruism. In volutionary biology, an organism is said to behave altruistically when its behavior benefits other organisms, at a cost to itself. The costs and benefits are measured in terms of reproductive fitness, or expected number of offspring. So by behaving altruistically, an organism reduces the number of offspring it is likely to produce itself, but boosts the number that other organisms are likely to produce. This biological notion of altruism is not identical to the everyday concept. In everyday parlance, an action would only be called ‘altruistic’ if it was done with the conscious intention of helping another. But in the biological sense there is no such requirement. Indeed, some of the most interesting examples of biological altruism are found among creatures that are not capable of conscious thought at all, e. g. insects. Altruistic behavior is common throughout the animal kingdom, particularly in species with complex social structures. For example, Vervet monkeys give alarm calls to warn fellow monkeys of the presence of predators, even though in doing so they attract attention to themselves, increasing their personal chance of being attacked. In social insect colonies (ants, wasps, bees and termites), sterile workers devote their whole lives to caring for the queen, constructing and protecting the nest, foraging for food, and tending the larvae. Such behavior is maximally altruistic: sterile workers obviously do not leave any offspring of their own — so have personal fitness of zero — but their actions greatly assist the reproductive efforts of the queen. Human altruism goes far beyond that which has been observed in the animal world. Among animals, fitness-reducing acts that confer fitness benefits on other individuals are largely restricted to kin groups (Trivers, 1971)(Axelrod & Hamilton, 1981). Where human behavior is concerned, the distinction between biological altruism, defined in terms of fitness consequences, and ‘real’ altruism, defined in terms of the agent’s conscious intentions to help others, does make sense. (Sometimes the label ‘psychological altruism’ is used instead of ‘real’ altruism. ) What is the relationship between these two concepts? They appear to be independent in both directions ( Sober, 1994). An action performed with the conscious intention of helping another human being may not affect their biological fitness at all, so would not count as altruistic in the biological sense. Most often, evolutionary psychologists explain the presence of social behavior like altruism in humans and other animals by reference to kin selection. Kin selection is the idea that natural selective pressures can favor a gene if it provides a trait that makes one’s relatives more likely to survive because that relative likely carries many of the same ( Dawkins, 1976) . Ultimately, I tend to find arguments for kin selection unconvincing for a whole host of reasons, among them: There’s seldom any consideration of the neural mechanisms that might be responsible, only the assumption that the ‘gene’ will cause altruistic behavior if it is favorable to the gene’s transmission and the most recent findings with the function of neurotransmitters like dopamine, serotonin and norepinepinephrine along with others prove there is no validity to kin selection and giving importance to individual affect and emotions including the feeling of euphoria in being altruist. ) An inability to explain why, if natural selection cares about our close relatives so much, our ‘altruism gene’ couldn’t be much more selective about who we feel altruistic about . ) The kin selection perspective tends to take an adaptationist view of natural selection, assuming that organic variation can easily produce candidate ‘adaptations’ to suit any environment and that all traits of an organism are necessarily adaptive (when, in fact, it’s a whole organism that is selected, not each individual trait, and traits are often connected genetically so that selection might be acting on another trait produced by the same gene) (Haldane , 1955). ) The problem of how closely related we need to be to kin for our altruism to really be a selective advantage if we are in competition with each other is frightening (Goldschmidt, 2006). The evolutionary process can generate behaviors that can be experienced in the evolutionary process but whose meaning can be completely detached from its original biological motivation. Let’s say that the evolutionary process produced a set of prompts in females, say big breast, which at the time were a sign of a woman’s ability to produce more milk for her babies (more kids they can produce and feed, the more genes will propagate, so men instinctively desire to want to mate with these females ). Lets now imagine that these females became sterile and the obsession for big breast had nothing to do with its original motivation. Taking from such observations we can say that a behavior which probably has been natural selection in the evolutionary process as Darwinian view suggests. However the same behavior may develop new motivations and may lose original evolutionary purpose altogether. For instance, it is entirely possible that pleasurable sex originated because organisms that â€Å"felt good† having sex had more of it and thus passed on more genes. Sex today serves entirely different role and in most cases is entirely unrelated to childbearing in humans. To trace altruistic behaviors in humans to evolutionary history based entirely on Darwinian concepts of reproductive success does not grab the trends in its entirety. It is possible that throughout the course of evolution certain nervous systems bound tightly with others for reproductive success reasons. However, it should be kept in mind that altruism is a set of behavioral concepts that originated in the things we can study and use as objects of exploration. True altruism can likely be a rewarding behavior that has little to do with its original biological altruism. Certain behaviors which give a greater chance of propagating our genes are likely to make us feel good so that people who feel good about such actions may have more offsprings. If a mother felt good about saving her kid, it is possible her brain is organized in a way that she feels good saving another kid who is not hers. However, we can say nothing about the question of why it makes us feel good, unless we undertake the task of finding the mechanism of both the biological evolutionary reasons as well as cultural components which caused the changes in the brain. The brain is structured in such a way that the feeling of compassion can be felt within its manifestation (limbic system, prefrontal cortex along with neurotransmitters dopamine, serotonin and norepinephrine)(Moore, 1984). We can say that there are lot of levels of organization between original evolutionary purpose and its eventual expression. Some of the most fundamental questions concerning evolutionary origins of altruism and selfishness need to be dealt with a multifactorial approach. Experimental evidence indicates that human altruism is a powerful force and is unique in the animal world. However, there is much individual heterogeneity among altruists . Current gene-based evolutionary theories cannot explain all important patterns of human altruism, pointing towards the importance of both theories of cultural evolution as well as gene–culture co-evolution. For evolutionary scientists, altruism is one of the great mysteries: it feels good, is linked to better mental and physical health, and is intrinsic to who we are, yet no one can quite explain how it evolved. The Feel-Good Chemicals and Altruism Now a new study suggests that altruism may be partly guided by genes that regulate the neurotransmitter dopamine — the one linked to craving, pleasure, and reward. Dopamine, referred to as a neurotransmitter in the brain’s reward mechanism, can be artificially released at very high levels by drugs such as heroin and cocaine, leading to euphoria. If altruism operates along the same lines, it would mean that the altruist gets the same feeling, albeit at much lower volume, as a cocaine user. The feeling becomes an incentive to help others again. Dopamine is widespread in the brain as well as the rest of the nervous system and plays a very important role in pleasure, love, libido, motivation, salience and integration of thoughts and feelings. This neurotransmitter plays a critical role in the control of movement. It has a stimulating effect on the heart, the circulation, the rate of metabolism, and is able to mobilize many of the body’s energy reserves. It helps to modulate brain activity, control coordination and movement, and regulate the flow of information to different areas of the brain. Dopamine is believed to release chemicals that allow us to feel pleasure (e. g. , endorphins). A massive disturbance of dopamine regulation in the brain can result in a person no longer being able to respond emotionally or express his or her feelings in an appropriate way (e. g. , schizophrenia). Our brains release favorable hits of dopamine when we engage in selfless behavior. Some individuals may be more genetically predisposed to altruism than others and that could be based on individual neurochemistry. This can be explained with the evidence from neuroscience. It’s said that altruism results in elevated serotonin levels as well. Serotonin happens to be the most widely studied neurotransmitter since it helps regulate a vast range of psychological and biological functions. Serotonin (5-hydroxytryptamine or 5-HT) was first identified in 1948. The wide extent of psychological functions regulated by serotonin involves mood, anxiety, arousal, aggression, impulse control, and thinking abilities. Other brain chemicals, such as dopamine and norepinephrine, also influence mood and arousal along with serotonin. It is said that altruism results in elevated serotonin levels. Serotonin is a neurotransmitter and also a neuromodulator for dopamine. It can mobilize the energy reserve of the body and aid in maintaining dopamine function in brain circuits of mood and thought; mesocortical and mesolimbic pathways. Dopamine has 5 receptors and subsets of dopamine genes vary in the general population, and the study finds that a specific, common subtype is highly linked to altruistic behavior. The research, conducted at Hebrew University and other centers, was published in the journal Molecular Psychiatry in 2005. Psychologists and geneticists looked at 354 families with more than one child, measuring the individuals’ tendencies to ignore their own needs and serve the needs of others — a trait associated within dopamine genes. They then analyzed the individuals’ dopamine receptors for well-known variations, or genotypes. Their fascinating findings: the most common genetic subtype — known as the D4. 4 — was significantly linked to altruistic behavior, regardless of whether the receiver was a relative. But in general, say the scientists, this gives us the first hard evidence that many of us are indeed â€Å"hardwired† for giving. It may be that generosity feels good because it is rewarded by spikes in dopamine. The scientists even speculate that further research could reveal variations in dopamine genes that favor generosity to kin, and others that favor giving to all and thus these neurotransmitter studies give us latest information regarding both an excellent counter-argument to the ‘selfish gene’ hypothesis as well as a much more persuasive account of the possible evolutionary origins of altruism than the typical explanation like kin selection (Neimark, 2006).

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