During a camping and hiking expedition in the Ice Age National Scenic Trail at Hartman Creek State ...

Answer: Acute Lyme disease symptoms include backache, the chills, headache, and overall fatigue. Chemicals (e.g., DEET) that repel insects such as deer ticks should be applied all over the individual's body. Deer ticks are also attracted to white from the white-tailed deer they infect, so dark-colored clothing can also minimize B. borgdorferi infections. Long protective clothing should also be worn such as socks being tucked into boots and wearing snug collars and cuffs.

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Answer: When an infectious agent invades a cell that is not necessary for its life cycle, it is considered to be infecting an accidental host. For example, Yersinia pestis has no life cycle dependency on humans and normally causes disease in rodents. However it is possible for Y. pestis to infect a human (the accidental host). Answers could include many other examples from the chapter, such as hantaviruses.

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Answer: Hantaviruses usually cause viral hemorrhagic fevers in the United States. Bleeding (or hemorrhaging) is rarely the cause of death for this disease; it is instead usually organ system failure caused by hantavirus that kills an individual. Vascular systems of organs are disrupted by the pathogen that also decreases oxygen and waste transport as well as temperature control.

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Answer: Plague is a zoonosis of rodents that is transmitted between hosts by the rat flea Xenopsylla cheopis. Before the host and vector of the plague were known, humans were accidental hosts that were infected in crowded areas where humans and rodents lived close together (such as rat-infested ships, crowded cities, or military encampments). Control of rodent populations has stopped the spread of plague to humans from the natural host/vector of the rat and rat flea. The causative agent of plague, Yersinia pestis, is still present in natural populations of rodents and has NOT been eradicated. If a human is infected with Y. pestis the infection can be treated with common antibiotics. No vaccine is warranted, because the disease is now very rare in humans and can be treated successfully.

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Answer: The rabies virus propagates inside the brain, where once in high numbers can cause disease. This is an important consideration, because if a rabid dog bites an individual on the toe, the virus will likely have a longer incubation time than if the infection site was on his/her shoulder (nearer to the brain).