The Black Plague has killed millions of humans over the course of history, yet we do not vaccinate against this disease. Why is this and how is the disease controlled in modern human populations?
What will be an ideal response?
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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True or false: When two populations have undergone allopatric speciation long enough to be unable to produce fertile offspring, then they are different enough to be considered two different species
A. true B. false
Substitution of one base pair for another in a coding region of a gene can result in a ____ mutation where a codon
specifying an amino acid is changed to a stop codon.
a. missense b. chromosomal c. frameshift d. silent e. nonsense
In an effort to determine the mechanism of neuronal signaling, Otto Loewi isolated ____
a. frog hearts b. frog brains c. rat hearts d. rat brains e. rat vagus nerve
Which statement is not true about the urinary microbiome?
A) Shifts in microbiome composition may be associated with physiological concerns such as incontinence. B) Most species can be cultivated using standard laboratory techniques. C) The most consistently detected species are Lactobacillus and Streptococcus. D) The species composition is consistent throughout the urinary system, across the lifespan or from person to person. E) The healthy urinary tract was believed to be sterile until molecular methods of analysis became available.