Mumps is not an emerging disease—Hippocrates described the disease in the 5th century B.C.—it has been present in the human population for thousands of years. Emerging infectious diseases are those whose incidence in humans have either increased in the past 30 years or threaten to increase in the near future. They arise from movement into areas where humans have not ventured before, and can also be diseases that move from certain areas of the world to places where the diseases have not been before.
Correct Answer: Mumps
All three diseases have appeared in the past 40 years. Only Legionnaires disease is bacterial, only AIDS is viral, Creutzfeldt–Jacob disease is not caused by a microorganism, and Legionnaires disease has no latency period.
Correct Answer: They have all emerged in the past 40 years
Nipah virus originated in pigs.
Correct Answer: Pigs
SARS originated in Hong Kong.
Correct Answer: Hong Kong
Hantavirus disease originated in South America.
Correct Answer: South America
Spongiform encephalopathy originated in New Guinea.
Correct Answer: New Guinea
HIV originated in Africa.
Correct Answer: Africa
MERS originated in the Middle East.
Correct Answer: Middle East
Hantavirus has not yet developed the ability to be transmitted from human to human. Influenza, HIV and SARS are all transmissible among humans.
Correct Answer: Hantavirus
SARS stands for Severe Acute Respiratory Disease.
Correct Answer: Respiratory system
Most infected people are asymptomatic unless the infection causes an invasive neurological disease called West Nile fever, which occurs in 20–30% of those infected.
Correct Answer: Nervous system
Mosquitos are the vectors and birds are the primary hosts. Humans and animals such as horses can be infected by mosquitoes carrying the virus.
Correct Answer: Birds
The virulence of the infection depends on the virulence of the virus, the route of exposure, the viral load, and the competence of the host defence.
Correct Answer: All of the choices
Viral hemorrhagic fever infections are associated with fever, muscle ache, flushing, and the appearance of rashes.
Correct Answer: All of the choices
The influenza virus contains eight segments of RNA.
Correct Answer: Eight segments of RNA
Global urbanization encompasses the increase in densely populated settlements coupled with poverty, social upheaval, air travel, long-distance trade, technological development, land clearance, and climate changes. All these factors are contributing to the emergence and re-emergence of dangerous diseases that have the potential to spread more quickly than ever before.
Mutation of the hantavirus was not the cause of the outbreak. A very rainy summer led to a large dropping of pine nuts, which in turn produced a large population of deer mice, and thus a large reservoir for the virus.
Correct Answer: Mutation of the hantavirus
Latency has nothing to do with infectivity and becoming latent would not enable a virus to infect humans. Mutation, genetic rearrangement, and genetic re-assortment can all result in viruses with new biological properties such as the ability to infect human cells. Mutations occur every time a virus is replicated because viral polymerases make mistakes (especially for viruses with RNA genomes). In recombination, genetic material from a host cell is packaged into a virus. Viral genes can be re-ordered and/or new genes obtained from another virus by re-assortment.
Correct Answer: They become latent
SARS is a respiratory disease and is transmitted by droplets.
Correct Answer: Droplets
Mosquitoes transmit West Nile fever.
Correct Answer: Mosquito
Viral hemorrhagic fever is transmitted from person to person by contact with body fluids, usually blood. It is transmitted from animals to humans by humans eating bush meat.
Correct Answer: Body fluids, bush meat
Dengue fever is transmitted by mosquito bite.
Mad cow disease (BSE) was caused by material from dead sheep being included in cattle feed. BSE has also been seen in humans and is strongly linked to the consumption of infected bovine tissues.
Correct Answer: Food contamination
The virulence of influenza is affected by the health of the host. It is not affected by its ability to integrate into the host genome or any factors relating to DNA as the influenza genome contains only RNA.
Correct Answer: The health of the host
The two viruses have different hemagglutinins (H1 and H5). They have the same neuraminidase (both N1), can both infect humans, and are both currently a concern for public health.
Correct Answer: They have different hemagglutinins
Infectious prions are proteins that become folded improperly and then cause normal prions to fold improperly.
Correct Answer: Abnormal proteins
Transmissible spongiform encephalopathy comes in five forms in humans, but all have the same general characteristics: long incubation periods, spongiform defects in brain tissue, and plaque deposits in the brain.
Correct Answer: All of the choices except fever
Influenza outbreaks occur yearly and an outbreak could be expected in winter in the absence of biological weapons. On the other hand an increased incidence of smallpox in Seattle, Washington, a sudden upsurge of severe encephalitis, an increased number of emergency calls about infectious diseases, and an outbreak of systemic anthrax are each suggestive of a bioweapon attack.
Correct Answer: Outbreak of influenza in local schools in December