Mastering Micro Test 4

Which of the following explains why treatment of symptomatic tetanus requires an antitoxin and an antibiotic?

Because C. tetani bacteria excrete tetanus toxin, it is important to neutralize the toxin while also killing the bacteria that are producing more.

In the last segment of the animation, how many regions of the world experience the pandemic during April of year four?

Five

Lyme disease is caused by ____________ and is transmitted by __________.

B. burgdorferi; Ixodes

In the last segment of the animation, when does the first epidemic occur?

January of year three

Which of the following could be true of tuberculosis of the kidney?

The disease could be subsequent to a reactivated latent infection. The disease could be subsequent to a normal primary infection. The patient would likely be infected with MDR TB or XDR TB. The patient would likely have a positive skin test.

In the sixth segment of the animation, why is the disease epidemic in North America?

The disease occurs at a higher rate than what would normally be expected in this region.

How can insects passively carry pathogens

a fly may carry typhoid or dysentery from a host's feces to the food of another person

An animal disease transmitted to humans by direct contact, inhalation of aerosols, or bites is called __________.

a zoonosis

One group of medications used to treat HIV infections is the reverse transcriptase inhibitors. There are two types of these medications, nucleoside reverse transcriptase inhibitors (like AZT) and non-nucleoside reverse transcriptase inhibitors. AZT resembles thymine and is inserted into DNA during replication, leading to the termination of replication. Non-nucleoside reverse transcriptase inhibitors bind to reverse transcriptase and inhibit it in that manner. Non-nucleoside reverse transcriptase inhibitors tend to have fewer side effects. Which of the following best describes why this is the case?

Nucleoside reverse transcriptase inhibitors may interfere with DNA replication by the host, not just by the virus.

The emergent H5N1 strain of avian influenza can occasionally be transmitted from birds to humans with a resulting 60% mortality rate (compared with a 2.5% mortality rate for the 1918 pandemic influenza). In 2012, after a single dead chicken in a wholesale market in Hong Kong tested positive for H5N1, all 17,000 chickens in the market and surrounding area were culled. This was an attempt to__________.

eliminate a reservoir.

When the human papillomavirus (HPV) vaccine was first introduced to help prevent cervical cancer and anal warts and cancers, it was only recommended for 11- or 12-year old girls. However, the CDC later expanded their HPV vaccination recommendations to include 11- and 12-year old boys. By including males, the public health officials hoped to do all but one of the following:

decrease the basic reproductive number (R0) of HPV

Tuberculosis is the name of the ___________ caused by the _________ Mycobacterium tuberculosis.

disease; bacterium

Where are infectious diseases transmitted

either a host's portal of exit or a reservoir to a new host

If a disease occurs at a fairly stable rate, it is said to be

endemic.

Food-borne transmission

enter the body in food that is improperly prepared or contaminated with fecal material

Waterborne transmission

fecal material enters the water supply

Appropriate action to control infectious disease where humans are the reservoir would include __________.

immunization

When is a disease sporadic in a region

in only a few cases occur in that region

A patient acquires an infection by touching a contaminated door handle. Which mode of transmission best describes this scenario?

indirect contact transmission

The typical progression of symptoms for an acute infection would be __________.

infection-incubation-acute period-decline period-convalescence

Human immunodeficiency virus (HIV) __________.

infects and replicates in macrophages and T-helper cells

Toxic shock syndrome __________.

is life-threatening because of the superantigen toxin produced

Borrelia burgdorferi is an interesting spirochete that is unusual when compared to other bacteria. Which of the following is the reason that it is so unusual?

it has a linear chromosome

The incidence of disease in a population is termed the __________.

morbidity

Expected prevalence of a disease is

the expected occurrence of a disease based on past observations.

A patient exhibiting arthritis secondary to Lyme disease is likely in which phase of the infection?

third

Examples of direct contact

touching, kissing, sex, mother to fetus, or self contact (nose to eye)

Plague is transmitted through the bite of an infected flea. Which of the following best describes this mode of transmission?

vector transmission

A dog develops a diarrheal disease after drinking water from a creek during a hike with his owner. Which of the following best describes this method of disease transmission?

vehicle transmission

Epidemiology is defined as the study of

where and when a disease occurs, and how it is transmitted.

Which of the following would be considered a vector?

A fly carrying disease from fecal matter to food

Which of the choices shows the correct progression of bubonic plague?

2. Rodent is infected with Yersinia pestis. 4. Flea is infected with Yersinia pestis. 6. Yersina pestis reproduces in intestine of infected organism. 1. Human is bitten by infected flea. 3. Yersinia travels to lymph nodes. 5. Septicemia occurs.

The respiratory tract has multiple systems to help protect against airborne diseases. Which of the following summarizes some of these systems?

A mucociliary blanket to remove contaminants, secretion of lysozyme and other antimicrobial chemicals, and alveolar macrophages helps protect against airborne diseases.

Which of the following would be considered a fomite?

A toy

Which of the following is considered a major category of transmission of disease?

Contact, vehicle, and vector transmission

Which of the following is the correct progression of a herpes simplex 2 infection?

Direct contact with infected tissue occurs; lesions develop; virus goes dormant in nerve cells; virus is reactivated to cause lesions.

Pandemic

Epidemic on more than one continent at the same time

Clostridium tetani is an obligate anaerobe that can cause tetanus. When it enters the human body, it can produce tetanus toxin. Considering that C. tetani is an obligate anaerobe, which of the following explains how it can survive and cause disease in the human body?

Especially in deep wounds, C. tetani can sometimes survive in areas with damaged tissue and poor to no blood flow.

Most people experience several colds each year. Why is it that people do NOT develop immunity to the viruses that cause the common cold?

Even when only the colds caused by rhinoviruses are considered, there is enough variation in the antigens presented by these viruses that they are often not recognized by the immune system even in an individual who has only recently recovered from a cold.

Autoimmune diseases sometimes develop shortly after an infection. This is the case with rheumatic fever. Which of the following is the most likely reason that there is often a relationship between autoimmune disorders and infection?

Some pathogens, like the rheumatogenic strains of S. pyogenes, contain antigens that resemble normal cell surface proteins. As the immune system responds to them, it attacks the cells with similar antigens as well.

Which of the following matches are correct regarding streptococcal infections?

Streptococcus pyogenes: scarlet fever

What can you deduce from the treatment strategy for M. tuberculosis infection?

The organism has some innate resistance to antibiotics.

Which is an example of vehicle disease transmission?

The presence of Listeria on undercooked chicken served for dinner

If a human is bitten by an animal that has rabies, then it is recommended that the human receive immune globin (human rabies antibodies) and a rabies vaccination (with inactive virus) as well. Which of the following is the best (and most specific) explanation for why both are recommended in this case?

The rabies antibodies provide a rapid response but short-lived response while the vaccination provides slower but longer-lasting protection.

Which of the following describes an example of antigenic shift?

The surface antigens of a virus become drastically changed as a result of the combining of genetic material from different viruses without one organism.

Based on the concept map, which of the following must happen during Lyme disease?

There is an adaptive immune response.

What is the role of epidemiology?

To learn how to treat and prevent various diseases.

Vehicles

air, water, food, bodily fluids that are handled outside the body

The distribution of disease can change very quickly. An increase in emerging diseases can be attributed to __________.

an increase in international travel

Tuberculosis continues to be an infectious disease of worldwide concern on account of __________.

an increase in multi-drug-resistant strains

Influenza vaccines do NOT provide lifelong immunity on account of __________.

antigenic drift in the neuraminidase and hemagglutinin proteins

Lyme disease and syphilis are similar in that they __________.

are both caused by spirochetes and are chronic infections that involve the nervous systems

Vectors

arthropods that transmit diseases from on host to another insects, arachnids

A person who tests positive for the human immunodeficiency virus but shows no symptoms of AIDS would be termed a __________.

carrier

Waterborne disease type

cholera

When aerosols containing pathogens spread disease from a distance of less than one meter, it is considered

contact transmission.

In the first reported epidemiological study in 1854, John Snow attempted to discover the source of a London cholera epidemic by going house-to-house and recording deaths. When he mapped the results, he was able to identify the Broad Street water pump as the likely source of contaminated water. The data collected in this study was__________.

mortality

Example of Vector/disease

mosquito/malaria flea/ bubonic plague

Example of droplet transmission

mucus droplets within a distance of less than on meter Exhaling, speaking, coughing, sneezing

The tetanus exotoxin, produced by Clostridium tetani, __________.

prevents inhibitory signals that allow for muscle relaxation

What is contact transmission

spread of pathogens by direct contact, indirect contact or droplets

Airborne transmission

spread of pathogens via an aerosol dust, droplets, further than one meter

Indirect contact examples

spreading of pathogens by inanimate objects called fomites needles, eating utensils, money, tissues, toys, medical equipment