Question 1

Waterborne transmission of pathogens involving water contaminated by raw sewage is an example of what mode of transmission?

Accepted Answer

Waterborne transmission involving water contaminated by raw sewage is an example of indirect fecal-oral transmission, as the pathogens are transmitted through an intermediary (contaminated water) rather than directly from person to person.

Question 2

Pathogenic microorganisms that enter the body via contaminated food or water typically infect:

Accepted Answer

Pathogenic microorganisms that enter the body via contaminated food or water typically infect the digestive system. They can cause various infectious diseases such as gastroenteritis, food poisoning, and typhoid fever.

Question 3

Transmission of pathogens from person to person via sneezing,coughing or by the affected individual speaking near (less than 1 meter)a susceptible individual are examples of what mode of transmission?

Accepted Answer

The transmission of pathogens through bodily contact with an infected individual or their bodily fluids is known as contact transmission. This includes transmission through sneezing, coughing, or speaking near a susceptible individual, as mentioned in the question. Other examples of contact transmission include handshaking, hugging, and sexual contact. Vertical transmission occurs from mother to child during pregnancy, childbirth, or breastfeeding. Indirect contact transmission occurs through contact with contaminated objects or surfaces. Direct fecal-oral transmission occurs through ingesting fecal matter contaminated with pathogens. None of these modes of transmission fit the description given in the question.

Question 4

Which of the following pertain to foodborne transmission of infectious agents?

Accepted Answer

Foodborne transmission can occur through unsanitary food preparation practices such as poor hand hygiene, contaminated cutting boards or utensils, and cross-contamination between raw and cooked foods. Poorly treated drinking water can lead to waterborne transmission, while microorganisms in dry air may cause airborne transmission. Properly refrigerated foods can help prevent the growth of foodborne pathogens, but they do not pertain specifically to the transmission of infectious agents.

Question 5

Pathogenic microorganisms that are spread from person to person by unwashed hands contaminated by fecal matter,is an example of what mode of transmission?

Accepted Answer

Direct transmission refers to the spread of infection from one person to another through physical contact such as touching, biting, or kissing. The scenario described in the question, where pathogens are spread through unwashed hands contaminated with fecal matter, is an example of direct transmission.

Question 6

All of the following are associated with Yersinia pestis except:

Accepted Answer

Yersinia pestis, when acquired through the respiratory route, causes pneumonic plague, not bubonic plague. Bubonic plague is primarily transmitted through the bite of infected fleas.

Question 7

All of the following infectious diseases can occur in the fetus when the causative agents cross the placenta except:

Accepted Answer

Pneumonia is an infection of the lungs and does not typically enter the fetal bloodstream, so it does not cross the placenta. AIDS, syphilis, and rubella can all cross the placenta and cause infectious diseases in the fetus.

Question 8

Reservoirs of infections include:

Accepted Answer

Reservoirs of infections can be from humans, non-human vertebrate animals, as well as in water and soil. All three of these options can contain and spread various types of infections and illnesses.

Question 9

Pathogens that are delivered by insects follow what mode of disease transmission?

Accepted Answer

Pathogens that are delivered by insects follow vectorborne mode of disease transmission. In this mode, the insect acts as a vector and transmits the disease-causing pathogen from one host to another. Examples include malaria transmitted by mosquitoes and Lyme disease transmitted by ticks.

Question 10

Congenital diseases:

Accepted Answer

Congenital diseases are conditions present at birth and are often caused by infections that cross the placenta from an infected mother to the fetus. They are not caused by poorly cooked meat or contaminated water and do not just affect the mother.

Question 11

Fomites are:

Accepted Answer

Fomites are nonliving objects or surfaces that can become contaminated with infectious pathogens and can spread disease through indirect contact transmission.

Question 12

A zoonosis refers to an infectious disease that is transmitted:

Accepted Answer

A zoonosis refers to an infectious disease that is transmitted from a vertebrate animal to a human. Examples include Lyme disease transmitted from ticks to humans, or avian influenza transmitted from birds to humans. The other choices are not fully accurate definitions of zoonoses.

Question 13

A retrospective analytical study:

Accepted Answer

A retrospective analytical study does not enroll study participants before an epidemic occurs (A) nor compares participants that receive a drug with those that received an infection (C). It considers factors and data that occurred during an epidemic to determine which factors were causal, which is described in option D.

Question 14

Which of the following is not helpful in achieving control of disease transmission?

Accepted Answer

Propagation of vectors (such as mosquitoes or ticks) can actually increase the spread of disease, rather than control it. The other options listed (isolation, quarantine, and immunization) are all effective methods for achieving control of disease transmission.

Question 15

Which of the following are not examples of portals of exit?

Accepted Answer

The options A, B, and D are all examples of portals of exit for infectious agents. Urine and semen in males can contain infectious agents such as Chlamydia trachomatis, droplets from sneezing or coughing can contain infectious agents such as influenza virus, and breast milk can contain infectious agents such as HIV. However, pus in a liver abscess is not a portal of exit. It is a result of the immune system's response to an infectious agent and contains dead white blood cells and tissue debris.

Question 16

In herd immunity,typically 90% of the population is while 10 % is to an infectious disease.

Accepted Answer

In herd immunity, typically 90% of the population is immune, which helps to protect the remaining 10% who are susceptible to an infectious disease. This concept relies on a high proportion of individuals being immune, either through vaccination or previous infection, to reduce the spread of disease within a community.

Question 17

Sexually transmitted diseases are most often spread by what mode of transmission?

Accepted Answer

Sexually transmitted diseases are primarily spread through direct contact with an infected person's bodily fluids, such as blood, semen, vaginal secretions, and breast milk. Indirect contact, such as touching a contaminated object or surface, or mechanical vectors, such as insects, are not common modes of transmission for most STDs. While waterborne transmission is possible for some STDs, it is a much less common route of transmission compared to direct contact.

Question 18

Which of the following microorganisms is found in soil,a nonliving reservoir,and in animal fecal matter used as a fertilizer?

Accepted Answer

Clostridium tetani is found in soil, a nonliving reservoir, and can also be present in animal fecal matter used as fertilizer. This bacterium is known for producing the toxin that causes tetanus.

Question 19

A common portal of entry for microorganisms is/are:

Accepted Answer

Mucous membranes line various parts of the body such as the respiratory, digestive, and urogenital tracts, and provide a wet and moist environment that is suitable for microorganisms to enter and infect the body. It is a common portal of entry for several pathogens, including bacteria, viruses, fungi, and parasites.

Question 20

Which of the following organizations sets the standards for international disease control?

Accepted Answer

The World Health Organization (WHO) sets the standards for international disease control. The National Institutes of Health (NIH) is a research agency that focuses on biomedical and public health research within the United States. The Centers for Disease Control and Prevention (CDC) is a national public health agency in the United States that responds to domestic disease outbreaks and emergencies. The Public Health Service (PHS) is a division of the Department of Health and Human Services in the United States that oversees various public health agencies and programs.

Quiz 15: Epidemiology and Nosocomial Infections