BIO212- Homework Module 7

Pathogenicity islands generally increase bacterial virulence and are absent in nonpathogenic members of the same genus or species. They range from ____________ kilobases and code for a variety of proteins that include pili and ____________ proteins.

10-200; secreted

Match the appropriate description of each component of the infectious disease chain to the correct box.

Agent- pathogenic bacteria ,virus ,fungi a-re the agents Exposure- pathogen must be transmitted from its reservoir to previous host Suspectibility -potential host vulnerability to the pathogen Virulence- and the degree to which an organism is pathogenic disease is called virulence. Dose -the lower the ID 50 or LD 50 the graetee the chance of infection.

Drag the labels to their corresponding mechanism of transmission.

Airborne transmission: coughing, sneezing, droplet nuclei, dust Contact transmission: kissing, sex, touching Vehicle transmission: surgical instruments, fomites, shared cups Vector-borne transmission: anthropods, animals, fleas, mosquitoes, ticks

Why do most microorganisms not cause disease upon entry of a human host?

All of the choices are correct.

To understand the nature of these epidemics and how they occur, one must understand how the effects of major genetic change to the pathogen, called ____________ , differs from the effects of minor genetic change to the pathogen, called ____________ .

Antigenic shift, antigenic drift

This microorganism is typically an extracellular pathogen.

Aspergillus

Survival of the pathogen also depends on its ability to avoid recognition by the ____________ cells. Some microorganisms survive and replicate inside host cells; in some cases, they reside in the ____________ that are supposed to destroy them. Other organisms squeeze between host cells, make ____________ to avoid phagocytosis, burrow under mucus, and secrete exopolysaccharides to form communal shelters within ____________ .

Defense, leukocytes, capsules, biofilms

A geographic information system (GIS) is a data management system that helps to chart infectious disease data. For what type of situation would this system be most effective?

Determining if a tick living at high elevation is associated with an outbreak of the vector-borne Lyme disease

Control of infectious disease falls into three categories. Classify the following types of disinfection, sanitation, and chemotherapy according to their associated control level.

Eliminate Source: - Disinfection UV irradiation of a hospital room Break Connections: - Sanitation pasteurization of milk and juices - Sanitation regular restaurant inspections - Chemotherapy antibiotics administered to end infectivity Decrease Susceptibility: - Chemotherapy prophylactic medicines when traveling

A disease is considered ____________ if it is constantly present at low levels within a population.

Endemic

Choose which of the following characteristics describe endotoxins versus exotoxins.

Endotoxins: - Lipopolysaccharide - Lipid A - Gram-negative infections - Produce fever - Heat stable - Weakly immunogenic - Cell wall material - Can cause septic shock - Usually on chromosomal genes Exotoxins: - Protein - No fever - Carried on plasmids - Excreted by living cells - Heat liable - Highly toxic - Antigenic

Some microorganisms produce ____________ that inactivate innate resistance mechanisms. Still other organisms have evolved specialized protein ____________ to selectively kill host cells.

Enzymes, secretion systems

Alternatively, if such increases occur only within a given population, this may indicate that there is an ____________ at hand.

Epidemic

Assess the following statements and classify them according to whether they refer to extracellular or intracellular pathogens.

Extracellular: - Multiply in the blood - Yersinia pestis Intracellular: - Chlamydia spp - All viruses - May be falculative or obligate

Which of the following statements is false regarding the efforts made by the U.S. government to prepare for a potential bioterrorism attack?

FBI screening of all laboratory workers who have access to potential agents of bioterrorism

Virulence is the potential for an organism to cause disease, whereas pathogenicity refers to the degree of harm caused by the organism.

False

While recovering in the hospital from heart-bypass surgery, Gerald was infected with rotavirus from his 3-year-old granddaughter when she came to visit him and used the bathroom in his hospital room. This is an example of a nosocomial infection.

False

Both Escherichia coli and Neisseria gonorrheae adhere to urethral epithelia using ________.

Fimbriae

Brian lives in a town where 98% of the population is immunized against measles. Brian is unlikely to get measles, despite the fact that he has never been immunized. This situation demonstrates the concept of _______.

Herd immunity

During 2007, there were 3.6 new cases of pertussis per 100,000 susceptible individuals in the United States, part of a steady increase that has been occurring since the 1980s. (https://www.cdc.gov/pertussis/clinical/index.html). This statistic illustrates the term ______.

Incidence

What has been the greatest change on public health over the past century as a result of public health surveillance?

Infectious diseases, previously the leading cause of death, diminished dramatically due to improvements in sanitation and antimicrobial drugs and vaccine implementation.

The number of organisms in the initial ____________ plays a role in disease development. A pathogen with a low ____________ is more virulent than one with a higher infectious dose. If a pathogen ____________ its host, then the LD₅₀ is quantified.

Inoculum; ID50; kills

Match the following terms related to disease processes with the appropriate description.

Invasiveness- The ability of the pathogen to spread to neighboring cells and adjacent tissues Pathogenecity islands- segments of the genome that codes for virulence factor Virulence - The magnitude of harm caused by organism Pathogenecity- The potential to cause disease

The value of GIS in tracking disease is that __________.

It manages the data from remote sensing and in creating maps, facilitates the analysis of relationships between the mapped data

Authorities have established an integrated system of laboratories so that a rapid and coordinated response to bioterrorism is in place. This conglomerate of laboratories is maintained by the ________.

Laboratory Response Network (LRN)

Control measures should be directed toward the part of the infectious disease cycle that is ________.

Most susceptible to control

Before bacteria can establish an infection, they must be able to overcome resident microbiota in direct competition for resources. Certain pathogens, often Gram- ____________ organisms, produce a ____________ secretion system that delivers lethal molecules from its cytoplasm to a competing organism through direct contact.

Negative; type VI

The ID50 refers to the _________.

Number of organisms in the initial inoculum required to cause infection in 50% of hosts

This type of pathogen cannot grow outside a host cell.

Obligate intracellular pathogen

Pathogens produce virulence factors primarily to ________.

Outcompete host cells for resources

Classify the statements that describe the mechanism of action of potential pathogens according to their strategy for avoidance of host defenses.

Overcoming: - Gram-negative pathogens produce type 6 secretion systems Evading: - Molecules are produced as decoys to confuse anticrobial proteins - Pathogens surface proteins are changed by recombination or mutation Supressing: - HIV infects immune cells and cripples the immune system over time

If sudden increases in disease occurrence occur worldwide, this may indicate the development of a ____________ .

Pandemic

Measles reached an all time low in the United States when the CDC declared it eliminated in 2000. In 2014, 667 cases were reported and cases continue to occur in clusters throughout the country. Which of the following provides the most plausible explanation for this reemergence?

Parents, worried that vaccines may cause harm to their child, decide not to vaccinate, effectively reducing the herd immunity for any given disease.

Large segments of bacterial chromosomal and ____________ DNA have been found to encode ____________ factors. These DNA segments are called pathogenicity islands, and they appear to have been inserted into the existing DNA of organisms as they evolved from ____________ cells into those that are capable of causing disease.

Plasmind; virulence; nonpathogenic

Microbes are often prioritized based on their threat to public health. Classify each disease listed based on its potential to be utilized as a biological weapon.

Potential bioterrorism agent: - Anthrax - Hanta Virus - Plague - Smallpox Not a likely bioterrorism agent: - Leprosy - Sleeping Sickness - Mumps - Malaria - Common Cold - Tuberculosis

Infectious disease outbreaks often follow certain patterns, with specific terms used to designate each pattern. Match the term with the recognized pattern of disease associated with that term.

Propagated epidemic- slow rise, followed by gradual decline in cases Pandemic- increase in disease around the world Common-source epidemic- peak level reached in short period of time, followed by rapid decline

If an epidemic arises from a communicable disease, then it is considered a ____________ epidemic where there is a ____________ rise in the number of cases.

Propagated; slow

There are three types of control measures used by scientists to prevent and control epidemics. Categorize each action into the appropriate type of control measure.

REDUCE OR ELIMINATE THE SOURCE OR RESERVOIR OF INFECTION- 1. Quarantine of carriers. 2. Wastewater treatment. 3. Use of antimicrobial drugs. BREAK CONNECTION BETWEEN SOURCE OF INFECTION AND THOSE SUSCEPTIBLE- 1. Pasteurization. 2. Insecticides. 3. Drinking water chlorination. 4. Mandatory hand washing by food handlers. REDUCE NUMBER OF SUSCEPTIBLE INDIVIDUALS AND RAISE HERD IMMUNITY- 1. Active immunization. 2. Passive immunization. 3. Prophylactic treatment.

When two adjacent thymine molecules are joined by a covalent bond as a result of exposure to UV light, this structure is referred to as a

Thymine dimer

Exposure comes via a specific mode of _____________ for that organism; either from its __________, or from a previously infected host. Transmission can be either direct or indirect.

Transmission; reservoir

The burgeoning human population, extensive global travel and past overuse of antibiotics all contribute to the development and spread of microorganisms.

True

There are many agencies that play a role in the tracking and control of disease. Match each agency with a specific characteristic or role that they play.

U.S. Public Health Service- Overseen by a central administrator, the Surgeon General Department of Health and Human Services- Oversees all health/education/welfare agencies created by Congress Centers for Disease Control and Prevention (CDC)- Develops and implements disease prevention and control in the United States World Health Organization- Provides global disease surveillance

How does this white card work to produce a control side of the plate?

UV light cannot penetrate a solid object so the covered side of the plate is not exposed.

Several parameters must be in place before an infectious disease can progress. The first is that a pathogenic agent (bacteria, fungus, or ____________ ) with sufficient ____________ is exposed to a host organism.

Virus; virulence

One strategy for exploiting host cells that is used by certain bacteria such as Listeria, Shigella, and Rickettsia is to ________.

use the actin filaments of the host cytoskeleton to facilitate motility through the host cell thereby enhancing infection of neighboring cells

Choose all of the following attributes that are necessary for any bacterial pathogen to attach to and colonize a host cell.

- Capsule production - Utilize spikes to attach to host cells - Presence of fimbriae

Check all of the parameters that are monitored by public health practitioners to identify population health issues.

- Genetic background - Environmental conditions - Behaviors/lifestyle choices - Emerging infectious agents - Antimicrobial resistance

Infectious diseases can either fall in the category of communicable or noncommunicable. Communicable diseases are represented by diseases such as ________.

- Gonorrhea, acquired through sexual contact with a partner infected with the bacterium Neisseria - Influenza, acquired by inhaling respiratory droplets laden with the influenza virus - Hepatitis A, acquired through the fecal-oral route from exposure to the hepatitis A virus

Infectious diseases can emerge or reemerge for a variety of reasons. What sort of data could reveal changes that are likely to lead to the emergence or reemergence of an infectious disease? (Check all that apply.)

- Increasing drug resistance to a commonly used antibiotic - Decrease in immunization use against the disease - Climate changes leading to an increased range of a vector

Healthcare-associated infections are of huge concern to healthcare personnel, causing 88,000 deaths annually. What measures would be recommended for prevention and control of healthcare-associated infections? (Check all that apply.)

- Routine hand washing - Wearing gloves when contacting bodily fluids like blood or saliva - Use of aseptic technique by hospital personnel

Which of the following organisms contain a pathogenicity island that encodes for Type III secretion proteins?

- Salmonella enterica - Shigella flexneri

Evaluate the statements below and choose those that are true regarding the exploitation of human cells by pathogens in order to survive.

- Viruses can fuse host cells into large syncytia so they can spread undetected - Pathogens can survive and replicate inside host's cells - Liver cells are made to produce decoy HBV proteins that "fool" antimicrobial proteins

Prevention and control information is particularly useful to determine the public health threat of a specific infectious agent. If one were to make a table of this information, what would the table contain? (Check all that apply.)

- Whether or not a vaccine is available - What type of chemotherapy is effective - How is the agent disseminated or transmitted - What diagnostic test is available

The U.S. government has invested national effort into creating a biological weapons defense. The initiatives include ______. (Check all that apply.)

- development of improved detection and diagnostic systems - preparation of clinical microbiologists and their laboratories as first-responder teams - a stockpile of specialized vaccines and medicines for civilian protection

Pseudomonas aeruginosa can form biofilms whereby the cells exhibit different characteristics to those of planktonic P. aeruginosa. Evaluate the statements below and choose those that correctly apply to biofilms.

-Cells in a biofilm can suppress the actions of phagocyctic leukocytes such as macrophages and neutrophils - Antibiotics, antibiodies, and hydrolytic enzymes are ineffective at killing cells in a biofilm - Pathogens are able to transfer plasmids, nutrients, and quorum-sensing molecules from cell to cell within a biofilm

Drag the definitions to their proper term in order to review common infectious disease terminology.

Bacteremia- Viable bacteria in the blood Endotoxin- Lipid A component of gram negative bacteria Exotoxin- Toxin released from a living bacterium ID50- Dose of pathogen needed to infect 50 % of exposed hosts LD50- Dose of pathogen needed to kill 50 % of exposed hosta Leukocidin- Microbial toxin that kills leukocytes Mycotoxin- Toxin produced by fungi Opportunistic pathogen- Normal microflora that can cause disease in immunocompromised hosts Pathogenicity island- Group of genes carrying virulence factors Septicemia- Growth of bacteria in blood Zoonosis- Human diseases aqcuired from animal hosts Pathogenecity- Ability to cause disease Virulence- The extent of a pathogen to spread to other tissues Latent stage- Period where no transmission occurs and no symptoms are present Viremia- Viruses present in the blood Invasiveness- Ability of a pathogen to spread to other tissues Superantigens- Toxins that overstimulate immune system

Healthcare-associated infections are commonly caused by ___________.

Bacteria of the microbiota

Which of the following DNA sequences would be the most likely to be damaged by UV radiation?

CTTGAATTAA

There are many things that people can do to help prevent the spread of infectious disease. Match each term with the action that it represents.

Chemotherapy- use of antibiotics for a bacterial infection Sanitation- routine treatment of drinking water Disinfection- periodic use of bleach on a kitchen countertop

Evaluate the statements below and choose those that would qualify as potential Tier 1 agents of a bioterrorism attack.

Clostridium botulinum - gram positive endospore forming rod producing deadly toxin Variola major- virus with a low infectious dose and population susceptibility Yersinia pestis -gram negative causing plague. Bacillus anthracis - gram positive endospore forming bacteria

Determine what type of A-B toxin (cytotoxin, neurotoxin, or enterotoxin) the following microbes produce.

Clostridium botulinum- neurotoxin Virbrio cholerae- enterotoxin Bordetella pertussis- cytotoxin

Drag the statements to the term they describe in order to review characteristics of virulence factors.

Coagulase: causes red blood cells to clot Collagenase: breaks down framework proteins in skin and connective tissue Elastase: degrades laminin in basement membranes Hemolysins: kill red blood cells Hyaluronidase: breaks down extracellular matrix holding tissues together Phospholipase: degrades components of the plasma membrane Leukocidins: kill white blood cells Pyrogenic toxin B: protease from group A streptococci Streptokinase: leads to degradation of fibrin clots

In contrast, if an epidemic arises from a noncommunicable disease, then it is considered a ____________ epidemic and there is a ____________ rise in the number of cases.

Common-source; rapid

Epidemiologists are interested in how infectious diseases spread within populations, especially those diseases that are ____________ , meaning spread easily from person to person.

Communicable

Most microorganisms do not usually cause disease when they enter a human host due to __________.

Competition between resident microbiota and the potential pathogen, as well as successful attack by innate and adaptive immune cells

UV light has ______ wavelengths than visible light waves, and its peak energy is at a wavelength of ______.

Shorter; 254nm

Which of the following would be appropriately sterilized using UV radiation?

Stainless steel surface in biological safety cabinet used for media preparation

Staphylococcus aureus has a pathogenicity island that codes for several ____________ , including the toxin that is active in toxic shock syndrome, while Shigella flexneri encodes a Type III ____________ that acts as a cytotoxin.

Superantigens; secretion system

A virulent primary pathogen can cause disease even when the host immune system is robust, and ____________ hosts can fall prey to their own microbiota if their immune system is compromised. In those cases, the organisms are considered ____________ pathogens.

Susceptible; opportunistic

The difference between the terms pathogenicity and virulence is __________.

That pathogenicity is the ability of an organism to cause disease to any extent, whereas virulence is the degree of harm inflicted on the host

In 1900, the leading single category of death in the United States was pneumonia/influenza, accounting for 11.8% of deaths. In 2010, pneumonia/influenza accounted for only 2.0% of deaths in the United States. This change is largely due to ______.

The impact of public health surveillance