Microbiology - Chapter 13

Signs and Symptoms of Inflammation

*Earliest symptoms of disease as a result of the activation of the body defenses -Fever, pain, soreness, swelling *Signs of inflammation -Edema- accumulation of fluid -Granulomas and abscesses- walled-off collections of inflammatory cells and microbes -Lymphadenitis- swollen lymph nodes

Signs of Infection in the blood

- Leukocytosis-increase in white blood cell count - Leukopenia-decrease in the level of white blood cells - Septicemia-microbes are multiplying in the blood and are present in large numbers - Bacteremia-small numbers of bacteria are present in the blood, but not multiplying - viremia-presence of viruses in the blood, whether or not they are actively multiplying

Identify why some diseases are "notifiable," and provide four examples of such reportable diseases.

- The disease has significant public health significance (TB, Anthrax) - Where disease has significant economic impact on the agricultural industry (FMD, CSF, CBPP) - Where disease has impact on trade (Contagious agalactiae) EX. Rabies, Bluetongue,Vesicular stomatitis, & lumpy skin disease

Discuss the three major types of epidemic, and identify the epidemic curves associated with each.

--Point-source epidemic-one in which the infectious agents came from a single source common-source epidemic-result from common exposure to a single source of infection taht can occur over a period of time -propagated epidemic - results from an infectious agent that is communicable from person to person and is sustained over time in a population -pandemic - spread of an epidemic world wide, ie - ebola (signs and symptoms it looked like flu)

Indirect Spread by Vehicles

-Fomite - an inanimate object that harbors and transmits pathogens (glasses, door knobs) -Oral-fecal route-Fecal carrier when inadequate personal hygiene contaminates food during handling (hepatits A, amoebic dysentery, shigellosis, typhoid fever)

Benefits of normal biota

-Influence the development of organs -Prevent the overgrowth of harmful microorganisms

List and describe three factors that weaken host defenses and increase susceptibility to infection.

-Old age and extreme youth (infancy, prematurity) -Genetic defects in immunity and acquired defects in immunity (AIDS) -Surgery and organ transplants -Organic disease: cancer, liver malfunction, diabetes -Chemotherapy/immunosuppresive drugs -Physical and mental stress -Other infections

6. Define bioterrorism, and list examples of possible biological agents.

-the use of a biological agent (bacteria, virus, toxin) to intentionally cause disease in civilian populations for the purpose of creating terror -an epidemic may be the end result some can be spread from person to person (smallpox virus) and some cannot (anthrax) certain agents do not cause harm to humans but disrupt the economy (foot and mouth disease virus-- contagious disease of cattle) -capable of causing widespread economic damage and public concern -has almost no capacity to infect humans caused outbreaks in the UK

Describe three ways microbes can cause tissue damage.

1) directly through the action of enzymes 2) directly through the action of toxins (both endotoxins and exotoxins) 3) indirectly by inducing the host's defenses to respond excessively or inappropriately.

8. List several virulence factors, and summarize their actions within a host.

1. Exoenzymes: break down and inflict damage on tissues, dissolve host's defense barriers and promote the spread of microbes into deeper tissues (secreted by pathogenic bacteria, fungi, protozoa, and worms) 2. Exotoxin: secreted by a living bacterial cell to the infected tissues Endotoxin: not actively secreted, only found in outer membrane of gram- negative bacteria

List Koch's postulates, and explain alternative methods for identifying an etiologic agent.

1. the suspected pathogenic organism should be present in all cases of the disease and absent form healthy animals 2.the pathogenic organism should be isolated from the infected animals and cultivated in pure culture 3.such a culture when inoculated into susceptible animals, should initiate characteristic disease symptoms 4.the pathogen should be re-isolated fmor the experimentally infected animals and shown to be the same as the original pathogen isolated in step 2

Areas of body without Normal Biota

All internal tissues and organs (heart, circulatory system, liver, kidneys, bladder, brain and spinal cord, muscles, fluids within an organ or tissue (blood, urine in kidneys, saliva prior to entering the oral cavity, amniotic fluid, etc)

zoonisis

An illness that can pass from an animal to a human. Human host is a dead end for the organism

Define opportunism, and list examples of common opportunistic pathogens.

An infectious microorganism that is normally a commensal or does not harm its host but can cause disease when the host's resistance is low. Can be caused by bacterial, viral, fungal, or protozoan pathogens Examples: • Candida albicans - a causal agent of opportunistic oral and genital infections in human. • Staphylococcus aureus - occur as commensal on human skin but may cause staph infections. • Pseudomonas aeruginosa - most common cause of burn and external ear infections, and is the most frequent colonizer of medical devices (e.g.catheters)

Pathogen

An organism that causes disease -an organism whose relationship with its host is parasitic

Animals as reservoirs

Animals are Vectors - they transmit the infectious agent from one organism to another (arthropods-insects.) Biological vector-insects that bite (mosquito, bats) Mechanical vectors-fly lands on burger(flys)

Infections that go unnoticed

Asymptomatic-host is infected but does not manifest the disease subclinical-patient experiences no symptoms or disease and does not see medical attention inapparent infections-most infections are attended by some sort of sign

Endogenous infections

Caused by biota already in the body. Can occur when normal biota is introduced to a site that was previously sterile. Example - Escherichia coli entering the bladder, resulting in a UTI

CDC

Center for Diseases Control Prevention (CDC)

Acute infections

Come on rapidly Have short-lived effects ie, influenza

Summarize the goals of epidemiology and the roles of the Centers for Disease Control and Prevention (CDC).

Epidemiology- effects of disease on the community. The CDC is responsible for keeping track of infectious diseases nationwide.

period of invasion

infectious agent multiplies at high levels and exhibits greatest virulence, height of infection (antibiotics can still be given if its a bacterial or fungal infection)

The minimum number of microbes required to cause diseases is the _______ ______.

infectious dose

During the period of ________, a pathogen exhibits its greatest virulence.

invasion

Sequelae

long-term or permanent damage to tissues or organs

incidence rate

measures the number of new cases over a certain time period. AKA morbidity rate

localized infection

microbes enter the body and remains confined to a specific tissue (boils, fungal skin infections, warts)

Define infectious dose, and explain its role in establishing infection.

minimum number of microbes required for an infection to spread • Microbes with a smaller infectious dose have greater virulence (severity of disease)

Microbial antagonism (competitive exclusion)

normal microbiota compete with pathogens or alter the environment -general antagonistic effect "good" microbes have against intruder microorganisms -microbes in a steady, established relationship are unlikely to be displaced by incoming microbes example - Escherichia coli entering the bladder, resulting in a UTI

secondary infection (opportunistic infections)

occurs when a primary infection is complicated by another infection caused by a different microbe

point source epidemic

one in which the infectious agents came from a single source

A _______ is an epidemic occurring over multiple continents.

pandemic

Covalescent stage

patient responds to infection and symptoms decline (still communicable)

horizontal transmission

person to person

The ________ rate is the number of persons afflicted with infectious disease.

prevalence

Chronic Infections

progress and persist over a long period of time

Convalescent carriers

recuperating without symptoms (Hepatitis A)

A ________ is objective evidence of disease.

sign

2. Enumerate the sites where normal biota/normal flora is found in humans.

skin and adjacent mucous membranes, upper respiratory tract, gastrointestinal tract including mouth, outer portion of urethra, external genitalia, vagina, external ear, external eye;

nonliving reservoirs of infection

soil, water, air

asymptomatic carrier

someone who is infected with a disease organism but is not experiencing symptoms (STIs)

Incubating carriers

spread the infectious agent during the incubation period (mononucleosis)

Symptoms

subjective evidence of disease as sensed b y the patient (chills, pain, fatigue, headache, nausea)

Aerosols

suspensions of fine dust or moisture particles in the air that contain live pathogens

incubation period

the time from initial contact with the infectious agent to the appearance of first symptoms

prevalence of disease

total number of existing cases with respect to the entire population

Compare and contrast major characteristics of exotoxins and endotoxin.

• Exotoxin: Secreted by a living bacterial cell to the infected tissues • Endotoxin: Not actively secreted, Cause fever and shock, Found shed from the outer membrane of gram-negative bacteria

Differentiate between a microbe's pathogenicity and its virulence.

• Pathogenicity: Describes an organism's potential to cause infection or disease • Virulence: The relative severity of the disease caused by a particular microorganism (determined by ability to establish/cause damage)

Differentiate among the various types of reservoirs, providing examples of each.

• Reservoir: a permanent place for an infectious agent to reside -Animals- zoonotic infections -Humans -Non-living; soil, air, water, fomites

List several portals of entry and exit.

• Respiratory tract • Salivary glands • Urogenital tract • Skin cells • Fecal matter • Blood

The number of new cases of disease over a certain time period is the ________.

incidence

Differentiate between the terms incidence and prevalence.

incidence - measures the number of new cases over a certain time period (morbidity rate (incidence rate) prevalence - total number of existing cases with respect to the entire population Prevalence of disease: - Total number of existing cases with respect to the entire population • Incidence of disease - Measures the number of new cases over a certain time period - Also known as case or morbidity rate • Mortality rate: - Measures the number of deaths in a population due to a certain disease

Chronic Carriers

individuals who shelter the infectious agent for a long period after recovery because of the latency of the infectious agent (TB, typhoid fever)

systemic infection

infection spreads to several sites and tissue fluids usually in the bloodstream. Infections can travel by means of nerves or cerebrospinal fluid. -viral - measles, rubella, chickenpox, aids -bacterial - brucellosis, anthrax, typhoid fever, syphilis -fungal: histoplasmosis, cryptococcosis

5. List examples of emerging and reemerging infectious diseases.

Influenza. Multidrug-resistant tuberculosis (MDR-TB) Nipah virus. Rabies. SARS coronavirus. Tick-borne encephalitis virus. Tick-borne hemorrhagic fever viruses. Crimean-Congo hemorrhagic fever virus.

Primary Infection

Initial infection. Someone came into contact with a true pathogen

mortablity rate

Measures the number of deaths in a population due to a certain disease

The Human ________ Project identifies areas of human body that have a normal microbiota

Microbiome

exogenous infection

Originating from outside the body, the environment, another person or animal.

1. Differentiate among the terms colonization, infection, and disease.

Pathologic state - cumulative effects of infection damage, disruption of tissues and organs, results in disease. Colonization - the establishment and multiplication of microbe on the body surface Infection - condition in which pathogenic microorganisms penetrate host defenses, enter the tissues, and multiply. Disease - any deviation from health Infectious disease - disruption of tissues or organs caused by microbes or their products

List the steps a microbe has to take to get to the point where it can cause disease

Step 1) Portal of entry (usually thorough skin or mucous membranes or gastrointestinal tract or respiratory tract or urogenital tract) Step 2) Attaching to the host (adhesion using fimbriae) Step 3) Survive host defenses (Antiphagocytic factors are virulence factor used by pathogens to avoid phagocytes) Step 4) Cause disease (Virulence factors: structures, products, or capabilities that allow a pathogen to cause infection in the host) Step5 - Portals of Exit (secretion, excretion, discharge, sloughed tissue)

Discuss how the Human Microbiome Project has changed our understanding of normal biota.

The HMP will collect genetic sequences in gut, respiratory tract, skin, etc. and tell us what microbes are there. Even microbes that can't be grown in a lab. Also, to figure out the role of normal biota in health and disease

True/False: The etiology of all infectious diseases can be determined by Koch's Postulates.

True

True/False: Your gut biota can determine your mood and mental health.

True

contagious disease

a type of highly communicable disease that spreads quickly from person to person

STI

account for 4% of infections worldwide, 13 million new cases in the US each year

Carrier

an individual who inconspicuously shelters a pathogen and spreads it to others; may or may not have experienced disease due to the microbe (asymptomatic)

virulence factors

any characteristic or structure of the microbe that contributes to toxic production or induction of an injurious host response. ie, capsule protects from phagocytes, coagulate - disguises bacteria from a blood clot, spike protein is a virulence factor

Disease

any deviation from health

Signs

any objective evidence of disease as noted by an observer (fever, chest sounds, swollen lymph nodes)

true pathogens

capable of causing disease in healthy persons with normal immune defenses (HIV)

opportunistic pathogens

cause disease when the host's defenses are compromised or when they grow in part of the body that is not natural to them (Pneumocystis jiroveci)

Mixed infections

caused by more than one microbe

infection

condition in which pathogenic microorganisms penetrate host defenses, enter the tissues, and multiply.

vertical transmission

from parent to child

infectious disease

disruption of tissues or organs caused by microbes or their products

droplet nuclei

dried microscopic residues created when microscopic pellets of mucus and saliva are ejected from the mouth and nose

polymicrobial diseases examples

gas gangrene, wound infections, dental caries, human bite infections

prodromal stage

earliest notable symptoms of infection appear, when you wake up with a tickle in your throat and you know something isn't right (stage when tamiflu is effective)

focal infection

Exists when the infectious agent breaks loose from a local infection and is carried to other tissues ie, tuberculosis, streptococcal pharyngitis -> strep throat -> scarlet fever, skin infection. Toxemia - infection remains localized, toxins are carried through the blood to the target tissue

True/False: Babies born by caesarian section are colonized by the same biota as babies born vaginally.

False

True/False: The lungs are sterile sites.

False

True/False: If a virus causing a respiratory disease is ingested, it will not cause disease.

False it depends on where it migrates. if the virus can survive Ph then it can survive in small intestine.

Define healthcare-associated infection, listing common types and their causative agents.

Healthcare-associated infection-Infectious diseases that are acquired or develop during a hospital stay or stay in another health care facility. UTI, Surgical site infections, Lower respiratory tract infection, gastroenteritis.

Purpose of Human Microbiome Project

Identify areas of human body that have a normal microbiota

Morbidity and Mortality Weekly Report

Reported cases of specified notifiable diseases are reported weekly in the Morbidity and Mortality Weekly Report. It lists morbidity and mortality data by state and region of the country. Prepared by the CDC. WHO - reports for the world

List six different modes of horizontal transmission, providing an infectious disease spread by each.

STI's, malaria, bubonic plague, Rickettsiae caused typhus, Chagas disease

Epidemiology

effects of diseases on the community involves the study of the frequency and distribution of disease and distribution of disease and other health-related factors in defined populations.

________ diseases are caused by newly identified microbes.

emerging (HIV, SARS, Novel strains of influenza)

Antiphagocytic factors

Virulence factor used by pathogens to avoid phagocytes Circumvent some part of the phagocytic process

A(n) _______ disease is seen at a steady frequency over a long period of time in a particular location.

endemic

Bacterial ________ are toxic to the host in high doses.

endotoxin

Bacterial ________ are toxic to the host in minute amounts.

exotoxins (cholera vibero - bad diarrhea)

Phagocytes

White blood cells that attack invading pathogens by means of enzymes and antimicrobial chemicals

syndrome

a collection of signs and symptoms that represent one specific disease (ie HIV)

noncommunicable disease

a disease that is not transmitted from one host to another

communicable disease

a disease that is spread from one host to another

latency stage

a dormant state of an infectious agent (Chickenpox to shingles, herpes)

reservoir

a permanent place for an infectious agent to reside