BIO205 Lecture Exam 4

compromised host

an individual whose resistance to infection is impaired two principal conditions: broken skin or mucous membranes and a suppressed immune system

vector transmission

animals that carry pathogens from one host to another most important=arthropods ex) mosquitos can be mechanical or biological

antitoxin

antibodies against a spcific toxin

biological transmission

arthropod vector active process such as insect bites, pathogen reproduces in vector ex) protozoan and helminthic parasites

mechanical transmission

arthropod vectors passive transport of the pathogen on the insect's feet or other body parts

contagious diseases

diseases that are very communicable and capable of spreading easily and rapidly from one person to another ex) chickenpox, measles

opportunistic pathogens

don't cause disease in normal habitat in a healthy person but may do so in a different environment ex) E coli

Describe where and how pathogens are contracted sexually? Diseases?

genitourinary tract may penetrate unbroken membrane or broken ex) HIV, genital warts, chlamydia

What is the ID50

how much it takes for 50% of the population to get a pathogen the infectious dose for 50% of the test population

hyaluronidase

hydrolyzes hyaluronic acid, which holds together certain cells of the body thought to be involved in the tissue blackening of infected wounds to help the microorganism spread

epidemic disease

if many people in a given area acquire a certain disease in a relatively short period

toxoids

inactivated exotoxins used in vaccines

capsules ___ the virulence of pathogenic species how?

increases impairs phagocytosis

the invasion or colonization of the body by pathogenic microorganisms

infection

healthcare associated infections (nosocomial)

infections that patients acquire within healthcare settings that result from treatment for other conditions. 5-15% of all hospital patients acquire nosocomial infections

incubation period

interval between initial infection and first signs and symptoms

reservoir of infection

living or nonliving continuous source of infectious disease

predisposing factor

makes the body more susceptible to a disease and may alter the course of the disease

describe adherence

means of a pathogen attaching to host tissues at the portal of entry

microbial communities that live in and on the human body

microbiomes

systemic (generalized infection)

microorganisms or their products are spread throughout the body by the blood or lymph

describe the MMWR

morbidity and mortality weekly report provides information on morbidity (incidence) and mortality (deaths)

exotoxin

mostly seen in G+ bacteria protein, water soluble/heat liable so heat can kill it produced inside some bacteria as part of their growth and metabolism and are secreted by the bacterium into the surrounding medium or released following lysis destroy particular parts of the host's cells or inhibiting certain functions among the most lethal substances known rare

what are the portals of entry for pathogens

mucous membranes, skin, and direct deposition beneath the skin or membranes (parenteral route)

microbial antagonism/competitive exclusion

normal microbiota can benefit the host by preventing the overgrowth of harmful microorganisms competition among microbes

microorganisms that establish permanent residence but do not produce disease under normal conditions

normal microbiota/normal flora

noncommunicable disease

not spread from one host to another caused by microorganisms that normally inhabit the body and only occasionally produce disease ex) tetanus

prevalence

number of people in a population who develop a disease at a specified time, regardless of when it first appeared

incidence

number of people in a population who develop a disease during a particular time period

airborne transmission

occurs through contact with contaminated respiratory droplets spread by a cough or sneeze

local infection

one in which the invading microorganisms are limited to a relatively small area of the body

commensalism

one of the organisms benefits and the other is unaffected ex) staph epidermidis, eyelash mites

parasitism

one organism benefits by deriving nutrients at the expense of the other ex) disease causing bacteria

acute disease

one that develops rapidly but lasts only a short time

secondary infection

opportunistic infection after a primary (predisposing) infection ex) pneumonia as a consequence of AIDS

the manner in which a disease dvelops

pathogenesis

pathogenicity vs virulence

pathogenicity is the ability to cause disease by overcoming host defenses and virulence is the degree of pathogenicity

scientific study of disease

pathology

carrier

people who harbor pathogens and transmit them without exhibiting any signs of illness

describe the parenteral route

portal of entry via punctures, injections, bites, cuts, wounds ex) teatnus, gangrene

bacteremia

presence of bacteria in the blood

toxemia

presence of toxins in the blood

viremia

presence of viruses in the blood

siderophores

proteins secreted by pathogens that bind iron more tightly than host cells using the host's nutrients

prodromal period

relatively short period that follows the period of incubation in some diseases mild symptoms

what is the easiest and most frequently traveled portal of entry for infectious microorganisms? diseases?

respiratory tract ex) cold, pneumonia, TB, influenza

examples of mucous membrane portals of entry

respiratory, GI, genitourinary tract

period of decline/recovery

signs and symptoms subside vulnerable to secondary infections

contact transmission

spread of a disease agent by direct, indirect contact or droplet transmission direct requires close association between infected and susceptible host indirect spread by fomites (inanimate objects), glass, toothbrush, clothing droplet (airborne droplets)

fecal oral transmission

spread of disease via eating, drinking, or licking food, water, or objects contaminated by feces both waterborne and foodborne transmission

indirect contact transmission

spreads to a host by a nonliving object called a fomite ex) stethoscopes, tissues, drinking cups

mutualism

symbiosis that benefits both organisms ex) E coli in intestine synthesizes vitamins for us and it benefits by getting nutrition from the large intestine

focal infection

systemic infection that began as a local infection

direct contact transmission

the direct transmission of an agent by physical contact between its source and a susceptible host ex) kissing, touching, sexual intercourse

period of convalescence

the person regains strength and the body returns to its prediseased state BUT may be a reservoir

epidemiology

the study of the distribution of mental or physical disorders in a population

sepsis

toxic inflammatory condition arising from the spread of microbes, especially bacteria or their toxins, from a focus of infection

cross contamination

transfer of pathogens from one source (often food) to another

microorganisms present for several days, wekks, or months and then disappear

transient microbes

vehicle transmission

transmission by an inanimate reservoir (food, water, air) ex) tapeworm, fungal spores

congenital transmission

transmission of diseases from mother to fetus or newborn at birth

droplet transmission

transmission via airborne droplets less than 1 meter ex) sneezing

Give examples of exotoxins (types and diseases)

types: cardiotoxins, hepatotoxins (liver), leukotoxins, enterotoxins diseases: botulism, tetanus, traveler's diarrhea, anthrax, toxic shock syndrome, staph aureus

period of illness

when the disease is most severe overt signs

What are the four ways a microorganism can damage host cells?

1. By using the host's nutrients 2. By causing direct damage in the immediate vicinity of the invasion 3. By producing toxins, transported by blood and lymph, that damage sites far removed from the original site of invasion 4. By inducing hypersensitivity reactions

describe 3 zoonoses

1. Rabies-bite 2. Cat-scratch disease-direct contact 3. Lyme disease-tick bites

Koch's Postulates (4)

1. The same pathogen must be present in every case of the disease. 2. The pathogen must be isolated from the diseased host and grown in pure culture. 3. The pathogen from the pure culture must cause the disease when it is inoculated into a healthy, susceptible laboratory animal. 4. The pathogen must be isolated from the inoculated animal and must be shown to be the original organism.

HAIs result from the interaction of what factors

1. microorganisms in the hospital environment 2. the compromised status of the host 3. chain of transmission in the hospital

coagulase

A bacterial enzyme that causes blood plasma to clot helps pathogens penetrate by walling off from the host

host

An organism on which a parasite lives.

describe the CDC

Center for Disease Control employs universal precautions to control healthcare associated infections publishes MMWR

emerging infectious diseases

Diseases that are new, increasing in incidence, or showing a potential to increase in the near future

zoonoses

Diseases transmitted from animals to humans

What is LD50?

Estimation of the lethal dose in 50% of a population; the dose at which 50% of the population will die from the toxin

how do microorganisms gain access to teh GI tract? Diseases?

Food and water via contaminated fingers mostly destroyed by stomach acid, but those that survive can cause disease ex)hep A, typhoid fever, amebic dysentary, cholera

What do the pathogenic properties of viruses depend on?

Gaining acces to a host, evading the host's defenses, and causing damage to or death of the host cell while reproducing themselves

endotoxins

Gram- made of lipopolysaccharides which means it has lipid A which is responsible for fever Heat stable (cannot be killed with heat) released only when bacteria die and their cell walls break down stimulate macrophages to release cytokines in very high concentrations activates blood clotting proteins, fever septic shock, miscarriage do not promote effective antitoxins

What does preferred portal of entry indicate? Examples?

Preferred portal of entry is a prerequisite to being able to cause disease ex) Typhoid fever only occurs if the microorganism is swallowed. Rubbing it against the skind oes nothing

waterborne transmission

Spread of pathogenic microorganisms via water. ex) sewage

descriptive epidemiology

The aspect of epidemiology concerned with organizing and summarizing health-related data according to time, place, and person

foodborne transmission

The contamination of food with an organism that can cause disease.

toxins

Various poisonous substances produced by some microorganisms (bacteria and viruses). primary factor in contributing to pathogenic properties

endemic disease

a disease constantly present in a population

communicable disease

a disease in which an infected person transmits an infectious agent, either directly or indirectly, to another person who in turn becomes infected ex) chickenpox, influenza, genital herpes

subacute disease

a disease that is intermediate between acute and chronic

chronic disease

a disease with a more or less slow onset and long duration

sporadic disease

a particular disease occurs only occasionally

symbiosis

a relationship between two organisms in which at least one organism is dependent on the other

primary infection

acute infection that causes the initial illness

the attachment between pathogen and host is accomplished by means of surface molecules on the pathogen called ___ or ___ that bind specifically to complementary surface receptors on the cells of certain host tissues

adhesins/ligands

subclinical infection

aka inapparent infection doesn't cause any noticeable illness

pandemic disease

an epidemic disease that occurs worldwide

true or false. unbroken skin is easily penetrated by microorganisms

false-unbroken skin is unpenetrable

septicemia

blood poisoning, a systemic infection arising from the MULTIPLICATION of pathogens in the blood

when infection results in any change from a state of health abnormal state in which part or all of the body is incapable of performing its normal functions

disease

toxigenicity

capacity of microorganisms to produce toxins

antigenic variation

changes in surface antigens that occur in a microbial population makes it unaffected by body's antibodies

kinase

enzymes that break down fibrin and thus digest clots formed by the body to isolate the infection

cause of disease

etiology

What is the purpose of biofilms

evade phagocytosis