Micro 3

• any disease causing microorganism
• 2 types: true/primary & opportunistic
• by nature are parasites

• can cause infection and disease in healthy people
• aka frank pathogen

can infect host only when immune defense is weakened

• any organism that lives on or in another organism and is either metabolically dependent upon that organisms or derives nutrients from that organism
• have complex microbial interaction where one organism benefits from the assoiciation and the other organism is usuaully harmed or killed

a larger organism that supports the survival and growth of a smaller organism

• requires an extended relationship or coexistence between parasite and host
• is an example of symbios (living together of organism)

• definitive host
• intermediate host

• maintains the mature form of the parasite
• maintains the sexually reproductive form of the parasite

• maintains the immature parasites
• immature parasite usually undergoes various stages of maturation before being transferred to the definitive host

• ability of microbes to cause disease
• the capacity of a pathogen to invade and harm a host

the steps involved in disease progression within the host

• degree or intensity of pathogenicity
• important indicator of disease progression after infection by a pathogen
• is determined by factors associated with the pathogen

• product of microbes that increases the invasiveness or pathogenicity of the organism
• contribute to tissue damage
• can be integral microbial cell components or secreted products
• can be secreted products
• can be genetic

• large segments of DNA that code for virulence factors
• often acquired during horizonatal transfer

the ability of microorganisms to establish an infection

number of pathogens that infect 50% of hosts within a specified period of time

ability of microorganisms to spread to adjacent tissues or other anatomical areas

• number of pathogens that kill 50% of the hosts within a specified period of time
• associated with toxin production

• deviation of the host from a healthy state to an unhealthy state
• abnormal state where part or all of the host is unable to perform the normal functions of the body
• termed a morbid state
• change is manifested by signs and symptoms

diseased state or condition

• objective evidence of disease
• characteristics of a disease that can be observed by someone else in addition to the patient

• subjective evidence of disease
• characteristics of disease that can only be determined by the patient

nonspecific defense mechanism by the body in response to infection, injury, or chemical irritation

• redness
• from blood accumulation

• heat
• warmth generated from the blood dur to vascoconstriction

• swelling (edema)
• from the accumulation of fluid in surrounding tissue

• pain
• soreness or tenderness from injury to local nerves

inflammation of the colon

inflammation of the meninges

inflammation of the kidney

swollen lymph nodes

organ or tissue undergoing inflammation

• small mass or nodule of inflamed tissue
• due to action of phagocytes and the subsequent accumulation of pus

collection of pus in a tissue, cavity or confined area surrounded by inflamed tissue

bacteria present in the blood but not multiplying

fungi present in the blood but multiplying

viruses present in the blood, but not necessarily multiplying

• multiplying microbes in the blood
• presence of toxins

• Combination of signs and symptoms that occur together and are indicative of a diseased or abnormal condition
• A complex of symptoms indicative of a morbid state

• Permanent damage to tissues as a result of infection and disease
• Plural:sequelae

• The study of diseased states
• The study of the structural and functional manifestations of disease
• A branch of medicine that examines the nature of disease, how the disease is manifested, and changes to the body that occur as a result of disease

• hypersensitivity reaction
• Associated with a second exposure or the chronic exposure to a pathogen
• Signs and symptoms are not associated with the direct action of the pathogen
• Instead, host has an exaggerated immune response to the presence of pathogen

• The process of determining the cause of the disease
• Commonly involves the use of chemical or immunological tests

• The projected outcome of a disease
• The prospect of recovery from a disease
• The recovery success (or a lack thereof) is based on the nature (pathology) of the disease

• Simply, prevention
• Measures used to prevent the spread and development of disease
• Is based on understanding the etiology and mode of transmission
• Includes vaccination, improving hygiene and sanitation, standards of living, education, etc.

• Relieving or soothing the symptoms of a disease or disorder without effecting a cure
• Providing relief from pain and other distressing symptoms

The study of the frequency and distribution (spread) of disease and other health-related problems within human populations

• The study of how diseases are causedFactors that cause disease include:Pathogens (infection) Genetics (genetic disorders)Immune dysfunction Biochemical/physiological deficiencies or changes, Psychological dysfunction
• Sometimes the etiology, pathology and prognosis is unknown (idiopathic disease)

ethiology, pathology, and prognosis is unknown

• disease caused by the presence and action of microorganisms
• deviation from a healthy state that is caused and maintained by microorganisms

• infection
• toxinosis (intoxication)

signs and symptoms result from the growth of microbes and their invasion into tissue.

signs and symptoms are the result of the action of toxins

• communicable
• noncommunicable

• Disease that is spread from one person to another
• Usually applies to human infections
• Associate the term “catch” with this form.

• disease that is not spread directly from one person to another
• Disease may be caused by the movement of normal flora, ingestion of pre-formed toxins, or exposure to microbes in the environment.

• zoonotic
• phytogenic

• disease that is spread from animals to humans
• disease cause by animal pathogens

• disease that is spread from plants to humans
• disease caused by plant pathogens

• overt
• subclinical
• latent

• signs and symptoms are clearly evident
• symptomatic
• Acute: Expression of disease is severe and short
• Fulminating: microbe is multiplying at a high level or with great intensity
• Chronic: Disease is persistent and lasts over long periods

expression of disease is severe and short

microbe is multiplying at a high level or with great intensity

disease is persistent and lasts over long periods

• The patient lacks symptoms
• not detected by clinical examination or laboratory tests
• Also called asymptomatic, inapparent, or covert

• The microbe persists in host tissues for long periods of time
• the disease alternates between an acute and a subclinical state.

• local
• focal
• systemic

Microbes restricted to a limited region or anatomical area

spread from one localized area to other localized areas

microorganism circulates throughout the body and infects many different tissues

• primary
• secondary

• host is colonized by a single pathogen type
• Initial infection often results in decreased immune surveillance and response; leaves patient immunocompromised

once host is infected, other pathogens will colonize the host

caused by the influenza virus, an orthomyxovirus

inflammation of the pharynx caused by Streptococcus pyogenes

• polymicrobial
• cross-infection

• the simultaneous establishment of infection by several different microbes
• Also referred to as a mixed infection
• Can include different taxonomic groups; e.g. bacteria and fungal spores in a puncture wound
• Can include the same taxonomic groups but different species

co-infection of a host where pathogens were transmitted between hosts infected with different organisms

• Infectious diseases that are acquired and/or develop in hospitals
• Usually refers to infections acquired by patients during hospitalization but can also be applied to infections acquired by medical personnel

Infection resulting from endogenous microbiota when the host immune’s system is compromised or if the microbe moves from its normal location to a new location in the body

Infection resulting in pus formation

• Infection resulting in fever; fever-inducing
• Pyrogen: microbe that induces fever

• Time from the first exposure to the pathogen to the time symptoms become apparent
• Length of incubation period varies considerably for some microorganisms
• Depends on the health of the host, the virulence of the microbe, the generation time of the pathogen, time for organism to migrate from point of entry to site of infection

• A short period before specific symptoms set in where the patient experiences malaise
• Malaise= a general feeling of discomfort

• Pathogen multiplying, producing toxins, etc.
• Signs and symptoms can include cough, rash, diarrhea, etc.
• Immune system is responding to pathogen
• Corresponds to symptoms seen during an acute or chronic infection

• The patient’s condition worsens
• The patient’s immune system is working to contain and eliminate the microbe but has thus far been unsuccessful
• There are high levels of immunological molecules, e.g. antibodies Elevated white blood cell count
• The patient either recovers or the disease is fatal
• Not evident in all infections

• Patient survives the infection
• Microbes and/or toxins are eliminated from the body
• Signs and symptoms abate and patient starts to feel better
• Affected tissues and systems are repaired

inherited, congenital, degenerative, nutritional, endocrine, mental, immunological, neoplastic, iatrogenic, idiopathic

cause of disease is unknown

caused by medical procedures or treatments, surgical errors, and or drug interactions

abnormal cell growth that leads to formation of tumors

disease of the immune system: allergies, autoimmune, aids

• can result from infection
• mostly due to emotional, psychological factors
• biochemical imbalance

due to excesses or deficiency in hormones

disease from lack of specific nutrient

disorders affecting one of more body systems that develop as patient ages

structural and functional defects present at birth

genetic disorders passed from parent to child

maintains a reservoir, leaves the reservoir and transported to the host, enters the host, establishes a site of reproduction and growth, evade the host defenses, multiply within the host, damage the host, leave the host and return to the reservoir or find a new host

• a place to live before and after infecting a host
• 3 types: animal, human, environmental

• wild and domestic
• zoonosis

• disease spread from animals to humans
• SARS:corona virus in bats and pigs
• avian flu:H5N3 influenza in wild and domestic birds
• plague:yersinia pestis in rats
• cutaneous anthrax: Bacillus anthracis in cattle

• symptomatic carriers
• asympotomatic carriers

those who are sick

• incubatory carriers: people who are infected with a pathogen but appear healthy; will get sick soon
• chronic carriers: people who are infected with a pathogen but do not become sick for months or years
• Latent/Dormant carriers: people who are infected with a pathogen that undergoes latency

• soil, water, food, air, insects, animals, house dust, fomites
• fomite: inanimate object that is used to spread diseases (door knob, toilet, tissue)

• exogenous
• endogenous

Exogenously acquired disease results from encounters with pathogens in the environment

Endogenously acquired disease are caused by agents in or on the body.

• The spread of a pathogen from one organism to another
• The transfer of disease from one organism to another
• Vertical: mother to child
• Lateral: person to person, environment to person, etc.
• If a disease is transmissible (capable of being spread from one organism to another) then the disease can be termed
• Infectious, contagious or communicable (are used interchangeably)

• the pathogen is deposited directly into the blood stream, into tissue below the skin or into mucous membranes
• needle injection, deep wounds, insect bites

• mucous surface (eye)
• skin-pathogen enters through break in skin
• ex. Clostidium tetani and tetanus. Herpes
• alimentary and respiratory tract
• genitourinary tract
• birth canal

• Mouth: enter via ingestion of contaminated food, drink, etc.
• Ingested pathogens can survive stomach pH and enzyme activity
• e.g., Salmonella, poliovirus, hepatitis A virus

• Nose: pathogen enters the body through inhaled droplets or aerosols
• inhaled particles can be deeply inhaledbacteria: sore throat (streptococci), meningitis, diphtheria, pneumonia
• viruses: measles, mumps, chickenpox, cold

• The establishment of a site of microbial reproduction on or within a host
• The presence of micoorganisms in a site of the body that may lead to tissue damage and signs of disease
• Structures involved in colonization are considered virulence factors
• requires attachment to surfaces on or in the host
• many pathogens penetrate the host's mucous membranes and epithelial surfaces