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What are the two types of pathogen and what is a pathogen?
- a pathogen is any disease causeing microorganism
primary and opportunistic pathogen
What is parasitism?
what does it often require?
what is it an example of?
often requires an extended relationship or coexistence betwen parasite and host.
an example of symbiosis.
What do paraasitic infections usually involve?
what are the two hosts involved?
definitive host is the final host which maintains the mature for m of the parasite and has the sexually reproductive form of the parasite
intermediate host is what maintains the immature parasite and its where it undergoes various stages of development before being transferred to the definitive host.
Based on the site of colonization, what are the two types of parasites?
ectoparasites are organisms that live on the surface of a host.
endoparasite are organism that lives on the inside of the host.
Based on the acquisition source, what are the two types of parasites?
exogenous are infections that reslut from enoucnters withpathogens in the environment.
endogenous are acquired infecitons that caused by pathogens or pothential pathogens in or on the body.
What are the wto types of intracellular pathogens?
based on the babiliy of the pathogen to invade and live within host cells
obligate intracellular pathogen
facultative intracellular pathogen
What is pathogenesis?
What is pathogenicity?
the process by which microbes cause disease in a host. steps involved in diesse progression wihtin the host.
theability of microbes to cause disease an the capacity of a pthogen to invade and harm a host.
What doespathogenicity depend on?
- physicall/structural factors
- (capsul, outer membrane)
- biochemical factors - proteins (toxins)
- Genetic factors- resistance genes
related to virulence
What are pathogenicity islands?
- large segments of dna that code for virulence factors; often acquired during horizontal transfer
- clusters of pathogenicity genes encoding virulence factors
What is inflamation?
What is inflamation characterized by?
a nonspecific defense mechanism
by the body in response to infection, injury or chemical irritation.
- rubor: redness from blood acculmulation
- calor: heat caused by the blood due to vasoconstriction
- tumor: swelling or edema from the accumulation of fluid in surrounding tissue
- dalor: pain soreness or tenderness from injury to local nerves
- sometimes itching (pruritus)
What are the five stages of inflamation?
- vascular hcanges
- increase in vascular permeability
- leukocyte migration
- chronic inflamation
- resulution and healing :
What are the signs of infection in the blood, morbidity?
- speticemia is whenn there is bloos poisoning and multiplying microbes in the bloos; prescence of toxins
What are viral pathogenic effects referred to as?
What are the trhree ways it occurs?
- viral overload
- cytocidal effect
- non-cytocidal effect
What is sequels?
permanent damage to tissues as a reslult of infection adn disease.
What is an idiopathic disease?
is when etiology, pathology and the prognosis is unkown.
What is epidemiology?
is the study of the frequency and distrivution (spread) of disease and other health-related problems within human populations.
What are the microbe categories that cause disease in humans?
- parasitic worms (helminths)
what are the two infection types based on pathogenesis?
what is toxinosis?
infection includes the signs and symptoms that result from the growth of miccrobes and their invasion into tissue.
are the signs and symptoms that are the result of the acion of toxins.
What are the three main categories based on the expression and duration of an infectious diesase?
- clinical are when the signs and symptoms are clearly evident and commonly referred to as a overt, apparent or symptomatic infection that included acute, fulminating, and chronic.
- sub-clinical is when the patient lacks symptoms and the infection is not yet detected by clinical examination or laboratory tests and are also called asumptomatic , inapparent, subvert, and covert infections.
- latent infections are when the microbe persists in a dormant state in host tissues for long periods of time and the pathogen cannot be found by culturing and the disease alternates between an acute and a subclinical state.
What are the three infection types that are based on location?
- local microbes are restricted to a limited region or anatomical area- abscess
- focal is when the infection spread from one localized are to otehr localized areas - tuberculosis
- systemic is also called disseminated or generalized and it is when microorganism circulates throughout the body and infects many different tissues-measles or typhoid.
what are the three infection categories that are based on the sequence of infection?
- primary infection
- secondary infection
What are the two categories of infection that are based on the types of species of organisms?
Polymicrobial infection is when the ismultaneous establishment of infection by several different microbes and also reffered to as a mixed infeciton
cross infection is the co-infection of a host by pathogens when they are transmitted between hosts.
What are nosocomial infecitons?
infectious diseases that are acquired and/or developed in hospitals.
What ar eopportunistic infections?
what are pyogenic infections?
what are pyrogenic infections?
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-febrile or pyretic microbes that induce fever.
What is meant by incubation?
what does the incubation length depend on?
time from the first exposure to the pathogen tothe thime symptoms become apparent.
depends on the health of the host, the virulence of the microbe, the generation time of the pathogen, thime for organism to migrate from point of entry to site of infeciton.
What is prodrome?
a short period before specific symptoms set in where the patient experiences malaise, general feeling of discomfort such as joint pain, headache, or muscle ache.
what happens at the decline stage in the stages of an acute infeciton?
the patient's condition worsens and the patient's immune system is working to contain and eliminate the microbe but has thus far been unsuccessful, elevated white blood cells, high levels of immunological molecules and antibodies, and the patient either recovers or the diseas is fatal.
What happens at the convalescence stage of an acute infeciton?
recovery period in wher the patient survives the infeciton and microbes and otoxins are eliminated from the body and signs and symptoms abate and patient starts to feel better and the affected tissues and systems are repaired.
What are the stages of acute infection?
What ar enon-infectious diseases?
diseases caused by factors other than microbes.
What are the non-infectious diseases caused by?
- congenital diseases- except teratogens and microbes causing
- degenerative diseases- except prions
- nutritional deficiencies- except parasitic worms
- endocrine diseases- except enteric microbiota
- mental diseases- except toxoplasma which causes herpes simplex virus
- immunological diseases- except sequela and hiv/aids
- neoplastic diseases-exept hpv cervical cance;ebv and burkitt's lymphoma
- iatrogenic disease-except nosocomial infections
- idopathic diseases
What are the eight characteristics of a successful pathogen?
- maintenance of the pathogen
- penetration of host
- persistense-evasion of host defenses
- invasion and toxigenicity
- dissemination and portals of exit
What are the three types of reservoirs?
What are the various zoonosis?
- sars which is the corona virus in bats and pigs.
- avian or bird flue such as the h5n3 influenza in birds
- plague which is caused by the yersinia pestis from rats
- cutaneous antracis which causes anthrax from cattle
What are the various human reservoirs?
- symptomatic carriers
- asymptomatic carriers such as incubatory carriers chronic carriers and latent/dormant carriers.
What are the various environmental reservoirs?
- house dust
What are the most common vectors tthat are arthorpods?
- mosquitoes.important in the spread of zoonotic diseases.
What are the two types of vectors?
Mechanical vectors that live on the external surfaces of the vector and the organism is not involved in the life cycle of the pathogen
Biological vectors are when the pathogen lives withing the body of the vector and often serves as the definitive host and also that the vector transmits the pahtogen by biting, sucking, and aerosol formation.
What are the types of mechanical vectors?
what are the types of biological vectors?
biting and blood sucking vecotrs such as flies (sand flies and tsests flies) mosquitoes, lice, tick, mites, and fleas.
What are the types of biting vectors?
Are they mechanical or biological vectors?
mosquitos inject saliva infected with the pathogen directly into the blood.
fleas penetrate the skin and dfecate around the wound and thereby introducing pathogen into the host
tsetse fly penetrate the skin and regurgitate infected blood into the wound.
What is parenteral transmission?
is when the pathogen is deposited directly into the blood stream, into tissue below the skin or into mucous membranes through injections, deep wounds, and insect bites.
What are some sites of entry in human hosts?
- mucosal surfaces:
- urogenital tract
- and conjuctiva (mucosal linding of the eye)
What is the alimentary tract portal of entry?
- mouth through ingestion of contaminated food and live in the stomach pH enzyme activity.
- salmonella, poliovirus, hep a viruse
3. portals of entry
What is the repiratory tract portal of entry?
- nose which is the pathogen that enters the body thorugh inhaled droplets or aerosols
- or through bacteria in such as (streptococcus) that causes sore trhouat, meningitis, diphthereia, and pneumonia
- viruses include the measles, mumps, chickenpox, and cold
how do virulence factors deal with colonization?
the establishment of a site of reproduction of the pathogen and an apporpriate portal of entry
the structures involved in colonizations are considered virulence factors becaseu adherance mechanisms and ways to overcome or withdstand the constant pressure of the host defeses at the surface are required.
What happens after colonization during invasion?
after colonization, many pathogens penetrate the host's mucous membranes and epithelial surfaces and the active mechanisms produce lytic enzymes that alter the host tissue while the passive mechanisms participate in pre-existing tissue damage and in existing internalization methods such as in endocytosis and phagocytosis.
5. evade host defenses'
Why have pathogens developed mechanisms to avoid host defenses?
- to hide from the immune system
- to avoid destruction by the immucne cells
- to persis and multiply within the host.
6. multiply within the host
What ar the various multipolication methods?
- binary fission (eukaryotes nad transverse or longitudinal fission)
- sexual reproduction
- bacteria nd protists
- the use of gametes
7. damage the host
What are the most potent toxins that act intracellularly?
- cytotoxins because the site of action is in the cytoplasm
- for diseases like diphtheria and botulism, the symptoms arealmost entirely casued by toxins rather than by the body's immune response.
what does cytophathic mean?
What does oncogenic mean
what does teratogenic mean?
- resulting in cell death
- cancer causeing
- damage to the fetus
8. find a new host
How are microbes transferred to a new host?
- repiratory and salivary: sneezing coughing and coughing and spitting
- skin which includes sweating
- fecal which includes defecation
- urogenital withch includes urinaition
- blood and bleeding
What are some effects caused by toxins?
What are bacterial toxins produced as and which toxin is the most potent?
when is the proenzyme activated?
- produced as proenzymes within the microbe; this form is incatve.
- botulinum toxin
once it leaves the cell (enzymatic cleavage or phosphorylation)
if the bacterial toxins are toxic to tother bacteria, what are they called?
How do antibiotics get their name?
What does it mean when toxins are antigenic?
listed by the body system they target in humans
when bacteriocins are used to kill other bacterial infections in the human body.
they stimulate the immune system
What are fungal toxins?
a grop called mycotoxins such as a flatoxin which ar eof the most napotent toxins
What causes shellfish poisoning in humans?
phycotoxins such as cyanobacteris (bacteria) and dinoflagellets (protozoa)
What are the two types of bacterial toxins based on viability of the bacterial cell?
based on location in relation to the vacterial cell?
based on action of toxin?
exotoxins are toxins secreted by live bactria
endotoxins are toxins released when the bacteria dies.
- exotoxins are toxins released into the surrounding area
- endotoxins are toxins that are critically associated with the bacteria.
- exo is when thte toxin work on intracellular targets of the host cell
- endo is whenthe toxin works at the surface of the host cell
Are exotoxins some of the most poisonous substances known to human?
can they have an effect far from where they are released?
During cellular metabolism, what form of the exotoxins are in?
Where does the exotoxin that is the most potent affect the cell based on action?
How are they the most potent?
- most of the exotoxins are potent becuase they are enzymes that catalyze the covalent modification of intracellular targets and have creative mechanisms for overcoming the barrier of the plasma membrane.
What are the categories of exotoxins that are based on the secretion method that bacteria use to export the protein out of the cell?
- 1. cytotoxins: type I-v
- 2. ab toxins
- 3. cytolytic toxins
- 4. superantigens
Why are cytotoxins called cytotoxins?
What are the advantages of cytotoxins?
- because the action of the toxin is within the cytoplasm
- the toxin is secreted directly into the cytosol in a contact-dependent manner
- cytotoxins are effictient in the sense that the poison enters only the target cell.
- cytotoxins are selective in the sense that intracellular target is specific.
what gram stain bacteria uses the mebrane damaging/pore forming cytotoxins?
where is the pore generated?
what do cytotoxins do to the host cell protein synthesis?
what happens to the ca?
plasma membrane of thehost cell
inhibit the synthesis of proteins
escapes from host cells
What gram stain bacteria use the cytotoxins that is injected directly into the cytoplasm of the host cell?
molecular syringes that resemble flagella (type 3)
molecular syringes that resemble conjugative pili (type iv)
What does the b domain/subunit do?
what does the a domain/subunit do?
- binds to cell surface receptors of host
- helps to translocate the a domain/subunit
- transferred across the plasma membrane into the host cell
- enters the cytoplasm and enzymatically acts on host tragets
What is a single ab protein
what is a single a subunit + many b subunits?
What is the tripartite toxins that has 2 a and on b subunits?
What do the binary toxins do?`
interact at the host membrane before entry