Final Exam Flashcards
(209 cards)
1
Q
What are the main antigen categories?
A
proteins and polypeptides: enzymes, cell surface structures, and exotoxins
lipoproteins: cell membranes
glycoproteins: blood cell markers
nucleoproteins: DNA complexed into proteins, but not pure DNA
polysaccharides: (certain bacterial capsules) and lipopolysaccharides
2
Q
alloantigens
A
cell surface markers and molecules that occur in some members of the same species, but not others
3
Q
what are alloantigens the basis of
A
basis for an individual’s blood group and MHS profile
responsible for incompatibilities that can occur in blood transfusion or organ grafting
4
Q
superantigens
A
bacterial toxins that are potent stimuli for T cells
activate T cells at a rate of 100 times greater than ordinary antigens
result can be overwhelming release of cytokines and cell death
5
Q
allergens
A
antigens that evoke allergic reactions
6
Q
antigen-presenting cells
A
dendritic cells, macrophages, B cells
7
Q
T-cell-indepedent antigens
A
antigens that can trigger B cells directly without APCS, or T helper cells
8
Q
virally infected cells
A
recognize virus peptides displayed on the cell surface
9
Q
intracellular bacterial infections
A
Tc cells can destroy
10
Q
cancer cells
A
Tc constantly survey the tissues and immediately attack any abnormal cells they encounter
11
Q
gamma-delta T cells
A
have T-cell receptors rearranged to recognize a wide range of antigens
frequently respond to certain kinds of PAMPs in the same way as nonspecific WBCs
respond more quickly and produce memory cells
12
Q
natural killer (Nk) cells
A
lack specificity for antigens
circulate through the spleen, blood, and lungs
probably first killer cells to attack cancer cells and virus-infected cells
destroy these cells in a similar fashion as T cells
not part of specific immunity, but sensitive to interferon
13
Q
natural killer T (nkt) cells
A
hybrid cells that are part killer cell and part T cell
have T-cell receptors for antigen and ability to release large amounts of cytokines very quickly, leading to cell death
another bridge between nonspecific and specific immunity
14
Q
hypervariable region
A
the site of the antibody where the epitope begins
amino acid content is extremely varied
15
Q
opionization
A
attachment of antibody to foreign cells and viruses is followed by binding of the Fc end to phagocytes
16
Q
isotopes
A
structural and functional classes of immunoglobins
17
Q
what are the two forms of IgA
A
dimer and monomer
monomer that circulates in small amounts in the blood
dimer that is a significant component of mucous and secrous secretions of the salivary glands, intestine, nasal membranes, breast, lung, and genitourinary
18
Q
colostrum
A
earliest secretion of breast milk; high in IgA that coats the gastrointestinal tract of a nursing infant
19
Q
natural immunity
A
any immunity that is acquired through the normal biological experiences of an individual
20
Q
artificial immunity
A
protection from infection obtained through medical procedures such as vaccines and immune serum
21
Q
how does active immunity occur
A
occurs when an individual receives immune stimulus that activates B and T cells to produce immune substances such as antibodies
22
Q
what are the three characteristics of active immunity
A
creater memory that renders the person ready for quick action upon re-exposure to the same antigen
requires several days to develop
lasts for a relatively long time
23
Q
how does passive immunity occur
A
occurs when an individual receives antibodies from another human or animal
recipient is protected for a short period fo time even though they have not had prior exposure
24
Q
what is passive immunity characterized by
A
lack of memory for the original antigen
lack of production of new antibodies against the disease
immediate onset of production
short-term effectiveness as antibodies have a time limit
25
what was the first immunization attempt like?
consisted of drying and grinding up smallpox scabs & blowing them with a straw into the nostrils of vulnerable family members
26
variolation in the 10th century
deliberate innoculation of dried pus from smallpox pustules of one patient into the arm of a healthy person
used in parts of the Far East until it was brought to England
27
Edward Jenner
inspired by dairymaid who had been injected by cowbox and who was immune to smallpox
tested theory by injecting a young boy with material from human cow pox lesions, exposed him to small pox two months later, and the boy proved immune to the disease
28
what was Jenner's discovery
a less pathogenic agent could confer protection against a more pathogenic one
29
vaccination
any immunity obtained by inoculation with selected antigens
30
natural passive immunization
a developing fetus encounters selected antibodies that cross the placental barrier (IgA)
nursing newborn baby receives IgA antibodies from mother's breast milk
31
artificial passive immunization
involved the transfusion of horse serum containing antitoxins to prevent tetanus and treat diphtheria
32
gamma globulin
immunoglobin extracted from the pooled blood of many human donors
processing concentrates antibodies to increase potency and eliminate potential pathogens
33
artificial active immunity vaccinations
stimulate a primary response and memory response
prime the immune system for future exposure to a virulent pathogen\
if pathogen enters body, response will be immediate, powerful, and sustained
34
principles of vaccine preparation
protects against exposure to natural, wild forms of pathogen
have a low level of adverse side effects or toxicity; not cause harm
stimulate both antibody(B-cell) and cell-mediated(T-cell) response
long-term lasting effects
does not require numerous doses or boosters
35
whole cell or virus vaccines
live, attenuated cells or viruses
killed cells or inactivated viruses
36
conjugated vaccines
subunits conjugated with proteins to make them more immunogenic
37
dna vaccines
microbial DNA is inserted into a plasmid vector and inoculated into a recipient
human cells will take up some of the plasmids and expell the microbial DNA in forms of proteins
these foreign proteins will be recognized during immune surveillance and cause B and T cells to be sensitized
38
mRNA viruses
new with covid-19 Pfizer and Moderna vaccines
39
MRNA covid vaccines
MRNA translated to form proteins
MRNA is fragile would be destroyed(chopped up) by our natural enzymes if it were injected directly into the body
40
entering cells
adenovirus binds to receptors on cell surface and enter the cell
DNA for the gene that codes for the spike protein is injected into the cell nucleus
41
route of administration of vaccines
most vaccines: subcutaenous, intramuscular, intradermal
nasal and oral vaccines: available for only a few diseases, stimulates IgA production on mucuous membrane, easier to give than injections
42
adjurants
special binding substance required by some vaccines which enhances immunogenicity, prolongs antigen retention at injection site, etc
43
vaccine complications
vaccines must go through experimental tests but some complications occur:
local reactions at infection site
fever
allergies
other adverse outcomes
more serious reactions are extremely rare
44
acquired immunodeficiency syndrome
viral disease that attacks the immune system(lymphatic system disease)
first reported cases were in U.S. in 1981
45
what is the causative agent of AIDS
human immunodeficiency virus(HIV)
46
how many people have been infected with AIDS
at least 80 million people have been infected since early 1980s worldwide with HIV
47
what is the mode of transmission for HIV infection and AIDS transmission
direct contact
sexual contact(semen, vaginal fluids) with infected individuals
exposure to blood infected with HIV(needle sharing, blood transfusion, mother to infant in utero, open wounds)
48
what is HIV susceptible to?
does not survive outside host for long
susceptible to heat and disinfectants
49
what race is more likely to get HIV
African American men 7x more likely
50
human immunodeficiency virus overview
retrovirus in the genus Lentivirus
many retroviruses have the potential to cause cancer
produce dire, often fatal, diseases and are capable of altering the host's DNA
51
what two types are HIV divided into
HIV-1 is the more virulent type(99% of AIDS worldwide)
HIV-2 is less virulent and causes milder, AIDS-like disease and replicates predominately in macrophages, dendritic cells, and T cells
52
HIV infection and Aids causative agent
contain reverse transcriptase (RT), a "retrovirus"
catalyzes the replication of double-stranded DNA from a single-stranded RNA
can permanently integrate viral genes into the host genome that is then passed on to progeny cells
53
enveloped RNA virus
outermost layer is a lipid envelope
membrane glycoprotein spikes mediate viral adsorption to the host cell
can only infect host cells that display a combination receptor consisting of the CD4 marker plus the coreceptor CXCR-4
54
HIV pathogenesis
infects Th cells(CD4 or T4), macrophages, dendritic cells, monocytes, and B lymphocytes
HIV also interacts with coreceptors CCR-5 on target cells
enters a mucuous membrane or the skin and travels t dendritic cells that reside beneath the epithelium
55
where does HIV virus mainly reside?
96% of HIV virus in lymph nodes, 4% in the blood
56
how does the host lose the battle?
HIV infection does not always immediately kill the host cell
results in symptoms in host: fever, fatigue, weight loss, diarrhea, body aches
2 billion immune cells destroyed daily by HIV
over time, years, immune system cannot keep up
57
what are symptoms of HIV directly tied to
level of virus in the blood
level of T cells in the blood
58
what does diagnosis with AIDS require
(1) testing positive for the virus and
(2) meeting one of the following criteria:
CD4 cells below zoocells/microliter of blood
CD4 cells account for fewer than 14% of lymphocytes
experience one or more AIDS-defining illnesses
59
what are the initial symptoms of HIV and AIDS
fatigue, diarrhea, weight loss, and neurological changes
opportunistic infections or neoplasms(cancer)
60
what are some of the most virulent complications of HIV/AIDS
lesions occur in the brain, meninges, spinal column, and peripheral nerves
patients with nervous system involvement show some degree of withdrawal, persistent memory loss, spasticity, sensory loss and progressive AIDS dementia
61
how to prevent aids
avoid sexual contact with someone with AIds
avoid contaminated blood and breastmilk from infected people
barrier protection (e.g condoms) if HIV status unknown
preexposure prophylaxis
62
HIV treatment
no cure for AIDS
treatment directed at reducing viral load and disease symptoms
63
what are the four classes of drugs that delay the symptoms of AIDS
fusion inhibitors(FIs) prevent entry of HIV into cells by binding to gp41 protein
types of reverse transcriptase inhibitors
protease inhibitors inhibits viral maturation
integrate inhibitors
64
lymphatic system disease
can be caused by a number of bacteria or viruses
vast majority are caused by Epstein-Bcarr virus(EBV), a member of the human herpesvirus
initially infects B cells, later T cells
65
infectious mononucleosis transmission
direct oral contact and contamination with saliva are the principle modes of transmission
infected individuals will shed virus for up to 6 weeks until infection becomes latent
66
how does the latent infection of mononucleosis work?
latent infection will last rest of individuals life, making them a reservoir for the virus
67
infectious mononucleosis signs and symptoms
sore throat, high fever, swollen cervical lymphnodes, gray-white exudate in the throat, skin rash, enlarged spleen and liver
sudden leukocytosis
68
how long is the incubation period for mononucleosis
30 to 50 day incubation period
69
what is a strong hallmark of mononucleosis
fatigue
70
prevention and treatment of mononucleosis
rapid diagnostic tests
usual treatments are directed at symptomatic relief of fever and sore throat
antibiotics for secondary infections
no vaccines, no antivirals
hospitalization is rarely needed
71
what are some cancers typically associated with epstein barr virus
burkitt's lymphoma
lymphoma
cancer of B lymphocytes
nasopharyngeal carcinoma
72
influenza basics
respiratory system disease caused by influenza virus
influenza A, B, C viruses in the family Orthomyxoviridae
73
Subtype A influenza
most common, pandemics
most important human pathogen
74
Subtype B influenza
"flu" symptoms
usually found primarily in humans
milder form of the illness; no epidemics/pandemics
75
Subtype C influenza
just a mild respiratory disease
no epidemics/pandemics
76
what are the most common types of invasive disease caused by Haemophilus influenzae
pneumonia(lung infection)
bloodstream infection
meningitis
epiglottitis(swelling in throat)
cellulitis(skin infection)
infectious arthritis(inflammation of the joint)
77
negative-sense, ssRNA virus
known for extreme variability
undergoes constant genetic changes that alter the structure of its envelope glycoproteins
78
envelope
matrix protein
lipid bilayer
external glycoproteins
ion channels
79
hemagglutinin
any of a group of naturally occuring glycoproteins that cause red blood cells(erythrocytes) to agglutinate, or clump together(used in assays to identify viruses)
80
neuraminidase
breaks down protective mucosa coating of respiratory tracts
assists with viral budding and release
keeps viruses from sticking together
81
antigenic drift
minor change in influenza virus antigens due to gene mutation(point mutations) in a strain within a geographic area
82
antigenic shift
major change in influenza virus antigen due to gene reassortment
2 different strains of flu viruses(from human to animals) infect the same cell
83
pandemic (H1N1) 2009 Influenza
6 months pandemic
started in Mexico
caused by major change in the influenza genome
84
prevention of influenza
immunization(annual inactivated virus vaccine)
universal mRNA vaccine(could provide protection for all 20 strains)
85
clinical manifestations of influenza
invades mucous membranes of upper respiratory tract
chills, fever, headache, malaise, and general muscular aches and pains
86
treatment of influenza
antiviral drugs e.g. Tamiflu, Zofluza, Relenza keeps virus from multiplying and reduces flu symptoms
most effective when administered early because they limit the spread of the virus from cell to cell
87
why should aspirin be avoided in the treatment of the flu
may lead to Reye's syndrome, rare condition swelling of liver and brain
88
common cold basics
most common of infectious diseases
viral infections transmitted via airborne droplets(sneezing/coughing, fomites)
short in duration
symptoms are milder than those of other respiratory diseases
89
symptoms of common cold
rhinitis(inflammation of nose)
nasal obstruction
watery nasal discharge
malaise
usually no fever
90
coronavirus basics
single positive-strand RNA viruses
4 subtypes alpha, beta, gamma, delta
most cause mild infections:common cold symptoms
91
which subtypes of coronavirus are transmitted to humans
only alphacoronavirus(bats natural host) and betacoronavirus(bats and rodents are natural host)
92
zoonoses
transfer of disease-causing microorganisms from animals to people
transfer can occur back and forth between animals and bhumans
93
Severe Acute Respiratory Syndrome coronavirus, SARS-CoV
emerged in Guandong province of China in 2002 ultimately infecting 8,098 people and causing death
not transmissible until host develops symptoms
fever check greatly slowed spread
no SARS infections found since 2004
94
Middle-East respiratory syndrome coronavirus(MERS-CoV)
low human-to-human transmission
95
SARS-CoV-2
identified in December 2019
likely originated from bats as the reservoir, with small mammals as intermediate hosts
96
how was SARS-CoV-2 first recognized
first recognized as causing a deadly pneumonia
disease it causes is called Covid-19 from coronavirus disease 2019
97
covid-19 virus characteristics
S proteins protrude from viral surface resembling a crown
belongs to genus B-coronavirus
enveloped virus single-stranded positive-sense RNA genome
98
what are the four main structural proteins of covid-19
spike(s) glycoproteins
envelope(E) glycoproteins
membrane(M) glycoproteins
nucleocapsid(N) proteins
99
Alpha (B.1.1.7)
variant was first detected in the united states in December 2020,
100
Beta(B.1.351)
first detected in the united states at the end of January 2021
101
gamma(p.1)
variant was first detected in united states in January 2021
102
Delta(B.1.617.2)
variant was first detected in united states in march 2021
103
omicron(B.1.529, BA.1, BA1.1, BA.2, BA.3, BA.4, and BA,5)
first detected in South Africa in november 2021
104
covid-19 signs and symptoms
may present no symptoms at all or may lead to death quickly
first recognized for its pneumonia manifestations, it can damage blood vessels all over the body, leading to damage to the heart, kidneys, brain, and other organs
105
virus transmission of covid-19
human to human(droplet) and in rare cases animal to human(direct contact)
small particles emitted from infected persons nose or mouth through coughing, sneezing, singing, or talking
close contact with eachother
106
entry into the host covid-19
nasal and oral passages of respiratory tract
conjunctiva of eyes passing through nasolacrimal duct
oral cavity and esophagus
107
ACE2
lowers blood pressure, controls fluid balance, and regulates inflammatory response
108
covid-19 disease manifestations
stage 1:asymptomatic stage
-incubation time 4 to 5 days
stage 2: upper airway and conducting airway response
-clinical manifestations appear 2 to 14 days post exposure
stage 3: hypoxia
109
organs affected by covid-19
eyes, nose, lungs, liver, kidneys, cardiovascular system, brain, intestines
110
causative agent of tuberculosis
mycobacterium tuberculosis
111
mycobacterium
contain peptidoglycan, but bulk of cell wall is composed of unique lipids
112
mycolic acid
very-long-chain fatty acid
found in cell walls of acid-fast bacteria
contributes to pathogenecity of the bacteria
makes bacteria highly resistant to certain chemicals and dyes
113
mycobacterium infections
environmental microbes in soil, water, and house dust
cause a number of human infections that are difficult to treat
114
tuberculosis signs and symptoms
humans easily infected but quite resistant to disease development
85% confirmed in lungs, even though disseminated TB bacteria can result in tuberculosis in any organ of body
115
what are the three clinical tuberculosis forms
primary tuberculosis, secondary tuberculosis, disseminated/extrapulmonary tuberculosis
116
primary tuberculosis
can be asymptomatic or mild fever
infectious dose of 10 bacterial cells
patients can recover
form granulomas
117
secondary tuberculosis
live bacteria can remain dormant, then reactivate
chronic tuberculosis
severe symptoms develop including: violent coughing with greenish or bloody sputum, low-grade fever, anorexia, weight loss, extreme fatigue, chest pain
118
extrapulmonary tuberculosis
infection outside of the lungs: regional lymph nodes, kidneys(renal tuberculosis), long bones, genital tract, brain and meninges(tubercular meninges)
119
tuberculosis course of disease
tubercles form: composed of bacteria, macrophages, T cells, and human proteins
subsequent changes in tubercle may occur
120
tuberculosis transmission and epidemiology
transmitted via droplets of respiratory mucus suspended in air
can survive for 8 months in fine aerosol particles
also transmitted from infected animals and their products
disease develops slowly
121
susceptibility for tuberculosis influenced by
inadequate nutrition, debilitation of immune system, poor access to medical care, lung damage, genetics
122
treatment of latent tuberculosis
rifampin and rifapentine: 4 and 3 months, respectively
isoniazid:9 months
123
treatment of active tuberculosis
rifampin, isoniazid, ethambutol, and pyrazinamide:2 months
rifampin and isoniazid: either 4 or 7 months, depending on the case
124
what happens if an individual doesn't follow medication regimen for tuberculosis
results in MDR-TB
125
multidrug-resistant tuberculosis(MDR-TB)
being resistant to at least isoniazid and rifampin
requires treatment of 18 to 24 months with four to six drugs
126
extensively drug-resistant tuberculosis(XDR-TB)
MDR-TB strains with resistance to two additional drugs
127
causative agent of lyme disease
borrelia burgdorferi
128
signs and symptoms of lyme disease
slow-acting, but often evolves into a slowly progressive syndrome that mimics neuromuscular and rheumatoid arthritis
lesion, called erythema migrans(rash at site of tick bite looks like bull's eye)
129
initial(localized) stage of lyme disease
lesions, develops 1 week to 10 days after infection
expanding, ring-shaped, skin lesion
flu-like symptoms(fever, headache, stiff neck, and dizziness)
130
second(disseminated) stage of lyme disease
cardiac and neurological symptoms, such as facial palsy can develop
neurological abnormalities, heart inflammation, and arthritis
131
third(late) stage of lyme disease
several weeks or months later
crippling arthritis
severe chronic neurological complications and become severely disabled
132
borrelia burgdorferi
gram-negative bacterium
large spirochetes ranging from 0.2 to 0.5 mm in width and 10 to 20 mm in length
contain 3 to 10 irregularly spaced and loose coils
133
transmission and epidemiology of lyme disease
transmitted primarly by hard ticks
passes through a complex 2-year tick cycle that involves two principal hosts
ixodes scapularis: black-legged deer tick found in the Northeast
134
lyme disease prevention and treatment
tick control and avoiding ticks: anyone outdoors should wear protective clothing, boots, leggings, and insect repellant containing DEET
exposed individuals should: check bodies regularly for ticks, remove ticks without crushing
135
treatment of lyme disease
early, prolonged(2 week) treatment with doxycylcine and amoxicillin is effective
other antibiotics such as cefriaxone and penicillin are used in late lyme disease therapy
136
fungal diseases basics
many fungi are normal part of microbiome
about 300 fungal species known to cause human disease
137
what are the three types of human fungal diseases?
community-acquired infections:caused by environmental pathogens in the general population
hospital-associated infections:caused by fungal pathogens in clinical settings
opportunistic infections: caused by low-virulence species infecting people with weakened immune responses
138
dermatophytes
group of fungi that cause a variety of body surface conditions
confined to the nonliving epidermial tissues(stratum corneum) and their derivating(hair and nails)
all conditions have names beginning with tinea, derived from erroneous belief that they were caused by worms
139
ringworm causative agents
trichophyton, microsporum, and epidermophyton
causative agent varies by geographic location and is not restricted to one genus or species
140
pathogenesis and virulence factors of ringworm
dermatophytes have ability to digest keratin(fibrous protein forming the main structural constituent of hair, feathers, hoofs, claws, horns, etc
fungi do not invade deeper epidermal layers
141
transmission and epidemiology of ringworm
direct contact and indirect contact with other humans or infected animals, soil, fomites
142
what is therapy for ringworm
topical, antifungal ointment applied for several weeks:
several drugs work by speeding up loss of outer skin layer
143
superficial mycoses signs and symptoms
involve the outer epidermal surface
innocuous infections with cosmetic rather than disease-causing effects
144
causative agent of superficial mycoses
tinea versicolor, a condition that is caused by the yeast Malassezia, a genus that has at least 10 species living on the skin
also implicated in folliculitis, psoriasis, and seborrheic dermatitis(dandruff)
145
meninges
three membranes that envelop the brain and spinal cord(dura mater, arachnoid, pia mater)
no normal microbiota in the CNS or PNS
when infection is suspected, a spinal tap is made, gram-stained and cultured
presence of microbes indicates deviation from healthy state, generally includes inflammation
146
meningitis cryptococcus neoformans signs and symptoms
causes a chronic form of meningitis with a gradual onset of symptoms, onset may be fast in AIDS patients and disease is more acute
coughing, fever, nausea, and neck stiffness
147
causative agent of meningitis cryptococcus neoformans
fungus with a spherical or ovoid shape
small, constricted buds
large capsule
148
transmission and epidermiology of meningitis
primary ecological niche is the bird population
masses of dried yeast cells are scattered in dust and air
enter respiratory tract, lungs, later can spread to skin, bones, viscera, and the CNS
149
where are the highest rates of infection occurring for meningitis cryptococcus neoformans
in patients with AIDS, typically fatal
150
meningitis coccidioides species causative agent
fungi that causes "valley fever"
151
coccidoides pathogenesis and virulence factors
true systemic infection of high virulence
begins as pulmonary infection, but can disseminate throughout the body
in meninges is most serious manifestation
all persons inhaling arthrospores probably develop some degree of infection, but some have genetic susceptibility
152
coccidioides transmission and epidemiology
highest incidence in southwestern U.S
outbreaks are usually associated with farming activity, archeological digs, construction, and mining
climate change, which is drying out much of the southwestern and western U.S.
153
coccidioides prevention and treatment
usually go away within a few months without treatment
healthcare providers sometimes provide antifungal medication in severe instances
154
treatment medication of coccidioides
3 to 6 months of flucanozole
155
histioplasma capsulatum
all continents
highest incidence in Eastern and central U.S.(east of rocky mountains)
grows most abundant in moist soils high in nitrogen content
156
histioplasmosis signs and symptoms
most poeple exposed to fungus hisoplasma never have symptoms, other people may have symptoms that go away on their own
157
symptoms of histioplasmosis
fever, cough, fatigue(extreme tiredness), chills, headache, chest pain, body aches
symptoms may appear between 3 and 17 days after breathing in fungal spores
158
transmission and epidemiology of histioplasmosis
breath in spores, enter lungs, transform into yeast form, can travel to lymph noes and spread to other parts
159
treatment of histioplasmosis
prescription antifungal medication is needed to treat severe histoplasmosis in lungs
course of treatment can range from 3 months to 1 year
160
community-acquired pneumonia:pneumocystitis jiroveci
one of the most frequent opportunistic infections in AIDS patients and cancer patients
likely transmitted through inhalation of spores
may be part of normal microbiota in healthy people
161
candida auris why is it concerning
often multidrug-resistant, meaning resistant to multiple drugs commonly used to treat candida infections
difficult to identify with standard lab methods and can be misidentified
caused outbreaks in healthcare settings
162
parasitic amoeboid protozoa
predators of bacteria
frequent parasites of animals
163
entamoeba histolytica
one of the most significant pathogenic amoebas
infection occurs by human ingestion of a mature cyst that has 4 nuclei
excystment occurs in lower region of small intestine
trophozoites enter the large intestine
164
parasitic infection of entamoeba histolytica
1 passed in feces
2 infection occurs by ingestion of mature cysts in contaminated food, water, or hands
3 excystation occurs in small intestine and trophozoites are released
165
intestinal amoebiasis signs and symptoms
initial targets are cecum, appendix, colon, and rectum
large intestine secretes enzymes that dissolves tissues, actively penetrating deeper layers of mucosa and leaving ulcerations
phase is marked by dysentery, abdominal pain, fever, diarrhea, and weight loss
166
dysentery
infection of intestines resulting in severe diarrhea with the presence of blood and mucus in feces
167
life-threatening manifestations of intestinal amoebiasis
hemorrhage, perforation, appendicitis, and tumor-like growths called amoebomas
168
extraintestinal amoebiasis signs and symptoms
occurs when amoebas invade the viscera(deep layer) of peritoneal cavity
space within the abdomen containing intestines, stomach and liver
pulmonary amoebiasis is more rare
169
entamoeba transmission and epidemiology
harbored by chronic carriers whose intestines favor the encystment stage of the life cycle
chronic diarrhea, cyst formation cannot occur in active dysentery, cysts are spread in feces
infection acquired by ingesting food or drink contaminated with cysts
170
prevention and treatment of entamoeba
relies on purification of water
no vaccine
regular chlorination of water supplies does not kill cysts
more rigorous methods such as boiling or iodine are required
t
171
medications for entamoeba
metronidazole or chloroquine
dehydroemetine used to control symptoms but will not cure disease
oral or IV therapy used to replace electrolytes and fluid
172
meningocephalitis
disease of both meninges and brain
caused by two amoebas: neagleria fowleri
acanthamoeba
173
how does meningocephalitis occur
accidental parasites that invade the body only under unusual circumstances
results of swimming, burrows in nasal mucosa, multiplies and migrate to brain
174
PAM
primary amoebic meningocephalitis
causes massive destruction of brain and spinal tissue that results in hemorrhage and coma
175
acathamoeba
granulomatous amoebic meningocephalitis (GAM)
direct contact: invades broken skin, the conjuctiva, and occasionally lungs
176
giardia lamblia
most common flagellate isolated in clinical specimens
177
signs and symptoms of giardia
diarrhea of long-duration, abdominal pain, and flatulance
stools have a greasy, foul-smelling quality to them
fever is usually not present
178
giardia and G. intestinalis trophozoite
forms cysts and trophozoites
trophozoites attach to intestinal epithelium and interfere with nutrient absorption
179
giardia transmission and epidemiology
by cyst-contaminated water
most common form of epidemic waterborne diarrheal diseases
cysts play a greater role in transmission, usually ingested with food and water
180
infectious dose of giardia
10 to 100 cysts
181
prevention and treatment of giardia
vaccine against giardia for animals but not humans
avoid drinking from freshwater sources
treatment with antiprotozoal drugs
182
malaria causative agent
plasmodium species are protozoans in the sporozoan group
development of the malarial parasite is divided into two distinct phases
-asexual phase and sexual phase
183
asexual phase
carried out in the human
184
sexual phase
carried out in the mosquito
185
malaria first symptoms
malaise, fatigue, vague aches, and nausea with or without diarrhea, followed by chills, fever, and sweating
186
falcriparum malaria
persistent fever, cough, and weakness for weeks without relief
187
complications of malaria
hemolytic anemia from lysed red blood cells
organ enlargment and rupture due to cellular debris that accumulates in the spleen, liver, and kidneys
188
cerebral malaria
one of the most serious complications of falciparum malaria
small blood vessels in brain become obstructed due to red blood cells
decrease in oxygen in the brain can cause coma and death
189
malaria prevention
long-term mosquito abatement and human chemoprophylaxis
sterile male mosquitos
humans reduce risk by: using netting, screens and repellents, remaining indoors at night, taking weekly doses of antimalarial drugs
190
malaria treatment
quinine has been a mainstay of malaria treatment
chloroquine, used in nonresistant forms of the disease
malarial protozoan has developed resistance to nearly every drug used for its treatment
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toxoplasmosis
protozoan parasite that infects most species of warm-blooded animals, including humans, and causes the disease toxoplasmosis
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toxoplasma gondii signs and symptoms
most cases are asymptomatic or marked by mild symptoms such as sore throat, lymph node enlargement, and low-grade fever
patients with immune suppression due to infection, cancer, or drugs have a grim outlook
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pathogenesis of toxoplasma gondii
obligate intracellular parasite with ability to invade host cells
parasite undergoes a sexual phase in intestine of cats and is released in feces
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sources of infection for toxoplasma gondii
foodborne transmission: raw or undercooked meat, drinking unpasteurized goat's milk
animal to human transmission:unhygienic handling of cat feces
mother to child
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cryptosporidium symptoms
mimic other types of gastroenteritis: headache, fever, fatigue, sweating, vomiting, severe abdominal cramps, and severe diarrhea
AIDS patients may experience chronic persistent diarrhea
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how does cryptosporidium mainly outbreak
half of outbreaks of diarrhea associated with swimming pools are caused by cryptosporidium
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cryptosporidum treatment
treatment usually not required for otherwise healthy patients
antidiarrheal drugs may be used to treat symptoms
no curative antimicrobial agent
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cyclospora
fecal-oral transmission, most cases associated with consumption of fresh produce and water contaminated with feces
disease outbreaks associated with raspberries, salad, and drinking water
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helminths
include tapeworms, flukes, and roundworms
adult specimens are usually large enough to be seen with naked eye
not all flatworms and roundworms are parasites
200
where do parasitic helminths typically spend part of their lives
in the gastrointestinal tract
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flatworms
very thin, often segmented body plan
divided into cestodes(tapeworms) and trematodes(flukes)
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roundworms
nematodes
elongated, cylindrical, unsegmented body
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general worm morphology
multicellular animals that are equipped with organs and organ systems
in pathogenic helminths, the most developed organ is the reproductive tract
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nematodes(roundworms)
sexes are separate and different in appearance
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trematodes(flatworms)
sexes can be separate or hermaphroditic
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cestodes(flatworms)
generally hermaphroditic
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routes of infection of helminths
oral intake or penetration of tissues
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egg laying of helminths
fertilized eggs released to the environment
provided with a protective shell and extra food to aid their development into larvae
vulnerable to heat, cold, drying, and predators
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enterobius vermicularis
pinworm or seatworm
common infestation of large intestine
