Term
| what kind of virus is Polio? |
|
Definition
|
|
Term
| what kind of genetic material does polio have? |
|
Definition
| single stranded positive RNA |
|
|
Term
| what shape is poliovirus's coat and what/how many proteins does it contain? |
|
Definition
| Icosahedral- 4 proteins (VP1-4) |
|
|
Term
| what are the clinical manifestations of polio and how prevalent are they? |
|
Definition
-asymptomatic 90%
-fever/sore throat 5%
-meningitis 1%
-paralysis/encephalitis 0.1% |
|
|
Term
| what is the most common agent in severe viral diarrhea? |
|
Definition
|
|
Term
| what are the enteroviruses? |
|
Definition
-polio
-coxackie A/B
-echovirus
-enterovirus |
|
|
Term
| which enteroviruses do most children under five aquire? |
|
Definition
-rotavirus
-enteric enterovirus
-astrovirus
-calicivirus |
|
|
Term
| what kind of genetic material do rotaviruses have? |
|
Definition
| 11 segments of double stranded RNA |
|
|
Term
-What kind of capsule do rotaviruses have?
-do they have an envelope?
-what special enzyme do they carry? why? |
|
Definition
-triple layer icosahedral capsule
-no envelope
-RNA dependent RNA polymerase
-because our enzymes cannot make mRNA from a double stranded template |
|
|
Term
-where does rotavirus replicate?
-where does it get the outer layer of its capsule?
-how does it get out of the cell? |
|
Definition
-replicates in the cytoplasm
-breaks off a piece of endoplasmic reticulum
-lysis |
|
|
Term
What are the symptoms of rotavirus infection?
Are these symptoms more or less severe in children? |
|
Definition
-watery diarrhea
-nausea/vomiting
-symptoms are much more severe in children |
|
|
Term
| How is rotavirus diagnosed? |
|
Definition
| -discovery of viral particles in stool by ELISA or radioimmunoassay |
|
|
Term
| How is rotavirus infection treated? |
|
Definition
|
|
Term
-what kind of genetic material does Adenovirus possess?
-what is its capsule shape?
-does it have an envelope?
-how many proteins does the capsule have?
-what is special about the proteins at vertices? |
|
Definition
-DNA
-cubic icosahedral
-no envelope
->10 proteins
-the corner proteins are attachment proteins that cause hemagglutination |
|
|
Term
Where does Adenovirus assembly occur?
How does the virus leave the cell? |
|
Definition
Adenovirus assembly occurs in the nucleus.
It leaves the cell by lysing it. |
|
|
Term
| How is Adenovirus transmitted? |
|
Definition
-fecal/oral route
-eye contamination
-aerosol droplets |
|
|
Term
| What are the symptoms of Adenovirus? |
|
Definition
| -watery diarrhea that spontaneously resolves |
|
|
Term
What similarities do Caliciviruses (Norwalk virus) have with picornaviruses?
What differences? |
|
Definition
-both picornaviruses and caliciviruses are small, unenveloped viruses with single stranded positive RNA
-Caliciviruses have a bigger genome and special spikes on the surface |
|
|
Term
| What is one of the most common causes of viral gastroenteritis in adults? |
|
Definition
|
|
Term
How is Norwalk virus (norovirus) transmitted?
what are common settings for outbreaks? |
|
Definition
-fecal-oral route: often involving contaminated seafood and water.
-outbreaks are typical in group settings like cruise ships, schools, camps, etc.
-person-person transmission can occcur in these settings. |
|
|
Term
| Why is norwalk virus so infectious? |
|
Definition
-it has a very low infectious dose
-the virus is excreted in stool for several weeks after recovery
-it is resistant to inactivation by chlorine
-also resistant to drying |
|
|
Term
| What are the clinical findings of Norwalk virus infection? |
|
Definition
-sudden onset of vomiting and watery diarrhea
-low grade fever
-abdominal cramping
-self-limiting |
|
|
Term
| How do you diagnose/treat Norovirus? |
|
Definition
Norwalk virus general is diagnosed only clinical findings.
Treatment is supportive therapy. |
|
|
Term
What are the symptoms of amoebic dysentery?
(intestinal and extraintestinal) |
|
Definition
-can be symptomless
-INTESTINAL: abdominal discomfort, malaise, diarrhea or constipation, dysentery, fever
-EXTRAINTESTINAL: enlarged liver, fever, chills |
|
|
Term
| What is the most common complication of amoebic infection? |
|
Definition
|
|
Term
| How are amoebic infections diagnosed? |
|
Definition
-take 3 stool samples to find trophozoite or cyst
-serologic methods can work in extraintestinal disease
-DNA probes can tell you if findings are pathogenic E. hystolytica |
|
|
Term
| How do amoebas cause cell damage? |
|
Definition
-formation of amoebapores
-a lot like cytotoxic t-cells
-cell-cell contact
-mediated by lectin-like adherence molecules
-after contact protein enters and creates pore causing swelling and blebbing of cell |
|
|
Term
| What are some defining characteristics of protozoa? |
|
Definition
-single celled eukaryotes
-have two cytoplasm layers (ectoplasm and endoplasm)
-have a cytosome (mouth)
-reproduce by binary fission
-turn into cysts when stressed
-active form is trophozoite |
|
|
Term
| What are the major pathogenic protozoa? What are their clinical manifestations and target populations? |
|
Definition
-Entamoeba histolytica causes bloody diarrhea
-Giardia lamblia and Cyclospora cayetanensis cause watery diarrhea
-Cryptosporidium and Isospora belli cause diarrhia in immunocompromised folks |
|
|
Term
What does entamoeba histolytica cause?
What special population are often carriers? |
|
Definition
-amoebic dysentery and liver abscesses
-10% of the world are asymptomatic carriers- especially homosexual men |
|
|
Term
-What are the defining characteristics of E. histolytica cysts? precysts?
-how can you kill a cyst? |
|
Definition
-Cysts have four nuclei and are formed traveling down our colon
-precysts have two nuclei and ribosome aggregations called chromatoids
-chlorine will not kill a cyst- they must be boiled or filtered out |
|
|
Term
How many carriers of E. histolytica will develop infection?
What is the mechanism of infection? |
|
Definition
-10% of carriers will display symptoms.
-the amoebas invade mucosal walls |
|
|
Term
| What are the symptoms of E. histolytica? |
|
Definition
| Bloody diarrhea with flecks of mucus and blood accompanied by pain |
|
|
Term
| How is Entamoeba histolytica diagnosed? |
|
Definition
-trophozoites in stool
-if they have blood in them, they are pathogenic
-empty trophozoites probably mean the person is a carrier
-ulcers can be seen in sigmoidoscopy from the invasion of the amoebas |
|
|
Term
| what are some possible complications of E. histolytica infection? |
|
Definition
hemorrhage
Strictura
Ulcerative colitis
Peritonitis- perforation/leakage
Secondary infection
Extension outside bowel |
|
|
Term
-how do amoeba get to the liver?
-what do they cause there?
-what are the symptoms?
-are trophozoites or cysts found in the pus? |
|
Definition
-they get there via the portal vein
-they cause abscesses
-swinging fever, sweating, leukocytosis, right side pain
-only trophozoite are found in the pus |
|
|
Term
| There are two ways amoebas kill and eat cells: what are they and what are they specific for? |
|
Definition
-cysteine proteinases:digest collagen, elastin, laminin, fibronectin, IgA, and complement C3a & C5a
-Amoebapores:
Pore forming proteins
No receptor required
4a helix with disulfide bonds
Dna sequences like NK and T cells |
|
|
Term
| Amoebas downregulate our immune response in many ways: how? |
|
Definition
-inhibit monocyte locomotion
-inhibit oxidative burst
-inhibit complement activity (C8 can't activate C9- no MAC is formed)
-locally inhibits macrophages and lymphoctyes
-downregulate TNF-a and INF gamma, thus downregulating MHCII
-trophozoites are resistant to neutrophils- whose degranulation causes cell damage
- |
|
|
Term
| What are some important differences between bacteria and amoeba caused dysentery? |
|
Definition
BACILLARY DYSENTERY
-acute
-rapid onset
-fever/vomiting as well as diarrhea
-WBC count is 16-20,000
-causes cramps
-ulcer is surrounded by inflammation
-spontaneous resolution
AMOEBIC DYSTENTERY
-moderate infection
-not epidemic
-gradual onset
-only diarrhea
-WBC count around 12,000
-chronic disease
-cramping unusual
-ulcers are not surrounded by inflammation |
|
|
Term
| How does dientamoeba fragilis differ from entamoeba histolytica? |
|
Definition
-no cyst form
-two nucleii in active form
-causes milder mucousy diarrhea by irritating mucosa (not invasive) |
|
|
Term
| Which amoeba is just like E. hystolitica but milder. |
|
Definition
|
|
Term
Amoebas can be treated with Nitroimidazoles:
which ones? |
|
Definition
-Metronidazole (flagyl)
-Tinidazole (fasigyn) |
|
|
Term
| Amoebas can also be treated with. . . |
|
Definition
-Diiodohydroyquine (iodoquinol/enterosept)
-Diloxanid foruate (furamide) |
|
|
Term
| Some antibiotics can be used to treat amoebas- which ones? |
|
Definition
-Paromycin
-Tetracyline
(these have an indirect effect) |
|
|
Term
| How do nitroimidazoles work? |
|
Definition
-they reduce nitro groups to hydroxylamines that disrupt DNA
-used for anaerobic gram + cocci, clostridium, and enterobacteria |
|
|
Term
What are some characteristics of metronizadole?
What is a less toxic alternative? |
|
Definition
-absorbed from the small intestine
-excreted in all body fluids (may turn pee red)
-can cross placenta
-side effects:
nausea, vomiting, metallic taste, diarrhea
-contraindications: alcohol use, first trimester pregnancy
-causes tumors in rats and mice
-Tinidazole (fasigyn) is a less toxic alternative |
|
|
Term
| How should an asymptomatic carrier of amoebas be treated? |
|
Definition
Paromomycin
or
Iodoquinol
or
Diloxonide furoate |
|
|
Term
| How is amoebic colitis treated? |
|
Definition
Metronidazole 1st
then
Paromomycin or Iodoquinol |
|
|
Term
| How should a severe or extraintestinal amoeba infection be treated? |
|
Definition
Metronidazole first
then
Paromomycin or Diloxanide furoate |
|
|
Term
| What are some characteristics of mastigophora (flagellates)? |
|
Definition
-free living parasites
-cytosome (mouth)
-move by flagella
-axostyle (skeleton)
-trophozoites and cysts
-divide by binary fission
-many are commensal |
|
|
Term
| What are the defining characteristics of Giardia lamblia cysts and trophozoites? |
|
Definition
-trophozoites have two oval nucleii
-and four pairs of flagella
-cyst has four nucleii
-spread fecal-orally
-cause flattening of villi |
|
|
Term
| What are the manifestations of Giardia? |
|
Definition
-foul smelling steatorrheic stools
-alternate constipation
-malabsorption
-vitamin B defficiency
-slow development in kids
-mild- malabsorbance of d-xylose and lactose intolerance (normal jejunal biopsy)
-severe- impaired absorption of fat, vitamin B12 and d-xylose
(weird thick villi, increased crypt depth, increased cellular infiltrate in lamina propria, trophs visible, atrophy possible) |
|
|
Term
| How is giardia diagnosed? |
|
Definition
-ELISA of stool sample
-endoscopy
-string test (enterotest)
-microscopic examination of stool |
|
|
Term
|
Definition
-Metronidazole
-Tinidazole
-Furazolidone
-Paromomycin
-Quinacrine (atabrine, mepacrine) |
|
|
Term
What are the defining characteristics of Balantidium Coli?
What infection do they cause?
how are they treated? |
|
Definition
-Cilia!
-one tiny micronucleus
-cyst with huge kidney shaped macronucleus and micronucleus
-cause intestinal lesions
-tetracycline and metronidazole |
|
|
Term
| Who/what does balantidium coli infect? |
|
Definition
|
|
Term
| What is the largest human protozoan? |
|
Definition
|
|
Term
What are the four major types of protozoa?
How do they move/reproduce? |
|
Definition
-Sporozoa:
no special locomotion
asexual/sexual phases
-Rhizopoda
pseudopods
asexual only
-Ciliophora
cilia
asexual and conjugation
-Mastigophora
flagella
asexual |
|
|
Term
What are the four major types of protozoa?
How do they move/reproduce? |
|
Definition
-Sporozoa:
no special locomotion
asexual/sexual phases
-Rhizopoda
pseudopods
asexual only
-Ciliophora
cilia
asexual and conjugation
-Mastigophora
flagella
asexual |
|
|
Term
| 10% of American AIDS patients harbor which protozoan? |
|
Definition
|
|
Term
| 10% of American AIDS patients harbor which protozoan? |
|
Definition
|
|
Term
| What is the life cycle of cryptosporidium? |
|
Definition
| Oocysts release sporozoites which form trophozoites with lots of crazy intermediate stages |
|
|
Term
What are the clinical manifestations of Cryptosporidium in a healthy person?
In an immunocompromised person? |
|
Definition
-self-limited diarrhea, discomfort, weight loss
-sever diarrhea, weight loss, cramps, vomiting, fever |
|
|
Term
| What is the pathogenesis of Cryptosporidium? |
|
Definition
-enterotoxin causes inflammation of submucosa
-villi atrophy
-D-xylose malabsorption
-steatorrhea
-less lymphoid cells in Peyer's patches |
|
|
Term
| What is the treatment for cryptosporidium? (for which population?) |
|
Definition
-Nitazoxanide
-Paromomycine and azithromycin
-spiramycin
immunocompromised patients only |
|
|
Term
| What is the pathogenesis of cyclospora? |
|
Definition
-inflammation of lamina propria
-epithelial dissaray
-loss of brush border
-shortening of villi
-impaired D-xylose absorption |
|
|
Term
What are the symptoms of cyclospora infection?
How is it contracted |
|
Definition
-nausea, anorexia, cramps, watery diarrhea
-fecal-oral (contaminated water) |
|
|
Term
| How are both cryptosporidium and cyclospora diagnosed? |
|
Definition
Phase contrast microscopy
Autofluorescence under uv light microscopy
Ziehl neelsen’s staining
Acid fast staining
Safranin staining |
|
|
Term
| How is cyclospora treated? |
|
Definition
| trimethoprim and sulfamethoxazole |
|
|
Term
|
Definition
Flatworms
(include cestoda/tapeworms and trematoda/flukes) |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
scolex = ?
proglottids = ? |
|
Definition
| Scolex is the head of a worm, proglottids are the body segments |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| The Taenia solium (pork tapeworm) has what kind of scolex? |
|
Definition
| four suckers and a circle of hooks |
|
|
Term
| What is the life cycle of Taenia solium (pork tapeworm)? |
|
Definition
Live in intestine of those who eat undercooked pork containing larvae (cysticerci)
Larvae attach to wall of small intestine and then grow up
Eggs are passed in feces and eaten by pigs |
|
|
Term
| What is cysticercosis and what organism causes it? |
|
Definition
-when a human ingests a pork tapeworm egg from human fecally contaminated water or food- the larva may infect and encyst in the brain or eyes
-this is caused by T. solium |
|
|
Term
| What are the symptoms of T. solium infection? |
|
Definition
-can be asymptomatic
-adult tapeworm causes little damage, maybe some diarrhea and anorexia
-cysts in brain can cause bad neurological symptoms (headache, vomiting, seizures) |
|
|
Term
| How is T. solium diagnosed? |
|
Definition
-Discovery of proglottids with 5-10 uterine branches.
-ELISA is available
-surgery or CAT scan for brain cysts |
|
|
Term
| How is T. Solium treated? |
|
Definition
-Praziquantel
-Albendazole |
|
|
Term
| How does T saginata (beef tapeworm) differ from T solium? |
|
Definition
-Beef tapeworm doesn't cause cysticercosis
-beef tapeworm has no hooks (just suckers)
-has 15-20 uterine branches (as opposed to 5-10)
- |
|
|
Term
| What are the symptoms of T. sanginata? |
|
Definition
-usually mild- cramps/malaise
-proglottids may appear in stool or protrude down there |
|
|
Term
| What is the treatment for T. saginata? |
|
Definition
|
|
Term
|
Definition
|
|
Term
what symptoms do fish tapeworms present?
how is it diagnosed? |
|
Definition
-anemial possible from B12 malabsorption
-discomfort/diarrhea
-oval yellow/brown eggs in stool |
|
|
Term
| What are the general symptoms of all tapeworms? |
|
Definition
-abdominal discomfort
-hunger pains
-moderate eosinophilia |
|
|
Term
|
Definition
|
|
Term
What is unilocular hydatid cyst disease?
what causes it? |
|
Definition
Dog tapeworm embryos migrate to liver, lungs, bone, brain
Develop into fluid filled hyatid cysts
Usually one large cyst forms with lots of scoleces and daughter cysts w/in
If cyst ruptures due to trauma anaphylaxis can occur
-caused by echinococcus |
|
|
Term
| What is the defining characteristic of E. granulocus (dog tapeworm) |
|
Definition
-small
-only 3 proglottids
-prevalent in midde eastern shepheards |
|
|
Term
| Why do dog tapeworms cause such diverse clinical manifestations? |
|
Definition
| -the cysts can form anywhere and do specific damage in those locations |
|
|
Term
| How is dog tapeworm diagnosed and treated? |
|
Definition
Diagnosis mainly by serologic methods:Casoni skin test
Immunoblot
Lympoproliferative assay
-treatment by Albendazole and very careful surgery |
|
|
Term
| how is Hepatitis A transmitted? |
|
Definition
|
|
Term
| what population is at risk for Hepatitis A outbreaks? |
|
Definition
|
|
Term
| Is Hepatitis A an acute or chronic infection? |
|
Definition
| Acute (and self-limiting) |
|
|
Term
-What is Hepatitis A's capsid shape?
-is it enveloped? |
|
Definition
|
|
Term
| What is the mechanism of cell damage in Hepatitis A infection? |
|
Definition
| our immune response to it |
|
|
Term
-what kind of genetic material does Hepatitis A have?
-what family of virus is it? |
|
Definition
-positive single stranded RNA
-picornavirus |
|
|
Term
| What are the clinical manifestation of Hepatitis A? |
|
Definition
Acute onset of fever, chills, headache, fatigue, malaise, aches and pains
A few days later this progresses to anorexia and upper right abdominal pain
Then jaundice with pale stools and dark urine
Symptoms usually improve around this time although jaundice may increase for a few days and hang around for a few weeks
Complete recovery takes a few months
-kids may be asymptomatic
-very low morality |
|
|
Term
| What are some possible complications of Hepatitis A? |
|
Definition
-blockage of bile duct leading to prolonged jaundice (treat with corticosteroids)
-relapsing disease (immunologically mediated, unresponsive to meds) |
|
|
Term
| How is Hepatitis A diagnosed? |
|
Definition
-virus is shed in feces during incubation period
-serum, saliva, urine, semen
-serologic testing: IgM ~45-60 days after infection
-IgG indicates immunity/past infection |
|
|
Term
| What are typical Hepatitis A lab findings regarding liver enzyme levels? |
|
Definition
Increase in Alanine aminotransferase
Increase in Aspartate aminotransferase
Liver enzymes normalize after 6 months |
|
|
Term
| What kind of virus is Hepatitis B? |
|
Definition
|
|
Term
| What is the protein coat of Hepatitis B? |
|
Definition
|
|
Term
| What is special about the viral coat of Hepatitis B? |
|
Definition
it sometimes protrudes like a tail
-filaments and spherical particles found in blood |
|
|
Term
What kind of genetic material does Hepatitis B have?
Is Hep.B enveloped |
|
Definition
-a small circular DNA
-yes it is |
|
|
Term
Where does Hep. B replication take place?
What is special about it? |
|
Definition
-transcription happens in nucleus, protein assembly in cytoplasm, assembly in nucleus
-it occurs with an RNA intermediate |
|
|
Term
HBV has three surface proteins: what are they?
Antibodies to which one provide protection? |
|
Definition
M protein, L protein, S protein
-S protein |
|
|
Term
| Which blood cells bind to HBV? |
|
Definition
|
|
Term
| In what cells does HBV multiply? |
|
Definition
|
|
Term
Do adult HBV infections tend to be transient or chronic?
What about perinatal infections? |
|
Definition
-adults tend to be transient
-perinatal tends to be chronic |
|
|
Term
| What are some of the consequences of chronic HBV? |
|
Definition
-higher antigen levels
-10-25% fatality from cirrhosis or cancer |
|
|
Term
|
Definition
-Nucleoside analogues help prevent reverse transcription
-lamivudine
-adefovir
-pencyclovir
-Alpha interferon
-needle sticks should be passively immunized with HBIG |
|
|
Term
|
Definition
Serologic Methods-
HBsAg is a good marker of infection
HBsAb shows recovery/immunity
Anti-HBc IgM demonstrates acute infection
Anti-HBc IgG shows past or chronic infection
HBeAg shows active replication of viruses
HBV-DNA is the same but good for finding mutants
Used mostly for monitoring response to therapy |
|
|
Term
What is HDV's genetic material?
What is special about Hep. D? |
|
Definition
-small circular negative SS RNA
-it uses HBsAg for envelope and protection
-enhances all of HBV's sequelae |
|
|
Term
| How is Hep. C transmitted? |
|
Definition
|
|
Term
What is Hep. C's genetic material?
shape?
enveloped? |
|
Definition
-SS + RNA linear
-spherical
-enveloped |
|
|
Term
How is Hep C treated?
(note: it often causes chronic disease, cancer, and cirrhoses) |
|
Definition
Interferon is about 50% effective
Ribavarin might help in combination |
|
|
Term
How is Hep C treated?
(note: it often causes chronic disease, cancer, and cirrhoses) |
|
Definition
Interferon is about 50% effective
Ribavarin might help in combination |
|
|
Term
| Jaundice is caused by the accumulation of what in the blood? |
|
Definition
|
|
Term
What can make urine dark?
a)protein
b)unconjugated bilirubin
c)conjugated bilirubin
d)breakdown products of urea
e)all of the above |
|
Definition
| c)conjugated bilirubin (suggesting decreased secretion b/c of liver damage) |
|
|
Term
| What do elevated AST and ALT indicate? |
|
Definition
|
|
Term
How is leptospirosis transmitted?
a)animals to man via urine-contaminated water
b)animals to man via insect vector
c)animals to man via undercooked meat
d)sexual transmission |
|
Definition
| A)animals to man via urine contamination |
|
|
Term
| Which Hepatitis virus is in the same family as polio virus? |
|
Definition
|
|
Term
| Which Hepatitis viruses are spread by contaminated food/water? (and sexually) |
|
Definition
|
|
Term
| What are the primary characteristicis of clostridium? |
|
Definition
gram positive
anaerobic
spore forming rods |
|
|
Term
What causes tetanus?
how is it transmitted? |
|
Definition
-Clostridium tetani
-spore contaminated soil |
|
|
Term
|
Definition
| Clostridium Botulinum neurotoxin in food |
|
|
Term
| what can cause gas gangrene or food poisoning? |
|
Definition
|
|
Term
| what does clostridium difficile cause? |
|
Definition
| Pseudomembranous colitis after antibiotic use |
|
|
Term
| What is the pathogenesis of Clostridium tetani? |
|
Definition
-spore enters wound contaminated with soil
-exotoxin is released
-toxin travels to CNS where it blocks ganglioside receptors and blocks inhibitory mediators |
|
|
Term
| What are the clinical findings of tetanus infection? |
|
Definition
-muscle spasms/spastic paralysis
-lockjas
-characteristic grimace (risus sardonicus
-opisthotonus (back arching)
-exagerrated refelexes |
|
|
Term
| How is Clostridium tetani diagnosed? |
|
Definition
|
|
Term
|
Definition
-tetanus immune globulin
-metronidazole or penicillin
-respiratory support
-valium (muscle relaxant) |
|
|
Term
| What is the pathogenesis of Clostridium botulinum? |
|
Definition
| -toxin is absorbed from gut and travels to PNS by blood where it blocks acetylcholine release |
|
|
Term
| what are the clinical manifestations of Clostridium botulinum? |
|
Definition
-weakness and paralysis
-in infants who eat honey there may be weakness and floppiness, usually transient
-wound botulism is associated with skin popping |
|
|
Term
| how is botulism diagnosed? |
|
Definition
| -inject mice with serum from patient and see if it dies or find toxin in food |
|
|
Term
|
Definition
| trivalent antitoxin and respiratory support |
|
|
Term
| How is gas gangrene caused by Clostridium perfringens transmitted? |
|
Definition
-normal flora of colon/vagina
-war wounds/car crashes/septic abortion
-grows in traumatized skin
-produces alpha toxin
-enzymes produce gas in tissues |
|
|
Term
| what are the clinical findings of gas gangrene? |
|
Definition
-pain
-edema
-cellulitis
-gas in tissues
-hemolysis
-jaundice
-shock and death |
|
|
Term
| How is gas gangrene diagnosed? |
|
Definition
Smears of tissue and exudate show large gram + rods
Anaerobic culture than id by sugar fermentation
Double zone of hemolysis on blood agar
Egg yolk agar shows presence of lecithinase |
|
|
Term
| how is gas gangrene treated? |
|
Definition
| good cleaning of wounds and penicillin |
|
|
Term
| What is the most common cause of hospital-aquired diarrhea? |
|
Definition
|
|
Term
| What is the pathogenesis of Clostridium difficile? |
|
Definition
-Produces exotoxins A and B
Glucosylate a G protein active in actin filament polymerization causing cell death
-Chemotherapy can also cause this
-Rarely invasive of mucosa |
|
|
Term
| what are the clinical findings of Clostridium difficile? |
|
Definition
Diarrhea
Pseudomembranes on colonic mucosa
Fever and cramping
No blood, few WBCs
Toxic megacolon can occur |
|
|
Term
| How is Closridium difficile diagnosed? |
|
Definition
| see if toxin is present in stools |
|
|
Term
| How is pseudomembritis treated? |
|
Definition
-stop antibiotics
-switch to vancomycin or metronidazole |
|
|
Term
| Where does Vibrio cholerae like to live? |
|
Definition
|
|
Term
| what kind of bacteria is vibrio cholerae? |
|
Definition
| gram negative rod with no capsule, a single flagellum, and pili |
|
|
Term
Is Vibrio cholerae:
a)obligate anaerobe
b)aerobic
c)facultative anaerobe
d)microaerobic |
|
Definition
|
|
Term
| what kind of agar can isolate cholera? |
|
Definition
| thiosulfate citrate bile salts |
|
|
Term
| Which subgroup of cholera (based on O antigen) is most severe? |
|
Definition
|
|
Term
| What is the pathogenesis of V. cholerae? |
|
Definition
-fecal oral transmission or undercooked seafood
-Cholera toxin (choleragen)
Five polypeptide B subunits and central A subunit
B subunits bind to GM-1 ganglioside receptors on epithelial cells
Subunit A activates adenyl cyclase to produce cAMP
cAMP mediates hypersecretion of fluids and Cl- ions
-contains other toxins but cholera toxin is most important |
|
|
Term
| What are the clinical manifestations of cholera? |
|
Definition
-explosive watery (rice-water) diarrhea
-vomiting
-erosion of intestinal mucosa |
|
|
Term
| How is V. cholerae diagnosed? |
|
Definition
Stool sample
Clear rice-water or mucus containing stool is highly suspicious
(do not place in glycerol saline- it inhibits the cholerae)
TCBS selective agar
Oxidase positive
Serological testing neccesary |
|
|
Term
|
Definition
Rehydration!
tetracycline if neccesary |
|
|
Term
| What kind of bacteria is Campylobacter jejuni? |
|
Definition
curved gram negative rod
microaerophilic |
|
|
Term
| How is C. jejuni treated? |
|
Definition
|
|
Term
| What kind of bacteria is Yersinia enterocolitica |
|
Definition
|
|
Term
| What causes enterocolitis that is indistinguishable clinically from Salmonella and Shigella? |
|
Definition
|
|
Term
| What is the second most common human disease? |
|
Definition
|
|
Term
| What are some major characteristics of helicobactor pylori? |
|
Definition
-gram negative spiral rod
-microaerophilic
-many unipolar flagella
-catalase, oxidase positive
-produce urea
-produce H2S |
|
|
Term
| What is the pathogenesis of Helicobacter pylori? |
|
Definition
-Attaches to mucus secreting cells
Produces lots of ammonia from urea
Inflammatory response and above causes damage
Loss of mucus predisposes to gastritis an peptic ulcers
Ammonia also allows it to survive
Not found in stool/food/water/animals only in stomach biopsies
High levels in developing countries |
|
|
Term
| How is Helicobacter diagnosed? |
|
Definition
-gram stain of gastric mucosa
-can be cultured just like campylobacter (takes 5-7 days to grow)
-urea breath test (radiolabeled CO2)
-IgG antibodies in serum
-antigen in stool |
|
|
Term
| How is Helicobacter pylori treated? |
|
Definition
metronidazole or amoxicillin
pepto-bismol |
|
|
Term
|
Definition
|
|
Term
| what is the infective form of roundworms |
|
Definition
| the third molting- "filariform" |
|
|
Term
|
Definition
|
|
Term
| how do you treat pinworm (enterobius vermicularis) |
|
Definition
| mebendazole or pyrantel pamoate |
|
|
Term
|
Definition
|
|
Term
| in what populations is trichuris trichiura (whipworm) common? |
|
Definition
| institutionalized and kids |
|
|
Term
| with what infection is trichuris trichiura (whipworm) often copuled? |
|
Definition
|
|
Term
| what are the symptoms of whipworm infection? |
|
Definition
-mild = asymptomatic
-500-1000 worms yields ulcerative colitis in kids and IBS in adults
-Bloody/mucoid diarrhea
Weight loss/weakness
Abdominal pain and tenderness
Increases peristalsis and rectal prolapse |
|
|
Term
| How do you diagnose/treat trichuris trichiura? |
|
Definition
-find eggs in stool
-mebendazole |
|
|
Term
|
Definition
|
|
Term
| what is the largest intestinal nematode? |
|
Definition
|
|
Term
| where is roundworm often found? |
|
Definition
| warm countries and in areas with poor sanitation |
|
|
Term
| what happens when an roundworm patient gets a fever or anaesthesia? |
|
Definition
|
|
Term
| What are the symptoms of ascaris lumbericoides (roundworm) |
|
Definition
Allergic reaction may occur with reinfection
Intestinal phase: appendix obstruction and intestinal blockage
Tissue phase: pneumonia, cough, low fever, 50% eosinophilia (1-2 weeks after infection)
Vomiting and pain
Protein malnutrition
Or no symptoms |
|
|
Term
| How is ascaris lumbericoides diagnosed/treated? |
|
Definition
-diagnosis: eggs in feces
sedimentation concentration test
ElISA
-treatment: Mebendazole or pyrantel pamoate
(piperazine cytrate or Levazimole) |
|
|
Term
E. coli: Septic shock is caused by
a)fimbria
b)capsule
c)enterotoxin
d)endotoxin |
|
Definition
|
|
Term
E. Coli: recurrent cystitis is caused by
a)fimbria
b)capsule
c)enterotoxin
d)endotoxin |
|
Definition
|
|
Term
E. coli: neonatal meningitis is caused by
a)fimbria
b)capsule
c)enterotoxin
d)endotoxin |
|
Definition
|
|
Term
traveler's diarrhea (E. coli) is caused by:
a)fimbria
b)capsule
c)enterotoxin
d)endotoxin |
|
Definition
|
|
Term
The toxin of E. coli that is very similar to Shigella toxin is:
a)heat labile enterotoxin
b)heat stable enterotoxin
c)adherence promoting cyclase
d)verotoxin
e)exfoliative toxin |
|
Definition
|
|
Term
|
Definition
|
|
Term
| What is the best way to diagnose typhoid fever in the first week of infection? |
|
Definition
|
|
Term
| what is the pathogenesis of ETEC |
|
Definition
| heat labile and stable toxins |
|
|
Term
| what does ETEC usually cause |
|
Definition
traveler's diarrhea
-cramps
-watery diarhea
-nausea |
|
|
Term
| What is the pathogenesis of EPEC and what does it cause? |
|
Definition
-adherence factor
-acute diarrhea (watery and mucosy)
-vomiting
-fever |
|
|
Term
| What is the pathogenesis of EIEC and what does it cause? |
|
Definition
-invasion and destriction of mucosal epithelium
-causes dysentery similar to shigella
-blood, mucus, lymphocytes in stool
-fever
-cramps
-mostly adults |
|
|
Term
| What is the pathogenesis of EHEC and what does it cause? |
|
Definition
-shiga-like toxins (verotoxin)
-causes diarrhe (bloody)
hemorrhagic colitis)
-no WBCs in stool
-generally in kids and elderly
-from undercooked beef |
|
|
Term
amoebiasis may mimic:
a)ulcerative colitis
b)bacillary dysentery
c)appendicitis
d)epressive neurosis |
|
Definition
|
|
Term
amoebiasis may mimic:
a)ulcerative colitis
b)bacillary dysentery
c)appendicitis
d)epressive neurosis |
|
Definition
|
|
Term
| drugs of choice for acute intestinal amoebiasis are: |
|
Definition
| diiodohydroxyuinolone and tetracycline |
|
|
Term
an asymptomatic amoebic cyst passer should be treated with:
a)diiodohydroxyquinolone
b)metronidazole
c)paromomycin
d)no drug |
|
Definition
diiodohydroxyquinolone
paromomycin |
|
|
Term
| How does giardia cause malabsorption |
|
Definition
| it forms a mechanical barrier |
|
|
Term
| before dog tapeworm excision what should be done? |
|
Definition
| saline or formalin injected into the cyst |
|
|
