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Contrast inactivated poliovirus vaccine and live attenuated oral vaccine.
Inactivated Polio Vaccine (IPV)- killed virus that is injected. Applied in mid 1950's. Invented by Dr. Salk. Is acceptable for immunocompromised. No vaccine associated disease although there were some manufacturing mistakes. Disadvantages- cost, injection, poor mucosal protection.
Liver attenuated virus (OPV)- Developed in the 60's. Is easier to administer, is less expensive, induces mucosal immunity and systemic immunity (IgM and IgG). Invented by Sabin. Attenuated virus can be passed in the stool of vaccinees and infect contacts.
What is unique about the replication of (-) strand RNA viruses.
-replicate in cytoplasm
-viral replicase is a RNA dependent RNA polymerase which has a high rate of error, induces mutations
-Negative strand is copied to make more (+) strand molecules
-Positive strand RNA molecules can be 1) made into new viron particles 2)become mRNA molecules to amplify the infection in the cytoplasm 3)serve as templates for more negative strand synthesis
What risks are associated with the OPV vaccine?
OPV vaccine is passed in the feces such that immunocompromised individuals can develop the disease even without vaccination. Especially negative for humoraly deficient individuals. Now reccomendation is for IPV 2X doses and then follow with OPV 2x vaccination.
What are 3 pathology stains used to identify fungi?
Mayer's mucicarmine- highlights capsules of cryptococcus magenta
Gomori's methanamine silver stain used for all fungal species, stains fungi black
Period acid Schiff with diastase- stains fungi magenta.
What are the 3 genera of dermaphophytes?
Dermatophytes = fungi that use keratin as food source.
Epidermophyton
Microsporum
Trichophyton
What is the preferred food substrate for dermatophytes?
Keratin. Thus infections are of the skin.
What is the preferred food substrate for candida albicans?
Candida likes sugar and serum. High incidence of disease with high blood sugars of diabetes mellitus. Also common with pregnancy, BCP, CS therapy, antibiotic therapy, trauma, foreign bodies and immunosuppression.
What is the preferred food substrate for malassezia furfur?
M. furfur is lipophylic and can only grow in medium supplemented with lipids. Infection results in scaly patches with fungal distribution, hypopigmented patches due to azaleic acid production folliculiits, systemic infections and seborrheic dermatitis.
What is the classic KOH appearance of M. furfur?
"Spaghetti and meatballs"
Clinical presentation is grey patches, scaly, inflammatory with occasional areas of alopecia with a black dot pattern. This child's head has many broken hairs and his disorder is often referred to as "black dot ringworm". What is it?
Tinea capitis. Dermatocyte infection. Usually Trichophyton tonsurans or microsporum canis.
Your patient is a wresteler with an annular rash. There are Majocchi's granulomas (follicular abscess), some blisters, and overall a polycystic, concentrically arranged rings of scales covering a large portion of the body. What it it?
Tinea corporis (infection of non-hairy skin/ ring worm). Most often caused by trichophyton rubrum.
This man has a rash, an annular scaly erythema with intense itching on his inner thigh. There is no scrotum involvement, just lichenified leathery skin. What is it?
Jock itch aka tinea cruris. Most often caused by trichophyton rubrum.
This extremely common infection is characteristically referred to as "two foot one hand syndrome." Diffuse hyperkeratotic dry skin in intertriginous regions between the toes. What is it?
Tinea pedia caused by trichophyton rubrum.
This is the cause of 20% of nail infections. If the infection begins at the moon and moves down the nail in a proximal sugungual onychomycosis pattern what are you worried about? What are the other 2 presentations and what is the causal organism.
Onychomycosis (tinea unguium) is caused by trichophyton rubrum just like tinea pedis. If infection is coming from the moon be concerned about immnodeficency and test for HIV. The nail alone can be affected with a normal nail bed called leukonychia mycotica. Also distal subungual onychomycosis is when the infection invades from the distal edge of the nail and this is the most common presentation.
What is the microscopic/macroscopic appearance of candida?
Candida is a dimorphic fungus with a budding yeast phase and some hyphae. Microscopically the yeast is ellipsoidal with pseudohyphae. Macroscopicly there is a raised, cream colored opaque colony.
What are the patterns of infection with candidiasis?
mucocutaneous- intertrigo (folds of skin), paronychia (base of nail) onychomycosis .
oral candiiasis- thrush, perleche
GI- esophagitis
Genital- vaginitis, vulvitis, UTI
What is tinea versicolor and what causes it?
Tinea versicolor is a rash with either dark or light spots. Causal organism is M. furfur. Organism of lipophylic and infection causes yellow brown to dark brown scaly patches with a truncal distribution. Light patches are caused by azaleic acid production. Appearance is of "meatballs and spaghetti"
What are the ecological habitats of localized cutaneous fungal infections and how do they typically gain access to the body?
Localized cutaneous fungal infections are caused by soil saphrophygtes that are introduced into the skin by trauma.
This "cigar shaped yeast" is dimorphic with a yeast phase at 35-37 degrees and a mycelial phase where it is able to be grown on Sabourad's agar at room temperature demonstrating hyphae with conidiophores with conidia. Presentation is with an ulcer and lymphangitis. What sporotrichoid differential have you developed?
The causeal organism is probably sporotrichosis mostly sporothrix schenckii a subtype of coccidiomycosis. However other bugs with a similar presentation include atypical acid fast infections ie Norcardia and other bacterial infections like tularemia.
Note that in the hyphae form sporotrichosis have conidiophores bearing specialized spores called conidia.
How does a sporotrichosis infection present?
This is most common cause of localized fungal infections. Caused by trauma inoculating a soil saphrochyte. Most commonly a lymphocutancous form results 80% with a primary ulcer followed by lymphangitis and lymphadenitis. Children often have facial involvement (92% of the time). Also the fixed cutaneous form (accounts for 20%) with an ulcer that become verrucous without any lymphangitis.
What is a Majocchi's granuloma?
A tinea infection that has gone down inside the hair follicle.
What feature of the classic candida rash is "miller time"?
There are pustular satellite lesions away from the larger rash.
This dimorphic fungi is infectious from cats, peat moss and roses.
Sporotrichosis.
This fungi lives mainly on dolphins. Infection results in keloids. Endemic to tropical areas.
Lobomycosis.
On histological exam you note "Medlar bodies" aka copper penny like colonies. This disease results in the growth of a red papule into a nodule/verrucious growth or ulceration following trauma. Severe lymphatic infection/ elephantiasis can occur.
Chronomycosis- Medlar bodies/ copper penny appearance on histology. All of these yeast produce melanin resulting in the copper color.
This indistinctive purulent abscess following trauma is usually treated with surgical abrasion. On histology you note pigmented brown hyphae.
Phaeomycosis- purulent abscess with pigmented brown hyphae.
Your patients foot has numerous fistulas along with "grains" of fungi in a variety of colors. This particular infection is very slow growing and thus very hard to manage.
Eumycotic Mycetoma "Madura foot"
- slow growing
-fistula formation
Your patient has large intra-nasal polyps studded with white fungal grains. Where did he get the infection from and what is it?
Infection = rhinosporidiosis- large intra nasal polyps
Result from infection with organisms in water usually in tropical areas.
Your patient cleaned his acquarium and now has a primary infected ulcer after the initial small cut he recieved.
Protothecosis
What is a dematiaceous fungi? What are 3 different varieties?
Dermatiaceous = pigmented
Eumycotic mycetoma- variety of colors
chronomycosis- melanin/ copper
phaeomycosis- brown hyphae
What is mycotoxicoses? Give an example of this syndrome.
Mycotoxicosis= infection of toxic fungal products ie alkaloids.
St. Anthony's Fire- fungus that infects grains... ergot alkaloids are produced and when ingested cause alpha adrenergic block aid, necrosis, gangrene, severe hypotension.
List 5 dimorphic fungi.
Sporotrichosis
Blastomycosis
Coccidiomycosis
Paracoccidiomycosis
Histoplasmosis
This fungi is found in Mississippi Ohio River Valleys. Found in the soil and is generally acquired by inhalation causing pneumonia. When it disseminated it goes to skin, bone, prostate. Thick walled, broad based budding yeast.
Blastomycosis
This fungus is found in the southwest in the soil. Hyphae form grows rapidly with "alternating barrel shaped arthrospores." In the body they form large spherules of conglomerated yeast. Causes pneumonia when inhaled and is often fatal if disseminated.
Coccidiomycosis
Histologically this fungi has a micky mouse or pilot's wheel appearance due to the narrow based budding of the yeast. Acqurired by inhalation, when disseminated goes into adrenal glands/ mucosal surfaces. Found in South America (with coffee).
Paracoccidiomycosis
This fungi is found in caves in Mississippi/Ohio river valley. The hyphae are very thin and branch frequently. There is no capsule. Found inside macrophages on H & E. If it disseminates it attacks oral mucosa and adrenal glands.
Histoplasmosis.
- histoplasma capsulatum.
This yeast has a worldwide distribution and is found in soil and pigeon droppings. Often causes meningoencephalitis. What stain would you use to identify it?
India ink stain to visualize the capsule of cryptococcus neoformans, or as an alternative can also use mucicarmine (magenta)
This mold is found world wide, hyphae are acute angle branching ~45 degrees. It is acquired via inhalation and causes allergic bronchial reaction. Loves to make fungus balls in the lungs especially by colonizing lung cavitations from pre existing TB. Also likes IV sites.
Aspergillus.
This species of fungi perfers diabetics as they love high glucose and low pH and can even survive off of ketones in diabetic ketoacidosis. Infects blood vessels of sinuses. Grows rapidly with large ribbon shaped hyphae without septae. Branches at right angles.
Rhizopus and Mucor species of mucormycosis.
What is unique about the structure of pneumocystis jiroveci?
No ergosterol layer. Treat with bactrim as you can't use traditinoal antifungals.
What two anti-fungals cross the BBB?
fluconazole and flucytosine.
This antifungal blocks MT synthesis stopping mitosis. It works very slowly, and is used primarily for dermatophyte infections (follows fat and keratin) and has been mostly replaced by terbinafine.
Griseofulvin
MOA- blocks microtubule synthesis stopping mitosis
ADR- HA
Use -dermatophytes
This antifungal blocks synthesis of beta 1,3 glucans in the fungal cell wall and is fungicidal. Name two drugs in this class.
The Echinocandins are like candy blocking the synthesis of glucan (ie sugar).
Examples are capsofungin and micafungin which must be given IV.
This antifungal is used primarially for dermatophyte infections and occasionally for onychomycoses. It can be given orally or topically and the MOA is to block synthesis of ergosterol in a manner complementary to the azoles.
Terbinafine
1st line for dermatophyte infections
MOA- blocs synthesis of ergosterol
ADR- agranulocytosis
works slowly 3 months
This prototypical class of antifungals blocks synthesis of ergosterol (stops conversion of lanosterol to ergosterol) by blocking the CYP450 system in fungi.
The imidaoles/triazoles.
What are the side effects of the imidazoles/triazoles and what population are they contraindicated in?
ADR of azoles- gynecomastic (inhibit E2 breakdown via CYP450. Also cause hepatotoxicity.
Contraindicated in pregnancy- teratogens
Name two topical azoles and one that is commonly used for meningeal infections.
Topical- clotrimazole and miconazole are used with candidiasis and dermatophyte infections.
Fluconazole crosses the BBB and is used for meningeal infections.
What is the MOA of amphotericin B? What is the topical form called?
MOA of Amphotericin B is to bind to ergosterol and punch holes through the membrane.
Nystatin is topical amphotericin B used for vaginosis, thrush etc.
What is the main ADR with Amphotericin B?
Renal toxicity. Also hypotension, anemia, phlebitis, arrhythmias, fever.
Name 3 topical antifungals.
Nystatin, clotrimazole, mitoconazole
What two classes of antifungals have to be given via IV?
Amphotericin and Echinocandins are given IV.
What is the most serious ADRs with pentamidine?
Hypoglycemia can be life threatening if not recognized. also rapid administration via IV can cause release of histamine causing drop in BP, dizziness, HA, vomiting, tachycardia and SOB.
What is an alternative med to treat pneumocystis carinii pneumonia other then trimethoprim sulfamethoxazole?
Pentamidine. Also used for trypanosomiasis (sleeping sickness caused by trypanosoma brucei gambiense)
This drug is effective against PCP, toxoplasma gondii and malaria caused by P. falciparum. The main ADR is rash and nausea. What is it?
Atovaquone.
1st line drug for the treatment of nematode infections?
Benzimidazoles-
MOA- prodrug that inhibits microtubule polymerization inhibiting mitosis.
This broad spectrum anti-helmintic drug can only be given po and its MOA is acetylcholine receptor agonist at the NMJ. Often drug of choice in pregnancy due to poor absorption.
Pyrantel Pamoate.
PP for preg via po
Use of this drug is fantastic for most cestode and trematode infections with the exception of cysticercosis (by pork tapeworm) cytic hydatid disease (echinococcus) and fasciola hepatica (sheep liver fluke).
Paraziquantel
what is a major contraindication to the use of praziquantel?
do not use if ocular cysticercosis is present- causes irreversible damage to the eye.
What is the most dangerous species of malaria infections and why?
P falciparum as it infects all erythrocytes (both young and old) while P malariae infects old erythrocytes and P vivax and P ovale infect the young erythrocytes.
What is the drug of choice for malaria if they are sensitive?
Cloroquine.
MOA- concentrates in vacuoles, inhibits heme polymerization, generates oxidative stress.
More potent and less toxic then quinine although resistence is wide spread.
What biochemical disorder contraindicates the use of cloroquine in the treatment of malaria due to hemolysis.
glucose 6 phosphate dehydrogenase deficency.
What is the MOA for the drug used for cloroquine resistant malaria?
Give quinine/quinidine which works by inhibiting heme polymerization and causing oxidative stress. In severe illness do a loading dose via IV. After 48 hrs dosage should be reduced by 30-50% even if patient fails to respond to prevent toxic accumulation of the drug.
What is syndrome of ADR seen with the use of quinine?
Cinchonism- tinnitus, deafness, nausea, vomiting, rashes, visual impairments, hypotension, hypoglycemia
What alternative drug to quinine and cloroquine is known to cause CNS toxicity including HA, visual and auditory disturbances, dizziness and neuropsychiatric reactions.
Mefloquine.
This drug is often used in combination with atovaquone for treatment of MDR P. falciparum. MOA is via dihydrofolate reductase inhibitor.
Proguanil.
safe for treatment in kids
in high doses can cause vomiting, diarrhea, hematuria
What is the only drug that targets the hepatic stage of P. vivax and P ovale? What must you test for before administering this drug?
Primaquine.
MOA- unclear, inhibits e transport chain.
C/I- patients with low WBC as it can cause hemolysis or low WBC counts, always test patient for G6PD deficiency as it can be fatal!!!
What is the exception to the fact that most helminths don't replicate while inside the host?
Strongyloides can replicate inside humans while most other helminths are ingested as oocytes which hatch and mature and then release their eggs in the stool for the next dirt licker.
What subtype of bacteria is responsible for elephantiasis aka lymphocytic filariasis? What 3 worms have this symbiotic bacteria?
Wolbachia is the symbiotic bacteria living in side the worms that cause elephantiasis. Wuchereria bancrofti, Brugia malayi and Brugia timori are the 3 causal organisms.
What helminth is most likely to cause pathology by blood loss, which is more likely to cause mechanical obstruction?
blood loss = hookworm aka Ancylostoma duodenale and Necator americanus.
Obstruction = round worm aka Ascariasis.
What lab finding is most common with parasitic infections, worms or ova or allergies?
eosinophilia. >500 eosinophils per microliter (>0- 0.5 x 10 ^6)
This helminth is one of the largest that infect humans, up to 30 cm. Comes from soil and is ingested, penetrates sm intestine and often is coughed up and re-swallowed continuing to lay eggs. Dx is made by examining worms/ ova in stool. Major complaint is luminal obstruction especially of biliary tract.
Ascaris lumbricoides = obstruction, they are huge!
What helminth is responsible for cysticercosis?
Taenia solium (the pork tapeworm) causes cystericecosis while the beef tapeworm (Taenia saginata) causes a milder disease with only diarrhea.
Contrast infectivity with the pork tapeworm vs the beef tapeworm.
The pork tapeworm( taenia solium) can cause more serious infection and can also be transmitted fecal oral while the beef tapeworm (tinea saginata) requires an intermediate host.
How does the density of the uterine branches of the proglottids help you differentiate between pork taenia solium and beef taenia saginata?
More dense branching with beef taenia saginata (15-30) vs pork taenia solium (7-13)
This helminth presents like a slow growing tumor with an inflammatory reaction in surrounding tissues. It is caused by ingesting eggs from teh feces of carnivores which then hatch in the intestine and migrate to the liver and lung where tumor like hydatid cysts develop
Echinococcus granulosus (Hydatid Cyst)- treat with surgical removal
Your patient has Elephantiasis. What caused it?
Wuchereria bancrofti causes elephantiasis as male female worm couples lie in lymphatics obstructing drainage for up to 10 years.
This helminth is the agent of river blindness transmitted by the black fly in Africa. Blindness is caused by an immediate hypersensitivity reaction to dead or dying organisms.
River blindness is caused by Onchocerca volvulus.
What is common presentation for Hepatitis A virus?
HAV is an acute infection from a picornavirus transferred by fecal-oral transmission. Syptoms are acute with fever, malaise, anorexia, nause and abdominal discomfort, dark urine and jaundice. Recovery is complete with very low mortality ~0.2% although this is the most commonly contracted Hepatitis.
What Hepatitis Virus is a DNA virus while all the rest are RNA?
Hep B is DNA!! It's an enveloped hepadnavirus.
This type of hepatitis has a 10 fold higher mortality (~2%) then HAV although it also is acute, transmitted fecal orally usually due to contaminated water. However Fulminant hepatitis in pregnant women can cause mortality up to 40%!!
Hepatitis E Virus. Very similar to HAV but higher mortality especially if pregnant. No longer many infections in US with HEV.
Describe the HBV Antigens:
HBsAg
HBcAg
HBeAg
HBxAg
Describe the HBV Antigens:
HBsAg = surface antigen. Not infectious but indicates diagnostic marker of acute and chronic hepatitis. Recombinant vaccine has HBsAG particles.
HBcAg- Core antigen, marker of acute infection is HBcAG IgM.
HBeAg- associated with infectivity, early indicator of resolution of hepatitis if AntiHBeAG present.
HBxAg-viral regulatory protein, related to hepatocellular carcinoma.
What is responsible for the extensive liver damage with Hep B?
Hep B causes vigorous cytogoxic immune response directed against virus infected cells. Not due to virus killing cells suprisingly enough.
Who is at risk for Hep B infection?
Hep B is highly infectious only requiring 0.0001ml of blood to cause infection. Thus drug users, dialysis personnel, dentists, surgeons etc are all at risk. Especially since 0.1-0.5% of the US population is infected.
What antibody marker characterizes the chronic carrier state of persistent active hepatitis B?
HBsAg- surface antigen is present but there is an absence of anti HBsAg antibodies
What is the requirement for Hep D infection?
Hep D or Delta virus can only replicate in HBV infected cells. HBV provides HBsAg for packaging the delta viral RNA genome. Recall that the DNA virus of Hep B carries with it a reverse transcriptase to convert DNA to RNA. If HDV in addition to HBV occurs the mortality can increase up to 40%. However there is a good HBV vaccine that can prevent delta infections too!
Your patient has anti HBsAg. Are they infectious?
No they are non infectious. They have either had acute or chronic infection and mounted an adequate antibody response to fight it off.
This bug causes Lyme disease from tick bites.
Borrelia burgdorferi
This bug causes cat scratch fever.
Bartonella henselae
Tularemia is from tick bites, rabbits, deer and is caused by?
Francisella tularensis
Yersenia pestis causes ?
The plague is caused by yersenia pestis
A bite from a cat or dog resulting in cellulitis would raise your suspicion for what causal organism?
Pasteurella multocida - most common bacteria from cat/dog bites.
The classic triad of headache, fever and rash (vasculitis) are caused by what obligate intracellular parasite that needs CoA and NAD?
Rickettsiae causes HA, fever and rash. Treated with tetracycline.
Coxiella is an atypical rickettsia as it is transmitted by aerosol and causes pneumonia while most other rickettsiae are transmitted by an anthropod vector.
Contrast the rash of rickettsia and typhus.
Typhus rash is on the Trunk while Rickettsia ie RMSF is on the wRists.
Q fever is caused by inhalation of this rickettsial aerosol.
Q fever is for Queer as there is no rash and since it isn't called rickettsii in its name. The organism is Coxiella burnetii.
The rash begins on palms and soles, migrates to wrists, ankles then trunk with HA and fever. Along with this disease what other diseases have palm and sole rashes?
This is Rocky Mountain Spotted Fever caused by Rickettsia rickettsii. Other causal organisms for palm and sole rashes is coxsackievirus A infection, also known as hand foot and mouth disease, and syphilis.
Weil Felix reaction assay for rickettsial antibodies differentiates between what species?
The Weil Felix reaction is positive for typhus and RMSF but is negative for coxiella burnetii (Q fever).
Erythema chronicum migrans and an expanding bulls eye rash with central clearing makes what diagnosis.
Lymes disease from Borrelia burgdorferi which is transmitted by Ixodes tick. Treat with doxycycline. BAKE a key Lyme pie. B=bells palsy, A=arthritis, K= kardiac block, E= erythema migrans
This systemic mycoses is found in Mississippi and Ohio valleys. Mainly from Starlings or spelunking by batdroppings. Characteristic infection of macrophages as yeast or as thin branching septate hyphae with macroaleurispores.
Histoplasmosis. Usually causes pneumonia but can have mild flue like illness at first, chronic pulmonary infection with chronic Ca nodules or disseminated disease with oropharyngeal ulcers.
This systemic mycosis is found E of Missippi River and in Central America. Broad based budding of the yeast is characteristic. Can cause inflammatory lung disease and disseminate to skin and bone causing granulomatous nodules.
Blastomycosis= Big Broad Based Budding yeast
This systemic mycoses is found in SW US near California. Causes pneumonia, meningitis and "desert rheumatism". Spherule filled with endospores as yeast and as alternating barrel shaped athrospores as hyphae.
Coccidiomycosis- spherule with endospores and alternating barrel shaped athrospores.
This "captains wheel" budding yeast is found in rural Latin America. If there are mucocutaneous lesions noted these ulcers have characteristic rolled borders.
Paracoccidiomycosis
Contrast the angles of budding in Mucor and Rhizopus vs. Aspergillus as subtypes of opportunistic fungal infections.
Mucor = wide angles
Aspergillus = 45 degree angles (V shaped) and rare "fruiting bodies"
You isolate this cigar shaped budding yeast in pus and note nodules along draining lymphatics from the ulcer at the original site of the rose puncture. This "rose gardeners disease" is caused by what yeast?
Sporothrix schenckii is a dimorphic fungus that lives on vegetation. Treat with itraconazole or potassium iodide.
What is the most common opportunistic fungal infection for diabetics in ketoacidosis and leukemia patients?
Mucormycosis- irregular branching at wide/right angles, prefer low pH, saccharolytic, often in the sinuses.
What is unique about pneumocystis jiroveci such that it is treated with Bactrim (TMP-SMX) instead of antifungals?
There is no ergosterol in the cell wall of pneumocystis.
Name two topical azoles and describe their MOA.
Clotrimazole and Miconazole are both topical azoles that inhibit ergosterol synthesis via inhibition of fungal P450 system. Same MOA as ketoconazole, itraconazole and fluconazole which can be given po.
What is the MOA of Griseofulvin?
Griseofulvin works by inhibition of fungal microtubules causing failure of mitosis. Binds keratin and goes with it so works well for dermatophyte infections.
MOA of Flucytosine? What is unique about distribution?
Flucytosine crosses BBB into CSF for meningitis. Also causes bone marrow depression and hepatic dysfunction. However works well against Candida, Torulopis, Cryptoccus, Aspergillus via RNA and DNA synthesis inhibition.
MOA of Terbinafine?
Terbinafine inhibits oxidase in ergosterol biosynthesis. Can be given po but is inhibited in pregnancy. Used for dermatocyte infections.
What is the MOA of capsofungin
Capsofungin is used for invasive aspergillosis for salvage therapy. Serious as it has to be given IV to effect the beta 1,3 D- glucan synthesis inhibiting the cell wall (Recall that it is an echocandin)
You are treated with metronidazole if you drank the cysts of this protozoa. Most often campers affected. Can detect with immunoflourescence or ELIZA for antigens. The flagellate will affect the duodenum or jejunum and has a characteristic heart like shape with two nuclei.
Giardia lamblia.
This protozoal infection is sexually transmitted and found on wet mount when the motile pear shaped trophozoites are visualized.
Trichomonas vaginalis. Note incubation 5-28 days. Burning on urination with foul green/yellow discharge.
This protozoa has a specific Gal/GalNAc lectin that can be detected on immunoassay in addition to finding the cysts in stool with 1-4 nuclei. Infection with this organism can cause amebic liver abscesses, colonic abscesses and dysentery.
Entamoeba histolytica. Note that the Trophozoite internalizes RBCs as well.
This organism causes perianal pruritis.
Enterobius vermicularis aka pinworm
What are the ToRCHeS infections that are transmitted in utero or during vaginal birth?
Toxoplasma gondi-
Rubella
CMV
HIV/HSV type 2
Syphilis
What are the presenting symptoms of viral hepatitis?
nausea, vomiting, abdominal pain, loss of appetite, fever, diarrhea, light colored stools, dark urine, jaundice (elevated bilirubin).
What types of hepatitis are acute and are transmitted fecal to oral?
Hep A and E are acute and fecal-orally transmitted. "The vowels go through the bowels"
Why is the vaccine so efficacious for HAV?
There is only one serotype for HAV.
Note that if you have a patient who is infected you can give them both passive immunization (preformed antibodies against HAV) and the vaccine (active) as the incubation period is on average 30 days and as long as 50.
What serological tests indicate acute vs. cleared HAV infection? What about vaccination status markers?
Acute infection would be IgM anti HAV. IgG anti HAV would indicate that an infection has previously been cleared or that the individual has received the vaccine.
Contrast Hep E and Hep A. Which is more pathogenic? Is there a vaccine? What is the structure? etc...
Hep E is a calcivirus while HAV is a picornavirus. Both are SS + RNA genomes. Both only have 1 serotype, are spread fecal-oral and cause acute infections with long incubation periods ~30-50 days. However, HEV is more pathogenic and fatal then HAV and HEV can cause fulminant hepatitis in pregnant women with as high as 20% mortality. There is no vaccine and no treatment for HEV.
What is HDV missing from its SS circular RNA genome that it requires coinfection with HBV?
HDV steals envelopes and envelope proteins from HBV. It's defective and can't replicate on its own. Delta virus = Defective!
What protective immune response (antibody?) is effective against HDV?
Because HDV steals the envelope proteins from HBV it presents HBV surface proteins. Thus the HBV vaccine works to kill it if there are anti HBsAg present. However diagnostic tests look for antibodies against the delta core antigen to differentiate the two infections.
Your patient has HBV as indicated by anti HBsAg. How do you determine if this patient is infectious and you still need to treat them?
Infectious marker = HBeAg, Treat these patients so they don't spread the HBV but don't treat immunocompetent patients with the virus who aren't infectious as they will clear the virus on their own.
The following serological markers indicate what: HBsAG, no IgG anti HBsAg, no IgM ati-HBsAg, possibly some IgG anti-HBcAg.
HBsAg = spike proteins present
no IgG or IgM against them means the infection is chronic, that it hasn't been fought off yet. IgG anti-HBcAg would indicate exposure to the core (differentiating infection from vaccination)
For which types of hepatitis are there vaccines?
HAV- killed virus (active) and antibody (passive) vaccine available- 1 serotype= highly efficacious
HBV- HBsAg vaccine (active), antibody (passive) vaccines available. Give immediate HBV vaccine to infants of infected mothers, will prevent vertical transmission.
C/E = no vaccine
D= HBV vaccine is effacious.
When would you give someone with HAV both active and passive vaccination?
If the patient is asymptomatic and recently infected giving the passive + active will prevent spread of the virus giving a better outcome. If they are already symptomatic just give supportive treatment. They are already fighting off the vaccine. If they need protection before exposure just give active vaccine.
How do you treat active HCV infection?
Treat HCV with Ribavirin and IFN.
This bipolar staining organism is transmitted by fleas on rodents and is the cause of the plague. If you were to visualize the organism what would you see?
Yersenia pestis is the causal organism for the plague.It is a bipolar staining facultatively intracellular gram negative bacillis seen in sputum culture. Most often captured from AZ, CO and NM
Contrast Bubonic, Septicemic and Pneumonic plague.
Bubonic- most common form. Lymph gland swelling 2-5 days after bite from flea, 60-90% mortality. Lymph nodes become swollen and painful called buboes.
Septicemic plague- invasion of all organs, occurs after direct bloodstream innoculation or ingestion of plague ridden animal. Causes ecchymoses, petechiae and DIC.
Pneumonic- less common, transmitted human-human through aerosolized droplets. Highly infectious and 100% fatal if untreated. (Bubonic can infect lungs and become pulmonic)
What type of yersinia pestis infection had the highest mortality and the highest infectivity? What type of plague is this?
The pneumonic plague was easily transmitted with up to 100% mortality. It is a Demic plague as it is transmitted human to human.
What surface antigens of Yersinia pestis are responsible for its extra virluence and ability to get into non endocytosing cells to cause such mortality?
VW and F1 antigens are encoded by plasmids on Yersinia Pestis and are responsible for its infectivity.
Your patient works on a rabbit farm and was bit. He now has a ulceroglandular skin ulcer at the site of inoculation with this cysteine requiring organism. The well demarcated ulcer is localized with swollen lymphadenopathy. What is the bug and can this individual continue to spread the infection?
This rabbit farmer has Tularemia caused by Francisella tularemia a gram negative coccobacillus mostly found in Arkansas and Missouri. It requires cysteine for growtn causing a black well demarcated lesion and lymphadenopathy. Tehre is no chance for person to person spread unlike the plague.
Your patient is Mexican and sells unpasteurized goat cheese. She is suffering from relapsing remitting flu like symptoms. This can progress to Undulant Fever. How do you treat her and what is the bug?
Brucellosis is transmitted from unpasteurized cheese and contact with cows usually from Mexico. The infection with Brucella melitensis/canis causes remitting flu like illness.
Your patient is from Long Island and has erythema migrans, arthritis like ysmptoms, heart palpitations and a bulls eye rash with central clearing (from IL1 response). What is the zoonotic infection you are looking for in her blood?
Borrelia burgdorferi is the causal agent from Ixodes tick bites that causes Lymes Disease. Classic symptom is erythema migrans. B. burgdorferi is a spirochete but is difficult to visualize.
What are the 3 stages of Lymes Disease, and how do you treat it?
You can only treat acute Lyme disease with doxycycline. There isn't a vaccine yet and once the infection is full blown there is no good treatment. Long term antibiotics seem useless.
Stage I = localized infection (erythemia migrans begins)
Stage II- disseminated infection (meningitis, carditis, myositis)
Stage III- latent infection (chronic)
What is the vector for the 3 main Rickettsia infections:
Spotted Fever
Typhus Group
Scrub Typhus Group
Spotted Fever- wood tick
Typhus Group- lice
Scrub Typhus Group- chiggers
How do the rashes for the 3 main Rickettsial infections differ:
Spotted Fever
Typhus Group
Scrub Typhus Group
Spotted Fever- rash on extremities then centripetal spread to trunk
Typhus Group-rash on trunk spreads to extremities (centrifugal)
Scrub Typhus Group- no rash
What type of Rickettsial infection is caused by chiggers and doesn't cause a rash?
Scrub Typhus
What is the causal organism of Epidemic Typhus vs. Brill Zinsser Disease and Endemic Typhus.
Epidemic Typhus and Brill Zinsser Disease are both caused by Rickettsia prowazekii while Endemic Typhus is caused by R. typhi (less severe). All are from lice on humans and flying squirrels, show petecial centrifugal rash starting on trunk. Can cause pneumonia, circulatory collapse, renal failure up to 70% mortality if untreated.
This causal agent of Scrub Typhus is from chiggers. It doesn't present with a rash but does have an eschar at the site of the bite (like plague and tularemia). What is the organism?
Orienta tsuisugamushi causes Scrub Typhus while Epidemic Typhus is from R. prowazekii and Endemic Typhus is from R. typhi.
This organism is classified as a Rickettsiae but is a fusogenic, pathogenic obligate intracellular bacteria which is transmitted in dust. As little as 1 organism causes infection.
Coxiella burnetti causes Q fever. Inhalation of contaminated dusts from animals results in survival in phagolysosomes. Actually this bacteria needs acidic environment to replicate. Virluence factors include superoxide dismutase, catalase, phosphatase and LPS. Low mortality. Flu like illness.
What are the 2 major differences between Rickettsiae and Ehrlichiae?
Ehrlichiae infect phagocytic cells not endothelial cells and they replicate within phagosomes instead of within the cytosol.
Match the following Bartonella infections with their organism and describe the disease.
Cat Scratch Disease
Trench Fever
Oroya Fever
-B. henselae
B. bacilliformis
B. quintana
Cat Scratch Disease = Bartonella henselae
Trench Fever = Bartonella quintana (fever Q 5 days)
Oroya Fever = Bartonella bacilliformis (anemia from RBC invasion, splenomegaly hepatomegaly)
This disease is transmitted by sandflies in the Andes. It invades erythrocytes deforming membranes leading to severe infectious anemia and thrombosis. Diagnosis is by serology and finding inclusion bodies in erythrocytes. Splenomegaly and hepatomegaly are present. Original infection is infectious anemia followed by verruga peruana with angioproliferative skin lesions. What is it?
Oroya fever and verruga peruana (after 2-8 weeks) are caused by Bartonella bacilliformis. Treatment is Chloramphenicol, Tetracyclines and blood transfusion. Bartonella also causes cat scratch disease (B. henselae) and Trench fever (B. quintana)
This disease is from the human body louse and affects soldiers with a fever that comes every 5 days.
Trench Fever- from Bartonella quintana. Rash may or may not be present. Treat with doxycycline.
This disease is common and is from the scratch, bite, lick or flea bite from a cat. Disease is benign and self limited with a papule at site of entry, fever, lymphadenopathy. Treat with doxycycline.
Cat Scratch Disease from Bartonella henselae. (Other Bartonella infections are Trench fever from B. quintana and Oroya fever/verruga peruana from B. baciliformis)
This disease is a complicaiton of Bartonella henselae (Cat Scratch Dz) or Bartonella quintana (Trench fever). In immunocompromised individuals. Infection of endothelial cells, angioproliferative lesions develop resembling Kaposi's sarcoma and peliosis hepatitis with lesions of liver and spleen occur. Look at Silver stained sections and do PCR for diagnosis of this disease.
Bacillary angiomatosis - angioproliferative lesions resembling Kaposi's sarcoma
Peliosis of liver (caused by B henselae) resulting in liver and spleen blood cysts with fibromyxoid matrix containing bacteria. Immunocompromised are those affected. Complicaiton of Cat scratch disease or Trench fever.
Your patient goes walking in a cave (assumption of bat exposure), what two diseases are automatically on your differential.
Rabies- most commonly from bats in US and dogs worldwide
Histoplasmosis
This Rhabdovirus has a bullet shaped enveloped viron with - strand RNA genome. Zoonotic infection most commonly from bats in US.
Rabies. Replicates in peripheral neurons spreads retrograde along nerves to CNS. Vrius replicates in salivary glands and also causes encephalitis causing behavioral changes. Look for Negri bodies (eosinophilic inclusion bodies of virus particles in cytoplasm of infected neurons.)
Why is Monkeypox virus a misnomer? What type of virus is it and what is the clinical syndrome?
Monkeypox causes a rash that looks like small pox but is much less fatal. This orthopoxvirus causes outbreaks in Africa and is spread by rodents, squirrels and prarie dogs, NOT MONKEYs as the name suggests.
How does one acquire Hantavirus and what is the progression of the disease?
Hantavirus is from an enveloped bunyavirus -SS RNA virus (like orthomyxovirus). It is contracted by contact with rodent urine/feces. Presentation is mostly pulmonary, fever, myalgias, N/V, tachypnea, hypotension, crackles. Death 3 days after onset of pulmonary symptoms due to cytokine explosion in the lungs.
Arboviral diseases are usually caused by flaviviruses and alphaviruses. What is the viruses life cycle and why are humans dead end hosts?
animal is infected and becomes viremic, mosquito bites animal and the virus matures in the mosquito migrating to its salivary glands. Mosquito will usually continue transmitting the virus to other animals. If humans are infected the virus is usually cleared or the host dies, rare for human to become viremic enough to continue strain of transmission via arthropod vector.
Why can't we make a vaccine against Dengue fever since there are only 4 serotypes?
Having antibodies on board either from previous infection or vaccination actually enhance infectivity. Cross reactive non neutralizing antibodies against a second serotype facilitate infection of macrophages causing more hemorrhagic fever.
What vaccines are available for arboviral diseases?
Vaccines are made against yellow fever and Japanese encephalitis. No vaccine against dengue or West Nile.
What is the leading recognizable cause of aseptic meningitis?
Enteroviruses cause aseptic meningitis!
Describe the replication of + strand viruses ie picornavirus?
replication occurs in the cytoplasm
viral replicase has RNA dependent RNA polymerase and enzymatic proteins
RNA dependent RNA polymerase copies viral + strand into - strand RNA.
- RNA is copies to make more + strands
New + strands are made into viron particles, become mRNA to amplify infection in the cytoplasm and serve as templates for more - strand RNA synthesis.
How are teh + SS RNA non enveloped picornaviruses able to express more then one viral protein?
This is due to using viral proteases to chop up parts of their long polypeptide genome. Recall that RNA replicates in teh cytoplasm with virall encoded RNA dependent RNA polymerase.
What is VAPP (vaccine associated paralytic poliomyelitis)? Who gets it and what vaccine causes it ?
The oral vaccine aka Sabin vaccine is live and attenuated. It causes both IgG and IgA immunity and is easy to administer. The down side is that live virus can be reverted to wildtype and shed in the feces. This can then infect immunnaieve causing disease.
Which vaccine did Salk vs Sabin invent?
Salk invented injected polio vaccine while Sabin followed him by inventing the oral polio vaccine.
How common is VAPP?
1/ 500,000 first time vaccinees get paralytic disease from OPV
Contrast CJD with vCJD.
Creutzfeldt Jakob Disease- more common in elderly >55, present with dementia, rapidly progressive, worldwide
vCJD- young patients 20-40, behavioral changes, ataxia, insidious onset and longer course, England epidemic (M/M genotype)
What areas of the brain do the following human prion diseases hit?
CJD
FFI
Kuru
CJD- cortex
Kuru- cerebellum
Fatal Familial Insomnia- thalamic initiation of sleep
How do we know that prion diseases are caused by an infectious protein?
The pathological substance is not inactivated by UV light, DNAse, RNAse, or autoclaving, protease resistant.
PrP gene encodes prions. Normal product is PrPc, the spongiform form in PrPSc. The pathological form converts the regular alpha helix form. to the abnormal beta sheet.
T/F In the conversion of PrPC to PrPSc there is a alteration in the aa sequence and a covalent chemical post translational modification that causes the conformational variant that is protease resistant causing sponiform encephalopathy.
False. The AA sequence and convalent modifications are identical between PrPSc and PrPc. However there is a conformational variant changing the normal alpha helix conformation to a beta sheet.
The risk of sporadic CJD and growth hormone iatrogenic CJD is highest in what genotype as compared to vCJD?
V/V
V/M
M/M
at the PrP129 location
iatrogenic/sporatic = V/V
vCJD= M/M genotype most susceptible.
What are the symptoms and cause of Beriberi?
Beriberi is Thiamine deficency, B1.
Weightloss, Wet congestive heart failure. Dry beriberi peripheral neupathy
What are the symptoms of pellagra and the cause?
Pellagra is Niacin B3 deficency with diarrhea, dermatitis, dementia and death.
Contrast marasmus, kwashiorkor and cachexia.
Marasmus- malutrition, starvation, dry skin, emaciation, flaky skin, irratability, hunger.
Kwashiorkor- severe protein malnutrition, ascites, edema
Cachexia- wasting due to underlying illness ie TB or aids with atrophy of muscles and anorexia.
Rectal prolapse might indicate what type of worm infection? How about itching hands and feet?
rectal prolapse- whipworm (Trichuris)
itching hands/feet- hookworm (Necator)
What are the 4 most common causes of viral meningitis in children?
Enteroviruses- summer
Arboroviruses- (St. Louis/CA encephalitis, WNV)
Herpesvirus
Mumps- Winter
Neurocysticersosis is the most common CNS parasitic infection regardless of immunological status. What is the causal organism and where is it from?
Cystericercosis is from the pork tapeworm taenia solium
What CNS mass lesions would you be looking for in an immunocompromised individual?
Toxoplasma gondii is leading cause of CNS mass lesion (ring enhancing lesion) followed by primary CNS lymphoma (associated with EBV),progressive multifocal leukoencephalopathy will exhibit focal neurological deficits. Cryptococcus neoformans presents with subacute meningitis.
Other causes- TB meningitis, CMV, HIV, varicella, Aspergillus, Histoplasma, Listeria all can effect the CNS
Finding Gal/GalNAc lectin antigen in the serum or trophozoites or cysts in the stool or colonic mucosa along with colonic ulcers with rolled borders indicates what parasite?
That indicates Entamoeba histolytica.
-amebiasis, amebic liver abscess, abebic dysentery, or mostly asymptomatic.
Note colonic ulcers with rolled borders. Can disseminate to liver or lung causing cough.
Treat with metronidazole.
This heart shaped flagellate protozoan uncoats in the stomach and the trophozoites attach to the small intestines mucosa, especially jejunum or duodenum, causing malabsorption of fats and flatulence and greasy stools. No invasion of mucosa. Characteristic individual is camper drinking stream water.
Treat Giardia lamblia with metronidazole.
You suspect bacterial vaginosis but the d/c is not white and fishy its yellow and frothy. Since she doesn't have Gardnerella vaginalis you give her metronidazole to treat what protozoan infection?
Trichomonas vaginalis. No cytic phase. Trophozoites replicate by binary fission and are only sexually transmitted.
This diarrhea causing coccidia causes disease in immunocompromised patients. This acid fast bug attaches to the epithelium by the ileum and can be contracted by eating South American raspberries.
Cryptosporidium parvum. Treat with nitazoxanide.
What is the life cycle of plasmodium?
Mosquitoes inject sporozoites which infect liver cells.
Replicate causing a multinucleated schizont by asexual schizogony.
Each nucleus in the schizont becomes a merozoite which can then reinfect other liver cells or RBCs.
What 3 roundworm infections go to the lung?
Ascarias, Songyloides and Hookworm have worms that go to the lung are coughed up and swallowed to the stomach again.
Name associated Roundworm?
- perianal pruritis
- rectal prolapse, bloody mucoid diarrhea
- itching hands/feet, pneumonitis
- iron deficiency anemia, pneumonitis
-obstruction, pneumonitis
-perianal pruritis = pinworm
prolapsed rectum/ dysentery = whipworm
itching hands and feet and pneumonitis = strongyloides
-iron deficiency anemia, pneumonitis- hookworm
-obstruction, pneumonitis- Ascariasis.
This disease is caused by flatwoms which replicate in the bladder venous plexus shedding cysts into the urine. Dysuria, hematuria, HSM, lymphadenopathy, decreased liver function and eosinophilia are indicative.
Schistosoma. think urine problems due to worms in venous plexus of bladder. dysuria, hematuria.
Most commonly Schistosome haematobium from Africa causes urinary manifestations while S. japonicum from Asia and S. manosi from S. America and Africa reside in intestine and shed microphilaria into the feces.
Contrast the systemic diseases of Cystercosis, Echinococcus and Trichinella.
Cystercosis- from ingesting ova from porcine tapeworms. Can cause neurocystercosis if larvae penetrate CNS.
Echinococcus- ova from feces of carnivores hatch and migrate systemically replicating in tumor like hydatid cysts, slow growing.
Trichinosis- from undercooked pork or bear. Note myalgias, periorbital edema, conjunctivitis!
Treatment for roundworms? flatworms? protozoa?
roundworms = mebendazole "Bendy worms"
flatworms (fluke/schistomiasis) = praziquantel
protozoa = metronidazole
What protozoal infection has trophozoites with internalized RBCs?
Entamoeba histolytica
-pseudopodia (false feet)
chromotoid bodies (ribosomal aggregates)
tetranucleated cyst = infectious form
amebic liver disease/ amebic dysentery.
P. malariae, P. vivax and P. ovale are all susceptible to chloroquine. However vivax and ovale continue to live in the liver. What drug would you add to kill the liver holdouts?
Give both primaquine and chloroquine. Primarquine is the Prime drug to kill p vivax and p. ovale in teh liver.
P. malariae, P. vivax and P. ovale are all susceptible to chloroquine. However vivax and ovale continue to live in the liver. What drug would you add to kill the liver holdouts?
Give both primaquine and chloroquine. Primarquine is the Prime drug to kill p vivax and p. ovale in teh liver.
Most areas are now chloroquine resistant except in South America above the Panama canal. What would you use for treatment?
Primethamine/ sulfadoxine, Atavaquone proguanil, mefloquine, artemether.
Leishmaniasis is a blood borne flagellate transmitted by the sand fly. The promastigote infects phagocytes (macrophages). Treatment is with?
Sodium Stibogluconate kills Leishmaniasis via inhibition of protozoal PFK. Give IV , slow.
African sleeping sickness due to trypanosomiasis is due to infection via the trypomastigote. Treatment ?
Early on Suramin- IV, and Pentamidine- IV.
If CNS involvement- melarsoprol.
Recall that cyclic fevers are due to antigenic variation aka variable surface glycoproteins.
Sulfadiazine and pyrimethamine are used to treat what protozoal disease of concern in pregnant women and immunocompromised?
Toxoplasma gondii
-raw pork-cat feces
-oocyst is infectious
What antimalarial drug targets liver schizonts of P vivax and P ovale?
Primaquine targets liver schizonts but also give with chloroquine to kill erythrocyte forms as well.
Cinchonism results from this antimalarial drug including symptoms of tinnitus, vertigo, n/v/d, CNS HA and fever, hemolytic anemia, hypotension and BBB, Blackwater fever.
Cinchonism is caused by quinine which inhibits heme polymerase leading to toxic buildup of heme. Used with Fansidar (pyrimethamine/sulfadoxine) for P falciparum.
This drug is effective against most protozoa including E. histolytica, Giardia, Trichomonas vaginalis, Anaerobic bacteria (including Bacteroides and C. diff) and Gardnerella. Don't use with alcohol as will cause antabuse like effect.
Metronidazole!
In the diagnosis of whipworm and pinworm what blood work is a pertinent negative?
There is no eosinophilia. Rare invasion. Usually look at the stool for eggs or do scotch tape test.
This disease is transmitted y microfilariae via the black fly. Its only reservoir is humans and it is found in South America and Africa. Allergic reaction and intense puritis cause blindness.
Onchocerca volvulus causes River blindness due to an allergic reaction to microfilariae migrating through the dermis. Leads to darkened thickened lizard skin and if in the eye blindness. Treat with Ivermectin (also used for strongloides) VER = to see iVERmectin.
The filariae from Wuchreria bancrofti along the pacific islands and Africa are responsible for causing fibrous tissue plugs in lymphatic tissue. How do you treat it?
Elephantiasis and Filarial fever associated with W. bancrofti are treated with diethylcarbamazine.
The following 3 manifestations indicate what type of infection?
1. Swimmers Itch
2. Katayama fever with hives, HA, weight loss and cough for 3 weeks
3. Complications resulting in liver fibrosis
These are the signs of a flat worm infection by Schistomiasis. Major immuno-evasive mechanism is molecular mimicry. Causes eosinophilia. Diagnose via eggs in stool. Initial infection is by penetration of the skin while swimming by the tadpole like organisms.
Hydatid cysts in the liver and lung are caused by what tapeworm?
Echinococcus granulosis from the dog tapeworm. Eggs hatch in the intestine and larvae migrate to other organs and grow.
What drug is an alternative to mebendazole for Ascaris, Hookworm and Pinworm which is also perferred during pregnancy.
Pyrantel pamoate is a depolarizing NMJ blocker.
Give an example of organisms that would require standard precautions.
HIV, MSSA, Strep, Aspergillus
Give an example of organisms that you wold need to use airborne precautions vs those where you need droplet precautions.
airborne- TB, Measles, Varicella -even shingles
droplet- RSV, Influenza, Neisseria meningitides
When do you need to use contact precautions?
MRSA, VRE, MDR Actinobacteria, Pseudomonas
What two spore forming bacteria require hand washing with old fashioned soap and water?
Bacillus anthracis and C. difficle.
What do airborne precautions entail?
private room. droplets <5mm are spread via air.
Need > 6-12 air changes/hr
negative pressure room (air going in)
N-95 masks
What do contact precautions entail?
private room
gowns and gloves
transmitted by direct contact with patient and environmental surfaces
What do droplet precautions entail?
droplets > 5mm
private room
wear surgical mask
What do the following have in common: anthrax, plague, small pox, tularemia, viral hemorrhagic fevers, botulism toxin.
All bacteria or viruses that are considered potential bioterrorism threats.
For each CDC Category A agent for bioterrorism (easily transmissible, high mortality) explain what resources are available to counter that threat.
Anthrax, Plague, Tularemia, Smallpox, Viral hemorrhagic fevers, Botulism
Anthrax- new vaccine in trials, antibiotics are effective
Plague- no vaccine, antibiotics effective (give before and after exposure)
Tularemia- no vaccine, antibiotics
Smallpox- vaccine exists but not in large enough quantities, no antivirals
Viral hemorrhagic fevers- vaccines in development, no antivirals effective
Botulism-vaccine but not widely available, antitoxin exists but only lessens immediate severity and is not curative after binding to NMJ
How does intestinal bacterial flora differ between obese and lean individuals.
lean = bacterioides prevelent
obese = firmicutes
loose weight more bacterioides
What molecular methods are highly utilized for the analysis and mapping out of normal flora and its extreme complexity?
PCR sequencing of highly conserved 16S RNA.
What is quorum sensing and how do bacteria use it?
quorum sensing is when bacteria secrete signaling molecules proportionate to their population density.
examples: Lux I/R proteins in GN
oligopeptides in Gram positives
AI1 or Lux S between species.
Human signals Epi/NE
Effect bacterial behavior including biofilm production and toxin production
T/F Bacteria in biofilms divides more slowly and is more resistant to antimicrobials then planktonic bacteria.
True
What systemic antifungal should not be used against aspergillus fumigatus?
Use amphotericin B or echocandins but NOT fluconazole.
Where is coccidioides most commonly found.
Southwestern US, ie Arizona, Texas, Nevada
Where is Histoplasma most commonly found?
E of the Missippi along the Ohio River valley. (SE US states)
What is the life cycle of coccidioides and what is the infectious species?
Coccidioides is caught by inhalation of the infectious yeast form. It is them grown as hyphae (alternating barrel shape with septate hyphae). Replication occurs by forming endospores within a spherule. However spherules are not infectious.
What do humoral antibody tests or complement fixation tests tell you about fungal infections?
They are not protective and thus they serve as a marker for the level of infection. If erythrocytes added to the mixture after a few mintues don't lyse its considered a high titer as the complement has been used up against the fungi.
would you treat an immunocompetent host for a coccidioidosis pulmonary infection?
no if immunocompetent there is no treatment necessary.
Spread along lymphatic channels is typical for this cigar shaped yeast>?
sporotrix - sporotricosis
Protothecosis is caused by what? What is the microscopic finding.
Protothecosis is caused by inoculation with a pathogenic algae. Usually occurs with a traumatic event while cleaning acquarium. Often results in olecranon bursitis.
Microscopic findings of protothecosis include morulas - like a soccor ball.
Starlings disseminate this fungal infection in their feces commonly in caves. Microscopically found inside macrophages.
Histoplasmosis. Missippi and Phio River valley. attacks oral mucosa and adrenal glands. Often looks like flu but may end up with pulmonary calcified lesions.
This dimorphic fungi has right angle branching and prefers an acidic pH. Survival is grim about 50%. Where is this fungal infection usually noticed?
Mucocrmycosis usually effects the nasal turbines of immunocompromised or diabetics.
This SS + RNA picornavirus is spread by shellfish.
Hepatitis A. Virus shed in feces for first 6 weeks. Low mortality. Only acute infection. Incubation 15-50 days. Vaccine available only 1 serotype
This calcivirus is ss + RNA hepavirus. What individuals have the highest mortality?
+ RNA SS hepavirus- calcivirus is Hepatitis E. Fecal oral spread. Mostly from infected water. Causes fulminant hepatitis in pregnant women. Long incubation period up to 50 days. 20% mortality. No vaccine, no treatment.
This SS circular RNA virus needs to steal envelope proteins from another virus. Because of this "sharing" what vaccine will work against this virus?
Hep B virus works to kill Hep D due to shared envelope proteins. High mortality if co-infected. Hep B virus is an hepadna virus, ds DNA enveloped virus.
This enveloped flavivirus is ss + RNA. There is no vaccine and antibodies are not protective. It is the most common reason for liver transplants in the US although 1/3 are asymptomatic.
Hepatitis C is SS + RNA enveloped flavivirus. Ribavirin (causes hemolytic anemia) and Interferon help to clear majority of infections.
What ratio is elevated in alcoholics?
ALT/AST elevated ratio
This enzyme is elevated in pregnancy, bone injury and malnutrition in addition to liver injury.
Alk phosphatase, normal = 20-125
Bilirubin is elevated in liver disease, mono, hemolytic anemia. What is the upper range or normal?
0-1.3 mg/dL
What type of virus?
Hep A is a _______
Hep B is a _________
Hep C is a ________
Hep D is viroid like, whatever
Hep E is a __________
Hep A is a picornavirus, ss + RNA
Hep B is a hepadnavirus ds DNA, env
Hep C is a enveloped ss + RNA flavivirus
Hep D is viroid like, whatever
Hep E is a calcivirus, ss + RNA, naked
The entire category of Rickettsiae including spotted fever, thyphus group and scrub typhus are all treated with what?
deoxycycline, just like Lyme disease and Brucellosis.
How do you treat Plague and Tularemia (rabbits from AZ, MI)?
streptomycin.
Borriela brugdorferi is a spirochete which causes?
Lyme's disease. More prevalent in NE. Fever, erythema migrans, palpitations, arthritis, Bulls eye rash from IL1
This SS - RNA virus causes hemorrhagic fever with cytokine explosion in the lungs and renal symptoms.
Hantavirus from rodent urine / feces is a ss -RNA bunyavirus
These 2 filoviruses cause hemorrhagic fever.
Marburg and Ebola are filoviruses that cause hemorrhagic fever.
This orthopoxvirus is transmitted by african rodents causing a small pox like rash.
Monkey pox- orthopoxvirus
This corona virus has a bat reservoir and was or particular concern in China, causing pulmonary symptoms.
SARS is a corona virus.
This orthopoxvirus is transmitted by african rodents causing a small pox like rash.
Monkey pox- orthopoxvirus
Lassa virus is an ______ which causes hemorrhagic fever from _________
Lassa virus s an arenavirus causing hemorrhagic fever from rodent feces and urine.
This obligate intracellular bug infects phagocytes and multiplies as a morula. From hard ticks from deer usually in South central American and SE.
Ehrlichiae- intracellular, targets phagocytes, treat with tetracycline. Causes HME no rash but leukopenia, thrombocytopenia, liver damage.
Ehrlichiae is transmitted from? and infects what?
from hard ticks and infects phagocytes developing morulas. (similar to protothecosis- fish tank fungi in apearance)
This disease is from soft ticks and infects circulating neutrophils.
Anaplasma phagocytophilia. Same as Ehrlichiae but only infects neutrophils and is from soft not hard tick.
What two zoonotic diseases are transmitted by the sand fly?
Oroya fever (bartonella bacilliformis) and Leishmanis from the central american hemoflagellate infecting macrophages are both from sandflies.
What do the following have in commoin:
Dengue
Yellow fever
St Louis Encephalitis
West Nile Virus
Hepatitis C
These area all enveloped SS + RNA Flaviviruses transmitted by arthopod vectors aka arboviruses.
What viruses are under the category of Alphavirus.
Alphaviruses:
The equine encephalitises and Rubella
Although Rubells is not one that is transferred by the mosquito the others are. Alphaviruses are enveloped SS + RNA viruses.
This Reoviridiae is transmitted by the wood tick with a rodent reservoir and is primarially present in summer.
Colorado Tick Fever- Reoviridae, wood tick, summer.
This antibiotic is a prodrug that breaks DNA via pyruvate ferrodoxin oxidoreductas. It is effective against trichomoniasis, giardiasis and E. histolytica and pseudomembranous colitis.
Metronidazole is effective against giardiasis, E. holistica, pseudomembranous colitis and T. vaginalis.
This aminoglycoside antibiotic causes premature termiantoin of mRNA and can be used to as a luminal amebiaside, for leishmaniasis, and cryptosporidosis.
Paromomycin is an aminoglycoside effective against Leismaniasis and cryptosporidosis.
Toxoplasmosis and malaria are both killed by this DHF reductase inhibitor.
Pyrimethamine plus sulfadiaaine.
Pentamide has unknown MOA and is effective against? Major side effects?
PCP, Trypanosomiasis (sleeping sickness), and leishmaniasis although you must be careful about rapid IV administration of pentamide as it can cause histamine release and hypoglycemia.
Major drug of choice for inhibition of trypanosomiasis (sleeping sickness) and major side effect.
Sumarin ... inhibits parasite energy production, give IV, does not enter CNS. Can cause renal damage.
Sodium Stibogluconate is used IV against?
Sodium Stibogluconate is used against Leishmaniasis. IV slow infusion, can cause EKG changes.
Late stage sleeping sickness can only be treated by?
Eflornithine treats late stage Trypanosomiasis by inhibiting ornithine decarboxylase . Causes thrombocytopenia, leukopenia, diarrhea and BM suppression. Melasporol and Sumarin are less toxic drugs if Trypanosomiasis has not yet reached the CNS
Main MOA of anti hemilithic drugs?
Benzamidazoles are main anti worm drug which inhibit microtubule polymerization by binding B tubulin.
Best intestinal amebiaside
Mebendazole stays in the luMMMen
Tissue forms and larval forms of worms are best killed by this benzimidazole (binds to beta tubulin)
Albendazole is best for larvae and tissue forms but can't be given if there is liver disease.
This acetylcholine receptor agonist to NMJ causes paralysis of worms.
Pyrantel Pamoate causes worm paralysis by agonizing NMJ ACh-R.
This drug is used for cestode and trematode infections but can't be given if ocular cystercercosis is present.
Praziquantel is great for cestode and trematode infections but will damage the eye if cystercosis is present as it targets cell membranes.
Only drug for latent malaria.
Primaquine is the only drug for latent malarial forms. Always test for G6PD first.
Drug for use if cloroquine resistant.
Quinine is used if cloroquine resistant. Loading dose IV can be given but then must be reduced in 48 hrs.
What are category C agents of bioterrorism?
new emerging pathogens that are highly virulent and to which the population lacks immunity.