Microbio

Enlarged nuclei; HPV

Rabies

Herpesviruses

Come in 3's: MMR, & the 3 alpha-Herpesviruses (HSV-1, HSV-2, VZV)

Grows on Eaton's agar; no cell wall, so neither positive nor negative Gram staining. Cell membrane does contain cholesterol, though = the only one. "Fried-egg" colonies when grown on cholesterol-rich medium. Walking pneumonia = CXR looks worse than pt. High level of cold agglutinins (IgM Ab's): RBC's clump together when placed on ice.

N.meningitides: sepsis, adrenal insufficiency, DIC, death.

Corynebacterium diphtheriae, Pseudomonas

Only 1 gram-neg. "Nagging Pests Must Breathe": Nocardia, Pseudomonas, Mycobacterium, Bacillus

Detects Ab's against Rickettsia species, except for Q fever (Coxiella burnetti).

Only 1 gram-neg. "Can't Breathe Air": Clostridium, Bacteroides, Actinomyces.

Thrush (HIV/immunocomp, neonates, DM); diaper rash; vulvovaginitis (DM, antibiotics); endocarditis (IV drug users). Yeast w/pseudohyphae, but germ tube at 37C (remember, all the C fungi are yeast at some point).

• 1) Allergic bronchopulmonary aspergillosus. (IgE)
• 2) Fungus ball in lung cavity (mycetoma).
• 3) Invasive lung disease (immunocomp) -- often-asymptomatic pneumonia, but deadly.
• Mold w/septate hyphae.

Yeast w/pseudohyphae. Chronic meningitis & pneumonia. India ink (not very sensitive), latex agglutination.

Molds; mucormycosis. Pts w/diabetic ketoacidosis & leukemia. Frontal lobe abscesses, infarcts of distal tissue.

By Malassezia furfur. Hot, humid weather; some patches don't tan. Spaghetti & meatball = both hyphae & yeast.

Diffuse interstitial pneumonia in AIDS (otherwise, usually asymptomatic). Yeast. Silver stain.

Dimorphic, rose gardener = local pustule w/nodules along lymphatics.

Protozoan cysts in water -- bloating, flatulence, foul-smelling diarrhea (often seen in campers) -- but not bloody (no intestinal wall invasion). Metronidazole.

Single-celled eukaryotes. Forms: cyst (protected form that's infective) & trophozoite (active, feeding form)

Usually asympt in men. Women = foul greenish discharge, itching, burning. Can be infected multiple times b/c no immunity ever acquired (non-invasive organism).

• Starts as hard, red area = chagoma. Then, fever + heart (tachycardia) + CNS (meningoencephalitis).
• If progresses to chronic infect (years later), then Chagas' disease: dilated cardiomyopathy, mega-esophagus & -colon.
• Transmission: Reduviid (kissing) bug -- has wild animal reservoirs.

• Sleeping sickness -- West & East African, respectively. (East is more deadly...so if you have that version, then you're going to the E.R.) Transmitted by Tsetse fly.
• Recurrent fever (b/c of Ag variation), lymphadenopathy, somnolence, coma.

Sandfly. The protozoans (amastigote form) live inside macrophages. 1) Cutaneous form: 1 (or multiple) skin ulcers. 2) Visceral: hepatosplenomegaly, pancytopenia, spiking fevers & weight loss.

• 2nd most common malaria strain (remember FAVE). Cyclic fever, HA, hepatosplenomegaly/anemia.
• Relapse, b/c dormant form (hypnozoite) lies in liver. Chloroquine-sensitive. Use primaquine for prophylaxis (they're protected from chloroquine in liver).

Most infectious (and common?). Induces knob formation on RBC's --> sequestration in microvasculature --> infarcts.

• Sporozoites infect & grow in liver --> trophozoites --> schizonts --> release lots of merozoites, which infect RBC's. Inside RBC's, whole life cycle repeats... merozoites released again (hemolysis). Some merozoites become gametocytes, which mosquito takes up for mating.
• Resistance develops when ppl have different Duffy antigens (which malaria uses to bind to RBC's & get in).

Babesiosis = fever, hemolytic anemia (b/c the protozoan invades RBC's). Deer tick, northeastern US.

Severe diarrhea in AIDS pts (mild in everyone else -- travel, daycare). The cysts are visible on acid-fast staining. (Other acid-fast stainers: the bacteria Mycobacterium & Nocardia, the great TB mimicker!)

Cat feces & meat contain cysts. Brain: birth defects in fetuses, abscesses in HIV pts (HA, focal neuro signs, retinitis --> blind). A baby might be fine, but then in 20's: reactivation --> retinitis --> blind.

Dysentery. More common in developing countries (cysts in water, fecal-to-oral). Bloody diarrhea (when trophozoites invade intestinal wall), liver abscess/RUQ pain... but most infections actually asymptomatic.

• Foul play: Rapidly fatal meningoencephalitis. Ingest while swimming in fresh water (via cribiform plate).
• Dirty contact lenses: keratitis --> blind

• Tapeworms (mate in GI tract) + flukes.
• Tapeworms: T.solium, D.latum, E.granuilosus
• Flukes: Schistosoma, C.sinensis, P.westsermani

Enterobius, Ascaris, Trichinella spiralis, Toxocara canis (eggs in eggs)

• Roundworms: Strongyloides, Necator americanus (hookworm)
• Flukes: Schistosoma
• If you eat tapeworm larvae, then brain cysts.

Onchocerca (female blackfly), Loa loa (deer, horse, & mango flies), Wuchereria bancrofti (female mosquito)

Pinworm. Ingest eggs (food, or fecal-to-oral) --> mature in gut --> eggs hatch at perianal opening

Giant roundworm. Ingest eggs --> intestinal infection. Kids can get malnutrition, gut obstruction... but many people infected w/o much disease.

Ingest eggs (raw pork) --> larvae settle in skeletal muscle, periorbital edema (rarely, brain).

Larvae (in soil) enter skin --> intestinal infection: vomiting, diarrhea, & also anemia.

Hookworm. Step on larvae --> intestinal infection can cause anemia, b/c suck blood.

Skin inflammation & ulcers; found in drinking water.

River blindness; larvae (microfilariae) transmitted by female blackfly, & worms die in cornea. Also, "lizard skin" (thick, dry, dark pigment). The microfilariae can cause allergic rxns.

Skin swelling (can see worm crawling in conjunctivae!). Deer, horse, & mango flies.

Elephantiasis when worms die in lymph vessels --> fibrosis; takes 9 months or so. Female mosquito.

Eat eggs in food. Granulomas (cause blindness if in retina) & larvae migrating in organs.

• Pork tapeworm (ingest larvae in undercooked pork) --> intestinal infection.
• If you ingest eggs instead: neurocysticercosis -- mass lesions in brain.

Fish tapeworm. B12 deficiency --> anemia.

Dog tapeworm. Eat eggs --> cysts in liver, lung, brain. If fluid is released from these cysts, then anaphylaxis.

Mature larvae (cercariae) penetrate skin --> fever (Katayama), dermatitis --> Granulomas/fibrosis of liver & spleen (obv, can cause portal HTN). Africa & Asia, snail host.

Fluke (flatworm) in undercooked fish. Pigmented gallstones, cholangiocarcinoma.

Flatworm in undercooked crab meat. Lung inflammation/ 2ndary bacterial infection.