Micro J4 2
Terms
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- Histoplasmosis
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Bird/bat feces; demolition, construction, caves
Snowstorm CXR, coin-lesions, yeast in tissue
Acute or chronic pulmonary (emphesema), disseminated w/ HIV/AIDS
Ohio/Miss River Valley, opportunistic infxn
Itraconazole, Amph B in tx failures - Blastomycosis
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Inhale microconidia, dogs & men w/ prostate infxn
Broad-based budding, serology
T-cell response granulomas, acute pulmonary: weight loss, cavitations; pulmonary disseminated: bones, joints, prostate, CNS; chronic cutaneous
A-antigen
Large and inhibit phagocytosis
Itraconazole, Amph B in tx failures - Coccidiomycosis
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Inhaled arthroconidia
Serology, Accuprobe, hazardous to culture
Pulmonary infxn + erythema nodosum, tender nodules on anterior legs, joint pain
Southwest US, Mexico
Fluconazole, Amph B in tx failures - Candidiasis
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Inhalation, dirty hands
Culture invalid w/ catheter
Superficial, oral, vaginal, invasive
Normal flora
Broad spectrum Abx, transplant, immunosuppressed
Amph B, Fluconzaole (recent shift in pathogen distribution), Caspofungin/Micafungin - Cryptococcus
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Pigeon poop
India ink of CSF, latex agglutination, culture
Pulmonary infxn, disseminated infxn includes meningitis, skin, osteomyelitis
Encapsulated
No mold form (monomorphic)
Amph B + flucytosine; then Fluconazole; maintenance tx in HIV/AIDS pts - Pneumocystosis
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Diffuse perihilar infiltrates in CXR
Bronchioalveolar lavage
No serology
Alveolitis, pneumonia (PCP) – adheres to Type I pneumocytes
No ergosterol ïƒ can’t use normal antifungals
Bactrim - Penicilliosis
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Mold w/ red pigment & brush shaped conidiophore
Fission yeast (no budding)
SE Asia (Thailand)
Bamboo rat
Molluscum Contagiousum-like lesions on forehead/face and upper trunk
Microscopy or Culture (dangerous) or serology
Amph B; maintenance w/ fluconazole or itraconazole - Aspergillosis
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Mold infects lungs
Death rates in untreated high-risk = 80-90%
Avoid contact w/ foods, flowers, plants + use HEPA filter
Ubiquitous in evironment
Neutropenia, GVHD, steroid use = major risk factor
Becomes disseminated in immunocompromised ïƒ brain, heart, kidney, liver
CT: halo (early), air crescent (advanced)
Acute angle branching
Culture: commonly contaminated
Antigen detection: galactomannan (cell wall) – false + w/ certain therapies
Amph B, Voriconazole (new best tx) - Zygomycosis
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Sporadic
ï‚ incidence w/ use of Voriconazole
Ubiquitous in environment – common contaminant
Inhalation, ingestion or traumatic implantation
Rhinocerebral infxn (30-50% cases) – black discharge from nose (death w/in hours)
Pulmonary infxn – GVHD, neutropenic cancer pts
Cutaneous infxn – necrotizing fasciitis (must use aggressive surgical debridement + meds)
IV drug abusers – cerebral infxn
Broad, non-septate hyphae w/ wide angled branching
High dose Amph B - Sporotrichosis
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Dimorphic: mycelia in environment (daisy clusters with dark center), yeast at 37Ëš (cigar-shaped)
N America, African gold mines (splinters)
Traumatic implantation – rose bushes, sphagnum mosses
75% lymphocutaneous w/ cording effect
Fixed cutaneous mimics squamous cell carcinoma w/ pseudoepitheliomatous hyperplasia
Extracutaneous: bones, joints, meningitis in rose gardners
Tx: potassium iodide, Amph B, Itraconazole capsules - Chromoblatomycosis
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Chronic, indolent granulomas of feet/legs
Dimorphic black molds
Sclerotic bodies (non-budding) = copper pennies
Decaying wood, plants
Traumatic implantation (men get it more due to their occupational exposures)
Culture: gray mouse fur mold
Surgical resection for early lesions; Itraconazole for advanced - Mycetoma
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Pseudallescheria boydii = soil saprophyte
Triad: tumefaction, granules, draining sinus tracts
Does not spread to other organs
Ascospores (sexual reproduction)
Surgical resection for early lesions; Itraconazole for advanced
Resistant to Amph B - Dermatophytosis
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Trichophyton tonsurans: black-dot ringworm, endothrix growth, hair breaks off at scalp
Microsporum canis: multiseptate macroconidia (canoe shaped), Woods lamp positive, ectothrix
4-6 y/o day care/school issue
Communicable
Keratinases determine pathogenicity
4 clinical signs: inflammation, active borders, pruritis, scaling, (alopecia in tinea capitis)
Oral griseofulvin, itraconazole for tinea capitis - Tinea versicolor
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Malassezia spp
Meatball and Spaghetti
Budding yeast
Tan people have pale spots (hypopigmentation), pale people have dark spots (hyperpigmentation)
Tend to occur on upper trunk/back
Swimmers with lotions
Tx w/ selenium sulfide lotion - Anthrax
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Bacillus anthracis: aerobic, gram positive bacillus
Skin innoculation or spore inhalation
Virulence: protective antigen, lethal toxin, edema toxin, capsule
NO person to person spread = no respiratory isolation needed
Cutaneous: 20% untx pts die
Pruritic papule + necrotic black eschar + ulceration
Pulmonary: 80-90% untx pts die (1-42 days incubation)
Nonproductive cough
Hemorrhagic mediastinitis, pulmonary edema, septicemia, respiratory distress, shock, death
Tx: cipro, doxycycline + 1 of 2 other antimicrobials for 60 days (75 for prophylaxis) - Plague
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Yersinia pestis: aerobic, gram negative bacillus
Resist intracellular killing spread to regional lymph nodes
Virulence: F1 surface antigen
Rodents, rat fleas
4 Corners, SoCal
Bubonic: 2-8 day incubation
Tender bubo, sudden onset chills, fever, headache
No bubo = septicemic plague (25%)
Pneumonic: 2-3 day incubation
Cough + bloody sputum (productive cough)
ARDS, DIC, shock, multiorgan failure
Person to person spread = requires respiratory isolation
Tx: Streptomycin or gentamycin, chloramphenicol for meningitis - Cryptosporiosis
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Oocyst ingested (chlorine resistant)
Contaminated water, swimming pools, food
Summer outbreaks
Watery diarrhea ~12 days (>7 days think parasite)
AIDS: former defining illness, major weight loss, pre-HAART was never cleared
Stool sample – acid fast stain, immunoflourescence, antigen detection
70% population seropositive
No good tx
Reduce risk: boiled/filtered water, limited exposure to animals, feces - Toxoplasmosis
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Oocyst infectious in humans, herbivores
Cats, undercooked meat
Cysts maintained for life potential for reactivation
AIDS defining illness w/ Toxo encephalitis causing lots of morbidity/mortality
Transplacental infection: 1st trimester is worst: abortion, stillbirth, hydrocephalus
Serology: new infection with both IgG (ever infected) & IgM (acute infxn)
Bactrim - Giardiasis
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Flagellated protozoa
Ventral disc mediates attachment
Cyst resistant to environmental degradation – ingested form
Endemic in daycare
Fecal contamination of water or food, person to person spread (fomites)
Protracted diarrhea
Malabsorption syndrome + lactose intolerance beyond duration of infxn
Recurrent infxn common b/c trophozoites have highly variable surface antigens
Stool exam: cysts in stool, trophozoites in diarrhea
ELISA - Ascaris
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Helminth
Egg infective once larvae develop inside ingested release larvae into gut
Larvae enter circulation liver lung coughed up and swallowed grow to adulthood in gut
Eosinophilia
Asthma-like complaints, pneumonitis
Intestinal obstruction = medical emergency
Stool exam: female worms release 200,000 eggs/day
Serology: not useful
Tx: Mebendazole, albendazole; target microtubules
No immunity b/c antibodies only target the migrating larvae, adult worms too large - Visceral larva migrans
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Toxocara & Toxacaris (Ascarids of our pets)
Eggs hatch and migrate but don’t receive signals to grow to adults
Granulomas
Kids eat the eggs (PICA, just kids, dirty hands from pets)
Hepatomegaly
Extreme eosinophilia
ï‚ IgE
Serology (stool worthless b/c the larvae are not excreted)
Get puppies dewormed several times - Ocular larva migrans
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Granulomas
Misdiagnosed as retinoblastoma
Can cause cataracts, retinal damage, blindness - Trichuris trichuria (whipworm)
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Egg develops on ground & once larvae develop inside it’s infective
No tissue migration period (it goes straight to the intestines)
Survive 5-15 years
Rectal prolapse (pathognomonic)
Bone marrow suppression/anemia/anorexia due to TNF ï‚ (major nutritional impairment)
Stool exam: football shaped eggs
Mebendazole, Albendazole - Human hookworm
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Ancylostoma or Necator
Cuticular teeth/plates anchor worms to small intestine
Blood feeders anemia
Eggs hatch on the ground larvae sense heat/CO2 penetrate skin
Carried up respiratory tree coughed up and swallowed
Cutaneous larval migrans erythematous rxn + pruritis (characteristic tracks on skin)
Stool exam
Mebendazole, Albendazole - Strongyloides stercoralis
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No parasitic male worms – females undergo parthogenesis
Larva penetrate skin (then go to lungs, cough and swallow, etc)
Assoc w/ HTLV-1 ïƒ IFN ï§ ïƒ ï‚¯ TH2 response
SE Asia (US Veterans)
Autoinfection: life-long infection (>20% mortality), ï‚ w/ steroids
Sxs: abdominal pain, diarrhea, urticaria, larval tracks
Serology
Ivermectin - Enterobius vermicularis (pinworm)
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Female lives in cecum, crawls out to perianal skin and lays eggs (mature in hours)
Daycare/Fomites
Perianal dermatitis ïƒ irritable behavior, bed-wetting
Scotch tape test
Mebendazole, Albendazole (give 2 doses 1 month apart) – treat entire cohort - Schistosoma mansoni
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Fluke/Trematode
Adult worms exist as pairs (male has a groove that the female lives in)
S. japonicum: intestinal pathology
S. haematobium: hematuria, bladder cancer in Africa
Fresh water contamination
Snails release cercaria stage ïƒ vasculature ïƒ liver ïƒ retrograde migration to mesenteric veins
Granulomas: TH2 driven, eosinophilia, chronic infxn usuallly downregulates size via IL-10/TGF-ï¢
Hepatic Fibrosis (5%): absence of immune downregulation
Schistosomal/Cercarial Dermatitis: swimmers itch w/ exposure to marine estuaries/birds
Stool exam (Sm/Sj) or urine exam (Sh)
HIV: accelerated by schistosoma,  excretion of eggs = more in liver,  control of granulomas - Taenia Saginata – tapeworm
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Undercooked beef
Invade capillaries & muscle – benign
Cysticercus stage (head of scolex tape worm) consumed ïƒ attaches to intestinal wall
10 meters long!
Stool exam: proglottids (motile pumpkin seeds) - Taenia Solium – tapeworm
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Like T. saginata (above)
Pigs – undercooked measly pork
Cysts in muscle
Neurocysticercosis – inflammatory response to cysts in brain ïƒ epilepsy
Stool exam: proglottids
Tx: corticosteroids (treat carriers); sanitations, condemn infected pork, pig vax in development - Echinococcus granulosis – tapeworm
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Shepherds: close contact with dogs (harbor adult worms)
Hyatidosis: cyst in liver filled with solices (lots of tapeworm heads) = hydatid sand
Cyst rupture anaphylaxis
PAIR: percutaneous aspiration, injection, reaspiration of cyst - Wuchereria bancrofiti – filiariasis
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Mosquito (larvae)
Female worm lives in lymphatics ïƒ produces microfilaria that circulate in blood at night
Lymphatic filariasis: leading cause of disability worldwide + risk of 2Ëš infxn
Urogenital disease: acute hydrocele after adult worm death in spermatic cord lymph
Microfilaria downregulate immune response ïƒ more of a TH2 response
Tropical Pulmonary Eosinophilia
Annual mass tx, salt
Skin hygeine and exercise - Onchocerciasis
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Adult worms in subcutaneous nodules
Microfilaria migrate through skin
Black Fly
Ocular Damage (punctate ketatitis, sclerotization) & Retinal damage ïƒ blindness
Leopard skin: pruritis, severe itching, depigmentation
Hanging groin:  elasticity of skin
Immunosuppression ïƒ ï‚¯ vaccine response
Serology or skin scraping
Ivermectin - Guinea worm
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Female worm causes an ulcer ïƒ emerges & person puts their leg in freshwater ïƒ uterus bursts
Copepods eat the larvae
Unfiltered water
No effective drugs, prevent 2Ëš infxns
Wind the worm out on a stick – don’t break it off or else - Trichenila spiralis
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Larvae in pig ïƒ undercooked meat
Wild game: especially bear, cougar
Larvae encyst in muscles (intracellular)
Inflammatory response ïƒ eosinophilia, ï‚ IgE
Periorbital edema
Muscle biopsy or serology - Entameoba histolytica
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E. disbar is non-pathogenic twin
Virulence: Gal/GalNac Lectin mediates binding to intestinal mucins & inhibit complement
5 F’s: fingers, feces, food, fomites, flies
Cyst: impervious to environmental insult
Perforin homology
RUQ pain, fever, anorexia, abscess (liver, skin, brain – liquefactive necrosis)
Stool exam: ingested RBCs in trophozoites
Serology + in 70% of invasive intestinal infxn, 95% extraintestinal infxn - Cyclospora
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Oocyst in stool
Importation of exotic foods
Raspberries
Bactrim - Trichomonas
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Flagellated
STD
Frothy discharge in 50% women
Low birth-weight babies
Tx. Metronidazole (some resistance) - Leishmania
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Sand Fly – promastigote stage in fly’s gut causes it to regurgitate into human tissue
US troops in Middle East
Dogs are urban reservoir
Cutaneous: painful ulcer at inoculation site ïƒ scar
Mucocutaneous: progression from cutaneous, highly TH2 response, prob w/ 2Ëš infxn
Visceral: HIV related; spleen, liver, bone marrow ïƒ anemia, pancytopenia, weight loss
Serology
Blocks superoxide dismutase production (Gp63) - Chaga’s Disase
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Trypanosoma cruzi
Kissing bug/Reduviid
Raccoons & opossums in US
Bug excretes infective stage onto skin auto-innoculation by scratching
Chagoma: unilateral periorbital edema
Cardiac: acute tachyarrhythmias & chronic dilated cardiomyopathy death
Mega syndrome: myenteric plexus invasion dilation & stasis of esophagus & colon death
Concern: transfusions & transplants US blood supply will be screened for trypomastigotes (2007)
Probably not due to autoimmune response - African Sleeping Sickness
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Trypanosomiasis
Tsetse fly (salivary gland)
Chancre ïƒ dissemination into bloodstream ïƒ lymphatics ïƒ CNS
Enlarged cervical lymph nodes (Winterbottom’s sign)
50% fatality w/o tx; 10-15% w/ tx
Waves of parasitemia: constantly changing antigenic presentation
Hypergammaglobulinemia
Uses IFN-ï§ as a growth factor
CDC has tx – toxic