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Micro J4 2


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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
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
Large and inhibit phagocytosis
Itraconazole, Amph B in tx failures
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
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
Pigeon poop
India ink of CSF, latex agglutination, culture
Pulmonary infxn, disseminated infxn includes meningitis, skin, osteomyelitis
No mold form (monomorphic)
Amph B + flucytosine; then Fluconazole; maintenance tx in HIV/AIDS pts
Diffuse perihilar infiltrates in CXR
Bronchioalveolar lavage
No serology
Alveolitis, pneumonia (PCP) – adheres to Type I pneumocytes
No ergosterol  can’t use normal antifungals
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
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  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)
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
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
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
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
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
Keratinases determine pathogenicity
4 clinical signs: inflammation, active borders, pruritis, scaling, (alopecia in tinea capitis)
Oral griseofulvin, itraconazole for tinea capitis
Tinea versicolor
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
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)
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
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
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)
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
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
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
Toxocara & Toxacaris (Ascarids of our pets)
Eggs hatch and migrate but don’t receive signals to grow to adults
Kids eat the eggs (PICA, just kids, dirty hands from pets)
Extreme eosinophilia
ï‚­ IgE
Serology (stool worthless b/c the larvae are not excreted)
Get puppies dewormed several times
Ocular larva migrans
Misdiagnosed as retinoblastoma
Can cause cataracts, retinal damage, blindness
Trichuris trichuria (whipworm)
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
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
No parasitic male worms – females undergo parthogenesis
Larva penetrate skin (then go to lungs, cough and swallow, etc)
Assoc w/ HTLV-1  IFN    TH2 response
SE Asia (US Veterans)
Autoinfection: life-long infection (>20% mortality), ï‚­ w/ steroids
Sxs: abdominal pain, diarrhea, urticaria, larval tracks
Enterobius vermicularis (pinworm)
Female lives in cecum, crawls out to perianal skin and lays eggs (mature in hours)
Perianal dermatitis  irritable behavior, bed-wetting
Scotch tape test
Mebendazole, Albendazole (give 2 doses 1 month apart) – treat entire cohort
Schistosoma mansoni
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  vasculature  liver  retrograde migration to mesenteric veins
Granulomas: TH2 driven, eosinophilia, chronic infxn usuallly downregulates size via IL-10/TGF-
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
Undercooked beef
Invade capillaries & muscle – benign
Cysticercus stage (head of scolex tape worm) consumed  attaches to intestinal wall
10 meters long!
Stool exam: proglottids (motile pumpkin seeds)
Taenia Solium – tapeworm
Like T. saginata (above)
Pigs – undercooked measly pork
Cysts in muscle
Neurocysticercosis – inflammatory response to cysts in brain  epilepsy
Stool exam: proglottids
Tx: corticosteroids (treat carriers); sanitations, condemn infected pork, pig vax in development
Echinococcus granulosis – tapeworm
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
Mosquito (larvae)
Female worm lives in lymphatics  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  more of a TH2 response
Tropical Pulmonary Eosinophilia
Annual mass tx, salt
Skin hygeine and exercise
Adult worms in subcutaneous nodules
Microfilaria migrate through skin
Black Fly
Ocular Damage (punctate ketatitis, sclerotization) & Retinal damage  blindness
Leopard skin: pruritis, severe itching, depigmentation
Hanging groin:  elasticity of skin
Immunosuppression   vaccine response
Serology or skin scraping
Guinea worm
Female worm causes an ulcer  emerges & person puts their leg in freshwater  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
Larvae in pig  undercooked meat
Wild game: especially bear, cougar
Larvae encyst in muscles (intracellular)
Inflammatory response  eosinophilia,  IgE
Periorbital edema
Muscle biopsy or serology
Entameoba histolytica
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
Oocyst in stool
Importation of exotic foods
Frothy discharge in 50% women
Low birth-weight babies
Tx. Metronidazole (some resistance)
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  scar
Mucocutaneous: progression from cutaneous, highly TH2 response, prob w/ 2Ëš infxn
Visceral: HIV related; spleen, liver, bone marrow  anemia, pancytopenia, weight loss
Blocks superoxide dismutase production (Gp63)
Chaga’s Disase
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
Tsetse fly (salivary gland)
Chancre  dissemination into bloodstream  lymphatics  CNS
Enlarged cervical lymph nodes (Winterbottom’s sign)
50% fatality w/o tx; 10-15% w/ tx
Waves of parasitemia: constantly changing antigenic presentation
Uses IFN- as a growth factor
CDC has tx – toxic

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