Fungi-Cestodes Deck

Question 1

Giardiasis (Giardia lamblia)

Answer 1

• aka “Beaver Fever” and “Backpacker’s Bug”
• usually self-limited, normally commensual protozoa
• Small Intestine, watery diarrhea.
• Symptoms of GI infection + bloating, excessive gas, and burping (often sulfurous)
• Malabsorption, structural and chemical changes to brush border.
• Watery diarrhea
• IgA deficiency?

Question 1

Chagas Disease (American Trypanosomiasis)

Answer 1

• Rural areas of Mexico, Central America, and South America;
• Flagellate protozoan, insect born zoonosis (kissing bug).
• Bite => Invasion of macrophages / nodular ‘chagoma’
• lesion => dissemination
• Acute illness may kill via myocarditis / encephalitis
• Chronic illness involes GI dysfunction and autonomic nerve degeneration and cardiac failure–years to decades

Question 1

Ascariasis (Ascaris lumbricoides)

Answer 1

• ingestion of food contaminated with eggs
• most common helminthic infection in humans
• usually ASYMPTOMATIC
• penetrate small intestine and travel to lungs
• can cause obstruction of pancreatic or biliary ducts-pancreatitis, suppurative cholangitis, and liver abscesses.
• Ascaris pneumonia (rare): larvae fill alveolar airspaces

Question 2

Mucormycosis (Zygomycosis)

Answer 2

• Environmental fungi, cause severe necrotizing, invasive infections that begin in sinuses and lungs (spores are inhaled)
• Rhinocerebral: creates a black crust with friable/hemorrhagic underlying tissue - spreads to vessels and brain. Tx = surgery, amphotericin B, may be fatal
• Pulmonary: Usually fatal, looks like aspergillosis (sepsis and infarction)
• Subcutaneous zygomycosis: In the tropics, hard inflamm. mass (infects subcutaneous fat) on shoulder, trunk, buttock, thigh

Question 2

Leishmaniasis (Leishmania spp.)

Answer 2

• Via sandfly bite.
• proliferate in macrophages–amastigotes
• Tropic/Subtropic, overcrowding.
• Skin soars, may progress to disseminated disease, splenomegaly.
• immunocompromised-diffuse cutaneous leishmaniasis.
• mucocutaneous late complication: disfiguring larynx, nasopharynx, anus, vulva (highly damaging)
• kala azar=visceral leishmaniasis “black sickness”-viscera overwhelmed by build up of infected macrophages–disrupts organ architecture with sheets of parasitized macrophages.
• kala azar is fatal: Requires treatment if disseminated.

Question 3

Coccidioidomycosis “Valley fever” “Desert Fever”

Answer 3

• “Valley fever” “Desert Fever”
• Coccidioides immitis or Coccidioides posadasii
• Endemic in certain parts of Arizona, California, Nevada, New Mexico, Texas, Utah.
• Flu-like, maculopapular rash,
• Begins with pulmonary infection (granuloma-caseous)–nodules form in lung with hemoptysis, then disseminates, can cause meningitis in immunocompromised.
• usually after pulomary infection, appearance of eryhthema nodosum (IgG deposits-allergic reaction in fat underneath skin)

Question 4

Paracoccidioidomycosis (South American/Brazilian Blastomycosis)

Answer 4

• similar to coccidiodomycosis + blastomycosis
• chronic granulomatous infection (with purulent exudates) starting with lung involvement–dissemination in immunocompromised to skin, oropharynx, adrenals, and macrophages of lymphatic system.
• central + south america
• usually acute, self-limited and mild disease

Question 4

Clonorchiasis / Liver fluke (Clonorchis sinensis)

Answer 4

• Asia, Vietnam, Korea
• spread by ingesting inadequately cooked freshwater fish
• flat and transparent adult
• lethal due to complications: biliary obstruction, bacterial cholangitis, pancreatitis, cholangiocarcinoma

Question 5

African Trypanosomiasis (Trypanosoma brucei rhodesiense)

Answer 5

• Tetse fly
• Acute febrile progresses to life threatening meningoencephalitis-3 to 6 months
• Humans only reservoir of T. brucei
• evade immune system by altering glycoprotein antigen coat–genetically determined pattern (not mutation)
• Disruption of sleep, neurological problems.
• Fatal if untreated

Question 7

Candida (albicans)

Answer 7

• Usually superficial (deep infections uncommon and life threatening)
• Endogenous flora, most common precipitating factor = antibiotic use. Yeast converts to invasive hyphae or pseudohyphae form.
• Limited to mucocutaneous sites:
  
  • Thrush = oral cavity, fuzzy white coat on tongue (maceration predisposes)
  • Vulvovaginitis = thick white discharge, itchy (antibiotics, preg., diabetes, steroids)
  • Sepsis and disseminated candidiasis = usually deadly (catheter, IV, dialysis)
  • Endocarditis = large vegetations (IV drug use)
  • Other surfaces include esophagitis, paronychia (nailbeds), diaper rash and intertrigo (opposed skin surfaces)

Question 7

Loiasis “African Eye Worm”

Answer 7

• Mango fly bite transmites loa loa (round worm), which travels to the conjunctiva, where it can be readily seen in patient.
• Does not cause blindness
• DO NOT give antifilarials–destructive inflammatory response (highly antigenic when worms dead).
• rarely lethal (sudden + diffuse cerebral ischemia)
• usually self limited with mild CNS involvement

Question 7

Schistosomiasis (Schistosoma mansoni, S. japonicum, S. haematobium)

Answer 7

• Most important human helminthic infection, very disabling.
• S. haematobium: Intense inflammatory response, damage to nearby tissue, usually Liver, GI, or bladder, where it causes granulomas and dysregulated growth (polyps in colon, sq cell carcinoma in bladder).
• Portal hypertension (Desposit egg in venules), esophageal varices (S. Mansoni +S. japonicum)
• Asexual reproduction in snail.
• Penetrates human skin as schistosomula.
• Lays eggs: These cause the inflammatory response.
• Diagnosed based on eggs in feces.
• Generally self-limited

Question 8

Trichinosis (Trichinella spiralis)

Answer 8

• Inadequatly cooked or encysted meat; PORK.
• Survives in human skeletal muscle, myositis (diaphragm, ocular muscles, tongue, intercostals, deltoids, gastrocnemius), calcifications
• Classic sign: periorbital edema, swelling around the eyes, which may be caused by vasculitis.
• Extreme eosinophilia (>50% of leukocytes)
• May have CNS or cardiac involvement

Question 10

Fascioliasis

Answer 10

• spread by eating contaminated vegetation (watercress) with cysts from sheep
• cysts liberate metacecariae that pass into peritoneal cavity–live in intrahepatic and extrahepatic bile ducts
• hepatic abscesses and granulomas
• induce hyperplasia of bile duct epithelium, portal and periductal fibrosis, and biliary obstruction
• Symptoms: eosinophilia, vomiting, acute gastric pain
• Fatal if untreated
• diagnosis: recovering eggs from stool or biliary tract

Question 11

Dermatophyte Infections (Microsporum, Epidermophyton and Trichophyton)

Answer 11

• obtain nutrients from keratin–common and benign
• Athlete’s foot or tinea pedis
• Ringworm of the body or tinea corpora
• Facial ringworm or tinea faciei
• Blackdot ringworm or tinea capitis
• Scalp ringworm or tinea capitis
• Ringworm of the hands or tinea manuum
• Ringworm of the nail, Onychomycosis, or tinea unguium

Question 12

Mycetoma

Answer 12

• chronic granulomatic + suppurative cutaneous disease-through breaks in the skin
• tropical workers–affect feet: MADURA FOOT
  
  • disfiguring skin infection–abscesses that combine–large abscesses with ulceration–purulent discharge-white or black.

Question 13

Blastomycosis (Blastomyces dermatitidis)

Answer 13

• Very similar to coccidiomycosis, granulomatous, but also suppurative pulmonary dissease–cavitary pneumonia and meningitis with cerebral abscesses.
• Endemic to Midwest, Mississippi river and Ohio river basins, and around the Great Lakes.
• Skin (>50%) and bones (>10%) are most common sites of extrapulmonary involvement.
  
  • skin lesions from disseminated infection resembling squamous cell carcinoma.
• Usually self-limited (1/3 of patients)

Question 13

Cryptosporidiosis (Cryptosporidium parvum)

Answer 13

• extracellular enteric infection
• most common diarrheal infection in HIV positive patients.
• self-limiting, unless immunocompromised
• AIDS patients, etc, develop chronic infection with persistent chronic diarrhea that can lead to death

Question 13

Primary Amebic Meningoencephalitis

Answer 13

• Naegleria fowleri “Brain eating ameoba”: free-living, soil ameba
• Rare, but almost always rapidly fatal: fulminant disease-fever, nausea, vomiting, headache to deterioration of mental status in matter of hours.
• invades via nasal epithelium/olfactory bulbs.
• Swimming pools
• Neti-pots (for cleaning out your sinuses)

Question 14

Cystic hydatid disease / Echinococcosis (Echinococcus granulosus)

Answer 14

• endemic in sheep, goats, cattle, and sheep dogs
• humans contaminated by dogs: ingest tapeworm eggs spread by dog in human living spaces
• cestode has suckers and hooklets facilitating attachment
• larva penetrate gut wall, enter bloodstream, disseminate into deep organs
• form large (hydatid) cysts containing brood capsules and scolices–lungs and liver.
• cysts can compress intrahepatic bile ducts–obstructive jaundice–cysts: palpable mass upper right quadrant.
• Major complication: cyst rupture and seeing of adjacent tissues–proliferating cyst number and causing pain and fatal allergic reactions (anaphalactic shock)

Question 15

Dracunculiasis / Guinea worm (Dracunculus medinensis)

Answer 15

• infection of connective and subcutaneous tissues
• transmitted by drinking water contaminated with intermediate host, crustacean of genus Cyclops
• year incubation: symptoms: systemic allergic reaction, blisters that burst upon contact with water with female worm partially emerging
• dead worms provoke intense inflammatory response

Question 16

Cutaneous Larva Migrans (“Creeping eruption”)

Answer 16

• spread through skin on contact (dogs and cats major source of of disease)
• severe, itching, inflammation

Question 18

Onchocerciasis / “river blindness” (Onchocerca volvulus)

Answer 18

• Transmitted by fly bite.
• Onchocerca volvulus is the nematode, which carries a bacterial endosymbiont: Wolbachia pipientis, which causes a severe immune response that can cause blindness.
• inlammatory response causes damage to cornea, choroids, retina

Question 19

Strongyloidiasis / Threadworm (Strongyloides stercoralis)

Answer 19

• penetrate human epidermis
• most cases asymptomatic, lethal disseminated disease in immunocompromised persons.
• reproduce in human hosts-autoinfection (rhabditiform larvae become infective filariform within host’s intestine and repenetrate perianal skin–new parasitic cycle
• Immunocompromised: autoinfection greatly increased-penetrate intestinal walls and disseminate leading to ulceration, edema, and severe inflammation leading to sepsis from gram(-) bacteria-FATAL

Question 21

Paragonimiasis / Lung fluke (Paragonimus westermani)

Answer 21

- spread through ingestion of uncooked crab - Korea, Philippines, Taiwan, China - peripheral eosinophilia-distinguishing factor against TB + eggs in sputum or stools - frequently misdiagnoses as tuberculosis

Question 23

Pinworm Infection (Enterobius vermicularis)

Answer 23

- infects appenix and large colon. - goes to perianal skin-lys eggs eggs: cause itchy asshole syndrome.

Question 25

Histoplasmosis

Answer 25

- Histoplasma capsulatum. - Primarily effects lung, typically SELF\_LIMITED in HEALTHY. - Intracellular, macrophages = \> granulomatous, may resemble TB. =\> caseous necrosis + calcifications. - Can dissemminate bone, spleen, liver, adrenal glands, mucocutaneous membranes--AIDS, hepatosplenomegaly (granulomatous deposits) immunocompromised--fatal,

Question 26

Cryptococcosis (C. neoformans) - encapsulated

Answer 26

- Inhaled- natural reservoir is pigeon droppings - Impaired cell-mediated immunity common (AIDS, hodkins disease, leukemia) - CNS = site of primary infection--meningitis. Also causes progressive pulmonary disease - Fatal without treatment - Proteoglycan capsule is critical for virulence, - stains poorly with H&E - stains with mucicarmine - India Ink stain of CNS infection

Question 27

Visceral Larva Migrans / Toxocariasis (Toxocara canis & T. catis) ## Footnote

Answer 27

- ingestion of fecal contaminated food (from dogs/cats) - hypereosinophilia, pneumonitis, hypergammaglobulinemia - cheif symptom: loss of vision in one eye. - usually Self-limited

Question 29

Pneumocystis jiroveci Pneumonia

Answer 29

- Inhaled, common in AIDS patients (probably latent endogenous infection), often fatal. - Trophozoites (yeast-like) reproduce in alveolar type 1 cells and form cysts and rupture - alveoli fill with frothy eosinophillic material; diffuse lung inflitrate. - Best seen with methenamine silver stains

Question 31

Taeniasis/Cysticercosis (Taenia solium)

Answer 31

- Taenia Solium = Brain Cysts - Ingestion of Larvae (Meat) =\> Gut Tapeworm - Pernicious anemia - Mostly asymptomatic - Humans shed eggs in fecal matter. - Ingestion of Eggs (Fecal) =\> Disseminated Cysts to muscle and brain - Eggs create a massive inflammatory response. “Swiss cheese brain” - heart arrythmias, infect retina-blindness.

Question 32

Sporotrichosis

Answer 32

- Rose Gardner's disease - accidental inoculation through breaks in skin from thorns piercing skin. - chronic granulomatous skin infection with suppurative center-necrosis and ulceration--lead to secondary cellulitis - can disseminate through lymphatic vessels-spread to joints and bone.

Question 33

Malaria (Plasmodium sp: P. falciparum, P. vivax, P. ovale, P. malariae)

Answer 33

- Mosquito-born, hemolytic, febrile illness. - obligate intracellular parasite-replicate, kill human cells - Equitorial regions (tropics) - P. falciparum tends to be worst. - Human reservoire; gametocytes are in human blood and taken up by mosquito - Reproduce sexually in mosquito = \> sporozoites - Trasmitting to human via bite; go to the liver and form merozoite, perform asexual division. - Merozoites can invade/multiply within/destroy RBCs. =\> hemosiderin-laiden Macrophages seen. - Hepatosplenomegaly - clumped, infected erythrocytes block blood vessels--hemorrhages, obstruction--acute renal failure with renal blood vessels, intravsascular hemolysis leads to hemoglobinuric nephrosis (blackwater fever)

Question 34

Aspergillosis

Answer 34

-spores (conidia) inhaled -Allergic bronchopulmonary aspergillosis: restricted to asthmatics, spores can germinate in airways and cause long-term antigen exposure → exacerbation and infiltrates -Aspergilloma (fungus ball): Occur in old TB cavities. Cavity wall is collagenous connective tissue with lymphs and plasma cells. Usually left untreated if asymptomatic. -Inasive Aspergillosis: Occurs when neutrophil count is low (steroids, leukemia). Produces lung and pleural infarcts, but often spreads to blood and causes disseminated infec tion and thrombosis. Usually fatal, antifungals may help.

Question 35

Lymphatic Filariasis/"Elephantiasis" (Wuchereria bancrofti)

Answer 35

- transmitted via mosquito bites - inflammatory parasitic infection of lymphatic vessels: lymphangitis and sometimes lymphatic obstruction - edema with thickening of the skin and underlying tissue-elephantiasis - Often unilateral, involving scrotum/leg - Occult filariasis (anti-filarial antibodies) produces tropical pulmonary eosinophilia--can lead to fatal pneumonia.

Question 36

Toxoplasmosis (T. gondii)

Answer 36

- obligate intracellular pathogen - mostly asymptomatic, problem for immunocompromised and fetus-necrotizing disease. - Undercooked pig meats, cat litter, cats shed oocysts in their feces. - Convert to tachyzoites inside intermeidate-host and replicate inside specialized vacuoles - Immune response causes conversion to bradyzoites, which are associated with cyst formation, especially in CNS and muscle. - Associated with developmental defects in fetus and neuropsychiatric disorders. - Encephalitis produced in immunocompromised hosts - Lymphadenopathy in immunocompetent hosts

Question 37

Amebiasis (Entamoeba histolytica

Answer 37

- Active form (trophozoite) in human and feces - Cyst form is usually ingested from environment / fecal oral. - Large Intestine, bleeding more likely. - Invasive =\> May feature bloody / leukocytes in stool, metastisis = \>Liver - ameboma: complication, when amebae invade through intestinal wall-inflammatory thickening of bowel resembling colon cancer. - IMPORTANT: anchovi paste liver

Question 39

Hookworms (Necator americanus, Ancylostoma duodenale)

Answer 39

- penetrate human epidermis on contact-enter venous circulation - Duodenale = Asia / Mid East / Africa - Americanus = Americas, Southeast Asia, Subsaharran africa. - GI inflammation, iron deficiency anemia - Most common cause of chronic anemia worldwide.

Question 40

Babesiosis

Answer 40

- Tick-born, malaria-like disease. - Typically non fatal (self-limited) in healthy; but immuncompromised/splenectomy =\> complications - Reproduce in red blood cells (hemolytic anemia), where they can be seen as cross-shaped inclusions (fourmerozoites asexually budding - Seen in Europe and North America

Question 41

Trichuriasis / Whipworm (Trichuris trichiura)

Answer 41

- ingested eggs in contaminated food, soil, drink - Live in the Cecum or upper colon--children especially susceptible - Invasion causes small erosions, focal active inflammation, loss of small amounts of blood - Usually asymptomatic - Heavy infestations causes cramping, abdominal pain, bloody diarrhea, weight loss and anemia

Question 42

Chromomycosis

Answer 42

- tropics and subtropics - barefooted agricultural workers - inoculation through skin--lesion(papule) and become verrucous (wart like with ulceration)