Fungi-Cestodes Deck Flashcards
Giardiasis (Giardia lamblia)
- 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?
Chagas Disease (American Trypanosomiasis)
- 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
Ascariasis (Ascaris lumbricoides)
- 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
Mucormycosis (Zygomycosis)
- 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
Leishmaniasis (Leishmania spp.)
- 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.
Coccidioidomycosis “Valley fever” “Desert Fever”
- “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)
Paracoccidioidomycosis (South American/Brazilian Blastomycosis)
- 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
Clonorchiasis / Liver fluke (Clonorchis sinensis)
- Asia, Vietnam, Korea
- spread by ingesting inadequately cooked freshwater fish
- flat and transparent adult
- lethal due to complications: biliary obstruction, bacterial cholangitis, pancreatitis, cholangiocarcinoma
African Trypanosomiasis (Trypanosoma brucei rhodesiense)
- 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
Candida (albicans)
- 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)
Loiasis “African Eye Worm”
- 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
Schistosomiasis (Schistosoma mansoni, S. japonicum, S. haematobium)
- 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
Trichinosis (Trichinella spiralis)
- 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
Fascioliasis
- 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
Dermatophyte Infections (Microsporum, Epidermophyton and Trichophyton)
- 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
Mycetoma
- 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.
Blastomycosis (Blastomyces dermatitidis)
- 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)
Cryptosporidiosis (Cryptosporidium parvum)
- 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
Primary Amebic Meningoencephalitis
- 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)
Cystic hydatid disease / Echinococcosis (Echinococcus granulosus)
- 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)
Dracunculiasis / Guinea worm (Dracunculus medinensis)
- 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
Cutaneous Larva Migrans (“Creeping eruption”)
- spread through skin on contact (dogs and cats major source of of disease)
- severe, itching, inflammation
Onchocerciasis / “river blindness” (Onchocerca volvulus)
- 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
Strongyloidiasis / Threadworm (Strongyloides stercoralis)
- 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