Term
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Definition
- Human urogenital tract
- Does not form cysts or any other environmentally durable form
- Causes Trichomoniasis in both sexes
- Only women are symptomatic
- Found only in trophozoite form
- Survive in liquid for 24 hours
- Survive on surfaces for an hour
- Adhere to vaginal epithelial cells in pH-dependent manner
- Transmitted by sexual intercourse
- Most common protozoan infection and second most common veneral infection
- Causes irritation, vaginal itching, odor, greenish-yellow dischage (vaginitis) in women
- In men: Urethritis or prostatitis
- Coorelations with prematurity, low birth weight, PID, and increases in HIV transmission
- Diagnosis: Wet mount or rapid serological test (dipstick)
- Treatment: Metronidizole for symptomatic women and their asymptomatic partners
- Tinidazole now approved and the best choice for pregnant women
- No vaccines
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Term
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Definition
- Extracellular parasite
- Attaches to and remains localized in the small intestine
- Reservoir hosts: humans, dogs, cats
- Biphasic life cycle: infective cyst or trophozoite
- Cysts are ingested from infected water/wildlife waste
- Fecal oral route-often seen in day care settings and insititutions
- Resistant to chlorination
- Only about half of infected patients are symptomatic
- Ingested cysts change into trophozoites in the intestines and attach by means of a sucker which holds them in place in the ileum
- Attachment results in inflammation and villous atrophy reducing absorptive capability
- Feed on glucose in the lumen and replicate by binary fission.
- The adult form and cysts form in the lower colon and are passed into the feces
- Infection can alter the ability to digest lactose by altering the production of lactase
- Non-bloody diarrhea
- Severe cases can cause malabsorption syndrome
- Abdominal cramps, foul smelling stools, flatulence and steatorrhea
- Symptoms can last 4 weeks
- Diagnosis-antigen test
- Treatment:Metronidizole
- Prevention: Boiling water for about a minute
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Term
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Definition
- 21 species
- Insect transmitted
- Host: human, insects
- Intracellular and extracellular phases
- Sand flys: flagellates form
- Cutaneous Leshmaniasis
- Ovbious lesion at the sand fly bite (can occur months later)
- Can lead to disfiguring facial lesions in bordering mucosa
- Common in areas of low socioecomic level
- Visceral Leishmaniasis
- Caused by L. donovani-complex species
- Infected cells migrate to the liver, spleen, and bone marrow
- Fever, weight loss, mucosal ulcers, anemia (malaria-like)
- Usually fatal if not treated
- Diagnosis by blood smear: Giemsa staining and PCR or by antigen serum dip stick
- Treatment with antimony (SB), Amphotericin B
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Term
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Definition
- Most deadly of human parasitic diseases
- 4 species: vivax, ovale, malariae, falciparum
- P. falciparum and P. vivax cause the most infections
- The asexual reproductive stage occurs in the human host where trophozoite (merozoites) initially multiply by binary fission within cells in the liver and re released to similarly multiply andfeed within RBCs
- Anopheles mosquito is definitive host
- Can be transmitted by transfusion or transplaentally
- Plasmodium injected by mosquito bite travel to the liver and infect hepatocytes.
- Multiply by binary fusion for 8-30 days without causing symptoms
- Released into the bloodstream where they enter and multiply in RBC
- Long lasting disease is caused when P. vivax and P. ovale take on alternate latent forms in the liver
- P. ovale relapsing fever at 3 day intervals
- P. vivax, P. malariae, P. falciparum relapsig fever at 2 day intervals
- Relapsing fever results from release of parasites from RBS which reinfect and then lyse new RBC at these intervals
- P. falciparum causes severe anemia, cerebral symptoms, renal failure, pulmonary edema, and death. More acute and dangerous
- P. vivax, P. ovale, P. malariae cause low levels of mild anemia and in rare instances splenic rupture and nephrotic syndrome. Can cause relapsing fever for more than 5 years
- Symptoms include chills followed by spiking fevers, sweats, anorexia, and joint pain. Leukopenia, anemia, and splenomegaly may also be present. Onset 6-14 days after infection
- Diagnosis involved examination of blood films or smears on glass slides for rings in RBCs or banana shaped gametocyte forms
- Chloroquine and primaquine are recommended treatment
- Prophylactic treatment with chloroquine or mefloquine
- No vaccines
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Term
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Definition
- "Known to change the behavior of rats and mice that are intermediate hosts, making them less fearful of cats"
- Cat is definitive host
- Asexual reproduction
- Sources of human infection include oocysts shed in feces of infected felines, infected meats
- More infective in warm weather but oocysts are durable
- Congenital transmission from other to fetus can occur
- Macrophages ingest the parasite which undergo intracellular replication and are transported throughout the body infecting many cell types
- Acute disease resembles mononucleosis and is self limiting
- 80-90% of infections are asymptomatic
- Congenital infections more often lead to symptomatic disease
- Hydrocephalus
- Microcephaly
- Intracranial calcification
- Chorioretinitis
- Particularily if the mother contracts the parasite for the first time during pregnancy
- Serological tests for IgM antibody
- Trophozoites can be seen in stool
- Treat with pyrimethamine and sulfadiazine
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Term
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Definition
- Most frequent cause of diarrhea in AIDS patients and those on immunosuppressive therapies
- Both asexual reproduction by binary fission and sexual reproduction of the parasite occur in the small intestine
- Oocytes are excrete in the stool
- Does not need an intermediate host and is transmitted by the fecal oral route
- Resistant to chlorination and can survive in the environment for months
- Infection involved repeated exposure to contaminated water including swimming pools
- Ingested oocytes release sporozoites that attach to the epithelia cells in the jejunum and mature into trophozoites
- Parasites are engulfed by epithelial cells but remain located on the lumen side (extracellular)
- Villi are disrupted in this transformation
- Immunocomptent individuals may show no symptoms or self limiting watery diarrhea.
- Others may experience more lengthy episodes lasting 2-4 weeks. This may include mucous in stools and abdominal cramping and low fever. Dehydration may occur
- Direct microscopy can identify acid-fst oocytes in the stool
- Serologicla tests are available
- Treatment is water and electrolyte replacement
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