Parasitology Flashcards
Process of living together of 2 unlike organisms
Symbiosis
One species benefits without harming or benefiting the other
Commensalism
Both species benefit one another
Mutualism
One species benefits while harming the other
Parasitism
Lives inside the body of the host; Presence in host connotes infection
Endoparasite
Lives outside the body of the host; Presence in host connotes infestation
Ectoparasite
Need a host at some stage of their life cycle to complete development and propagation
Obligate Parasite
May exist in a free-living state but becomes parasitic when the need arises
Facultative Parasite
Establishes itself in a host it does not ordinarily live
Accidental or Incidental Parasite
Remains on host for life
Permanent Parasite
Lives on host for short period of time
Temporary Parasite
Free-living organism that passes through digestive tract with infecting the host
Spurious Parasite
Parasite attains sexual maturity
Definitive or Final Host
Harbors the asexual or larval stage
Intermediate Host
Parasite does not develop further to later stages
Paratenic Host
Allow life cycle to continue and become additional sources of human infection
Reservoir Host
Transmits parasite from one host to another
Vector
Transmits parasite only after it has completed its development
Biologic Vector
Mechanical or Phoretic Vector
Only transports the parasite
Process of inoculating an infective agent
Exposure
Establishment of infective agent inside host
Infection
Between infection and evidence o symptoms
Incubation Period (Clinical)
Between infection and demonstration of infection
Pre-patent Period (Biological)
Infected individual becomes his own direct source of infection
Auto infection
Infected individual is further infected with the same species leading to massive infection
Hyperinfection or Superinfection
E. histolytica trophozoites secrete cysteine proteases which digest cellular material
Enzymatic Interference
Plasmodium invades RBCs and cause rupture
Invasion and Destruction
D. latum competes with host for available supply of Vitamin B12
Nutrient Deprivation
E. histolytica produces suppressor factor that inhibits monocyte movement
Immune Suppression
Surface protein variation in T. gambiense
Antigenic Variation
E. granulosus carries blood group antigens
Host Mimicry
T. gondii multiplies inside macrophages
Intracellular Sequestration
Pseudopod-forming nonflagellated protozoa (Brownian Movement); Most invasive parasite among Entamoeba; Eukaryotic organism that lacks membrane-bound organelles; Fecal-oral route; Mature cysts; Trophozoites, mature cysts, immature cysts
Entamoeba histolytica
Mediates adherence
Lectin
For penetration
Amoebapores
For cytopathic effect
Cysteine proteases
Dysentery without fever; Flask-shaped colon ulcers
Amebic colitis
Associated with dysentery
Ameboma
Most common extraintestinal form;Anchovy sauce-like aspirate
Amebic liver abscess
Treatment for cyst carrier state
Diloxanide furoate
Treatment of Amebic colitis
Metronidazole
Treatment of Amebic Liver Abscess
MetronidazolePercutaneous drainage for nonresponders
Flagellate that lives in the duodenum, jejunum and upper ileum; Falling leaf motility; Simple asexual life cycle; Covered with variant surface proteins
Giardia lamblia
Abdominal pain, diarrhea and excessive flatus, smelling like rotten eggs
Acute Infection of Giardia lamblia
Constipation, weight loss and Steatorrhea
Chronic Infection of Giardia lamblia
Treatment of Giardia lamblia
Metronidazole
Opportunistic intestinal protozoa; Undergoes schizogony and gametogony; Autoinfection in immunocompromised patients; fecal-oral route; thick-walled oocysts
Cryptosporidium parvum
Treatment of Cryptosporidium parvum
DOC: Nitazoxanide
Urogenital protozoan; Exists only as a trophozoite; Pear-shaped, flagellated trophozoites; Sexual intercourse transmission; “Pingpong” transmission
Trichomonas vaginalis
Watery, foul-smelling, greenish vaginal discharge, accompanied by itching and burning; Strawberry cervix
Trichomoniasis
Treatment of Trichomoniasis
Single oral dose of 2 grams (4 500mg tablets) of Metronidazole
Blood and tissue sporozoa; Most important parasitic disease in man; Asexual life cycle consists of shizogony and gametogony; Sexual life cycle involves sporogony; Bite of infected female mosquito (Anopheles flavirostris minimus)
Plasmodium spp.
Recurrence of symptoms after a temporary abatement; Seen in P. falciparum and P. malariae
Recrudescence
Return of a disease after its apparent cessation (1-6mos) due to reactivation of hypnozoites; Seen in P. ovale and P. vivax
Relapse
Punctate granulations present in red blood cells invaded by P. ovale and P. vivax
Schuffner Dots
Coarse granulations present in red blood cells invaded by P. falciparum
Maurer Dots
Fine dots present in red blood cells invaded by P. malariae
Ziemann Dots
Paroxysmal fever with malaise and bone pains, hemolytic anemia, jaindice and splenomegaly; cerebral malaria (malarial or Durck granuloma); Acute renal failure (blackwater fever); Septic shock (algid malaria)
Malaria
Drug Therapy: Chloroquine-sensitive P. falciparum and P. malariae infections
Chloroquine
Drug Therapy: P. vivax and P. ovale infections
Chloroquine + Primaquine
Drug Therapy: Uncomplicated infections with Chloroquine-resistant P. falciparum
Quinine + Doxycycline/Clindamycin
Drug Therapy: Severe or complicated infections with P. falciparum
Artesunate + Doxycycline/Clindamycin or Mefloquine/MalaroneORQuinidine gluconate
Drug Therapy: Chloroquine-resistance
Mefloquine + Doxycycline
Drug Therapy: Eradication of Hypnozoites
Primaquine
Drug Therapy: Severe cases or pregnant
Quinidine or Quinine
Prophylaxis: Areas without resistant P. falciparum
Chloroquine
Prophylaxis: Areas with chloroquine-resistant P. falciparum
Malarone
Prophylaxis: Areas with chloroquine-resistant P. falciparum
Mefloquine
Prophylaxis: Areas with multidrug-resistant P. falciparum
Doxycycline
Prophylaxis: Terminal prophylaxis of P. vivax and P. ovale infections; Alternative for primary prevention
Primaquine
Tissue protozoan; Definitive host: domestic host; humans and other mammals are intermediate hosts; ingestion of cysts in raw meat, contaminated food, transplacentally; fecal oocyts; 2 types of trophozoites: tachyzoites and bradyzoites
Toxoplasma gondii
Immunocompetent; immunocompromised; Encephalitis: ring-enhancing lesions; congenital toxoplasmosis: intracranial calcifications
Toxoplasmosis
Treatment of Toxoplasmosis
Sulfadiazine plus pyrimethamine
Blood and tissue protozoan; 4 forms: amastigote, promastigote, epimastigote, trypomastigote; transmitted by reduviid bug; trypomastigotes in blood
Trypanosoma cruzi
Allowing an uninfected, laboratory-raised reduviid bug to feed on the patient
Xenodiagnosis
Periorbital edema (Romana’s sign); Nodule near bite (chagoma); Fever, LAD, and hepatosplenomegaly
Acute Chagas’ Disease
Myocarditis, megacolon, megaesophagus, achalasia
Chronic Disease (Trypanosoma cruzi)
Treatment of Chagas’
Nifurtimox
Blood and tissue protozoan; Only 2 forms: Epimastigote, Trypomastigote; remarkable antigenic variation; Transmission: tsetse fly
Trypanosoma brucei
Indurated skin ulcer
Trypanosomal chancre
Enlargement of the posterior cervical LN
Winterbottom’s Sign
Hyperesthesia
Kerandel’s sign
Plasma cells with cytoplasmic immunoglobulin globules
Mott cells
Treatment of Sleeping sickness
Suramin for blood-borne diseaseMelarsoprol for CNS penetration