Parasit Flashcards

Question

Entamoeba histolytica Life Cycle

Answer 1

- excystation in small intestine > release trophozoites > migrate to large intestine - multiply > binary fission > produce cysts (encystation) -both stages are passed in the faeces

Answer 2

- found in soil; fresh, brackish, and sea water; sewage... - replicate by mitosis (trophozoites are infective stage) - believed to enter the body through lower respiratory tract, ulcerated skin and invade CNS -cysts and trophozoites are found in tissue

Answer 3

- has three stages, cysts, trophozoites, & flagellated forms - the trophozoites replicate by promitosis - found in fresh water, soil... - Trophozoites infect humans by entering olfactory neuroepithelium & reaching the brain! where inflammation occurs = death

Answer 4

Human- Schizogony 1. exoerythrocytic schizogony -parasites undergoes asexual multiplication in the liver -inside hepatocyte, sporozoite develops into trophozoite -after 1-2 weeks, trophozoite nucleus divides, followed by division of the cytoplasm -thousands of merozoites produced!rupture from cell!enter blood circulation! invade red blood cells 2. erythrocytic schizogony -inside erythrocyte, the merozoite grows to the early trophozoite stage- the signet ring stage -this form develops into the mature trophozoite stage!undergoes multiple fission into schizonts!produces a new generation of merozoites in each erythrocyte (gametocytes) Mosquito- Sporogony -mosquitos ingest gameotocytes during blood meal!undergo a sporogonic cycle yielding sporozoites - in p.vivax and p.ovale, a dormant stage (hypnozoites) can persist in the liver!causes relapses weeks/ years later

Answer 5

-oocysts are only present in the definitive host!passed in faeces!ingested by humans and other intermediate hosts -oocysts develop into tachyzoites (rapidly multiplying trophozoite form of t.gondii) -they divide rapidly in cells, causing tissue destruction and spreading the infection -tachyzoites localize to muscle tissues and the CNS where they convert to tissue cysts, or bradyzoites !animal-to-human (zoonotic) transmission !foodbourne transmission !mother-to-child (congenital) transmission

Answer 6

- c.parvum and c.hominis occur in humans -cryptosporidium is found in soil, food, water, or surfaces that have been contaminated with infected human or animal faeces - a person becomes infected by swallowing cryptosporidium parasites - cryptosporidium lives in the intestine of infected humans or animals transmission: -person to person -animal to human -foodbourne -waterbourne - has three stages, cysts, trophozoites, & flagellated forms - the trophozoites replicate by promitosis - found in fresh water, soil... - Trophozoites infect humans by entering olfactory neuroepithelium & reaching the brain! where inflammation occurs = death

Answer 7

Incubation Period: 7-30 days Shorter periods!p.falciparum Longer periods!p.malariae Most frequent symptoms: -fever and chills, sweats -headache -myalgias, arthralgias -weakness -nausea and vomiting -splenomegaly -anemia, thrombocytopenia “Cold” Stage: 15-60min, cold, shivering “Hot” Stage: 2-6hrs, fever, headaches, vomiting “Sweating” Stage: 2-4hrs, sweats, temp to normal P.falciparum: -infections caused by seveer, potentially fatal forms: -CNS involvement (cerebral malaria) -acute renal failure -severe anemia -respiratory distress syndrome -hemoglobinuria cerebral malaria -parasitized RBCs in brain vessels -freq. leads to death -microvascular obstruction by thrombus formation -disseminated coagulation -coma!poor oxygen delivery to brain

Answer 8

- microscopic identification of gametocytes, merozoites, schizonts - comparison of plasmodium species - molecular diagnosis techniques can complement microscopy, especially in species identification ! PCR - people with sickle cell anemia cannot get malaria, therefore frequencies of sickle cell carriers are high in malaria-endemic areas - no vaccine against malaria is available

Answer 9

-acquired infection is generally asymptomatic -10%-20% of patients with acute infection may: -develop cervical lymphadenopathy -and/or a flu-like illness -the clinical course is benign and self-limited -symptoms usually resolve within a few months to a year Acute -parasitic invasion of the mesenteric lymph nodes & liver -painful, swollen, lymph glands in the inguinal, cervical, and subclavicular regions -fever, headache, anemia, muscle pain Congenital -results from fetal transplacental infection -12% of infected infants born alive die shortly after birth -abnormalities occur in the CNS, eyes, and viscera

Answer 10

- serologic testing!antibody detection - observation of parasites in patient specimens, such as bronchoalveolar lavage material or lymph node biopsy -detection of parasite genetic material by PCR, especially in detecting congenital infections in utero

Answer 11

Cryptosporidiosis -some people will have no symptoms at all -most common symptom is watery diarrhea Other symptoms: -stomach cramps or pain -dehydration -nausea -vomiting -fever -weight loss

Answer 12

- microscopic diagnosis- oocysts in the stool -ELISA- antigen in the stool -immunofluorescence assay - molecular methods

Parasit Flashcards

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