Parasites Flashcards
What group of unicellular organisms has been the cause of more disease and death than any other group historically?
Protozoa (malaria, african sleeping sickness)
What is giardiasis?
caused by Giardia lamblia, a flagellate. Infects duodenum and jejunum of humans by ingestion of fecally contaminated water or food containing giardia cysts.
What is the pathophysiology of giardiasis?
Parasites attached to the bowel wall cause irritation and low-grade inflammation of the duodenal or jejunal mucosa. As the parasites pass into the colon, they typically encyst. Cysts are found in the stool in enormous numbers.
What are the symptoms of giardiasis?
diarrhea, malaise, steatorrhea, abdominal cramps, bloating, flatulence, nausea, weight loss, and vomiting. chronic infection leads to major weight loss, malabsorption, and depression. Stools are watery, greasy, foul-smelling.
How is giardiasis diagnosed?
STOOL Sample-fecal smear or ELISA to look for distinctive cysts. Examination of the duodenal contents as cyst production may be sporadic and not found in smear examination
What is the treatment for giardiasis?
Metronidazole (Flagyl) 250mg twice daily for 5 days. Oral quinacrine hydrochloride (Atabrine) and furazolidone (Furoxone) are alternatives
What is amoebiasis?
caused by Entamoeba histolytica or Dientamoeba fragilis in the large intestines. mostly a disease of travelers.
What is the pathophysiology of amoebiasis?
The cyst is ingested. The trophozoite emerges from the ingested cyst in the stomach and duodenum. Divides then passes to the cecum and produces a population of lumen-dwelling trophozoites. Trophozoites invade intestinal epithelium causing ulcers
What are possible complications of amoebiasis?
may undermine large areas of the mucosal surface. perforation into the peritoneal cavity. Secondary bacterial invasion, and accumulation of neutrophilic leukocytes. amoebic hepatitis or liver abscess
What are the symptoms of amoebiasis?
abdominal tenderness, Fulminating dysentery and dehydration. less acute: Episodic diarrhea, n/v, and urgent desire to defecate. weeks of cramps, loss of appetite, weight loss and malaise
How is amoebiasis diagnosed?
Stool Specimens or enzyme immnoassay
What is the treatment for amoebiasis?
Asymptomatic: Paromomycin and diloxanide furoate 500 mg tid x 10 days. Symptomatic: Metronidazole 750 mg tid for 5-10 days followed by diloxanide
What are the four species of plasmodium responsible for human malaria?
Plasmodium vivax, Plasmodium malariae, Plasmodium ovale, Plasmodium falciparum (very lethal)
What are the symptoms of malaria?
Chills, Night sweats, Fever, Headache, Muscle pain, Cough and chest pain, Splenomegaly, hepatomegaly
What is congenital malaria?
should be considered in febrile newborns/infants who could have been infected by mother. can occur if the mother became infected during her pregnancy or from an infection acquired months or years before.
What is prophylaxis for malaria?
Chloroquine phosphate 500 mg weekly, continue 6 weeks after leaving area (add Fansidar in area w/cholorquine resistance). Or Primiquine phosphate 26.3 mg daily, start 1-2 days before travel and continue 7 days after leaving area
What is treatment options for malaria?
Chloroquine (most strains of Plasmodium show resistance). Atovaquone & proguanil (Malarone). Hydroxychloroquine(Plaquenil). Doxycycline. Mefloquine(Larium)
What is cryptosporidiosis?
caused by protozoan parasite Cryptosporidium hominis. one of the most common causes of water bourne illness in US
What is the pathogenesis of cryptosporidiosis?
found under the outer membrane of the cells lining the stomach or intestine. Oocysts, passed into feces are the infective agents.
What are the symptoms of cryptosporidium?
Stomach cramps, watery diarrhea, dehydration, weight loss, vomiting, fever, severe malabsorption, electrolyte imbalance
What is toxoplasmosis?
caused by a coccidian protozoa toxoplasma gondii. Hosts are cat species. Many ppl infected but very few immunocompetent patients have symptoms
What is the pathogenesis of toxoplasmosis?
Oocysts develop in the cat GI tract, and pass out via the feces. the oocyst opens in the human’s duodenum and releases the sporozoites that pass through the gut wall, and invade macrophages. They penetrate nerve cells, where they multiply to form tissue cysts, initiating the chronic stage of disease.
What are symptoms of toxoplasmosis in an immune compromised patient?
hepatitis, pneumonia, blindness, and severe neurological disorders
What are symptoms of toxoplasmosis in an immunocompetent patient?
Body aches, Swollen lymph nodes, Headache, Fever, Fatigue, Occasionally, a sore throat