Afebrile Diarrhea caused by Fungus Flashcards
Charcteristics of Microsporidia
Fungus, obligate intracellular, spore
Infectious state of Microsporidia
spore
Spore Characteristics of Microsporidia
Coiled polar tubule “belt” for extrusion of spore contents into host cell
Most common cause of chronic diarrhea/gastritis in patients with HIV?
Microsporidia/Enterocytozoan bieneusi
___% of AIDS pts have Microsporidia develop chronic diarrhea
50
Other risk factors for Microsporidia
traveler’s, children, organ transplant recipients, and elderly
Transmission of Microsporidia is primarily
Direct human contact
In an immunocompetent person, Microsporidia infection
rarely causes symptoms
Symptoms of Microsporidia infection
Diarrhea, acalculous cholecystitis (fever and right upper quadrant tenderness)
Host immunity to Microsporidia
T cells
Diagnostic tests for Microsporidia
O&P w/ concentration + trichrome stain; polar coiled tubules are diagnostic
Treatment for Microsporidia
Albendazole
Characteristics of Cyclospora
Fungus, mildly Acid-fast (+), intracellular organism
Risk Factors for Cyclospora
Asia and South America, contaminated water and imported fruit (raspberries, strawberries, cilantro), warm and rainy, AIDS
Symptoms of Cyclospora
Watery diarrhea, fatigue, anorexia, weight loss, and upper intestinal pain
Duration of Cyclospora symptoms
~20-38 days
Transmission of Cyclospora
NOT direct contact; oocyst must sporulate in environment
Incubation period for Cyclospora
1 week
Characteristics of Cyclospora oocyst
large, mildly acid-fast, auto fluoresce
Life cycle of Cyclospora
Oocyst is passed, sporulation occurs days to weeks later in the environment at 22-32 °C. Sporont divides into 2 sporocysts, each containing 2 elongated sporozoites
Ingestion of the sporulated oocyst occurs and the oocyst excyst in the GIT, freeing the sporozoites which invade epithelial cells of the sm. intestine. Inside cells they undergo asexual multiplication and sexual development to mature into oocysts.
Diagnosis of Cyclospora infection
presence of large autofluorescing, mildly acid-fast oocysts in stools
Treatment of Cyclospora infection
TMX-SMZ
TMX-SMZ MOA
acts as a substrate inhibitor of dihydropteroate synthetase. Sulfonamides are analogs of p-aminobenzoic acid (PABA) and are competitive inhibitors of the enzyme, inhibiting the production of dihydropteroic acid. Trimethoprim acts by interfering with the action of bacterial dihydrofolate reductase, inhibiting the synthesis of tetrahydrofolic acid
