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Chapter 23 Lecture 4 (Cryptosporidiosis (Diagnosis, treatment, and…
Chapter 23 Lecture 4
Cryptosporidiosis
Signs and symptoms
Severe watery diarrhea with potentially serious complications
HA, muscular pain, cramping, nausea, fatigue, and severe fluid and weight loss, accompanied by diarrhea all leads to life threatening malabsorption, hepatitis, & pancreatitis
Pathogen and pathogenesis
Caused by Cryptosporidium parvum which is an intracellular parasite that is banana shaped Pathogenicity of C. parvum is unclear
Epidemiology
Infection results from drinking contaminated water
Diagnosis, treatment, and prevention
Presence of oocysts in feces is diagnostic
Treated with fluid and electrolyte replacement
Prevented with proper hygiene
Amebiasis
Signs and symptoms- depend on the health of the host and the virulence of the infecting strain. (3 types)
Luminal amebiasis is asymptomatic and occurs in healthy people
Invasive amebic dysentery causes severe diarrhea, colitis, and appendicitis , bloody mucus containing stools and pain
Invasive extraintestinal amebiasis causes potentially fatal necrotic lesions in various organs like the liver, lungs, spleen, kidneys, or brain
Pathogen, virulence factors, and pathogenesis
Caused by Entamoeba histolytica all three forms
Virulent strains produce numerous proteins that are toxic to cells and facilitate invasion
Trophozoites in the lumen of the intestine do little damage and typically make no symptoms, but when they invade the the peritoneal cavity or blood cause symptoms of invasive extraintestinal amebiasis
Epidemiology
Transmitted by consumption of contaminated food or water, from contaminated hands, or by oral-anal intercourse
Cockroaches and houseflies can help spread cysts under conations of overcrowding
Travelers, immigrants, institutionalized populations and male homosexuals are at greatest risk estimated 500 million people worldwide 90% develop Luminal amebiasis
Majority of individuals develop luminal amebiasis
Human carriers help maintain transmission
Diagnosis, treatment, and prevention
Diagnosed by microscopic observation of Entamoeba in stool or intestinal biopsy
Treated with oral rehydration therapy and antiamebic drugs
Prevent with proper hygiene and safe sex practices
Individuals in endemic areas should drink bottled water and avoid uncooked vegetables or unpeeled fruits
Protozoan Diseases of the Intestinal Tract
Giardiasis
One of the more common waterborne GI diseases in the US
A host will swallow a cyst from contaminated food or water, or even hands
The cyst will survive the stomach acid & releases a trophozoite in the sm. Intestine and then they multiply
Trophozoites attach to the lining in the intestine they can cover the intestinal surface which decrease absorption and you get a large quantity of undigested food.
Intestinal wall gets scarred from the adhesive disk attachment is uses
Trophozoites pass into the colon, encystment occurs they form into a cysts
Both trophozoites and cysts are expelled in the host feces, but only the cysts will survive outside the host
Signs and symptoms
Often asymptomatic but can cause some GI distress
Diarrhea and associated symptoms can last up to four weeks
Severe, greasy, frothy fatty diarrhea, pain, flatus, N/V, stools have rotten egg smell this is a notable symptom of giardiasis
Pathogen
Caused by Giardia intestinalis a flagellated diplomonad
2 forms: motile feeding trophozoite, and a dormant cyst
G. intestinalis cysts are resistant to chlorine, heat, drying, and stomach acid
Epidemiology
Occurs in developed and developing countries
Individuals ingest cysts from contaminated water, food, or hands
Hikers, campers, and swimmers are at particular risk
Diagnosis, treatment, and prevention
Diagnosed by microscopic observation of Giardia in stool
Treated with tinidazole (not yet approved in US) or metronidazole (U.S.)
Oral rehydration therapy may be needed
Prevention relies on using good hygiene and filtering water in endemic areas. Washing hands when dealing with disposable diapers especially in day care centers