chapter 20 Microbial diseases of the Gastro Intestinal System

what are the 4 normal host defenses for GI tract

1. stomach acid (ph-2)

2. Musus

3. Peyers patche in the small intestine

4. Normal microbiota

normal microbiota in teh GI tract are tuypically which type of aerobe/anaerobe

obligate and facultative ANArobes

how do GI diseases even work. What must the pathogen do

must attach to the wall of GI tract or they will be put into waste

AND it must also overcome the acidity of the stomach

what is this.

Acid producing bacteria slowly destroy tooth enamel and allow infection of interior of tooth

dental carries/cavaties

this bacteria forms a sticky capsule on surface of tooth

• other bacteria join in to make PLAQUE

s.mutans

what three symptoms result from bacterial diseases of the lower digestive system

1. diarrhea

2. gastroenteritis

3. dysentery

which bacteria is being described

• enterotoxin is considered to be heat resistant

• symptoms include nausea, vomitting, diarrhea

staph. Aureus

what bacteria is being described

• CLIINICAL FEATURES: lose, nonbloody stools. abdominal cramping, chills, headache

• TREATMENT: oral rehydration

salmonellosis

what bacteria is this

• infection from contaminated foods (eggs, meat)

salmonellisos

typhoid fever is caused by what

salmonella typhi

typhoid fever:

• bacteria is spread throughout the body in __________

phagocytes

entero-hemorrhagic strains such as E.coli produce a shiga toxin. O___,H___

O157

H7

in the shiga toxin from e.coli, the O is the ______ and the H is the _____

O: call wall antigen

H: flagellar antigen

H.pylori causes…

stomach & duodenal ulcers

H.pylori is now also a known cause of _______

stomach cancer

C. difficile is part of the normal microbiome; can over grow when flora are disrupted by ____

innapropriate use of antibiotics

transmission of C.difficile includes…

fecal-oral

treatment for C.difficile includes

removal of antibacterial antibiotics (metronidazole)

what are the three viral diseases of the digestive system

1. mumps

2. Viral gastroenteritis

3. Hepatitis

mumps enters through the _____

respiratory tract(saliva and other secretions)

what are the two causative agents in viral gastroenteritis

ROTAVIRUS

NOROVIRUS

This is a causative agent of viral gastroenteritis

• causes comitting and diarrhea for 1 week

• Most common in children

rotavirus

this is a causitive agent of viral gastroenteritis

• causes vommiting and diarrhea for 2-3 days

norovirus

this GI viral diseases causes inflammation of the liver

hepatitis

describe the vaccine in Hep.B

genetically modified vaccine produced in yeast

describe vaccine in Hep. D

HBV vaccine is protective

hep.B can be transmitted through _________

blood transfusions

what are reservoirs for protozoan diseases of the GI system

animal and human feces

protozoans often produce ____-______ cysts as a part of their life cycle. Once in inestine, these cysts produce _________ that attack _______ _______

acid-resistant

trophozoites

intestinal mucous

this protozoan disease…

• transmitted through contaminated water

• attaches to intestinal wall leading to diarrhea, abdominal cramping, bloating

• treated with metronidazole

Giardiasis

Giardia lambia

this protozoan disease

• ingestion of contaminated water with oocysts

• Oocysts release sporozoites into intestine

cryptosporidiosis

Cryptosporidiosis is caused by ingestion of contaminated water containing _______. These ________ release ________ into intestine. These ______ are resistant to ________ and must be filtered out

oocysts

oocysts
sporozoites

oocysts
chlorine/chloronation

this is the bacteria causing tapeworms

taenia solium and Taenia saginata

whata re the 4 nematodes

1. pinworms

2. hookworms

3. ascariasis

4. trinchellosis

pinworms are caused by this bacteria

enterobius vermicularis

the definitive host of pinworms is:

humans

this is a common symptom of pinworms

itching anus at night

treatment of pinworms is…

mebendazole

which nematode is this…

• larvae in soil hatched from eggs sged in feces

hookworms

this nematode…

• lives in human intestines

ascariasis

ascarisis lumbridoides

which nematode is this…

• larvae encyst in muscles of humans and other mammals

• transmitted by ingesting larvae in undercooked meat (typically pork)

• ASYMPTOMATIC

Trichinella spiralis, trichinellosis

WILL BE ON EXAM»>

• loss of apetite, weight loss, irritibality, and anal itching

• light microscope of adult works removed on cellophane tape

• Abendazole

enterobiasis (PINWORM)