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Infectious Diseases Chapter 11

How transmission to human occurs by the following nematodes:
filaria worms
hookworms- contact
Trichinella- pork consumption
filaria worms- mosquitos
Enterobius- Contact
Giardia is a water borne protozoan parasite. It causes diarrhea, dehydration, cramping. The virulence is 10 cysts for disease to occur, and their suction discs damage the intestinal epithelial lining. It is common is child care centers, municipal facilities because chlorine does not kill it. Reservoirs are humans, raccoons, beavers, dogs, cattle. Treatment is albendazole or metronidazole.
Amoeba sarcodina
Entamoeba histolytica causes ulcers in the intestines. The disease has an incubation time of 1 to 3 weeks so travel history is very important to observe.
What are the three stages of T. cruzi and where are they found?
amastigote (intracellularly), epimastigote (inside the vector), and typomastigote (inside the blood of the host).
Acute vs Chronic infection of T. cruzi
Acute infection involves localized inflammation around an opening of the face (eye, nose, mouth) and it does disappear. Chronic infection occurs 20 to 30 years later and causes an enlarged heart and intestines leading to death.
How would you implement control measures for Chaga's disease?
To control this disease I would improve the living conditions of the area because how they are now is a perfect breeding ground for the organism and the kissing bug. However, if that is not possible especially because of limited funding, I would spread pesticides around the area because that kills off a majority of the organisms.
Why are hookworms associated with poverty?
Because they are found in soil, so in areas where shoes are not available, the organism is much more prevalent
schistosome life cycle
Eggs in feces -> Water to mature -> becomes micracidium -> immediate host fresh water snail -> becomes cercaria -> pierces human skin -> eggs in feces
The are the two stages of Giardia?
It has two stages- trophozoite and cyst. Cyst form is the transmission stage.
How do you diagnose Entamoeba Histolytica? How does it work?
ELISA- The bottom of each well is coated with a protein to which will bind the antibody you want to measure. The serum is incubated in a well, and each well contains a different serum. After some time, the serum is removed. To detect the bound antibodies, a secondary antibody is added to each well. The secondary antibody would bind to all human antibodies (anti human from donkey). Attached to the secondary antibody is an enzyme such as peroxidase or alkaline phosphatase. These enzymes can metabolize colorless substrates into colored products. if it changes color the antibody is present
How do you detect pinworms?
scotch tape
Why do hookworms increase the number of eosinophils?
Eosinophils are present during allergic and worm infections so they are a good determination if one of those are present.
How is trichinella transmitted and what does it do?
acquired by eating undercooked meat and forms cysts in smooth muscle.
Name three factors that affected the 2000 E. coli outbreak in Ontario
Monitorying the water supply was deficient.
Factory farmi allows a lot more cows to be handled, leading to a large amount of waste to be dealt with. that waste was used as fertilizer for vegetables.The cattle in this environment are put under lots of stress, increasing their risk of infection, and the close proximity to other cattle increases the chances of an organism being transmitted.
City PUC reduced levels of Chlorine in the water because people were complaining of the taste. However, those low levels of chlorine made it easier for E. coli to survive.
Their lab was not government certified, and not accredited to test bacteria.
Marlene Geither's presentation on Norovirus
Norovirus Outbreaks in 2010 on the Colorado River through the Grand Canyon: 63 people became ill. May through June 2010. Symptoms: vomiting and diarrhea lasting 1 to 2 days.
Norovirus is ssRNA virus that cannot be cultured. Only host is humans, infectious dose is about 10 particles. No treatment or vaccine for norovirus
Transmission is fecal/oral (food, water, person to person, fomites)
Dr. Price on Antibiotics
Most animals in the US are fed antibiotics, and raised in CAFO's increasing the risk for disease. The overuse of antibiotics has allowed the organisms that affect them to become resistant to those antibiotics. Those Antibiotic Resistant organisms are in the animals and their feces, which is used to fertilize the vegetables that we eat. Concern is eventually we will not have antibiotics to fight these infections
Jeff Foster- white nose disease in bats
Pathogen- Geomyces destructans. The infection disturbs the bats hibernation, making them use energy that they needed to get through the winter months. Bats consume insects (mosquitos) and agricultural pests that help to maintain human health. Less bats leads to more of these pests which cost money to get rid of. No infectious disease to known to purely cause the extinction of a species. approach is to look at the TLR's of those bats that did survive.