Disease Detectives B/C

[Eggo]

The change in risk of a given activity or treatment in relation to a control activity or treatment.
Although I just cut and pasted this, I really learned a lot by reading about this. Thanks Bernard!

[bernard]

The change in risk of a given activity or treatment in relation to a control activity or treatment.
Although I just cut and pasted this, I really learned a lot by reading about this. Thanks Bernard!

Correct! Another way to define it is: risk difference is the difference in rates of occurrence between exposed and unexposed groups in the population.

[Eggo]

Okay, what is herd immunity?

[mkb14954]

Herd immunity is a form of immunity in which the majority of the population is immunized so that those who have not developed immunity can stay protected.

[Eggo]

Correct! Your turn!

[mkb14954]

Here's an easy one.

Name three types of descriptive studies.

[bernard]

Here's an easy one.

Name three types of descriptive studies.

Answer (Click to Show Hidden Text)

[b]Descriptive studies[/b], which generate hypotheses, include case report, case series, incidence, cross-sectional, and ecologic studies. Here are two helpful links for those interested in reading more: [url=http://www.cdc.gov/globalhealth/fetp/training_modules/19/desc-and-analytic-studies_ppt_final_09252013.pdf]1[/url] and [url=http://samples.jbpub.com/9780763754433/Chapter4.pdf]2[/url].

[mkb14954]

Great Answer! Your turn.

[bernard]

Here's a longer question that matches the types I've seen at tournaments:

On September 7, 1997, a brief report in the press described a problem of disease among fish and illness among watermen (commercial fishermen) working along the Eastern Shore of the Chesapeake Bay. The report cited the case of an experienced fisherman who after two days working on the Potomac River was ill with nausea, vomiting, and stomach cramps. Other workers reported small, itchy, red, circular skin rashes, memory loss, and respiratory tract problems. Fish, reported to have bloody sores, died by the thousands. The fisherman mentioned above said he found sores on as much as 90% of his catch. Maryland officials say that because of publicity, the loss in retail fish sales could be as high as $20 million.

Some scientists attributed the human symptoms to contact with toxin released by a microorganism called Pfiesteria piscicida, which was first identified in the early 1990s, but is thought to have existed for centuries. Some researchers believe this one-celled organism normally exists in a non-toxic form and that animal waste and fertilizers from farms discharged into waterways helped the Pfiesteria to multiply. Concerns about the problem caused the states of Maryland and Virginia to prohibit activities such as swimming, boating, and fishing in a seven-mile stretch of the affected area. In North Carolina, where problems linked to Pfiesteria have recurred for years, officials planned to carry out studies similar to those in Maryland.

Develop and specify probable hypotheses to explain the cause, source, and spread of the outbreak.

[dragons790]

How's this? (Click to Show Hidden Text)

Cause: The amount of Pfiesteria piscicida increased, causing a higher, more dangerous amount of toxin to be released, causing the symptoms.
Source: Excess nutrients from animal waste and fertilizers caused Pfiesteria piscicida to multiply.
Spread: The outbreak was limited to waterways with high populations of Pfiesteria piscicida, such as the eastern shore of Chesapeake Bay and North Carolina.
.