Built on an invented banquet outbreak, the PU520 Unit 5 investigation example defines a case, draws the epidemic curve, calculates food-specific attack rates and names the most likely vehicle. Searches like "pu 520 unit 5 assignment example", "pu520 unit 5 sample" and "pu520 unit 5 example" land here.
What a finished PU520 Unit 5 outbreak investigation looks like
Written as a short investigation report, the example follows a health department's usual sequence. It opens with the notification, a call from the banquet organizer two days after the event. A case definition follows in a boxed paragraph, tiered as confirmed and probable. The epidemic curve comes next, a histogram of onset times in eight-hour bins with the meal marked on the horizontal axis, showing a rise beginning about 16 hours after dinner and a peak in the 32-to-40-hour interval. A food-specific attack rate table lists eleven menu items, with ill and well counts among eaters and non-eaters. The green salad stands out: 48 of 70 who ate it became ill, against 14 of 70 who did not, a risk ratio of 3.4. Control measures and a limitations paragraph close the report.
How a PU520 Unit 5 example is structured
The report follows the logic of the investigation steps rather than the order in which facts were discovered. Verification and the case definition come before any count, because an outbreak without a definition cannot be counted at all, and the clinical criteria decide who enters the curve. The curve precedes the food table since its shape sets the hypothesis. A single peak with a spread matching norovirus incubation points to one exposure at one meal, which justifies analyzing that meal's menu instead of searching wider. The attack rate table then tests the hypothesis item by item. The salad's ratio is interpreted alongside the kitchen interview, which found a food handler who had been sick the day before. A small second bump on the curve, four days out, is identified as household spread and kept separate from the point-source cases.
The case definition box
Clinical criteria of vomiting or three loose stools in 24 hours, restricted to attendees and staff, with onset within 72 hours of the dinner. Stool testing distinguishes laboratory-confirmed cases from probable ones.
An epidemic curve anyone can read
Eight-hour bins, labeled axes, the meal time marked with an arrow, and case counts on the vertical axis. The caption states the shape in words: a point-source pattern followed by one late cluster.
Attack rates by menu item
Eleven rows, ill and well among eaters and non-eaters, with attack rates and a ratio for each. Items with ratios near 1.0 stay in the table, since ruling foods out is part of the evidence.
The kitchen interview
A food handler reported vomiting the evening before the event and returned to prepare cold dishes. The report treats this as supporting evidence rather than proof, and notes that no leftover salad remained for testing.
Secondary cases held apart
Five illnesses among household members of attendees appear after day three. They meet the clinical criteria but not the exposure criterion, so they are counted separately and described as person-to-person spread.
Control measures and limits
Exclusion of ill food workers until 48 hours after symptoms end, cleaning with a disinfectant effective against norovirus, and a note that food histories recalled two days later are imperfect.
Where marks go in PU520 Unit 5
Outbreak rubrics in many sections reward the case definition, the curve, the analysis and the public health action as separate criteria. The example scores the definition row by including person, place and time, plus clinical criteria concrete enough that two investigators would classify the same guest the same way. Curve marks depend on readable axes, sensible bins and an interpretation of shape; a histogram with daily bins would flatten a norovirus outbreak into two or three bars. Analysis marks go to attack rates computed for eaters and non-eaters of every item, not only the suspect food. Deductions commonly come from a definition missing its time window, a curve drawn as a line of cumulative cases, a vehicle named on attack rate alone without supporting evidence, and control measures that never mention the ill worker.
Get a PU520 Unit 5 example written to your instructions
Forward the outbreak scenario your PU520 Unit 5 assignment provides, including any line list or food history table, plus the directions and rubric. A case definition, a curve binned to suit the suspected pathogen, and attack rates for every listed exposure come back in the free first custom sample within 24-48 hours.
PU520 Unit 5 questions, answered
How should the curve's time intervals be chosen?
A common rule of thumb sets the bin width at roughly a quarter to a third of the suspected agent's average incubation period. Norovirus averages around 33 hours, so eight-hour bins show the rise and fall clearly. An agent with an incubation near fourteen days needs daily bins instead. The example prints its bin width under the chart, beside the incubation figure it was derived from.
What if no food item has a clearly higher attack rate?
Then the report says so and widens the hypothesis. A flat table can point to a contaminated item missing from the menu list, such as ice or water, to person-to-person spread from an ill attendee, or to an exposure outside the event entirely. The epidemic curve helps decide among these, since propagated spread produces successive peaks instead of one.
Does the investigation need laboratory results?
It needs to say what testing was done or would be needed. Many classroom scenarios include a few confirmed specimens, and the case definition then separates confirmed from probable cases. The banquet example has stool results for six guests, all positive for norovirus, which supports the clinical picture without being required for every counted case.