Question

The case of the nauseating lunch. Part 3.

About 300 of the school's 900 students reported a gastrointestinal disease over a three-day period. Statistical analysis of positive samples found that those who ate at the college salad bar were six times more likely to fall ill than others. Customers of the adjacent wraps restaurant were three times more likely to fall ill. Even people who ate food prepared elsewhere, but sat near the two restaurants, were found to be twice as likely to get sick as those who ate and sat elsewhere. The investigation identified one person who worked at both the salad bar and wraps station during the outbreak. The worker reported not changing gloves when switching between the two restaurants. Although not strictly a violation of food safety rules, this did provide a possible link between the clusters of cases at the two restaurants. Tests on several lettuce heads from the salad bar came back positive for norovirus. Patrons of other school restaurants that used the same lettuce vendor also reported some norovirus cases. The health department contacted the lettuce company, which issued a voluntary recall for products shipped that week. The company never found the infection source in the packing plant. But after performing a thorough decontamination of the facility, no further cases were traced to the company's lettuce, and the outbreak ended.

How could you tell if these infections came from the same source? (NCLEX-HESI-TEAS Style)

Perform protein analyses and compare amino acid sequences.

See what cells the viruses infect. If they infect the same cell type, they are from the same source.

Perform genetic analyses and compare RNA sequences.

All of the above

Answer 1

Perform genetic analyses and compare RNA sequences.

Viruses contain DNA or RNA sequences which can be detected by various techniques like PCR and sequencing of the genome.