By law, certain health conditions must be reported to the State of Iowa upon diagnosis. Examples are Tuberculosis, Hepatitis A, Chlamydia, Rabies, Lead Poisoning and over 40 more.
One of the functions of a local health department is following up the diagnoses. Follow up could include phone interviews with potentially exposed individuals, collecting samples for lab testing, and referral to appropriate treatment.
A key to halting the spread of an infectious disease is identifying and testing everyone who may have been exposed. Dallas County Health Department is supported in these efforts by the Center of Acute Disease Epidemiology (CADE). CADE is a bureau within the Iowa Department of Public Health, tasked with protecting us from infectious disease. See http://idph.iowa.gov/cade.
We are exposed to negative health situations through different means of transmission. Using the examples above, note that Tuberculosis is airborne, Hepatitis A spreads via stool, Chlamydia through sexual contact, Rabies from animal bites, and Lead Poisoning through environmental exposure. Public health officials respond to reports with informed, real time decisions. They may quarantine, remove infected people from a food-preparation job, or remove children from a building with lead-based paint. The practice of timely and accurate reporting protects all of us.