For the third year running, the sexually transmitted infection chlamydia is the top reported disease in Salt Lake County, a new report shows.

Gonorrhea, which is also sexually transmitted, was second, followed by hepatitis C, influenza and tuberculosis, according to the Salt Lake County Health Department report, which ranks the top 20 most catalogued diseases and infections reported across Utah’s most populated county.

Published as part of the health department’s annual Infectious Diseases Morbidity Report 2016, the rankings are part of a full 2016 report available online, along with a weekly tracking numbers on infectious diseases and a monthly update on pertussis, also known as whooping cough.

“These reports are a resource for health care providers, public health practitioners, community partners and the public at large,” Dagmar Vitek, medical director for the county health department, said in a statement. “We must all work together to help control the spread of disease.”

State law requires health care providers to report the diagnosis or identification of more than 80 infectious diseases for ongoing surveillance and investigation. County epidemiology and infectious disease bureaus compile the data from labs, hospitals, outpatient clinics and medical providers and also conduct patient interviews and chart reviews for the annual report.

Top 10 reported diseases in Salt Lake County for 2016 were:

  • Chlamydia
  • Gonorrhea
  • Hepatitis C (both acute and chronic)
  • Influenza (hospitalized cases)
  • Tuberculosis
  • Hepatitis B (acute and chronic)
  • Campylobacteriosis
  • Pertussis
  • Streptococcal disease  (invasive, group A)
  • Salmonellosis

In 2016, health department officials investigated more than 14,000 reports of disease across the county.

The instances of diseases reported is likely lower than the number of actual cases across Salt Lake County. And even a few cases of some diseases can be a cause for concern, officials said.

Syphilis, despite being ranked 13th in 2016, saw 106 reported cases, which represented a significant increase from the prior year, a spike that could be the “beginning of a syphilis outbreak,” said Lynn Beltran, epidemiology supervisor and STD prevention manager.

“This is a big reminder that everyone who is sexually active should be tested for STDs,” Vitek said.