SALT LAKE CITY — The most common infectious diseases in the county continue to be sexually transmitted diseases, according to a new health department report.

"Sexually transmitted diseases continue to be our most frequently reported diseases in the county," said Dr. Dagmar Vitek, Salt Lake County Health Department medical director. "Besides chlamydia and gonorrhea at the top of the list, syphilis and new HIV infections also make the top 20."

The top five most commonly reported diseases in Salt Lake County in 2017 include chlamydia, gonorrhea, hepatitis C, influenza and tuberculosis, the report states.

Cryptosporidiosis and shigellosis dropped off the list of the top 20 conditions, compared to 2016 results from the Salt Lake County Health Department. Hepatitis A and viral and aseptic meningitis became more prevalent, though, joining the list in 2017.

The health department cautions that the number of conditions circulating the community could be higher, as not all instances of disease are reported to the health department — even though Utah law requires it whenever one of more than 80 infectious diseases are diagnosed or identified at labs, hospitals, doctor offices and clinics statewide.

"We must all work together to help control the spread of disease," Vitek said. "And, for the public, that primarily means getting tested."

More than 5,300 cases of chlamydia were reported last year, with the majority of them between the ages of 15 and 24; and, there were 1,672 reported cases of gonorrhea, on the rise since 2010, the Infectious Disease Morbidity Report states. Both highly infectious, sexually transmitted diseases have surpassed the national average in Salt Lake County.

Cases of syphilis, another sexually transmitted infection, are also increasing over the years, with the 144 reported in 2017 being the highest ever recorded, according to the report. Thirty-five percent of those were also infected with HIV.

Six hundred and ninety-five people were hospitalized for influenza and there were 571 cases of latent, asymptomatic tuberculosis, which is typically found when people are tested for work or other reasons.

Other infections of note include pertussis, or whooping cough, an outbreak of which the county and state have been dealing with for a number of years. Salmonella, strep, chickenpox and giardia were also among the top 20 reported conditions.

The report also highlights a now continuing hepatitis A outbreak in the county, with at least 100 cases reported last year and another 80 or so this year. The report indicates 30 cases of West Nile virus were reported in Salt Lake County in 2017. Two-thirds of them were hospitalized and four died from the infection.

Three Utahns contracted measles after a not fully vaccinated child traveled to Myanmar in early 2017. A few cases of norovirus were connected with exposure at local restaurants. And infestations of bats were found at two Salt Lake County high schools last year, though a number of students were treated for exposure and remained largely unaffected.

The report, issued annually, is used to spot trends in infectious disease.

"I hope this report can be a resource for healthcare providers, public health practitioners, community partners and the public, and that it can be used to help target intervention and prevention efforts," Vitek said.