Pennsylvania officials have reported an alarming increase in sexually transmitted infections in a county outside of Pittsburgh as local health experts say young people are more promiscuous than ever.

Beaver County saw a 300 percent increase in HIV and 34 percent increase in gonorrhea among 15- to 24-year-olds in 2017 compared to 2016, and the trend has continued into 2018, according to the alert released early this month.

Rates of STIs in the US have increased significantly in the last three years on record, according to data from the Centers for Disease Control and Prevention, and 50 percent of cases are diagnosed in people aged 15 to 24.

Data suggests rates of sexual activity among teens and young adults have been consistent across the past few decades and use of contraception is increasing, so experts say budget cuts for STD prevention programs may be to blame.

Beaver County in Pennsylvania had a 300 percent increase in HIV and 34 percent increase in gonorrhea among 15- to 24-year-olds in 2017 compared to 2016, and the trend has continued into 2018, according to the alert released early this month

The Pennsylvania Department of Health issued an alert at the beginning of the month that there has been an increase in HIV and gonorrhea cases in Beaver County, located about 30 miles northwest of Pittsburgh.

There was a nearly 300 percent increase in HIV among 15- to 24-year-olds in 2017 compared to 2016.

Gonorrhea cases saw a 34 percent increase among the same age group, which is nearly double the national increase during that time period.

Health officials say there's been a similar trend in Allegheny County, the second-largest county in the state where Pittsburgh is located.

'Our incidence rates for syphilis, chlamydia, gonorrhea and HIV have and continue to exceed the state's incidence rates,' Dr Karen Hacker, Allegheny County health department director, told KDKA.

Earlier this month, health officials in Milwaukee, Wisconsin, revealed that at least 125 people had been diagnosed with HIV, syphilis or both.

The 'cluster' is being treated as a city-wide health issue particularly among people between the aged of 15 and 24.

Dr Frank DiCenzo, an OB-GYN in Pittsburgh, claims that the increase is a result of teens being more promiscuous in recent years.

'I've seen high school students who tell me they've had multiple sexual partners,' DiCenco told KDKA.

'Ladies as young as 14. And they have what they call sex partners. Someone that is a friend that they have sex with.'

Additionally, Dr DiCenzo said he thinks they are less likely to be using protection.

However, available data does not support either of those conclusions.

The most recent national data indicates that rates of sexual activity among adolescents and young adults have not changed in the last two decades, but there has been an increase in contraceptive use.

In 2015, 30 percent of teens indicated that they were sexually active, meaning they had had sex at least once in the preceding three months, and 41 percent had had sex at least once in their lifetime.

The number of teens who reported having had four or more sexual partners was 11.5 percent between 2011 and 2015, down from 19 percent in 2002.

Data from 2011-2015 shows that 81 percent of female teens used some type of contraception when they first had intercourse, up from 74 percent in 2002.

Similarly, 77 percent of male teens used a condom during first intercourse, up from 71 percent in 2002.

From 2008 to 2014, the number of HIV cases in the US declined 18 percent.

However, national rates for gonorrhea, syphilis and chlamydia have increased in each of the last three years on record - 2014, 2015 and 2016.

Experts say a decrease in funding for STD programs may be behind the increase in rates.

According to the CDC, more than half of state and local programs experienced budget cuts.

'One big challenge is cuts to STD control programs that means public health is constantly being asked to do a bigger job with diminishing resources,' Fred Wyand, director of communications at the American Sexual Health Association told Daily Mail Online.

'This a a discussion with much nuance and not a single, simple answer but public health advocates consistently report to an eroding STD prevention infrastructure as a key element in driving STD rates.'

In February, Pennsylvania's Allegheny County opened a clinic that exclusively treats STDs and HIV in response to the increasing rates.

Health officials in the area warn that anyone who is sexually active get tested because often symptoms take weeks or months to appear or never present at all.