As workers move to North Dakota for the state’s growing oil industry, HIV cases in the state are spiking along with the population, The Associated Press reports.

Although HIV rates remain low compared with the rest of the nation, the number of people living with the virus in North Dakota more than doubled between 2007 and 2013. State records from last year showed 230 people living with HIV in addition to 127 people with AIDS.

Lindsey VanderBusch of the state’s health department said the demographics of HIV are changing. In earlier years, cases were focused in larger cities such as Fargo and Grand Forks in the eastern part of the state. Today, 35 to 40 percent of cases are in the northwest, where the oil camps draw tens of thousands of workers.

The oil boom has also been linked with increases of drug use, prostitution and rates of syphilis, gonorrhea and hepatitis C.