HIV cases are on the rise in Ventura County, California, leaving health officials scrambling to figure out the underlying causes and how to reverse the trend, reports VC Star, part of the USA Today network.

Preliminary data from the county health department show a total of 92 new HIV cases (including 12 AIDS cases) in 2017, marking a significant increase from 56 the previous year (including seven AIDS cases) and 44 in 2013 (including 16 cases of AIDS).

Health officials and advocates speculate on a number of reasons for the spike in new cases in the coastal region just north of Los Angeles. Chris Ornelas, the director of the Ventura County Health Care Agency’s HIV/AIDS program, tells the newspaper that an increase in HIV testing—particularly at emergency rooms—could explain the higher numbers.

HIV stigma, he notes, remains a challenge to HIV prevention. Then there is the prevalence of dating and hookup apps to consider. In a related article, Ventura advocates call out social networks such as Grindr for making riskier sex more common.

Doug Halter, a Ventura resident who was diagnosed with AIDS in 1987, said he suspects younger people don’t fully understand the dangers of the disease.

The shutdown of several HIV/AIDS groups in the county because of lack of funding may also be contributing to rising rates of HIV infection.

Finally, lack of education about HIV and prevention methods such as Truvada as PrEP (pre-exposure prophylaxis) likely play a role in the surge of HIV cases, notes Joseph Summers of the LGBT group Diversity Collective Ventura County. The group organizes a major effort to tackle stigma and raise awareness: the Ventura AIDS Walk and health fair, which takes place Saturday, March 3. For more information, click here.