Doctors are noticing a big increase in the number of Ross River virus cases in the Hunter.
According to Hunter New England Health, there have been 175 confirmed cases so far this year, up from just 33 cases at the same time in 2016.
The recent rain and relatively warm weather has created perfect breeding conditions for mosquitoes.
"We often see a peak coming up to the Easter long weekend, because people love to make the most of the remaining warm weather going camping and having picnics," Dr David Durrhiem said.
If you're heading outdoors, make sure you cover up and use mozzie repellent.
Many people who are infected with the virus will never develop symptoms.
However some people will have flu-like symptoms that include fever, chills, headache and aches and pains in the muscles and joints.
Sometimes a rash occurs on the body, arms or legs. The rash usually disappears after 7 to 10 days.
Symptoms usually develop about 7-10 days after being bitten by an infected mosquito.
The majority of people recover completely in a few weeks. Others may experience symptoms such as joint pain and tiredness for many months.