WHO says nearly 42,000 Gazans, including thousands of children, have suffered life-changing injuries such as amputations and spinal damage.
US President Donald Trump implored pregnant women to avoid taking the painkiller Tylenol, the bestselling form of acetaminophene.
The virus was registered in Iraq in the late 1970s of the last century, and it mostly grows in rural areas. Those who breed cattle are mostly vulnerable.
Widespread malnutrition in Gaza is preventing many from donating blood, worsening shortages as hospitals struggle to treat the growing number of wounded.
The WHO said that 75% of UN missions have been denied access to Gaza amid a critical shortage of food, medicine, and other essential supplies
Dr Ahmed Al-Qirm, at Al-Ahli Baptist Hospital, remarked to The New Arab, "They were all killed by Israeli bombing... but the hunger was clear on their faces."
The outbreak in the south of the country followed a reported drone strike on a power station, disrupting access to clean water in the city of Kosti.
Newly confirmed Health Secretary Robert F. Kennedy Jr. on Thursday accused US institutions of "stealing the health of our children".
The Ministry of Health has launched targeted campaigns to vaccinate against measles virus, urging the public "to trust the science."
The US' withdrawal from the World Health Organization will deal a major blow, as Washington is its biggest funder.