"Over 1.9 million people have been displaced from their homes, of whom over 1.4 million are staying in overcrowded shelters. These conditions are ripe for a continued rise in infectious diseases," WHO said in a statement.
"In Gaza today, on average, there is only one shower for every 4,500 people and one toilet for every 220. Clean water remains scarce and there are rising levels of outdoor defecation. These conditions make the spread of infectious diseases inevitable."
Since mid-October, more than 100,000 cases of diarrhea have been registered in the enclave. Half of those cases occurred in children under the age of five, which is 25 times higher than pre-conflict levels, according to the statement.
"Over 150,000 cases of upper respiratory infection, and numerous cases of meningitis, skin rashes, scabies, lice and chickenpox have been reported. Hepatitis is also suspected as many people present with the tell-tale signs of jaundice," the statement read.
Malnourished children are at a higher risk of dying from diarrhea, pneumonia and malaria, especially when lacking access to life-saving health services, according to the statement.
"An unprecedented 93% of the population in Gaza is facing crisis levels of hunger, with insufficient food and high levels of malnutrition. At least 1 in 4 households are facing 'catastrophic conditions': experiencing an extreme lack of food and starvation and having resorted to selling off their possessions and other extreme measures to afford a simple meal. Starvation, destitution and death are evident," the statement said.
On Tuesday, the UN Office for the Coordination of Humanitarian Affairs said that half of the enclave's population was suffering from severe hunger, with 90% regularly going without food for a whole day.