What is 'brain-eating amoeba' that took lives of 3 children in Kerala?

Amoebic encephalitis is a rare yet deadly infection of the central nervous system caused by free-living amoebae found in freshwater, lakes, and rivers.
 

There are two types of amebic encephalitis, namely primary meningoencephalitis (PAM) and granulomatous amebic encephalitis (GAE).

PAM typically occurs when people swim in warm freshwater bodies, such as lakes and rivers, where Naegleria fowleri is present.
 

Naegleria fowleri infects people when water containing the amoeba enters the body through the nose, such as when diving into water.
 

Initial symptoms include headache, fever, nausea, vomiting and later symptoms include stiff neck, confusion, loss of balance, seizures, hallucinations.

Recently, three children from Kerala's Kozhikode, Malappuram and Kannur died due to amoebic meningitis within 2 months.