Parasitic Encephalitis is caused by -

Naegleia fowleri The amoeboid form enters the human body through nasal mucosa. The parasite invade the cribriform plate and travels along the olfactory nerve to brain leading to a rapidly fatal infection known as primary amoebic meningoencephalitis It occurs in young adults and children with arecent history of swimming in fresh water (refer pgno:25 baveja 3rd edition)