Source : Webster's Revised Unabridged Dictionary (1913)

Malarial \Ma*la"ri*al\, Malarian \Ma*la"ri*an\, Malarious
\Ma*la"ri*ous\, a.
   Of or pertaining, to or infected by, malaria.

   {Malarial fever} (Med.), a fever produced by malaria, and
      characterized by the occurrence of chills, fever, and
      sweating in distinct paroxysms, At intervals of definite
      and often uniform duration, in which these symptoms are
      wholly absent (intermittent fever), or only partially so
      (remittent fever); fever and ague; chills and fever.

Source : WordNet®

malarial
     adj : of or infected by or resembling malaria; "malarial fever"