The Collaborative International Dictionary of English v.0.48:

Malarial \Ma*la"ri*al\, Malarian \Ma*la"ri*an\, Malarious
\Ma*la"ri*ous\, a.
   Of or pertaining, to or infected by, malaria.
   [1913 Webster]

   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.
      [1913 Webster] malaria mosquito

WordNet (r) 3.0 (2006):

malarial
    adj 1: of or infected by or resembling malaria; "malarial fever"

Moby Thesaurus II by Grady Ward, 1.0:

40 Moby Thesaurus words for "malarial":
   allergic, anemic, apoplectic, arthritic, bilious, cancerous,
   chlorotic, colicky, consumptive, dropsical, dyspeptic, edematous,
   encephalitic, epileptic, laryngitic, leprous, luetic, malignant,
   measly, nephritic, neuralgic, neuritic, palsied, paralytic,
   phthisic, pleuritic, pneumonic, pocky, podagric, rachitic,
   rheumatic, rickety, scorbutic, scrofulous, tabetic, tabid,
   tubercular, tuberculous, tumorigenic, tumorous