Malarial is the adjective that belongs to malaria, the mosquito-borne disease of hot countries.

Malarial這個字 is the adjective that belongs to malaria是malaria（瘧疾）的形容詞形式，the mosquito-borne disease of hot countries瘧疾是熱帶地區由蚊子傳染的疾病。

A malarial fever is a fever of that kind; a malarial mosquito is one that can carry the parasite; a malarial region is a place where the disease is common; malarial parasites are the tiny living things in the blood. You do not say someone “has malarial” the way you say they “have malaria”; the -al form hangs on a noun (fever, area, mosquito) or, more rarely, stands as a noun in old medical writing for a person suffering from the disease.

A malarial fever瘧疾熱 is a fever of that kind就是那種發燒；a malarial mosquito帶瘧原蟲的蚊子 is one that can carry the parasite指能夠攜帶寄生蟲的蚊子；a malarial region瘧疾疫區 is a place where the disease is common指這種病很常見的地方；malarial parasites瘧原蟲 are the tiny living things in the blood是血液裡那種微小的寄生生物。You do not say someone “has malarial”你不會說某人「has malarial」，the way you say they “have malaria”就像你會說他們「have malaria」那樣；the -al form hangs on a noun (fever, area, mosquito)這個-al的形式要接在名詞後面（像fever、area、mosquito），or, more rarely或者比較少見地，stands as a noun in old medical writing在舊式醫學文獻裡當名詞用 for a person suffering from the disease指患有這種病的人。

It has no extra everyday meaning of its own: it always points back to that illness.

It它 has no extra everyday meaning of its own沒有自己額外的日常意思，it always points back to that illness永遠都是指回那個疾病。