Question

why malarial concepts called hypothesis ?

Answer 1

When Charles Louis Alphonse Laveran discovered that malaria was caused by a protozoan parasite in 1880, the miasma theory began to subside. ... In the early 1890s Manson himself began to formulate the complete hypothesis, which he eventually called the mosquito-malaria theory.

Answer 2

Back in 19th century when malarial spread was on peak, scientists start to give hypothesis about how malaria is spreading among people. They were many hypothesis; true or false. Some worked, some didn't.

Today, the reason of malarial spread is known and scientists are developing medicines to treat it. So it can said that these hypothesis are no more hypothesis.