The reason Hunters cannot be infected with the Flood is the Hunters are not one creature. They are a lot of little worms that form into one big killing machine, and so, do not have a central nervous system..
Also question is, are hunters immune to the flood?
Lekgolo (Hunters and Hunter Worms): Due to Hunters being massive colonies of individual Lekgolo worms, and due to the Lekgolo lacking a central nervous system and biomass, they are, collectively, immune to Flood infection. Lekgolo cannot be properly infected, if they even can be.
One may also ask, what happens when a Spartan is infected by the flood? Spartan - Iron Spartans have always been able to be infected, the trick is an infection form getting under the thick armor and bodysuit that laid underneath. In the Flood, an infection form jumped onto the Chief and tore the bodysuit near his neck, had Cortana not zapped the thing off of him, he would've been infected.
Likewise, people ask, can grunts get infected by the flood?
They aren't immune to the flood, the flood just uses them for raw biomass instead of as combat forms. Similar case with jackals.
How does the flood infect?
The Flood infects any sentient life of sufficient size. The Flood-infected creatures, also called Flood, in turn infect other hosts. The parasite is depicted as such a threat that the ancient Forerunners killed themselves and all other sentient life in the galaxy in an effort to stop the Flood's spread.
Related Question Answers
Who created the flood?
Ten million years before the Forerunner-Flood war, the Forerunners rose up and destroyed their creators, the race of beings known as the Precursors, in a massive war. The Forerunners were refused the Mantle by the Precursors and the Forerunners retaliated, driving the Precursors out and killing almost all of them.Does Halo 4 have floods?
Flood infected players in the Flood infection game type. Flood is the Halo 4 successor to the Infection gametype featured in Halo 3 and Halo: Reach. It is the first time in the entire series that a player is able to play as a member of the Flood.What are hunters in Halo?
Hunters. The Mgalekgolo (Ophis congregatio, meaning "serpent union"), more commonly known as Hunters, are a unique gestalt of smaller creatures known as Lekgolo, which are tiny, orange, worm-like creatures that group together to exponentially increase their intelligence, strength, and maneuverability.Why is Sgt Johnson immune to the flood?
The current canon is that Johnson has a resistance to Flood infection due to his ORION augmentations. This more than likely played a role in his ability to survive the Flood horde on Installation 04. He is not, however, immune.How tall are Grunts in Halo?
Grunts are about 5 1/2 feet tall on average and are relatively weak compared to other Covenant species. Although they can easily walk upright on two legs, they are often seen using their arms to move in a quadrupedal fashion.Are the precursors the flood?
The Primordial, a Gravemind that identified itself as the last Precursor, revealed that the Precursors had been ruthlessly killed in a war with the Forerunners millions of years before the events of Halo and that "their answer is at hand" - implying that a proto-Flood form (described as a fine dust contained inHow tall are Flood Infection Forms?
Height. 87.5 - 130 cm. (2 ft. 11 in.What is the gravemind Halo?
The Gravemind is a parasitic, hive mind intelligence in the Halo universe. While only one Gravemind is ever seen in the games, the title is given to the final stage of Flood evolution, in which the Flood becomes a superorganism.How did Johnson survive the flood?
Johnson was immune to the Flood from his Orion Project modifications that were the basis for all the future Spartan programs. Once he survived the Flood he evacuated onto a Pelican with a few more Marines and a pilot. They all hid on the nearby moon. So Johnson was nowhere near Halo when it was destroyed.Is the flood still alive?
Deceased
Why did the covenant release the flood?
How did the Covenant release the Flood if they cannot activate Forerunner mechanisms? The Forerunners kept the Flood around in the hopes of finding a cure. Its source was from god-like, extragalactic aliens. They knew that their victory against them was likely only temporary.How tall is Master Chief?
2.13 m
What is flood explain?
A flood is an overflow of water that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods often cause damage to homes and businesses if they are in the natural flood plains of rivers.What is the purpose of the Halo rings?
The ring holds religious significance to the aliens, while the humans believe it is a weapon that could turn the tide of the war against the Covenant in their favor. In reality, the ring is home to a virulent parasite called the Flood, which is accidentally released by the Covenant and threatens to infest the galaxy. 
