Professional football is a hotbed for viruses according to former Chelsea doctor Eva Carneiro.

Mikel Arteta and Callum Hudson-Odoi are just two of the people involved in the sport to test positive for coronavirus (also known asCOVID-19), with the spread of the virus resulting in football leagues around the world being suspended.

While it wouldn't be unreasonable to assume that professional athletes following strict diets at their physical peaks would be among the least affected by coronavirus, they are in fact very susceptible.

"Professional players have been shown to be regularly immunosuppressed," Dr Eva Carneiro said, as per the Daily Mail. "This has been demonstrated by both blood tests and the rate and incidence of upper respiratory tract and other infections, which is how a virus like this starts.

"That's due to the amount of sport they play. The physical activity, playing at a professional level, with games sometimes every 72 hours, as well as training creates a strain on the body," Dr Carneiro added.

With all the various cup competitions, intense league campaigns and international football, it is not uncommon for a player at the top level of the game to be playing three times a week consistently.

That strain on the body impacts their immune system and its ability to fight off infection, increasing a player's chances of catching a virus.

Fatigue isn't just caused by the amount of fixtures though, it is also enhanced by the amount of travelling involved which exposes footballers to more risks.

"It means they have to enter an airport even though they might be travelling by private jet," Dr Carneiro said. "Travel can also mean a change in sleep patterns, arriving back in the early hours of the morning, creating a fatigue which again can make players susceptible.

"They also are part of families who are exposed to the greater community," Dr Carneiro continued. "Fixtures also mean exposure to other teams, staff, nationalities, the latter having regular travel exposures of their own, with differing immunity profiles."

Viruses can also spread through footballers due to the tactile nature of the sport.

Steve Bruce announced in February that he had banned his players shaking hands at Newcastle's training ground, while the pre-match handshake in Europe's top leagues was also ditched.

Dr Carneiro, who now works as a Sports and Exercise Medicine Doctor at The Sports Medical Group in London following a six-year spell at Chelsea, said a desire from teammates to see each other despite being ill makes the control of viruses harder.

"Culturally, it can be hard to persuade players and staff to change the behaviours which cause the spread of infection, like hand-shaking and hugging," Dr Carneiro said.

"Though you might want a player to go into isolation, this is poorly tolerated and there's a natural desire from others not to want the individual to be isolated. That requires supervision and negotiation.

"This time it's not just doctors trained in infection control who are fighting the spread," Dr Carneiro added. "That's something we've not seen before in football. But we are not dealing with a known entity here."

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