As concerns about dengue fever spread across Europe, why do mosquitoes bite some people… but leave others alone? And is there anything we eat or drink that repels (or attracts) them?

It’s a situation many of us have faced while on holiday with a partner or friend.

One becomes completely covered in mosquito bites, while the other escapes almost completely unscathed.

And while the red, painful, bumpy bites are bad enough, the buzzing attackers can also spread a host of dangerous pathogens, posing an increasing health risk in Europe.

So what makes one person more attractive to the vampiric bloodsuckers than another?

Here, MailOnline explains what experts think is and isn’t the key behind this phenomenon.

How big you are and how you breathe

Mosquitoes track their prey by their scent and one of the things they hunt for is carbon dioxide.

Carbon dioxide (CO2) is a gas that we exhale as we inhale, and acts as a beacon for the insects.

However, the amount of CO2 does seem to matter. Larger people naturally exhale larger amounts of carbon dioxide and for this reason experts say they are bitten more often.

In the real world, this means that men are bitten more often than women, pregnant women are bitten more often than non-pregnant women, and adults are plagued by bites more often than children.

Dr. Robert Jones, a disease control expert from the London School of Hygiene & Tropical Medicine, said fatter people could also be targeted for this reason.

“Among a group of people, the number of bites from an individual is associated with the proportion of total area or weight that individual contributed to the group,” he said.

The same logic is thought to apply to people with increased breathing, such as those who exercise.

Your natural scent and the bacteria on your body

It is believed that the unique aroma of humans also plays a role in the selection of mosquito victims.

Our natural scent is determined by a combination of our genetics and the skin’s microbiota, the community of microscopic organisms that live on the surface of our flesh.

Tests in which people wear nylon strips to extract their musk, which are then hung in front of swarms of mosquitoes, have clearly shown that the insects have a preference when it comes to certain aromas.

Similar studies in twins have suggested that genetics could explain as much as 67 percent of mosquito attraction.

Although there is evidence that personal aroma accounts for a significant part of mosquito attraction, scientists are still trying to unravel exactly which substances we blow into the air are responsible and what we can do to mask or reduce them .

Dr. Jones said: ‘We believe that genetic factors and our skin microbiome influence the volatile compounds our bodies produce, and this in turn affects how we smell.’

‘Some of these substances have been shown to be attractive to mosquitoes, so if your body produces a lot of these substances you may attract more mosquitoes than other people.

‘We are interested in ways in which these compounds can be masked or their relative abundance changed to make people less attractive.’

Choosing your outfit can make you a target

While smell is a mosquito’s best sense, it’s not the only one where research shows the insects prefer certain colors over others.

Experiments have shown that they have a general preference for red, orange, black or cyan.

In contrast, green, blue or purple colors did not attract the attention of the leeches.

Experts believe that mosquitoes evolved this sense to distinguish between prey and the environment after sniffing them.

Mosquito vision is not the same as human vision and all human skin, regardless of pigmentation, will appear red/orange to the insects.

Experts say people can reduce the chance of mosquitoes biting them by avoiding colors they find attractive.

Does your blood type really make you tastier?

One of the most common beliefs is that your blood type, especially type O, makes you a more desirable meal for mosquitoes.

However, while some studies have shown this to be the case, other tests have been inconclusive.

Dr. Jones said that in general, blood type is probably not an important part of mosquito attraction.

‘There doesn’t seem to be strong evidence that blood types influence people’s attractiveness to mosquitoes. Other factors are more important,” he said.

What about what you eat or drink?

There are claims on the internet that many foods and drinks attract or repel mosquitoes.

Some, like garlic, are promoted under the logic that the strong scent will help mask your own odor and act as a kind of olfactory camouflage.

On the other hand, it is claimed that salty or sweet foods have the opposite effect and produce substances that make us more attractive to mosquitoes.

Even beer may not be a safe option. One study, albeit only among 14 people, showed that mosquitoes were more likely to land on someone after they had had a drink.

But actual evidence that this work is mixed. Several studies have failed to show that what we eat or drink affects mosquitoes, or are very limited in their findings.

Dr. Jones said that given the unreliable nature of using food or drink to repel mosquitoes, people are better off with standard repellents.

“It is much better to use methods that have been proven through rigorous scientific testing to provide a high level of protection against bites,” he said.

‘There are several repellents that are effective for hours against a range of mosquito species and can be used safely by both adults and children.’

It may, for a little bit, be all in your head

Another factor to consider in the mosquito preference debate is that the problem may be you.

Dr. Jones explained that some people react worse to mosquito bites than others.

This can make their bites seem worse, more itchy, larger and more painful, and can even make them appear as if they have been chewed more than someone else with the same number of bites.

What can I do to avoid becoming a mosquito buffet?

Tips to prevent mosquito bites include wearing long-sleeved clothing and pants, using insect repellent, keeping the property’s windows closed or using mosquito screens, and sleeping under a mosquito net.

People should be especially careful in the early morning and early evening, when mosquitoes are most active.