But you're more then welcome to go
There are a lot more cases of flu per year than the 3-5 million *severe* cases cited by the WHO, and there would be even more if so many weren't prevented by the flu vaccine. There also would be more severe cases if it weren't treatable with antivirals. And the severe cases and deaths are mostly elderly, children under 2, and people who already have health issues.
Per the WHO: "Influenza occurs globally with an annual attack rate estimated at 5%10% in adults and 20%30% in children."
http://www.who.int/mediacentre/factsheets/fs211/en/
That's a bucketload of cases annually. With a global population of more than 7 billion people and a 10% annual global infection rate, you're looking at over 700 million people infected each year. With 500,000 deaths, that's less than a 1% mortality rate.
Ebola has a mortality rate of up to 90%. It has no vaccine and no treatment beyond supportive. Up until now, it has been confined to small, rural villages where entire populations were wiped out before it could spread beyond the boundaries of the village.
This outbreak, however, has made it into densely populated cities. The healthcare systems there are so broken that one hospital was described as having a single stretcher used to carry both incoming patients and outgoing highly infectious Ebola corpses. They run out of gloves, there is a worldwide shortage now of protective clothing, they hand wash. Nurses have gone on strike because they aren't being paid and don't have protective equipment. A doctor who recently returned wrote of just a handful of doctors trying to care for 50 patients; arriving in the morning to find them collapsed on the floor in pools of blood, urine and feces.
There are now 2 diplomats who have traveled while sick, one violating his quarantined while doing so, and a doctor who secretly treated the 2nd diplomat, continued working and socializing even after his symptoms started, thereby causing it to spread in Nigeria.