(CBS News) The Centers for Disease Control and Prevention says 2012 has been the worst year for the West Nile virus since 2003.
There have been nearly 2,000 cases of the disease so far this year, and 87 Americans have died.
The virus has been reported in 48 states this year, with almost 45 percent of cases in Texas. Another quarter of all cases have been reported from South Dakota, Mississippi, Oklahoma, Louisiana and Michigan.
Also, a Hanta-virus outbreak has killed three visitors to Yosemite National Park.
There was a case of bubonic plague last week in Colorado, while a big jump in the tick population could mean an upsurge in Lyme disease.
Dr. William Shaffner, past president of the National Foundation for Infectious Diseases, said the recent up-tick of infectious diseases is due, in part, to climate.
"We've had a very, very warm winter and summer, and the drought has got something to do with it also, Dr. Shaffner said on "CBS This Morning."
Of West Nile, he said, "You would think in a drought there wouldn't be many mosquitoes because mosquitoes transmit that infection to us. But it turns out in those few standing water sources, that's where mosquitoes breed, the birds comes down to feed there, the mosquitoes bite the birds, pick up the infection and then sometimes transmit it to us.
"The West Nile virus can cause an illness with fever, but particularly among older people, people older than age 50, it can cause encephalitis and then sometimes prolong systems after people recover."
The symptoms, he said, "look a little bit like the flu. Most people who get infected don't become ill. If you become ill you have this minor flu-like illness. But a few people get the serious nervous system complications."
The source of infection or Hanta virus, Dr. Shaffner said, are deer and mice. "They are looking for food and water and so their droppings are inhaled sometimes by us and then we get sick."
Symptoms: "Initially you get fever, feeling poorly, and then you can a pneumonia-like illness that can be very severe and also kidney failure."
"Is this something we have to start living with?" asked Charlie Rose.
"We have to live with it, because we go out into the wild and we encounter these infections that are in the animal world, in the wild, and we're at risk of getting them," Dr. Shaffner said.
So what can people do to prevent the spread?
Dr. Shaffner said that, with West Nile, "Try to avoid mosquito bites. Use repellent, long sleeves, long trousers. Look for standing water around your house and get rid of it, including in your gutters.
"With Hanta, if you go out, don't let mice eat your food. Keep it away from the mice. You don't want to attract the bears or the mice."
And for Lyme disease - which are transmitted by tick bites - Dr. Shaffner said, "You also always want to inspect yourself, and have somebody look on the back of your head and back of your back to see if you've had a tick bite. Fortunately tick bites are common but Lyme disease is very uncommon, relatively speaking."
Gayle King asked about a recent report of a case of Bubonic plague - a little girl whose parents first thought she had the flu.
"She saw a dead squirrel, I think covered the squirrel...she wanted to bury it with the T-shirt," said Dr. Shaffner. "Some of the fleas got on the T-shirt and then bit her."
He said flu is often the initial illness: "You get a flu-like illness, you're feeling poorly, you've had fever and it looks like just some sort of common infection. What you need is an astute doctor and a history of the exposure."
"There was a great fear of Asian flu and then it was not as severe as we expected," Rose said. "What's been the consequence of that?"
"We have periodic episodes of influenza with new influenza strains," said Dr. Shaffner. "They usually come from Asia. The last one came from Mexico. Those viruses, they don't need passports, so we live in one world and so we need strong public health in order to be able to respond to these infectious threats which are always around us.
"I know it's the 21st century, but those infections are still with us."
To watch a video of Dr. Shaffner's interview click on the player above.