Information about Panama
 

Please stick to the popular touristic beaches. Panama has a narco traffic problem and they drop drugs in isolated beaches. Bad luck would be if you were a witness of a movement

Credit card use in Panama
 

Panama is open to Visa, Mastercard and some businesses even accept unionpay from China.
American Express is almost impossible to use outside touristic places.
I don't recall anyone using discovery.

Common diseases in Panama
 

Panama, as any other tropical country has a problem of mosquitoes. Some of them can infect you of Dengue, Yellow Fever, Zika and Malaria. Risk decreases in cities.
While on dry season, Hantavirus can be something to worry about IF and only IF you are staying at a rural area.
Chagas disease can also be infected if you go deep into the jungle.
In any case, take your vaccines.

There are no vaccines for Chagas, Zika, Dengue or Malaria.

You are right. I was thinking in Yellow fever only.

Three threads have been merged

Are you writing a guide book, or what?