Now on the subject of what our friend has seen:
West nile virus.- it 's an animal deasese transmissible to humans, the problem with that one is that it 's transmitted to humans through biological vectors ( mosquitoes ), just like equine encephalitis or malaria or yellow fever.
Avian influenza.- that one has two sides, one is the possibility of transmission to humans ( and become the 1918 pandemia all over again ), the other one is that it 's transmissible to birds, which birds ? the birds we eat so it can wipe out the entire poultry industry of a country, that 's why it is important.
Foot and mouth disease.- it does not transmit to humans but it transmits between hoofed animals ( swine, cattle, goats, sheep ), even though the mortality rate is extremely low the morbility rate is extremely high and the economic cost of it is in the billions, cows, goats and sheep don 't produce milk, swine don 't fatten fast, cattle abort, animals can 't eat nor move, the reason why it was erradicated was the economic cost. Canada, the US and Mexico are foot and mouth disease free and they plan to keep it that way.
Anthrax.- anthrax is what we call a teluric disease ( bound to earth ), for those not familiar with it, take a soil sample from and incubate it on a media like blood agar and you 'll see anthrax colonies growing, in hundreds of places anthrax used to be quite common to find in the cattle and if wasn 't for vaccination in areas where it 's prevalent cattle would not be able to graze. So why the alert ? cuz it was not the ordinary common anthrax what was in those letters, it was biological weapons grade anthrax, a much more virulent strain developed for biological weapons.
Mad Cow disease.- it 's caused by a molecule called prion and causes a degenerative disease in the brain ( spongiform encephalitis ), why the alert ? because if you eat meat contaminated with the molecule you can get it. Also, it can get into our meat chain of production when our domestic animals consume contaminated material in the form of meat and meat by products flour used to feed them.
So, "out of proportion" it depends on how you look at it.