Microbiology :)

is the study of microscopic forms of life.

A is a microbe that harms us. On the other hand, a microbe is one that helps us.

Giving is one of the most common reasons for opportunistic infections as it clears out the flora and gives room for microbes to inhabit.

Infection happens many ways:

You can get measles through exposure to .

Oral transmission can occur through the exchange of , such as when kissing or sharing food/drink. An example is .

is due to direct trauma, such as injections or an bite.

There is also transmission, as is the case with HIV and/or chylamydia.

Sometimes transmission is , such as rubella infections.

Finally, direct skin contact is another way transmission occurs. An example is .

Vaccine failure:

failure
 Individual does not respond adequately

failure
 responds adequately but the immunity fades overtime

An reaction is the main contraindication to a vaccine.

is given as a vaccine to the elderly.

In most western countries, only high risk groups recieve the (for tuberculosis) and