6 Pathogens That Are Silently Killing You

Thanks to the lymphocytes of the immune system our white blood cells and cells called antibodies made by B cells can protect us from most infections: virus, bacteria, or some other pathogen. However, there are few special cases where the immune system either cannot control the attack on a pathogen, or doesn't attack because it is not aware of its presence in the first place.

1. Varicella zoster virus causes chickenpox and shingles, and it only affects humans. There is a vaccine for this disease, and that's your best hope at not becoming seriously ill.

2. Measles virus

3. Human Immunodeficiency virus. You've heard of this one right? And there's no vaccine… yet.

4. Mycobacterium tuberculosis causes, you guessed it, tuberculosis. It's controlled in most developed countries, but undeveloped and developing countries aren't doing so well in that arena.

5. Bacillus anthracis causes anthrax, an especially lethal endospore-forming bacterium that uniquely synthesizes a protein capsule that produces a lethal factor.

6. Toxoplasma gondii is a parasitic protozoan that causes toxoplasmosis; it feels like a flu but worse, and cats are infamous carriers of this pathogen.