There is some evidence for prior Tuberculosis infection leading to the development of lung cancer. Studies have also looked at Chlamydia pneumoniae and HPV infections possible etiological agents but the verdict is still out on those. (as of Sept. 2011)
What is the causative agent that caused you to ask this question
The causative agent of the symptoms of tetanus is Clostridium tetani.
The causative agent of syphilis is the bacterial spirochete called Treponema pallidum.
The genus of the causative agent of malaria is Plasmodium. It belongs to the group of protozoa.
The causative agent for Hepatitis B is Hepatitis B virus.
Rhinoviru
Rabies virus is the causative agent for rabies.
HIV is the causative agent for AIDS. It attacks the T Cells of the body.
The polio virus.
Fungus
Mycobacterium tuberculosis, the causative agent of TB
streptococuss