what type of pathogen can cause an sti
Some infections that can spread through sexual contact, such as the common cold, spread more commonly by other means. These infections are not considered STIs. Pathogens that Cause STIs. STIs may be caused by several different types of pathogens, including protozoa, insects, bacteria, and viruses.For example: Protozoa cause an STI called trichomoniasis. The pathogen infects the vagina in females and the urethra in males, causing symptoms such as burning and itching. Infection with HPV. 2  can be prevented with a vaccine. 3  can cause hepatitis B. 4  is very common in young men. 5  all of the above. 6  Syphilis. 7  can cause serious damage to the heart, brain, and other organs. 8  causes small sores on or near the genitals. 9  if untreated, may eventually lead to death.