Question

Which type of viral hepatitis is caused by drug use or sexual activity?

Answer 1

That would be Hepatitis C.

Explanation:

The existence of the Hepatitis C virus was first suspected during the 1970's, and finally confirmed in 1989.

It is primarily transmitted via blood/blood contact: Transfusion with infected blood and use/sharing of dirty needles are the main causes.

Blood transfusion is quite safe these days, in the developed world there's a chance of roughly 1 in 2 million to catch it that way.
In developing countries the risk is higher, mainly due to unsafe medical practices.

The chance of sexual transmission is low in general, though practices like penetration of the rectum (had to rephrase this, this editor ticked me off!), genital ulceration or presence of HIV will result in greater risk.

Regarding the symptoms:
A newly infected person won't show any symptoms at first, though in some instances jaundice, a darker urine, abdominal pains and other vague and mild symptoms may occur. It often leads to Liver failure , and sometimes Cirrhosis.

Recovery:
With the right treatment, 90-95 % of the cases will clear the virus.
Sometimes the infection clears without treatment, though these cases are rare....