Hep C Risk Factors

  Recently I learned that my father's girlfirend has tested Hep C positive.  I lived there thru the new year and am worried about being infected as well.  My doctor told me that Hep C is only contracted thru blood transfusions and needles, but information on your forum seems to say otherwise.  She (father's girlfriend) says you can get it from kissing, sex, toothbrushes, etc. (exchange of any bodily fluids.)  I am worried that I may have been infected and that I may infect my boyfriend whom I now live with.  My father has never been tested for Hep C, but both he and his girlfriend are past drug users.  Is there a way to know who gave it to who or how long each of them has had it?  
  Confused and Scared.

[HFHSM.D.-D.M.]

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Dear Nicky:
I really appreciated your questions and your fear.  However, I think the more you learn about transmission of hepatitis C, the less you will be scared.  I am always happy to relay information specifically about hepatitis C transmission.  
Spread of hepatitis C requires blood to blood contact.  In other words, infected blood must make contact with your bloodstream.  The two most common ways that hepatitis C are spread in this country are by intravenous drug use and transfusion.  Hepatitis C absolutely cannot be spread by casual contact such as kissing and hugging because it is not in saliva.  It can potentially be spread within families, however, if individuals share razor blades or toothbrushes or other objects that can get blood on them.  
Hepatitis C is not easily transmitted through sex because even here blood to blood contact appears to be required because the hepatitis C virus is not found in semen or cervical secretions.  It turns out that the main risk factor for sexual transmission of hepatitis C is having multiple sex partners.  In fact, two people involved in a monogamous relationship have a very low chance of giving each other the hepatitis C virus even if they have been sexually active for 20 to 50 years.  One explanation for this (that has not been proven) is that people who have multiple sex partners are at a greater risk for sexually transmitted diseases and that venereal sores can allow blood to blood contact.  The current NIH recommendations are that the spouse or partner of someone with hepatitis C be tested, but that even if the spouse is negative that the two individuals not change their sex habits.
You ask the interesting question of whether there are blood tests that can identify if your father (who has not been tested)  and his girlfriend have the same virus and identify who gave it to whom.  There are very sophisticated techniques available in experimental settings that can identify if your father and his girlfriend have the same virus but I don