Once inside the host, the Hepatitis C virus can remain viable for an indefinite period of time. Outside the body, the virus can be viable and infective for over 3 hours. The virus can multiply in the liver and in the blood cells like lymphocytes.
HCV infection leads to inflammation and death of liver cells. The patient’s immune system plays a crucial role in the control and the elimination of the virus from the body. The immune response is generally triggered in the acute phase of an infection. After the acute infection by HCV, more than 85 % of the patients progress into the chronic state. In chronic hepatitis C, the virus has cleared and the active infection is not present. Unlike the acute phase, chronic HCV infections are usually asymptomatic in initial years. There are mostly identified at the time of routine health check-ups.
Transmission of Hepatitis C Virus
The most common route of transmission, accounting for 50-80% of all HCV cases, is IV drug abuse. The second most common cause is the use of unsafe blood or blood products without HCV testing. While this accounts for only 4% of HCV cases in the USA, in developing countries unsafe medical procedures and untested blood transfusions play a larger role in the transmission of HCV. Since the implementation of universal screening procedures for all blood products before transfusion, the rate of HCV transmission has dropped tremendously. However, there is still some risk as the window period for HCV infection to show in those who donate blood is up to 70 days and HCV testing can be negative in spite of the presence.
Healthcare professionals are at risk for HCV transmission via contaminated needle stick injury. After a stick, there is 1.8 % risk of contracting the HCV infection by the exposed person. Exposure to infected blood on the intact skin does not carry any risk of transmitting the HCV infection. If the person has a cut or breakdown of skin integrity and is then exposed to HCV-contaminated blood or fluids in that area, then there is a risk. Most modern hospitals use disposable medical equipment only. However, in the event of malpractice or by mistake, reuse of infected needles, syringes, dialysis tubes, infusion sets, multiple use vials, non-sterilized surgical blades and other equipment carries a risk of HCV transmission.
The association of high-risk sexual behavior and the HCV infection is controversial. There is a lack of evidence to prove the sexual activity as a route of contracting HCV infection. The rate is very high among those who had unsafe physical relations or who had multiple sex partners. However, the presence of other risk factors cannot be denied in this population. The rate of transmission is high in those who have sexual practices in which there is a risk of trauma to the mucosa by which infection can be transmitted. The rate is also high in the persons who have other sexually transmitted diseases like HIV. The use of a condom can prevent the transmission of HCV infection.
Tattoos also carry the risk of transfer of the HCV infection as the needles and equipment used are non-sterilized. Just like HIV, HCV infection does not spread through casual contact, by sharing food or water. The transfer of HCV infection from mother to her child occur in less than 10 % cases. The risk is very high during the delivery. There is no evidence of the spread of the virus by breastfeeding a baby, however, it should be avoided.