Pathogenicity and Epidemiology of Hepatitis C Virus

Written by Mona Hadi Naeem
7 · 05 · 18
Pathogenicity and Epidemiology of Hepatitis C Virus

Lifestyle Glitz - Hepatitis C VirusHepatitis C is a major disease of the liver and numerous people around the world suffer from this condition. It can be a leading cause of death in the future as it inflames the liver. In chronic cases, it can lead to complete liver dis-function. It is found almost everywhere and can gain entry into the body of susceptible hosts easily. The Hepatitis C virus is difficult to eradicate due to multiple reasons such as the occurrence of the virus, chronic infection, and the risk factors associated with the incidence of the virus globally. Since there is no vaccine against the Hepatitis C virus until now, it is important to adopt primary preventive measures such as safe use of surgical instruments, regular screening of blood, eradicating drug use, and avoiding intimate contact with the infected person. It is also important to educate people about the deadly disease and its prevalence.

Epidemiology of Hepatitis C Virus

The epidemiology of Hepatitis C Virus relies largely on the study of its serotypes. The studies involve people who are in direct contact with the virus such as those that are not part of the community and reside in areas not included in the community. These also include people who suffer from chronic liver diseases and frequently exposed to blood transfusion. It is easy to gather data from people who represent the entire community rather than on people that live in far off places.

Until now, the data submitted and reported is one that the World Health Organization has obtained from the already present data and excessive research. The Hepatitis C Virus is ubiquitous and presents all over the world, but its prevalence depends majorly on the geographical locations. In developing countries, the rate of prevalence of the virus is less, which includes Northern, parts of America, Europe, and Australia. Under developed countries, such as parts of Asia and Africa have the highest prevalence rates of the Virus.

Frequency of Cases

Considering the developed world and data from different regions and populous countries, the prevalence of serotypes of Hepatitis C Virus is high in Germany (0·6%), Canada (0·8%), France (1·1%) and Australia (1·1%). In the United States, Japan, and Italy the presence of serotype is comparatively higher than it is in other countries and is 1.8%, 1.5-2.3%, and 2.2% respectively. In developing countries, it is easy to gather the data in comparison with the developed countries. The population also plays a major role.

The seroprevalence in China is 3.2% and it contributes one-fifth of the world. India is also one of the most populated countries and has a prevalence rate of 0.9%. In Indonesia, data from the patients who gave their blood voluntarily showed a prevalence rate of 2.1%. In Pakistan, the rate of Hepatitis C Virus incidence is 2.4-6.5%. These figures come from vast study and research. The highest prevalence of serotypes of Virus is in Egypt where the population is 73 million people and prevalence rate is 22%.

Pathogenicity of Hepatitis C Virus

The Hepatitis C virus is an enveloped virus that is small and belongs to the Flaviviridae family. The genome of the virus comprises RNA. After entering the susceptible host, the virus resides in the bloodstream and replicates over there. Besides this, the virus can also invade the other tissues, like the liver, thyroid, pancreas, B and T lymphocytes, bone marrow, spleen, and adrenal glands. According to the studies, it is clear that major site of invasion of Hepatitis C virus is liver and it affects almost 10% of the liver cells. However, if the virus attacks other sites of the body, it may not be easy to recognize and the infection can spread easily as the immune system cannot eradicate it from the body easily.

The E2 and E1 proteins present in the virus mediate the entry of the Hepatitis C Virus in the body. The virus attaches to the membrane of the host and then gains entry into the body through endocytosis. Once it enters the cytoplasm, the RNA molecule replicates and the virus synthesizes new RNA molecules. Then they pass onto the surface of host cells so that they can infect other hosts when moved out of the body.

Infection and Mutation

Once present inside the body, the virus replicates at a high rate, which is almost 1 × 1012 virions per day. When the virus is present inside the body of host cells, it replicates at a high rate and can affect the immune system of the host cells. However, mutations can take place that will produce resistant strains and it produces distinct genomes. These mutations result in the formation of quasispecies. In case of chronic Hepatitis C, the quasispecies is responsible for fibrosis.

Mutation in the genome of the virus can result in various genotypes that are somewhat similar in their molecular mechanisms. The incidence of disease by these genotypes also varies. According to the research, genotype 1 is highly invasive and results in rapid disease as compared to other genotypes. It is the most virulent strain in the case of chronic Hepatitis C infection.

Similarly, the genotype 1b has higher chances of cirrhosis and hepatocarcinoma in comparison to genotype 2 and 3. However, according to some researchers, the genotype and number of viruses present have nothing to do with the incidence of infection in the body. Reports say that steatosis is one of the leading factors that are responsible for causing fibrosis in chronic Hepatitis C Virus infection. However, according to the reports, genotype 3 is responsible for steatosis.

However, besides all the studies and research, it is important to control the incidence of the disease and to eradicate the virus as it already one of the leading cause of diseases all over the world. If left unnoticed, it can produce a menace. Introducing the vaccine ca be one of the preventive measures buy still researchers are working on it and adopting strategies to produce a vaccine.

Hepatitis C – Causes and Prevention

The cause of Hepatitis is the Hepatitis C virus. It can cause mild to severe liver dis-function and can last from few months to even years. This is one of the leading illnesses that prevails around the world and if not controlled can cause menace. If one does not take treatment to remove the virus from the body, it will lead to acute liver inflammation, cirrhosis, scarring, liver cancer, and even death. Currently, reports say that around 71 million people all over the world suffer from this deadly disease.

Hepatitis C virus is a blood-borne virus that is present all over the world and its geographical distribution varies according to the location and concentration of the population. In various locations, multiple strains are present which can affect the population. The presence of Hepatitis C Virus around the world occurs in various forms known as genotypes. The common genotype of virus in Europe and North America is type 1 genotype. The incidence of type 2 genotype is less but is also prevails in America and Europe. In Africa, Asia, and the Middle East, other types of genotypes are reportedly the cause of this deadly disease.

Symptoms of Disease

The common symptoms of hepatitis are easy bruising, easy cutting of skin, loss of appetite, yellow color of the eyes and skin, swollen legs, change in color of urine, protruding out of veins, itchy skin, and much more. However, the symptoms of the disease vary according to the prevalence of the virus, which could be acute (short-term) or chronic disease (long-term). Acute hepatitis is curable with proper care and its symptoms include nausea, loss of appetite, abdominal pain, and lack of energy, fever, and joint pain.

Reports say that the people who suffer from the acute infection get rid of the virus within 8-12 weeks of treatment along with proper care. However, the chronic illness has severe outcomes, which keeps on damaging the liver with the passage of time. The symptoms of the chronic infection include tiredness, irritation on skin, the muscle and joint pain and ultimately fibrosis and cirrhosis. In the start, the symptoms of chronic infection are not apparent and the body goes on experiencing damage for many years, which ultimately results in the complete failure of the liver function.

Causes of the Virus Transmission

The major cause of the spread of the Hepatitis C virus is unsafe and unhealthy contact between the bodies such as have unsafe sexual activities and during pregnancy from an infected mother to the child. The virus is not transmissible through sharing of food, kissing, hugging, or breast milking. However, the major causes are sharing of the infected syringes between the people or improper sterilization of equipment. Transfusion of the blood products or blood between the patients can also be one of the reasons for the disease. Tattooing the body can also be a reason for the infection but the incidence of this source is less.

Risk factors that can promote the transmission of Virus

  • Injecting illicit drugs
  • Organ transplantation
  • A family history of people infecting with Hepatitis C virus
  • Had hemodialysis procedures for long
  • Have been a victim of HIV
  • Done tattooing on any part of the body

Treatment

The Hepatitis C virus can be treated using antiviral medications and safe use of these medicines can eradicate the virus from the body completely. However, administration of the medications must be proper, depending on the genotype of Hepatitis C virus, whether the body had treatment for the hepatitis infection before or not, and depending on the extent of liver damage. Two of the important antiviral medicines used are pegylated interferon and ribavirin, which allow the immune system to attack the virus and prevent the virus from replication, respectively.

In many parts of the world, new medicines are coming up and already existing ones are useful in combination with other drugs that increase the cure rate of disease by up to 90 percent. Some better drugs that are suited to people and that offer fewer side effects are DAAs (Direct Acting Antivirals). These are in use all around the world but the drawback is that DAAs are expensive to buy and use. Besides using medicines, care is also important such as avoiding alcohol, consuming healthy food and mitigate the use of excessive drugs.

Prevention of Hepatitis C Virus

Until now, there has been no vaccine available against the Hepatitis C virus and thus the prevention of the incidence of the disease depends upon the mitigating the exposure of virus in the healthcare settings and preventing the unhealthy activities of sharing equipment. People should make efforts so that sexual activities are controlled and people use properly sterilized instruments.

However, the preventing measures must be adopted with include both primary and secondary prevention which has been devised by World Health Organization.

Primary prevention:

  • Proper use of gloves while working
  • Hand hygiene is important in the preparation of surgical equipment
  • Safe use and disposal of syringes and surgical equipment in use
  • Handle the waste products and sharp equipment with care and dispose of in a proper way
  • Taking care of the individuals involved in using contaminated syringes
  • Checking the blood for any disease because transfusing into other patients
  • Train the health professionals for being safe and practice cleanliness
  • Usage of condoms must take place properly
  • Avoid the use of blood-stained equipment
  • Practicing safe sex can also be a primary preventing measure against the Hepatitis C virus
  • Eradicating the use of illicit drugs, especially if they are being taken orally

Secondary and Tertiary Prevention of Hepatitis C Virus

  • Educating the people about the incidence and harmful aspects of infection
  • Routine screening of blood
  • In case of any incidence, look for antiviral therapy immediately
  • Regular monitoring of liver for checking the incidence of liver disease
  • Avoid tattooing the body
  • Immediately address the doctor if someone is the carrier of the virus

More about Hepatitis C Virus
Hepatitis C is one of the leading diseases in the world and developing countries. The major source of the diseases is Hepatitis C virus that affects the liver. Hepatitis C infection (or HCV), is caused by single-stranded RNA infection that is distantly related to the flaviviruses, despite the fact that hepatitis C is not transmitted by arthropod vectors. A few genotypes have become prominent in numerous nations. Hepatitis C infection seems to have a connection to acute chronic diseases and in some parts of the world, people believe that it leads to the liver cancers.

During the early stages of the disease, the virus remains in the liver of the infected patients with no obvious symptoms. Initially, no symptoms are visible but in fewer cases, fever, abdominal pain, dark colored urine, and yellow colored skin are visible symptoms. However, in chronic cases dilation of blood vessels of esophagus and stomach, liver cancer and even liver failure happen.

Transmission of Virus

The primary cause of the disease remains unknown in most of the cases but still, there is some data available. In developed countries, the major route of the transmission of the virus is via intravenous drugs whereas in developing countries the transmission of the disease is through sexual intercourse and sharing of personal equipment.

Drug Use

In many parts of the world, the major cause of the disease is the use of intravenous drugs. In a survey of almost 77 countries, 25 of the countries have the prevalence of Hepatitis C and almost 60-80% of the people who use drugs are a carrier of the disease.

Healthcare Exposure

Blood transfusion, transfusion of blood items, or organ transplants without HCV screening is one of the noteworthy dangers of the disease. The individuals who have encountered a needle stick damage from somebody who was HCV positive have around a 1.8% possibility of in this way getting the infection themselves. Hospital equipment often leads to the transmission of hepatitis C. These include reuse of needles and syringes; different utilize pharmaceutical vials; infusion bags; surgical instruments among others. Many such hospital instruments have been a leading cause of disease in Egypt where the incidence of the disease is very high.

Unsafe Sexual Intercourse

Unsafe sexual intercourse is also one of the risks of Hepatitis C infection. Therefore, it is important that the people should stick to one sexual partner and avoid having sex with multiple partners.

Shared Personal Items

The transmission of HCV does not take place through food or water and through kissing or hugging. However, sharing of personal equipment can be one of the causes of transmission. Personal care equipment includes toothbrush and razors contaminated with blood.

Mother-to-child Transmission

This occurs in less than 10% of the pregnancies. Long labor, gestation period, and delivery can all be the cause of disease. During breastfeeding, it is important to take special care.

Diagnosis

Various diagnostic tests are present for Hepatitis C but they do no help distinguish between the chronic and acute infections. These tests include HCV antibody-enzyme assay, commonly known as ELISA, HCV RNA Polymerase Chain Reactions and recombinant immunoblot assay. PCR method is a rapid one as compared to the antibody method. These tests are valuable as they can measure the high liver enzyme levels in the body during infection phase.

Serology

Using an enzyme bioassay, detection of the Hepatitis C infection is by measuring the presence of antibodies. If the test results are positive, immunoassay confirms it by a confirmatory test and viral load is calculated. A recombinant immunoblot assay confirms the immunoassay and determination of viral load take place through the HCV RNA polymerase chain reaction. The immunoblot is positive if there appears no RNA and the person has some previous infection. If negative immunoblot appears then the test went the wrong way.

Rapid test

As the name suggests, this test provides the results within 20minutes and is a method approved by the Food and Drug Administration (FDA). If not, lab technicians can process the blood from the vein and in the laboratory. A positive test will show that the person is a carrier of the virus but that does not necessarily mean that Hepatitis infection is present.

Biopsy

In some cases, liver biopsies are necessary to check the level of liver damage. The changes in the lymphocytes are visible in the areas of lymphoid follicles, parenchyma, and bile ducts.

Screening

Screening is usually important for those people who have high levels of liver enzymes as it occurs mostly in the cases of Hepatitis C infections. The simple test is the HCV antibody screen test and is recommendable for the people who have a high risk of the disease. If the results are positive then another test is needed called the HCV RNA. This test will determine that whether the virus still prevails in the body or not.

If after all the infection is confirmed, repeated testing is done to establish the genotype of the virus which will then determine the medications required for the treatment of disease, for how long the treatment is to be carried out and what are the chances of being cured of the chronic disease caused by Hepatitis C virus.

Development of Vaccine

Until 2016, there was no approved vaccine against the hepatitis C infection. The use of new needles and syringes in the hospitals and among the drug users can reduce the infection by up to 75%. The screening of blood givers is vital at a national level, as is sticking to widespread insurances inside medicinal services offices. In nations where there is an inadequate supply of clean syringes, administration of medicines should be oral as opposed to by means of infusion (when possible). Problems in immunization advancement incorporate the succession decent variety between viral gatherings and the significant grouping heterogeneity among separates in the N-terminal district of E2/NS1. Scientists have still not succeeded in finding killing antibodies.

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Mona Hadi Naeem