Medically Important DNA Virus: Hepatitis B Virus

Introduction

Hepatitis B Virus (HBV) is a DNA virus belonging to the family Hepadnaviridae. It is a major human pathogen that primarily infects the liver, causing a wide spectrum of liver diseases ranging from acute hepatitis to chronic infection, cirrhosis, and hepatocellular carcinoma (liver cancer). HBV is highly infectious and transmitted through parental, sexual, vertical (from mother to baby).

What is Hepatitis B Virus?

Hepatitis B virus is a medically DNA virus that primarily affects the liver and causes the disease hepatitis b. it is a viral disease that can be either acute or chronic and affects millions of people around the world. hepatitis b is a viral infection that affects the liver causing inflammation and damage, most people do not show symptoms when newly infected. Some of the symptoms are yellowing of the skin and eyes that is jaundice, dark urine, vomiting, nausea, pain in lower abdomen. When severe acute hepatitis can lead to liver cirrhosis and liver cancer.

 Clinical significance

1. Acute hepatitis:

Acute hepatitis B virus infection refers to initial phase of infection, typically lasting less six months. Many individuals with acute HBV infection are a symptomatic or have mild flu like symptoms. Most individuals recover from acute hepatitis B without complication

2. Chronic hepatitis:

Chronic hepatitis b virus infection occurs when the virus persist in the body for more than six months. Chronic infection can lead to ongoing liver inflammation, progressive liver damage, and the development of liver cirrhosis over time. Individuals with chronic hepatitis b are at an increased risk of complications, Including Liver failure and hepatocellular carcinoma, a from liver cancer.

3. Liver cirrhosis:

Prolonged inflammation and liver damage caused by chronic HBV infection can lead to the development of liver cirrhosis. Cirrhosis is scarring of the liver from long-term damage. It’s serious, but with early treatment and lifestyle changes, its effects can be reduced.

4. Hepatocellular carcinoma of HBV

IS the most common type primary liver cancer. Chronic HBV infection is a major risk factor for the development of hepatocellular.

How transmission hepatitis b virus

HBV is spread when blood, semen, or other body fluids from a person infected with the virus enter the body of someone who is not infected.  

Hepatitis b is a large virus does not cross placenta.  Cannot infect fetus. If not vaccinated at birth they develop a lifelong HBV infection. Hepatitis b virus infection is the only sexually transmitted infection that have a protective vaccine

The main modes of transmission include:

1. Perinatal: HBV can be passed from an infected mother to her baby during childbirth.

2.  Sexual transmission: unprotected sexual contact with an infected person.

3. Horizontal transmission: sharing personal items contaminated with infected blood.   Close contact in households (especially among children in endemic areas).

4. Parenteral transmission: blood transfusion with unscreened or contaminated blood, sharing needles, unsafe  injections with contaminated equipment, needle-stick injuries in healthcare workers, medical procedures done with improperly sterilized instruments, tattooing, piercing, or acupuncture with unsterilized equipment.

Signs and symptoms of hepatitis b infection

1.  Acute hepatitis:

Acute HBV can manifest as an acute illness with a wide spectrum of symptoms. Some people may develop symptoms within 1to 4 months after exposure, but many don’t show any at all.

Symptomatic individual may experience flu-like symptoms such as fatigue, fever, muscle and joint aches, nausea vomiting, and loss of appetite.

Jaundice is a hallmark of acute hepatitis and usually appears after the initial flu-like symptoms.

2.   Fulminant hepatitis: 

Fulminant hepatitis is a rare syndrome created massive necrosis of liver parenchyma tissue and a decrease in liver size.

Fulminant hepatitis is requires urgent medical attention and many necessitate liver transplantation. It’s characterized by rapid and extensive liver cell death, leading to liver failure and encephalopathy.

3.   Chronic hepatitis:

Chronic hepatitis may be silent for years. Symptoms appear only when liver damage is significant. 
Many individuals with chronic HBV infection are asymptomatic and unaware of their infection. Some individuals may experience nonspecific symptoms such as fatigue, mild abdominal discomfort, or intermittent episodes of jaundice. The severity of chronic hepatitis can vary, ranging from mild inflammation to significant liver damage and cirrhosis.

Diagnosis of hepatitis b virus infection

Diagnostic importance of HbsAg test in blood: to detect the exact cause of hepatitis, to screen blood donors, to screen hepatitis b carriers, carriers keep the virus for the rest of their lives and they do not have symptoms and can give it to others. Imaging studies, liver biopsy, liver function tests, and serological tests. 

   What are hepatitis B virus treatment?

• Antiviral therapy

• Monitoring and follow up 

Haw to prevention hepatitis B virus 

The most effective way to prevent hepatitis B virus is to get vaccinated, the secondly you should not share needles at all, practice personal hygiene, do not share towels, tooth brush, ensure donated blood is been properly and practice safe sex.

Conclusion

Hepatitis b remains a global health problem, affecting millions worldwide. While it can cause serious complications like like cirrhosis and liver cancer, early detection, vaccination, and proper treatment greatly reduces risks. Universal immunizations and awareness programs are the most powerful tools in eradicating hepatitis B and protecting future generations.