Hepatitis B Virus In Saudi Arabia Biology Essay

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During a specific time of the year about 2 million come to the cities of Mecca and Medina in Saudi Arabia to do pilgrimage called Hajj. As there is a large gathering of people there will be problems and many people will end up becoming sick. Hepatitis B virus is an endemic in this region especially during this time of the year. Being in a close compound with people who don't practice safe sanitation of cleaning or reusing tools can lead to hepatitis B virus. During Hajj the males have to shave their heads marking the end of the pilgrimage, and some barbers end up using the same blade which can lead to HBV infection in both barbers that male. If the blades are thrown away people can also step on it without knowing the risk. Knowing the structure of hepatitis B virus, their transformation, how it is infects people, and treatment of hepatitis B we can prevent from spreading to people and reducing the chance of it causing deaths.

Hepatitis B virus is in the family Hepadnaviridae and genus Orthohepadnavirus (Shors 2009). This virus structure is unique because rather than being just single stranded or double stranded DNA it actually a partially double stranded DNA with a circular genome. This virus has 8 genotypes (A-H) which are different strains that are specifically present in that region of the world (Rafiq et.al 2003). The DNA has about 3200 base pairs that encodes for 4 overlapping open reading frames; S, for the envelope, gene; C, for the core gene; X for the X gene; and P, for the polymerase gene (Williams). These genes are also referred as genomic pre-S1, S, and X promoters. HBV has a spherical shape with icoshaedral capsid symmetry with a 42-nm sphere that contains a nucelocapsid (Williams). The envelope is surrounded by an outer lipoprotein coat that contains the antigen HBsAg. There are several types of antigens that are part of hepatitis B virus. One of them is the HBsAg that provides that basis for HBV vaccines that are currently available to us. This antigen is produced excessively during the life cycle of the virus. The core antigen of Hepatitis B (HBcAg) is the nuleocapsid that surrounds the viral DNA (Williams). Once this antigen is expressed on the surface of hepatocytes they will induce a cellular response that are important in killing infected cells (Williams). Derived from the core gene hepatitis B e antigen (HBeAg) is modified and exported from the liver cells which will be the marker for the liver cell during the active viral replication (Williams). This antigen is only present in people who have circulating serum HBV DNA (Williams). Not only is HBV unique for having a partial double stranded DNA but it also has reverse transcriptase. The P gene in the virus will encode for DNA polymerase which in return serve has a reverse-transcriptase function, since the virus needs RNA intermediate for replication (Williams). The X gene encodes for two proteins that aid in viral replication using transcriptional transactivator.

As previously discuss the life cycle of HBV is very unique. Hepatitis B enters the bloodstream where they are transferred to the liver and infect the hepatocytes of the liver (Shors). They will replicate in the liver and the hepatocyte may seriously be damaged causing cirrhosis, and malfunction of the liver (Shors). They liver is used in many different functions such as producing bile, metabolism, filtering toxins and waste products in the blood (Shors). If this is not working properly our body can slowly start to shut down. To replicate first, HBV needs to bind to a receptor at the surface of the hepatocyte to enter the cell by using the endocytosis process. The endocytosis process is where the cell is engulfed by the molecule (Shors). There are many different receptors that HBV can bind such as transferring receptor, asialolycoprotein receptor molecule, and human liver endonexin (Shors). There is still no information if HBsAg can bind to a specific receptor to enter the cell. Once it enters the cell it will release the mRNA and core proteins into the cytoplasm, but since it needs multiply by RNA the DNA needs to be transferred to the nucleus for synthesis to be completed (Shors). Once the second-strand DNA synthesis is completed in the nucleus and their gaps are repaired, the partially double stranded DNA is made into a fully double stranded DNA and into a covalently closed circular (ccc) supercoiled DNA called episome ("Hepatitis B virus", Shors). The episomes will be used as template for transcription of four viral RNAs whose size ranges from .7-3.5 kb ("Hepatitis B virus", Shors). The episome is able to replicate by itself in the host chromosome rather than being integrated into the cellular DNA, since it is a retrovirus, and HBV does not have integrase activity (Shors). There will be two transcripts where the episome will act as the template, the pregenomic RNA transcript and genomic RNAs that are transcribed by the host RNAs polymerase II (Shors). HBV DNA is very compacted in coding organization that has four partially open reading frames (ORFs) and is translated into seven proteins. The fours ORFs are S, C, P, X which have different gene products. In transcription factors it has been identified that there are at least four promoters, two enhancers, and several binding sites (Shors). The pregenomic RNA which is positive single stranded, it is synthesized and put together with viral polymerase and protein kinase C protein into core particles ("Hepatitis B virus", Shors). The viral reverse transcriptase is heat shocked by the host cell proteins which will allow it to go under active conformation. The reverse transcriptase will convert the pregenomic RNA into DNA inside the particles (Shors). Reverse transcriptase cannot happen without protein-priming, unlike other retroviruses that uses RNA -priming (Shors). Replication cannot occur unless it is in its own specific environment. Once the replication occurs the nucleocapsid cores reaches the endoplasmic reticulum (ER) where they assemble with the envelope proteins and bud into the lumen of the ER ("Hepatitis B virus"). From there they are secreted by the Golgi apparatus and out of the cell. The empty envelope that contains the viral surface proteins that are in the host cell's lipid bilayer are continually being shed along the mature infectious particles (Shors).

Of more than 2 billion people infected with HBV most of them develop anti HBs antibody and do well throughout their life, but chronic hepatitis B does infect approximately 350 million people worldwide. There are more than 4 million people who are shown to have acute clinical cases and more than 1 million of chronic carriers die from liver disease (Rafiq et.al). HBV can be contracted very early in life which can lead to chronic hepatitis, then cirrhosis of the liver, from cirrhosis it leads to hepatocellular carcinoma (HCC), then death from liver failure. Chronic hepatitis B occurs in 5% to 10% of people after the age of 5. This process can take up to 30 to 50 years. Incubation for hepatitis B is 80 days, and 30% of the individuals don't show any signs or symptoms of the disease (Shors). HBV does not cause direct cell injury, but the immune response of both cellular and humoral determines the course of infection (Williams). Study has shown that humoral immuntiry does not play a role in clearance of HBV infection. It is shown that cell-mediated immune response such as cytotoxic T lymphocytes are very important (Williams). Cytotoxic T lymphocytes recognize hepatitis B which leads to destruction of infected hepatocytes with an increase of CD4+ cellular response (Williams). If a patient is receiving an immunosuppressive therapy the infection can go out of control, replication is exaggerated and direct CPE is produced (Williams). The symptoms that are shown once your are infected with HBV are jaundice (yellowing of the skin), dark urine, extreme fatigue, nausea, vomiting, abdominal pain (WHO). It also causes chronic liver infection that later develops into cirrhosis of the liver or liver cancer, ultimately leading to death (WHO).

The best prevention of HBV is the Hepatitis B vaccination. Newborns are required to be vaccinated at birth (WHO).The pilgrims who are coming to Hajj are advised to get vaccinated 6 months prior to Hajj. Hepatitis B immune globulin (HBIG) vaccination helps if it is given before or soon after the exposure of HBV. This is also given to newborns with combination of HBV vaccines whose mothers are HBsAg positive ("Hepatitis B"). If we can prevent transmission of HBV between a mother and a newborn it will reduce the newborn's chance of developing chronic liver disease children who are less the 5 years old. With 90% coverage of infant hepatitis B vaccination, and the first dose given to newborns at birth it would prevent most HBV infection, and reduce the global HBV-related deaths to 84% (Rafiq et.al). If the travelers were given different amount doses of the vaccination they have a likely chance that they won't contract HBV. If you are going to Hajj in Saudi Arabia an accelerated schedule of dosage is available last minute from 0,7, 21 days (Rafiq et.al). It is a real threat that these barbers need to license and have hygienic shaving practices. Testing was done on 158 barbers for hepatitis and it showed that 4% were positive for hepatitis B antigen (HBsAg) and .6% for hepatitis B surface antigen (Ziad et.al). It was shown that educating the Hajj pilgrims and also the barbers before Hajj can lead to promising results. Saudi Arabia now has tighter control on barbers and their safe disposal of razor blades and shaving waste during this time (Rafiq et.al). With active public campaign there can be dramatic reduction of HBV in Saudi Arabia especially during the time for Hajj (Ziad et.al). Having good hygiene and being cautious while handling human blood or body fluids can help reduce the transmission of hepatitis B virus. Without vaccination or taking precautions while handling fluids, transmission can occur between humans and hepatitis B can be spread to everyone, which later on in life can lead to death ((Ziad et.al).. With all the vaccination there is still no specific treatment for acute viral hepatitis B disease, so there aren't any antibiotics that are available for the infection. Antiviral drugs such as lamivudine are available but they have not been tested for the treatment of the infection. The therapeutic way to treat acute hepatitis B is to aim for comfort and balance of nutritional diet ("Hepatitis B virus").

The high risk groups for HBV are infants who are born to infected mothers, health care workers, close gathering of children who associate with other children in HBV endemic areas such as Saudi Arabia. Sexually active people, drug users who use unsterilized injection or needles, people who provide or receive acupuncture or tattoos with unsterilized medical tools, patients and employees in haemodialysis centers, and immunecompromised individuals ("Hepatitis B virus"). People who are frequently exposed to blood or serum are at risk at being exposed to HBV since they deal with blood and other body fluids ("Hepatitis B virus"). Careful screening is done when blood transfusion is taken place because some people don't show symptoms or sign of HBV after being infected. Trying to vaccinate the people in the major risk group is hard to do when you cannot identify the candidates who belong in those groups. Plus it takes a lot of time and money to implement these vaccination programs ("Hepatitis B virus"). It is encouraged that high risk person be tested within 1-2 months after receiving the third dose of HBV vaccine to see if they respond well to the vaccination (Hepatitis B). Prevalence for hepatitis B varies from each geographical region. There is 8% prevalence in Far East, parts of the Middle East, sub-Saharan Africa. The mass travel and migration keeps changing the epidemiology of HBV vaccine making it harder to introduce the hepatitis B vaccine (Rafiq et.al).

It is estimated the 600,000 people die from acute or chronic HBV (WHO). HBV is also 50 to 100 times for infectious then HIV (WHO). Overall, HBV is an interesting virus because not only is it a retrovirus, but it acts independently compared to other retrovirus. It also has to goes through reverse transcriptase while trying to replicate into the cell. Taking precautions before going to Hajj in Saudi Arabia can reduce your chance of receiving HBV infection. Taking vaccination before going to Saudi Arabia and making sure your barber uses clean blades on you can help him and yourself by reducing your chance of contracting the disease. Saudi Arabia is still a developing country, but they are educating their travelers to practice clean hygiene while doing pilgrimage for Hajj. HBV cannot be detected, and the only way to be sure you have it to take your require doses of the vaccine to see how you respond to the drugs. For acute hepatitis B virus there aren't any vaccine or treatment available, but maintaining a healthy lifestyle and prolong the disease.

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