Hepatitis is categorized into five distinct types: hepatitis A, B, C, D, and E. These variations of hepatitis are all viral infections that mainly affect the liver causing various symptoms from fever to liver cancer.
Table of Contents
Hepatitis A
Distribution
Countries that have poor hygiene and poor sanitary conditions have the highest instances of infection with 90 percent of children being infected with the hepatitis A virus before they are 10 years old.2 These countries are undeveloped areas in Africa, and Asia. Individuals that were infected with hepatitis A while they were children usually do not display any symptoms accompanying infections or in other words they are asymptomatic.2 Outbreaks tend to be rare due to the large fraction of the population having previously been infected and building immunity.2
Intermediate levels of infection are found in countries where sanitary conditions vary from area to area.2 Countries that are described qualitatively as having intermediate levels of infection are developing countries.2 Children in these countries tend to evade infection but by doing so without also receiving the vaccine they do not gain immunity.2 In these communities older age groups are more susceptible to higher rates of these viral infections because the improved sanitary conditions combined with a lack of vaccination leads to adults that have no immunity.2
In countries with good sanitary and hygiene practices, the rate of infection is very low unless an individual engaged in high risk activities, including, males having sex with males, intravenous drug use, and traveling to areas with high endemicity.2
Symptoms
The incubation period for hepatitis A is 2- 4 weeks and the symptoms of hepatitis A are usually flu-like, including headache, nausea, fatigue, fever, stomach pains, and jaundice (a yellowing of the skin and eyes).1 Diarrhea can be a dangerous symptom of hepatitis A in areas where water is hard to come by. In some cases, a person may not notice any symptoms. The symptoms are usually detected anywhere from 2 to 7 weeks after being exposed to the hepatitis A virus. The symptoms only last about 2 months.2 It is more common for adults to show severe symptoms rather than children with jaundice occurring in more than 70 percent of cases in adults compared to 10 percent of cases in children.2 Hepatitis A is rarely fatal and does not cause chronic liver disease, but can cause acute liver failure. Hepatitis A is normally diagnosed from the detection of HAV- specific Immunoglobulin G (IgM) antibodies in the patient’s blood.2
Transmission
The hepatitis A virus is found in the feces of an infected person. It is most commonly spread when eating food that has been in contact with fecal matter, for example, food that has been prepared by people who did not wash their hands after using the bathroom.2 Hepatitis A spreads easily in areas with poor sanitation and hygiene such as developing countries with unsafe water.1 The virus can also be spread sexually through oral-anal contact, such as performing analingus or oral sex with an object that has been in contact with the anus.
Treatment
Medical treatment for hepatitis A is usually not necessary, because in most cases, the disease goes away on its own. It is advised to get bed rest, keep hydrated with fluids, and not consume alcohol if one has contracted hepatitis A. It is highly advised that unnecessary medications like Acetaminophen and anti- nausea medications should be avoided as this could further damage the liver.1 Typically, the immune system develops antibodies against the virus, which should protect the person from any future infections. Nevertheless, it is wise to see a doctor for professional advice if one becomes infected.
Prevention
Hepatitis A is easily preventable by using the vaccine that has been developed for it.3 Unfortunately some of the areas that are most affected by this disease do not have easy access to the vaccine and rates of vaccination remain low.3 Common risk factors for contracting the hepatitis A virus are IV drug use, living in an area with poor sanitation, lack of safe water, living with a person with the virus, having a sexual partner who has a hepatitis A infection, traveling to places where hepatitis A is prevalent without being immunized, and being a person with chronic liver disease.2 The possibility of hepatitis A being spread can be diminished by having enough safe drinking water, disposing of sewage from communities properly, and by practicing good personal hygiene including hand washing with clean water.2 Immunization efforts are underway all over the globe with goals of raising awareness, preventing transmission, and increasing treatment services.2
Hepatitis B
Distribution
This life threatening liver infection is considered a major health problem due to its ability to cause chronic infection, and death from cirrhosis and liver cancer. Hepatitis B is most prevalent in sub- Saharan Africa, East Asia, the Amazon, and southern parts of eastern and central Europe. In these areas about 5 to 10 percent of the adult population is infected. North America, Western Europe, and The Middle East have a lower infection rate around 1 to 5 percent.2
Symptoms
The symptoms of hepatitis B are similar to those of hepatitis A. They can include jaundice, fever, stomach pains, persistent fatigue, light-colored stool, and nausea. The symptoms appear between 1 and 6 months after exposure to the virus. It is important to note that many people do not experience any symptoms when they have hepatitis B, and may unknowingly pass it to others. The hepatitis B virus may cause chronic liver infection which can lead an infected individual to develop cirrhosis of the liver as well as liver cancer.2
Transmission
The hepatitis B virus is found in bodily fluids, such as blood, semen, vaginal secretions, and saliva. The virus can be spread through sexual activities in which one comes in contact with infected bodily fluids. An infected pregnant woman can also transmit hepatitis B to her child at the time of childbirth. Perinatal transmission is an extremely common way to spread the virus as well as horizontal transmission (infected blood transmission) and from one infected child to a child under the age of 5. It is important to know that the hepatitis B virus can survive outside of a host for 7 days or more and in this time the virus is still fully capable infecting another person if they are unvaccinated. The virus can be spread through tattooing, razors, needles, or any other objects that may have come in contact with a hepatitis B carrier’s blood.2
Treatment
When hepatitis B cases are diagnosed shortly after exposure, the doctor will usually give the patient a hepatitis B vaccine, which should help the immune system fight the disease quickly. For chronic hepatitis B cases that continue past 6 months, treatment usually consists of a combination of certain medications. Most people with hepatitis B are able to fight off the disease and build up antibodies that protect them from any future infection of the virus. However, some people may continue to carry the virus and pass it on to others, even when their symptoms have disappeared. The most chronic cases of hepatitis B would be treated with antiviral drugs such as tenofovir or entecavir which are the most potent drugs against the hepatitis B virus. Unfortunately most infected individuals can not be cured of hepatitis B so they must be treated for it their entire lives. Interferon injections as treatment are common in high- income communities but are unrealistic in low- income areas where resources are highly limited. In these limited resource areas many patients get diagnosed too late and have already developed liver cancer which progresses quickly. These patients will most likely lose their lives within month of diagnosis. High- income areas have the luxury of access to chemotherapy and possible transplantation as ways of prolonging life.
Molecular Structure of antiviral drug Tenofovir
Prevention
The best way to prevent hepatitis B is to get vaccinated.3 Unfortunately, the rate of vaccination for hepatitis B is still low in the areas that need vaccination the most including those with chronic liver disease.3 Also, it is extremely important to use condoms or other barrier methods when engaging in sexual activities, in order to avoid contact with infected fluids. It is also wise to avoid any contact with blood, such as from an open wound, razor, pierced earrings, needles, etc. People should avoid exchanging saliva by not sharing chewed food, gum, or toothbrushes.2 According to the WHO all infants should receive the hepatitis B vaccine within 24 hours after birth. The WHO reports that “As of 2014, 184 Member States vaccinate infants against hepatitis B as part of their vaccination schedules and 82% of children in these states received the hepatitis B vaccine.”
Hepatitis C
Distribution
Globally 130-150 million people experience chronic hepatitis C infection. This viral infection is most commonly found in Africa, Central and East Asia. 700,000 people a year die due to hepatitis C related liver complications. To make matters, there is still not vaccine for hepatitis C with research into a possible vaccine currently underway. hepatitis C is one of the leading causes of cirrhosis and hepatocellular carcinoma (liver cancer) in the world.5
Symptoms
Many people who are infected with hepatitis C do not even know they have it because they do not experience any symptoms. When people do experience symptoms, they can include jaundice, fatigue, discolored urine, sore muscles, joint pain, and stomach pain. When people are newly infected with the virus, they may experience acute hepatitis C. Once people have had the disease for over 6 months, they are said to have chronic hepatitis C. Often times, people may have chronic hepatitis C for a while before it is diagnosed, which is usually by accident.3
Transmission
Hepatitis C is spread when an infected person’s blood comes in contact with the blood of a second person. Most commonly, this happens when people share injection needles with infected people, as when using needles to take illegal drugs. Sometimes, an infected mother can pass hepatitis C to her child at the time of birth. The chances of contracting hepatitis C through sexual activity are low, since this would have to somehow allow blood-to-blood contact. Hepatitis C can also be transmitted through insufficiently sterilized medical equipment and blood transfusions of improperly screened blood.3
Treatment
Unfortunately by the time that most people are diagnosed with hepatitis C, it has developed into a chronic, long-term disease that they have to live with throughout the remainder of their lives. Hepatitis C can cause severe liver damage and even liver failure.6 There are antiviral medications available to prevent the virus from damaging the liver. New antiviral drugs called direct antiviral drugs (DAA) are being used and are much more effective, and safer. These new antiviral drugs can cure most hepatitis C infected persons compared to the older treatment of 48 weeks of weekly injections of interferon and ribavirin that only cured half of patients and caused dangerous reactions.3
Prevention
Unlike hepatitis A and B, there is no vaccine for hepatitis C. There are, however, other steps that one can take to help prevent contracting hepatitis C. Do not share injections needles with anyone or use needles that are not completely sterilized. People who work with blood or needles in a medical profession should always wear gloves to protect themselves. Also, people who are getting a piercing or tattoo, make sure that all the instruments are sterilized. The WHO recommends excellent surgical hygiene, safe handling of sharps,waste, and testing of donated blood for hepatitis B, and C as well as HIV and syphilis, training of health personnel, and promotion of condom use.
Hepatitis D
Distribution
Hepatitis D is a special type of hepatitis in the fact that it is a ribonucleic acid (RNA) virus and it requires hepatitis B in order for it to replicate.7 This means that hepatitis D infection can only occur if it is a super- infection with hepatitis B. An estimated 5% of hepatitis B virus positive people are infected with hepatitis D as well.7 Hepatitis D is most commonly found in Northern Asia, Japan, Taiwan, Greenland, parts of Africa, the Mediterranean, the Middle East, Pakistan, the Amazon Basin.7
Symptoms
The symptoms of hepatitis D are the same as hepatitis B but it reduces the replication of hepatitis B. Superinfection of the hepatitis D virus causes chronic hepatitis B progression to become more severe in all ages and 70% – 90% of people infected with hepatitis B. Cirrhosis occurs almost a decade before it normally would in people who are not simultaneously infected.7
Transmission, Prevention, and Treatment
Transmission in hepatitis D is the same as hepatitis B: spread through contact with infected blood or through sex with someone who is infected with virus where blood can be exchanged.7 The best way to prevent the transmission of hepatitis D is to get the vaccination for hepatitis B because without the hepatitis B infection the hepatitis D virus will be unable to replicate and incapable of causing any damage.7 High risk factors for the spread of hepatitis D include being an injectable drug user, and going to areas where hepatitis D and B are endemic.7 There is one known effective drug against hepatitis D replication which is pegylated interferon alpha.7
Hepatitis E
Distribution
Hepatitis E is spread throughout the world in areas with frequent water contamination and surprisingly places with safe drinking water.8 In areas with unclean water, the disease spreads during outbreaks and cases that suddenly occur.8 Contamination of drinking water by feces is how outbreaks usually occur infecting several thousands of people.8 These contaminations can be found commonly in war zones, refugee camps, and humanitarian emergency areas where
clean water is hard to find and the water supplies are subject to high probabilities of mixing with human waste.8 Hepatitis E has been found to be responsible for about 56,600 deaths in 2010.9 Hepatitis E has an estimated 20 million infections across the globe and 3.3 million cases where the infected are symptomatic.10 There are at least 4 different genotypes for the virus which is a single-stranded ribonucleic acid (RNA) virus.8 Genotypes 1 and 2 have only ever been found to infect humans while genotypes 3 and 4 are usually transmitted in animals and can infect humans but not to the degree of 1 and 2.10 In areas with good sanitation and clean water supplies genotype 3 is normally the cause of infection from being transmitted by undercooked animal meat.8
Symptoms
The incubation period after exposure to hepatitis E is from 2 to 10 weeks with an average of about 5 to 6 weeks. Hepatitis E presents with a mild fever, vomiting and nausea, as well as reduced appetite.8 Patients with the disease may also present with abdominal pain, joint pain, skin rash, and skin itching.8 Dark urine and pale stools are more symptoms as well as jaundice and hepatomegaly (enlarged, tender liver).8 This symptoms normally last from 1 to 6 weeks and hepatitis E appears similar to many other liver diseases.8 Liver failure can occur in some rare cases with fatality rates at high as 20-25% for pregnant women in their third trimester.8 For nonpregnant cases the probability of death given symptomatic illness was 0.019 with 95% certainty.10
Transmission
Hepatitis E is transmitted similarly to the other viruses in that it is spread through the fecal- oral route in food or drinking water.11 Hepatitis E can be spread by undercooked meat, transfusion of infected blood, and transmission from a pregnant woman to her fetus called vertical transmission.8
Treatment
Hepatitis E must run its course because there is no treatment and the disease usually is self- limiting before it gets to the point of becoming a chronic disease.11 People with suppressed immune systems are treated using ribavirin and sometimes interferon has been used successfully.8
Prevention
The best way to prevent the spread of hepatitis E is to keep public water supplies clean as well as properly getting rid of human waste to prevent contamination of populations that could be susceptible to infection by hepatitis E.8 Individuals can reduce their risk of contracting hepatitis E by adhering to safe hygiene practices like washing their hands with clean water and when handling food.8 In 2011 a vaccine designed to prevent hepatitis E infection was developed in China but has not been legalized in other countries.8
References
- Demiray, T., M. Koroglu, K.H. Jacobsen, A. Ozbek, H.A Terzi, and M. Altindis. “Hepatitis A Virus Epidemiology in Turkey as Childhood Vaccination Begins: Seroprevalence and Endemicity by Region.” Journal of Clinical Virology. Elsevier, Web.
- “Hepatitis A.” World Health Organization. World Health Organization, July 2016. Web.
- Koenig, Aaron, Maria Stepanova, Sean Felix, Shirley Kalwaney, Stephen Clement, and Zobair M. Younossi. “Vaccination against Hepatitis A and B in Patients with Chronic Liver Disease and Type 2 Diabetes: Has Anything Changed?” Onlinelibrary.wiley. John Wiley & Sons, Inc, 2 June 2016. Web.
- “Hepatitis B.” World Health Organization. World Health Organization, July 2016. Web.
- “Hepatitis C.” World Health Organization. World Health Organization, July 2016. Web.
- Li, Ying, Xiao-hui Li, Zai-xin Yu, Jing-jing Cai, Timothy R. Billiar, Alex F. Chen, Ben Lv, Ziying Chen, Zhi-jun Huang, Guo-ping Yang, Jie Song, Bin Liu, and Hong Yuan. “HIV Protease Inhibitors in Pulmonary Hypertension: Rationale and Design of a Pilot Trial in Idiopathic Pulmonary Arterial Hypertension.” The University of Chicago Press Journals. Pulmonary Vascular Research Institute, Sept. 2015. Web.
- “Hepatitis D.” World Health Organization. World Health Organization, July 2016. Web.
- “Hepatitis E.” World Health Organization. World Health Organization, July 2016. Web.
- Prof Rafael Lozano, MD, Mohsen Naghavi, PhD, Kyle Foreman, MPH et. al.”Global and Regional Mortality from 235 Causes of Death for 20 Age Groups in 1990 and 2010: A Systematic Analysis for the Global Burden of Disease Study 2010.” The Lancet. Elsevier, 15 Dec. 2012. Web.
- Rein DB1, Stevens GA, Theaker J, Wittenborn JS, Wiersma ST. “The Global Burden of Hepatitis E Virus Genotypes 1 and 2 in 2005.” National Center for Biotechnology Information. U.S. National Library of Medicine, Apr. 2012. Web.
- V, Mallet, Sberro-Soussan R, Vallet-Pichard A, Roque-Afonso AM, and Pol S. “Transmission of Hepatitis E Virus by Plasma Exchange: A Case Report.” – Abstract. Europe PMC, 21 June 2016. Web.
Last Updated: 31 October 2016.