Instruct: Given a question, retrieve relevant passages that can help answer the question.
Query: Is Hepatitis contagious?
Hepatitis B is a contagious virus that affects the liver, infection can last from a few weeks to a serious lifelong illness. Two different types of infection exist for this disease, "acute" and "chronic." Acute Hepatitis B is a short term illness that occurs within 6 months of exposure, Chronic Hepatitis B is long term and happens when the virus remains in the body.
The younger the child is, the greater their chance of developing a chronic infection and this risk goes down as the child gets older. Approximately 90% of infected infants will develop a chronic infection. 
Since 1990, when the vaccine was introduced as a routine vaccination in children, rates of acute Hepatitis B has decreased in the United States by 82%. This vaccine is given as a series of shots, the first dose is given at birth, the second between 1 and 2 months, and the third, and possibly fourth, between 6 and 18 months. 
Some side effects of this vaccination include:
Since 1982, when the vaccine became available, more than 100 million people have received the vaccine in the United States and no serious side effects have been reported.
Prevention of cancers can be separated into primary, secondary, and tertiary prevention. Primary prevention preemptively reduces exposure to a risk factor for liver cancer. One of the most successful primary liver cancer preventions is vaccination against hepatitis B. Vaccination against the hepatitis C virus is currently unavailable. Other forms of primary prevention are aimed at limiting transmission of these viruses by promoting safe injection practices, screening blood donation products, and screening high-risk asymptomatic individuals. Aflatoxin exposure can be avoided by post-harvest intervention to discourage mold, which has been effective in west Africa. Reducing alcohol abuse, obesity, and diabetes would also reduce rates of liver cancer. Diet control in hemochromatosis could decrease the risk of iron overload, decreasing the risk of cancer.
Two types of HIV have been characterized: HIV-1 and HIV-2. HIV-1 is the virus that was initially discovered and termed both lymphadenopathy associated virus (LAV) and human T-lymphotropic virus 3 (HTLV-III). HIV-1 is more virulent and more infective than HIV-2, and is the cause of the majority of HIV infections globally. The lower infectivity of HIV-2, compared to HIV-1, implies that fewer of those exposed to HIV-2 will be infected per exposure. Due to its relatively poor capacity for transmission, HIV-2 is largely confined to West Africa.
Mumps is spread from person to person through contact with respiratory secretions, such as saliva from an infected person. When an infected person coughs or sneezes, the droplets aerosolize and can enter the eyes, nose, or mouth of another person. Mumps can also be spread by sharing eating utensils or cups. The virus can also survive on surfaces and then be spread after contact in a similar manner. A person infected with mumps is contagious from approximately seven days before the onset of symptoms until about eight days after symptoms start. The incubation period (time until symptoms begin) can be from 12–25 days, but is typically 16–18 days. 20-40 percent of persons infected with the mumps virus do not show symptoms, so it is possible to be infected and spread the virus without knowing it.
Liver disease may present itself as tiredness, increased bleeding tendency or confusion (due to hepatic encephalopathy) and portal hypertension. The latter, a condition in which the pressure in the portal vein is markedly increased, leads to esophageal varices, blood vessels in the esophagus that may bleed in a life-threatening fashion, as well as enlargement of the spleen (splenomegaly) and accumulation of fluid in the abdominal cavity (ascites). On examination, signs of chronic liver disease such as spider angiomata (small distended blood vessels, usually on the chest) may be observed. Chronic active hepatitis has caused cirrhosis of the liver in most by the time they develop symptoms. While most people with cirrhosis have an increased risk of hepatocellular carcinoma (liver cancer), this risk is relatively very low in Wilson's disease.
Transmission is believed to occur most frequently through the shedding of viral particles into saliva. Both HHV-6B and HHV-7 are found in human saliva, the former being at a lower frequency. Studies report varying rates of prevalence of HHV-6 in saliva (between 3–90%), and have also described the salivary glands as an in vivo reservoir for HHV-6. The virus infects the salivary glands, establishes latency, and periodically reactivates to spread infection to other hosts.
Ischemic hepatitis can be caused by a number of reasons (that lead to low blood pressure) including:The mechanism of ischemic hepatitis depends on the etiopathogenetic origin, be it a cardiomyopathy, cardiac tamponade, trauma, or bleeding. Usually ischemic hepatitis reveals itself after a hypotensive event with increased levels of aminotransferases. Because of this, hypotension is thought to be one of the primary insults leading to ischemic hepatitis.
Mumps is a contagious disease caused by the virus by the same name. Since most people in the United States have been vaccinated, mumps is now a rare disease in this country. Currently there are no specific treatments for mumps.
Mumps is spread person to person by droplets of saliva or mucus from the mouth, nose or throat of an infected person. This is done through coughing, sneezing, talking, and coming into contact with contaminate items. Transmission likely occurs before the salivary glands swell an up to 5 days after the swelling begins.
Fifty to seventy percent of cases of gastroenteritis in adults are caused by noroviruses (genus Norovirus, family Caliciviridae). This virus is highly contagious and spreads rapidly. Norovirus is the most common cause of gastroenteritis in the United States.
Leptospirosis is a water contract disease caused by bacteria of the genus Leptospirabacterial. It is a disease that affects both humans and animals. The number of leptospirosis cases had steadily increased from 2011 (2,268 cases with 55 death) to 2015 (8,291 cases with 78 death) and 5,284 cases with 52 death in 2016. Leptospirosis can have important health impact and is a burden to the nation if not well controlled. Addressing leptospisoris includes maintain a clean environment and by not swimming or wading in water that might be contaminated with animal urine, or eliminating contact with potentially infected animals.
At the molecular level, an antigen can be characterized by its ability to bind to an antibody's variable Fab region. Different antibodies have the potential to discriminate among specific epitopes present on the antigen surface. A hapten is a small molecule that changes the structure of an antigenic epitope. In order to induce an immune response, it needs to be attached to a large carrier molecule such as a protein (a complex of peptides). Antigens are usually carried by proteins and polysaccharides, and less frequently, lipids. This includes parts (coats, capsules, cell walls, flagella, fimbriae, and toxins) of bacteria, viruses, and other microorganisms. Lipids and nucleic acids are antigenic only when combined with proteins and polysaccharides. Non-microbial non-self antigens can include pollen, egg white and proteins from transplanted tissues and organs or on the surface of transfused blood cells.
Rotavirus, norovirus, adenovirus, and astrovirus are known to cause viral gastroenteritis. Rotavirus is the most common cause of gastroenteritis in children, and produces similar rates in both the developed and developing world. Viruses cause about 70% of episodes of infectious diarrhea in the pediatric age group. Rotavirus is a less common cause in adults due to acquired immunity. Norovirus is the cause in about 18% of all cases.
Herpes simplex research includes all medical research that attempts to prevent, treat, or cure herpes, as well as fundamental research about the nature of herpes. Examples of particular herpes research include drug development, vaccines and genome editing. HSV-1 and HSV-2 are commonly thought of as oral and genital herpes respectively, but other members in the herpes family include chickenpox (varicella/zoster), cytomegalovirus (CMV), and Epstein-Barr (EBV).
The vaccinations against the following diseases were free and obligatory in Hungary: tuberculosis, diphtheria, tetanus, pertussis, poliomyelitis, haemophilus influenzae, measles, mumps, rubella, hepatitis, streptococcus pneumoniae. The government made vaccinations for other diseases free - chicken pox, the two types of meningitis and rotavirus - in 2018.
Ninety percent of cases of the disease are mild leptospirosis. The rest experience severe disease, which develops during the second stage or occurs as a single progressive illness. The classic form of severe leptospirosis is known as Weil's disease, which is characterized by liver damage (causing jaundice), kidney failure, and bleeding. Additionally, the heart and brain can be affected, meningitis of the outer layer of the brain, encephalitis of brain tissue with same signs and symptoms; and lung affected as the most serious and life-threatening of all leptospirosis complications. The infection is often incorrectly diagnosed due to the nonspecific symptoms.
Human herpesvirus 7 (HHV-7) is one of nine known members of the Herpesviridae family that infects humans. HHV-7 is a member of Betaherpesviridae, a subfamily of the Herpesviridae that also includes HHV-6 and "cytomegalovirus" (HHV-5 or HCMV). HHV-7 often acts together with HHV-6, and the viruses together are sometimes referred to by their genus, "Roseolovirus". HHV-7 was first isolated in 1990 from CD4+ T cells taken from peripheral blood lymphocytes.
Shortage of organ donors make artificial cells key players in alternative therapies for liver failure. The use of artificial cells for hepatocyte transplantation has demonstrated feasibility and efficacy in providing liver function in models of animal liver disease and bioartificial liver devices. Research stemmed off experiments in which the hepatocytes were attached to the surface of a micro-carriers and has evolved into hepatocytes which are encapsulated in a three-dimensional matrix in alginate microdroplets covered by an outer skin of polylysine. A key advantage to this delivery method is the circumvention of immunosuppression therapy for the duration of the treatment. Hepatocyte encapsulations have been proposed for use in a bioartifical liver. The device consists of a cylindrical chamber imbedded with isolated hepatocytes through which patient plasma is circulated extra-corporeally in a type of hemoperfusion. Because microcapsules have a high surface area to volume ratio, they provide large surface for substrate diffusion and can accommodate a large number of hepatocytes. Treatment to induced liver failure mice showed a significant increase in the rate of survival. Artificial liver systems are still in early development but show potential for patients waiting for organ transplant or while a patient's own liver regenerates sufficiently to resume normal function. So far, clinical trials using artificial liver systems and hepatocyte transplantation in end-stage liver diseases have shown improvement of health markers but have not yet improved survival. The short longevity and aggregation of artificial hepatocytes after transplantation are the main obstacles encountered.
Hepatocytes co-encapsulated with stem cells show greater viability in culture and after implantation and implantation of artificial stem cells alone have also shown liver regeneration. As such interest has arisen in the use of stem cells for encapsulation in regenerative medicine.
There are many causes of infectious diarrhea, which include viruses, bacteria and parasites. Infectious diarrhea is frequently referred to as gastroenteritis. Norovirus is the most common cause of viral diarrhea in adults, but rotavirus is the most common cause in children under five years old. Adenovirus types 40 and 41, and astroviruses cause a significant number of infections. Shiga-toxin producing Escherichia coli, such as , are the most common cause of infectious bloody diarrhea in the United States.
Humans become infected through contact with water, food, or soil that contains urine from these infected animals. This may happen by swallowing contaminated food or water or through skin contact. The disease is not known to spread between humans, and bacterial dissemination in convalescence is extremely rare in humans. Leptospirosis is common among water-sport enthusiasts in specific areas, as prolonged immersion in water promotes the entry of this bacterium. Surfers and whitewater paddlers are at especially high risk in areas that have been shown to contain these bacteria, and can contract the disease by swallowing contaminated water, splashing contaminated water into their eyes or nose, or exposing open wounds to infected water.
In tropical and semi tropical areas, like South and South-east Asia the disease is increasingly seen as epidemics after heavy rains, sometimes after flooding. Periods of heavy rain followed by days of little or no rain seemed to be the setting for leptospirosis epidemics in this part of the world. Most cases seemed to occur by cutaneous exposure of the legs while walking in stagnant water or moist soil. The presence of wounds or fissures on the legs are a risk factor for acquiring the infection.
Condoms offer moderate protection against HSV-2 in both men and women, with consistent condom users having a 30%-lower risk of HSV-2 acquisition compared with those who never use condoms. A female condom can provide greater protection than the male condom, as it covers the labia. The virus cannot pass through a synthetic condom, but a male condom's effectiveness is limited because herpes ulcers may appear on areas not covered by it. Neither type of condom prevents contact with the scrotum, anus, buttocks, or upper thighs, areas that may come in contact with ulcers or genital secretions during sexual activity. Protection against herpes simplex depends on the site of the ulcer; therefore, if ulcers appear on areas not covered by condoms, abstaining from sexual activity until the ulcers are fully healed is one way to limit risk of transmission. The risk is not eliminated, however, as viral shedding capable of transmitting infection may still occur while the infected partner is asymptomatic. The use of condoms or dental dams also limits the transmission of herpes from the genitals of one partner to the mouth of the other (or "vice versa") during oral sex. When one partner has a herpes simplex infection and the other does not, the use of antiviral medication, such as valaciclovir, in conjunction with a condom, further decreases the chances of transmission to the uninfected partner. Topical microbicides that contain chemicals that directly inactivate the virus and block viral entry are being investigated.
The Answer to Cancer (A2C) run was founded by Adrian Elkins, a 20-year-old student at Southern Oregon University who was diagnosed with liver cancer in 2002. Had he known during his childhood that his ethnicity and chronic hepatitis B infection increased his chance of developing liver cancer by 100%, he would have been regularly monitored for liver damage. He had no idea that hepatitis B—a disease he contracted at birth in Calcutta, India—causes 80% of the world's liver cancer cases. Adrian battled his disease for ten months, working tirelessly to organize an event to raise money for liver cancer research. Adrian saw the first-ever A2C run take place on 8 August 2003. Thanks to the generous support of friends, families and numerous companies, the 2003 Answer to Cancer Race was able to raise more than $20,000 for three charities and reach out to more than 240 participants. Adrian died only eight days after this first race.
Hepatitis C virus (HCV) genotypes refer to the genetic variations that occurs in the hepatitis C virus. Hepatitis C is a contagious disease that primarily affects the liver, causing severe damage as the disease progresses. It is caused by the Hepatitis C virus, a small, enveloped RNA virus. The transmission of hepatitis C is through the contact with the blood of the infected person,for example by sharing the needles or by using non-sterile medical equipment. HCV is transmitted globally because of the high infection rate and is also associated with a high mortality rate. The World Health Organisation indicates the 3.3% of the world population is infected by the HCV virus. Statistical records show that there are about 13 million HCV affected persons in china, 3.5 million affected persons in the United States, and about 10 million people are affected by HCV in Pakistan. In all cases, the viral genotype of the HCV stays the same, occasionally mutations do occur making the treatment more complex by targeting the changes in the genotype. Hepatitis C virus genotype is considered more common than the Hepatitis B virus infection contributing to more than a million cases annually and is considered one of the major reason for liver transplantation in United States. Some of the HCV genotypes may develop in people without symptoms leading to dangerous conditions like liver cirrhosis causing a permanent damage to liver and the unnoticed HCV conditions will affect brain, joints, blood vessels, bones, and kidneys.
The disease is restricted to turkeys and is highly contagious but usually subclinical. It usually present in young birds under the age of 6 weeks.
Fulminant hepatitis, or massive hepatic cell death, is a rare and life-threatening complication of acute hepatitis that can occur in cases of hepatitis B, D, and E, in addition to drug-induced and autoimmune hepatitis. The complication more frequently occurs in instances of hepatitis B and D co-infection at a rate of 2–20% and in pregnant women with hepatitis E at rate of 15–20% of cases. In addition to the signs of acute hepatitis, people can also demonstrate signs of coagulopathy (abnormal coagulation studies with easy bruising and bleeding) and encephalopathy (confusion, disorientation, and sleepiness). Mortality due to fulminant hepatitis is typically the result of various complications including cerebral edema, gastrointestinal bleeding, sepsis, respiratory failure, or kidney failure.
Excessive alcohol consumption is a significant cause of hepatitis and is the most common cause of cirrhosis in the U.S. Alcoholic hepatitis is within the spectrum of alcoholic liver disease. This ranges in order of severity and reversibility from alcoholic steatosis (least severe, most reversible), alcoholic hepatitis, cirrhosis, and liver cancer (most severe, least reversible). Hepatitis usually develops over years-long exposure to alcohol, occurring in 10 to 20% of alcoholics. The most important risk factors for the development of alcoholic hepatitis are quantity and duration of alcohol intake. Long-term alcohol intake in excess of 80 grams of alcohol a day in men and 40 grams a day in women is associated with development of alcoholic hepatitis (1 beer or 4 ounces of wine is equivalent to 12g of alcohol). Alcoholic hepatitis can vary from asymptomatic hepatomegaly (enlarged liver) to symptoms of acute or chronic hepatitis to liver failure.