This form of the hepatitis is the most common in occurrence and is also considered the least dangerous form of the condition; this is the first form of the virus which was identified as the causative pathogen for hepatitis. The virus that causes hepatitis A is a food borne virus, resembling the poliovirus closely and structurally with just one bare strand of RNA enclosed inside a 20-sided shell. The virus can replicate itself only within the cells of the liver after it has infected a person. It is mainly contracted from food or water contaminated with feces and it infects only humans and a few closely related primates. This form of the hepatitis virus was formerly known as the "infectious hepatitis". The hepatitis A virus is fairly common in occurrence. The viral infection seems to occur in epidemiological cycles though there is no typical "season" for hepatitis A infection. The demographic group most likely to be affected by the illness includes school-age children and young adults and the disease is considered a disease contracted from poor hygienic practices and dirty places. Thus the prevalence of this form of the hepatitis infection in overcrowded areas in many developed countries and in the majority of developing countries is around 90 percent or more. Many 10 year old children become healthy carriers of the virus and are thus immune as adults even though infected. Immunity from the infection is estimated at 40 percent among all healthy adults in the United States. This immunity is a direct result of previous infection during childhood and all such individuals have an immunity that lasts for life. The condition has been known since ancient times and records of the symptoms of infection from the virus exist from 400 B.C., when it is believed to have afflicted armies in almost every war. The infection resulting from this form of hepatitis is believed to have a role in Napoleon's defeat in the wars of the 19th century. Hepatitis A has also been known variously as the epidemic hepatitis or epidemic jaundice, the catarrhal jaundice, the infectious icterus, Botkins disease and MS-1 hepatitis at various times and different places. Viruses are separated into different classes or groups, and the hepatitis A virus is included in the ENTEROVIRUS GROUP of the picornaviruses, other viruses in this group include the poliovirus which causes polio, the COXSACKIEVIRUS, the ECHOVIRUS, and the RHINOVIRUS. The transmission of the hepatitis A is thus through contamination of spread food or drinking water with the hepatitis A virus or (HAV) in short, this virus passes into the stool and once such stools contaminate water or food - they pass along viral particles which infect the new host. The hepatitis A virus thus gains entry into the body via the mouth, once it enters the body it begin to multiply at a very speedy rate, some of these viral particles are of course passed off again in the feces - thus repeating the cycle. Normally once the virus is in the feces, the viral particles can be carried or passed on to the person's hands and from there it can spread by direct contact, such unclean hands on a person handling food and drinks for others may spread the virus. The hepatitis A virus can affect any person; however, children are the most likely demographic group to be affected by the condition. Transmission of the condition is through close personal contact between family members for the majority of patients, and from sexual partners - particularly with regard to homosexual men, and the disease is also easily contracted in areas such as nursery schools and child care centers. The virus that causes hepatitis A is very resistant and spreads around very easily. The virus is adapted to staying active for more than a month at room temperature on places such as kitchen countertops, on the surface of children's toys, and on other surfaces-this is in great contrast to other viruses which perish very quickly. When kept in frozen foods and ice, the virus can be maintained viable for an indefinite period of time. All food preparations and dishes must be heated up to 185 degrees F for a minute so as to inactivate the virus and prevent infection. The disease can easily be transmitted by contaminated the hands of a food handler or a food server who has hepatitis A - this is especially true if he or she touches the food eaten raw-example are sandwiches or salads. Hepatitis A is also known to be abundant in well water, especially water, that has been contaminated by improperly treated or raw sewage - this is very relevant as the hepatitis A virus is known to exist for a long time in water and in damp places. The presence of hepatitis A in water is very difficult to detect even when using very high quality techniques. Those not at risk from infection through contaminated water include all individuals who use treated municipal or those who use water sourced from the county water supplies. The consumption of raw or undercooked foods, example-shellfish, especially oysters can cause hepatitis A, if these have been raised in water contaminated by the virus. Water contaminated with the hepatitis A virus can infect shellfish and the virus can concentrate in the shellfish because shellfish filter large amounts of water at any given time-eating such foods will almost certainly lead to infection. This is illustrated by a real life example that occurred in Florida in 1988, when 61 people who ate raw oysters illegally taken from contaminated waters came down with the hepatitis A. eating raw shellfish remains as a minor risk factor for contracting hepatitis A, even if the shellfish is sourced from area under federal water quality regulations and the posting of contaminated water notices, may offer some protection. No obvious symptoms of the disease are apparent in at least a quarter of all people affected by the hepatitis A virus at any one time. Compared to adults, most infants and very young children suffer very mild cases in general, and up to three quarters of affected children show no symptoms at all, while the rest have a very low but persistent fever and may ache all over the body, symptoms of jaundice are however rare. Children are however major carriers of the disease and are one of the most likely sources of new infections for adults. Hepatitis A symptoms are much more severely felt by older patients, here the disease is characterized by an incidence o fever that can raise the body temperature to 100 or up to 104 degrees F, physical symptoms include extreme tiredness and fatigue, physical weakness is one of the most noticeable signs. Patients also tend to develop persistent nausea, and are affected by a stomach upset, there is a constant and persistent pain along the upper right side of the stomach, a significant loss of appetite is also almost always present. The skin develops a yellowish tinge and the whites of the eyes also turn yellow in color within a few days from the appearance of the first signs of infection. The stool of the affected person turns very light in color-while the urine is much darker than usual. Adults and all persons above twelve years of age may become very sick for a week or two at this stage from the appearance of initial symptoms. The condition of patients tends to improve when the first signs of jaundice have appeared and progressively gets better from this stage onwards. Most affected individuals recover within a few weeks without the incidence of major complications and the disease itself is very rarely fatal. Once the virus enters the body, it incubates for sometime; typically this incubation period lasts from 15 to 50 days in different patients. All patients with hepatitis A are at their most infectious in the first two weeks before the full development and manifestation of the symptoms. Therefore patients infected by the virus must make sure that they do not spread the virus especially if they handle food as a part of their job-they should not work until they cross the infectious stages, this stage is crossed one week after the first time symptoms of jaundice becomes apparent in the body. Trails of a new vaccine were carried out in 1996 in the United States, this vaccine was said to be a 100 percent effective in dealing with the condition following the single primary dose. Other vaccine tested earlier, ensured that at least 99 percent of people in the vaccine studies achieved immunity following two doses. This vaccine requires a booster shot between 6 and 12 months after the first dose so as to maintain proper immunity from the virus. Precautionary measures go a long way in preventing infections from unnecessarily occurring, for example all childcare workers in child care centers, who handle diapers, must follow strict rules - they must frequently wash their hands and must follow careful procedures when changing diapers. Contaminated food can be cooked to kill the virus before it is consumed. For example, to eat shellfish sourced from contaminated waters, it must be well cooked or boiled for at least eight minutes using high flame. Infection can also be prevented by those who have been exposed to the hepatitis A virus, by being shot with a dose of the immune globulin (IG). This protein is collected human blood plasma rich in protective antibodies that can fight against the disease and prevent symptoms from occurring. Shots of the IG is necessary for the following groups of people: shots must be given to all members of a household with an individual suffering from hepatitis A and this also applies to sex partners of hepatitis A affected individuals. These shots should also be given to close friends of an infected school-age child who may meet them on a daily basis. All staff in restaurant staffers where one food handler has hepatitis A must also be given these shots. This also applies to all patrons of the restaurant who must be given shots of IG two weeks following exposure to a food handler affected with the hepatitis A, especially if he or she handles uncooked food and has poor hygienic practices while serving and also otherwise if he or she is suffering from diarrhea. Shots must be given to the entire staff and residents of all places such as prisons, institutions and homes, if two or more residents have hepatitis A at any given time. Shots must also be given to the entire staff of child care centers or homes, especially when it is found that one or more children or one or more employees have developed a hepatitis A infection. All family members and other children must be given shots of IG in a home environment when three or more children or their other family members have hepatitis A. All individuals traveling to developing countries must be given these shots, especially if they have never been immunized against the condition.