The disease varies from minor flu-like illness to liver failure. Disease transmission occurs by contact with infected feces-either through direct person-to-person contact, through the water supplies contaminated with human sewage, or through contaminated foods (such as raw shellfish drawn from polluted waters or food prepared by an infected person). Prevention of hepatitis A for persons at risk depends on good personal hygiene, taking care with food and beverages, and immunization with Hepatitis A vaccine. Travelers are at risk, especially if travel plans include visiting rural areas and extensive travel in the countryside, frequent close contact with the local persons, or eating in settings of poor sanitation.
Two doses with the second dose administered 6 months after the initial dose is needed to complete the series. Persons can assume to be protected by 4 weeks after receiving the first dose of vaccine; although a second dose 6-12 months later is necessary for long-term protection.
Hepatitis B virus is transmitted by contact with blood or other body fluids infected with the virus. Sexual contact is one of the most common means of transmission. Transmission may occur through transfusion of infected blood or blood products, the use of contaminated syringes and needles or dental or medical instruments, or non-medical practices involving skin puncture such as tattooing, acupuncture, ear piercing or even sharing a razor.
Hepatitis B vaccine is now recommended for all children and adolescents in the United States. If you have not had this vaccine, you should receive a series of three injections with the second and third dose given one and six months, respectively, after the first. Optimum protection is not obtained until after the third dose.
Malaria remains the number one infectious disease in the world and the risk to travelers is increasing. Malaria is caused by a parasite that is transmitted from person-to-person by the bite of an infected Anopheles mosquito. The disease occurs primarily in tropical and subtropical regions of Africa, Asia, Central and South America and Oceania. Even a brief exposure-such as one night’s travel to a malarias area provides a risk for the disease and preventative medication should therefore be taken. It is even possible to develop malaria after brief stopovers at international airports in malaria zones.
Specific recommendations for malaria chemoprophylaxis are influenced by several factors, including susceptibility of P. falciparum to choloroquine and Fansidar in different geographic areas, seasonal variations in the risk for exposure, and local malaria-free regions (usually urban or mountainous areas) within a country. Chemoprophylaxis should begin 1 to 2 weeks before entering an infected area to ensure adequate blood levels. Treatment should continue weekly during the period of malaria exposure and for 4 weeks thereafter. CDC provides information on the anti-malarial medication to be used when traveling to specific areas. The college physician may give you a written prescription for the medication, which can be obtained from a pharmacy.
Meningococcal meningitis is an acute bacterial infection of the brain lining. The disease occurs worldwide and usually strikes in epidemics. The disease is caused by an infection of the upper respiratory tract. Transmission can occur via inhalation of airborne droplets (talking, coughing), intimate contact (kissing), or contact with objects that are freshly soiled from an infected carrier’s nasal or oral secretions (tissue, contaminated dishes or beverage containers). Most carriers do not develop the illness, but they may transmit the disease for about 6 months. The incubation period is 1-10 days (usually less than 4).
Typhoid fever is a bacterial infection of the digestive tract, caused by Salmonella typhi. It is present throughout the world and is particularly prevalent in countries with warm climates and with less developed sanitary facilities or sewage disposal and water treatment. Typhoid is endemic in many countries in Africa, Asia, and Latin America. The source of the infection is the urine or feces of a human case or carrier. The disease is usually acquired by ingestion of contaminated food or water, particularly from the hands of carriers. Humans are the sole reservoir hosts. The bacteria are shed in feces, typically as long as 6 weeks to 3 months after the infections. Some persons remain infectious as chronic carriers. The incubation period is 1-3 weeks. It is most often found in persons 15-25 years old, and has a 5% mortality rate, even with treatment.
The most effective prevention for typhoid-related diseases, as, with other diarrhea diseases, is careful selection of food, water and beverage.
A vaccine against typhoid is recommended for persons visiting areas with poor food and water sanitation in developing countries. This included those going to endemic areas who will be venturing off the usual tourist routes into small cities, villages, and rural areas. Importance of vaccination increases as access to reasonable medical care decreases. It is also recommended for travelers who will be swimming.
Oral Typhoid vaccine is a series of 4 tablets. Take one tablet every other day for a total of 4 tablets on days 1, 3, 5 and 7 prior to travel. The capsule should be taken with a cool liquid (body temperature, not hot) 1 hour before a meal. Capsules must be kept refrigerated at all times.
The Oral Typhoid series should be completed prior to initiating malaria prophylaxis, if possible, as Mefloquine may decrease the immune response of oral typhoid. Mefloquine should be taken at least 24 hours before ingesting an oral typhoid vaccine capsule if the person has begun malaria prophylaxis prior to initiating typhoid immunization. Revaccination with oral typhoid vaccine should be done every 5 years.
Cholera is an acute intestinal infection usually acquired by drinking or eating contaminated water or food. The cholera-causing organism is contained in an infected person’s fecal material. Cholera symptoms usually occur about one to three days after exposure. It is highly unlikely that the tourist who exercises care regarding food and drink will be at risk for development of cholera.
Cholera vaccine is only about 50% effective in reducing illness from infections for 3-6 months. The risk of cholera to U.S. travelers is so low that it is questionable whether vaccination is of benefit.
Yellow fever is a mosquito-borne viral disease of the liver that occurs in parts of Africa and South America. The illness varies in severity from the flu-like syndrome to severe hepatitis and hemorrhagic fever. Incubation period is 3-6 days. In addition to vaccine, travelers should take precautions against exposure to mosquitoes when going to areas with yellow fever. In urban areas, it is transmitted to humans through the bite of an infected mosquito. In forest and savanna areas, the disease is transmitted from mosquitoes and monkeys to humans. Since mosquito control is impractical in such areas, the only effective means to combat yellow fever there is by vaccination.
The vaccine against yellow fever is highly effective and should be considered by nearly everyone traveling to an area of yellow fever risk since the cause-fatality rate for the disease is more than 60% in non-immune adults. Yellow fever vaccine can be obtained only from designated public health-approved centers. Some countries require an International Certificate of Vaccination Document for yellow fever. The certificate is valid for a period from 10 days to 10 years after immunization.
In many areas of the world rabies is still endemic and can pose a substantial threat to travelers. Rabies is a viral infection that affects the nervous system. Rabies is transmitted by mammal bites, which introduce the virus into the wound. Although dogs are the main reservoir if the disease, all mammal bites should be suspect. Travelers should be aware of the risk of acquiring rabies although rabies vaccine is not required for entry into the country.
Pre-exposure prophylaxis should be considered for anyone planning extended travel to high-risk areas.
Three injections (1 ml each) of Human Diploid Cell Vaccine HDCV are given in the deltoid area on days 0, 7, and 28.
Concurrent chloroquine prophylaxis for malaria requires that the rabies vaccine be given intramuscularly or subcutaneously because chloroquine impairs the antibody response to intra-dermal administered rabies vaccine.