March 22, 2017



Natural Standard Monograph, Copyright © 2013 (www.naturalstandard.com). Commercial distribution prohibited. This monograph is intended for informational purposes only, and should not be interpreted as specific medical advice. You should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

Related Terms

  • Adventure ecotourism, adventure tourism, cultural tourism, ecolodge, ecolodges, ecological impact of outdoor recreation, ecological tourism, eco-travel, fair trade, general ecotourism, green tourism, greenwashing, hard ecotourism, leakage, natural tourism, nature-based tourism, responsible tourism, soft ecotourism, sustainable tourism, zoonotic diseases.


  • Ecotourism is a type of recreational travel that, in the most general sense, strives to benefit the environment, celebrate its biodiversity, and introduce people to the surrounding area through eco-friendly touring.

  • Tourism may be divided into two distinct branches: conventional mass tourism and alternative tourism. Conventional mass tourism is mostly associated with large-scale trips that appeal to a general population, usually involving vacation destinations that provide luxury escapes and experiences. Often this form of tourism provides leisure at the expense of the surrounding natural environment, the local people and their culture, with a minimal contribution to the community's socioeconomic development.

  • In contrast, alternative tourism may be defined as types of travel that do not cater to a general tourist population; it is often associated with sustainable and environmentally friendly travel. Other terms related to alternative tourism include: sustainable tourism, green tourism, eco-travel, responsible tourism, adventure tourism, cultural tourism, natural tourism, nature-based tourism, and ecotourism.

  • Ecotourism, a form of alternative tourism, can be further subdivided into three categories: "hard" ecotourism, general or "soft" ecotourism, and adventure ecotourism. Hard ecotourism tends to involve a scientific interest in natural surroundings, wildlife and/or biodiversity. Hard ecotourism is the least luxurious form of ecotourism, often involving a lack of hotel accommodations or additional amenities. An example of hard ecotourism would be sleeping at an eco-friendly campsite.

  • General or "soft" ecotourism, which also revolves around a curiosity about nature, takes a somewhat less intense approach. Activities such as hiking are common, but they are considered recreational activities, not conduits for nature study as in hard ecotourism.

  • The last form, adventure ecotourism, focuses on intense or high-adrenaline activities such as kayaking, surfing, or whitewater rafting. Although adventure ecotourism may also involve camping and hiking, a greater emphasis is placed on extreme sports that use the natural environment as a medium; there is also an appreciation for the health of the ecosystem and its surrounding people.

  • Controversy centers around the question of whether ecotourism is ultimately beneficial or harmful. Although ecotourism may benefit a country economically, public health officials as well as economic and environmental analysts question whether it is worth the risk of environmental harm. It is also questionable whether the economic profits directly benefit the local residents and community.

  • Travelers from Western Europe, the United States, Canada, and Australia account for the majority of eco-tourists. Costa Rica, one of the most popular ecotourism destinations, is commonly cited in studies weighing the benefits and disadvantages of this type of travel. Other popular destinations include Palau in Micronesia, known for its clear blue waters and untainted marine life, and the Norwegian Fjords, famous for its pristine Nordic ecosystem. The African nation of Kenya has also been long appreciated for its diverse wildlife. Ecotourism destinations are found worldwide, with well-preserved ecosystems and wildlife as their common thread.


  • General: Seven distinct traits define ecotourism: 1) travel to natural destinations, 2) minimizing any negative impacts on the environment, 3) building environmental awareness, 4) providing direct funds for conservation, 5) providing funds for the empowerment of local people by developing a stronger economic and social infrastructure, 6) respect for local culture, and 7) support of human rights and democratic movements.

  • Eco-certified: In order to achieve these goals, non-profit organizations such as The International Ecotourism Society (TIES) and Sustainable Travel International (STI), have created accreditation and certification programs for businesses and travel-related organizations that wish to be recognized as eco-certified. Although ecotourism is generally associated with foreign travel to natural destinations, it is also present in the United States. The U.S. Green Building Council (USGBC), a non-profit organization, is an alliance of 15,000 businesses and organizations dedicated to creating environmentally responsible architecture. As a part of their mission, USGBC developed the LEED (Leadership in Energy and Environmental Design) Project Certification program, which measures a building's eligibility to be classified as environmentally friendly. LEED certification is awarded to buildings that reduce waste and greenhouse gas emissions, conserve energy and water, and reduce cost while increasing asset value. Many LEED-certified hotels are located in major metropolitan areas; examples include the Orchard Garden Hotel in San Francisco, California and the Best Western Inn and Suites at Dinosaur Ridge in Phoenix, Arizona. LEED certification currently does not extend outside of the United States. Many non-U.S. destinations, such as Costa Rica, do not formally designate official ecotourism areas, which often leads to incidences of misleading eco-marketing; this practice is also known as greenwashing.

  • Greenwashing is the misuse of marketing strategies to create an environmentally friendly appeal for products that in reality do not benefit the environment; in fact, these products may even harm their surroundings. Greenwashing extends beyond consumer products and into the travel industry, where some locations or activities may be marketed in misleading ways; these particular travel destinations make no attempt to uphold ecotourism ideals, such as sustaining the environment or helping the local people. The act of greenwashing may be as small as marketing a hiking tour as an eco-friendly tour when it may actually harm the local plant or animal life. Greenwashing may also have severe consequences, such as marketing a large-scale resort to travelers as an eco-friendly hotel, or "ecolodge," when it is not. This practice has led itinerary booking websites, such as Travelocity.com, to create an index of certified green destinations, citing the U.S. Environmental Protection Agency (EPA) STAR program and The Rainforest Alliance as standards for true ecotourism-friendly locations. The U.S. EPA STAR program assesses the energy-efficiency of buildings and consumer products, while the Rainforest Alliance is a non-profit program that provides eco-certification to travel destinations on a membership basis. However, membership and approval by both programs is not mandatory at most ecotravel destinations.

  • Ecolodges: According to the Conservation International Foundation, an "ecolodge" is a tourist accommodation that upholds the principles of ecotourism. In order to be classified as an ecolodge, TIES requires the following: 1) rooms decorated to reflect the local culture and to comfortably accommodate guests, 2) surroundings that have conserved both flora and fauna, 3) low-impact construction made of sustainable and/or recyclable materials from local resources, 4) the use of locally-grown food, 5) eco-friendly management of energy, water, and waste, and 6) interaction with and employment of the local populace.

  • Fair trade program/buying local products: Fair trade is a social and economic movement dedicated to helping developing countries; it advocates the payment of a "fair price" as well as the use of social and environmental standards (such as sustainability), in the production of a wide variety of goods. It particularly focuses on exports, most notably cultural and agricultural goods that travel from developing countries to developed countries. Programs that support the fair trade of products made by local farmers, producers, and artisans also strive to increase the economic contribution of travel to the local community. Organizations that are part of Fair Trade Certified Programs, such as the "Fair Trade Federation" (created by STI), must meet a particular set of standards to be placed in this classification. Producers must be paid fair wages, and long-term relationships must be established between producers and buyers. Cooperatives work closely with producers to reinvest their profits in the community; this activity may cultivate local economic development and increase the potential for growth. Coop buyers must support sustainable production techniques to ensure that they do not cause environmental harm. In addition, the product must preserve local cultural identity, and buyers must support the education of consumers about fair trade profits. Producers must be able to work in safe and healthy environments, and all financial transactions should uphold a degree of transparency to guarantee organizational accountability.

  • In order for the purchaser to recognize a product as being fairly traded, the Fair Trade Labeling Organization (FLO) was created in Germany. The FLO is a conglomerate of twenty international fair trade labeling initiatives, which individually regulate manufacturers and importers on a national basis. In the United States, TransFair USA is the labeling initiative responsible for maintaining fair trade. Truly fair-trade-certified products are marked by an International Fair Trade Certification Mark (CM); the CM is an image of a person holding two baskets, superimposed over a picture of a globe. Products, their producers, manufacturers, and importers, are all subject to audits on a regular basis, to ensure that the standards of fair trade certification continue to be met after certification is achieved. According to TransFair USA, the minimum price of a fair trade product is first established by setting a price that covers the cost of sustainable production. If the consumption of products or resources is so great that it threatens the ability of producers to continue at the same rate, the process is considered unsustainable. Similarly, if the rate of consumption results in depletion of limited resources (including habitats), then consumption cannot be sustained. For example, the minimum price of Arabica coffee is $1.25 per pound, with an additional $0.15 premium paid directly to farmers to benefit community and business efforts. Fair Trade offers both environmental and social benefits. As many fair trade products are shade-grown under rainforest canopies, and 80% of all fair trade products are organically grown (without chemicals or pesticides), participation in fair trade also ensures environmental protection. In addition, fair trade promotes the conservation of biodiversity in agricultural areas, as well as sustainability of the soil and natural environment. Producers who participate in fair trade ventures experience social benefits provided by membership in the FLO. One particular success story involved the prevention of illicit drug production in Columbia: Because the producers of more than 1,600 acres of cocoa trees and poppies were economically stabilized and socially supported by fair trade, illicit drug production was curtailed in favor of these other crops.

  • Reducing negative environmental impacts: In order to reduce the negative environmental impact of greenhouse gas emission, solid waste, energy consumption, and freshwater usage on the ecosystem, travel companies and environmentally friendly hotels have employed a variety of tactics. For example, to reduce freshwater waste, some ecotourism businesses have turned to gray water recycling. Gray water is the wastewater created by sinks, dishwashers, laundry machines, and restrooms. Recycling of this liquid waste for re-use in the same manner it was created reduces the amount of fresh, drinkable water that must be turned into gray wastewater. Also, new technologies such as a zero-emission aircraft are currently under development by companies like Boeing and Intelligent Energy and should enter the market within the next 50 years.

  • Because consumerism may generate large amounts of waste, effective management strategies are critical. Developing countries constrained by politics, social infrastructures, and economic and technological constraints may have inadequate waste management. The environmental impacts of waste disposal include an increase in landfills, water pollution, air pollution, and a rise in energy consumption. Additionally, in areas where waste management is poor, improper sanitation and the spread of disease may be issues. Thus, the impact of waste pollution on a developing country without an effective means of waste management may be profound.


  • General: Ecotourism focuses on travel in natural surroundings without bringing harm to the environment; it also helps to create opportunities for social and economic growth in the local population. The International Ecotourism Society (TIES) states that tourism is one of the top five national industries in more than 150 countries, and it is the number one industry in 60 nations. TIES calls attention to the importance of tourism in major developing countries. For a third of the world's poorest countries, tourism in general is the major export upon which their country relies. In the past, tourism has successfully provided the means for developing countries to bring about economic progress.

  • Economic benefits: Controversy exists over whether ecotourism ultimately brings about more good than harm to host countries. Costa Rica is one of the most popular destinations for ecotourists, given its biodiversity and well-supported wildlife conservation efforts; between 1988 and 1996, the number of foreign visitors to Costa Rica increased from 329,000 to 781,000 people. As a result, Costa Rica has enjoyed a number of economic windfalls. Since 1963, when the first protected region was created in Costa Rica, for example, the percentage of protected acreage has risen to 27% of the total land area. Within these protected areas, pharmaceutical companies such as Merck & Co. have funded research in conjunction with Costa Rica's National Biodiversity Institute; this Institute allots 50% of all royalties to benefit the country's national parks system. From 2000 to 2001, tourism in Costa Rica brought in total revenues of $1.1 billion. This profit benefits not only businesses directly related to tourism in the country, but also supports other associated industries, such as agriculture and construction. Similarly, the infusion of wealth brought in through ecotourism has benefited Costa Rica's socioeconomic development. Investments of ecotourism profits have improved public health, increased the literacy rate, and raised the level of economic stability. Research has shown a strong correlation between a nation's total income, or GDP (gross domestic product), and its literacy rate. For example, Costa Rica has an average GDP of $6,700 and a 95% literacy rate, whereas Ecuador has an average GDP of $3,000 and a 71% literacy rate. If properly managed, it appears that ecotourism and the associated economic boon that it brings may have a potential impact on the welfare of a host nation's citizenry.

  • Economic costs: Ecologies fail when internal or external forces prevent maintenance of a healthy equilibrium. Sustainability is a core concept in the application of a number of environmental sciences, and it has been proposed as a guiding principle in many areas of industry and government. The steady growth in consumption of resources by the world's population may or may not be sustainable. If consumption or production is so great that it threatens the ability of producers to continue at the same rate, then the process is unsustainable. For ecotourism, sustainability applies to the ability of the local populace and their environment to support and maintain recreational travel without harm.

  • Leakage is a term for the loss of revenue to foreign countries or businesses when developing a resource. In ecotourism, for instance, a portion of the profits may be lost to tour operators, hotel chains, or other services provided by foreign individuals and corporations. In developing countries, this profit leakage will often go to more developed nations. Leakage is a major concern for many developing countries that turn to foreign investors to fund development of their tourism industry. High leakage occurs in developing countries that must outsource their development overseas and then rely upon imports and foreign taxes. In turn, a large amount of the profit earned through the tourism industry is siphoned out of the host nation. The World Bank estimates that about 55% of the revenue acquired through tourism in lost to leakage in developing nations, though this figure may be substantially higher. According to estimates by the United National Environment Programme (UNEP), Thailand, a popular ecotourism destination, experiences a leakage of 70%. This is a general estimation of the Thai tourism industry as a whole; the leakage percentage due to ecotourism has yet to be quantified.

  • Greenwashing, a manipulation of the ecotourism interest that does not benefit the ecosystem or its surrounding areas, has also become a topic of concern. In marketing travel services as "green" or environmentally friendly when they are not, greenwashers harm the business integrity of true ecotourism companies as well as the ecosystem that true ecotourism strives to protect.

  • To study the question of local workforce exploitation in developing countries, a study was undertaken by Weaver in 1998 to quantify the percentage of profit returned vs. the amount of work conducted by the local residents. It found that in major hotels in developing countries, the local workforce contributed 93% of the work but were only paid 77% of their true earnings; the rest was paid to foreigners. Eva Garen, a sociologist who also studied ecotourism in developing nations, concluded that the majority of menial labor jobs in the travel industry are given to the local workforce. Often these jobs provide a lack of career mobility to higher positions. She also concluded that many of the positions in upper management are not available to local residents, and are solely filled by foreigners. Since much of a developing nation's workforce lacks the opportunity for higher education, this is not surprising. These points negate the intent of ecotourism, which seeks to provide economic opportunity to the surrounding local community. Some economists have argued that ecotourism may actually cause a breakdown in opportunity, though the prevailing belief remains that the economic benefits of ecotourism outweigh the costs.

  • Environmental benefits: As Costa Rica is one of the first ecotourism destinations in the world to undergo formal conservation efforts, it has been widely used as a model for studying the impact of ecotourism in developing countries. The introduction to ecotourism in Costa Rica has encouraged conservation in many of its rainforests. In turn, this has also encouraged business development of environmentally friendly industries, such as ecological research. Instead of utilizing its trees for profit through the logging industry, Costa Rica has created ties with pharmaceutical and biotechnology research companies such as Merck & Co. Fifty percent of the royalties achieved through these research projects directly benefit the national parks systems in Costa Rica.

  • Environmental costs: While tourism may benefit a small developing country by increasing revenue, it may also harm the ecosystem. Hundreds of thousands of tourists may take quite a toll on the infrastructure and natural resources of a developing nation. Often the local law enforcement that protects the grounds and surrounding wildlife is insufficient to combat the environmental havoc wreaked by tourists. Although the principles of ecotourism stress the importance of low-impact building methods in the development of tourist locales, the mere introduction of human construction may be enough to cause harm to the surrounding ecosystem. The United Nations Environment Programme reports that Egypt's coastline has undergone extensive development within the last few years. The two most popular sites, the Gulf of Aqaba and the Gulf of Suez, now contain extensive beach resorts; the development of these resorts has been reported as threatening to the local marine life, due to the potential destruction of coral reefs, sea grass beds, and mangrove forests by sediment from building materials and moving soil. Because the deposition of sediment from construction is difficult to immediately detect, the effects on both marine flora and fauna may be difficult to mitigate. Whereas the principles of ecotourism strive to construct tourist destinations that minimally impact the ecosystem, poor management can threaten and damage the surrounding environment. Australia, another popular ecotourism locale, has experienced a negative impact from outdoor recreation, an activity widely associated with adventure ecotourism. A study conducted by the Department of Forestry at the Australian National University assessed the effects of common tourist activities on the natural environment. The common tourist activities of bush walking, camping, and horseback-riding were found to affect both the surrounding vegetation and physical state of the soil. "Track formation, soil loss and/or compaction and an increase in fire" resulted from tourists hiking and camping. In addition littering and water pollution resulted from tourists utilizing the campgrounds or trail paths. Much of the harm to vegetation resulted from human activities which promoted the spread of pathogens and weeds. Two cited examples include myrtle wilt disease (an airborne disease that causes degradation of Myrtle Beech trees), and Phytophtora cinnamomi (a soil-based pathogen that causes the rotting of roots in various plants). In order to prevent environmental harm, host countries have begun to conduct research on the possibilities of inadvertent harm resulting from ecotourism.

Health Impact/Safety

  • Wildlife safety: While wildlife may benefit from the conservation efforts that stem from ecotourism, studies show that tourism may also harm animals. Chinese research followed the effects of ecotourism development on the mortality rate of Tibetan monkeys. Tibetan infant macaques in Anhui Province's Mt. Huangshan Scenic Area experienced a dramatically-increased mortality rate, due to their confinement to a restricted range and competition for corn and other food thrown by tourists. Researchers noted that aggression from adult macaques toward other adult and infant macaques resulted in a mortality rate greater than 50%.

  • Disease emergence: The spread of disease between animals and humans has become an issue of increasing concern. Studies have shown an increased susceptibility of endangered animals to human pathogens. In addition, zoonotic diseases (infectious diseases transferred from animals to humans), have caused several high-profile scares in recent years. Two of the most widely-noted cases of zoonotic diseases are the West Nile virus in the United States and the Rift Valley fever virus in Saudi Arabia.

  • The West Nile virus is typically transmitted by mosquitoes. It first appeared in the United States in 1999, but has commonly been found in Africa, Asia, the Middle East, and Europe. Most infections do not lead to illness. However, some people infected with the virus suffer flu-like symptoms; these symptoms may include fever, nausea, vomiting, headache, and fatigue, as well as neurologic complications.

  • The Rift Valley fever virus, of the genus Phlebovirus (family Bunyaviridae), occurs in central and southern Africa in sheep, goats, and cattle; it may cause fetal death or severe febrile disease, notably in young lambs. Humans, especially herdsmen and veterinarians, may become ill through close contact with infected animals; they may develop dengue-like symptoms (dengue fever is found in Africa and other tropical areas, with symptoms including red rash, headache and muscle joint aches lasting for about six days). The virus also infects buffaloes, camels, and antelope. It is mosquito-borne, but may also infect by direct contact and through the respiratory tract.

  • Immunizations are recommended for travel to under-developed countries. Although these immunizations protect from widely-recognized viruses, they do not protect travelers from all possible infections. The most commonly-recommended immunizations are: hepatitis A, typhoid, hepatitis B, yellow fever, MMR (measles, mumps, rubella), and tetanus-diphtheria.

  • Tetanus is a bacterial infection that affects the nervous system; it may result in severe muscle spasms. Tetanus, also called lockjaw, is a serious illness caused by tetanospasmin, a powerful nerve toxin produced by the bacterium Clostridium tetani. This organism is capable of living many years in the soil as a spore. Tetanus occurs when a wound becomes contaminated with these spores. Infection follows when spores become active, multiply, and begin producing a very powerful poison that affects the muscles. Tetanus spores are found throughout the environment, usually in soil, dust, and animal waste (such as manure). Clostridium may enter the body through splinters, insect bites, burns, drug injection sites, or through deep cuts or puncture wounds, such as when one steps on a nail. Deep wounds, or those with devitalized (dead) tissue, are particularly prone to tetanus infection. Tetanus toxoid (TT) vaccine protects against tetanus and neonatal tetanus infections. In contrast, Td (tetanus-diphtheria toxoid adult dose vaccine), has the added advantage of protecting against both diphtheria and tetanus. Td is the same vaccine as DT (diphtheria/tetanus), but with a lower diphtheria toxoid dose. It is suitable for adults and children older than six years old; it may also be used in pregnant women. When given to women of childbearing age, vaccines that contain tetanus toxoid (TT or Td) not only protect these women against tetanus, but also prevent neonatal tetanus in their newborn infants; this protection occurs because of antibodies formed in the mother's body that are passed to her fetus. These antibodies protect the baby against tetanus during birth and for a few months afterwards. A three-dose course of TT or Td provides protection against maternal and neonatal tetanus for at least five years. A maximum of five doses will protect women throughout their childbearing years. Adults should continue to receive a Td booster dose every 10 years.

  • Hepatitis A is a highly-contagious liver infection that is caused by the hepatitis A virus (HAV). Although not usually as serious as other types of viral hepatitis, hepatitis A causes inflammation of the liver that may affect its ability to function. The liver is primarily responsible for producing biochemicals necessary for digestion, as well as removing drugs, alcohol, and toxins from the bloodstream. Hepatitis A may be transmitted when a person consumes foods grown in contaminated soil, eats food that is prepared by someone with dirty hands, or drinks water that is contaminated by fecal matter. Most cases of hepatitis A cause mild, if any, symptoms and do not require medical treatment. However, in rare cases, hepatitis A may be life-threatening, causing liver failure. Hepatitis A may occur sporadically or in epidemics, and is commonly seen in school-age children and young adults. Necrosis (cell death) of liver tissue is characteristic of hepatitis A, and jaundice (yellowing of the skin) is a common symptom.

  • Typhoid fever is an infection of the intestines that affects the whole body. It is caused by the bacterium Salmonella typhi, found in the fecal matter of infected individuals. Typhoid is spread when a person ingests food or water contaminated by human waste (stool or urine) containing Salmonella typhi bacteria. Drinking water may become contaminated with fecal matter from contact with raw sewage. Individuals may be vaccinated against typhoid fever, although vaccination is not usually needed in the United States. In general healthcare professionals recommend vaccination only for international travelers who are going to developing countries where exposure to contaminated food or water is likely. Experts believe that vaccinating high-risk populations, such as those in developing countries, is the best way to control typhoid fever. Safe drinking water, improved sanitation, and adequate medical care are also essential in controlling outbreaks. It is recommended that individuals traveling to areas where typhoid fever is endemic should consider vaccination against S. typhi. Both an oral typhoid vaccine and a single-dose injectable vaccine are readily available; these vaccines are equally effective and offer 65-75% protection against the disease. The oral vaccine (Vivotif®) contains a live but weakened strain of the Salmonella bacteria that causes typhoid fever; the vaccine consists of four capsules that are taken every other day over a one-week period. The capsule enclosure protects the vaccine against stomach acid, allowing the vaccine to remain active until it reaches the intestines, where it is absorbed. The oral vaccine may be given as either a first-time dose or as a booster dose. Protection lasts about five years, at which time a booster dose would be needed if traveling again. The oral vaccine is not recommended for children under six years old. Vaccine side effects may include abdominal cramps, diarrhea, nausea and vomiting, and an itchy rash (urticaria). The single-dose injectable vaccine, Vi polysaccharide vaccine (ViCPS), contains a capsular polysaccharide antigen (a portion of the outer coating of the virus); it offers protection starting two weeks after injection. ViCPS immunizations should offer protection for two years. Subsequent booster doses are recommended at two-year intervals. This vaccine may be used in children as young as two. Side effects, while greater than those of the oral vaccine, are much less than those experienced with the older two-dose injectable vaccine. Vi polysaccharide vaccine may cause redness or swelling where the vaccine is given; it may also cause fever and headache.

  • The hepatitis B virus (HBV) causes a serious liver infection. This infection may become chronic in some people and lead to liver failure, liver cancer, cirrhosis (permanent scarring and damage of the liver), or death. The hepatitis B virus is transmitted through contact with bodily fluids, such as the blood, semen, and vaginal discharge of an infected person. Even though this transmission method is the same as human immunodeficiency virus (HIV), hepatitis B is nearly 100 times more infectious; this is because HBV is more concentrated than HIV. Individuals of any age, race, nationality, gender, or sexual orientation may become infected with HBV. There are few treatment options available for patients with chronic hepatitis B, which is why people in the United States are required to receive the vaccination to prevent infection. When HBV infection has been detected, a doctor may suggest monitoring the patient's condition instead of treating it. In other instances, a doctor may recommend antiviral treatment or immunomodulatory therapy. When liver damage is severe, a liver transplant may be the only treatment option. Hepatitis B vaccination is the best way to prevent hepatitis B infection. A hepatitis B vaccine (Engerix-B®) has been available since 1982. It is administered in a series of three injections and provides more than 90% protection for both adults and children for at least 15 years. Infants, older adults, and those with immune deficiencies are eligible to be vaccinated. Infants usually receive the vaccine during the first year of life, with injections administered at two, four and nine months of age. In the last decade, recombinant DNA technology has been used to produce the vaccine in the United States: Rather than creating the vaccine from the blood of infected patients, the HBV antigen is produced in a laboratory. Side effects from the vaccine tend to be mild and may include weakness, fatigue, headache, nausea, and soreness or swelling at the injection site. Although concerns have been raised that the HBV vaccine may increase the risks of autoimmune disease development and sudden infant death syndrome (SIDS), studies have found no such evidence.

  • Yellow fever is a tropical mosquito-borne viral hepatitis caused by an arbovirus (yellow fever virus) from the Flaviviridae family. The virus is transmitted by Aedes aegypti and Haemagogus capricorni mosquitoes, and infection is characterized by high fever, jaundice (yellowing of the skin), slow pulse, albuminuria (loss of the blood protein albumin), facial swelling, and hematemesis (vomiting of blood). Yellow fever immunization is mandatory in the United States for travelers to any of the following countries: Angola, Benin, Burkina Faso, Cameroon, Democratic Republic of the Congo, Gabon, Gambia, Ghana, Guinea, Liberia, Nigeria, Sierra Leone, Sudan, Bolivia, Brazil, Colombia, Ecuador, French Guiana, Peru, and Venezuela.

  • Measles, mumps, and rubella are highly contagious viral infections. However, they are rare in developed countries such as the United States, where individuals have access to vaccinations. Measles is a viral infection of the respiratory tract; mumps is an infection of the salivary glands. Rubella, also called German measles, is a mild infection of the respiratory tract that often goes unnoticed. However, if a pregnant woman develops rubella, it may lead to birth defects in the infant. People may become infected with the viruses when they inhale infected particles from the air. The viruses become airborne when an infected person coughs, sneezes, talks, or spits. A vaccination against measles became available in 1963, and an improved measles vaccine became available in 1968. A combination measles-mumps-rubella (MMR) vaccine became available in 1971, and a combination measles-mumps-rubella-varicella (MMRV) vaccine became available in 2005. The MMR vaccine contains live virus particles of the three viruses, which have been weakened to stop them from producing the full effects of the disease. The vaccine is given by injection into the thigh or upper arm. It has been found that a booster given to already-immunized children before they enter school makes it more likely that they will be properly protected. After initial immunization, a booster injection or booster dose is essentially a re-exposure to the MMR vaccine, intended to restore an individual's immunity back to protective levels. There is no risk of someone who has been vaccinated infecting other people with the viruses. The MMR vaccine is recommended for the following groups: all children and adolescents, beginning at age 12-15 months; adults born in 1957 or later without evidence of vaccination or evidence of immunity (antibodies in the bloodstream); healthcare workers, regardless of age; immigrants to the United States from other countries; and non-pregnant women of childbearing age without other evidence of immunity to rubella. All children and adolescents should receive two vaccine doses, no less than four weeks apart. Most children vaccinated at 12-15 months should receive a second dose at age four to six years. All older children and adolescents should receive the second dose at the next available opportunity, as long as there has been a four-week interval since the previous dose. The first dose of MMR vaccine produces immunity to measles in 95-98% of children vaccinated. A second dose is given to protect those persons who did not become immune after one dose. After two doses of measles vaccine, 99% of persons become immune to the disease. Healthcare professionals recommend that a second dose of MMR should be given to any adult born in 1957 or later who: is a student in a post-secondary educational institution (college); is an immigrant from another country; is a healthcare worker; plans to travel internationally; is exposed to measles in an outbreak setting; was previously vaccinated with killed measles vaccine; or was vaccinated with an unknown type of measles vaccine that was found to be ineffective during 1963-1967.

  • Diphtheria is a serious bacterial infection that usually affects the nose and throat. Most patients become infected after inhaling the bacteria; they develop thick, gray membranes in the backs of their throats that may cause difficulty breathing. If the bacteria enter a wound instead, diphtheria may affect the skin. Some individuals may become infected with the bacteria, but only experience mild symptoms or none at all. These individuals are called "carriers," because they can still spread the infection to others. For the purpose of convenience, a combination vaccine called DT protects against diphtheria and tetanus. This shot may be given to individuals who are younger than seven years of age.

  • Travelers interested in obtaining more information on immunizations should research recommendations pertinent to the country to which they are traveling, as certain diseases may be prevalent in different locations. The Centers for Disease Control and Prevention (CDC) maintain a database where travelers can search for their travel destinations and view all of the health and safety information specific to that country.

  • The U.S. Geological Survey (USGS) reports that ecotourism may also play a role in the transmission of human diseases to animals. For example, several cases of tuberculosis (TB) were reported in Botswana's Chobe national park; these cases killed both mongooses and meerkats. TB is a bacterial infection caused by the bacterium Mycobacterium tuberculosis. The bacteria usually attack the lungs but can also damage other parts of the body, such as the lymph nodes, kidneys, and bones. It is believed that mongooses in Botswana contracted TB through contact with infected human waste. This occurrence highlights the possible harms of ecotourism and the susceptibility of wildlife to human diseases.

  • The U.S. Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) suggests that several aspects of ecotourism may contribute to disease emergence. For instance, diseases may occur when people visit an undeveloped area that lacks adequate medical care. Tourists may have an increased risk of developing local diseases that the native population has developed immunity to. In addition, tourists may be exposed to new diseases from animals or arthropods (e.g. mosquitoes, ticks).

  • Disease transmission is a serious concern while traveling, and tourists should educate themselves concerning risks of infection.

  • Studies have also noted a trend of disease emergence among developing countries that are experiencing environmental changes as a result of tourism. For instance, deforestation and land clearing associated with the development of tourist areas has been blamed for a variety of zoonotic infections. One such outbreak was caused by the Menangle virus, of the family Paramyxoviridae, which infected pigs, humans, and fruit bats in Australia. Human infection with the Menangle virus results in an influenza-like illness with rash.

  • In addition to native disease vectors such as mosquitoes, travelers must also be concerned about food and water sanitation in developing countries. As not all developing countries have established effective water purification programs, contamination of the water supply remains a possibility. Meat that is not cooked carefully, or produce that has not been properly cleaned, may also serve as potential sources of infection. Food-borne zoonotic diseases include salmonellosis and brucellosis. Salmonellosis is an infection with bacteria of the genus Salmonella. Salmonella may cause serious and sometimes fatal infections, particularly in young children, frail or elderly people, and those with weakened immune systems. Healthy persons often experience fever, diarrhea (which may be bloody), nausea, vomiting, and abdominal pain. Brucellosis, also known as Bang's disease, is primarily passed among animals, although humans may become infected by coming into contact with contaminated animals or animal products. Cases of human infection chiefly occur through the consumption of unpasteurized dairy products. According to the CDC, the Mediterranean Basin (Portugal, Spain, Southern France, Italy, Greece, Turkey, North Africa), South and Central America, Eastern Europe, Asia, Africa, the Caribbean, and the Middle East are listed as high risk areas for brucellosis. The disease causes intermittent fevers and flu-like symptoms, and recovery may require several months.

  • Whereas not all diseases affect humans directly, travelers should beware of serving as vectors of transmission between animal populations. Some microbes may attach to articles of clothing or other items and remain dormant for some time until the travelers return to their home countries. Once there, they may then infect domestic animals and cause epidemics within a previously healthy population.

  • Although the risk of mechanical transmission is moderate to low, the Bureau of Consular Affairs recommends that travelers to avian flu-infected countries avoid poultry farms and contact with animals in live markets; the spread of avian flu (also called bird flu) correlates to the movements of livestock equipment and people. Avian flu (so called as it primarily infects fowl such as chickens, ducks, and geese), is generally transmitted through an infected bird's fecal matter, where the virus may survive for up to 105 days. Several cases of human infection with bird flu viruses have occurred since 1997, mostly in Asia. Human infections with avian influenza A virus have not been identified in the United States.

  • Three major types of influenza viruses cause the flu: types A, B, and C. These types are further divided into virus subtypes and then into strains. There is an enormous number of potential strains of influenza viruses that may infect humans; the influenza virus is able to evolve and change, effectively dodging the immune system's recognition of the virus. When the influenza virus is no longer recognized by a person's immune system, it may re-infect the individual. Type A viruses, such as bird flu, most commonly affect adults and are the most severe, while type B viruses typically affect children and may also cause severe illness. Type C influenza causes either a very mild illness (usually in children) or no symptoms at all; it does not lead to the epidemics, nor have the severe public health impact caused by influenza types A and B. The death rate for reported cases of avian flu has been about 50% in infected humans and may approach 100% in birds. The avian flu virus is mainly transmitted to humans through direct contact with live or dead poultry; however, it is believed that a few cases of human-to-human spread may have occurred.

Future Research or Applications

  • As researchers are increasingly aware of the possible negative impacts of ecotourism, the matter has received more scientific attention. Studies are currently underway to quantify the tradeoff between the environmental impact and socioeconomic benefits of ecotourism. It has been recommended that further research be conducted to determine where those major impacts occur and how they may be minimized or prevented.

  • In order to minimize leakage of tourism profits to foreign nations and corporations, some countries have instituted controls to encourage local investment and participation in eco-tourism developments. Other countries have invested in their own development. One example of such an effort is the Kakum Canopy walkway in Ghana, Africa: A portion of the earnings from admission fees are directed to maintenance of the walkway. The remaining funds assist the Ghana Heritage Conservation organization in supporting the continued operation of the walkway, as well as other conservation and sustainable development projects in the communities around Kakum.

Author Information

  • This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).


Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

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Copyright © 2013 Natural Standard (www.naturalstandard.com)

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.


March 22, 2017