Tropical medicine is an interdisciplinary branch of medicine that deals with health issues that occur uniquely, are more widespread, or are more difficult to control in tropical and subtropical regions.
Physicians in this field diagnose and treat a variety of diseases and ailments. Most infections they deal with are endemic to the tropics. A few of the most well-known include malaria, HIV/AIDS, and tuberculosis. They must be knowledgeable in the 18 lesser known neglected tropical diseases, which include Chagas disease, rabies, and dengue. Poor living conditions in developing regions of tropical countries have led to a rising number of non-communicable diseases as well as the prevalence of neglected tropical diseases. These diseases include cancer and cardiovascular disease, which, in the past, have been more of a worry in developed countries. Physicians trained in tropical medicine must also be prepared to diagnose and treat these diseases.
Training for physicians wishing to specialize in tropical medicine varies widely over the different countries. They must study epidemiology, virology, parasitology, and statistics, as well as the training required of an ordinary MD. Research on tropical diseases and how to treat them comes from both field research and research centers, including those of the military.
Sir Patrick Manson is recognized as the father of tropical medicine. He founded the London School of Hygiene & Tropical Medicine in 1899.He is credited with discovering the vector by which elephantiasis was being passed to humans. He learned it was a microscopic nematode worm called filariasanguinis hominis. He continued to study this worm and its life cycle and determined the worms underwent metamorphosis within female culex fatigans mosquitoes. Thus he discovered mosquitoes as a vector for elephantiasis. After this discovery, he collaborated with Ronald Ross to examine the transmission of malaria via mosquito vector. His work with discovering vectors as modes of transmission was critical in the founding of tropical medicine and our current understanding of many tropical diseases.
Training in tropical medicine is quite different between countries. Most physicians are trained at institutes of tropical medicine or incorporated into the training of infectious diseases.
In the UK, if a physician wants to specialize in tropical medicine, they must first train in general internal medicine and get accepted into the Royal College of Physicians. They must simultaneously study the specialty of infectious diseases while completing a full-time course load to receive their Diploma of Tropical Medicine and Hygiene. Their studies are carried out at either the London or Liverpool schools of tropical medicine. Additionally, they must spend two years at one of the UK centers approved for tropical medicine (located in London, Liverpool, or Birmingham). Physicians in the UK who wish to be certified in tropical medicine must spend at least a year abroad in an area lacking resources. Only then can they become certified in tropical medicine.
The training of United States tropical doctors is similar, though it is not a board recognized specialty in America. Physicians must first complete medical school and a program focusing on infectious diseases. Once completed, physicians can take the certification exam from the American Society of Tropical Medicine and Hygiene in order to receive the Certificate of Knowledge in Clinical Tropical Medicine and Travelers' Health.
In developing countries alone, 22 million people are living with HIV. Most infections are still in Africa, but Europe, Asia, Latin America, and the Caribbean are now seeing large numbers of infections as well. [ dubious ] Tuberculosis is thought to cause a more rapid disease progression. Tuberculosis is prevalent in tropical and under-developed countries, only making HIV more devastating. Without the expensive and high-tech medical equipment of developed, western countries, physicians in the tropics are left with few options. If they are able to catch an HIV-related bacterial or mycobacterial disease they can diagnose and manage the disease with basic drugs and standard treatment protocol. Many under-developed countries do not have a care strategy, and of those that do, they aren't as effective as they need to be to stop the spread of HIV.95% of expected new infections will occur in the low-income countries in the tropics. The expected number of new infections is 3-4 million per year. Risk factors such as needle use and unprotected sex are much more prevalent in tropical and underdeveloped areas. Once HIV is transmitted to a tropical area it is spread throughout the sexually active population. Though how fast and how far it spreads varies, some African countries have an HIV prevalence of 10%. More alarming still, in urban areas, prevalence among pregnant women can get as high as 30%. Healthcare professionals themselves are at great risk of exposure to HIV. An HIV prevalence of 10% means any given workforce will also have a 10% prevalence, and this does not exclude the healthcare team.
Malaria is a parasitic disease transmitted by an Anopheles mosquito to a human host.The parasite that causes malaria belongs to the genus Plasmodium . Once infected, malaria can take a wide variety of forms and symptoms. The disease is placed into the uncomplicated category or the severe category. If quickly diagnosed and treated, malaria can be cured. However, some of the more serious symptoms, such as acute kidney failure, severe anemia, and acute respiratory distress syndrome can be fatal if not dealt with swiftly and properly. Certain types of Plasmodium can leave dormant parasites in the liver that can reawaken months or years later, causing additional relapses of the disease. In the World Malaria Report of 2016, the World Health Organization reported a malaria infection rate of 212 million, 90% of which occurred in the African region. However, malaria infection rates had fallen 21% since 2010 at the time of the report. The WHO also reported an estimated mortality rate of 429,000 deaths in the year 2015. The malaria mortality rate had fallen 29% globally since 2010. Children under 5 contract the malaria disease more easily than others, and in the year 2015, an estimated 303,000 children under the age of 5 were killed by malaria. Since the year 2010 however, the mortality rate of children under 5 fell by an estimated 35%.
Tuberculosis (TB) is an infectious bacterial disease that can affect any part of the body, though it primarily affects the lungs. It is a disease that affects the poor and weak, and is far more common in developing countries.TB can either be in its latent or active form. TB can be latent for years, sometimes over a decade. Though TB research receives a mere 1/6th the funding of HIV research, the disease has killed more people in the last 200 years than any other infectious disease. According to the Liverpool School of Tropical Medicine, an estimated 9 million people were infected with TB in the year 2013 alone. That same year 1.5 million people died from TB. Of those 1.5 million, 360,000 were HIV positive. Tuberculosis is extremely expensive to treat, and treatments are now becoming ineffective due to drug-resistant TB strains. In the year 2016, 1.3 million people died from TB. An additional 374,000 people died who were co-infected with both TB and HIV. Research has shown that if the subject is infected with HIV, the risk of latent TB becoming active TB is between 12 and 20 times higher.
Non-communicable diseases are a series of chronic illnesses such as cardiovascular disease, cancer, injuries, and respiratory diseases, among others. Historically these diseases have plagued developed countries far more than developing countries.In the Global Burden of Disease Study of 2001, it was discovered that 20% of deaths in sub-Saharan Africa were caused by non-communicable diseases. In 2005, the World Health Organization performed a study that showed 80% of chronic disease deaths occurred in low to middle income countries. Non-communicable disease prevalence has been rising in under-developed countries for a variety of reasons. Lack of education and preventive medicine in under-developed countries, along with malnutrition or poor diet lead to many risk factors for non-communicable diseases.
Neglected tropical diseases (NTDs) have been identified by the World Health Organization (WHO) as 18 tropical diseases, affecting over a billion people worldwide, especially in developing countries. These diseases are heterogeneous, meaning originating outside the organism affected by the disease. NTDs are caused by parasites, viruses, and bacteria. NTDs are neglected because they are not normally fatal on their own but are disabling. Persons with these diseases become more susceptible to other NTDs and fatal diseases such as HIV or malaria.
Neglected tropical diseases effect can be measured in disability-adjusted life year (DALY). Each DALY corresponds to one lost year of healthy life, whether by death or disability. In the year 2010, it was estimated 26.6 million DALYs were lost. In addition to this, it is estimated NTDs cause a loss of 15–30% of productivity in countries that NTDs are endemic too.According to the CDC, 100% of countries categorized as 'low income' were affected by 5 different NTDs at once.
Tropical medicine requires an interdisciplinary approach, as the infections and diseases tropical medicine faces are both broad and unique. Tropical medicine requires research and assistance from the fields of epidemiology, microbiology, virology, parasitology, and logistics. Physicians of tropical medicine must have effective communication skills, as many of the patients they interact with do not speak English comfortably. They must be proficient in their knowledge of clinical and diagnostic skills, as they are often without high-tech diagnostic tools when in the field. For example, in an attempt to manage the Chagas disease being brought into the almost Chagas-free Brazilian city São Paulo by Bolivian immigrants, an interdisciplinary team was set up. The Bolivian immigrant population in São Paulo had a prevalence of Chagas disease of 4.4%, while Chagas disease transmission in São Paulo has been under control since the 1970s. This influx of Chagas disease led to an interdisciplinary team being brought together, This team tested the feasibility of managing Chagas disease and transmission at the primary healthcare level. The interdisciplinary team consisted of community health agents and clerical healthcare workers to recruit Chagas infected persons for the study, physicians, nurses, lab workers, and community agents. A pediatrician and cardiologist were also on call. Each were trained in pathology, parasitology, ecoepidemiology, and how to prevent, diagnose, and control Chagas disease. Training from experts in these respective fields was required. They examined reasons for lack of adherence to treatment, and used this knowledge to improve the effectiveness of their interventions. This interdisciplinary approach has been used to train many teams across Brazil in the management of Chagas disease.
Tropical medicine also consists of a preventive approach, especially in an educational aspect. For example, from 2009 to 2011, the London School of Hygiene & Tropical Medicine did an interventional study on a cohort of female sex workers (FSW) in Ouagadougou, Burkina Faso, a country in Western Africa. 321 HIV-unaffected FSWs were provided with peer-led HIV/STI education, HIV/STI testing and care, psychological support, general healthcare, and services for reproductive health. The same cohort would continue to follow up, quarterly, for 21 months. At each follow-up they were tested for HIV and were able to utilize the preventive interventions if need be. Using models based on the same study population had their been no interventions, the expected prevalence of HIV infections was 1.23 infection per 100 person years. In the actual cohort with access to interventions not a single HIV infection was observed in the collective 409 person-years of follow-up.
Throughout history, American military forces have been affected by many tropical diseases. In World War II alone, it was estimated almost one million soldiers had been infected by a tropical disease while serving. Most affected soldiers served in the Pacific, especially in the Philippines and New Guinea. Malaria was especially widespread in the Pacific, though soldiers in Southern Europe and Northern Africa also contracted tropical diseases.Many diseases now known as neglected tropical diseases affected America soldiers as well. These included helminthiasis, schistosomiasis, dengue, and lymphatic filariasis. Lymphatic filariasis was such a problem it caused a $100 million evacuation of U.S. troops out of New Guinea and the Tonga Islands.
In both the Korean and Vietnam Wars the United States army continued to be affected by tropical diseases. The most prevalent diseases to affect their military were malaria and dengue. Hepatitis A, scrub typhus, and hookworm infections were among the other tropical infections picked up by troops in these conflicts.
To combat the significant effects tropical diseases were having on their forces, the United States Military worked hard to develop drugs, vaccines, and other methods of disease control. Research done at the Walter Reed Army Institute of Research (WRAIR), the Naval Medical Research Center (NMRC), and various affiliated research centers have greatly improved the military's preparedness against tropical disease. In 1967, Captain Robert Phillips earned the Lasker Award for developing a type of IV therapy that reduced cholera's fatality rate from 60% to less than 1%. Other interventions licensed by the US Army include vaccines for hepatitis A and Japanese encephalitis. They have also developed the drugs mefloquine and malarone, both used in the treatment of malaria.
Looking forward, the United States military currently has clinical trials testing for vaccines of malaria, adenovirus infection, dengue, and HIV/AIDS underway.However, with massive budget cuts to their military, these research centers are getting less and less funding and have lost many contractors already.
Tuberculosis (TB) is an infectious disease usually caused by Mycobacterium tuberculosis (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in which case it is known as latent tuberculosis. Around 10% of latent infections progress to active disease which, if left untreated, kill about half of those affected. Typical symptoms of active TB are chronic cough with blood-containing mucus, fever, night sweats, and weight loss. It was historically referred to as consumption due to the weight loss associated with the disease. Infection of other organs can cause a wide range of symptoms.
Trichuriasis, also known as whipworm infection, is an infection by the parasitic worm Trichuris trichiura (whipworm). If infection is only with a few worms, there are often no symptoms. In those who are infected with many worms, there may be abdominal pain, fatigue and diarrhea. The diarrhea sometimes contains blood. Infections in children may cause poor intellectual and physical development. Low red blood cell levels may occur due to loss of blood.
Tropical diseases are diseases that are prevalent in or unique to tropical and subtropical regions. The diseases are less prevalent in temperate climates, due in part to the occurrence of a cold season, which controls the insect population by forcing hibernation. However, many were present in northern Europe and northern America in the 17th and 18th centuries before modern understanding of disease causation. The initial impetus for tropical medicine was to protect the health of colonial settlers, notably in India under the British Raj. Insects such as mosquitoes and flies are by far the most common disease carrier, or vector. These insects may carry a parasite, bacterium or virus that is infectious to humans and animals. Most often disease is transmitted by an insect bite, which causes transmission of the infectious agent through subcutaneous blood exchange. Vaccines are not available for most of the diseases listed here, and many do not have cures.
Helminthiasis, also known as worm infection, is any macroparasitic disease of humans and other animals in which a part of the body is infected with parasitic worms, known as helminths. There are numerous species of these parasites, which are broadly classified into tapeworms, flukes, and roundworms. They often live in the gastrointestinal tract of their hosts, but they may also burrow into other organs, where they induce physiological damage.
Hookworm infection is an infection by a type of intestinal parasite known as a hookworm. Initially, itching and a rash may occur at the site of infection. Those only affected by a few worms may show no symptoms. Those infected by many worms may experience abdominal pain, diarrhea, weight loss, and tiredness. The mental and physical development of children may be affected. Anemia may result.
Latent tuberculosis (LTB), also called latent tuberculosis infection (LTBI) is when a person is infected with Mycobacterium tuberculosis, but does not have active tuberculosis (TB). Active tuberculosis can be contagious while latent tuberculosis is not, and it is therefore not possible to get TB from someone with latent tuberculosis. The main risk is that approximately 10% of these people will go on to develop active tuberculosis. This is particularly true, and there is added risk, in particular situations such as medication that suppresses the immune system or advancing age.
Diseases of poverty are diseases that are more prevalent in low-income populations. They include infectious diseases, as well as diseases related to malnutrition and poor health behaviour. Poverty is one of the major social determinants of health. The World Health Report (2002) states that diseases of poverty account for 45% of the disease burden in the countries with high poverty rate which are preventable or treatable with existing interventions. Diseases of poverty are often co-morbid and ubiquitous with malnutrition. Poverty increases the chances of having these diseases as the deprivation of shelter, safe drinking water, nutritious food, sanitation, and access to health services contributes towards poor health behaviour. At the same time, these diseases act as a barrier for economic growth to affected people and families caring for them which in turn results into increased poverty in the community. These diseases produced in part by poverty are in contrast to diseases of affluence, which are diseases thought to be a result of increasing wealth in a society.
The Drugs for Neglected Diseases initiative (DNDi) is a collaborative, patients' needs-driven, non-profit drug research and development (R&D) organization that is developing new treatments for neglected diseases, notably leishmaniasis, sleeping sickness, Chagas disease, malaria, filarial diseases, mycetoma, paediatric HIV, cryptococcal meningitis, hepatitis C, and dengue. DNDi's malaria activities were transferred to Medicines for Malaria Venture (MMV) in 2015.
Neglected tropical diseases (NTDs) are a diverse group of tropical infections that are common in low-income populations in developing regions of Africa, Asia, and the Americas. They are caused by a variety of pathogens, such as viruses, bacteria, protozoa, and parasitic worms (helminths). These diseases are contrasted with the "big three" infectious diseases, which generally receive greater treatment and research funding. In sub-Saharan Africa, the effect of neglected tropical diseases as a group is comparable to that of malaria and tuberculosis. NTD co-infection can also make HIV/AIDS and tuberculosis more deadly.
Tuberculosis is a serious public health problem in China. China has the world's third largest cases of tuberculosis, but progress in tuberculosis control was slow during the 1990s. Detection of tuberculosis had stagnated at around 30% of the estimated total of new cases, and multidrug-resistant tuberculosis was a major problem. These signs of inadequate tuberculosis control can be linked to a malfunctioning health system. The spread of severe acute respiratory syndrome (SARS) in 2003, brought to light substantial weaknesses in the country's public health system. After the government realized the impact that the SARS outbreak had on the country, they increased leadership in their health department. After the SARS epidemic was brought under control, the government increased its commitment and leadership to tackle public health problems and, among other efforts, increased public health funding, revised laws that concerned the control of infectious diseases, implemented the world's largest internet-based disease reporting system to improve transparency, reach and speed, and started a program to rebuild local public health facilities and national infrastructure.
Health in Ethiopia has improved markedly since the early 2000s, with government leadership playing a key role in mobilizing resources and ensuring that they are used effectively. A central feature of the sector is the priority given to the Health Extension Programme, which delivers cost-effective basic services that enhance equity and provide care to millions of women, men and children. The development and delivery of the Health Extension Program, and its lasting success, is an example of how a low-income country can still improve access to health services with creativity and dedication.
Thailand has had "a long and successful history of health development," according to the World Health Organization. Life expectancy is averaged at seventy years. Non-communicable diseases form the major burden of morbidity and mortality, while infectious diseases including malaria and tuberculosis, as well as traffic accidents, are also important public health issues.
Refugee health is the field of study on the health effects experienced by people who have been displaced into another country or even to another part of the world, as a result of unsafe circumstances such as war or persecution. People who have been displaced can be affected by infectious diseases or some chronic diseases that are uncommon in the country in which they eventually settle. Mental health is an important consideration and can greatly impact people who are displaced. The health status of refugee's can be tied to factors such as the person who migrated's geographic origin, conditions of refugee camps or urban settings where they lived, and personal, physical, and psychological conditions of the person, either pre-existing or acquired while traveling from their homeland to a camp or eventually to their new home.
The quality of health in Cambodia is rising along with its growing economy. The public health care system has a high priority from the Cambodian government and with international help and assistance, Cambodia has seen some major and continuous improvements in the health profile of its population since the 1980s, with a steadily rising life expectancy.
Bangladesh is one of the most populous countries in the world, as well as having one of the fastest growing economies in the world. Consequently, Bangladesh faces challenges and opportunities in regards to public health. A remarkable metamorphosis has unfolded in Bangladesh, encompassing the demographic, health, and nutritional dimensions of its populace.
Malawi ranks 170th out of 174 in the World Health Organization lifespan tables; 88% of the population live on less than £2.40 per day; and 50% are below the poverty line.
There are a number risk factors for tuberculosis infection; worldwide the most important of these is HIV. Co-infection with HIV is a particular problem in Sub-Saharan Africa, due to the high incidence of HIV in these countries. Smoking more than 20 cigarettes a day increases the risk of TB by two to four times while silicosis increases the risk about 30 fold. Diabetes mellitus is also an important risk factor that is growing in importance in developing countries. Other disease states that increase the risk of developing tuberculosis are Hodgkin lymphoma, end-stage renal disease, chronic lung disease, malnutrition, and alcoholism. A person's genetics also play a role.
Even though Panama has one of the fastest growing economies in the western hemisphere, an estimated 500,000 people are in extreme poverty. Panama has major socioeconomic and health inequalities between the country’s urban and rural populations. The indigenous population lives in more disadvantaged conditions and experiences greater vulnerability in health. In general, the population living in more marginalized areas has less service coverage and less access to health care.
Life expectancy in Nicaragua at birth was 72 years for men and 78 for women in 2016. While communicable diseases such as dengue, chikungunya, and Zika continue to persist as national health concerns, there is a rising public health threat of non-communicable diseases such as diabetes, cardiovascular disease, and cancer, which were diseases previously thought to be more relevant and problematic for more developed nations. Additionally, in the women's health sector, high rates of adolescent pregnancy and cervical cancer continue to persist as national concerns.
The Kigali Declaration on Neglected Tropical Diseases is a global health project that aims to mobilise political and financial resources for the control and eradication of infectious diseases, the so-called neglected tropical diseases due to different parasitic infections. Launched by the Uniting to Combat Neglected Tropical Diseases on 27 January 2022, it was the culmination and join commitment declared at the Kigali Summit on Malaria and Neglected Tropical Diseases (NTDs) hosted by the Government of Rwanda at its capital city Kigali on 23 June 2022.