Tropical diseases are

disease A disease is a particular abnormal condition that adversely affects the structure or function (biology), function of all or part of an organism and is not immediately due to any external injury. Diseases are often known to be medical condi ...

s that are prevalent in or unique to tropical and

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones immediately to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Ge ...

regions. The diseases are less prevalent in

temperate climate In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ra ...

s, due in part to the occurrence of a cold season, which controls the insect population by forcing

hibernation Hibernation is a state of minimal activity and metabolic reduction entered by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It is mos ...

. 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 The British Raj ( ; from Hindustani language, Hindustani , 'reign', 'rule' or 'government') was the colonial rule of the British The Crown, Crown on the Indian subcontinent, * * lasting from 1858 to 1947. * * It is also called Crown rule ...

. Insects such as mosquitoes and flies are by far the most common disease carrier, or

vector Vector most often refers to: * Euclidean vector, a quantity with a magnitude and a direction * Disease vector, an agent that carries and transmits an infectious pathogen into another living organism Vector may also refer to: Mathematics a ...

. These insects may carry a

parasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted str ...

bacterium Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the ...

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. Human exploration of tropical rainforests, deforestation, rising immigration and increased international air travel and other tourism to tropical regions has led to an increased incidence of such diseases to non-tropical countries. Of particular concern is the

habitat loss Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

of reservoir host species.

Health programmes

In 1975 the Special Programme for Research and Training in Tropical Diseases (TDR) was established to focus on neglected infectious diseases which disproportionately affect poor and marginalized populations in developing regions of Africa, Asia, Central America and North South America. It was established at the

World Health Organization The World Health Organization (WHO) is a list of specialized agencies of the United Nations, specialized agency of the United Nations which coordinates responses to international public health issues and emergencies. It is headquartered in Gen ...

, which is the executing agency, and is co-sponsored by the United Nations Children's Fund,

United Nations Development Programme The United Nations Development Programme (UNDP) is a United Nations agency tasked with helping countries eliminate poverty and achieve sustainable economic growth and human development. The UNDP emphasizes on developing local capacity towar ...

, the

World Bank The World Bank is an international financial institution that provides loans and Grant (money), grants to the governments of Least developed countries, low- and Developing country, middle-income countries for the purposes of economic development ...

and the

. TDR's vision is to foster an effective global research effort on infectious

diseases of poverty Diseases of poverty, also known as poverty-related diseases (PRDs), 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 i ...

in which disease endemic countries play a pivotal role. It has a dual mission of developing new tools and strategies against these diseases, and to develop the research and leadership capacity in the countries where the diseases occur. The TDR secretariat is based in Geneva, Switzerland, but the work is conducted throughout the world through many partners and funded grants. Some examples of work include helping to develop new treatments for diseases, such as ivermectin for onchocerciasis (river blindness); showing how packaging can improve use of artemesinin-combination treatment (ACT) for malaria; demonstrating the effectiveness of bednets to prevent mosquito bites and malaria; and documenting how community-based and community-led programmes increases distribution of multiple treatments
TDR history
The current TDR disease portfolio includes the following entries: :^† :^‡

Other neglected tropical diseases

Additional

neglected tropical diseases 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, bacteri ...

include: Some tropical diseases are very rare, but may occur in sudden epidemics, such as the

Ebola Ebola, also known as Ebola virus disease (EVD) and Ebola hemorrhagic fever (EHF), is a viral hemorrhagic fever in humans and other primates, caused by ebolaviruses. Symptoms typically start anywhere between two days and three weeks after in ...

hemorrhagic fever,

Lassa fever Lassa fever, also known as Lassa hemorrhagic fever, is a type of viral hemorrhagic fever caused by the Lassa virus. Many of those infected by the virus asymptomatic, do not develop symptoms. When symptoms occur they typically include fever, wea ...

and the

Marburg virus Marburg virus (MARV) is a hemorrhagic fever virus of the '' Filoviridae'' family of viruses and a member of the species '' Marburg marburgvirus'', genus '' Marburgvirus''. It causes Marburg virus disease in primates, a form of viral hemorrhag ...

. There are hundreds of different tropical diseases which are less known or rarer, but that, nonetheless, have importance for

public health Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the de ...

Relation of climate to tropical diseases

The so-called "exotic" diseases in the tropics have long been noted both by travelers, explorers, etc., as well as by physicians. One obvious reason is that the hot climate present during all the year and the larger volume of rains directly affect the formation of breeding grounds, the larger number and variety of

natural reservoir In Infection, infectious disease ecology and epidemiology, a natural reservoir, also known as a disease reservoir or a reservoir of infection, is the population of organisms or the specific environment in which an infectious pathogen naturally li ...

s and animal diseases that can be transmitted to humans (

zoonosis A zoonosis (; plural zoonoses) or zoonotic disease is an infectious disease of humans caused by a pathogen (an infectious agent, such as a virus, bacterium, parasite, fungi, or prion) that can jump from a non-human vertebrate to a human. When ...

), the largest number of possible insect vectors of diseases. It is possible also that higher temperatures may favor the replication of pathogenic agents both inside and outside biological organisms. Socio-economic factors may be also in operation, since most of the poorest nations of the world are in the tropics. Tropical countries like Brazil, which have improved their socio-economic situation and invested in

hygiene Hygiene is a set of practices performed to preserve health. According to the World Health Organization (WHO), "Hygiene refers to conditions and practices that help to maintain health and prevent the spread of diseases." Personal hygiene refer ...

and the combat of transmissible diseases have achieved dramatic results in relation to the elimination or decrease of many

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

tropical diseases in their territory.

Climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...

global warming Present-day climate change includes both global warming—the ongoing increase in global average temperature—and its wider effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes ...

caused by the

greenhouse effect The greenhouse effect occurs when greenhouse gases in a planet's atmosphere insulate the planet from losing heat to space, raising its surface temperature. Surface heating can happen from an internal heat source (as in the case of Jupiter) or ...

, and the resulting increase in global temperatures, are possibly causing tropical diseases and vectors to spread to higher altitudes in mountainous regions, and to higher latitudes that were previously spared, such as the Southern United States, the Mediterranean area, etc. For example, in the Monteverde cloud forest of Costa Rica, global warming enabled Chytridiomycosis, a tropical disease, to flourish and thus force into decline amphibian populations of the Monteverde Harlequin frog. Here, global warming raised the heights of orographic cloud formation, and thus produced cloud cover that would facilitate optimum growth conditions for the implicated pathogen, B. dendrobatidis.

Role of human activities in the spread of tropical diseases

Human activities, particularly those driving climate change, are significantly influencing the spread and geographical range of tropical diseases. The burning of fossil fuels, deforestation, industrial agriculture, and urbanization release large amounts of greenhouse gases into the atmosphere, raising global temperatures and altering weather patterns. These environmental changes, such as increased rainfall, higher temperatures, and more frequent extreme weather events, create more favorable conditions for disease vectors like mosquitoes, which transmit diseases such as malaria, dengue, and Zika. In many cases, this has expanded the reach of tropical diseases into regions that were previously unaffected, including higher altitudes and temperate zones. Additionally, human-driven habitat destruction, such as the clearing of forests and wetlands, disrupts natural reservoirs and increases human-wildlife contact, further elevating the risk of zoonotic diseases crossing into human populations. As climate change continues, these activities will likely exacerbate the public health burden, especially in low-income regions that are most vulnerable to both the impacts of climate change and the diseases it helps spread.

Prevention and treatment

Tropical-cluster diseases world map - DALY - WHO2002

Vector-borne diseases

Vectors are living organisms that pass disease between humans or from animal to human. The vector carrying the highest number of diseases is the mosquito, which is responsible for the tropical diseases dengue and malaria. Many different approaches have been taken to treat and prevent these diseases. NIH-funded research has produced genetically modify mosquitoes that are unable to spread diseases such as malaria. An issue with this approach is global accessibility to genetic engineering technology; Approximately 50% of scientists in the field do not have access to information on genetically modified mosquito trials being conducted. Other prevention methods include: * Draining wetlands to reduce populations of insects and other

s, or introducing natural predators of the vectors. * The application of

insecticide Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, i ...

s and/or

insect repellent An insect repellent (also commonly called "bug spray" or "bug deterrent") is a substance applied to the skin, clothing, or other surfaces to discourage insects (and arthropods in general) from landing or climbing on that surface. Insect repellent ...

s to strategic surfaces such as clothing, skin, buildings, insect habitats, and

bed net A mosquito net is a type of meshed curtain or cloth that is circumferentially draped over a bed or a sleeping area to offer the sleeper barrier protection against bites and stings from mosquitos, flies, and other pest insects, and thus ag ...

s. * The use of a

mosquito net A mosquito net is a type of meshed curtain or cloth that is circumferentially draped over a bed or a sleeping area to offer the sleeper barrier protection against bites and stings from mosquitos, flies, and other pest insects, and thus a ...

over a bed (also known as a "bed net") to reduce nighttime transmission, since certain species of tropical

mosquito Mosquitoes, the Culicidae, are a Family (biology), family of small Diptera, flies consisting of 3,600 species. The word ''mosquito'' (formed by ''Musca (fly), mosca'' and diminutive ''-ito'') is Spanish and Portuguese for ''little fly''. Mos ...

es feed mainly at night.

Community approaches

Assisting with economic development in endemic regions can contribute to prevention and treatment of tropical diseases. For example, microloans enable communities to invest in health programs that lead to more effective disease treatment and prevention technology. Educational campaigns can aid in the prevention of various diseases. Educating children about how diseases spread and how they can be prevented has proven to be effective in practicing preventative measures. Educational campaigns can yield significant benefits at low costs.

Innovative approaches

Recent advancements in vector control technologies are proving effective in reducing the transmission of mosquito-borne diseases like malaria, dengue, and Zika. Genetically modified (GM) mosquitoes, such a
Oxitec's mosquitoes
which prevent females from surviving to adulthood, have demonstrated over a 90% reduction in mosquito populations in field trials in Brazil. Another promising approach is the use of

Wolbachia ''Wolbachia'' is a genus of gram-negative bacteria infecting many species of arthropods and filarial nematodes. The symbiotic relationship ranges from parasitism to obligate mutualism. It is one of the most common parasitic microbes of arthrop ...

bacteria, which renders mosquitoes resistant to the dengue virus. A trial in

Yogyakarta Yogyakarta is the capital city of the Special Region of Yogyakarta in Indonesia, in the south-central part of the island of Java. As the only Indonesian royal city still ruled by Hamengkubuwono, a monarchy, Yogyakarta is regarded as an importan ...

, Indonesia, showed a 77% reduction in symptomatic dengue cases in areas with Wolbachia-infected mosquitoes. Additionally
integrated vector management (IVM)
which combines biological controls, insecticides, and public education, has proven successful in reducing the transmission of arboviruses. These strategies offer more sustainable and eco-friendly solutions for controlling mosquito populations and preventing disease spread.

Other approaches

* Use of

water well A well is an excavation or structure created on the earth by digging, driving, or drilling to access liquid resources, usually water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers. The ...

s, and/or

water filtration A water filter removes impurities by lowering contamination of water using a fine physical barrier, a chemical process, or a biological process. Filters cleanse water to different extents, for purposes such as: providing agricultural irrigation, ...

, water filters, or

water treatment Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, ...

with water tablets to produce drinking water free of parasites. *

Sanitation Sanitation refers to public health conditions related to clean drinking water and treatment and disposal of human excreta and sewage. Preventing human contact with feces is part of sanitation, as is hand washing with soap. Sanitation systems ...

to prevent transmission through human waste. * Development and use of

vaccine A vaccine is a biological Dosage form, preparation that provides active acquired immunity to a particular infectious disease, infectious or cancer, malignant disease. The safety and effectiveness of vaccines has been widely studied and verifi ...

s to promote disease

immunity Immunity may refer to: Medicine * Immunity (medical), resistance of an organism to infection or disease * ''Immunity'' (journal), a scientific journal published by Cell Press Biology * Immune system Engineering * Radiofrequence immunity ...

. * Pharmacologic treatment (to treat disease after infection or infestation).

References

External links

WHO Neglected Tropical Diseases

WHO Operational research in tropical and other communicable diseases
* European Bioinformatics Institute
open source drug discovery

Drugs for Neglected Diseases Initiative

Tropical diseases
from Maya Paradise, The Guatemala Information Web Site
American Society for Tropical Medicine and Hygiene

U.S.

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respo ...

Travelers' Health
– National Center for Infectious Diseases –

Centers for Disease Control and Prevention The Centers for Disease Control and Prevention (CDC) is the National public health institutes, national public health agency of the United States. It is a Federal agencies of the United States, United States federal agency under the United S ...

Tropicology Library
In Portuguese.
'Conquest and Disease or Colonisation and Health'
lecture by Professor Frank Cox on the history of tropical disease, given at

Gresham College Gresham College is an institution of higher learning located at Barnard's Inn Hall off Holborn in Central London, England that does not accept students or award degrees. It was founded in 1597 under the Will (law), will of Sir Thomas Gresham, ...

, 17 September 2007 (available for download as video and audio files, as well as a text file). * {{DEFAULTSORT:Tropical Disease Infectious diseases Global health

Health programmes

Other neglected tropical diseases

Relation of climate to tropical diseases

Role of human activities in the spread of tropical diseases

Prevention and treatment

Vector-borne diseases

Community approaches

Innovative approaches

Other approaches

See also

References

Further reading

Books

Journals

Websites

External links