Dengue fever in the context of "Shock (circulatory)"

In epidemiology, incidence reflects the number of new cases of a given medical condition in a population within a specified period of time.

Climate change affects human health in many ways, including an increase in heat-related illnesses and deaths, worsened air quality, the spread of infectious diseases, and health risks associated with extreme weather such as floods and storms. Rising global temperatures and changes in weather patterns are increasing the severity of heat waves and extreme weather events. These events in turn have direct and indirect impacts on human health. For example, when people are exposed to higher temperatures for longer time periods they might experience heat illness and heat-related death.

In addition to direct impacts, climate change and extreme weather events cause changes in biomes. Certain diseases that are carried and spread by living hosts such as mosquitoes and ticks (known as vectors) may become more common in some regions. Affected diseases include dengue fever and malaria. Contracting waterborne diseases such as diarrhoeal disease will also be more likely.

Rice polyculture is the cultivation of rice and another crop simultaneously on the same land. The practice exploits the mutual benefit between rice and organisms such as fish and ducks: the rice supports pests which serve as food for the fish and ducks, while the animals' excrement serves as fertiliser for the rice. The result is an additional crop, with reduced need for inputs of fertiliser and pesticides. In addition, the reduction of pests such as mosquito larvae and snails may reduce mosquito-borne diseases such as malaria and dengue fever, and snail-born parasites such as the trematodes which cause schistosomiasis. The reduction in chemical inputs may reduce environmental harms caused by their release into the environment. The increased biodiversity may reduce methane emissions from rice fields.

Some rice-animal polycultures, including rice-fish systems in China and rice-duck farming in China and Southeast Asia, have been practised for centuries, while others have been developed more recently. The use of intercropping with plants such as maize and soybean, planted on levees between rice terraces, may help to reduce rice pests such as brown planthopper.

Gangrene is a type of tissue death caused by a lack of blood supply. Symptoms may include a change in skin color to red or black, numbness, swelling, pain, skin breakdown, and coolness. The feet and hands are most commonly affected. If the gangrene is caused by an infectious agent, it may present with a fever or sepsis.

Risk factors include diabetes, peripheral arterial disease, smoking, major trauma, alcoholism, HIV/AIDS, frostbite, influenza, dengue fever, malaria, chickenpox, plague, hypernatremia, radiation injuries, meningococcal disease, Group B streptococcal infection and Raynaud's syndrome. It can be classified as dry gangrene, wet gangrene, gas gangrene, internal gangrene, and necrotizing fasciitis. The diagnosis of gangrene is based on symptoms and supported by tests such as medical imaging.

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 repellents help prevent and control the outbreak of insect-borne (and other arthropod-bourne) diseases such as malaria, Lyme disease, dengue fever, bubonic plague, river blindness, and West Nile fever. Pest animals commonly serving as vectors for disease include insects such as flea, fly, and mosquito; and ticks (arachnids).

Some insect repellents are insecticides (bug killers), but most simply discourage insects and send them flying or crawling away.

Aedes aegypti (/ˈiːdiːz eɪˈdʒɪpti/; US: /eɪdz -, ˈeɪdiːz -/; from Ancient Greek αηδής (aēdḗs) 'unpleasant' and Latin aegyptī 'Egyptian') – sometimes called the Egyptian mosquito, dengue mosquito, or yellow fever mosquito – is a mosquito that spreads diseases such as dengue fever, yellow fever, and chikungunya. The mosquito can be recognized by black and white markings on its legs and a marking in the form of a lyre on the upper surface of its thorax. The mosquito is native to north Africa, but is now a common invasive species that has spread to tropical, subtropical, and temperate regions throughout the world.

A rice-fish system is a rice polyculture, a practice that integrates rice agriculture with aquaculture, most commonly with freshwater fish. It is based on a mutually beneficial relationship between rice and fish in the same agroecosystem. The system was recognized by the FAO in 2002 as one of the first Globally Important Agricultural Heritage Systems.

The benefits of rice-fish systems include increased rice yield, the production of an additional (fish) crop on the same land, diversification of farm production, increased food security, and reduced need for inputs of fertilizer and pesticide. Because fish eat insects and snails, the systems may reduce mosquito-borne diseases such as malaria and dengue fever, and snail-born parasites such as the trematodes which cause schistosomiasis. The reduction in chemical inputs may reduce environmental harms caused by their release into the environment. The increased biodiversity may reduce methane emissions from rice fields.

Dengue virus (DENV) is the cause of dengue fever. It is a mosquito-borne, single positive-stranded RNA virus of the family Flaviviridae; genus Orthoflavivirus. Four serotypes of the virus have been found, and a reported fifth has yet to be confirmed, all of which can cause the full spectrum of disease. Nevertheless, the mainstream scientific community's understanding of dengue virus may be simplistic as, rather than distinct antigenic groups, a continuum appears to exist. This same study identified 47 strains of dengue virus. Additionally, coinfection with and lack of rapid tests for Zika virus and chikungunya complicate matters in real-world infections.

Dengue virus has increased dramatically within the last 20 years, becoming one of the worst mosquito-borne human pathogens that tropical countries have to deal with. Estimates published in 2013 indicate that as many as 390 million infections occur each year, and many dengue infections are increasingly understood to be asymptomatic or subclinical.