Yellow fever is a viral disease of typically short duration. In most cases, symptoms include fever, chills, loss of appetite, nausea, muscle pains – particularly in the back – and headaches. Symptoms typically improve within five days. In about 15% of people, within a day of improving the fever comes back, abdominal pain occurs, and liver damage begins causing yellow skin. If this occurs, the risk of bleeding and kidney problems is increased.
Dengue fever is a mosquito-borne tropical disease caused by the dengue virus. Symptoms typically begin 3 to 14 days after infection. These may include a high fever, headache, vomiting, muscle and joint pains, and a characteristic skin itching and skin rash. Recovery generally takes two to seven days. In a small proportion of cases, the disease develops into a more severe dengue hemorrhagic fever, resulting in bleeding, low levels of blood platelets and blood plasma leakage, or into dengue shock syndrome, where dangerously low blood pressure occurs.
Incubation period is the time elapsed between exposure to a pathogenic organism, a chemical, or radiation, and when symptoms and signs are first apparent. In a typical infectious disease, the incubation period signifies the period taken by the multiplying organism to reach a threshold necessary to produce symptoms in the host.
Aedes albopictus, from the mosquito (Culicidae) family, also known as the (Asian) tiger mosquito or forest mosquito, is a mosquito native to the tropical and subtropical areas of Southeast Asia. In the past few centuries, however, this species has spread to many countries through the transport of goods and international travel. It is characterized by the white bands on its legs and body.
Chikungunya is an infection caused by the Chikungunya virus (CHIKV). Symptoms include fever and joint pains. These typically occur two to twelve days after exposure. Other symptoms may include headache, muscle pain, joint swelling, and a rash. Symptoms usually improve within a week; however, occasionally the joint pain may last for months or years. The risk of death is around 1 in 1,000. The very young, old, and those with other health problems are at risk of more severe disease.
Arbovirus is an informal name for any virus that is transmitted by arthropod vectors. The term arbovirus is a portmanteau word. Tibovirus is sometimes used to more specifically describe viruses transmitted by ticks, a superorder within the arthropods. Arboviruses can affect both animals and plants. In humans, symptoms of arbovirus infection generally occur 3–15 days after exposure to the virus and last three or four days. The most common clinical features of infection are fever, headache, and malaise, but encephalitis and viral hemorrhagic fever may also occur.
Aedes aegypti, the yellow fever mosquito, is a mosquito that can spread dengue fever, chikungunya, Zika fever, Mayaro and yellow fever viruses, and other disease agents. 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. This mosquito originated in Africa, but is now found in tropical, subtropical and temperate regions throughout the world.
Chikungunya is a mosquito-borne alpha virus that was first isolated after a 1952 outbreak in modern-day Tanzania. The virus has circulated in forested regions of sub-Saharan African in cycles involving nonhuman primate hosts and arboreal mosquito vectors. Phylogenetic studies indicate that the urban transmission cycle—the transmission of a pathogen between humans and mosquitoes that exist in urban environments—was established on multiple occasions from strains occurring on the eastern half of Africa in non-human primate hosts. This emergence and spread beyond Africa may have started as early as the 18th century. Currently, available data does not indicate whether the introduction of chikungunya into Asia occurred in the 19th century or more recently, but this epidemic Asian strain causes outbreaks in India and continues to circulate in Southeast Asia.
A reverse zoonosis, also known as a zooanthroponosis or anthroponosis, is a pathogen reservoired in humans that is capable of being transmitted to non-human animals.
Singapore is one of the wealthiest countries in the world, with a gross domestic product (GDP) per capita of more than $57,000. Life expectancy at birth is 82.3 and infant mortality is 2.7 per 1000 live births. The population is ageing and by 2030, 20% will be over 65. However it is estimated that about 85% of those over 65 are healthy and reasonably active. Singapore has a universal health care system.
Mosquito-borne diseases or mosquito-borne illnesses are diseases caused by bacteria, viruses or parasites transmitted by mosquitoes. Nearly 700 million people get a mosquito-borne illness each year resulting in over 725,000 deaths.
Zika virus is a member of the virus family Flaviviridae. It is spread by daytime-active Aedes mosquitoes, such as A. aegypti and A. albopictus. Its name comes from the Ziika Forest of Uganda, where the virus was first isolated in 1947. Zika virus shares a genus with the dengue, yellow fever, Japanese encephalitis, and West Nile viruses. Since the 1950s, it has been known to occur within a narrow equatorial belt from Africa to Asia. From 2007 to 2016, the virus spread eastward, across the Pacific Ocean to the Americas, leading to the 2015–2016 Zika virus epidemic.
Mayaro virus disease is a mosquito-borne zoonotic pathogen endemic to certain humid forests of tropical South America. Infection with Mayaro virus causes an acute, self-limited dengue-like illness of 3–5 days' duration. The causative virus, abbreviated MAYV, is in the family Togaviridae, and genus Alphavirus. It is closely related to other alphaviruses that produce a dengue-like illness accompanied by long-lasting arthralgia. It is only known to circulate in tropical South America.
The 2007 Yap Islands Zika virus outbreak represented the first time Zika virus had been detected outside Africa and Asia. It occurred in the Yap Islands, an island chain in the Federated States of Micronesia. Zika virus (ZIKV) is a vector-borne flavivirus in the same family as yellow fever, dengue, West Nile and Japanese encephalitis viruses.
A lethal ovitrap is a device which attracts gravid female container-breeding mosquitoes and kills them. The traps halt the insect's life cycle by killing adult insects and stopping reproduction. The original use of ovitraps was to monitor the spread and density of Aedes and other container-breeding mosquito populations by collecting eggs which could be counted, or hatched to identify the types of insects. Since its conception, researchers found that adding lethal substances to the ovitraps could control the populations of these targeted species. These traps are called lethal ovitraps. They primarily target Aedes aegypti and Aedes albopictus mosquitoes, which are the main vectors of dengue fever, Zika virus, west Nile virus, yellow fever, and chikungunya.
In October 2013, there was an outbreak of Zika fever in French Polynesia, the first outbreak of several Zika outbreaks across Oceania. With 8,723 cases reported, it was the largest outbreak of Zika fever before the outbreak in the Americas that began in April 2015. An earlier outbreak occurred on Yap Island in the Federated States of Micronesia in 2007, but it is thought that the 2013–2014 outbreak involved an independent introduction of the Zika virus from Southeast Asia. Investigators suggested that the outbreaks of mosquito-borne diseases in the Pacific from 2012 to 2014 were "the early stages of a wave that will continue for several years", particularly because of their vulnerability to infectious diseases stemming from isolation and immunologically naive populations.
The 2019–2020 dengue fever epidemic was an epidemic of the infectious disease dengue fever in several countries of Southeast Asia, including the Philippines, Malaysia, Vietnam, and Bangladesh, Pakistan, India, Thailand, Singapore, and Laos. The spread of the disease was exacerbated by falling vaccination levels in certain areas, and by a growing population of mosquitoes, which are the primary carriers of the disease, and which are able to reproduce in larger numbers where humans have littered the environment with plastic containers, which provide an ideal breeding ground for mosquitoes. Affected countries have sought to control the epidemic through increased vaccination efforts, and through efforts to control the mosquito population.
Global climate change has increased the occurrence of some infectious diseases. Those infectious diseases whose transmission is impacted by climate change include for example the vector-borne diseases dengue fever, malaria, tick-borne diseases, leishmaniasis, zika fever, chikungunya and Ebola virus disease. One of the mechanisms for increased disease transmission is that climate change is altering the geographic range and seasonality of the insects that can carry the diseases. Scientists stated a clear observation in 2022: "the occurrence of climate-related food-borne and waterborne diseases has increased ."
The dengue pandemic in Sri Lanka is part of the tropical disease dengue fever pandemic. Dengue fever is caused by Dengue virus, first recorded in the 1960s. It is not a native disease in this island. Present-day dengue has become a major public health problem. Aedes aegypti and Aedes albopictus are both mosquito species native to Sri Lanka. However, the disease did not emerge until the early 1960s. Dengue was first serologically confirmed in the country in 1962. A Chikungunya outbreak followed in 1965. In the early 1970s two type of dengue dominated in Sri Lanka: DENV-1 type1 and DENV-2 type 2. A total of 51 cases and 15 deaths were reported in 1965–1968. From 1989 onward, dengue fever has become endemic in Sri Lanka.
In the 2020 dengue outbreak in Singapore, a record-breaking number of dengue fever cases was reported in Singapore. This was part of the wider 2019–2020 dengue fever epidemic which also affected several neighbouring countries in Southeast Asia.
