Chikungunya

Chikungunya total guide

Chikungunya a viral disease transmitted to humans by the infected mosquitoes. It causes fever and arthralgia (severe joint pain). Other symptoms are myalgia, headache, nausea, fatigue and rash.
Joint pain is often debilitating and of varying duration.
This disease has some clinical signs in common with dengue and Zika virus disease, which can lead to misdiagnosis in areas where these diseases coexist.
There is no cure for this disease. The treatment is essentially symptomatic.
The fact that mosquito breeding sites are close to homes is a serious risk factor for chikungunya.
The disease is found in Africa, Asia and the Indian subcontinent. A major outbreak, however, occurred in 2015 in several countries in the Region of the Americas.
Chikungunya is a viral mosquito-borne disease first described during an outbreak in southern Tanzania in 1952. It is an alphavirus of the family Togaviridae. The name “chikungunya” comes from a verb in the kimakonde language meaning “to become twisted” which describes the hunched appearance of those who suffer from joint pain.The virus can cause an acute, subacute or chronic illness.

Signs and symptoms Chikungunya

Chikungunya is characterized by the sudden onset of fever often accompanied by arthralgia. Other common signs and symptoms include myalgia, headache, nausea, fatigue, and rash. Arthralgia is often disabling, but usually disappears after a few days or weeks. Most patients recover completely, but in some cases arthralgia may persist for months or even years.

There have been occasional reports of ocular, neurological and cardiac complications, as well as gastrointestinal pain. Serious complications are not common, but in the elderly the disease can contribute to the cause of death. The symptoms are often mild in those infected and the infection may go unnoticed or misdiagnosed in areas where dengue fever is prevalent.
Transmission
Chikungunya has been identified in some sixty countries in Asia, Africa, Europe and the Americas.

The virus is transmitted from one human being to another by the bite of infected female mosquitoes. The offending mosquitoes are most often Aedes aegypti and Aedes albopictus, 2 species that can also transmit other viruses, including dengue fever. These mosquitoes are likely to bite during the day, although their maximum activity is mainly early in the morning and late afternoon. Both species bite outside, but Ae. Aegypti is also willing to do so indoors.

The disease usually occurs between 4 and 8 days after the bite by an infected mosquito, but the range can range from 2 to 14 days.

Diagnostic Chikungunya

Several diagnostic methods can be implemented. Serological tests, such as simple immunoenzymatic tests (ELISA), can confirm the presence of anti-chikungunya IgM and IgG antibodies. IgM antibody levels are highest three to five weeks after the onset of the disease and persist for about two months. The virus can be isolated from the blood during the first days of infection.

Various reverse transcriptase gene amplification (RT-PCR) techniques are available but their sensitivity is variable. Some are suitable for clinical diagnosis. RT-PCR products from clinical samples can also be used for gene typing of the virus, allowing comparisons with virus samples from different geographical sources. Samples collected during the first week after onset of symptoms should be analyzed using both serological and virological techniques (RT-PCR).

Treatment Chikungunya
There is no specific medicine that can cure the disease. The main purpose of treatment is to reduce symptoms, including arthralgia, with antipyretics, analgesics, and optimal fluid intake.

Prevention and fight Chikungunya
The presence of vector mosquito breeding sites near residential areas is a serious risk factor for chikungunya and other diseases transmitted by these species. Prevention and control rely to a large extent on reducing the number of natural and artificial containers containing water that promote mosquito breeding. This requires the mobilization of affected communities. During outbreaks, insecticides can be sprayed to kill mosquitoes, applied to surfaces in and around containers where mosquitoes settle, and by treating the water contained in these containers to kill larvae. .

To protect yourself during outbreaks of chikungunya, it is recommended to wear clothing covering the body as much as possible and apply a repellent on the exposed parts or on the clothes, according to the instructions that accompany the product. The repellents must contain DEET (N, N-diethyl-3-methylbenzamide), IR3535 (3- [N-acetyl-N-butyl] -aminopropionic acid ethyl ester) or icaridine (1 piperidinecarboxylic acid, 2- (2-hydroxyethyl) -1-methylpropyl ester). For those who sleep during the day, especially young children or the sick or elderly, insecticide-treated mosquito nets provide good protection. Mosquito coils or other insecticide sprays can also reduce bites inside buildings.

People traveling in risk areas should take basic precautions such as using repellents, wearing long-sleeved clothing and trousers, and checking that the rooms are equipped with mosquito nets to prevent mosquitoes from entering.

Outbreaks Chikungunya

Chikungunya is present in Africa, Asia and the Indian subcontinent. Human infections in Africa have remained at fairly low levels for a number of years, but in 1999-2000 a major outbreak occurred in the Democratic Republic of the Congo and in 2007 an outbreak occurred in Gabon.

From February 2005, a large outbreak of chikungunya occurred in the Indian Ocean Islands. A large number of cases imported into Europe were attributed to this outbreak, mostly in 2006 when the Indian Ocean epidemic was at its height. A major outbreak of chikungunya occurred in India in 2006 and 2007. Since 2005, India, Indonesia, Maldives, Myanmar and Thailand have reported 1.9 million cases.

In 2007, transmission of the disease was reported for the first time in Europe, during a localized outbreak in northeastern Italy, during which 197 cases were recorded, which confirmed that outbreaks due to mosquito Ae. Albopictus could very well occur in Europe.

In December 2013, France reported 2 laboratory-confirmed autochthonous (indigenous) cases of chikungunya in the French part of the Antillean island of Saint-Martin. Since then, local transmission has been confirmed in more than 43 countries and territories in the Americas. This was the first documented indigenous transmission chikungunya outbreak in this region.

As of April 2015, more than 1,379,788 suspected cases of chikungunya had been recorded in the Caribbean, Latin American countries and the United States of America. 191 deaths were also attributed to this disease during the same period. Canada, Mexico and the United States also reported imported cases.

On 21 October 2014, France confirmed 4 cases of chikungunya infection contracted locally in Montpellier (France). At the end of 2014, outbreaks were reported in the Pacific Islands. An outbreak of chikungunya was recorded in the Cook Islands and the Marshall Islands, while the number of cases in American Samoa, French Polynesia, Kiribati and Samoa decreased. WHO intervened following small outbreaks of chikungunya in late 2015 in the city of Dakar (Senegal) and the state of Punjab (India).

In the Americas in 2015, 693,489 suspected cases and 37,480 confirmed cases of chikungunya were reported to the Pan American Health Organization, with the WHO Regional Office bearing the heaviest burden with 356,079 cases. These figures, however, were lower than in 2014, when more than 1 million cases were recorded in this region.

In 2016, there were a total of 349,936 suspected cases and 146,914 laboratory-confirmed cases reported to the PAHO Regional Office, representing half of the burden observed the previous year. The countries reporting the most cases were Brazil (265 000 suspected cases), Bolivia and Colombia (19 000 suspected cases each). For the first time in 2016, indigenous transmission of chikungunya was reported in Argentina following an outbreak of more than 1,000 suspected cases. In the Africa Region, Kenya reported an outbreak of chikungunya with more than 1700 suspected cases. In 2017, Pakistan continues to respond to an outbreak that began in 2016.

About the vectors of the disease
Both Ae. aegypti that Ae. albopictus have been implicated in important outbreaks of chikungunya. While Ae. aegypti lives only in tropical and subtropical areas, Ae. albopictus is also found in temperate and even cold regions. In recent decades. albopictus has spread from Asia to parts of Africa, Europe and the Americas.

The species Ae. albopictus proliferates in breeding sites containing much more water than Ae. aegypti, especially in coconut shells, cocoa pods, bamboo stumps, tree cavities and rock crevices, in addition to artificial containers such as vehicle tires and saucers placed under flowerpots . albopictus in rural as well as peri-urban areas and in shaded city parks. Ae. aegypti is more closely associated with human habitation and uses indoor breeding sites, including flower vases, water tanks and concrete water tanks in bathrooms, as well as in the same outdoor artificial habitats that Ae. albopictus.

In Africa, several other mosquito vectors have been implicated in the transmission of the disease, including the A. furcifer-taylori and A. luteocephalus species. It appears that some animals, including non-primates, rodents, birds and small mammals serve as a reservoir.

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