[11] Once infected and symptomatic, recommendations to patients should include rest, fluids, and medications to help with fever and joint pain.

[12][13] Around 85% of people infected with the chikungunya virus experience symptoms, typically beginning with a sudden high fever above 39 °C (102 °F).

[15] Around half of those affected develop a rash, with reddening and sometimes small bumps on the palms, foot soles, torso, and face.

[15] In particularly rare cases, people may develop behavioral changes, seizures, irritation of the cerebellum or meninges, oculomotor nerve palsy, or paralysis of the eye muscles.

[15] In severe cases, affected newborns may also have issues with bleeding and blood flow and problems with heart function.

In the United States, it is classified as a category B priority pathogen,[23] and work requires biosafety level III precautions.

Transmission via infected blood products and through organ donation is also theoretically possible during times of outbreak, though no cases have yet been documented.

The adaptation of mosquitoes to the changing climate of North Africa around 5,000 years ago made them seek out environments where humans stored water.

[17] Research by the Pasteur Institute in Paris has suggested Chikungunya virus strains in the 2005–2006 Reunion Island outbreak incurred a mutation that facilitated transmission by the Asian tiger mosquito (A.

It appears that in vitro, Chikungunya virus is able to replicate in human epithelial and endothelial cells, primary fibroblasts, and monocyte-derived macrophages.

[32][34][35] The chikungunya-specific upstream components of the type-1 interferon pathway involved in the host's response to chikungunya infection are still unknown.

In the chronic phase, it is suggested that viral persistence (the inability of the body to entirely rid itself of the virus), lack of clearance of the antigen, or both, contribute to joint pain.

The inflammation response during both the acute and chronic phases of the disease results in part from interactions between the virus and monocytes and macrophages.

Cytokines may also contribute to chronic Chikungunya virus disease, as persistent joint pain has been associated with elevated levels of IL-6 and granulocyte-macrophage colony-stimulating factor (GM-CSF).

Clinically, acute onset of high fever and severe joint pain would lead to suspicion of chikungunya.

Epidemiological criteria consist of whether the individual has traveled to or spent time in an area in which chikungunya is present within the last twelve days (i.e.) the potential incubation period).

Chronic recurrent polyarthralgia occurs in at least 20% of chikungunya patients one year after infection, whereas such symptoms are uncommon in dengue.

[45] Virus isolation provides the most definitive diagnosis, but takes one to two weeks for completion and must be carried out in biosafety level III laboratories.

[46] The technique involves exposing specific cell lines to samples from whole blood and identifying Chikungunya virus-specific responses.

[46] Presently, there is no specific way to test for chronic signs and symptoms associated with Chikungunya fever although nonspecific laboratory findings such as C reactive protein and elevated cytokines can correlate with disease activity.

[citation needed] Wearing bite-proof long sleeves and trousers also offers protection, and garments can be treated with pyrethroids, a class of insecticides that often has repellent properties.

[6] Supportive care is recommended, and symptomatic treatment of fever and joint swelling includes the use of nonsteroidal anti-inflammatory drugs such as naproxen, non-aspirin analgesics such as paracetamol (acetaminophen) and fluids.

[51] Passive immunotherapy involves administration of anti-CHIKV hyperimmune human intravenous antibodies (immunoglobulins) to those exposed to a high risk of chikungunya infection.

[58] The transmission of the 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.

However, since 2005, following several decades of relative inactivity, chikungunya has re-emerged and caused large outbreaks in Africa, Asia, and the Americas.

[65] Enhanced transmission of Chikungunya virus by A. albopictus could mean an increased risk for outbreaks in other areas where the Asian tiger mosquito is present.

Lumsden[70] in a pair of 1955 papers, following an outbreak in 1952 on the Makonde Plateau, along the border between Mozambique and Tanganyika (the mainland part of modern-day Tanzania).

[72] According to the original paper by Lumsden, the term 'chikungunya' is derived from the Makonde root verb kungunyala, meaning to dry up or become contorted.

It is understood to refer to the contorted posture of people affected with severe joint pain and arthritic symptoms associated with this disease.

[73] Subsequent authors overlooked the references to the Makonde language and assumed the term to have been derived from Swahili, the lingua franca of the region.