Chikungunya By Edidiong Umoren 1967

Contents What is chikungunya The virus Historical background Etymology and origin of the name Epidemiology Transmission Clinical features Symptoms Diagnosis Treatment Prevention References.

What is Chikungunya Chikungunya virus is transmitted to people by mosquitoes. Chikungunya virus (CHIKV) is an arthropod- borne virus, of the genus Alphavirus, that is transmitted to humans by virus-carrying Aedes mosquitoes. Aedes mosquitoes is a genus of mosquitoes that were originally found in tropical and subtropical regions of the world but are now found in areas like Antarctica.

Virus Causative agent is an RNA – VIRUS Class – Arbor Virus (Arthropod Borne) Chikungunya virus is from the family togaviridae, genus alpha virus. The infections mostly occur during the rainy season when there is increased densities of the mosquito. Similar to Semliki Forest Viruses (SFV) in Africa and Asia.

Historical background There are historical accounts of epidemics of fever, arthralgias/arthritis, and rash, resembling what is now called “Chikungunya fever” dating back to 1824 from India and elsewhere. Chikungunya fever was first described in 1952,following an outbreak on the Makonde Plateau, along the border between Tanganyika and Mozambique.

Etymology and Origin of the name For a long time, it was erroneously reported that the word “Chikungunya” was derived from the “Swahili” language both in lay press and the media and reputed medical journals. The word “Chikungunya” is derived from the Makonde language, spoken by an ethnic group in south- east Tanzania and northern Mozambique from the root verb “kungunyala”, meaning “to dry up or become contorted,” and signifies the cause of a contortion or folding

. Literally, the word “Chikungunya” translates to “that which bends up” in reference to the stooped posture developed due to the rheumatological manifestations of the disease. In Congo, it has been called “buka-buka”, meaning “broken-broken” once again reflecting the incapacitating arthralgias that are common acute manifestations of Chikungunya fever.

Epidemiology Following the report from Tanganyika in 1952,Chikungunya epidemics have been reported from several parts of the world including Africa, Asia, and elsewhere. In South-East Asia, epidemics have been documented in India, Pakistan, Sri Lanka, Myanmar, Thailand, Indonesia, the Philippines, Cambodia, Vietnam, Hong Kong, and Malaysia. Since 2003, there have been outbreaks in the islands of the Pacific Ocean, including Madagascar, Comoros, Mayotte the Seychelles, and Mauritius, and the Reunion Island (French overseas district in the Indian Ocean)

Transmission Chikungunya virus is transmitted to people through mosquito bites. Mosquitoes become infected when they feed on a person already infected with the virus. Infected mosquitoes can then spread the virus to other people through bites. Chikungunya virus is most often spread to people by Aedes aegypti and Aedes albopictus mosquitoes. These are the same mosquitoes that transmit dengue virus. They bite mostly during the daytime.

Chikungunya virus is transmitted rarely from mother to newborn around the time of birth. The virus could be spread through a blood transfusion.

Clinical features Incubation is normally 3-12 days. Fevers may rise 103degrees to 104 degrees with rigors. Viremia leads to fever and fever leads to an increase release of interferons (interferons are proteins made and released by host cells in response to the presence of pathogens such as viruses, bacteria, parasites or tumor cells).

Symptoms The symptoms of chikungunya appear 4-7 days after you have been bitten by the infected mosquitoe. symptoms include: 1. High fever (40°C/ 104°F)(i.e biphasic with remission after 1-6 days) 2. Joint pain (lower back, ankle, knees, wrists or phalanges) 3. Joint swelling 4. Rash

5. Headache 6. Muscle pain 7. Nausea 8. Fatigue 9. Photophobia 10. Bleeding gums 11. Epistaxis 12.Maleana 13.Conjuntivitis 14.lymphadenopathy

People at risk for more severe disease include newborns infected around the time of birth, older adults (≥65 years), and people with medical conditions such as high blood pressure, diabetes, or heart disease. Although dengue fever and CHIK virus are almost similar they have some differences.

Skin rash in dengue

Skin rash in CHIKV

Rare manifestations A petechial or maculo papular rash usually involving the limbs may occur. Hemorrhage is rare Nasal blotchy erythema, freckle-like pigmentation over centro-facial area, Flagellate pigmentation on face and extremities Lichenoid eruption and hyper pigmentation in exposed areas

Petechaie on the leg

Flagellate pigmentation

Diagnosis Common laboratory tests for chikungunya include RT-PCR, virus isolation, and serological tests. 1. Virus isolation provides the most definitive diagnosis, but takes one to two weeks for completion and must be carried out in biosafety level 3 laboratory.The technique involves exposing specific cell lines to samples from whole blood and identifying chikungunya virus-specific responses.

2.RT-PCR using nested primer pairs is used to amplify several chikungunya-specific genes from whole blood. Results can be determined in one to two days. 3.Serological diagnosis requires a larger amount of blood than the other methods, and uses an ELISA assay to measure chikungunya-specific IgM levels. Results require two to three days, and false positives can occur with infection via other related viruses, such as o'nyong'nyong virus and Semliki Forest virus

Treatment There is no cure for chikungunya, and no vaccine to prevent it, so treatment is focused on relieving the symptoms. An infected person needs to rest, drink lots of fluids, and take medicines like ibuprofen, naproxen, or acetaminophen to relieve fever and pain until the symptoms fade.

Prevention Use air conditioning or window/door screens to keep mosquitoes outside. If you are not able to protect yourself from mosquitoes inside your home or hotel, sleep under a mosquito bed net. Help reduce the number of mosquitoes outside your home or hotel room by emptying standing water from containers such as flowerpots or buckets. When weather permits, wear long-sleeved shirts and long pants. Use insect repellents

references viral/other_arboviral_chikungunya/en/ viral/other_arboviral_chikungunya/en/