Chikungunya

Chikungunya
ICD-10	A92.0
ICD-9	065.4, 066.3
DiseasesDB	32213
MeSH	D018354

Chikungunya virus
Virus classification
Group: Group IV ((+)ssRNA) Family: Togaviridae Genus: Alphavirus Species: Chikungunya virus

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Chikungunya is a relatively rare form of viral fever caused by an alphavirus that is spread by mosquito bites from Aedes aegypti mosquitoes, though recent research by the Pasteur Institute in Paris claims the virus has suffered a mutation that enables it to be transmitted by Aedes albopictus (Tiger mosquito). This was the cause of the plague in the Indian Ocean and a threat to the Mediterranean coast at present, requiring urgent meetings of health officials in the region.

==References==

Etymology

The name is derived from the Makonde word meaning "that which bends up" in reference to the stooped posture developed as a result of the arthritic symptoms of the disease. The disease was first described by Marion Robinson and W.H.R. Lumsden in 1955, following an outbreak on the Makonde Plateau, along the border between Tanganyika and Mozambique, in 1952. Chikungunya is closely related to O'nyong'nyong virus.

Linguistic confusion

According to Lumsden's initial 1955 report about the epidemiology of the disease, the term chikungunya is derived from the Makonde root verb kungunyala, meaning to dry up or become contorted. In concurrent research, Robinson glossed the Makonde term more specifically as "that which bends up." Subsequent authors apparently overlooked the references to the Makonde language and assumed that the term derived from Swahili, the lingua franca of the region. The erroneous attribution of the term as a Swahili word has been repeated in numerous print sources. Many other erroneous spellings and forms of the term are in common use including "Chicken guinea", "Chicken gunaya," and "Chickengunya".

Impact

Chikungunya is generally not fatal. However, in 2005-2006, 200 deaths were associated with chikungunya on Réunion island and a widespread outbreak in India, primarily in Tamil Nadu, Karnataka, Kerala, and Andhra Pradesh. After flood and heavy rains in Rajasthan, India in August 2006, thousands of cases were detected in Rajsamand, Bhilwara, Udaipur, and Chittorgarh districts and also in adjoining regions of Gujarat and Madhya Pradesh, and in the neighbouring country of Sri Lanka. In the southern Indian state of Kerala, 125 deaths were attributed to Chikungunya with the majority of the casualties reported in the district of Alapuzha, primarily in Cherthala. In December 2006, an outbreak of 3,500 confirmed cases occurred in Maldives, and over 60,000 cases in Sri Lanka, with over 80 deaths. [2]. In October 2006 more than a dozen cases of Chikungunya were reported in Pakistan. A recent outbreak of the disease during June 2007 in Pathanamthitta, Kottayam and Alappuzha districts of South Kerala, India claimed more than 50 lives. It is confirmed officially that there are 7000 confirmed Chikungunya patients in these areas. Unofficial reports suggest that more than one hundred thousand are suffering from symptoms of chikungunya.. The European Network for Diagnostics of "Imported" Viral Diseases [3] claims that new phylogenetic variants of the virus which are fatal have been identified on Réunion. [4]. In August/September 2007 some 160 people were infected in Italy's northern Ravenna region, resulting in one fatality.

Symptoms

The Aedes aegypti mosquito

The symptoms of Chikungunya include fever which can reach 39°C, (102.2°F) a petechial or maculopapular rash usually involving the limbs and trunk, and arthralgia or arthritis affecting multiple joints which can be debilitating. The symptoms could also include headache, conjunctival injection, and slight photophobia. In the present epidemic in the states of Andhra Pradesh and Tamil Nadu, India, high fever and crippling joint pain are the prevalent complaint. The fever typically lasts for two days and abruptly comes down. However, other symptoms, namely joint pain, intense headache, insomnia and an extreme degree of prostration last for a variable period, usually for about 5 to 7 days. But, patients have complained joint pains for much longer time periods depending on age of the patient. With younger patients recovering within 5 to 15 days and middle aged recovering in 1 to 2.5 months and more for old people. It has been observed that the severity of the disease as well as its duration is less in younger patients and pregnant women. No untoward effects of pregnancy is noticed following the infection.

Dermatological manifestations observed in a recent outbreak of Chikungunya fever in Southern India (Dr. Arun Inamadar, Dr. Aparna Palit, Dr.V.V. Sampagavi, Dr. Raghunath S, Dr. N.S. Deshmukh), Western India (Surat) (Western India reported by Dr. Buddhadev) and Eastern India (Puri) (Dr. Milon Mitra et al) includes the following:

• Maculopapular rash
• Nasal blotchy erythema
• Freckle-like pigmentation over centro-facial area
• Flagellate pigmentation on face and extremities
• Lichenoid eruption and hyperpigmentation in photodistributed areas
• Multiple aphthous-like ulcers over scrotum, crural areas and axilla.
• Lympoedema in acral distribution (bilateral/unilateral)
• Multiple ecchymotic spots (Children)
• Vesiculobullous lesions (infants)
• Subungual hemorrhage
• Photo Urticaria
• Acral Urticaria
• Cephalgia
• Lumbago
• Vomiting
• Epistaxis and haemetemesis

Histopathologically, pigmentary changes, maculopapular rash, lichenoid rash, aphthous-like ulcers show lymphocytic infiltration around dermal blood vessels (Inamadar et al). Pedal oedema (swelling of legs) is observed in many patients, the cause of which remains obscure as it is not related to any cardiovascular, renal or hepatic abnormalities.

Treatment

There is no specific treatment for Chikungunya. Vaccine trials were carried out in 2000, but funding for the project was discontinued and there is no vaccine currently available. A serological test for Chikungunya is available from the University of Malaya in Kuala Lumpur, Malaysia.

Chloroquine is gaining ground as a possible treatment for the symptoms associated with Chikungunya and as an antiviral agent to combat the Chikungunya virus. According to the University of Malaya, "In unresolved arthritis refractory to aspirin and nonsteroidal anti-inflammatory drugs, chloroquine phosphate (250 mg/day) has given promising results." [5] Research by Italian scientist, Andrea Savarino, and his colleagues in addition a French government press release in March 2006 [6] have added more credence to the claim that chloroquine may be effective in treating Chikungunya. The CDC fact sheet on Chikungunya advises against using Aspirin. Ibuprofen, Naproxen and other non-steroidal anti-inflammatory drugs are recommended for arthritic pain and fever.

Infected persons should limit further exposure to mosquito bites, stay indoors and under a mosquito net. Further, "supportive care with rest is preferred during the acute joint symptoms. Movement and mild exercise tend to improve stiffness and morning arthralgia, but heavy exercise may exacerbate rheumatic symptoms." [7] Arthralgia remains troublesome even after 8 months. In Andhra Pradesh patients use donkey milk as medicine.In Kerala patients have relief by honey/lime mix.Some people get relief by having turmeric in low volume. Homoeopathy claims to have successful treatment for chikungunya. As they treat on symptomatology and not the diagnosis, they claim to have many medicines successful for prevention and cure of chikungunya.

Epidemiology

Chikungunya was first described in Tanzania, Africa in 1952. The first outbreak in India was in 1963 in Kolkata(Calcutta). An outbreak of chikungunya was also discovered in Port Klang in Malaysia in 1999 affecting 27 people [8] [9]. There was an outbreak in Italy late 2007, with 160 cases.

Preventive measures

The most effective means of prevention are those that protect against any contact with the disease-carrying mosquitos. These include using insect repellent containing NNDB, DEET or permethrin, wearing long sleeves and trousers (pants), and securing screens on windows and doors. It's also important to empty stagnant water where mosquitoes breed. [10].

See also

• Dengue fever

External links

General information

• CDC factsheet on Chikungunya
• ECDC Chikungunya fact-sheet
• CDC Review of Chikungunya Virus as published in the September 2007 volume of The Journal of General Virology.
• Alphaviruses
• WHO site on disease outbreak news
• Chikungunya Research and Chikun guniya - latest publications.
• Chikungunya is not Swahili (Internet Living Swahili Dictionary)
• Chikungunya and Pregnancy
• Chikungunya and how to handle it (Mauritius)
• European Center for Disease Prevention and Control: Chikungunya Info for Travellers
• Chikungunya Infection in India and Vector Control
• Genome Microevolution of Chikungunya Viruses Causing the Indian Ocean Outbreak, NIH, July 2006.
• Chikungunya Siddha Treatment
• Realities of Chikungunya in Kerala

News reports

• Chikungunya fever epidemic in Reunion Island (FR)
• French pledge for disease island (BBC article)
• Articles on Chikungunya in Seychelles
• Madagascar hit by mosquito virus (BBC article)
• Medindia.net
• [11]
• [12]
• European network for diagnosis of imported viral diseases