Clinical Updates
24 April 2006
Chikungunya virus - Update
La Réunion
Since the outbreak of chikungunya virus (CHIKV) infection began on La Réunion in March 2005, 3,624 cases have been notified through the sentinel surveillance network of physicians. Since the peak of the outbreak during the week of 30 January to 5 February 2006 the number of cases reported weekly has been declining. During the week of 3 to 9 April 2006, 47 cases were reported, compared to over 700 per week during the peak of the outbreak [1].
Mathematical modelling of the outbreak suggests that a total of 241,000 people may have been infected with CHIKV, 3,100 of which during the week of 3 to 9 April 2006 [1].
Since the beginning of the outbreak, there have been 41 confirmed cases in neonates. 123 cases of severe CHIKV requiring hospitalisation and life support have also been confirmed, and CHIKV infection has been noted on 189 death certificates. Most of the deaths were in the elderly (median age 78 years) and further investigation is needed to determine the exact role of CHIKV infection in these deaths [1].
Other countries
Since the beginning of 2006 other countries in the south west Indian Ocean have reported cases of CHIKV. In Mayotte there have been 5,339 suspected cases and 52 confirmed hospitalised cases. During the week of 3 to 9 April 2006, 430 suspected cases were reported [2]. In the Seychelles, 8,818 suspected cases were reported between 1 January and 26 February 2006 [3]. The weekly incidence is now declining with 158 cases reported between 29 March and 2 April 2006 [4]. As of 14 April 2006, eight cases of CHIKV have been confirmed on the island of Anjouan, the first cases in the Comoros islands since the beginning of this outbreak [4]. Cases of CHIKV have also been reported in Mauritius and Madagascar [5].
On 17 March 2006 the World Health Organization confirmed outbreaks of CHIKV in the Indian states of Andhra Pradesh and Maharashtra [3, 5]. There have also been reports of CHIKV infection in the Indian states of Karnataka [6] and Orrisa [4]. Two hundred cases of CHIKV have been reported in Perak State, Malaysia [4].
Imported cases
As of 28 February 2006, France has reported 307 cases of imported CHIKV infection in travellers returning from La Réunion and other islands in the south west Indian Ocean [7]. Germany, Switzerland, Italy and Norway have also reported imported cases [8] and there have been reports of imported cases in Hong Kong [9] and French Guiana [10].
Since 1 December 2005 the UK has reported 2 confirmed cases of CHIKV in travellers returning from Mauritius and 7 suspected cases in travellers returning from Mauritius, the Seychelles and Madagascar [11].
Health professionals who evaluate returned travellers for suspected chikungunya virus infection can find information about submitting samples from potential cases at the HPA Special Pathogens Reference Unit website: http://www.hpa.org.uk/srmd/other_ref_labs/spru.htm
Advice to travellers
Information about CHIKV infection can be found in the NaTHNaC clinical update of 7 February 2006 [12].
There is no vaccine available to protect against CHIKV. Travellers to affected areas are advised to take insect bite precautions, particularly during daylight hours when the vector mosquitoes are active.
References
1. Institute de Veille Sanitaire. Epidemie de Chikungunya á La Réunion, Point au 13 Avril 2006. [cited 19 April 2006] Available at: http://www.invs.sante.fr/presse/2006/le_point_sur/chikungunya
_ reunion_140406/chikungunya_s14.pdf
2. Institute de Veille Sanitaire. Chikungunya a Mayotte, Point epidemiologique hebdomadaire pour le semain 14. [cited 19 April 2006] Available at: http://www.invs.sante.fr/presse/2006/le_point_sur/chikungunya
_ mayotte_140406/chikungunya_mayotte_s14.pdf
3. World Health Organization. Chikungunya in La Réunion (France), Mayotte Maurice, Seychelles, and India, 17 March 2006 [cited 19 April 2006] Available at: http://www.who.int/csr/don/2006_03_17/en/index.html
4. Institute de Veille Sanitaire. Epidemie de Chikungunya á La Réunion / Océan indien, Point de situation au 14 Avril 2006. [cited 19 April 2006] Available at: http://www.invs.sante.fr/display/?doc=presse/2006/le_point_sur
/chikungunya_140406/index.html
5. NaTHNaC. Chikungunya update. 24 March 2006. [Cited 19 April 2006] Available at: http://www.NaTHNaC.org/pro/clinical_updates/chik_240306.htm
6. ProMED mail. Chikungunya - Indian Ocean Update (15): India, 8 April 2006, [cited 19 April 2006] Available at: http://www.promedmail.org/pls/promed/f?p=2400:1001:475273
6922642189634::NO::F2400_P1001_BACK_PAGE,F2400_P10
7. Institute de Veille Sanitaire. Cas de chikungunya importés en métropole, Avril 2005 - Février 2006. [cited 19 April 2006] Available at: http://www.invs.sante.fr/presse/2006/le_point_sur/chikungunya
_cas_importes_070406/chikungunya_cas_importes_060406.p
8. Editorial Team, Pfeffer M, Löscher T. Cases of Chikungunya imported into Europe. Eurosurveillance Weekly, 2006; 11 (3). Available at: http://www.eurosurveillance.org/ew/2006/060316.asp#2
9. ProMED mail. Chikungunya - French Guiana EX Madagascar, 16 March 2006, [cited 19 April 2006] Available at: http://www.promedmail.org/pls/promed/f?p=2400:1001:112976
29023117869368::NO::F2400_P1001_BACK_PAGE,F2400_P1
10. ProMED mail. Chikungunya - China (Hong Kong) EX Mauritus, 2 April 2006, [cited 19 April 2006] Available at: http://www.promedmail.org/pls/promed/f?p=2400:1001:387909
976630851829::NO::F2400_P1001_BACK_PAGE,F2400_P100
11. Chikungunya virus in travellers to the Indian Ocean. CDR Weekly. 16 (16), 21 April 2006. Serial online. Accessed 24 April 2006. Available at: http://www.hpa.org.uk/cdr/pages/news.htm#Chikungunya
12. NaTHNaC. Chikungunya virus - Réunion, Mauritius and Seychelles. 7 February 2006. [cited 19 April 2006] Available at: http://www.NaTHNaC.org/pro/clinical_updates/chik_070206.htm
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