Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link
Volume 14, Number 8—August 2008
Letter

Chikungunya-related Fatality Rates, Mauritius, India, and Reunion Island

On This Page
Article Metrics
45
citations of this article
EID Journal Metrics on Scopus

Cite This Article

To the Editor: During the epidemic of chikungunya virus infection that occurred on Reunion Island in 2005–06, we reported an overmortality corresponding to the epidemic peak, which was estimated by comparing observed and expected deaths (1). The excess was similar to the number of deaths related to chikungunya infection reported by death certificates (2). The case-fatality rate (CFR) on Reunion Island was estimated to be 1/1,000 population.

According to Beesoon et al. (3), the fatality rate attributable to chikungunya infection was much higher on Mauritius: 743 deaths in excess of expected deaths led to a CFR of ≈4.5%, with 15,760 confirmed or suspected cases for 2005 and 2006 as reported in this letter. A similar CFR of 4.9% can be calculated for the city of Ahmedabad, India, during the 2006 chikungunya epidemic (4).

This 45- to 49-fold difference could be explained by a greater severity of chikungunya infection in Mauritius or Ahmedabad that could be due to a mutating strain, differences in the preexisting conditions of patients, differences in the management of patients, or by coincident deaths in excess from other causes.

However, the most probable explanation can be attributed to the surveillance systems of chikungunya cases. On Reunion Island, surveillance was highly sensitive and relied either on active case finding or on estimates of suspected cases. Results have been assessed by iterative external studies and serosurveys, and the CFR we found is likely consistent.

If we apply this rate to Mauritius, ≈60% of the population would have contracted chikungunya infection during this epidemic. If so, the risk of epidemic resurgence could be much lower than previously expected. This point raises the need to conduct seroprevalence studies in those territories, the only way to evaluate the herd immunity level of the population.

Top

Philippe Renault*Comments to Author , Loic Josseran†, and Vincent Pierre*
Author affiliations: *Cellule Interrégionale d'Épidémiologie Réunion-Mayotte, Saint-Denis, Réunion, France; †Institut de Veille Sanitaire, Saint-Maurice, France;

Top

References

  1. Josseran L, Paquet C, Zehgnoun A, Caillere N, Le Tertre A, Solet JL, Chikungunya disease outbreak, Reunion Island.Emerg Infect Dis. 2006;12:19945.PubMed
  2. Renault P, Solet JL, Sissoko D, Balleydier E, Larrieu S, Filleul L, A major epidemic of chikungunya virus infection on Réunion Island, France, 2005–2006.Am J Trop Med Hyg. 2007;77:72731.PubMed
  3. Beesoon S, Funkhouser E, Kotea N, Spielman A, Robich RM. Chikungunya fever, Mauritius, 2006.Emerg Infect Dis. 2008;14:3378. DOIPubMed
  4. Mavalankar D, Shastri P, Bandyopadhyay T, Parmar J, Ramani KV. Increased mortality rate associated with chikungunya epidemic, Ahmedabad, India.Emerg Infect Dis. 2008;14:4125. DOIPubMed

Top

Cite This Article

DOI: 10.3201/eid1408.080201

Related Links

Top

Table of Contents – Volume 14, Number 8—August 2008

Comments

Please use the form below to submit correspondence to the authors or contact them at the following address:

Philippe Renault, Cellule interrégionale d’Épidémiologie Réunion-Mayotte, 2 bis avenue Georges Brassens, BP 50, 97408 Saint-Denis CEDEX 9, Réunion, France;

Send To

10000 character(s) remaining.

Top

Page created: July 13, 2010
Page updated: July 13, 2010
Page reviewed: July 13, 2010
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.
file_external