Chikungunya Fever, Mauritius, 2006

To the Editor: When an outbreak of chikungunya fever swept across several Indian Ocean islands in 2005 and 2006, the international public health community's attention was drawn to chikungunya virus (ge-nus Alphavirus, family Togaviridae). Among those areas affected was the Republic of Mauritius, located ≈900 km east of Madagascar, which has an estimated population of 1,250,000 and comprises the main island of Mauritius (area ≈1,865 km 2) and several outlying islands including Rodrigues (≈180 km 2). Mauritius Island had an initial outbreak of ≈3,500 suspected cases of chikungunya fever from April through June 2005 (1). With the onset of the drier season of winter, transmission of the virus subsided, but increased again during 2006. An outbreak began on Rodrigues Island in February 2006. The intensity of chikungunya fever outbreaks on Mauritius and Rodrigues Islands led us to explore the extent to which these outbreaks might have contributed to overall death rates. Chikungunya virus is transmitted to humans primarily by the bite of infected Aedes spp. mosquitoes. Aedes aegypti was effectively eliminated from the island of Mauritius during a malaria control campaign from 1949 through 1951 (2). However, A. al-bopictus is widely distributed on the island in rural and urban habitats (3); thus, A. albopictus may be the most likely vector for chikungunya virus. Common peridomestic breeding places in Mauritius include small pots and vases (used to decorate the outside of homes) and discarded rubber tires (3). Chikungunya fever was fi rst recognized in 1952 after an outbreak on the Makonde Plateau of Tanganyika Territory (4), currently part of Tan-zania. The word chikungunya is from a local dialect that translates to " that which bends up " in reference to the stooped posture often seen in patients with severe arthralgia (5). Human infections with chikungunya virus are associated with sudden onset of symptoms including headache, fever, rash, and muscle and joint pain (5). Before the outbreak in the Indian Ocean islands , deaths had not been associated with infections. However, Réunion Island reported >200 deaths during the 2006 chikungunya epidemic (January–April 2006) (6), and India conservatively estimated 1,194 deaths since the virus reemerged in Decem-ber 2005. (7). To determine whether a similar situation occurred in Mau-ritius, we compared expected number of deaths with observed number of deaths and estimated number of chi-kungunya cases from January through December 2006. Crude death rates (CDRs) and number of deaths were obtained from the Annual …