Changing patterns of chikunya virus: Re-emergence of a zoonotic arbovirus

Abstract:

CHIKV has been responsible for significant human morbidity for (probably) several hundred years; yet in spite of its prevalence, CHIKV epidemiology and mechanisms of virulence and pathogenesis are poorly understood. The 2005-2007 epidemic of CHIKV disease, like the West Nile virus (WNV) epidemics in North America that began in 1999, has served as a reminder that laboratory and field research combined with epidemiological preparedness are essential for timely and appropriate public health response and control measures. Curiously, it was the sheer magnitude of the 2005-2007 CHIKV outbreaks that brought this virus into the awareness of both the scientific community and the general public. The public has been introduced to the virus through numerous (and not always accurate) anecdotal and media reports of widespread death and devastation due to the virus. The outbreaks have even inspired the writing of songs about the virus and the recognition of 'Keelamma - the chikungunya goddess'. Unfortunately, much of the information published or reported about CHIKV includes only suspected cases and 'positive cases' that have not been laboratory confirmed, which has led to artificial epidemiological data. Scientifically, the large scope of the outbreaks has provided opportunities to accurately document transmission and epidemiological patterns associated with movement of the virus. Furthermore, because of the magnitude of the outbreak, 'unusual' patterns of illness and routes of transmission (similar to what was seen during the North American WNV epidemics) have been identified, leading to a resurgence of public health response capacity combined with an interest in expanding basic and applied scientific knowledge of the virus. Several potential research areas have been of particular focus including vector capacity, viral evolution and virulence potential. For example, CHIKV replicates in a number of mosquito vectors that are also common in the USA, Europe and South America and the virus could replicate to sufficient levels in humans to initiate localized transmission cycles leading to European epidemics during the summer months or establishment of the virus in the southern United States, the Caribbean or Latin America. Concomitant with the possibility of expansion into new ecological niches is the recognition that different mosquito populations may greatly affect the potential establishment and transmission of the virus; further vector competence studies of mosquitoes in areas where the virus is not enzootic but may be introduced by viraemic travellers are warranted to assess future risk to naïve populations. Whether or not the virus moves to the New World, it is still a significant burden on the already overstretched hospitals, health systems and communities of the affected regions where attack rates reach as high as 70% (Halstead et al., 1969d; Padbidri & Gnaneswar, 1979; Jupp & McIntosh, 1988). The economic pressures due to CHIKV infections are noted in the state and national laboratories, local businesses affected by absenteeism due to the incapacitating symptoms, and on individual families whose members are unable to work for weeks or months. Therefore, laboratory research aimed at the development of vaccine candidates, antiviral strategies and commercially available diagnostic kits is needed. To reach these goals, several investigations into further characterizing CHIKV are already ongoing including murine studies investigating cell tropism and neurovirulence determinants, transmissibility studies in mosquitoes using chimeric viruses, and virulence/pathogenesis studies investigating the outcomes due to CHIKV strain variation (A. M. Powers, C. H. Logue, J. P. Ledermann, B. J. Sheahan & G. J. Atkins, unpublished results). Hopefully, these efforts will lead to advances in public health capacity for prevention of future arboviral outbreaks combined with rapid control of outbreaks that do occur.

Año de publicación:

2007

Keywords:

Fuente:

scopus