Loading...
Chikungunya virus (CHIKV) has spread from Africa (Journal Watch Infectious Diseases Oct 18 2006), causing massive outbreaks in the Indian Ocean islands and India in recent years. The virus is transmitted by Aedes mosquitoes.
In 2007, CHIKV caused an outbreak of acute febrile illnesses in northeastern Italy. Investigators identified 205 cases occurring between July 4 and September 27 that met clinical and epidemiologic criteria for the condition; 175 of them were laboratory confirmed. Besides high fever, common symptoms included joint pain (97.1%), skin rash (51.7%), and headache (51.2%). The attack rate in the two villages was 5.4% and 2.5% but increased with age (1.6% for inhabitants <40 vs. 8.8% for those ≥80). One patient with underlying medical problems died. CHIKV was detected by PCR in local Aedes albopictus mosquitoes. Phylogenetic analysis showed that the outbreak virus resembled strains found in the Indian Ocean island outbreaks.
The index case was a visitor from India who became ill on June 23 while in Italy. Mapping of cases showed that the virus spread both contiguously and by jumping to other locations.
Rezza G et al. Infection with chikungunya virus in Italy: An outbreak in a temperate region. Lancet 2007 Dec 1; 370:1840.
Chretien JP and Linthicum KJ. Chikungunya in Europe: What’s next? Lancet 2007 Dec 1; 370:1805.
Comment
The authors and editorialists note factors that may have contributed to this outbreak, including preexisting heavy infestation of the region with A. albopictus and a chikungunya virus variant that is well adapted to this vector. A. albopictus, which was introduced into the U.S. via used tires from Asia in 1986 and has since spread to 28 states, now also inhabits Pacific Ocean islands, parts of Africa and Latin America, and 14 European countries. Of note, this mosquito vector was first documented in Italy in 1990, with the source identified as used tires imported from the U.S. Regions with competent vector populations in place can potentially support local transmission of viruses, such as CHIKV. Travel and trade continue to move vectors and viruses.