The west nile virus outbreak in Israel (2000) from a new perspective: The regional impact of climate change

Abstract

The West Nile Virus (WNV) outbreak in Israel in 2000 appeared after medical and climatic warning signs. Re-analysis of the epidemic from a new viewpoint, the regional impact of global warming, especially the worsening in the summers' heat conditions, is presented. The disease appeared averagely at a lag of 3–9 weeks (strongest correlation = lag of 7 weeks). The minimum temperature was found as the most important climatic factor that encourages the disease earlier appearance. Extreme heat is more significant than high air humidity for increasing WNV cases. An early extreme rise in the summer temperature could be a good indicator of increased vector populations. While 93.5% of cases were in the metropolitan areas, the disease was not reported in the sub-arid regions. The outbreak development was comparable to the cases from Romania (1996) and NYC (1999). Each of those epidemics appeared after a long heatwave.

Keywords:

• West Nile Virus
• regional climate changes
• extreme heat
• Israel

Acknowledgements

The author would like to thank Prof. N. Kliot and Prof. H. Kutiel for their constructive comments and remarks. Thanks are also due to Dr. D. Gandacu from the Department of Epidemiology, Israeli Ministry of Health, for his kind help with the WNV database.