Reviewing estimates of the basic reproduction number for dengue, Zika and chikungunya across global climate zones

Ying Liu; Kate Lillepold; Jan C Semenza; Yesim Tozan; Mikkel B M Quam; Joacim Rocklöv

doi:10.1016/j.envres.2020.109114

Reviewing estimates of the basic reproduction number for dengue, Zika and chikungunya across global climate zones

Environ Res. 2020 Mar:182:109114. doi: 10.1016/j.envres.2020.109114. Epub 2020 Jan 3.

Authors

Ying Liu¹, Kate Lillepold², Jan C Semenza², Yesim Tozan³, Mikkel B M Quam⁴, Joacim Rocklöv⁵

Affiliations

¹ School of International Business, Xiamen University Tan Kah Kee College, Zhangzhou, 363105, China. Electronic address: yingliu722@163.com.
² European Centre for Disease Prevention and Control, Stockholm, Sweden.
³ New York University, College of Global Public Health, New York, NY, USA. Electronic address: tozan@nyu.edu.
⁴ Department of Public Health and Clinical Medicine, Section of Sustainable Health, Umeå University, Umeå, Sweden.
⁵ Department of Public Health and Clinical Medicine, Section of Sustainable Health, Umeå University, Umeå, Sweden. Electronic address: joacim.rocklov@umu.se.

PMID: 31927301
DOI: 10.1016/j.envres.2020.109114

Abstract

Background: Globally, dengue, Zika virus, and chikungunya are important viral mosquito-borne diseases that infect millions of people annually. Their geographic range includes not only tropical areas but also sub-tropical and temperate zones such as Japan and Italy. The relative severity of these arboviral disease outbreaks can vary depending on the setting. In this study we explore variation in the epidemiologic potential of outbreaks amongst these climatic zones and arboviruses in order to elucidate potential reasons behind such differences.

Methodology: We reviewed the peer-reviewed literature (PubMed) to obtain basic reproduction number (R₀) estimates for dengue, Zika virus, and chikungunya from tropical, sub-tropical and temperate regions. We also computed R₀ estimates for temperate and sub-tropical climate zones, based on the outbreak curves in the initial outbreak phase. Lastly we compared these estimates across climate zones, defined by latitude.

Results: Of 2115 studies, we reviewed the full text of 128 studies and included 65 studies in our analysis. Our results suggest that the R₀ of an arboviral outbreak depends on climate zone, with lower R₀ estimates, on average, in temperate zones (R₀ = 2.03) compared to tropical (R₀ = 3.44) and sub-tropical zones (R₀ = 10.29). The variation in R₀ was considerable, ranging from 0.16 to 65. The largest R₀ was for dengue (65) and was estimated by the Ross-Macdonald model in the tropical zone, whereas the smallest R₀ (0.16) was for Zika virus and was estimated statistically from an outbreak curve in the sub-tropical zone.

Conclusions: The results indicate climate zone to be an important determinant of the basic reproduction number, R₀, for dengue, Zika virus, and chikungunya. The role of other factors as determinants of R₀, such as methods, environmental and social conditions, and disease control, should be further investigated. The results suggest that R₀ may increase in temperate regions in response to global warming, and highlight the increasing need for strengthening preparedness and control activities.

Keywords: Aedes aegypti; Aedes albopictus; Arbovirus; Basic reproduction number; Chikungunya; Climate; Dengue; R(0); Zika virus.

Publication types

Research Support, Non-U.S. Gov't
Review

MeSH terms

Aedes*
Animals
Basic Reproduction Number
Chikungunya Fever*
Climate*
Dengue*
Italy
Japan
Zika Virus Infection*
Zika Virus*