Factors influencing the re-emergence of plague in Madagascar.

Jennifer Alderson,Max Quastel,Emily Wilson,Duncan Bellamy,Jenny Low

doi:10.1042/etls20200334

Jennifer Alderson, Max Quastel + Show 3 more

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https://doi.org/10.1042/etls20200334

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Abstract

Plague is an infectious disease found worldwide and has been responsible for pandemics throughout history. Yersinia pestis, the causative bacterium, survives in rodent hosts with flea vectors that also transmit it to humans. It has been endemic in Madagascar for a century but the 1990s saw major outbreaks and in 2006 the WHO described the plague as re-emerging in Madagascar and the world. This review highlights the variety of factors leading to plague re-emergence in Madagascar, including climate events, insecticide resistance, and host and human behaviour. It also addresses areas of concern for future epidemics and ways to mitigate these. Pinpointing and addressing current and future drivers of plague re-emergence in Madagascar will be essential to controlling future outbreaks both in Madagascar and worldwide.

Highlights

Plague is a zoonotic disease caused by Yersinia pestis, a bacterium that usually survives in a rodent host and flea vector
Plague has been reduced by improved living conditions and indoor residual spraying of insecticides to kill flea vectors
This review suggests many steps to minimise the risk of future large-scale plague epidemics: minimisation of contact between humans and rodent hosts of Y. pestis, use of social distancing and masks to control pneumonic outbreaks, and development and distribution of a safe and effective vaccine

Summary

Introduction

Plague is a zoonotic disease caused by Yersinia pestis, a bacterium that usually survives in a rodent host and flea vector. The plague has affected humans for millennia, causing three major pandemics in the last 2000 years involving 200 million deaths [4], and has been endemic in the Madagascan highlands above 800 m altitude since the 1920s, showing a seasonal pattern of outbreaks [5–7] Factors governing these outbreaks are complex, involving changes in rodent populations, flea populations and the interactions of these with humans as well as the bacterium itself. This review will explore factors implicated in plague re-emergence in Madagascar, including changes in the environment, weather and climate, changes in host and vector species, socioeconomic changes, resistance of vector species against insecticides, and resistance of hosts against disease It will address antibiotic resistance in Y. pestis.

Enzootic cycle

Discussion

Summary