Impact of COVID-19 Mitigation Measures on Mosquito-Borne Diseases in 2020 in Queensland, Australia.

Cassie C Jansen,Andrew F Van Den Hurk,Jonathan M Darbro,Martin A Shivas,Frances A Birrell

doi:10.3390/v13061150

Abstract

We describe the impact of COVID-19 mitigation measures on mosquito-borne diseases in Queensland, Australia, during the first half of 2020. Implementation of restrictions coincided with an atypical late season outbreak of Ross River virus (RRV) characterized by a peak in notifications in April (1173) and May (955) which were greater than 3-fold the mean observed for the previous four years. We propose that limitations on human movement likely resulted in the majority of RRV infections being acquired at or near the place of residence, and that an increase in outdoor activities, such as gardening and bushwalking in the local household vicinity, increased risk of exposure to RRV-infected mosquitoes. In contrast, the precipitous decline in international passenger flights led to a reduction in the number of imported dengue and malaria cases of over 70% and 60%, respectively, compared with the previous five years. This substantial reduction in flights also reduced a risk pathway for importation of exotic mosquitoes, but the risk posed by importation via sea cargo was not affected. Overall, the emergence of COVID-19 has had a varied impact on mosquito-borne disease epidemiology in Queensland, but the need for mosquito surveillance and control, together with encouragement of personal protective measures, remains unchanged.

Highlights

The coronavirus infectious disease 19 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an unprecedented event that has significantly impacted the social, political and economic infrastructure of many countries [1]
We describe the status of mosquito-borne pathogens in the state of Queensland, Australia, in the first six months of 2020 when emergency measures were implemented to limit the impact of COVID-19
Of the 75 arboviruses that have been identified in Australia, Ross River virus (RRV) infections account for the largest number of human mosquito-borne disease notifications

Summary

Introduction

The coronavirus infectious disease 19 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an unprecedented event that has significantly impacted the social, political and economic infrastructure of many countries [1]. In response to the emergence of COVID-19 in Australia, numerous measures were implemented to prevent and suppress transmission including restricting entry by non-citizens and non-residents, mandatory quarantine for international travellers, self-isolation for diagnosed COVID-19 cases, limitation of movement outside residents’ homes and strict physical distancing requirements [4]. These measures had widespread and varied impact across education, employment, health, trade, tourism, sport and recreation, religious practice and regular social community practices and gatherings. We describe the status of mosquito-borne pathogens in the state of Queensland, Australia, in the first six months of 2020 when emergency measures were implemented to limit the impact of COVID-19

Unseasonal RRV Transmission

Importation of Exotic Pathogens by Overseas Travellers

Exotic and Invasive Mosquitoes

Impact on Workforce

Findings

Conclusions