Introduction:Barmah Forest virus (BFV) is a mosquito-borne virus causing epidemic polyarthritis in Australia. This study used case follow-up of cases from the surveillance system to demonstrate that routinely collected BFV notification data were an unreliable indicator of the true location of exposure.Methods:BFV notifications from June 2001 to May 2011 were extracted from the New South Wales (NSW) Notifiable Conditions Information Management System to study case distribution. Disease cluster analysis was performed using spatial scan statistics. Exposure history data were collected from cases notified in 2010 and 2011 to accurately determine travel to high-risk areas.Results:Cluster analysis using address data identified an area of increased BFV disease incidence in the mid-north coast of NSW contiguous with estuarine wetlands. When travel to this area was investigated, 96.7% (29/30) cases reported having visited coastal regions within four weeks of developing symptoms.Discussion:Along the central NSW coastline, extensive wetlands occur in close proximity to populated areas. These wetlands provide ideal breeding habitats for a range of mosquito species implicated in the transmission of BFV. This is the first study to fully assess case exposure with findings suggesting that sporadic cases of BFV in people living further away from the coast do not reflect alternative exposure sites but are likely to result from travel to coastal regions. Spatial analysis by case address alone may lead to inaccurate understandings of the true distribution of arboviral diseases. Subsequently, this information has important implications for the collection of mosquito-borne disease surveillance information and public health response strategies.

The world is facing serious health and economic threats from the global coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The burden of disease has been significant, with tens of millions of cases and more than 1.5 million deaths reported globally.1 Since its emergence in Wuhan, China, in late 2019, COVID-19 has spread around the world, affecting almost all countries. COVID-19 is a highly contagious disease that is spread by direct contact and respiratory droplets, and patients can be infective while presymptomatic or asymptomatic.2 To reduce opportunities for transmission, most developed countries have implemented lockdowns, causing significant social and economic disruption. Mosquito-borne diseases, such as malaria and dengue, are a substantial burden in many countries, especially those with developing economies. Malaria is the most significant mosquito-borne disease, with about 228 million cases reported in 2018 and 231 million in 2017, and 405 000 deaths in 2018 and 416 000 in 2017.3 Dengue is the most commonly reported arboviral disease internationally, with Asia suffering a significant disease burden.4 In countries facing endemic and epidemic malaria and dengue, disruption to government services (in health and non-health sectors) and to public health services could severely impact the ability to implement strategic responses to mosquito-borne diseases. As of 30 June 2020, all malaria-endemic countries in Asia had confirmed cases of COVID-19, and those with developing economies face a particularly serious threat to malaria control efforts. In these countries, local authorities responsible for malaria and dengue control must make strategic preparations for continuing with control measures, both during and after the COVID-19 pandemic.