On 4 October, healthcare practitioners and stakeholders gathered at IDWeek 2019 in Washington DC to discuss issues related to the influence of climate change on infectious diseases.
Representatives from the local and national level highlighted trends indicating that a vast portfolio of pathogens is affected by climate change, particularly vector-borne agents like Lyme disease. A key point of emphasis was the need for a long-term commitment from the medical community to improving disease surveillance, climate preparedness, and local capacity to avert catastrophic epidemics.
According to the 4th Annual Climate Assessment published in 2018, the current period is now the warmest in the history of modern civilization, and human activities are the dominant cause of observed climate deviations. Temperature and precipitation play significant roles in disease transmission by disturbing the replication, interaction, and propagation of infectious agents in disease vectors and the environment.
Key climate-sensitive infectious diseases comprise zoonotic, food-borne, and vector-borne diseases, including infections like West Nile and Eastern Equine Encephalitis which have recently spread to broader regions of the US. Speakers emphasised that the first frost of the season is a critical factor in ending mosquito seasons and epidemics, and therefore fewer days of frost directly contributes to the increased seasonal risk of infection.
In 2017, there were 66,867 cases of infections from mosquitos, ticks, and fleas compared to 30,501 in 2006. Most importantly, the harms of climate change are disproportionately felt in low income and vulnerable communities.
One session focused on issues facing the state of Alaska, which contains numerous distinct ecological regions experiencing unique climate challenges. In recent years, Alaska has been battered by storm surges due to loss of sea ice, periods of unprecedented dryness, and summer temperatures exceeding 90 degrees Fahrenheit for the first time in recorded history. The loss of permafrost and other weather-related damage to Alaska’s modern infrastructure has impacted running water systems, particularly in more rural regions of the state. Several studies have identified a direct relationship between the availability of running water in Alaska and the incidence of pneumonia, respiratory syncytial virus (RSV), and lower respiratory tract infections, particularly in children. Higher temperatures have also eroded permafrost-based food storage facilities, exposing inhabitants to greater risks of contaminated meat.
Even more directly, warming temperatures have facilitated the growth of microbiological organisms in previously inhospitable Alaskan regions. In 2004, Vibrio parahaemolyticus was identified for the first time in the Prince William Sound when several people fell ill after consuming raw oysters. It was found that temperatures in the water had drifted above 15 degrees Celsius for an extended period of time, which allowed uncharacteristic bacteria growth to facilitate the outbreak. Alaskan healthcare officials have advanced a one health initiative to combat the effects of climate change at the state, regional, and national levels, pushing to declare climate change a public health emergency.
According to survey data gathered from three medical societies, the majority of physicians believe climate change has direct relevance to patient care, with 70% believing it has already harmed individuals under their care. Data also indicates that the general public is less concerned about climate change than the medical community, but that their level of engagement increases once health concerns are raised.
Speakers at IDWeek concluded that proactive health actions on climate are the imperative of all healthcare practitioners. Key steps include engaging the health sector to call for action and incorporating climate solutions into public health systems to build resilient communities. The Infectious Disease Society of America (IDSA) has embraced this initiative by releasing a position statement on climate change and infectious diseases and moving to reduce its own environmental impact by eliminating paper waste and divesting from fossil fuel companies.
IDWeek is the joint annual meeting of the Infectious Diseases Society of America (IDSA), Society for Healthcare Epidemiology of America (SHEA), the HIV Medical Association (HIVMA), and the Pediatric Infectious Diseases Society (PIDS).
GlobalData (2019). Expert Insight: Rising CO2 Levels May Drive Increase in Disease-Carrying Mosquitos, November 2018, GDHC2107EI