Recognizing the growing impact of climate change on infectious diseases

Mechanisms of Climate Change-Induced Disease Spread

Climate change boosts disease spread by accelerating vector development, expanding their range, and creating more breeding sites through increased rainfall and flooding. Higher temperatures and extreme weather events also enhance vector proliferation and disrupt sanitation.

Temperature and Pathogen Growth

Temperature plays a crucial role in the life cycles of many pathogens and their vectors. Changes in temperature and humidity levels, driven by global climate change, affect the emergence and spread of infectious diseases.

Rising temperatures and unprecedented flooding have facilitated the spread of mosquitoes far beyond their traditional breeding grounds, introducing Lyme disease, dengue fever, malaria, and the Zika virus to previously unaffected regions.

Humidity and Vector Proliferation

Much like temperature, humidity also impacts the proliferation of disease vectors. For example, increased rainfall and higher humidity levels create favorable conditions for breeding mosquitoes and other vectors, thereby facilitating the spread of vector-borne diseases.

Additionally, regions experiencing increased precipitation and flooding will likely see a rise in water-borne diseases like cholera and leptospirosis. Existing literature indicates that floods increase cholera, cryptosporidiosis, non-specific diarrhea, rotavirus, typhoid, and paratyphoid fever cases.

For example, a cross-sectional survey of 7,814 flood victims in Pakistan found that 30% suffered from digestive system infections, 33% experienced skin and soft tissue infections, 7% had conjunctivitis, 5% had respiratory tract infections, and 4% were likely affected by malaria.

Climate-Linked Disease Outbreaks

Climate change increases the risk of vector-borne diseases like Lyme disease, West Nile virus, malaria, dengue fever, and Zika by accelerating mosquito development, expanding their habitats, and altering migration patterns. Warmer temperatures and shifting rainfall patterns enhance transmission and broaden the geographical reach of these diseases.

Lyme Disease

Research indicates that climate change has led to an expansion in the range of ticks, thereby increasing the potential risk of Lyme disease in North American regions, where ticks previously could not survive. The life cycle and prevalence of deer ticks are closely linked to temperature. For instance, deer ticks are primarily active when temperatures exceed 45˚F and flourish in environments with at least 85% humidity. Consequently, rising temperatures due to climate change are expected to expand the habitat suitable for ticks, contributing to the spread of Lyme disease.

Additionally, milder winters may prolong the period during which ticks are active each year, thereby increasing human exposure to Lyme disease. Unlike some vector-borne diseases, tick-borne disease patterns are more influenced by long-term climate change than short-term weather fluctuations.

West Nile Virus

Climate change heightens the risk of human exposure to the West Nile virus (WNV). Research indicates that rising temperatures linked to climate change can speed up mosquito development, increase biting rates, and accelerate the virus's incubation period within mosquitoes — especially the Culex species that carry the virus. Additionally, shifts in climate can affect the timing of bird migration and breeding patterns, potentially influencing the long-distance spread of the virus. Mild winters and drought conditions have also been connected to outbreaks of WNV.

These factors can lead to more frequent outbreaks and expand WNV into new regions. In the United States, the CDC notes that the incidence of WNV has been closely linked to unusually warm winters and hot, dry summers.

Malaria

Malaria, caused by Plasmodium parasites and transmitted by Anopheles mosquitoes, is another infectious disease impacted by climate change. As noted in the 2023 World Malaria Report, the Intergovernmental Panel on Climate Change projects that, even with moderate greenhouse gas emissions scenarios, an additional 51 to 62 million people could be at risk of malaria by the 2030s. Warmer temperatures and increased rainfall can expand the habitats of malaria-carrying mosquitoes, leading to higher transmission rates in previously low-risk areas.

For instance, the 2022 catastrophic flooding of Pakistan resulted in a five-fold surge in malaria cases across the country.

Dengue Fever

Dengue fever, transmitted by Aedes mosquitoes, is currently limited to tropical and subtropical regions. However, climate models predict that global warming will expand the range of these mosquitoes to temperate regions, increasing the risk of dengue outbreaks in new areas​.

In Brazil, dengue is already spreading geographically. Brazil’s Ministry of Health reveals that the country exceeded 5 million dengue fever cases in 2024, setting a new record that surpasses even the government's most pessimistic predictions. Scientists link this rapid expansion of dengue to factors such as climate change, urbanization, increased human mobility, and a larger portion of the country becoming suitable for mosquito vectors.

However, cases are even increasing in areas outside the tropical and subtropical zones. In France, for example, no locally transmitted cases of dengue had been documented prior to 2010, but 36 cases were reported in 2023. This is partly due to the expanded range of A. albopictus, now found in two-thirds of the country.

Without intervention, experts estimate that dengue fever could impact 60% of the world’s population by 2080.

Zika

Climate change worsens Zika virus infections by creating favorable conditions for Aedes mosquitoes, leading to larger populations and expanded geographical ranges. Extreme weather events and altered rainfall patterns also increase mosquito breeding sites and impact human behavior, further promoting the spread of the virus.

Researchers from the University of Michigan School of Public Health project that the transmission potential of Zika or dengue in Brazil could rise by 10–20% over the next 30 years due to warming temperatures associated with climate change.

Without intervention, Zika could threaten an additional 1.3 billion people by 2050.

The Role of Healthcare Technology

As climate change continues to alter the landscape of infectious diseases, the healthcare industry must adapt to these new challenges. Innovative solutions are needed to improve disease surveillance, enhance diagnostic tools, and develop effective treatment protocols.

Enhanced Disease Surveillance

Modern healthcare technology can significantly enhance disease surveillance capabilities. Integrating big data analytics, artificial intelligence, and remote sensing technologies can provide real-time monitoring of disease outbreaks and predict future trends. This proactive approach can help healthcare providers and policymakers respond swiftly to emerging health threats. Predictive modeling using climate and environmental data has already been used to forecast disease outbreaks with remarkable accuracy​.

Advanced Diagnostic Tools

Improving diagnostic tools is critical for the early detection and management of infectious diseases. Point-of-care testing devices offer rapid and accurate diagnostics and are particularly valuable in remote and resource-limited settings. These devices can be crucial in identifying and containing outbreaks early. Partly due to the COVID-19 global pandemic, the development of portable PCR machines and smartphone-based diagnostics has revolutionized how infectious diseases are detected and monitored in real time​.

Telemedicine and Remote Care

Telemedicine platforms can help bridge the gap between healthcare providers and patients, especially in areas affected by climate-induced disruptions. These platforms enable remote consultations, continuous monitoring, and timely intervention, reducing the burden on healthcare facilities and improving patient outcomes. During the COVID-19 pandemic, telemedicine saw a 154% increase in use, demonstrating its potential in managing infectious diseases in various settings.

Anthropogenic climate change profoundly influences the epidemiology of infectious diseases by altering the environments in which disease vectors thrive. Rising temperatures, changing precipitation patterns, and extreme weather events create conditions that facilitate the spread of infectious diseases such as West Nile virus, malaria, dengue fever, and Zika. The expanding range of these diseases highlights the urgent need for advanced healthcare technologies to enhance disease surveillance, improve diagnostic tools, and develop effective treatment protocols. By integrating innovative solutions and adapting to these evolving challenges, the healthcare industry can better manage and mitigate the impact of climate change on global health.