The pandemic has generated a greater need for mental health services in a context where previously there was already a gap in access to services, so it is urgent to address this gap and promote the expansion of mental health services at the first level of care.
The impact of climate change on emerging viral diseases
Beyond the COVID-19 pandemic, the world remains at great risk for the emergence and re-emergence of epidemic and pandemic-prone pathogens. This threat arises from both imported cases and zoonotic spillover from autochthonous sources. The driving forces behind the spread and emergence of these pathogens are multifaceted, encompassing climate change, unplanned urbanization, encroachment of human settlements in sylvatic areas, indiscriminate use of land and water, increased global travel, in addition to socioeconomic factors, playing a significant role in the dynamic of infectious diseases and the way they spread.
Climate change impacts pathogen emergence by altering habitats and weather patterns. This leads to animals migrating closer to human settlements, heightening zoonotic transmission risks. Additionally, climate change significantly affects vector-borne diseases by influencing the life cycles and incubation periods of insect vectors, thereby altering disease transmission dynamics.
On the other hand, probably the most obvious impact of environmental and climate change occurs in vector-borne diseases. The life cycle of insect vectors is directly affected by climate and weather; temperature will influence the incubation period of the pathogens, and then also impacts the transmission patterns.
In recent years, the Americas has faced arthropod borne viruses (arboviruses) like dengue (DENV), chikungunya (CHIKV), Zika (ZIKV) in urban areas, alongside with others in sylvatic settings such as yellow fever (YFV), West Nile Virus (WNV), Mayaro (MAYV), and equine encephalitis Virus (EEV), spreading to new areas previously unaffected, due to climate change (among other environmental and socio-economic factors), leading the adaptation and geographic expansion of the mosquito vectors. In the Americas, with more than 3,508,000 cases of DENV only in 2023, more than 3,800,000 CHIKV cases between 2014 and 2023, and around 1,000,000 ZIKV cases (besides the devastating effects of congenital malformations and neurological impact), it is clear how these viruses have imposed an increasing burden to Public Health Systems, generating both human and economic loss.
Undoubtedly, climate change and its impact on the environment are playing an important role in the way several viral diseases are increasing the risk of outbreaks and epidemics. Given this situation, enhancing surveillance capabilities to monitor existing viral diseases and detect new pathogens promptly is critical, particularly in those areas where the impact of weather might be critical. However, this will not be sufficient if we do not raise awareness about the effects of climate change and human behavior on the dynamics of infectious pathogens, along with promoting changes in habits and practices to mitigate these impacts, which is equally vital.
The Infectious Hazards Management Unit (IHM), from the Health Emergency Department, has been working to strengthen surveillance capacities for early detection and diagnosis of emerging and epidemic prone viral diseases, integrating epidemiology, virology, and laboratory, genomics, and clinical management. Also, IHM supports forecasting and risk characterization of infection and disease risks (including in potential animal and wildlife reservoirs), and the development of evidence-based strategies to predict, prevent, detect, and respond to those infectious hazards. Finally, working in a transversal way, involving other departments and units (Communicable Diseases Prevention, Control and Elimination-CDE, Social and Environmental Determinants for Health Equity, DHE, among others) has been critical to better support the Member States. Finally, implementing the One-Health approach to cover all the components that affect human, animal, and environmental well-being is a PAHO priority.
More information:
Strategy for arboviral disease prevention and control. 55th Directing Council. 68th Session of the Regional Committee of WHO for the Americas (2016).
Additional References
1. Ogden, N. Climate change and vector-borne diseases of public health significance. FEMS Microbiology Letters, 364, 2017, doi: 10.1093/femsle/fnx186 https://pubmed.ncbi.nlm.nih.gov/28957457/
2. Robert, MA., Stewart-Ibarra, AM., Estallo, EL. Climate change and viral emergence: evidence from Aedes-borne arboviruses. Curr Opin Virol. Feb:40:41-47. 2020, doi: 10.1016/j.coviro.2020.05.001. https://pubmed.ncbi.nlm.nih.gov/32569752/
3. Stewart Ibarra, AM., Ryan, SJ., Beltran, E., Mejia, R., Silva, M., Munoz, A. Dengue Vector Dynamics (Aedes aegypti) Influenced by Climate and Social Factors in Ecuador: Implications for Targeted Control. PLoS ONE 8(11): e78263. 2013, doi:10.1371/journal.pone.0078263 https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0078263&type=printable
4. Chan, M., Johansson, MA. The Incubation Periods of Dengue Viruses. PLoS ONE 7(11): e50972. 2012, doi:10.1371/journal.pone.0050972 https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0050972&type=printable
5. Gortazar, Ch. Reperant, LA. Kuiken, T. de la Fuente, J. Boadella, M. Martıinez-Lopez, B. et al. Crossing the Interspecies Barrier: Opening the Door to Zoonotic Pathogens. PLoS Pathogens · April 2014doi: 10.1371/journal.ppat.1004129 https://www.researchgate.net/publication/261288678_Crossing_the_Interspecies_Barrier_Opening_the_Door_to_Zoonotic_Pathogens/link/0046353a433d5f232e000000/download
6. Johansson, MA., Arana-Vizcarrondo, N., Biggerstaff, BJ., Staples, E. Incubation Periods of Yellow Fever Virus. Am. J. Trop. Med. Hyg., 83(1), 2010, doi:10.4269/ajtmh.2010.09-0782 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2912597/pdf/tropmed-83-183.pdf
7. Clegg, JC. Influence of climate change on the incidence and impact of arenavirus diseases: a speculative assessment. Clinical Microbiology and Infection, 15, Issue 6, June 2009, doi.org/10.1111/j.1469-0691.2009.02847.x https://www.sciencedirect.com/science/article/pii/S1198743X14604377#bib16