A brief discussion outlining the connection between environmental conditions and the spread of zoonotic disease
Left: Zoonotic Diseases (Photo: Centers for Disease Control and Prevention)
Zoonotic diseases, which are defined as those transferred between humans and animals, commonly appear with the help of vectors. Vectors, which operate as a mode of transportation for the pathogen to
navigate from human to animal, spread
vector-borne diseases and include frequent examples such as malaria and others such as yellow fever ("Vector-borne Diseases"). Spread by parasites, bacteria and viruses, these vector-borne diseases sometimes come in the form of outbreaks, targeting populations in sub-tropical areas most frequently. Their distribution, however, is not solely due to location or mobility; zoonotic diseases have many factors that play into their distribution such as environmental, demographic and social factors ("Vector-borne Diseases"). Of these environmental components, climate change has recently caused area for concern, since it impacts natural habitats and the behavior of populations as well.
Climate change is a multi-faceted issue and although it is influenced by many factors, the excessive use of fossil fuels and emission of carbon dioxide cause the greenhouse effect to exacerbate the intensity of which the impacts are felt (El-Sayed et. al). These conditions will lead to the increased temperatures, rainfall and in some places increased droughts and extreme weather. As weather conditions change and humidity levels increase, the environments suitable for the vector hosts change and may become more desirable for certain species (El-Sayed et. al). These hosts, which can range from insects to rodents to birds, will change their behaviors in response to their changing habitats and these behaviors will increase the transmission of zoonotic diseases to other animals and humans. For example, Chlamydia, which is a zoonotic bacteria carried by birds, will have altered transmission patterns as birds are forced to migrate to new areas more frequently as the environment faces the impacts of climate change (El-Sayed et. al).
This consistent spread of zoonotic disease is not only due to the migration of animals though. With construction of new cities and increased pollution rates, movement of populations from dry, depleted areas to new geographical locations will alter the epidemiological relationship between humans, animals and the environment ("Climate Change and Veterinary Medicine"). Although the Global Vector Control Response was initiated in 2017 and details on how to assist countries in strengthening vector control and prevent outbreaks were released, veterinarians play an important role in this process as well ("Vector-Born Diseases"). By conducting research, educating clients and using evidence-based guidance and technology to address such issues, veterinarians can educate clients on the impacts of zoonotic diseases.
“Climate Change and Veterinary Medicine.” The College of Veterinary Medicine at Michigan State University, cvm.msu.edu/vetschool-tails/climate-change-and-veterinary-medicine.
El-Sayed, Amr, and Mohamed Kamel. “Climatic Changes and Their Role in Emergence and Re-Emergence of Diseases.” Environmental Science and Pollution Research, vol. 27, no. 18, 2020, pp. 22336–22352., doi:10.1007/s11356-020-08896-w.
“Vector-Borne Diseases.” World Health Organization, World Health Organization, www.who.int/news-room/fact-sheets/detail/vector-borne-diseases.
“Zoonotic Diseases.” One Health: Zoonotic Disease, 2017, www.cdc.gov/onehealth/images/zoonotic-diseases-spread-between-animals-and-people.jpg.