Natural Disasters and the Risk of Increasing the Spread of Zoonotic
Madeline Shani ’25
Cathy Zhang ’26
Zoonotic diseases are infections transmitted from animals to humans. They occur in the form of bacteria, viruses, parasites, and fungi. Some of the most prominent zoonotic diseases include rabies, lyme disease, malaria, leptospirosis, and influenza. All of these pose a threat to society and human health. Unfortunately, natural disasters have an additional effect on the frequency of these diseases. Natural disasters on their own have the ability to cause extreme destruction to different communities, families and countries all around the world. The risk of increase of zoonotic diseases in the case of natural disasters can make matters even more harmful to human life. Zoonotic diseases can spread in various ways, and their transmission can be further exacerbated by natural disasters. The correlation between natural disasters and zoonotic diseases is not inherently direct, but over the past few decades, numerous studies have analyzed how these two phenomena interact.
One way natural disasters affect zoonotic diseases is through the displacement of animals. When disasters such as floods, wildfires, and earthquakes occur, they often lead to displacement and forced migration. One study was conducted in Sindh, Pakistan, by Dorien H. Braam, focusing on floods that took place in 2010. In Sindh, many lives depend on livestock. In such circumstances, natural disasters significantly heighten the risk of zoonotic diseases due to both animal and human displacement. When disasters strike, people are forced to flee their homes. During the 2010 floods, many had to leave their homes and reason what to do with their livestock. As a result, many families were separated. Some members of the families would move into shelters while others remained in informal settlements with their livestock. These living conditions in close proximity to animals led to an increased risk of zoonotic diseases. The study found that the impact of these diseases was compounded by social and economic disparities in this situation. As the disaster impacted a vulnerable population, families in these circumstances were faced with limited access to healthcare or veterinary support, and therefore faced a higher risk of infection.
Another study on zoonotic diseases by S. Karande focused on torrential rains and floods that occurred in Mumbai, India, in the year 2000. Leptospirosis is a disease spread through the urine of infected animals and therefore the flooding created ideal conditions for this disease to spread. In consequence to this finding, researchers used antibody testing to test children who had come in contact with the floodwater for Leptospirosis. Of those tested, 35% came back positive. This provided evidence that the spread of floodwater contributed to the further transmission of the disease.
References:
Braam, D. H., Chandio, R., Jephcott, F. L., Tasker, A., & Wood, J. L. N. (Year). Disaster displacement and zoonotic disease dynamics in Sindh, Pakistan.
Karande, S., Bhatt, M., Kelkar, A., Kulkarni, M., De, A., & Varaiya, A. (2003). An observational study to detect leptospirosis in Mumbai, India, 2000. Archives of Disease in Childhood, 88(12), 1070-1075. https://doi.org/[DOI
