Is climate change affecting parasite prevalence?

May 8, 2018
Katie James, dvm360 Associate Content Specialist
Katie James, dvm360 Associate Content Specialist

Katie James is an Associate Content Specialist for UBM Animal Care. She produces and edits content for and its associated print publications, dvm360 magazine, Vetted and Firstline. She has a passion for creating highly-engaging content through the use of new technology and storytelling platforms. In 2018, she was named a Folio: Rising Star Award Honoree, an award given to individuals who are making their mark and disrupting the status quo of magazine media, even in the early stages of their careers. She was also named an American Society of Business Publication Editors Young Leader Scholar in 2015. Katie grew up in the Kansas City area and graduated from the University of Kansas with a degree in journalism. Outside of the office her sidekick is an energetic Australian cattle dog mix named Blitz.

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The warming environment has already caused changes in Arctic ice. What does it mean for parasites? |

Talk about climate change has been ever-increasing over the last few years, and there's evidence of the consequences that it'll have on the weather and other natural phenomenon. But what about prevalence for disease-carrying parasites that affect pets and people? Fetch dvm360 speaker Richard Gerhold, DVM, MS, PhD, runs through a few parasites that could already be affected by these changes.

Dirofilaria immitis (heartworm)

A warming environment can lead to an increase in larval stage development in mosquitoes, potentially influencing the expansion of heartworm disease incidence. Other factors include an increase in mosquito populations in cooler months and certain mosquito species that are able to inhabit northern or higher-altitude regions that weren't previously occupied by vector-carrying species, Dr. Gerhold says. Another factor that's contributing to the spread of heartworm disease is urbanization. More areas of standing water, such as flower pots, old tires and buckets, provide space for mosquitoes to breed. Similar trends of increasing infection are expected for humans, domestic and wild animals, which has already been observed in certain northern states in the United States, Dr. Gerhold notes.


In the environment, sporulation of Toxoplasma gondii occurs between one to five days, and under favorable conditions sporocysts can survive about 18 months in fresh or salt water, Dr. Gerhold says. Sporulation can happen faster in warmer environments, leading to a more rapid production of oocysts in the environment.


Like Toxoplasma gondii, sporulation with coccidia happens in one to five days, and under favorable conditions, oocysts can survive for about 18 months. This sporulation can happen faster in warmer climates, leading to more oocysts in the environment. Higher oocyst production and ingestion leads to greater pathology because of parasite replication within the host cells, Dr. Gerhold says.

Ancylostoma species (hookworm)

The increase in air and soil temperatures will likely lead to increased numbers of infective L3 larva in the environment, Dr. Gerhold says. This has been seen with a higher incidence of human cutaneous larval migrans due to both canine and feline hookworm species during abnormally warm periods in various regions.

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