(Other names: amphibian perkinsea, perkinsea)
Description
Severe perkinsea infection (SPI) is an emerging infectious disease that causes die-offs of tadpoles. Perkinsea are parasitic protozoans, single-celled eukaryotes that are known to infect marine mussels and freshwater fish. The discovery of a new group of perkinsea infecting amphibian tadpoles adds to the diversity of perkinsea hosts. In the body of the tadpole, perkinsea multiplies, primarily affecting the liver, and causing organ failure. SPI can have high mortality rates, about 95%, for tadpoles that become infected, which can contribute to amphibian population declines. Amphibians are declining globally, and synergistic pressure such as habitat destruction and disease are responsible for the decline of many species.
The first case of perkinsea was documented in 1999 in New Hampshire. The disease has since been detected in at least 10 states, Panama, and the United Kingdom. Perkinsea has caused mortality events in tadpoles of threatened species in the southern United States. In Indiana, a die-off of crawfish frog tadpoles, a state endangered species, was recently linked to SPI. Perkinsea has not been documented to infect adult frogs.
Transmission
SPI has gained more scientific attention within the past decade. Tadpoles can become infected by ingesting perkinsea or the parasite contacting the skin or gills. Tadpoles are commonly found at high densities, which allows the disease to rapidly spread through the population. Perkinsea spores can survive drying out and can become infectious when returning to the water.
Clinical Signs
SPI progresses quickly in tadpoles. Infected tadpoles are often visibly bloated, may be red in coloration due to hemorrhaging, have an enlarged liver, and can experience difficulty in swimming.
Wildlife Management Implications
A few species in Indiana are known to be susceptible to SPI from outbreaks in other states in recent years. The detection of SPI causing a die-off of crawfish frogs in Indiana was the first time the disease has been detected in the state. Preventing the spread of perkinsea is important; however, perkinsea spores are not easily destroyed as they are known to be resistant to some common disinfectants (bleach) and can survive drying out. If traveling between wetlands or areas with amphibians, it is important to thoroughly clear mud and debris from boots, clothing, and equipment to prevent the spread of perkinsea and other diseases. Avoid collecting and transporting amphibians between areas. If you observe tadpoles behaving abnormally or that are sick or dying, please submit a report using this link: Sick or Dead Wild Animal Report.
Human Health Significance
Perkinsea is not known to impact human health.
Additional Resources
- Cornell College of Veterinary Medicine Fact Sheet
- University of Pennsylvania PennVet Fact Sheet
- Atkinson, M. S., & Savage, A. E. (2023). Widespread amphibian Perkinsea infections associated with Ranidae hosts, cooler months and Ranavirus co-infection. Journal of Animal Ecology, 92(9), 1856–1868. https://doi.org/10.1111/1365-2656.13977
- Isidoro-Ayza, M., Grear, D. A., & Chambouvet, A. (2019). Pathology and Case Definition of Severe Perkinsea Infection of Frogs. Veterinary Pathology, 56(1), 133–142. https://doi.org/10.1177/0300985818798132
- Isidoro-Ayza, M., Lorch, J. M., Grear, D. A., Winzeler, M., Calhoun, D. L., & Barichivich, W. J. (2017). Pathogenic lineage of Perkinsea associated with mass mortality of frogs across the United States. Scientific Reports, 7(1), 10288. https://doi.org/10.1038/s41598-017-10456-1
- Smilansky, V., & Richards, T. A. (2023). Amphibian Perkinsea. Current Biology, 33(1), R8–R10.