Severe Perkinsea infection of frog tadpoles
Severe Perkinsea infection (SPI) is an emerging disease of frogs and is the third most common infectious disease of frogs after chytridiomycosis (infection with chytrid fungus) and ranavirus. It was first detected in 1999 in New Hampshire with detections in several other states in subsequent years. It was first identified in Wisconsin as the cause of green frog tadpole mortality in Vilas County in the summer of 2017.
SPI is caused by a protozoan (single-celled) parasite in the phylum Perkinsea that infects and causes mass mortalities in tadpoles. So far it has not been associated with the mortality of adult frogs. Outbreaks can cause tadpole mortality rates as high as 95% and can reoccur at the same location for multiple years.
TRANSMISSION
The protozoan parasites produce spores that persist in harsh conditions and remain viable even when wet areas dry up. Once a tadpole is infected the organism spreads throughout the body causing damage to multiple internal organs.
CLINICAL SIGNS
Infected tadpoles in Wisconsin were lethargic and observed swimming in circles and upside down. Other reported signs include enlargement of the body cavity and skin lesions/discoloration.
DISEASE MANAGEMENT
Currently little is known about the transmission of this parasite. When sick or dead amphibians (tadpoles, salamanders, frogs) are observed, care should be taken to prevent potentially moving any infectious diseases to another location. At a minimum, rinse off footwear and either air dry in the sun for a few days, disinfect with a 10% bleach solution or wipe off with 70% alcohol wipes before wearing to another water area.
PUBLIC HEALTH
There is no known risk to people or pets.