Prevalence and Pathology Associated with Sarcocystis spp. in Raptors in Tennessee, USA

Area of Science:

• Veterinary Parasitology
• Avian Pathology
• Wildlife Disease Ecology

Background:

• Raptors are known hosts for Sarcocystis species, acting as both intermediate and definitive hosts.
• Previous studies show varied outcomes, from fatal encephalitis to asymptomatic infections in raptors.
• Limited data exists on Sarcocystis prevalence in raptors within the eastern United States.

Purpose of the Study:

• To investigate the prevalence of Sarcocystis tissue cysts in raptors from eastern Tennessee.
• To identify histopathologic changes associated with Sarcocystis infections in these birds.
• To characterize Sarcocystis species infecting raptors in this region.

Main Methods:

• Histopathologic examination of tissues from 33 raptors in Tennessee.
• Identification of Sarcocystis spp. cysts in cardiac, skeletal, and tracheal muscles.
• Polymerase Chain Reaction (PCR) targeting the 18S rRNA gene for species identification.
• Immunohistochemistry for co-infection detection.

Main Results:

• Sarcocystis spp. cysts were found in 33% (11/33) of raptors, primarily in muscle tissues.
• No significant inflammation was associated with the detected Sarcocystis cysts.
• PCR analysis identified Sarcocystis falcatula in six raptors and Sarcocystis halieti in two.
• One Bald Eagle with Sarcocystis falcatula also exhibited encephalitis and eastern equine encephalitis virus.

Conclusions:

• Raptors in eastern Tennessee frequently harbor Sarcocystis species, consistent with findings elsewhere.
• The majority of Sarcocystis infections in this raptor population appear to be subclinical.
• Co-infections, such as Sarcocystis falcatula with EEEV, warrant further investigation in raptor health.