ABSTRACT
Equine protozoal myeloencephalitis is an important neurological disease of horses in the United States. Consequently, there is an active research effort to identify hosts associated with the primary causative agent, Sarcocystis neurona. The purpose of this study was to determine whether the domestic cat (Felis catus) is a natural host for S. neurona. Muscle sections from 50 primarily free-roaming domestic cats were examined for the presence of sarcocysts. Serum from cats in this group and another group of 50 free-roaming cats were evaluated for the presence of S. neurona antibody. Sarcocysts were found in five of 50 (10%) cats, and S. neurona antibody in five of 100 (5%) cats. Morphological, molecular (including ribosomal RNA genes), and biological characterisation of these sarcocysts showed that they were not S. neurona or S. neurona-like. Sarcocysts found in the cats were identified morphologically as Sarcocystis felis, a common parasite of wild felids. The life cycle of S. felis is not known, and prior to this study, no molecular marker for S. felis existed. Although cats were found to be infected with S. felis sarcocysts, serological data provided evidence of possible infection with S. neurona as well. Further work is needed to determine the role of the domestic cat in the life cycle of S. neurona.
Subject(s)
Cat Diseases/parasitology , Sarcocystis/isolation & purification , Sarcocystosis/veterinary , Animals , Antibodies, Protozoan/blood , Cats , DNA, Protozoan/genetics , Disease Vectors , Muscle, Skeletal/parasitology , Sarcocystis/classification , Sarcocystis/immunology , Sarcocystis/ultrastructure , Sarcocystosis/parasitologyABSTRACT
Sarcocysts were dissected from the tongue of a nine-banded armadillo (Dasypus novemcinctus). DNA was extracted and characterised by PCR amplification followed by restriction fragment length polymorphism analysis and nucleotide sequencing. A total of 1879 nucleotides were compared; the sarcocyst DNA sequence was identical to that reported for Sarcocystis neurona. DNA was extracted from the sarcocysts of five more nine-banded armadillos. A 254-nucleotide sequence was determined for each and found to be identical to S. neurona. Western blot techniques for detection of anti-S. neurona antibody were developed for use with armadillo plasma and samples from 19 wild-caught and 17 captive-raised armadillos were examined. Whereas all of the 19 wild-caught armadillos had antibodies to S. neurona, only one of 17 captive-raised armadillos did. These results suggest that the nine-banded armadillo are naturally infected with S. neurona.
