Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 10, 2003
Publication Date: July 20, 2003
Citation: Sreekumar, C., Hill, D.E., Fournet, V.M., Rosenthal, B.M., Lindsay, D.S., Dubey, J.P. 2003. Detection of hammondia heydorni-like organisms and their differentiation from Neospora caninum using RAPD-PCR. Journal of Parasitology. 89:1082-1085.
Interpretive Summary: Neospora caninum is a single-celled parasite of livestock and companion animals. It causes abortion in livestock and paralysis in dogs. Dogs are the only reservoir hosts for this parasite because they pass a resistant stage (oocyst) in their feces. Differentiation of N. caninum oocysts is a problem. Scientists at Beltsville Agriculture Research Center and Virginia Tech, Blacksburg, Virginia, have developed a method to distinguish N. caninum oocysts from a related parasite, Hammondia heydorni. These results will be of interest to parasitologists, biologists and veterinarians.
Neospora caninum and Hammondia heydorni are morphologically and phylogenetically related coccidians that are found in dogs. New diagnostic genetic loci, based on random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR), were developed to aid in the detection of H. heydorni-like parasites and to discriminate them from N. caninum and other related coccidians of dogs. Based on the data obtained from 5 random decamers, H. heydorni (Manhattan-1) and N. caninum (NC1) were characterized by distinct banding patterns (similarity index = 0.068). High stringency PCR assays were developed from the sequences of 2 cloned bands (Genbank accession numbers BZ592549 and BZ592593), uniquely amplified from H. heydorni. Interestingly, using these primers, PCR amplification was achieved only from 2 of the 5 isolates presumed to represent H. heydorni. The same result was obtained from these 5 isolates using a recently described PCR assay directed to the H. heydorni internal transcribed spacer (ITS)-1. It is concluded that H. heydorni and N. caninum are genetically distinct and that such tools may be useful for more detailed characterization of the diversity of related parasites occurring in dogs.