Submitted to: Parasitology International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 1, 2005
Publication Date: October 6, 2005
Citation: Sreekumar, C., Vianna, M., Hill, D.E., Miska, K.B., Lindquist, A., Dubey, J.P. 2005. Differential detection of hammondia hammondi from toxoplasma gondii using polymerase chain reaction. Parasitology International. 54(4):267-269.
Interpretive Summary: Toxoplasma gondii is a single-celled parasite of all warm-blooded hosts worldwide. It causes mental retardation and loss of vision in children, and abortion in livestock. Cats are the main reservoir of T. gondii because they are the only hosts that can excrete the resistant stage (oocyst) of the parasite in the feces. Humans become infected by eating undercooked meat from infected animals and food and water contaminated with oocysts.
Scientists at the Beltsville Agricultural Research Center describe molecular methods to distinguish oocysts of T. gondii from the related parasite, Hammondia hammondi also present in cat feces.The results will be of interest to biologists, parasitologists, and veterinarians
Hammondia hammondi and Toxoplasma gondii are two related coccidian parasites, with cats as definitive hosts and warm-blooded animals as intermediate hosts. It is difficult to differentiate them by morphological and serological parameters. In the present study primers were designed to specifically amplify the ITS-1 region of H. hammondi to differentiate it from T. gondii. Attempts were made to detect the presence of H. hammondi DNA in the tissues of mice infected with H. hammondi alone, as well as from mixed infections with T. gondii, using the newly designed primers. The de novo primers effectively amplified the H. hammondi-specific target fragment from all samples containing H. hammondi, including those with concomitant T. gondii infection. Further, the primers did not amplify any fragment from the related parasites like T. gondii, Neospora caninum and Hammondia heydorni. The new primers provide simple and efficient means to differentially diagnose H. hammondi from T. gondii even in samples containing both parasites, thus obviating the need for other labourious techniques like mouse bioassay and in vitro cultivation.