Heterakis gallinarumis a widely distributed cecal nematode that parasitizes gallinaceous birds including chickens and turkeys. H. gallinaruminfection poses a problem for the poultry industry as the nematode egg serves as avector for the protozoan parasite,Histomonas meleagridis, the causative agent of histomonosis. The only means ofdetectingH. gallinarumin the environment is microscopic identification of the eggs in soil or feces; however,H.gallinarumeggs are often mistaken for those ofAscaridia galli. Three primer sets were designed from sequencescloned from theH. gallinarumgenome to develop a diagnostic PCR. Each of these primer sets amplified a singleproduct fromH. gallinarum, but were unable to amplify DNA fromH. meleagridis,Ascaridia galli,orCestodesp.H.gallinarumDNA was amplified fromLumbricussp. (earthworms) andAlphitobius diaperinus(darkling beetles),confirming that the earthworm acts as a paratenic host forH. gallinarumand suggesting that the darkling beetlemay be a carrier for this nematode