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A sensitive PCR assay for the detection of Setaria digitata has been developed. Two oligonucleotide primers (17 nt) were designed from a previously cloned and characterized tandemly arranged repetitive sequence of Setaria digitata. Using these primers, it was possible to amplify small quantities (100 fg) of S. digitata genomic DNA. A simple procedure, using proteinase K and non-ionic detergent NP 40, was followed to process the host blood samples and mosquitoes harbouring L3 larvae. The sensitivity of the polymerase chain reaction based assay surpasses the microscopic detection and the previously reported oligonucleotide based chemiluminescent detection of microfilariae in infected host blood samples and L3 larvae in mosquitoes.

The central nervous systems of three wild moose (Alces a. americana) exhibiting neurologic signs, in the Kenora district of Ontario, Canada, were studied histologically. A diagnosis of cerebrospinal nematodiasis (Pneumostrongylus tenuis) was made in all three animals.

SUMMARY Fatal paralysis has occurred in beavers in the Dublin Zoological Gardens for some years, and it has been found impossible to raise this species to maturity. Immature worms or larvae which are probably ascarids appear to be the cause of a focal malacia of the brain and almost certainly account for the neuroparalytic signs. We have no idea what are the natural hosts of these parasites. The case adds to a growing list of diseases which are caused by helminth parasites migrating to the central nervous system of a great variety of mammalian hosts.

Six lambs were each infected experimentally with 50-1000 infective larvae of Pneumostrongylus tenuis. Three animals displayed neurologic signs. Lesions and dead or living worms were found in the central nervous system of all infected lambs. It is concluded, however, that sheep have a good natural resistance to infection and that P. tenuis will not mature in them. Before P. tenuis is diagnosed in naturally infected sheep it would be advisable to establish whether the sheep have been in contact with white-tailed deer, the normal host. Neurologic disease in sheep has been attributed to Pneumostrongylus tenuis in New York, New Hampshire (5, 7, 8), and Connecticut (6) on the basis of fragments of worms dissected from neural parenchyma and from parts of worms found on histological sections of the spinal cord. Apparently the caudal extremity of male worms, essential to sound identification, was not found. During the past few years we have infected a number of lambs with P. tenuis from white-tailed deer. The results of these experiments are described herein.