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Here we present the draft genome sequence of Setaria digitata, a parasitic nematode affecting cattle. Due to its similarity to Wuchereria bancrofti, the parasitic nematode that causes lymphatic filariasis in humans, S. digitata has been used as a model organism at the genomic level to find drug targets which can be used for the development of novel drugs and/or vaccines for human filariasis. Setaria digitata causes cerebrospinal nematodiasis in goats, sheep, and horses posing a serious threat to livestock in developing countries. The genome sequence of S. digitata will assist in finding candidate genes to use as drug targets in both S. digitata and W. bancrofti. The assembled draft genome is ∼90 Mb long and contains 8,974 genomic scaffolds with a G+C content of 31.73%.

Setaria digitata is a filarial parasite that causes fatal cerebrospinal nematodiasis in goats, sheep and horses, resulting in substantial economic losses in animal husbandry in the tropics. Due to its close resemblance to Wuchereria bancrofti, this nematode is also frequently used as a model organism to study human lymphatic filariasis. This review highlights numerous insights into the morphological, histological, biochemical, immunological and genetic aspects of S. digitata that have broadened our understanding towards the control and eradication of filarial diseases.

A case of cerebrospinal nematodiasis in a young adult moose (Alces alces) from Telemark county, southeastern Norway, is described. The moose was found by bird hunters during January, displaying signs of severe posterior paresis. It was killed and submitted for autopsy. The carcass was emaciated, and there were skin excoriations and subcutaneous edema over both metacarpi. Histopathologic examination revealed traumatic malacia throughout the spinal cord and meningeal accumulations of mononuclear inflammatory cells and eosinophils in brain and spinal cord. Two adult female nematodes were found in sections, respectively, of the subarachnoid and subdural spaces of the thoracic spinal cord. The nematode cross sections were similar with those of the two neurotropic Elaphostrongylus species, E. rangiferi and E. cervi. The moose originated from an area overlapping the grazing area of a large population of wild reindeer (Rangifer tarandus tarandus) living on the mountain plateau of Hardangervidda, suggesting the moose was infected with E. rangiferi from reindeer.

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.

During a telemetry study conducted between 1993 and 1995 in east-central Kansas (USA) on northern bobwhite (Colinus virginianus) populations, a wild adult male quail was found with signs of disorientation and torticollis in August 1994 in Lyon County, Kansas. Based on histological and parasitological examination, it was determined that the bird was infected with larval nematodes of the genus Baylisascaris spp. This is the first known recorded case of Baylisascaris sp. in a wild game bird species.

A natural infection of meningeal worm (Parelaphostrongylus tenuis) accounted for the death of 11 of 17 (65%) Angora goats in a study in South Texas during 1975. Clinical signs, gross pathology and histopathology in Angoras were similar to other abnormal hosts.

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.

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.