EXPERIMENTAL STUDIES OF ELAPHOSTRONGYLUS-RANGIFERI IN REINDEER (RANFIFER-TARANDUS-TARANDUS) - LIFE-CYCLE, PATHOGENESIS, AND PATHOLOGY

A total of 12 reindeer calves (Rangifer tarandus tarandus) were given 200-1,000 infective larvae of Elaphostrongylus rangiferi and autopsied 2 1/2-196 days post inoculation (p.i.). The larvae penetrated venules of the abomasal wall and followed the bloodstream via the liver to th e lungs. In the lungs the larvae entered pulmonary venules and spread to all tissues via the general circulation. Many larvae that lodged in arterial vessels outside the spinal cord migrated into the cord along the spinal nerves. Nematodes matured in the central nervous system (C NS), and then migrated to the skeletal muscles (SM) via the spinal ner ve roots. Eggs were deposited into veins and carried via the venous bl ood to the lungs. Here, the first stage larvae hatched and entered the airways. Pathological lesions consisting of focal necroses and inters titial accumulations of inflammatory cells were observed in the abomas al wall, liver, lungs, myocardium and kidneys. Infarcts were observed in the myocardium, kidneys and CNS. Other lesions in the nervous syste m were encephalomyelitis, focal traumatic encephalomyelomalacia, axon and myelin sheath degenerations, meningitis, chorioditis, perineuritis , neuritis and ganglioradiculitis. A multifocal verminous pneumonia pe rsisted from day 103 p.i., and nematode-induced inflammatory oedema wa s observed in the intermuscular connective tissue of the SM at 196 day s p.i.