RESUMEN
Pathology records from the State Veterinary Laboratory for Northern Norway were used to examine the association between the occurrence of cerebrospinal elaphostrongylosis (CSE) in small ruminants and summer temperature and rainfall in northern Norway. From 1968 to 1993, Elaphostrongylus rangiferi induced CSE was diagnosed in six sheep and 30 dairy goats from 28 different herds in northern Norway. The animals were received for autopsy during 11 different winters. The occurrence of CSE was associated with high mean temperatures during the preceding summers. Further information on clinical CSE and potential risk factors of the disease was obtained from small-ruminant farmers in northern Norway in 1989 and 1991, using a questionnaire. Clinical CSE was defined as posterior paresis without any evidence of brain disturbances or cranial nerve dysfunctions. The survey showed that epidemics of CSE may occur in goat herds while the occurrence of CSE was sporadic in sheep herds. Disease incidence in affected goat herds varied between 0.8 and 8.2%. CSE was associated with the presence of reindeer in the pasture area and occurred in the first, third and, especially, the fourth quarter of the year.
Asunto(s)
Enfermedades del Sistema Nervioso Central/veterinaria , Enfermedades de las Cabras/epidemiología , Metastrongyloidea , Enfermedades de las Ovejas/epidemiología , Infecciones por Strongylida/veterinaria , Animales , Enfermedades del Sistema Nervioso Central/epidemiología , Enfermedades del Sistema Nervioso Central/parasitología , Cabras , Incidencia , Noruega/epidemiología , Factores de Riesgo , Ovinos , Infecciones por Strongylida/epidemiologíaRESUMEN
Seven lambs were inoculated with 150-3,000 infective larvae of Elaphostrongylus rangiferi and subsequently killed for autopsy. From one week post inoculation (p.i.), a marked eosinophilia was found, and one of the lambs showed signs of coughing, increased respiratory frequency and elevated body temperature. Pruritus was observed in three lambs during the period 5-10 weeks p.i. Gross and microscopic lesions were found in the liver, lungs, myocardium, kidneys, spinal nerve roots and in the central nervous system (CNS). The lesions resembled those previously reported in experimentally infected goat kids. The migratory route of the infective larvae seemed to be haematogenous. Developing nematodes were sectioned in the CNS of a lamb killed at day 30 p.i. The nematodes found in the brain of this lamb were significantly thicker than those observed in the spinal cord. Intact nematodes were not detected in the remaining lambs which were all killed 149-151 days p.i. None of the experimental lambs shed E. rangiferi first-stage larvae in the faeces. These findings indicate that E. rangiferi gradually dies out in sheep and will not complete its life cycle in this animal species.