Prevalance, spread and control of caprine arthritis-encephalitis virus in dairy goat herds in New South Wales.

摘要

A study of the prevalence, spread and control of caprine arthritis-encephalitis virus (CAEV) in New South Wales during 1986-1988 found that 56.8% of 1484 goats in 14 dairy herds were infected with CAEV. At the end of the study, 59.7% of 1322 goats were infected. The prevalence of CAEV infection increased with age and in most herds that did not implement control measures. Differences between breeds were less apparent. Within 7 herds with a high standard of identification of goats, 149 of 812 goats seroconverted in ELISA. Of these newly infected goats, 142 (95.3%) were >1 year of age and 96 (64.4%) >2 year suggesting lateral spread of the virus. Most of the goats >2 year of age had been in the milking herd for a minimum of 3 to 6 months. The high seroconversion rate within the milking herd suggested that factors other than the ingestion of infected colostrum and milk before weaning were important for the spread of CAEV. Observations indicated that behaviour of goats, particularly reproductive behaviour among lactating goats, and milking herd management practices were important for spreading CAEV. A high density of livestock, poor livestock control and contamination of feed, water, equipment and personnel were implicated in transmission. Poorly functioning milking machines may also be involved. CAEV was eradicated from 3 herds by the implementation of strict control measures.