Gustafson L L, Ellis S K, Beattie M J, Chang B D, Dickey D A, Robinson T L, Marenghi F P, Moffett P J, Page F H
USDA APHIS, Veterinary Services, 16 Deep Cove Road, Eastport, ME 04631, USA.
Prev Vet Med. 2007 Jan 16;78(1):35-56. doi: 10.1016/j.prevetmed.2006.09.006. Epub 2006 Nov 9.
Infectious salmon anemia (ISA) has caused severe morbidity and mortality in farmed Atlantic salmon in North America, Norway, Scotland and the Faroe Islands. The Quoddy region of Maine, United States of America (USA), and New Brunswick (NB), Canada is characterized by extensive tidal mixing and close proximity between farms. This region is also prone to recurrent appearances of ISA, though control measures limit disease spread and severity on infected farms. We conducted a retrospective longitudinal analysis of the apparent impact of hydrographics on the incidence and timing of ISA outbreaks on Atlantic salmon (Salmo salar L.) farms in the Quoddy region from May 2002 to August 2004. A time-series cross-sectional regression of 32 farms over 28 months demonstrated a limited, but statistically significant, spatio-temporal clustering of ISA outbreaks linked hydrographically. New outbreaks correlated temporally with those occurring on-site 1 and 3 months prior, and those occurring within one tidal-excursion upstream the same month. Other risk factors included holdover of previous year-class fish, wharf sharing, and possibly harvests of cages infected in previous months. Conclusions suggest that tidal dispersion does play a role in ISAV transmission in the Quoddy region. Dispersal of free virus and/or tidal distribution of lice or other hydrographically influenced vectors or fomites could all contribute to the spatio-temporal patterns described.
传染性鲑鱼贫血症(ISA)已在北美洲、挪威、苏格兰和法罗群岛的养殖大西洋鲑鱼中造成了严重的发病和死亡情况。美国缅因州的夸迪地区以及加拿大的新不伦瑞克省(NB)的特点是潮汐混合广泛且养殖场之间距离很近。该地区也容易反复出现ISA,不过控制措施限制了疾病在受感染养殖场的传播和严重程度。我们对2002年5月至2004年8月夸迪地区大西洋鲑鱼(Salmo salar L.)养殖场水文地理因素对ISA疫情发生的频率和时间的明显影响进行了回顾性纵向分析。对32个养殖场在28个月期间进行的时间序列横断面回归分析表明,ISA疫情在水文地理上存在有限但具有统计学意义的时空聚集现象。新疫情在时间上与1个月和3个月前在现场发生的疫情以及同月在上游一个潮汐行程范围内发生的疫情相关。其他风险因素包括上一年龄组鱼的留存、码头共享以及可能在前几个月感染的网箱的收获情况。结论表明,潮汐扩散在夸迪地区ISA病毒传播中确实起到了作用。游离病毒的扩散和/或虱子或其他受水文地理影响的媒介或污染物的潮汐分布都可能导致所描述的时空模式。