Larrat Sylvain, Bouchard Francis, Séguin Guylaine, Lair Stéphane
Canadian Cooperative Wildlife Health Center/Centre québécois sur la santé des animaux sauvages, Faculté de médecine vétérinaire, Université de Montréal, 3200, rue Sicotte, St. Hyacinthe, Quebec, Canada J2S 2M2.
J Wildl Dis. 2013 Apr;49(2):229-34. doi: 10.7589/2011-10-299.
The pathogenesis of the recently recognized "red vent syndrome" in wild Atlantic salmon (Salmo salar) is not fully understood. Pathologic observations indicate that this syndrome is associated with the presence of nonencapsulated larvae of the nematode Anisakis simplex in the body wall, the lower intestinal wall, and the visceral cavity surrounding the vent region. We evaluated the relationship between the occurrence of red vent syndrome and intensity of infection with Anisakis sp. larvae in naturally infected fish. Salmon caught by sport anglers were opportunistically evaluated to detect red vent syndrome. We included 106 salmon with red vent syndrome and 98 without red vent syndrome in this study. Intensity of infection was established by counting the total number of perivisceral larvae and by determining the number of larvae per gram in 10 g of pepsin-digested perianal tissue. The severity of inflammatory changes was also evaluated in standard histologic sections of the perianal area using a semiquantitative scale. Salmon with red vent syndrome had significantly higher intensity of inflammation than salmon without red vent syndrome (P=0.008). The odds of having red vent syndrome increased with the number of perianal larvae per gram of perianal tissue (P=0.002; odds ratio [OR]=1.12; 95% confidence interval: [1.05; 1.22]) but not with the number of perivisceral larvae, fish length, or gender. Although these results support the association between this syndrome and intensity of infection by A. simplex, the relationship is not strong (OR near 1), suggesting that the clinical expression of red vent syndrome at an individual level, and the emergence of this disease on a global scale, must be determined by other factors, such as timing of infection.
野生大西洋鲑鱼（Salmo salar）中最近发现的“红泄殖腔综合征”的发病机制尚未完全明确。病理观察表明，该综合征与线虫简单异尖线虫（Anisakis simplex）的非包囊幼虫存在于体壁、下肠壁以及泄殖腔区域周围的内脏腔有关。我们评估了自然感染鱼类中红泄殖腔综合征的发生与异尖线虫属幼虫感染强度之间的关系。对休闲垂钓者捕获的鲑鱼进行机会性评估以检测红泄殖腔综合征。本研究纳入了106条患有红泄殖腔综合征的鲑鱼和98条未患红泄殖腔综合征的鲑鱼。通过计算内脏周围幼虫的总数以及确定10克经胃蛋白酶消化的肛周组织中每克的幼虫数量来确定感染强度。还使用半定量量表在肛周区域的标准组织学切片中评估炎症变化的严重程度。患有红泄殖腔综合征的鲑鱼的炎症强度明显高于未患红泄殖腔综合征的鲑鱼（P = 0.008）。每克肛周组织中肛周幼虫数量越多，患红泄殖腔综合征的几率就越高（P = 0.002；优势比[OR]=1.12；95%置信区间：[1.05；1.22]），但与内脏周围幼虫数量、鱼的长度或性别无关。尽管这些结果支持了该综合征与简单异尖线虫感染强度之间的关联，但这种关系并不强（OR接近1），这表明红泄殖腔综合征在个体水平上的临床表现以及该疾病在全球范围内的出现，必定由其他因素决定，例如感染时间。
