Co-infections commonly arise when two or multiple different pathogens infect the same host, either as simultaneous or as secondary concurrent infection. This potentiates their pathogenic effects and leads to serious negative consequences on the exposed host. Numerous studies on the occurrence of the bacterial, parasitic, fungal and viral co-infections were conducted in various tilapia species. Co-infections have been associated with serious negative impacts on susceptible fish because they increase the fish susceptibility to diseases and the likelihood of outbreaks in the affected fish. Co-infections can alter the disease course and increase the severity of disease through synergistic and, more rarely, antagonistic interactions. In this review, reports on the synergistic co-infections and their impacts on the affected tilapia species are highlighted. Additionally, their pathogenic mechanisms are briefly discussed. Tilapia producers should be aware of the possible occurrence of co-infections and their effects on the affected tilapia species and in particular of the clinical signs and course of the disease. To date, there is still limited information regarding the pathogenicity mechanisms and pathogen interactions during these co-infections. This is generally due to low awareness regarding co-infections, and in many cases, a dominant pathogen is perceived to be of vital importance and hence becomes the target of treatment while the treatment of the co-infectious agents is neglected. This review article aimed at raising awareness regarding co-infections and helping researchers and fish health specialists pay greater attention to these natural cases, leading to increased research and more consistent diagnosis of co-infectious outbreaks in order to improve control strategies to protect tilapia when infected with multiple pathogens.

中文翻译：

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罗非鱼共感染的性质和后果：综述。

当两种或多种不同的病原体同时感染或继发并发感染时，共同感染通常会出现。这增强了它们的致病作用，并导致对暴露宿主的严重负面影响。在各种罗非鱼种类中进行了有关细菌，寄生虫，真菌和病毒共感染发生的大量研究。共同感染已对易感鱼类产生了严重的负面影响，因为它们会增加鱼类对疾病的易感性以及在受影响的鱼类中爆发疾病的可能性。合并感染可通过协同作用（更罕见的是拮抗作用）改变疾病进程并增加疾病的严重性。在这篇评论中 报告着重介绍了协同协同感染及其对罗非鱼种类的影响。此外，简要讨论了它们的致病机制。罗非鱼生产者应了解可能发生的合并感染及其对受影响罗非鱼种类的影响，尤其是该疾病的临床体征和病程。迄今为止，关于这些共感染期间的致病机理和病原体相互作用的信息仍然有限。这通常是由于对共感染的认识不足，在许多情况下，主要病原体被认为是至关重要的，因此在忽略共感染剂的治疗的同时成为治疗的目标。