Thammatorn Worrayanee, Rawiwan Pattarasuda, Surachetpong Win
Department of Veterinary Microbiology and Immunology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand.
Center for Advanced Studies for Agriculture and Food, Institute for Advanced Studies, Kasetsart University, Bangkok, Thailand.
J Fish Dis. 2019 Jan;42(1):3-9. doi: 10.1111/jfd.12924. Epub 2018 Nov 23.
Recent outbreaks of a novel tilapia lake virus (TiLV) have raised concerns regarding the international spread of TiLV in frozen tilapia products. This study investigated the potential risks of frozen tilapia fillet as a source of TiLV transmission. It revealed that TiLV genomic RNA could be detected in tilapia fillet and the virus isolated from non-frozen and frozen fillets with clinical TiLV infection stored up to 28 days caused a cytopathic effect (CPE) formation in the susceptible cell line in vitro. However, frozen fillets from clinical TiLV infection stored for 90 and 120 days did not cause CPE in the susceptible cell line. Similarly, CPE was not observed in TiLV isolated from subclinically TiLV-infected fish fillets. In addition, in vivo bioassay revealed that despite the presence of TiLV isolated from subclinically TiLV-infected fillet stored at -20°C for 14 days, there was no evidence of TiLV disease in naïve red hybrid tilapia based on the absence of clinical signs and mortality and without the detection of TiLV genomic RNA using reverse transcription-quantitative polymerase chain reaction assay. Collectively, these findings suggested minimal risk of transmission of TiLV via frozen tilapia fillets.
最近新型罗非鱼湖病毒（TiLV）的爆发引发了人们对TiLV在冷冻罗非鱼产品中进行国际传播的担忧。本研究调查了冷冻罗非鱼片作为TiLV传播源的潜在风险。研究发现，在罗非鱼片中可检测到TiLV基因组RNA，从临床感染TiLV的非冷冻和冷冻罗非鱼片中分离出的病毒，在储存长达28天的情况下，可在体外易感细胞系中引起细胞病变效应（CPE）。然而，临床感染TiLV的冷冻罗非鱼片在储存90天和120天时，在易感细胞系中未引起CPE。同样，从亚临床感染TiLV的鱼片中分离出的TiLV也未观察到CPE。此外，体内生物测定表明，尽管从在-20°C下储存14天的亚临床感染TiLV的鱼片中分离出了TiLV，但基于未出现临床症状和死亡率，且使用逆转录定量聚合酶链反应检测未检测到TiLV基因组RNA，在未感染的红罗非鱼中没有TiLV疾病的证据。总体而言，这些发现表明通过冷冻罗非鱼片传播TiLV的风险极小。
