Chayaburakul Kanokporn, Nash Gary, Pratanpipat Phusit, Sriurairatana Siriporn, Withyachumnarnkul Boonsirm
Department of Anatomy, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand.
Dis Aquat Organ. 2004 Aug 9;60(2):89-96. doi: 10.3354/dao060089.
In 2001-2002 throughout Thailand, black tiger shrimp Penaeus monodon farmers reported very unusual retarded growth. We have called this problem monodon slow growth syndrome (MSGS). Based on decreased national production, estimated losses due to this phenomenon were in the range of 13 000 million baht (approximately 300 million US dollars) in 2002. Since rearing practices had not changed, it was considered possible that the MSGS problem may have arisen from a new or existing pathogen. To examine this possibility, cultivated shrimp were sampled from 32 commercial rearing ponds that reported abnormally slow growth from eastern, central and southern regions of Thailand. Shrimp were randomly sampled from each pond and grouped into normal and small shrimp. Normal shrimp were defined as those with body weights (BW) of 24 g or more while small shrimp were defined as those that weighed 16.8 g or less. Pleopods were used for detection of monodon baculovirus (MBV), heptopancreatic parvovirus (HPV) and infectious hypodermal and hematopoietic necrosis virus (IHHNV) using specific polymerase chain reaction (PCR) assays. In addition, some shrimp were processed for normal histopathology and transmission electron microscopy (TEM). Most of the shrimp specimens were infected by at least 1 of these viruses but many had dual or multiple infections. Prevalence of HPV and combined HPV/MBV infections in the small shrimp was significantly higher than in the normal shrimp. In addition to the viruses, a new microsporidian species, gregarines and bacteria were also observed but were not significantly associated with the MSGS problem. Some of the small shrimp gave negative results for all these pathogens by PCR and histology and no new and unique histopathology was recognized in any of the samples. The findings suggested that HPV infection was a contributing factor but not the overriding factor responsible for MSGS. It is possible that MSGS is caused by an unknown pathogen or by some other presently unknown, non-pathogenic factor.
2001年至2002年期间，泰国各地的黑虎虾养殖户报告称，虾的生长出现了非常异常的迟缓现象。我们将这个问题称为斑节对虾生长迟缓综合征（MSGS）。根据全国产量下降情况估算，2002年因这一现象造成的损失在130亿泰铢（约3亿美元）左右。由于养殖方式没有改变，人们认为MSGS问题可能是由一种新出现的或现有的病原体引起的。为了检验这种可能性，从泰国东部、中部和南部地区32个报告生长异常缓慢的商业养殖池塘中采集了养殖虾样本。从每个池塘中随机抽取虾样本，并分为正常虾和小虾。正常虾定义为体重（BW）24克或以上的虾，而小虾定义为体重16.8克或以下的虾。使用特异性聚合酶链反应（PCR）检测法，利用腹肢检测斑节对虾杆状病毒（MBV）、肝胰腺细小病毒（HPV）和传染性皮下及造血组织坏死病毒（IHHNV）。此外，对一些虾进行了常规组织病理学和透射电子显微镜（TEM）检查。大多数虾样本至少感染了这些病毒中的一种，但许多样本存在双重或多重感染。小虾中HPV及HPV/MBV合并感染的发生率显著高于正常虾。除了病毒，还观察到一种新的微孢子虫物种、簇虫和细菌，但它们与MSGS问题没有显著关联。一些小虾通过PCR和组织学检测对所有这些病原体均呈阴性结果，且在任何样本中均未发现新的和独特的组织病理学特征。研究结果表明，HPV感染是一个促成因素，但不是导致MSGS的首要因素。MSGS有可能是由一种未知病原体或其他目前未知的非致病因素引起的。
