Prevalence of ‘milky disease’ caused by Metschnikowia bicuspidata in Eriocheir sinensis in Panjin city, China

Experimental Transmission of the Yeast, Metschnikowia bicuspidata, in the Chinese Mitten Crab, Eriocheir sinensis

“…Owing to the metamorphosis and rapid development of the larval stage, an infection experiment of the larval stage was not included in this investigation, and further studies are required to determine whether infection with M. bicuspidata is possible during the metamorphosis stage. A previous investigation demonstrated that the infection rate in young crabs was low, but the infection rate in the adult stage was high [10], which is consistent with the observations in M. rosenbergii [16], although the reason for the high rate of infections in adults remains unclear. Chen et al [16] postulated that despite adults having a more mature immune defense system, they are more likely than young shrimp to encounter yeast in pond water or sediment because they have a longer life span and tend to consume dead or dying shrimp that have been infected with the yeast.…”

“…Through comparing the three modes of infection, the infection rate of the group that was fed infected tissue was higher than the bath immersion and cohabitation groups, suggesting that cannibalism is more likely to result in infection. The survey of juvenile crabs and berried crabs in the overwintering ponds in the Panjin area also revealed that the infection rate was high [10]. This may be related to the high-density culture under the ice during the overwintering period, without access to shelter, which results in the cannibalism of infected crabs.…”

“…The Chinese mitten crab, Eriocheir sinensis, is an important farmed crustacean species in China, with 778, 682 tons produced in 2019 [9]. An emerging disease, which is commonly known as "milky disease", occurred in E. sinensis farms in Panjin city, northeast China, in the winter of 2018 [10]. The symptoms of diseased crabs were characterized by opaque whitish muscles and milky hemolymph, inactive and anorexic behavior, and staying at the shallow end of the pond.…”

Comparative Genomic Analyses Provide Insight Into the Pathogenicity of Metschnikowia bicuspidata LNES0119

“…For example, an outbreak of M. bicuspidata in Taiwan from May 2001 to December 2003 resulted in cumulative mortality rates of 20–95% in M. rosenbergii (see Chen et al, 2003 , 2007 ), 40–60% in P. trituberculatus in Zhoushan, Zhejiang Province, China, from 2002 to 2006 ( Shi et al, 2008 ), over 20% in E. sinensis in Panjin, Liaoning Province, China, from 2018 to 2019 ( Bao et al, 2021 ), and 34.5% in larval chinook salmon fed on infected Artemia in California, United States ( Moore and Strom, 2003 ). The aquatic hosts were infected directly by ingesting M. bicuspidata spores or indirectly by consuming diseased individuals, after which the spores in the body cavity began producing hyphae and adhered to nearby surfaces, producing conidia that rapidly increased in abundance within the host ( Merrill and Cáceres, 2018 ; Jiang et al, 2022 ; Sun et al, 2022 ).…”

“…This epidemic showed the characteristic symptoms of milky hemolymph and death due to organ failure. A milky disease epidemic was also detected in Xinjiang, Heilongjiang, and Jilin provinces, and the mortality rates in 2021 were even higher than that in 2020, which had seriously affected the Chinese mitten crab industry ( Sun et al, 2022 ). Therefore, in this study, the whole-genome sequence of the strain M. bicuspidata LNES0119 was sequenced using Illumina and Oxford Nanopore technology.…”