Cholera is an ancient and widespread infectious disease, mainly manifested as severe vomiting, diarrhea, water loss, and high mortality. It belongs to the group of international quarantine infectious diseases, and Vibrio cholerae is the pathogen of human cholera. Since 1817, there have been seven global cholera pandemics, which have caused hundreds of millions of human deaths. The cause of these cholera epidemics is highly complex; how it spreads globally and the reason for seasonal epidemic peaks in epidemic areas remains unclear. Most sporadic outbreaks of cholera are related to aquatic products or related water bodies.

Bullfrog is one of the most important economic aquatic animals in China. It is widely cultured in southern China, and is a key breed recommended by China's poverty alleviation industry. In recent years, a fatal bacterial disease often occurs in cultured bullfrogs. The clinical manifestations of diseased bullfrog were severe intestinal inflammation and even anal prolapse. A bacterial pathogen was isolated from the diseased bullfrog intestine. The bacterium was identified as Vibrio cholerae by morphological, biochemical and 16S rRNA phylogenetic analysis. In this study, V. cholerae was isolated and identified from the diseased bullfrog for the first time, which provided the basis for the diagnosis and control of the disease. At the same time, it is also reminded that V. cholerae from bullfrog may be transmitted to human through bullfrog food and aquaculture water, which is a serious threat to human beings. The whole society should pay attention to it and formulate reasonable measures to avoid disasters.

Bluegill sunfish is an important economic fish, which originated in North America. It was introduced to China in 1987 and is now widely cultivated in Guangdong Province. In recent years, a fatal bacterial disease often occurs in cultured bluegill sunfish. The clinical manifestations of the diseased bluegill sunfish were ulceration and hyperemia. A bacterial pathogen was isolated from the viscera of diseased fish. It was identified as Vibrio cholerae by morphological, biochemical and 16S rDNA phylogenetic analysis. The regression infection experiment confirmed that the isolated strains could cause the disease of healthy bluegill sunfish. In this study, Vibrio cholerae was isolated and identified from diseased bluegill sunfish for the first time, and it provides a basis for the diagnosis, prevention and treatment of the disease. At the same time, this study proposed three ways for the transmission of Vibrio cholerae from aquatic animals to human beings, warning that we need to pay attention to the serious harm that the zoonotic bacteria in aquatic animals may cause to human beings, hoping to attract the attention of the whole society, so as to formulate effective countermeasures.

Hirudo nipponia is not only an important economic pillar for farmers, but is also a precious raw material for medicinal materials. However, in recent years, H. nipponia suffered from diseases with symptoms including systemic edema and hyperemia. It has not yet been demonstrated which pathogen causes this disease and whether this could be transmitted to humans. In this study, Klebsiella pneumoniae was isolated and identified from diseased H. nipponia and the pathogenicity of the isolated strain was confirmed. Furthermore, by comparing the sequence of the pathogen isolated from leeches to the same pathogen infecting humans, we identified that the isolated strain is a threat to human health. This work emphasizes the importance of the first discovery of pathogenic bacteria from leeches similar to human pathogens, as well as the need for identifying comorbidities for both humans and aquatic animals.