Molecular characterization of Aeromonas hydrophila isolates from diseased fishes in district Kasur, Punjab, Pakistan

Pakistan is an agricultural country and fisheries play a very important role in the economic development of the country. Different diseases are prevalent in Pakistani fish but information related to the causative agents is not well-known. Keeping in view the significance of bacterial pathogens as the causative agents of multiple fish diseases, the present study was conducted for identification, characterization and analysis of virulence genes of Aeromonas spp. isolated from diseased fishes. A total of fifty fish samples having multiple clinical indications were collected from different fish farms of district Kasur, Punjab Pakistan. For isolation of Aeromonas spp. samples were enriched and inoculated on Aeromonas isolation medium. Isolates were identified and characterized by different biochemical tests, Analytical Profile Index (API) 20E kit and Polymerase Chain Reaction (PCR) assays. All isolates were screened for three putative virulence genes including aerolysin (aer), haemolysin (hyl) and heat labile cytotonic enterotoxin (alt). Seven isolates of Aeromonas (A.) hydrophila were retrieved and identified based on API 20E. These isolates were further confirmed as A. hydrophila on the basis of PCR assays. Three isolates were detected positive for the presence of virulence genes (alt and hyl). Whereas aerolysin (aer) gene was not present in any of A. hydrophila isolates. The present study confirmed A. hydrophila as the causative agent of epizootic ulcerative syndrome and motile Aeromonas septicemia in fish farms of district Kasur, Punjab Pakistan. Moreover, detection of two virulence genes (alt and hyl) in A. hydrophila isolates is a threat for fish consumers of study area.

Wetlands, Fishes and Pandemics with Special Reference to India

Water is life, life is water. Water is indispensably important for sustenance of life. Wetlands serve as potential water bodies, harbouring coveted bioresources, which sustain animal life. Fish is a significant bioresource for nutrition and avocation of the people. There are various types of wetlands in the Indian sub-continent. India has c 67,429 wetlands covering c 4.1 million ha. Concomitantly, c 21,723 living species of fish have been recorded out of 39,900 species of vertebrates. Of these, c 8411 are freshwater (FW) species and c 11,650 are marine. India recorded c 2500 species of fishes; of which, c 930 live in FW and c 1570 are marine. The hitherto unknown dreadful, virulent, enigmatic Epizootic Ulcerative Syndrome (EUS), has been sweeping the FW fishes in an epidemic dimension, unhindered, unimpeded and unabated, almost semi-globally; and, has been causing large-scale mortality among them, since 1988, rendering many of them endangered. Concomitantly, the outbreak of SARS-CoV-2, among the human, was first reported at Wuhan, China, in late December 2019. The first 54 reported cases of COVID-19 were observed in December 2019 at Wuhan, China, and this, subsequently, had spread across the globe. India has been facing much impacts of COVID19 pandemic since its inception in China.

Epizootic Ulcerative Syndrome (EUS) Fish Disease Chronology, Status and Major Outbreaks in the World

Epizootic Ulcerative Syndrome (EUS) has been causing large-scale mortality among the freshwater fishes of the globe since the 1070s. The symptoms include large haemorrhagic cutaneous ulcers, epidermal degeneration and necrosis followed by sloughing of scales. There have been many studies on EUS throughout the world. In India, since the initiation of EUS, in 1988, our study tried to reveal the aetiology of the disease through extensive and intensive studies on different aspects, like limnological, physical, chemical, bacteriological, fungal, viral including electron microscopic studies. Details of EUS investigation has been discussed in the present paper.

Status of Aqua Drugs Applied in Freshwater Aquaculture of Moulvibazar District, Bangladesh

Aims: Our study aimed to assess the current situation of accessibility and the use of various chemicals and medicines in freshwater aquaculture. Methodology: A questionnaire interview survey was conducted among 14 aquaculture farms and 23 aqua chemical retailers. Results: Due to easy availability, farmers used large quantities of lime and cow dung to prepare ponds and manage water quality. Beside these rotenone, zeolite gold, acme’s zeolite, aqua kleen, urea and TSP (triple super phosphate) are also found. Timsen, polgard-plus, deltix, virex, magic-fos and pond-safe were mostly used as a disinfectant. Epizootic Ulcerative Syndrome (EUS) disease was found predominantly in the farmer's pond. For disease treatment, renamycine soluble powder (oxy tetracycline) was used, 32% farmers. Two oxygen suppliers oxy gold and oxy life were used to increase oxygen concentration. Among 11 types of growth promoters were found in chemical shops in which charger gel and rapid grow were mostly used. Most farmers use gas trap and gasonex plus as gas reducer. Conclusions: There are mostly six categories of 48 aqua drugs and chemicals are observed and treated for health monitoring of fish and shellfish. Due to lack of knowledge concerning the proper dosage and procedure of using chemicals, technique of application and indiscriminate practice of chemicals etc. are common problems of aqua drugs in Moulvibazar district.

Effect of EUS on Some haematological Paramaters of channa Straitus

Epizootic ulcerative syndrome (EUS) is such type of epidemic disease from which a number of fishes have been found to suffer since a long period. A great loss in fish farming is seen also. The paper deals about effect of such EUS disease on some haematological parameters of selected fish C. Straitus.

Epizootic ulcerative syndrome (EUS) prevention and control measures.

In Bangladesh, CARE, an international NGO working in development with agricultural and natural resource management as an important component, operated a project funded by the European Union to test the potential of farmer participatory research as a tool to improve the agricultural productivity of farmers. As part of the project activities, participatory action research groups were formed involving farmers with interest to work on the concept. Farmers were encouraged to identify their own farming problems and, based on the identified problems, farmers were assisted to develop their own strategies to solve their problems. Epizootic ulcerative syndrome (EUS) emerged as an important problem in aquaculture for farmers practicing carp culture. Based on the available information on the subject and in consultation with experts in the subject area, treatment strategies were developed by the farmers to manage this major disease, which occurs during the winter season from October to February. Lime, salt, a combination of lime and salt in a 1:1 ratio, or ash, were identified as potential treatment measures during the first year trials. Farmers agreed to apply lime and salt at the rate of 1 kg decimal-1 (1 decimal = 40 m2) as a primary dose followed by a fortnightly application at half the initial dose until the end of the season. Ash was applied at a higher dose of 3 kg 40 m-2 as a primary dose, followed by half the initial dose until the end of the season. A control group of farmers was also maintained within the Participatory Action Research Groups (PARGs). Farmers were not given any financial support for the purchase of inputs, but they were given technical support. Though all farmers did not follow the periodic application at the agreed level of chemicals, all the farmers had made more than one application. The results obtained at the end of first year with 315 farmers were highly encouraging, with good results obtained from the application of lime, salt, or ash. In addition to disease prevention, increase in fish production was noticed by the farmers as a result of application of these inputs to the pond. Following these initial encouraging results at field level, the Institute of Aquaculture, University of Stirling, UK, provided technical and monetary support to continue the study. The results conducted with another group of 232 farmers during second year confirmed the beneficial effects of lime, salt and ash and proved their popularity. In addition to the above treatments, two new treatments involving application of neem (Azadirachta indica) stems with leaves as well as application of adequate fertilisers to ensure green colour of water were also tried. The results confirmed the efficacy of lime, salt and ash as treatment materials to prevent the disease. Though neem stems were not highly effective, farmers were able to derive some relief, but the application of fertilisers to ensure adequate plankton production gave highly encouraging results. Many of these field results could not be replicated under laboratory conditions. Furthermore, a treatment that was effective in one pond did not have a similar effect in a neighbouring pond. These varied results support the view that individual pond ecology influences the effect of treatments adopted. It is thus advisable that every farmer should experiment with the successful treatments in their own pond environment to evolve suitable procedures. Most interestingly, ash, which is commonly available to most farmers as a non-purchased input, can be effectively used to prevent the disease as well as increase fish pond productivity.