Herpesviruses are common agents in animals of the aquatic environment. They infect many species of fish but only lead to disease in one or two species. Nevertheless, infected fish without clinical symptoms can actively transfer infectious agents to disease-susceptible species. The aim of the study was to identify and prove the natural presence of different herpesviruses.

Carp oedema virus (CEV) is a relatively understudied poxvirus. It exhibits an affinity for gill and skin epithelial cells. Investigations were conducted into selected aspects of CEV biology, with a focus on determining cell and tissue tropism of CEV, acquiring gene sequences and updating CEV tests in fish tissues.

Fish can be considered as an ideal food as it contains high protein content, minerals, vitamins and omega 3 fatty acids. Organochlorine pesticides (OCPs) are characterized by their low cost, severe toxicity against a wide array of pests, long duration of action and stability in the environment. OCPs have been used for many years in African countries, particularly in Egypt. Despite being outlawed everywhere, OCPs are still being used illegally. One of the main responsibilities of the food safety and public health sectors is to guarantee the safety and wholesomeness of such food products before they are made available to the general public. In order to determine the residual OCP contents in retailed tilapia, catfish, mullet, saurus, and pagrus, this study was conducted. The obtained results in the current investigation revealed the detection of OCPs at 80%, 50%, 20%, 15%, and 15% in the examined catfish, tilapia, mullet, saurus, and pagrus, respectively. Different OCPs were detected at variable concentrations; however, such concentrations were within the established permissible limits in Egypt. In conclusion, OCPs are still detected in different aquatic species and residual concentrations can be detected in different fish species retailed in the Egyptian fish markets. Therefore, it is highly advised to continuously check for OCP residues in fish.