Health management in aquaculture

A textbook on diseases of cultured warmwater fish and shrimps in the Philippines. Eleven chapters cover essential information on the basic principles of disease causation, major diseases of cultured fish and crustaceans, particularly shrimps, and methods of prevention and control. Emphasis is made on major diseases that occur in the Philippines and other countries in the Asian region. Included also are topics on harmful algae, immunology and molecular biological diagnostic techniques.1st Ed

Diseases of milkfish

Although the history of Chanos chanos culture has been quite long, reports of major epizootics have been few. Trained manpower and disease diagnostic services in most milkfish growing areas have not been readily available. Hence, earlier reports of etiologic agents of these epizootics were limited mostly to direct microscopic examination of specimens. Significant disease cases reported were attributed to bacterial, myotic, parasitic, and toxic causes. Bacterial infections, primarily due to Vibrio sp., have been frequently associated with mortality. To a lesser, extent fungal infections have also been reported. Intoxication of stock in freshwater systems by Microcystis toxins has caused massive fish kills in Laguna de Bay, Philippines. In most instances, affected fish were predisposed by environmental stress incurred in handling storage and transport. The fry and fingerling stages seemed severely affected compared with the older stages. Control of these infections must include assessment of fish husbandry practices first, before the use of chemotherapeutic agents like antibiotics is considered

Viral diseases

Outbreaks of viral infections can cause massive mortalities among cultured fishes or shrimps. Water temperature and age of the fish or shrimps are significant factors that influence the development of viral infections. Most fish viral infections occur at low water temperatures, hence, very few viral infections among fishes in warm water culture systems are reported. In addition, most viral infections occur among fry or fingerlings often causing severe mortalities, while older fish or shrimp develop resistance or are hardly affected. Stress from handling, poor water quality, high stocking density and poor nutrition also affect the severity of viral infections. Finally, aquaculturists should beware in importing non-indigenous fish or shrimps into the country as these are potential carriers of viral pathogens

Prawn health in aquaculture

Disease management of intensively-cultured prawns requires an understanding of physiology and disease causation. Maladies result from an interaction of the prawn, disease agents and their environment. In intensive culture, the environment becomes increasingly difficult to control. Hence, surveillance for the early signs of disease, potential pathogens and the development of adverse environmental conditions should be integral components of a sound management system

Shrimp diseases in the Philippines: a historical perspective of research, training and development.

Pioneering research on shrimp diseases in the Philippines was spearheaded at the Aquaculture Department of the Southeast Asian Fisheries Development Center at Tigbauan, Iloilo in 1975. Investigations initially covered diseases of hatchery-bred shrimp fry and extensively-cultured shrimp juveniles which eventually extended to semi-intensive and intensive cultured shrimps. To date the following diseases of Penaeus monodon and other Penaeids in the Philippines were reported: Monodon Baculovirus (MBV) Disease, the Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV) Disease, Hepatopancreatic Parvo-like Virus (HPV) Disease, Yellow-head Virus (YHV) Disease, Spawner-isolated Mortality Virus Disease, Luminous Vibriosis, Other Vibrio Infections, Shell Disease, Filamentous Bacterial Disease, Chronic Soft Shell Syndrome, Blue Disease, Red Disease, Ascorbic Acid Deficiency Disease, Parasitic Infestations, Acid Sulfate Disease and Hypoxia. A summary of research findings on these diseases, their prevention and control are presented

Recent developments in the study and surveillance of koi herpesvirus (KHV) in Asia

Koi herpesvirus infection causes significant mortalities in common carp (Cyprinus carpio carpio), koi carp (Cyprinus carpio koi) and ghost carp (common x koi cross, Cyprinus carpio koi). Outbreaks have been reported in many countries worldwide i.e. UK, Germany, Israel, USA, Belgium, South Africa, Switzerland, The Netherlands, France, Denmark, Austria, Italy, Luxemburg and Poland. The first outbreaks attributed to KHV in Asian countries were reported from Hong Kong in 2001; Indonesia in 2002; Taiwan in 2002; Japan in 2003; Thailand in 2005; and Singapore in 2005. Thereafter, research studies embarked on KHV focused on pathogenicity, cell line susceptibility, fish size susceptibility, predilection to fish organs, persistence in fish, vaccine development and application, surveillance and gene sequence analyses of KHV strains. To date, annual active surveillance of the virus in Cambodia, Lao PDR, Myanmar, the Philippines and Vietnam showed that these countries were free of KHV from 2004 to 2007. Several strains of KHV apparently affect koi and common carp in this region indicating that transboundary movement of the virus has occurred not only in Asia but also from Europe and the Americas. The extensive international trade in live ornamental koi fish has largely contributed to the global spread of KHV. Hence, KHV disease (KHVD) was recently added to the list of notifiable diseases of the World Organisation of Animal Health or the Office International des Epizooties (OIE), an indication of the global significance of this viral infection

Viral diseases

Outbreaks of viral infections can cause massive mortalities among cultured fishes or shrimps. Water temperature and age of the fish or shrimps are significant factors that influence the development of viral infections. Most fish viral infections occur at low water temperatures, hence, very few viral infections among fishes in warm water culture systems are reported. In addition, most viral infections occur among fry or fingerlings often causing severe mortalities, while older fish or shrimp develop resistance or are hardly affected. Stress from handling, poor water quality, high stocking density and poor nutrition also affect the severity of viral infections. Finally, aquaculturists should beware in importing non-indigenous fish or shrimps into the country as these are potential carriers of viral pathogens

Summary brief: International symposium on koi herpesvirus diseases

The Koi Herpesvirus Disease (KHVD) is the newest viral disease that caused mass mortalities of affected koi and common carp (Cyprinus carpio). The disease was initially reported in Israel and the United States in 2000. By March 2002, the first outbreak in Asia occurred in Indonesia that since then spread throughout the country. In early October 2003, KHVD outbreaks in Japan were first observed in Lake Kasumigaura and Kitaura of Ibaraki Prefecture.With the alarming spread of KHVD in Asia, strategies for its prevention and control need to be initiated. Hence, on 13 March 2004, the Fisheries Research Agency (FRA) of Japan, the Southeast Asian Fisheries Development Center (SEAFDEC), the Ministry of Agriculture, Forestry and Fisheries (MAFF) of Japan and the World Organisation for Animal Health (OIE) organized the "International Symposium on Koi Herpesvirus Disease" in Yokohama, Japan. It was a forum participated in by scientists from Japan, SEAFDEC member countries, United States, East Asia, Israel and Europe to exchange the latest information on the disease and its prevention and control