Quality biological sampling is a fundamental requirement for all kinds of work on diagnosing diseases and screening for pathogens. Fish sampling requires specific techniques and skills to collect good biological samples for accurate disease diagnosis. This package of practices developed by WorldFish and partners provides advice on fish sampling protocols for routine disease diagnostics and outbreak investigations in tilapia, carp and catfish production systems. These sampling protocols provide guidance and training to project team members, researchers, resident veterinarians, extension officers and farmers tasked with collecting quality biological samples for laboratory diagnosis whenever disease outbreaks occur on farms or hatcheries. A free online introductory course on fish sampling for disease diagnostics is also available via Learn.ink.

To assist shrimp pathologists worldwide we are providing here photomicrographs of unique basophilic inclusions that are produced by Wenzhou shrimp virus 8 (WZV8),  discovered in 2015 by Li et. al. We designed PCR primers and in situ hybridization probes for detection of WZV8. Subsequent ISH assays with shrimp RT-PCR positive for WZV8 samples indicate unique inclusions described herein as linked to WZV8 in H&E stained tissues. Going back over our previous histological reports and archived slides, we have found the unique WZV8 inclusions in E-cells of normal shrimp samples from several shrimp farming countries in Austral-Asia since at least 2008, and more recently in samples of P. vannamei from the Americas. We urge shrimp pathologists to review their records and specimens for the presence of WZV8 E-cell inclusions described herein to provide data on the global prevalence and impact of WZV8-like infections.

In 2015, a bacterium called Streptococcus agalactiae, also referred to as Group B Streptococcus (GBS), caused a foodborne disease outbreak involving at least 146 people in Singapore, associated with the consumption of raw freshwater fish. The specific strain responsible for the outbreak was later identified as sequence type 283 (ST283). Invasive GBS ST283 disease is also found in other countries in and around Southeast Asia. FAO has published a fact sheet and a risk profile for GBS ST283, which are available for free download. These documents provide guidance on risk reduction, and practical recommendations for food safety competent authorities.

This disease advisory describes the history, known host range, clinical signs and PCR detection methods for viral covert mortality disease (VCMD). Crustaceans currently known to be susceptible to VCMD include Penaeus vannamei, P. chinensis, P. japonicus, P. monodon, Macrobrachium rosenbergii, Procambarus clarkii, Exopalaemon carinicauda, Ocypode cordimanus, Diogenes edwardsii, Corophium sinense, Parathemisto gaudichaud and Tubuca arcuate. Fish species including Mugilogobius abei, Carassius auratus, and Paralichthys olivaceus may also be susceptible to the virus.

Infection with DIV1 is an emerging disease in farmed Cherax quadricarinatus and Penaeus vannamei suffering a high mortality. This disease card provides information on signs of disease at pond and animal level (levels I - III diagnoses), the disease agent, known host range and distribution in the Asia-Pacific region, molecular diagnostic methods and provides key expert contact points.