Disease library

A collection of technical publications relating to aquatic animal disease prevention, diagnosis and treatment.

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NACA publishes a wide range of aquaculture publications including technical manuals, workshop proceedings, better practice guidelines and several serials including Aquaculture Asia Magazine, the NACA Newsletter and the Quarterly Aquatic Animal Disease Report. To keep up to date with developments you could consider subscribing to our free email newsletter service and RSS feed

In this collection

Disease advisory: Tilapia lake virus - an emerging threat to farmed tilapia in the Asia-Pacific region

Tilapia lake virus (TiLV) is an emerging disease of cultured tilapia in the Asia-Pacific region. Originally observed and reported in Israel, Ecuador, Colombia and Egypt, TiLV is now confirmed in cultured tilapia in Thailand causing mass mortalities. At risk is here is the US$7.5 billion global industry per annum, especially among the top tilapia-producing countries in the region including China, the Philippines, Thailand, Indonesia, Lao PDR and Bangladesh. This advisory describes signs of the disease and PCR detection methods.

A warning and an improved PCR detection method for tilapia lake virus (TiLV) disease in Thai tilapia farms

Tilapia lake virus (TiLV) is an emerging virus that causes syncytial hepatitis of tilapia with mortalities of up to 90%. Recent disease outbreaks in Thai tilapia farms have been associated with high cumulative mortalities and histopathological features typical of SHT. Infection has now been confirmed. The semi-nested RT-PCR protocol described here may be used freely for non-commercial applications to detect TiLV. The authors urge laboratories in Asia to test for TiLV when abnormal tilapia mortality occurs.

A new and improved PCR detection method for Enterocytozoon hepatopenaei (EHP) based on a gene encoding a spore wall protein

Hepatopancreatic microsporidiosis (HPM) caused by Enterocytozoon hepatopenaei (EHP) is a newly emerging disease of cultivated shrimp in Asia. Current evidence indicates that it can be associated with severe growth retardation that may not be clearly evident until the second month of culture and may cause low continuous mortality in the case of very severe infections. We present a new method for detecting EHP that has superior specificity to the first generation SSU-PCR developed in 2009.

Hepatopancreatic microsporidiosis caused by Enterocytozoon hepatopenaei: Disease card

This disease card describes the diagnosis and range of a microsporidian shrimp pathogen, Enterocytozoon hepatopenaei (EHP), first discovered in Penaeus monodon in Thailand in 2004. It infects only the tubule epithelial cells of the hepatopancreatic tissue of shrimp. EHP was later found to also infect P. vannamei cultivated in Thailand and is suspected to have been reported from P. japonicus in Australia in 2001. EHP has been reported from Vietnam and is associated with white faeces syndrome.

A two-tube, nested PCR detection method for AHPND bacteria

A new method for the detection of AHPND-bacteria (AP4) has been published and is available for download. The advantage of the AP4 method over the previously published AP3 method is that it has 100 times higher sensitivity. Because of its higher sensitivity, the bacterial culture enrichment step needed when using the AP3 with low levels of AHPND bacteria may be omitted. However, the AP4 method should not be considered as a replacement for AP3.

Acute Hepatopancreatic Necrosis Disease Card (updated June 2014)

Acute hepatopancreatic necrosis disease (AHPND) has recently been found to be caused by a pathogenic strain of Vibrio parahaemolyticus. This updated disease card provides a summary and guidance on disease signs at the pond level, at the animal level by histopathology, molecular diagnostic tools, host range, presence in Asia-Pacific, prevention and control and links to further information.

Acute Hepatopancreatic Necrosis Syndrome (AHPNS): Status Update

Since the Asia Pacific Emergency Regional Consultation on EMS/AHPNS held in August 2012 in Bangkok, Thailand, many news reports have been widely circulated that have led to various baseless speculations and conclusions on the true nature of AHPNS. This disease update/advisory has been issued to address the many circulating false and baseless speculations on the effects and spread of AHPNS in the region.

Acute hepatopancreatic necrosis disease card

In the absence of identified biotic or abiotic cause(s) of the syndrome, this disease card provides information on signs that can be used for presumptive (pond level) and confirmative (animal level) diagnosis of acute hepatopancreatic necrosis syndrome of shrimp. The syndrome involves mass mortalities of up to 100% during the first 20-30 days after stocking. Affected shrimp consistently show an abnormal hepatopancreas, which may be shrunken, swollen or discoloured; loose shells, corkscrew swimming, pale colouration and slow growth.

Disease advisory: Infectious myonecrosis

Infectious myonecrosis is a viral disease caused by infectious myonecrosis virus. It affects Pacific white shrimp Penaeus vannamei, tiger shrimp P. monodon and blue shrimp P. stylirostris. IMN is associated with heavy losses in farmed shrimp of 40-70%. Originally reported from Brazil, outbreaks were first reported in Indonesia in May 2006. With the current spread of the disease there is a high threat of the disease spreading to neighbouring P. vannamei-producing countries.

Acute viral necrosis in scallops: Disease card

Acute viral necrosis in scallops was included in the list of Qquarterly Aquatic Animal Disease (QAAD) reporting list for the year 2008. The disease card developed by regional resource experts from China in support of QAAD reporting system in Asia-Pacific provides information on pathogen, hosts, and confirmatory diagnostic methods. This is an emerging disease in the region and has caused significant losses to scallop culture industry in China.