Detection of a new microsporidium Perezia sp. in shrimps Penaeus monodon and P. indicus by histopathology, in situ hybridization and PCR.

Samples of microsporidia-infected shrimps exhibiting clinical signs of cotton shrimp disease were collected from Madagascar, Mozambique, and the Kingdom of Saudi Arabia from 2005 to 2014. The tails of the infected shrimps appeared opaque and whitish; subsequent histological examination revealed the presence of cytoplasmic inclusions and mature spores in tissues of the muscle, hepatopancreas, gills, heart, and lymphoid organ. PCR analysis targeting the small subunit rDNA (SSU rDNA) from infected samples resulted in the amplification of a 1.

Development of in situ hybridization and PCR assays for the detection of Enterocytozoon hepatopenaei (EHP), a microsporidian parasite infecting penaeid shrimp.

A microsporidian parasite, Enterocytozoon hepatopenaei (abbreviated as EHP), is an emerging pathogen for penaeid shrimp. EHP has been found in several shrimp farming countries in Asia including Vietnam, Thailand, Malaysia, Indonesia and China, and is reported to be associated with growth retardation in farmed shrimp. We examined the histological features from infected shrimp collected from Vietnam and Brunei, these include the presence of basophilic inclusions in the hepatopancreas tubule epithelial cells, in which EHP is found at various developmental stages, ranging from plasmodia to mature spores.

Determination of the infectious nature of the agent of acute hepatopancreatic necrosis syndrome affecting penaeid shrimp.

A new emerging disease in shrimp, first reported in 2009, was initially named early mortality syndrome (EMS). In 2011, a more descriptive name for the acute phase of the disease was proposed as acute hepatopancreatic necrosis syndrome (AHPNS). Affecting both Pacific white shrimp Penaeus vannamei and black tiger shrimp P.

A histological variant of white spot syndrome virus (WSSV) from the Kingdom of Saudi Arabia.

White spot syndrome virus (WSSV) is highly pathogenic to penaeid shrimp. The major targets of WSSV infection are tissues of ectodermal and mesodermal embryonic origin, predominantly the cuticular epithelium and subcuticular connective tissues. Recently, we discovered a WSSV variant in Penaeus indicus that heavily infects the subcuticular connective tissue, with very slight indications in the cuticular epithelium.

"Candidatus Hepatobacter penaei," an intracellular pathogenic enteric bacterium in the hepatopancreas of the marine shrimp Penaeus vannamei (Crustacea: Decapoda).

The bacteria that cause necrotizing hepatopancreatitis in Penaeus vannamei adversely affect penaeid shrimp cultured in the western hemisphere. 16S rRNA and gyrase B gene analyses determined the taxonomic position of these bacteria. The name "Candidatus Hepatobacter penaei" is proposed for these pathogenic bacteria, which are members of the Rickettsiales order.

New genotypes of white spot syndrome virus (WSSV) and Taura syndrome virus (TSV) from the Kingdom of Saudi Arabia.

White spot syndrome virus (WSSV) and Taura syndrome virus (TSV) are highly pathogenic to penaeid shrimp and have caused significant economic losses in the shrimp culture industry around the world. During 2010 and 2011, both WSSV and TSV were found in Saudi Arabia, where they caused severe mortalities in cultured Indian white shrimp Penaeus indicus. Most outbreaks of shrimp viruses in production facilities can be traced to the importation of infected stocks or commodity shrimp.

Histopathological characterization and in situ detection of Callinectes sapidus reovirus.

A reovirus (tentatively designated as Callinectes sapidus reovirus, CsRV) was found in the blue crabs C. sapidus collected in Chesapeake Bay in 2005. Histological examination of hepatopancreas and gill from infected crabs revealed eosinophilic to basophilic, cytoplasmic, inclusions in hemocytes and in cells of connective tissue.

Ultrastructural and sequence characterization of Penaeus vannamei nodavirus (PvNV) from Belize.

The Penaeus vannamei nodavirus (PvNV), which causes muscle necrosis in Penaeus vannamei from Belize, was identified in 2005. Infected shrimp show clinical signs of white, opaque lesions in the tail muscle. Under transmission electron microscopy, the infected cells exhibit increases in various organelles, including mitochondria, Golgi stacks, and rough endoplasmic reticulum.

Case reports of melamine-induced pathology in penaeid shrimp fed adulterated feeds.

Shrimp (Penaeus monodon and P. vannamei) specimens were submitted to the University of Arizona's Aquaculture Pathology Laboratory (UAZAPL) and to the Texas Veterinary Medical Diagnostic Laboratory (TVMDL) in 2007 and 2008 from shrimp-rearing facilities in India and Indonesia for histological testing. These were found to present prominent golden to greenish-brown needle- and plate-like birefringent crystals within multifocal hemocytic granulomas in the antennal gland tubules and peritubular hemal sinuses.

Nucleotide sequence of a Madagascar hepatopancreatic parvovirus (HPV) and comparison of genetic variation among geographic isolates.

A segment of Madagascar hepatopancreatic parvovirus (HPV) genomic sequence (5742 nucleotides) was determined through PCR and direct sequencing. This nucleotide sequence was compared to isolates from Australia, Thailand, Korea, and Tanzania, and the mean distance was determined to be 17%. The Madagascar HPV is closest to the Tanzania isolate (12%), followed by isolates from Korea (15%), Australia (17%) and Thailand (20%).

Development of in situ hybridization and RT-PCR assay for the detection of a nodavirus (PvNV) that causes muscle necrosis in Penaeus vannamei.

A nodavirus (tentatively named PvNV, Penaeus vannamei nodavirus) that causes muscle necrosis in P. vannamei was found in Belize in 2004. From 2004 to 2006, shrimp samples collected from Belize exhibited clinical signs, white, opaque lesions in the tails and histopathology similar to those of shrimps infected by infectious myonecrosis virus (IMNV).

Identification of an iridovirus in Acetes erythraeus (Sergestidae) and the development of in situ hybridization and PCR method for its detection.

An iridovirus (tentatively named SIV, sergestid iridovirus) that causes high mortality in the sergestid shrimp, Acetes erythraeus, was found in Madagascar in 2004. Severely affected shrimp exhibit a blue-green opalescence. Histological examination revealed massive cytoplasmic inclusions in the cuticular epithelial cells, connective tissues, ovary and testes.

Characterization of a rediscovered haplosporidian parasite from cultured Penaeus vannamei.

Mortalities of Penaeus vannamei, cultured in ponds in Belize, Central America, began during the last part of the grow-out cycle during the cold weather months from September 2004 through February 2005. Tissue squashes of infected hepatopancreata and histological examination of infected shrimp revealed that the mortalities might have been caused by an endoparasite. To confirm the diagnosis, DNA was extracted from ethanol preserved hepatopancreata and the small-subunit rRNA gene was sequenced.

Ultrastructure of the replication site in Taura syndrome virus (TSV)-infected cells.

Taura syndrome virus (TSV) is a member of the family Dicistroviridae that infects Pacific white shrimp Litopenaeus vannamei (also called Penaeus vannamei), and its replication strategy is largely unknown. To identify the viral replication site within infected shrimp cells, the viral RNA was located in correlation with virus-induced membrane rearrangement. Ultrastructural changes in the infected cells, analyzed by transmission electron microscopy (TEM), included the induction and proliferation of intracellular vesicle-like membranes, while the intracytoplasmic inclusion bodies and pyknotic nuclei indicative of TSV infection were frequently seen.

Purification and characterization of infectious myonecrosis virus of penaeid shrimp.

The causative agent of myonecrosis affecting cultured Penaeus vannamei in Brazil was demonstrated to be a virus after purification of the agent from infected shrimp tissues. Purified viral particles were injected into specific pathogen-free P. vannamei, resulting in a disease that displayed the same characteristics as those found in the original shrimp used for purification.

In situ hybridization demonstrates that Litopenaeus vannamei, L. stylirostris and Penaeus monodon are susceptible to experimental infection with infectious myonecrosis virus (IMNV).

Infectious myonecrosis virus (IMNV) was recently found to be the cause of necrosis in the skeletal muscle of farm-reared Litopenaeus vannamei from northeastern Brazil. Nucleic acid extracted from semi-purified IMN virions showed that this virus contains a 7.5 kb RNA genome.

Characterization and molecular methods for detection of a novel spiroplasma pathogenic to Penaeus vannamei.

Traditionally, Spiroplasma spp. have only been isolated from the surfaces of flowers and other plant parts, from the guts and hemolymph of various insects, and from vascular plant fluids (phloem sap) and insects that feed on these fluids. In this article, we report the first pathogenic spiroplasma to be discovered in shrimp and the results of its characterization through histological evaluation, in situ hybridization assays, transmission electron microscopy, 16S rRNA sequence homology, and injection infectivity studies.

Nonsusceptibility of primate cells to Taura syndrome virus.

Taura syndrome virus (TSV), a pathogen of penaeid shrimp and member of the family Dicistroviridae, was recently reported to have the ability to infect primate cells. We independently retested this hypothesis. Three lines of primate cells FRhK-4, MA-104, and BGMK, which are highly susceptible to infection by human picornaviruses, were challenged with TSV.