The susceptibility of the endemic copepod Calanus pacificus californicus to white spot syndrome virus (WSSV) was established by the temporal analysis of WSSV VP28 transcripts by quantitative real-time PCR (qRT-PCR). The copepods were collected from a shrimp pond located in Bahia de Kino Sonora, Mexico, and challenged per os with WSSV by a virus-phytoplankton adhesion route. Samples were collected at 0, 24, 48 and 84 h postinoculation (hpi). The VP28 transcripts were not detected at early stages (0 and 24 hpi); however, some transcript accumulation was observed at 48 hpi and gradually increased until 84 hpi. Thus, these results clearly show that the copepod C. pacificus californicus is susceptible to WSSV infection and that it may be a potential vector for the dispersal of WSSV. However, further studies are still needed to correlate the epidemiological outbreaks of WSSV with the presence of copepods in shrimp ponds.

No abstract

No abstract

At present, the Pacific oyster Crassostrea gigas is the most cultivated shellfish in northwest Mexico. Nonetheless, other mollusks species such as the black clam Chione fluctifraga, which can be found along with cultured C. gigas in Sonora, represents a profitable emerging fishery resource. Since 1997, the oyster industry along the Gulf of California has been affected by severe mortality episodes disturbing almost all the farming areas. In order to evaluate the prevalence of Perkinsus marinus, a monthly sampling of 30 oysters and 30 clams was carried out during a one-year period. A total of 360 oysters and 360 clams were analyzed by Ray's fluid thyoglicolate medium (RFTM) and PCR. The RFTM assay showed prevalence ranging from 3.3 to 60% for both oysters and clams through the study period, with infection levels from light to moderate, according to the Mackin scale. The PCR analysis was positive to P. marinus in the only one C. gigas with moderate infection in the RFTM analysis. The resulting sequence revealed 100% identity with the ITS region of P. marinus. To our knowledge, this is the first indication of Perkinsus sp. in the C. fluctifraga clam.

No abstract

No abstract

Beyond their ability to infect and spread, viruses lack the ability to replicate by their own. To counter this, viruses have evolved strategies to exploit the host's machinery for the production of new virions. However, viruses are by no means merely passive consumers of host metabolic products. Viruses induce remarkable changes in their host's cellular metabolism, yielding a metabolic state, to meet its specific requirements. The decapod penstyldensovirus (PstDV‐1) is probably the most prevalent virus affecting shrimp farming and has been associated with massive mortality outbreaks in hatchery‐reared larvae and juveniles of Penaeus stylirostris, and results in developmental deformities in symptomatic specimens of P. vannamei. Previous studies have suggested that PstDV‐1 induces metabolic reprogramming of P. vannamei to achieve a successful replication. In this study, the effects of PstDV‐1 infection over the gene expression of pyruvate kinase and pancreatic lipase of the shrimp P. vannamei were evaluated. The expression of both genes was significantly altered by PstDV‐1 infection, which may lead to the accumulation of specific metabolites, as lactate and fatty acids, providing a suitable platform for viral assembly and replication. The transcriptional profile of pyruvate kinase and pancreatic lipase‐encoding mRNAs offers initial clues on the potential metabolic alteration that contribute to PstDV‐1 pathogenesis.

The search for exotic pathogens related to the outbreaks and in surveillance samplings of the Mexican oyster farms, is a recent activity achieved by academic institutions and state committees for Aquatic Animal Health, with remarkable results. In samples of Crassostrea gigas collected through December 2009, January 2010 and November 2010, and of C. corteziensis in September 2011, the protozoan Marteilia refringens was detected for the first time in the Gulf of California. The carrier oysters were from cultures without abnormal mortality rates, whereby, the use of histology, in situ hybridization and transmission electron microscopy studies are necessary to determine if M. refringens has become established in the Gulf of California oyster cultures. Detection of M. refringens is of great concern to the global oyster farming industry.