Prevalence Of Perkinsus Research Articles

Survey on Perkinsus species in two economic mussels (Mytilus coruscus and M. galloprovincialis) along the coast of the East China Sea and the Yellow Sea.

Perkinsus, a parasitic pathogen of marine bivalves, is widely distributed among various mollusks in numerous countries. However, the prevalence and diversity of Perkinsus species in the two economically important mussels, Mytilus coruscus and M. galloprovincialis, in China remain unknown. The presence of the Perkinsus species was identified in the two mussels sampled along the coast of the East China Sea and the Yellow Sea, using both the alternative Ray's fluid thioglycolate medium (ARFTM) and conventional polymerase chain reaction (PCR). The ARFTM test indicated the presence of Perkinsus-like hypnospores in the two mussels. The diameter of the hypnospores in M. coruscus was significantly smaller than that in M. galloprovincialis. The prevalence of Perkinsus in M. galloprovincialis and M. coruscus ranged from 0 to 37.5% and 0 to 25%, respectively. The mean intensity of Perkinsus in M. galloprovincialis and M. coruscus ranged from 0 to 5.14 and 0 to 4.92, respectively. The PCR assay showed that the prevalence of Perkinsus spp. in M. galloprovincialis and M. coruscus was 0 to 25.0% and 0 to 12.5%, respectively. The homology analysis of the newly obtained internal transcribed spacer (ITS) sequences of Perkinsus revealed the highest identity of 100% with P. beihaiensis. The phylogenetic analysis indicated that the Perkinsus isolates from the two mussels were clustered with P. beihaiensis. The results of the molecular biology indicated that only P. beihaiensis was detected in the two mussels. The highest prevalence of P. beihaiensis was observed in Liaoning province (Dalian, 20.83%), followed by Shandong province, Zhejiang province and Fujian province. Consequently, it is recommended that surveillance should be conducted in Dalian, where the prevalence and mean intensity of P. beihaiensis in M. galloprovincialis are the highest.

Prevalencia de Perkinsus sp. (Apicomplexa) en la almeja chocolata Megapitaria squalida de la costa central de Sinaloa, México

Background. Different species of Perkinsus spp. have been associated to mortality of commercial mollusks. Goals. The prevalence of Perkinsus sp. in the callista clam Megapitaria squalida was evaluated monthly (June 2015 to November 2016) to determine the relationship between the infection and size of clam. Methods. 5,000 clam seeds (5.73 mm height of the shell and 0.03 g of initial weight) were placed in a fishing refuge of Altata, Sinaloa. A total of 60 specimens were collected each month to evaluate their growth and parasite prevalence. The water physicochemical parameters (temperature, salinity, pH, dissolved oxygen, depth, and transparency) and the length, height, and width of the shell and final weight of M. squalida were obtained. Results. Ray’s thioglycollate fluid medium test (MFTR) detected spherical cells (10X) of dark color indicating the presence of presumed hypnospores of Perkinsus sp. during the first 17 months of sampling. The mean infection intensity was grade 2 (mild), while the maximum prevalence was 43.33% in the months of November (2015) and March (2016), with an average of 21.05%. None of the Perkinsus sp sample (n = 112) positively detected by MFTR confirmed the presence of the protozoan. There was no correlation (p >0.05) between the prevalence of the pathogen with all the parameters studied. Conclusions. The results suggest that M. squalida is not susceptible to Perkinsus sp. The present represents the first report of Perkinsus sp. In the callista clam M. squalida.

Seasonal occurrence of Perkinsus spp. and tissue distribution of P. olseni in clam (Soletellina acuta) from coastal waters of Wuchuan County, southern China

Seasonal occurrence of Perkinsus spp. infection in the wild clam, Soletellina acuta, along the coast of Wuchuan County, southern China was investigated over one year using conventional polymerase chain reaction (PCR) method combined with sequencing technique. The tissue distribution of P. olseni in (S. acuta) was also compared among four tissues, namely the gill, mantle, digestive gland, and siphon, using the real-time PCR method. S. acuta populations were concurrently infected by two Perkinsus spp., P. olseni and P. beihaiensis, among different sampling months. Prevalence of Perkinsus spp. infection in the clam ranges from 9.4% to 50.6% and is significantly different among seasons, and was significantly higher in the March sampling period (spring), while it was significantly lower in the June sampling period (summer). Different seasonal patterns of prevalence occur between P. olseni and P. beihaiensis infection in the clam (S. acuta). S. acuta is more prone to be infected by P. olseni than by P. beihaiensis. The results of qPCR assay demonstrated that positive rate of P. olseni in S. acuta differs significantly among the four tissues. P. olseni infected the gill and mantle tissues more preferably than the siphon tissue; however, the concentration of the parasite did not differ significantly among the four tissues.

First report of Perkinsus beihaiensis in wild clams Anomalocardia brasiliana (Bivalvia: Veneridae) in Brazil

This is the first report of Perkinsus sp. (Bivalvia: Veneridae) infecting wild clams of the species Anomalocardia brasiliana in Brazil. The gill lamellae and rectum of 150 specimens of A. brasiliana collected in the Timonha river estuary (Ceará, Northeastern Brazil) in March 2012 were incubated in Ray’s fluid thioglycollate medium (RFTM) for detection of Perkinsus sp. In RFTM, the prevalence of Perkinsus sp. was 14.7% (22/150) and the intensity of infection ranged from very light (1–10 cells across the slide) to light (12–100 cells). The presence of Perkinsus sp. was confirmed by PCR in seven (31.8%) out of 22 RFTM-positive specimens. DNA sequencing confirmed the presence of the genus Perkinsus and the phylogenetic analysis strongly indicated Perkinsus beihaiensis as the species responsible for the infection.

Infection prevalence and phylogenetic analysis of Perkinsus olseni in Ruditapes philippinarum from East China

The prevalence of Perkinsus sp. infection in Manila clam Ruditapes philippinarum was investigated in the coastal areas of east China. Thirteen groups of clams were collected from 5 sites: Dandong and Qingdao Bays (Yellow Sea), Weifang Bay (Bohai Sea), and Ningbo and Fuzhou Bays (East China Sea). The clams were tested for perkinsosis infection using Ray's fluid thioglycollate medium culture assay. Perkinsus sp. was found in samples from all 5 sites from May 2008 to May 2009. Infection prevalence ranged from 43.75 to 95.83%, and was significantly higher in October than in May. The only 3 uninfected groups of clams were collected from Weifang Bay, the site farthest from the ocean. There was no difference in the prevalence of infection among the remaining 4 sites. The conserved internal transcribed spacer regions of the ribosomal RNA gene complex in each of the Perkinsus sp. isolates were amplified by PCR. The resulting amplicons were sequenced and phylogenetically analyzed. All the Perkinsus isolates were identified as Perkinsus olseni.

Monitoring of infections by protozoa of the genera Nematopsis, Perkinsus and Porospora in the smooth venus clam Callista chione from the North-Western Adriatic Sea (Italy).

Marketable smooth venus clams Callista chione from natural banks of Chioggia (Venice) and Goro (Ferrara), North-Western Adriatic Sea (Italy), were examined for protozoan parasites from November 1996 to November 1998. Out of the 375 bivalves examined, 149 (39.7%) were infected by Nematopsis sp. and 325 (86.7%) by Porospora sp. Oocysts of Nematopsis sp. were present with a prevalence that varied from 100% in November 1996 to 5% in June 1998; cystic and naked sporozoites of Porospora sp. were very common, with a prevalence of 100%. Out of the 229 bivalves examined between January and November 1998, 63 (27.5%) were also infected by Perkinsus sp.; the prevalence of Perkinsus sp. varied from 9.1% in January to 50% in February. To our knowledge this is the first report of Porospora sp. and Perkinsus sp. in C. chione.