Biomedical subjects

Joyce J Evans

Publications and source records attributed to Joyce J Evans.

8 recordsLinked to original sources

PubMed2006

Immunization of eyed channel catfish, Ictalurus punctatus, eggs with monovalent Flavobacterium columnare vaccine and bivalent F. columnare and Edwardsiella ictaluri vaccine.

The efficacy of a modified live monovalent Flavobacterium columnare vaccine and bivalent F. columnare and Edwardsiella ictaluri vaccines were evaluated following immersion vaccination of eyed channel catfish (Ictalurus punctatus) eggs. The modified live F. columnare vaccine was grown in modified Shieh broth and administered at 1.35 x 10(7) CFU/ml for 15 min exposure (1l water). Booster immunization was conducted at day 34 with 2.17 x 10(7) CFU/ml for 15 min. Bivalent vaccines consisted of a 1:1 ratio of the modified live F. columnare and AQUAVAC-ESC vaccine for the 15 min exposure (1l immersion bath). Non-vaccinated controls were held in 1l water without vaccine for 15 min. Fish were challenged with F. columnare (ALG-00-530) by immersion at days 109, 116, and 137 post-primary immunization or E. ictaluri (AL-93-75) by immersion at day 116 (bivalent vaccine group). Efficacy of monovalent modified live F. columnare vaccine administered singly or with a booster vaccination was shown to be protective with relative percent survival (RPS) values ranging from 50.0 to 76.8. Some variation was seen in RPS values following bivalent immunization, ranging from 33.0 to 59.7 in the fish challenged with F. columnare and 44.5 to 66.7 in fish challenged with E. ictaluri. However, the RPS values were not statistically different. The results suggest that administration of live bivalent vaccine at the eyed-egg stage is safe and elicits protection upon single pathogen challenge.

Animals↗

PubMed2006

The macrophage chemotactic activity of Streptococcus agalactiae and Streptococcus iniae extracellular products (ECP).

The ability of Streptococcus agalactiae and Streptococcus iniae to attract macrophages of Nile tilapia (Oreochromis niloticus) was investigated. The extracellular products (ECP) from S. agalactiae and S. iniae were tested in vitro for macrophage chemotaxis using blind-well chambers. The macrophages were obtained from the peritoneal cavity 4-5 days after intraperitoneal injection of squalene. Both macrophage chemotactic and chemokinetic activities were demonstrated using the S. agalactiae ECP. However, only chemotactic activity was shown for S. iniae ECP. High-pressure liquid chromatography fractionation revealed that semi-purified S. agalactiae and S. iniae ECPs had estimated molecular weights of 7.54 and 19.2kDa, respectively. The prominent chemotactic activities of ECP from S. agalactiae and S. iniae are likely to be involved in the proinflammatory responses of macrophages to S. agalactiae and S. iniae infections.

Animals↗

PubMed2006

Passive immunization of Nile tilapia (Oreochromis niloticus) provides significant protection against Streptococcus agalactiae.

A study was conducted to determine the role of specific antibodies in immunity to Streptococcus agalactiae. Adult Nile tilapia (Oreochromis niloticus) were injected i.p. with tryptic soy broth as control or with S. agalactiae vaccine. Ninety days later, fish were challenged with 1.5x10(4)CFUS. agalactiae fish(-1). Blood was drawn from all fish 90d after vaccination and 25d after challenge, and the acquired serum was injected i.p. in fingerling Nile tilapia. These passively immunized fish were subsequently challenged 72h later with 1.5x10(4)CFUS. agalactiae fish(-1), and significantly less (P<0.0001) mortalities were noted among fish administered serum containing specific anti-S. agalactiae antibodies (0.0-10.0% mortalities) than in control groups (63.3-72.7% mortalities). Heat-inactivation of serum produced no significant differences in mortalities than non-heat-treated serum in groups administered serum containing specific antibodies from vaccinated fish (P<0.9455) or vaccinated-challenged fish (P<0.0781). Pre-challenge serum samples indicate that the passively immunized fish had significantly increased (P<0.0001) specific antibody levels over control fish. A highly significant (r(2)=0.5892; P<0.0001) correlation between increased pre-challenge specific serum antibody OD levels and survival after challenge was demonstrated when analyzing the control and passive immunization groups. The results of this study indicate that specific anti-S. agalactiae antibodies play a primary role in immunity to S. agalactiae in fish.

Animals↗

PubMed2006

A vaccination and challenge model using calcein marked fish.

A vaccination and challenge cohabitation model was established and evaluated using Nile tilapia (Oreochromis niloticus), the fluorescent chromophore calcein, and a Streptococcus iniae vaccine. Tilapia were non-invasively calcein marked, sham-vaccinated (CMSV) and cohabited with non-marked sham-vaccinated (NMSV) or non-marked S. iniae vaccinates (NMV) as a single unit. After 30 d, the cohabitants were challenged with a virulent isolate of S. iniae by intraperitoneal (ip) injection and the cumulative mortality was measured over a period of 15 d. Calcein marking did not have a significant effect on S. iniae susceptibility as mortality of CMSV and NMSV was not significantly different (P=0.6756). Nor did calcein marking have an effect on the vaccination and challenge cohabitation model. The results showed that the cumulative mortality of CMSV (N=160) was significantly greater (P<0.0003) than those of NMV (N=160). The results of the calcein marking trials indicate that the most suitable calcein concentration and exposure time to produce detectable fluorescent marking of tilapia was 500 mg L(-1) for 4 h. Furthermore, the calcein marks were readily visible in the calcified skeletal structures of head and fins using a portable handheld UV lamp set at 365 nm wavelength. Calcein appears to be a valuable tool for non-invasive, non-lethal, non-stressful, mass marking of fish to differentiate between sham- and pathogen-vaccinated fish in this cohabitation model. The vaccination and challenge cohabitation model also offers the statistical advantage of using individual fish as the experimental unit maintained in the same aquarium.

Animals↗

PubMed2006

First report of Streptococcus agalactiae and Lactococcus garvieae from a wild bottlenose dolphin (Tursiops truncatus).

The isolation and characterization of two bacterial species, Streptococcus agalactiae and Lactococcus garvieae, previously unreported in wild marine mammals are described from a freshly dead bottlenose dolphin, Tursiops truncatus, from Kuwait Bay, Kuwait, in September 2001. Conventional and rapid identification systems were used to determine that isolates from muscle and kidney were S. agalactiae and L. garvieae, respectively. The isolates were gram-positive, catalase-negative, oxidase-negative, nonhemolytic cocci. The S. agalactiae was serotyped to group antigen B, whereas the L. garvieae could not be assigned to any serogroup. These Kuwait isolates displayed considerable homogeneity with corresponding American Type Culture Collection (ATCC) type isolates. Although the dolphin S. agalactiae isolate was nonhemolytic, it was biochemically similar to S. agalactiae isolated from mullet sampled in the concurrent Kuwait Bay fish kill. Some biochemical heterogeneity was observed between the dolphin isolates and corresponding mammalian ATCC type isolates, especially with Voges Proskauer, alanine-phenylanaline-proline arylamidase, and alpha-galactosidase tests. Nile tilapia, Oreochromis niloticus, experimentally infected with the dolphin S. agalactiae and L. garvieae isolates experienced 90% and 0% mortalities, respectively. This is the first isolation of S. agalactiae and L. garvieae from a wild marine mammal, and the microbial characteristics established here provide pertinent information for the future isolation of these bacteria.

Animals↗

PubMed2005

Duration of protective antibodies and correlation with survival in Nile tilapia Oreochromis niloticus following Streptococcus agalactiae vaccination.

Streptococcus agalactiae is a major piscine pathogen that causes significant morbidity and mortality among numerous species of freshwater, estuarine and marine fishes. Considering the economic importance of fishes susceptible to S. agalactiae throughout the world, an efficacious S. agalactiae vaccine was developed using an extracellular product (ECP) fraction and formalin-killed whole cells of S. agalactiae. A vaccine study was conducted by intraperitoneal (i.p.) injection in Nile tilapia Oreochromis niloticus in order to determine the duration of protection and its correlation to antibodies specific for this pathogen. After 47, 90 or 180 d post-vaccination (DPV), the fish were i.p. challenged with approximately 2.0 x 10(4) S. agalactiae colony-forming units (CFU) fish(-1) to determine the duration of protective immunity. The percent survival in control fish i.p.-injected with sterile TSB was 16,16, and 4% on 47, 90 and 180 DPV, respectively, while the percent survival for the vaccinated fish was 67, 62 and 49%, respectively. The specific mean antibody concentration of the vaccinated fish was significantly higher than that of the control fish, with significant correlation between the ELISA optical density (OD) and protection. These results indicate that the specific antibody has a correlation with protection following immunization with the S. agalactiae vaccine and that the vaccine can confer protection against S. agalactiae up to 180 DPV.

Animals↗

PubMed2004

Efficacy of Streptococcus agalactiae (group B) vaccine in tilapia (Oreochromis niloticus) by intraperitoneal and bath immersion administration.

We evaluated the effectiveness of a Streptococcus agalactiae vaccine in tilapia (Oreochromis niloticus) for prevention of streptococcal disease. The vaccine was prepared from formalin-killed cells and concentrated extracellular products (greater than 3 kDa) of a single isolate of S. agalactiae (ARS-KU-MU-11B). Intraperitoneal (IP) and bath immersion (BI) vaccine trials were conducted at two temperatures, 32 and 26 degrees C, and mean fish weights, 5 and 30 g. Control tilapia were injected with tryptic soy broth. Thirty gram tilapia vaccinated and challenged by IP injection with 1.5 x 10(4) colony-forming units (CFU)/fish of Streptococcus agalactiae at 30 days post-immunization had a relative percent survival (RPS) of 80. Smaller tilapia vaccinated and challenged under similar conditions had an RPS of 25. An RPS of zero was noted in 30 g fish IP vaccinated with Streptococcus iniae and IP challenged with S. agalactiae. The 5 and 30 g tilapia bath immunized with S. agalactiae and IP challenged with 3.6 x 10(5) and 1.7 x 10(6) CFU/fish of S. agalactiae had RPS values of 34. Intraperitoneal administration of the vaccine provided efficacious protection only in the 30 g tilapia regardless of whether the fish were immunized and challenged at 26 or 32 degrees C. Bath immunization of both 5 and 30 g tilapia resulted in RPS values that were two times lower than those achieved with IP vaccination. The results of this study suggest that there is a lack of cross-protection of S. iniae bacterins against S. agalactiae challenge. Protection against S. agalactiae infection is, however, provided through vaccination with a S. agalactiae modified bacterin vaccine.

Animals↗

PubMed2004

Warmwater fish vaccinology in catfish production.

The ability of the fish industry to provide a continuous supply of fish protein depends on both proper biosecurity and strategies to significantly reduce the risk of infectious diseases. Vaccination is a safe and effective means to prevent disease and to increase the productivity and profitability of farmed fish. Vaccines are likely to be the prime prophylactic measure of the future because of rapidly developing advances in fish vaccine technology and producer acceptance. The efficacy of a vaccine is influenced by a variety of factors that must be considered in the development of vaccination strategies for fish. This review highlights some of these factors. The response to a modified live vaccine against Edwardsiella ictaluri is used for illustration.

Animals↗