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1.
K Urquhart T J Bowden B-E Buckett J Garcia R J Fryer A E Ellis 《Journal of fish diseases》2009,32(5):447-456
Intraperitoneal (IP) injection, cohabitation and immersion routes of infection were used to determine if Atlantic cod, Gadus morhua (L.), of 1 and 3 g are susceptible to infectious pancreatic necrosis (IPN). Mortalities of cod injected IP were significantly higher when challenged with infectious pancreatic necrosis virus (IPNV) than with phosphate buffered saline. This is the first report of Atlantic cod mortalities caused by IPNV. Fish challenged by cohabitation had significantly higher mortalities than the controls, but mortalities of Atlantic cod challenged with IPNV by immersion were not significantly different from controls. Titres of IPNV in the tissues of infected fish were sometimes very high (range 102 –1010 infectious units per gram of tissue) suggesting virus replication and titres of fish that died were generally higher than those of fish which survived. However, the relatively low mortality rates when challenged by cohabitation and immersion (20% and 17%, respectively), compared to the IP injection challenge (100%) suggest that 1 and 3 g cod have low susceptibility to IPN when challenged by more natural routes. These data strongly suggest that the cause of death of experimentally challenged cod was IPNV and further histological evidence for this came from 1 g cod challenged IP with IPNV in which the pancreas showed severe necrosis and heavy immunostaining for IPNV coincidentally with the peak of mortalities. 相似文献
2.
Abstract. A bacterin for immunization against bacterial kidney disease of salmonid fishes caused by Renibacterium salmoninarum is described. Cultures were grown in Evelyn's KDM2 medium containing 10% calf serum in a fermenter under the following conditions: pH 7.2, 15°C, 800ml/min air, 200 rev/min agitation and 5–15 days of incubation. Possible substitutes for calf serum were 10% horse serum 0.15% starch and leptospira medium. The bacterins were inactivated with 0.3% formalin and no adjuvants were used. Other tests evaluated pH-lysed bacterin, 50% concentrated bacterin and 50% concentrated pH-lysed bacterin. Juvenile rainbow trout, salmo gairdneri Richardson, were vaccinated either by intraperiotoneal (i.p.) injection, 2 min immersion or 2-step hyperosmotic infiltration. Fish were held from four to six weeks at 11°C, then challenged by i.p. injection with the homologous virulent bacterium. Fish died from days 19 to 40 after challenge. The best preparation was pH-lysed bacterin given by a single i.p. injection; hyperosmotic and immersion vaccination were not effective. Typically when 80% or more of unvaccinated controls were infected as detected by Gram stain, 10% or less of the vaccinated fish were infected. 相似文献
3.
Streptococcus iniae and Gyrodactylus niloticus are two common pathogens of cultured Nile tilapia, Oreochromis niloticus. We studied concurrent infection of tilapia by G. niloticus and S. iniae and evaluated whether parasitism in tilapia with Gyrodactylus increased susceptibility and mortality following immersion infection with S. iniae. Results showed that death mainly occurred in fish with G. niloticus and challenged with S. iniae (G-S group). The accumulative mortality (42.2%) was significantly higher in the G-S group than in fish not infected by the parasite (6.7%), but exposed to S. iniae. Bacteriological examination revealed S. iniae from > or =92% of dead or moribund fish challenged with S. iniae. Gyrodactylus not only damaged fish epithelium and provided entry for invasive bacteria but also was found to harbour viable cells of S. iniae for 24 and 72 h. Streptococcus iniae was isolated from 60% and 40% of G. niloticus collected from fish infected by intraperitoneal injection or immersion, respectively, at 24 h post-challenge. The present study confirms that parasitism of tilapia by G. niloticus increased host mortality following exposure to the bacterial pathogen S. iniae. 相似文献
4.
Branchial xenomas were detected by week 5 and disappeared by week 10 after naive juvenile rainbow trout, held at 14.5 °C, were fed or intubated with Loma salmonae ‐infected gill tissue preparations. Upon re‐challenge with L. salmonae , these fish were protected from disease and branchial xenomas did not develop. Branchial xenomas were never detected in naive fish held at 10 °C and exposed to L. salmonae . When these fish were re‐challenged with L. salmonae at 14.5 °C, they were also protected from the disease. Branchial xenomas also developed after naive fish, held at 14.5 °C, were injected intraperitoneally with a semipurified preparation of fresh spores, but generally did not develop after intraperitoneal injection with a preparation of spores subjected to freezing and thawing before use. Fish that had received fresh spores intraperitoneally were completely resistant to disease when re‐challenged via oral delivery of spores, whereas those that had received frozen spores were incompletely, but significantly, protected from disease compared with naive fish. We conclude that infection with L. salmonae induces strong protection towards the disease upon re‐exposure to spores, and that the protection does not depend on the completion of the parasite's life cycle, thus establishing the basis for further research on vaccine development for this disease. 相似文献
5.
甘草粗提物对鲫的抗应激及免疫保护功效研究 总被引：1，自引：0，他引：1
采用腹腔注射和混饲投喂两种方式研究中药甘草(Glycyrrhiza uralensis Fiseh)粗提物对鲫(Carassius auratus)的抗应激和免疫保护功效。将一部分粗提物按0.5%和2%的质量分数制成药饵投喂实验鲫,分别在第14 d、28 d、35 d、42 d、56 d采集血样;将另一部分粗提物用无菌生理盐水按0.5%和2%的浓度配成针剂腹腔注射鲫,分别在第3 d、7 d、14 d、21 d、28 d采集血样。结果显示:投喂实验中药物组和对照组血清皮质醇水平均呈先升后降趋势,除第14 d外,药物组皮质醇水平都低于同期对照组。在最后一次采样中(56 d),对照组、低剂量组和高剂量组的皮质醇水平分别为147.85 ng/mL、79.41 ng/mL和66.47 ng/mL。腹注实验中对照组皮质醇水平一直呈上升趋势,最后一次采样(28 d)高达274.23 ng/mL,显著高于药物组(P<0.01)。投喂甘草提取物56 d后,用Aeromonas hydrophila对鲫进行人工感染,低剂量组和高剂量组一周后的死亡率分别为45.0%和55.0%,显著低于对照组的70.0%(P<0.05)。腹注甘草提取物后第28 d,鲫受A.hydrophila菌人工感染,对照组、低剂量组和高剂量组的死亡率分别为60.0%、55.0%和35.0%,高剂量组显著低于对照组(P<0.05)。实验表明,投喂和腹注甘草粗提物后,可明显提高鲫的抗应激能力,并能增强鱼体对A.hydrophila的抵抗力。 相似文献
6.
The susceptibility of turbot, Psetta maxima, to infection with two strains of viral haemorrhagic septicaemia virus (VHSV) obtained from wild Greenland halibut, Reinhardtius hippoglossoides, and from farmed turbot was examined. A marine VHSV strain known to be highly pathogenic for turbot was also utilized for comparative purposes. Fish were infected by intra-peritoneal (i.p.), immersion or cohabitation, and maintained at two different temperatures (8 and 15 degrees C). Infection trials showed that the three VHSV isolates were pathogenic for turbot fingerlings by i.p. injection at both temperatures, with high levels of mortality. Virus was recovered from most pools of dead fish i.p. challenged, but not from surviving fish. Although clinical signs were not induced following waterborne exposure, viral growth was obtained from some pools of surviving fish challenged by immersion with strain GH40 from Greenland halibut, which indicates that the virus can survive in sea water and infect other fish via horizontal transmission. Furthermore, although low, the clinical signs and mortality observed in fish cohabitating with turbot challenged with strain GH40 confirms horizontal transmission and indicates that the passage through fish increases the virulence of this strain for turbot. These findings indicate that Greenland halibut, as other wild fish, may play an important role in the epizootiology of VHSV and suggest a potential risk for the turbot farming industry. 相似文献
7.
Passive immunization of rainbow trout, Oncorhynchus mykiss (Walbaum), was carried out to determine the persistence of anti-Streptococcus sp. antibodies (ASA) raised in sheep, rabbits or rainbow trout. The protection afforded by passive immunization was compared with the protection obtained from active immunization by immersion in or intraperitoneal (i.p.) injection with formalin-killed cells. Assessments were undertaken concurrently for up to 3 months post-immunization (PI) to evaluate the practical potential of passive immunization. Passively administered sheep and rabbit antibodies were detected in fish sera by enzyme-linked immunosorbcnt assay for more than 60 days after i.p. injection. Fish responded immunologically to these antibodies and the highest humoral responses to sheep and rabbit ASA occurred at 2 months PI. The relative per cent survival (RPS) of rainbow trout challenged with virulent Streptococcus sp. after an i.p. injection (0.1 ml 100 g?1 fish body weight) of sheep, rabbit or fish ASA was: 88.8, 50 and 0% after 1 month; 33.3, 6.8 and 6.8% after 2 months; and 13.3, 0 and 6.6% after 3 months PI, respectively. Fish immunized actively had an RPS of 88.8 and 11.1% after 1 month, 38.1 and 4.7% after 2 months, and 36 and 0% after 3 months PI for the i.p. injection and immersion routes, respectively. 相似文献
8.
Infections by the gill fluke Zeuxapta seriolae are a serious concern for sea cage aquaculture of kingfish, Seriola lalandi. The present study aimed to determine the pathophysiological effects of a progressive infection with Z. seriolae and the effects of treatment with hydrogen peroxide. For the progression of infection study, infected fish were taken from a sea cage farm, treated to remove parasites and then infected by cohabitation with heavily infected fish. Samples were taken at 2-week intervals for 8 weeks. Infection intensity peaked at 4 weeks post-infection (mean intensity 565.9) and the number of mature worms (2 mm fixed length or larger) peaked at 6 weeks post-infection. Attachment of Z. seriolae appeared to cause little localized pathology; however, the occurrence of hyperplastic lamellae increased as the infection progressed. Haemoglobin concentrations were negatively correlated with Z. seriolae intensity and were lower than controls at 4 weeks (35.8% decrease) and 6 weeks (57.4% decrease) post-infection. Blood lactate concentration and plasma osmolality increased throughout the course of infection. For the effect of treatment experiment, groups of infected and non-infected fish were sampled either before or after treatment with hydrogen peroxide. Treated fish from both infected and uninfected groups had increased plasma lactate, osmolality and pH compared with pre-treatment groups. Treatment with hydrogen peroxide appeared to have acute effects on fish health but the magnitude (e.g. lactate, osmolality) and extent of the effects (e.g. haemoglobin) was much less than that caused by chronic infection with Z. seriolae. 相似文献
9.
Vaccination strategies have traditionally been used as preventative or prophylactic measures against disease (prophylactic immunization) in uninfected fish. Alternatively, therapeutic or remedial measures, such as antibiotic administration, are commonly employed to treat disease in infected fish. Vaccination as a therapeutic measure (therapeutic immunization), however, has not been adequately explored in sub‐clinically infected fish. Therapeutic and prophylactic immunization with three Streptococcus iniae vaccines, formalin‐killed whole S. iniae cells (FKC vaccine), concentrated S. iniae extracellular products (greater than 2 kDa) (ECP vaccine) and a combination of killed cells and extracellular products (FKC+ECP vaccine), were tested in hybrid striped bass, Morone chrysops×Morone saxatilis, previously naturally infected with S. iniae. Fish (mean weight 10.0 g) were injected intraperitoneally (IP) or intramuscularly (IM) with one of each of the vaccines, tryptic soy broth (TSB‐control) or non‐injected (non‐injected control) to evaluate therapeutic effects (Trial 1). Survivors of the natural infection and ECP and FKC+ECP vaccine immunization and another lot of non‐injected control fish were immersion challenged with 1.47 × 106 CFU of S. iniae mL?1 at 44 days post‐immunization to evaluate vaccine efficacy (Trial 2). Hybrid striped bass (1.0 g) were also IM injected with S. iniae ECP vaccine at an aquaculture facility and immersion challenged with 1.47 × 106 CFU of S. iniae mL?1 12 weeks post‐immunization (Trial 3). The ECP and FKC+ECP vaccines, regardless of injection route, significantly (P<0.001) increased survival in asymptomatic, sub‐clinically infected fish thereby providing therapeutic merit. Hybrid bass immunized IP or IM had mean per cent survival values ranging from 78 to 96 at 44 days post‐immunization (Trial 1) and 69–97 post challenge (Trial 2). Survival of fish injected with TSB or immunized with FKC vaccine was significantly lowered and ranged from 12 to 13 by IP injection and 40 to 50 by IM injection and thus, the FKC vaccine had no therapeutic effect. The survival of hybrid striped bass IM immunized with S. iniae ECP vaccine in field Trial 3 was 91 and the RPS was 83. These results demonstrate that therapeutic immunization using S. iniae ECP and FKC+ECP vaccines can control a natural S. iniae infection. Furthermore, S. iniae ECP or FKC+ECP vaccines can also be used prophylacticly to protect hybrid striped bass against subsequent pathogen challenge. 相似文献
10.
Syed Shariq N. Qadiri Marappan Makesh Kooloth V. Rajendran Gaurav Rathore Chandra S. Purushothaman 《Journal of the World Aquaculture Society》2019,50(4):856-865
Mucosal immune barriers confer protection against invading fish pathogens. Here, we conducted an experiment for 60 days to assess the mucosal and systemic immune response in Mrigal (Cirrhinus mrigala), an Indian major carp. Fish were immunized with inactivated Edwardsiella tarda by four different routes, namely, oral, immersion, injection, and anal intubation. An indirect enzyme‐linked immunosorbent assay (ELISA) was used to measure the specific immune response (antibody) in serum and mucus (collected from skin, gill, and gut) of the fish on 0, 15, 30, 45, and 60 days postimmunization. For specific immune response in the serum, significantly higher (p < 0.05) optical density (OD) values were obtained in the anal group (0.52 ± 0.03) and in the oral group (0.48 ± 0.03). In the skin mucus, significantly higher OD values were obtained in the oral group (0.48 ± 0.04) and immersion group (0.32 ± 0.03). In the gill mucus, significantly higher OD values were obtained in the oral group (0.82 ± 0.08) and the immersion group (0.73 ± 0.03). In the gut mucus, significantly higher OD values were obtained in the immersion group (0.080 ± 0.007) compared to the rest of the treatments. Fish from all the groups were challenged with LD50 dose of E. tarda at the end of the experiment. We conclude that oral and immersion immunization routes offer better protection of C. mrigala compared to other antigen delivery routes. 相似文献
11.
Experimental infection and horizontal transmission of Piscirickettsia salmonis in freshwater-raised Atlantic salmon, Salmo salar L. 总被引：3，自引：0，他引：3
F.E. Almendras I.C. Fuentealba S.R.M. Jones F. Markham & E. Spangler 《Journal of fish diseases》1997,20(6):409-418
Experimental infections with Piscirickettsia salmonis via intraperitoneal (IP), oral (PO) and gill (GS) routes were compared, and the importance of physical contact in the horizontal transmission of this organism was investigated. Atlantic salmon, Salmo salar L., under-yearling parr raised in fresh water were used in this study. Samples of liver, kidney, spleen, gill and brain were collected weekly for 5 weeks after challenge, and were examined using the indirect fluorescent-antibody technique (IFAT). The pathogen was transmitted horizontally to fish with and without physical contact. However, transmission of P. salmonis occurred significantly more rapidly among fish with physical contact. Mortalities occurred in 50% of fish experimentally challenged with P. salmonis and their cohabitants. The estimates of the relative risk of dying demonstrated that fish challenged by the IP and GS routes had a significantly higher probability of dying than fish challenged by the PO route ( P < 0.005). Contact cohabitants with infected fish had a higher probability of death than non-contact cohabitants ( P < 0.005). The sequential studying using IFAT indicated that a haematogenous pattern of infection occurred among fish infected by oral and gill routes, or by cohabitation. This was different from the capsular (serosal) infection pattern observed in intraperitoneally inoculated fish. Piscirickettsia salmonis was observed within the cytoplasm of leucocytes and renal tubules, the latter indicating that elimination of this pathogen through the urine may be possible. Aeromonas salmonicida was also detected (by IFAT) in some of the fish exposed to P. salmonis , suggesting that P. salmonis may cause immunosuppression, and thus, increase the susceptibility of the host to other pathogens. 相似文献
12.
Age‐dependent susceptibility to nervous necrosis virus (NNV) was demonstrated for barramundi (Lates calcarifer). The experiment used juvenile barramundi produced from a single spawning that were challenged consecutively by immersion with a redspotted grouper nervous necrosis virus (RGNNV) isolate. The dose and environmental conditions (35 ppt salinity and 30 °C) were constant. Fish and water were sampled longitudinally for histopathology and RT‐qPCR analysis to examine the evolution of the disease, virus replication, immune response and release of virus into water. Viral nervous necrosis (VNN) disease occurred in barramundi challenged at 3 and 4 weeks of age while fish challenged at 5, 7 and 9 weeks of age developed subclinical infection. Replication of NNV occurred faster and the concentration of virus reached higher concentrations in the younger fish with clinical disease. Virus isolation and qPCR tests indicated that infectious NNV was released from carcasses into water when fish were affected with clinical disease but not when NNV infection was subclinical. Based on these observations, we consider that carcasses from clinically infected fish have a potentially important role in the horizontal transmission of NNV, and barramundi juveniles should be protected from exposure to NNV until they are 5 weeks of age and reach the disease resistance threshold. 相似文献
13.
《Journal Of Applied Aquaculture》2013,25(1-2):25-34
Lytic peptides have been shown in vitro to be toxic to a wide range of fish bacterial pathogens, including Edwardsiella ictaluri, the causative agent for enteric septicemia. Fingerling channel catfish, Ictalurus punctatus, were challenged with an injection of Edwardsiella ictaluri, and lytic peptide was administered with a single intraperitoneal injection 24 hours later. In a second group, lyptic peptide was also administered by osmotic pump 7 days before the bacterial challenge. A range of peptide concentrations (20-400µg/g fish) was used. Mortalities were recorded for 7 days after injection of bacteria, and E. icraluri was isolated and quantified by standard plate counts from livers. Various tissues were examined for abnormalities due to bacteria and peptide treatment. Fish injected with lytic peptide at 400 µg/g had up to a 95% reduction in bacteria and a 65% reduction in mortality compared to complete mortality in bacteria-injected controls. Fish implanted with osmotic pumps had 99.3% reduction in bacterial counts and had 6% mortality. Tissue samples from infected fish showed changes typical of reaction to immunologic stimuli and infection, while control fish injected with saline or peptide had normal gills, spleens, and kidneys. This study shows the potential for enhancing channel catfish disease resistance to E. ictaluri and other diseases by transferring the gene coding for the lytic peptide into channel catfish. 相似文献
14.
Influence of dietary carbohydrate on blood chemistry, immunity and disease resistance in Atlantic salmon, Salmo salar L. 总被引：7，自引：0，他引：7
Abstract. The influence of dietary carbohydrate (CHO) on blood chemistry, immunity and disease resistance was studied in two experiments with Atlantic salmon, Salmo salar L. Moist diets with increasing amounts of digestible CHO ranging from 0 to 30% (dry weight) were used. In the first experiment with adult (0.5 kg) fish, blood haemoglobin concentration was negatively correlated with increasing dietary CHO level, while serum glucose and protein did not differ between the groups. Serum cortisol increased linearly in fish fed from 5 to 30% CHO. Serum haemolytic activity was negatively correlated with dietary levels of CHO. Humoral immune responses elicited after vaccination by intraperitoneal injection or by dip immersion with Vibrio salmonicida showed no differences according to diet 10 and 17 weeks post-vaccination. Mortality after challenge with live Aeromonas salmonicida by intraperitoneal injection was lowest in fish fed 10% CHO. In the second experiment with juvenile Atlantic salmon (3g), there were minor differences in body and organ weights. Plasma glucose, protein and cholesterol were elevated in fish fed the highest CHO levels. Fish exposed to immersion challenge with different water concentrations of Vibrio anguillarum showed no statistical differences in mortality. The studies indicate that varying dietary levels of CHO affected immunity and resistance to bacterial infections to a minor extent in Atlantic salmon at low water temperatures during freshwater and seawater stages. 相似文献
15.
16.
The humoral immune responses and host protection of channel catfish, Ictalurus punctatus (Rafinesque), against Ichthyophthirius multifiliis (Ich) were determined after immunization with live theronts and sonicated trophonts. Immunizations with live theronts or sonicated trophonts were carried out by both bath immersion and intraperitoneal (i.p.) injection. Cutaneous and serum immunoglobulin (Ig) levels and anti-Ich antibodies were measured 12 and 21 days post-immunization. The level of Ich infection and survival of catfish were determined after theront challenge. Cutaneous and serum anti-Ich antibodies were significantly higher (P < 0.05) in fish immunized with live theronts by immersion or i.p. injection, or with sonicated trophonts administered by i.p. injection, than in fish immunized with sonicated trophonts by immersion, with bovine serum albumin by i.p. injection, or non-immunized controls. Host protection was noted only in fish immunized with live theronts by immersion or i.p. injection or with sonicated trophonts by i.p. injection. There was a positive correlation between higher levels of anti-Ich antibodies and host survival in the immunized fish. 相似文献
17.
Susceptibility of a number of Australian freshwater fishes to dwarf gourami iridovirus (Infectious spleen and kidney necrosis virus) 
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下载免费PDF全文 Megalocytiviruses cause high mortality diseases that have seriously impacted aquaculture, with the most frequent outbreaks occurring in East and South‐East Asia. The international trade of juvenile fish for food and ornamental aquaculture has aided the spread of these viruses, which have spread to Europe and Australia and other regions. Australian freshwater fishes were examined for susceptibility to infection with the exotic megalocytivirus, dwarf gourami iridovirus (DGIV), which belongs to a group with the type species, Infectious spleen and kidney necrosis virus (ISKNV). Fish were held at 23 ± 1 °C and challenged by intraperitoneal (IP) injection or by cohabitation with Murray cod, Maccullochella peelii (Mitchell) infected with DGIV. A species was deemed to be susceptible to DGIV based on evidence of viral replication, as determined by qPCR, and megalocytic inclusion bodies observed histologically. Horizontal transmission occurred between infected Murray cod and golden perch, Macquaria ambigua (Richardson), Macquarie perch, Macquaria australasica (Cuvier) and Murray cod. This indicated that DGIV shed from infected fish held at 23 °C can survive in fresh water and subsequently infect these naïve fish. Further, DGIV administered IP was highly pathogenic to golden perch, Macquarie perch and Murray cod. Compared to these species, the susceptibility of southern pygmy perch, Nannoperca australis (Gunther) was lower. Freshwater catfish (dewfish), Tandanus tandanus (Mitchell), were not susceptible under the experimental conditions based on the absence of clinical disease, mortality and virus replication. This study showed the potential risks associated with naïve and DGIV‐infected fish sharing a common water source. 相似文献
18.
Development,distribution and expression of a DNA vaccine against nodavirus in Asian Seabass,Lates calcarifier (Bloch, 1790) 下载免费PDF全文
下载免费PDF全文 S Vimal M A Farook N Madan S Abdul Majeed K S N Nambi G Taju N Sundar raj S Venu R Subburaj A R Thirunavukkarasu A S Sahul Hameed 《Aquaculture Research》2016,47(4):1209-1220
Fish nodavirus (betanodavirus), a viral pathogen responsible for viral nervous necrosis (VNN) was isolated from infected Asian sea bass (Lates calcarifer). The distribution, clearance and expression of nodavirus vaccine, on the basis of DNA vaccine (pFNCPE42 DNA‐pcDNA3.1) construction, were analysed in tissues of the Asian seabass by PCR, RT‐PCR, ELISA and Immunohistochemistry. Fish immunized with a single intramuscular injection of 20 μg of the pFNCPE42‐DNA vaccine showed a significant increase in the serum antibody level in the 3rd week after vaccination, compared to control eukaryotic expression vector pcDNA3.1 vaccinated fish. Results from PCR studies indicated that the vaccine‐containing plasmids were distributed in heart, intestine, gill, muscle and liver 10 days after vaccination. Clearance of pFNCPE42‐DNA vaccine was studied at 10, 25, 50, 75 and 100 days of post vaccination (d p.v). At 100 days p.v. pFNCPE42‐DNA was cleared from muscle of vaccinated sea bass. In vitro and in vivo expression of fish nodavirus capsid protein gene (FNCP) was determined by fluorescent microscopy. Asian seabass was immunized with pFNCPE42‐DNA vaccine at a dose of 20 μg per fish and were challenged with betanodavirus by intramuscular injection. The vaccinated seabass was protected from nodaviral infection and 77.33% of relative percent survival (RPS) was recorded. 相似文献
19.
Abstract. Aeromonas salmonicida , the aetiologic agent of furunculosis, causes high mortality in cultured salmonids. Experiments were conducted to determine the therapeutic and prophylactic efficacy of passive immunization against furunculosis in brook trout, Salvelinus fontinalis (Mitchill), infected by immersion. Rabbit hyperimmune serum was produced against a virulent strain of A. salmonicida and an aliquot of this serum was absorbed with cells of a non-virulent strain of A. salmonicida. Immunoglobulins from aliquots of the absorbed and non-absorbed serum were purified using affinity chromatography. Each serum or immunoglobulin preparation was tested in passive immunization experiments. Brook trout were infected by immersion in a suspension of virulent A. salmonicida , and passively immunized by intraperitoneal injection at the time of experimental infection, or at various periods after experimental infection. Passive immunization of brook trout against furunculosis was therapeutically efficacious when effected either at zero, 24 or 48h post-infection, but not at 72 or 96h. Purified rabbit immunoglobulins specific to virulent A. salmonicida were as protective as the initial rabbit hyperimmune serum in protecting brook trout against furunculosis. To determine the prophylactic efficacy of this treatment, the groups of fish passively immunized at the time of the experimental infection were challenged a second time at either 14, 35, 41 or 56 days after passive immunization. Brook trout were protected against a second experimental bath challenge with virulent A. salmonicida for a period of 35–41 days. 相似文献
20.
Immunization of channel catfish, Ictalurus punctatus Rafinesque, against Ichthyophthirius multifiliis (Fouquet): killed versus live vaccines 总被引：1，自引：0，他引：1
Abstract. Fish surviving infection with the pathogenic ciliated protozoan, Ichthyophthirius multifiliis (Fouquet, 1876), become resistant to subsequent infection by the parasite. The acquired immunity suggests that development of a vaccine against the parasite may be possible. Because of the advantages of immunoprophylaxis for treatment of the disease, an effort has been made to determine whether fish exposed to killed parasite preparations can resist subsequent lethal challenge. Both the route of administration and the effects of stage specific antigens have been examined. Channel catfish vaccinated by intraperitoneal (i.p.) injection or bath immersion with killed I multifiliis tomites show 100% mortality following a standard challenge protocol. Similarly, 100% mortality was observed in test groups injected with tomite cilia. In both cases, a consistent difference in days to death between control and test group animals was observed. Although complete mortality was seen with fish injected with tomite preparations, fish vaccinated with killed trophonts (the feeding stage of the parasite) had a much greater degree of protection with approximately 50% of fish surviving an otherwise lethal challenge. Finally, animals injected intraperitoneally with live tomites showed nearly complete immunity and were identical in their response to fish which survive natural infection. The response of fish vaccinated with live parasites indicates that animals injected intraperitoneally can develop surface immunity and that i.p. injection is a suitable route of administration for potential I. multifiliis vaccines. 相似文献