Morphological changes in brucellosis in guinea pigs due to experimental infection with Brucella suis

Sixty-four guinea-pigs were infected with the germs of Brucella suis. biotype 2 via the vaginal, peroral, intranasal, conjunctival and subcutaneous routes. In the subcutaneous infection the length of the trial was 151 days and in the other methods of infection 56 days. As found, guinea-pigs are highly sensitive and brucellosis lesions were detected in all cases. Brucellosis was chronical and spread locally in the guinea-pigs. In the haematogenic spreading of the disease, lesions were constantly recorded in liver, spleen and lungs. In the cases of subcutaneous infection lesions were also observed in regional lymph nodes at the places of infection. The lesions had amorphous structure and regular borders. The lesions were characterized by pronounced exudation and the exudate was subject to caseous necrosis, followed by colliquation. Secondary central colliquation was regularly observed in older granulomas, so that colliquation is considered as a characteristic morphological trait of brucellosis process in guinea-pigs. Histiocytary granuloma constituted the microscopic basis of the lesions. In older granulomas the central necroses were wide and contained a large amount of nuclear detritus, owing to the karyorhexis of cells, mainly neutrophiles. In the necroses of caseous type lipoid droplets were found and calcification was observed on the 151st day. Big cells of Langhans type occurred sometimes in the histiocytary layer of granulomas; they were present most frequently in the lesions affecting lymph nodes. Interstitial pneumonia was a characteristic symptom in liver and big cells of Sternberg type were found in the granulomas. Follicular tumor was constantly observed in spleens. Morphologically detectable lesions first developed in liver after about 7 days from conjunctival infection and subcutaneous infection, after 21 days from vaginal and intranasal infection, and after 28 days from peroral infection. In the case of subcutaneous infection, granulomas were found in the regional lymph nodes on the 14th day. The most expressive lesions in organs, mainly liver, were found from the 49th to 56th day from infection.     

Evaluation of the ELISA for the serological diagnosis of trichinosis in Canadian swine

An ELISA using a Trichinella spiralis spiralis excretory-secretory antigen was evaluated as a procedure for the diagnosis of trichinosis in swine in Canada. Field and experimental trials were carried out using both indirect serological (ELISA) and direct parasitological (pepsin-digestion) methods concurrently on serum and musculature, respectively, from each animal. The ELISA is a sensitive and specific test for the detection of Trichinella antibodies in porcine sera when present. The development of Trichinella antibodies appears to be dependent on the magnitude of the infection established, age of the infection when the animal is tested and the immunocompetence or response to infection of individual animals. False negative reactions were recorded in both field and experimental trials. In the field study, five of the 1009 swine examined were parasitologically positive with light infections ranging from 0.01 to 0.046 larvae per gram (la/g) of musculature yet all were serologically negative. Experimentally it was shown that Trichinella antibodies develop slowly, at least two to three months postinfection, in pigs with very light infections. Even in pigs which developed infections of 33 to 55 la/g of musculature, seroconversion occurred greater than 23 and less than 30 days postinfection. The immunocompetence or response to infection of individual pigs was variable as illustrated by one pig inoculated with 3000 infective larvae which had consistently lower titers compared to others in the same group despite the establishment of a muscle infection of 8.5 la/g of musculature. One false positive reaction was recorded in the experimental trial in an animal which had received 100 larvae and seroconverted at about three months postinfection.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hematology and clinical pathology of experimental Fascioloides magna infection in cattle and guinea pigs.

The hematologic and clinico-pathologic response to Fascioloides magna infection in cattle and guinea pigs was investigated. Twelve calves (six infected and six controls) were monitored for 26 weeks after inoculation with 1000 metacercariae. All calves remained healthy and there were no significant differences in weight gains between infected and control groups. Flukes (mean = 9.2, range 1–32) were recovered from the liver and abdominal cavity of all infected calves. The only significant response observed in the complete blood counts was an eosinophilia present in the infected calves extending from Weeks 2 to 26 post-infection. There were no significant differences in serum levels of aspartate aminotransferase and only minor increases in the levels of gamma-glutamyl transferase and sorbitol dehydrogenase.

A total of 48 infected and 48 control guinea pigs from three separate experiments were monitored for 16 weeks after inoculation with 20 metacercariae of Fascioloides magna. Infected guinea pigs died between 7 and 114 days after infection, and flukes (ean = 2.5, range 0–13) were recovered from the liver, abdominal cavity, lungs, thoracic cavity, skeletal muscle and subcutaneous tissue. There were no differences in weight gains between infected and control guinea pigs. Complete blood counts showed increases in white blood cell, monocyte and neutrophil counts from between the third and fourteenth weeks post-infection; however, the differences were not consistently significant. Infected guinea pigs developed a significant eosinophilia and basophilia from 2 to 16 weeks post-infection. There were no significant changes in the serum levels of alanine aminotransferase or gamma-glutamyl transferase. There was an increase in the serum levels of aspartate aminotransferase beginning at 5 weeks post-infection. The response observed in the guinea pigs was similar to that reported in sheep, suggesting the suitability of the guinea pig as a model for Fascioloides magna infection in the sheep.     

Studies on the antigenicity of an inactivated, aluminum hydroxide adjuvant equine influenza vaccine.

An inactivated, aluminum hydroxide adjuvant equine influenza vaccine was tested in horses and guinea pigs to determine the levels of antigen that would elicit maximum serological responses. Vaccine containing serial twofold increments of A/Equi-1/Prague and A/Equi-2/Miami strains of equine influenza virus was administered to random groupings of both types of test animals. The hemagglutination inhibition antibody response for each group was then measured. Results in horses and guinea pigs were compared to determine if the equine serological values could be related to a potency test in laboratory animals. The highest mean hemagglutination inhibition antibody response in horses occurred in groups vaccinated, respectively, with 128 or 256 hemagglutination units of A/Equi-1 and 512 or 1024 hemagglutination units of A/Equi-2 antigen. Groups vaccinated with further two- or fourfold increases in these antigens had mean hemagglutination inhibition titers that were somewhat lower than the maximum levels. When graded doses of vaccine were given to guinea pigs, their hemagglutination inhibition antibody titers reached a plateau of maximum values, similar to the serological response in vaccinated horses. Test horses remained clinically free from signs of equine influenza during the year following vaccination and no untoward post-vaccination reactions were observed.     

Cell-mediated immune responses differentiate infections with Brucella suis from Yersinia enterocolitica serotype O:9 in pigs

Due to almost identical lipopolysaccharide (LPS) O-antigens, infections with Yersinia enterocolitica serotype O:9 (YeO:9) cause false positive serological reactions (FPSR) in tests for Brucella and thus cause problems in National Brucella surveillance programs. As LPS are strong inducers of antibody responses it was hypothesized that cell-mediated immune responses to non-LPS antigens of the two bacteria can be used to separate immune responses to these two biologically very different infections. Following subclinical experimental infections with Brucella suis biovar 2, high interferon-gamma (IFN-gamma) assay responses with a commercial Brucella melitensis antigen preparation (Brucellergene OCB) preceded the development of antibodies. High IFN-gamma responses in the seven B. suis inoculated pigs with serological evidence of infection were consistent throughout a 20-week post-inoculation observation period. In contrast, IFN-gamma responses in two B. suis inoculated pigs without bacteriological or serological evidence of infection were below a cut-point of 25pg/ml at all samplings. IFN-gamma responses in repeated samplings from 5 uninfected control pigs and 18 pigs experimentally infected with YeO:9 were all negative, except for solitary false positives in 3.7% of the samples from both the experimentally YeO:9 infected pigs and control pigs. Skin tests using the same commercial Brucella antigen confirmed the ability of cell-mediated immune responses to differentiate between the two infections. In addition, a field evaluation of the diagnostic use of cell-mediated immune responses by IFN-gamma assay and skin test to resolve serological suspicions of Brucella was conducted in an YeO:9 infected pig herd. Following a screening of 200 pigs 39 pigs were identified with false positive serological Brucellosis reactions. While 36 of the 39 FPSR pigs were also FPSR in a second test, none of the pigs were test positive in whole blood IFN-gamma assay or Brucellergene OCB skin test. In conclusion, use of IFN-gamma assay and skin test as measurements of cell-mediated immune responses to non-LPS Brucella antigens were specific and sensitive in discriminating subclinical experimental infections with B. suis from both natural and experimental infections with YeO:9.     

Development of an ELISA procedure to detect swine carriers of pathogenic Yersinia enterocolitica

An enzyme immunoassay (ELISA) was developed to detect antibodies in pigs against the lipopolysaccharidic antigen of the three serotypes of Yersinia enterocolitica mostly associated with human infections. Recent epidemiological evidence has demonstrated that pigs and pork are important sources of yersiniosis in humans. The purpose of this study was to clarify the use of an ELISA to detect swine carriers of this enteroinvasive bacteria by examining seroconversion and tissue distribution of Y. enterocolitica following experimental infection and then screening pigs at a slaughterhouse by bacterial culture and ELISA. It was observed that seroconversion occurred in animals experimentally inoculated with Y. enterocolitica but not with other enterobacteria. It was also found that 27% of swine at a slaughterhouse carried the bacterium in their tonsils and/or intestinal tract, whereas 66% showed serological evidence of previous infection. About 6% of swine at slaughter were culture-positive, but seronegative. Although, similar numbers of swine showed serological evidence of previous infection by each of the three Y. enterocolitica serotypes tested, virtually all culture isolates belonged to serotype O:3. This ELISA appears as a valuable control tool that can be used, in conjunction with culture, to identify pigs or herds infected by strains of Y. enterocolitica associated with human infections.     

Peroral infection of pigs with Schistosoma japonicum cercariae.

Infections with the zoonotic trematode, Schistosoma japonicum in pigs serves as a valuable model for studying natural definitive host/parasite relationships and a model for human schistosomosis japonica. In the present study the efficiency of a peroral infection route was compared with that of an intramuscular route of infection. Eleven specific pathogen-free Danish Landrace/Yorkshire/Duroc crossbred male and female pigs were divided into two groups of five and six pigs, respectively. Each pig was given 1000 cercariae, either placed in droplets on the mucosa in the buccal cavity, or as medium-suspended cercariae injected into musculus biceps femoris of one of the hindlegs. Ten weeks post infection, all pigs were killed with pentobarbital and the venous system perfused. Worm burdens and liver egg counts were determined and worm fecundity was calculated. S. japonicum infections were established in all individuals in both groups of pigs. When comparing the two groups, the peroral group had significantly higher number of immature worms, whereas the intramuscularly infected group had significantly more worm nodules. However, no difference was seen in total number of worms. No statistical significant differences were found in neither tissue egg counts nor worm fecundity when comparing the two groups. The results from the present study showed a delay in maturation of infection following a peroral infection as compared with an intramuscular infection, but comparability was seen between overall worm establishment and egg production.     

Humoral immunity in the prepatent primary infection of dogs with Echinococcus granulosus

Twenty-one parasite-naive dogs were infected with 60,000 protoscolices of Echinococcus granulosus. Transformation of peripheral lymphocytes was investigated before and 29 days after the infection, immunoglobulin concentration and anti-hydatid fluid protein (HFP) titers in serum and feces before and at 35 days of infection, skin reactivity to HFP at 36 days, and characteristics of the parasites at 40 days. The infection caused a significant depression of the spontaneous, lipopolysaccharide-stimulated, and purified protein derivative-stimulated blastogenesis. Responses to phytohemagglutinin were unchanged and reactivity to concanavalin A was enhanced with the infection. Only the concentrations of IgG and IgA in the serum and IgA in the feces increased significantly after infection. Fifteen (71%) dogs produced significant serum titers of anti-HFP hemagglutinins but copro-antibodies were detectable in only 3 dogs at minimum titers. Titers were abolished by treatment with 2-mercaptoethanol. The serum of 11 (52%) dogs transferred passive cutaneous anaphylaxis to guinea pigs but none transferred skin reactivity to pups or rabbits. Five and 1 (but not 0.2) micrograms of HFP caused skin reactivity in 4 parasite-naive dogs. Nineteen (90.5%) infected dogs reacted significantly to skin inoculation of 0.2 microgram of HFP at 0.5 hours and 13 (62%) at 6 hours. The 7 dogs with the highest anti-HFP serum titers or the greatest skin reactivity at 6 hours had significantly less mature or fewer tissue parasites, respectively, than the 7 dogs with the smallest responses. Since there was evidence that the specific immunity was still developing at the time of the study, these results indicate that immunological diagnosis of, and artificial immunization against, canine echinococcosis are feasible.     

抗独特型抗体对猪繁殖与呼吸综合征病毒感染的免疫作用

用PRRSV感染SPF猪，血清检测结果显示，机体不仅产生抗PRRSV抗原的各种抗体(Ab1)，而且产生针对这些抗体的抗独特型抗体(Ab2)。根据各种蛋白质的等电点不同，应用IEF技术分离纯化出PRRSV感染猪血清中的不同IgG。分别以纯化的抗PRRSV—GP5蛋白、抗PRRSV-M蛋白的Ab2免疫SPF猪各5头，7d后经鼻腔感染PRRSV，定期采集血样进行病毒分离或鉴定试验。抗PRRSV-GP5蛋白的Ab2免疫的猪，其血样自感染后3～7d均检出PRRSV；3头猪在感染后14～63d未检出PRRSV；2头猪在感染后14～35d检出PRRSV，从42～56d转为阴性，其中1头猪在63d时检出PRRSV。抗PRRSV—M蛋白的Ab2免疫的猪，其血样自感染后3～7d均检出PRRSV；2头猪在感染后14～63d未检出PRRSV；3头猪在感染后14～35d检出PRRSV，从42～56d转为阴性，其中1头猪在63d时检出PRRSV。抗PRRSV—GP5和抗PRRSV—M蛋白的Ab2免疫作用显著，可作为PRRSV-GP5和PRRSV—M蛋白的替代抗原产生具有中和效应的抗体，保护机体免受PRRSV的感染。     

The Susceptibility of Muskrats and Snowshoe Hares to Experimental Infection with a Chlamydial Agent

Muskrats (Ondatra zibethicus) and snowshoe hares (Lepus americanus) were exposed experimentally by various routes to a chlamydial agent (designated strain M56) originally isolated during a die-off of muskrats and snowshoe hares which occurred in Saskatchewan during 1961. Both species were susceptible to experimental infection. Whereas M56 was highly lethal for snowshoe hares (18 deaths/19 exposed), it was less virulent for muskrats (6 deaths/20 exposed).

The degree of susceptibility of muskrats to induced infections with M56 was influenced by the presence or absence of specific antibodies at the time of exposure. A febrile illness was observed in 11 of 20 muskrats. In the six that died, widespread focal necrosis was found in the liver. Following intraperitoneal or oral exposures, chronic infections were established and the agent was recovered from the brain and the small intestine up to 96 days post-infection. Specific antibodies were found in 11.8% of 127 sera of muskrats trapped form the wild in Saskatchewan, the Canadian Arctic, and Wisconsin.

In snowshoe hares, M56 induced an acute, febrile, emaciating illness, and the almost invariable fatal course was short with terminal signs of opisthotonos, convulsions, and hypoglycemia. Snowshoe hares succumbed with intravenous doses of less than ten mouse intracerebral LD₅₀ of M56. The same syndrome was produced by intravenous, subcutaneous, and oral infections. M56 was found in high titers in all tissues examined. The highest titers were found in the liver and spleen which correlated with the pathology observed. M56 was recovered from female rabbit ticks (Haemaphysalis leporispalustris) engorging on experimentally infected snowshoe hares.

     

Swine influenza virus infection dynamics in two pig farms; results of a longitudinal assessment

ABSTRACT: In order to assess the dynamics of influenza virus infection in pigs, serological and virological follow-ups were conducted in two whole batches of pigs from two different farms (F1 and F2), from 3 weeks of age until market age. Anti-swine influenza virus (SIV) antibodies (measured by ELISA and hemagglutination inhibition) and nasal virus shedding (measured by RRT-PCR and isolation in embryonated chicken eggs and MDCK cells) were carried out periodically. SIV isolates were subtyped and hemagglutinin and neuraminidase genes were partially sequenced and analyzed phylogenetically. In F1, four waves of viral circulation were detected, and globally, 62/121 pigs (51.2%) were positive by RRT-PCR at least once. All F1 isolates corresponded to H1N1 subtype although hemagglutination inhibition results also revealed the presence of antibodies against H3N2. The first viral wave took place in the presence of colostral-derived antibodies. Nine pigs were positive in two non-consecutive sampling weeks, with two of the animals being positive with the same isolate. Phylogenetic analyses showed that different H1N1 variants circulated in that farm. In F2, only one isolate, H1N2, was detected and all infections were concentrated in a very short period of time, as assumed for a classic influenza outbreak. These findings led us to propose that influenza virus infection in pigs might present different patterns, from an epidemic outbreak to an endemic form with different waves of infections with a lower incidence.     

Swine vesicular disease, studies on pathogenesis, diagnosis, and epizootiology: a review

Swine vesicular disease (SVD) is a contagious viral disease of swine. It causes vesicular lesions indistinguishable from those observed of foot-and-mouth disease. Infection with SVD virus (SVDV) can lead to viraemia within 1 day and can produce clinical signs 2 days after a pig has come into contact with infected pigs or a virus-contaminated environment. Virus can be detected 3.5 hours after infection using immunohistochemistry. In these in vitro studies, this technique was superior to in-situ hybridization. In SVDV-infected tissues, however, more infected cells were positive using in-situ hybridization, and these were already seen 4.5 hours after infection. For serological diagnosis of SVD several new enzyme-linked immunosorbent assays (ELISA's) have been developed. The newest ELISAs, based on monoclonal antibodies, are superior to the previous tests. The new tests produce fewer less false-negative results and enable large-scale serological screening. In screening programmes a small percentage of false positive reactors have been detected. The cause of these false-positive reactions has not been identified, though infections with human Coxsackie B5 virus can be excluded.     

Development of a complete ELISA using Salmonella lipopolysaccharides of various serogroups allowing to detect all infected pigs

Although poultry is recognized as the major source of food-poisoning caused by Salmonella, pork also contributes to human infections. This study was therefore undertaken in order to develop a reliable serological method for the evaluation of the Salmonella status of piglets. A complete ELISA was performed using lipopolysaccharides of Salmonella Typhimurium, Anatum, Hadar and Infantis because these serovars were representative of the serogroups isolated from 30 contaminated fattening farms. S. Enteritidis was also added because of its importance in human infection and to include the O:9 antigen. This method potentially detects 100% of infected pigs. A significant correlation was found between this serological method and the bacteriological data from mesenteric lymph nodes (p = 0.01). In addition, both sensitivity and specificity were high (97% and 94% respectively). The ELISA test was therefore used in a cross-sectional study on 4 farms to evaluate when pigs became contaminated: seropositive pigs were only found for the 20 week old finishing pigs. The antibody response to Salmonella in piglets was also investigated: maternal antibodies persisted until 7 weeks of age and post-Salmonella contamination seroconversion was detected from 8 weeks of age onwards.     

Epidemiology and control of Menangle virus in pigs

OBJECTIVE: To describe the epidemiology and eradication of Menangle virus infection in pigs. DESIGN: Field observations and interventions, structured and unstructured serological surveys, prospective and cross-sectional serological studies and laboratory investigations. PROCEDURE: Serum samples were collected from pigs at a 2600-sow intensive piggery in New South Wales that experienced an outbreak of reproductive disease in 1997. Serum samples were also collected from piggeries that received pigs from or supplied pigs to the affected piggery and from other piggeries in Australia. Serum and tissue samples were collected from pigs at piggeries experiencing reproductive disease in New South Wales. Sera and faeces were collected from grey-headed flying foxes (Pteropus poliocephalus) in the region of the affected piggery. Serum samples were tested for neutralising antibodies against Menangle virus. Virus isolation was attempted from faeces. RESULTS: Following the outbreak of reproductive disease, sera from 96% of adult pigs at the affected piggery, including sows that produced affected litters, contained neutralising antibodies against Menangle virus. Neutralising antibodies were also detected in sera from 88% of finisher pigs at two piggeries receiving weaned pigs from the affected piggery. No evidence of Menangle virus infection was found in other piggeries in Australia. In cross-sectional studies at the affected piggery, colostral antibodies were undetectable in most pigs by 14 to 15 weeks of age. By slaughter age or entry to the breeding herd, 95% of pigs developed high antibody titres (> or = 128) against Menangle virus in the virus neutralisation test. Menangle virus was eradicated from the affected piggery following a program of serological testing and segregation. Neutralising antibodies against Menangle virus were also detected in P poliocephalus from two colonies in the vicinity of the affected piggery. Two piggery workers were infected with Menangle virus. There was no evidence of infection in cattle, sheep, birds, rodents, feral cats and a dog at the affected piggery. CONCLUSIONS: Serological evidence of infection with Menangle virus was detected in pigs at a piggery that had experienced reproductive disease, in pigs at two associated piggeries and in fruit bats in the region of the piggery. Two humans were infected. The mode of transmission between pigs is unknown, but spread by faecal or urinary excretion is postulated. This virus can be eradicated by the segregation of pigs into discrete age groups.     

Seroprevalence of Actinobacillus (Haemophilus) pleuropneumoniae serotype-1 infection in swine herds in Quebec

Seroprevalence of Actinobacillus (Haemophilus) pleuropneumoniae serotype-1 infection was evaluated in pigs on 7 farms in Quebec. Commercial cross-bred herds A to G, ranging from 110 to 235 sows and infected with A pleuropneumoniae serotype-1 were selected. Five pigs/litter were selected at random and were identified (group 1). Blood samples were obtained from group-1 pigs at 2 to 4, 14, 28, 42, and 56 days of age. Blood also was obtained from group-1 pigs remaining in the postweaning unit at 70 days of age, and from 20 to 40 sows 1 to 3 times. To determine prevalence of seropositive pigs in all age groups for the entire study period in herds C to G, blood samples were obtained from 20 pigs/age group (group 2) selected at random at 28, 42, and 56 days of age at each visit. Group-1 pigs were included when they reached 28, 42, and 56 days of age. Pigs were serologically monitored in herds A and B for 3 months and in herds C to G for 5 to 6 months. Serologic status of pigs at 2 to 4 days of age was not statistically associated with status at 42 days (P = 0.6293) and at 56 days (P = 0.3098) of age for the same pigs. Therefore, seronegative pigs 2 to 4 days old did not seroconvert earlier than did those with detectable maternal antibodies at 2 to 4 days old. Only about 50% of the 70-day-old pigs were seropositive at 56 days. Seemingly, pigs seroconverted late in the postweaning period.(ABSTRACT TRUNCATED AT 250 WORDS)     

豚鼠副猪嗜血杆菌感染动物模型的建立

为建立副猪嗜血杆菌(Hps)的感染动物模型,本试验用Hps血清5型标准菌株(Nagasaki),以2.0×10~9CFU剂量腹腔感染豚鼠,观察豚鼠发病及死亡情况.取死亡豚鼠的主要器官组织,观察其病理和组织病理变化,与猪Classer's病痛变进行比较.并同时对死亡豚鼠进行细茵分离,分离菌经PCR鉴定.实验结果显示:在接种14 h后试验组豚鼠(5/8)出现死亡,死亡豚鼠剖检时出现了与猪Classer's病相似的病变;主要组织器官组织学变化以炎性细胞浸润、纤维蛋白和红细胞渗出等变化;并通过细茵分离培养,在豚鼠大脑、心血、肺、肝、脾和肾主要器官中分离到Hps血清5型茵.实验结果表明豚鼠可以作为Hps的感染动物模型.这一结果为研究其致病机制、诊断和免疫研究奠定基础.     

The Response of Colostrum-Deprived, Specific Pathögen-Free Pigs to Experimental Infection with Teschen Disease Virus

The clinical response to Teschen disease and the excretion and rate of virus distribution in tissues of colostrum-deprived, specific pathogenfree pigs was determined. Severe, mild, and clinically inapparent responses to the disease were noticed following simultaneous intracranial and intranasal infections. Fourteen-day-old pigs reacted more severely to infection than 21-day-old pigs. The virus was detected in feces 2-3 days following infection but not in stools of surviving pigs 30 days after infection. The highest concentration of virus occurred during the incubation period and before onset of paralysis; the lowest concentrations were found during terminal disease stages. In tissues collected before or immediately after death of pigs, Teschen disease virus was found in several visceral organs but not in blood, urine or urinary bladder tissue. Virus yield was highest in brain and spinal cord tissues. Highest virus concentration was found in the cervical thoracic portions of the spinal cord, thalamus and cerebellum. Other aspects of the clinical disease are discussed.     

Progression of Mycoplasma hyosynoviae infection in three pig herds. Development of tonsillar carrier state, arthritis and antibodies in serum and synovial fluid in pigs from birth to slaughter

In this investigation, natural infection with Mycoplasma hyosynoviae was followed in groups of individual pigs in three different herds with regard to occurrence of tonsillar carrier state, clinical arthritis and development of antibodies in serum and in synovial fluid. Antibodies were detected by a polyclonal enzyme-linked immunosorbent assay (ELISA) developed for experimental use. The infection with M. hyosynoviae progressed very differently in the three herds investigated. In one herd, the infection was apparently limited to adult pigs. In a second herd, all pigs became tonsillar carriers of M. hyosynoviae, but no mycoplasma-related arthritis nor any serological response was demonstrated within the growing-finishing period. In the third herd investigated, tonsillar infection was detected in all pigs, clinical cases of M. hyosynoviae arthritis followed and a moderate serological response was observed in some, but not all, pigs. In all three herds, M. hyosynoviae infection was carried in the tonsils of the adult pigs, but it was only occasionally transmitted from sows to piglets. Maternal antibodies were transferred to the piglets and persisted for approximately 8-12 weeks. After weaning, some pigs became infected before 20 weeks of age, while others did not. In the majority of cases, the tonsillar infection was established from 11 weeks of age or older. A latent tonsillar infection was present for a period of several weeks within the group of investigated pigs before cases of generalized infection and arthritis were seen. In some cases, generalization of M. hyosynoviae infection in the blood and in joints was observed in spite of the detection of an active serological response a few weeks earlier. The present work suggests that generalization of the infection and development of arthritis may depend on age, immunity, virulence factors and/or infection pressure; in some herds maybe combined with certain triggering mechanisms such as stress and lowered general resistance.     

布鲁菌在豚鼠和奶牛体内诱导的抗体水平和变态反应强度的相关性

为探索布鲁菌在豚鼠和奶牛体内所引起的抗体水平和变态反应强度的相关性,分别用1×104,3×104CFU牛种布鲁菌强毒2308株各感染12只豚鼠,30 d后测定抗体滴度和变态反应强度。感染后35 d,扑杀豚鼠,取脾脏测定每克脾脏含菌量。用布鲁菌A19疫苗,以5×1010CFU皮下注射布病阴性荷斯坦奶牛50头,分别于免疫后15,30,60 d测定抗体滴度,并于免疫后45 d测定变态反应强度。运用SPSS 17.0-Analyze-Correlate-Bivariate Corre-lations程序分析试验数据,结果显示,不同剂量布鲁菌2308感染豚鼠后30 d所诱导的抗体水平、变态反应强度和克脾脏含菌量三者之间均无相关性。A19疫苗免疫奶牛后60 d的抗体水平与免疫45 d的变态反应强度呈正相关,免疫15 d和30 d的抗体水平和变态反应强度无相关性。豚鼠试验结果表明,抗体水平、变态反应强度与个体对布病的抵抗力均无相关性。     

Detection of antibodies against Brucella in the aqueous humor using ELISA

In aqueous bulbi of experimentally against Brucella abortus immunized guinea pigs and rabbits specific antibodies could be detected by ELISA-tests. This first demonstration of brucella antibodies in the aqueous shows that aqueous can be used for serological examinations. For practical use more investigations in experimental animals are necessary, e.g. on kinetics of orbital antibodies absence of interfering factors and biomechanics of proteins in aqueous.