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1.
This study investigated whether a precise and repeatable quantification of Heterakis gallinarum egg excretion, which considerably reflects the actual worm burdens, can be achieved based on collection of the daily total amount of faeces from chickens. Three-week-old birds (N=64) were infected with 200 embryonated eggs of H. gallinarum, and placed into individual cages 3 wk after infection for 5 wk to collect daily faeces (N=2240). The total daily faeces was mixed and a randomly taken sample per bird was analyzed to estimate the numbers of eggs per gram of faeces (EPG) and total number of eggs excreted within 24h (EPD). A total of 235 daily faecal collections were randomly selected and further examined to determine between and within sample variations of EPG counts as a measure of precision. For this, two random faecal samples were taken from the daily produced faeces by a bird, and the EPG was determined for each of the samples (EPG1 and EPG2). The second faecal sample was analyzed once more to determine a parallel EPG2 count (EPG2a) of the suspended sample. Precision of an EPG count was defined as its relative closeness to the average of two EPG counts using a relative asymmetry index (Index(EPG)). At an age of 11 wk, i.e. 8 wk p.i. the birds were slaughtered and their worm burdens were determined. There were no significant differences between EPG1 and EPG2 (P=0.764) nor between EPG2 and EPG2a (P=0.700), suggesting that the differences between or within the samples were not different from zero. Correlations between EPG counts, as between and within sample coherences, were r=0.85 and r=0.86, respectively. Precision of EPG counts, as measured by Index(EPG), was not influenced by consistency (P=0.870) and total amount of faeces (P=0.088). However, concentration of eggs in faeces (mean EPG) had a significant effect on the precision of the EPG counts (P<0.001). Similar results were also observed for the within sample precision (Index(EPG2)). A segmented regression analysis indicated an abrupt change in the precision of EPG counts as the response to changing egg concentration in the examined faecal samples. The precision of analyses remarkably heightened up to a breakpoint with an EPG count of ≤ 617. A similar breakpoint was also determined for within sample precision (EPG2 ≤ 621). Moderate repeatabilities (R=0.49) for EPG and EPD were estimated in the first week of egg excretion, whereas the estimates were higher (R=0.67-0.84) in the following weeks. Correlations between number of female worms with daily measured EPG and EPD increased to an almost constant level (r ≥ 0.70; P<0.05) in a few days after the nematode excreted eggs and predominantly remained so for the rest of the sampling period. It is concluded that mixing daily total faeces provides samples with random homogenous distribution of H. gallinarum eggs. Precision of the EPG counts increases as the egg concentration in faecal sample increases. Egg excretion of H. gallinarum, quantified either as EPG or EPD, is highly repeatable and closely correlated with the actual worm burden of birds starting as early as in 5 th wk of infection.  相似文献   

2.
A mixed inoculum of C. pyogenes, P. indolicus and a microaerophilic coccus was used to induce experimental mastitis in two heifers. During the course of the infection, the IgG titres against these bacteria were monitored by the indirect immunofluorescent antibody technique. At the same time, the course of the infection was studied bacteriologically and by determination of clinical-chemical parameters. In both heifers, high titres of IgG against C. pyogenes, P. indolicus and the microaerophilic coccus were detected. The reactivity of the IgG towards surface-associated antigens of these bacteria seemed to reside mainly in the IgG2 subclass. Sera obtained from Denmark from heifers with experimental mastitis, which had been induced similarly, were also found to have significantly raised IgG titres against C. pyogenes and P. indolicus. Sera from naturally infected heifers and dry cows, from whose udder secretions C. pyogenes and P. indolicus had been isolated, were examined comparatively with sera from healthy heifers and dry cows, respectively, for the presence of IgG against these two bacteria. Statistically significant differences in IgG titres against both bacteria were demonstrated between pregnant heifers with mastitis and healthy pregnant heifers and between dry cows with mastitis and clinically healthy controls.  相似文献   

3.
Prevalence studies have shown that almost 100% of free-range chickens are infected with a wide range of parasites. The infections are mostly subclinical in nature, resulting in production losses and occasionally mortality. Newcastle disease (ND), on the other hand, results in high mortality rates during epidemics. ND is a limiting factor for increasing poultry production in many tropical countries, where frequent reports indicate vaccination failures. The aim of our study was to investigate the influence of helminths on the antibody response after vaccination against Newcastle disease of free-range chickens naturally infected with parasites. Sixty chickens were divided into six groups, of which three were vaccinated against ND with a live De Soto vaccine, while the other three remained non-vaccinated. One group within the vaccinated groups and the one within the non-vaccinated group was kept naturally infected with helminth parasites, while the other two groups in each set were dewormed with fenbendazole and niclosamide, and one of each of these groups was subsequently infected with Ascaridia galli. After vaccination, all the groups were followed for 5 weeks and their antibody titres were determined weekly using a HI test. All the birds were finally challenged 4 weeks after vaccination with a virulent velogenic ND virus obtained from a field outbreak. All the vaccinated chickens seroconverted and had high antibody levels after 3 weeks, but these dropped to low levels at 4 weeks after vaccination. After challenge, the antibody titres rose in the dewormed groups but not in the parasite-infected groups. After 5 weeks, all the parasite-infected animals had significantly lower antibody titres than the dewormed animals. All the vaccinated chickens survived the challenge infection, emphasizing the importance of the cellular immune response. Further studies are needed to examine the effects of the parasitic infection on protection against ND over a longer period.  相似文献   

4.
文昌鸡生态放养过程中驱虫程序的研究   总被引：1，自引：0，他引：1  
采用虫卵漂浮法、麦克马斯特氏虫卵计数法对文昌鸡生态放养期间感染寄生虫的种类与粪便中虫卵数量进行监测。结果表明,文昌鸡生态放养感染的寄生线虫主要为鸡蛔虫和几种异刺线虫。自然条件下生态放养35 d后,每克粪便中寄生虫虫卵数（eggs per gram, EPG）达到了700,呈显著增长趋势。抽样宰杀30只鸡,检出18只感染鸡蛔虫成虫,感染率为60％,平均感染强度为8条/只。因此,建议整个生态放养期间驱虫3～4次为宜,首次驱虫时间为放养后25～30 d。  相似文献   

5.
Addition of anti-immunoglobulin M (anti-IgM), G (anti-IgG) and A (anti-IgA) sera to the haemagglutination-inhibition (HI) test (anti-Ig HI test) forMycoplasma gallisepticum resulted in 2- to 8-fold increases in the HI titres. On investigating the anti-Ig HI reaction using IgM and IgG antibodies separated by affinity chromatography, it was confirmed that, in the enhanced HI titres, specificity existed between the chicken Ig classes having antibody activity and the antisera used in the test. Four days after inoculation ofM. gallisepticum, the anti-Ig HI reaction was markedly enhanced by anti-IgM antiserum in the intravenously inoculated chickens and by anti-IgA serum in the nasally inoculated chickens. Ten days after inoculation ofM. gallisepticum marked enhancement of the reaction was produced by anti-IgG serum in both intravenously and nasally inoculated chickens, but the enhancement of the anti-Ig HI reaction diminished from the second week after inoculation.  相似文献   

6.
The aims were (a) to quantify the number of Duddingtonia flagrans chlamydospores per gram of faeces (CPG) recovered from sheep administered with different oral doses and, (b) to describe the relationship between CPG and eggs per gram of faeces (EPG) on the efficacy to reduce Haemonchus contortus infective larvae. Three doses of chlamydospores per kg BW were orally administered during seven days: (T1) non treated control group, (T2) 1 × 106, (T3) 2.5 × 106 and (T4) 5 × 106. Three lambs, infected with H. contortus, were used per group. Faeces were obtained from the rectum of each lamb during the fungal administration period (days 0–6) and for six days after that period. Four coproculture replicates were made from each animal in days 2, 4, 6, 8 and 10. A higher chlamydospore dose produced higher CPG in faeces (p < 0.05), but a clear dose dependent effect was not found either in the larvae reduction or in the CPG:EPG ratio. When ratios were re-analyzed, independently of the treatment groups of origin, a better efficacy was obtained with a ratio from 5 to 10 CPG:EPG and a higher ratio (>10 per egg) showed a lower reduction efficacy (p < 0.05). The binomial analysis showed that for each unit of increment in CPG:EPG ratio there was a reduction of larvae number until a point (between 5 and 10 CPG:EPG) where no further reduction was detected. The surface response test indicated that the number of larvae was reduced by CPG until possible saturation. The highest CPG:EPG ratios did not necessarily improve efficacy of D. flagrans.  相似文献   

7.
Six-day-old embryonated specific pathogen free chicken eggs were inoculated with reticuloendotheliosis virus (REV) into the yolk sac and were incubated until they hatched. The hatchability of eggs inoculated with REV was significantly less (P less than 0.025) than that of media-inoculated controls. Although there were no significant differences in the body weights of these chickens at hatching, there were differences (P less than 0.001) at 6, 25 and 51 days of age between the infected and control chickens. Six of 10 chickens hatched from eggs inoculated with REV had feathering defects at 6 days of age. All chickens hatched from infected eggs had cell-free viraemia and antigenaemia, but not precipitating antibodies. Some of these chickens had very low neutralising antibody titres (less than 45) when examined at 25 and 37 days of age, as did all 10 chickens at 51 days of age. A low rate of horizontal transmission was indicated by the detection of antibodies at 37 and 51 days of age in chickens running in contact with the chickens hatched from eggs inoculated with REV.  相似文献   

8.
We analyzed the nuclear ribosomal internal transcribed spacer (ITS) 1 and ITS2 sequences for Bangladesh isolates of Ascaridia galli, and we determined that the sequences were unreliable as molecular markers for distinguishing A. galli from other Ascaridia species, because the sequences showed high identity with that of A. columbae. However, the ITS1 sequences were available for designing PCR primers distinguishable between Ascaridia galli and Heterakis spp. Bangladesh isolates of A. galli constituted a monophyletic clade along with other geographical isolates in the cytochrome c oxidase subunit I (COI) phylogenetic tree, however, we could not clarify the phylogenetic relationships between A. galli and other Ascaridia spp., because their available sequences in GenBank were very few. The developed PCR method using DNA from A. galli and Heterakis spp. eggs would enable differential diagnosis of the individual infections in the future.  相似文献   

9.
Chickens raised under village production systems are exposed to a wide variety of pathogens, and current or previous infections may affect their susceptibility to further infections with another parasite, and/or can alter the manifestation of each infection. It is possible that co-infections may be as important as environmental risk factors. However, in cross-sectional studies, where the timing of infection is unknown, apparent associations between infections may be observed due to parasites sharing common risk factors. This study measured antibody titres to 3 viral (Newcastle disease, Marek's disease and infectious bursal disease) and 2 bacterial (Pasteurella multocida and Salmonella) diseases, and the infection prevalence of 3 families of endo- and ecto-parasites (Ascaridida, Eimeria and lice) in 1056 village chickens from two geographically distinct populations in Ethiopia. Samples were collected during 4 cross-sectional surveys, each approximately 6 months apart. Constrained ordination, a technique for analysis of ecological community data, was used to explore this complex dataset and enabled potential relationships to be uncovered and tested despite the different measurements used for the different parasites. It was found that only a small proportion of variation in the data could be explained by the risk factors measured. Very few birds (9/1280) were found to be seropositive to Newcastle disease. Positive relationships were identified between Pasteurella and Salmonella titres; and between Marek's disease and parasitic infections, and these two groups of diseases were correlated with females and males, respectively. This may suggest differences in the way that the immune systems of male and female chickens interact with these parasites. In conclusion, we find that a number of infectious pathogens and their interactions are likely to impact village chicken health and production. Control of these infections is likely to be of importance in future development planning.  相似文献   

10.
An indirect ELISA has been developed to detect Salmonella typhimurium antibodies in chicken sera, using whole bacterial cell protein, flagellar protein or lipopolysaccharide as antigens. In experimental infections high concentrations of S typhimurium-specific IgG persisted after the faecal excretion of S typhimurium had ceased, whereas the specific IgM response was transitory. Some uninfected chickens placed in contact with experimentally infected birds developed high IgG titres in the absence of detectable faecal excretion. Other S typhimurium strains, which varied in their invasive abilities, also induced high titres of IgG. The ELISA allowed chickens infected experimentally with S typhimurium to be differentiated from chickens infected with 10 other serotypes, including S enteritidis. The use of whole blood in place of serum in the ELISA reduced the titres slightly. The storage of serum dried on to filter paper strips for four weeks produced little change in ELISA antibody titre, and the treatment of such strips with phenol or chloroform vapour had little or no effect on the antibody titre.  相似文献   

11.
THE PATHOGENESIS OF INFECTIOUS AVIAN ENCEPHALOMYELITIS   总被引：1，自引：0，他引：1  
An association was demonstrated between the development of clinical infectious avian encephalomyelitis (IAE), the persistence and titre of infectious avian encephalomyelitis virus (IAEV) in the brain of the chicken, the duration of detectable viraemia and the age of the chicken at the time of infection with the virus. The older the chicken at the time of infection the milder the disease, the lower the virus titre in the brain and the shorter the period of viraemia. IAEV serum neutralising antibody was produced earlier after infection in older chickens, and its detection was associated with decreasing virus titres in the brain and the cessation of detectable viraemia. Treatment of chickens with testosterone in ova, to inhibit the development of antibody synthesis, prevented the onset of age-associated resistance and testosterone treated birds were as susceptible to clinical IAE as baby chickens. The results suggested that the ability to produce IAEV serum neutralising antibody was an important component of age-associated resistance to IAE.  相似文献   

12.
用粪便虫卵计数（EPG）和动物体内蠕虫计数法对新疆3个不同地区的16只绵羊直肠粪便中的线虫虫卵和胃肠道线虫进行研究表明，在同一地区，绵羊直肠粪便中EPG与体内线虫荷虫量基本呈正相关；但不同季节、不同虫种的感染以及不同年龄之间卵与虫相关性的比值变化较大；粪便虫卵与体内成虫的高峰期也不完全吻合。  相似文献   

13.
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14.
不同鸡新城疫疫苗免疫鸡血清HI抗体的测定   总被引：3，自引：0，他引：3  
将试验鸡分成3个试验组和1个对照组。A组鸡接种鸡新城疫系疫苗,B组鸡接种油乳剂灭活苗,C组鸡接种鸡新城疫系疫苗,并在接种疫苗后第3、4、5、6、7、9、11、13、15、20、25d采取各组鸡血并分离血清,检测HI抗体。结果表明,接种系疫苗的组,HI抗体效价均值从4.67log2上升到10log2,接种后第5d开始上升,接种后第11d达到峰值,持续6d保持高滴度抗体水平。接种系疫苗的组,HI抗体效价均值从4.67log2上升到7log2,接种后第4d开始上升,接种后第9d达到峰值。接种油乳剂灭活苗的组,HI抗体效价均值从4.67log2上升到9.33log2,接种后第5d开始上升,接种后第11d达到峰值,持续16d保持高滴度抗体水平。系疫苗HI抗体效价上升快,效价高,较适合于紧急接种,油乳剂灭活苗HI抗体效价可在高水平维持较长时间,较适合于预防接种。  相似文献   

15.
Mannose-binding lectin (MBL) is a key protein in innate immunity. MBL binds to carbohydrates on the surface of pathogens, where it initiates complement activation via the lectin-dependent pathway or facilitates opsonophagocytosis. In vitro studies have shown that human MBL is able to bind to Salmonella, but knowledge in relation to chicken MBL and Salmonella is lacking. In order to study this relation day-old chickens from two selected lines L10H and L10L, differing in MBL serum concentration, were either orally infected with S. Infantis (S.123443) or kept as non-infected controls. The differences between healthy L10H and L10L chicken sublines were more profound than differences caused by the S. Infantis infection. The average daily body weight was higher for L10H than for L10L, regardless of infection, indicating beneficial effects of MBL selection on growth. Salmonella was detected in cloacal swabs and the number of Salmonella positive chickens during the experiment was significantly higher in L10L than L10H, indicating that MBL may affect the magnitude of Salmonella colonisation in day-old chickens. MBL expression was determined in ceca tissue by real-time RT-PCR. L10H chickens showed a significantly higher relative expression than L10L at days 1 and 41 pi, regardless of infection. Finally, flow cytometric analysis of whole blood from infected chickens showed that L10H had a significantly higher count of all assessed leucocyte subsets on day 5 pi, and also a higher count of monocytes on day 12 pi than L10L. No difference was observed between infected and non-infected L10L chicken.  相似文献   

16.
The effect of the inoculation dose on the development of antibodies as measured by the indirect fluorescent antibody (IFA) test against E. maxima and E. acervulina was studied in two experiments in each of which six groups of six chickens each were inoculated with varying numbers of oocysts.The IFA titres reached their maximum 2 weeks after inoculation. The response was dose related for both species. This response was more pronounced in the infections with E. acervulina than in those with E. maxima, reflecting a difference in immunogenicity.Reinoculation with E. maxima indicated that the birds were immune and resulted in a rise of the titres. The maximum IFA titres obtained during the primary infection were never reached by reinfection. The titres decreased gradually during the 7 weeks following reinoculation. Reinoculation with E. acervulnia resulted in higher titres than those obtained during the first infection.  相似文献   

17.
Besides infection in humans, Salmonella enteritidis can also cause serious illness in young chickens. However, the genetic and immunological parameters important for the disease in chickens are not well characterized. In this study, processes in the chicken intestine in response to a Salmonella infection were investigated in two different chicken lines. One-day-old chickens were orally infected with Salmonella. T-cell subpopulations, phagocytic properties of intestinal mononuclear cells and RNA expression levels of the jejunum were investigated. The two chicken lines differed in the amount of cfu in the liver and growth retardation after the infection. Differences in phagocytic activity of intestinal mononuclear cells were found between control and Salmonella infected chickens. The number of CD4+ T-cells of the intestine decreased after the Salmonella infection in one chicken line, while the number of CD8+ T-cells increased in both chicken lines, but the time post infection of this increase differed between the lines. In one chicken line the expression levels of the genes carboxypeptidase M and similar to ORF2 decreased after the Salmonella infection, which might be related to a decrease in the amount of macrophages. With the microarray, ten genes were found that were regulated in only one of the chicken lines, while we found six genes regulated in response to the infection in both chicken lines. So differences in genetic background of the chickens influence the intestinal host response of the Salmonella infection as observed by phagocytic activity, gene expression and changes in the number of T-cell subpopulations and macrophages.  相似文献   

18.
1. A cross-sectional study was conducted from September 2015 to July 2016 in South Tyrol, Northern Italy to examine the prevalence of gastrointestinal helminths in free-range laying hens under mountain farming production conditions.

2. A total of 280 laying hens from 14 free-range mountain farms (4 organic, 10 conventional) were randomly collected at the end of the laying period. Faecal samples were taken to analyse faecal egg counts (FEC) and faecal oocyst counts (FOC). The gastrointestinal tracts were removed post mortem and examined for the presence of helminths.

3. In faeces, FEC values averaged 258 eggs per g of faeces, which were dominated by Ascaridia galli and Heterakis gallinarum. Mean FOC was 80 oocysts/g. In the gastrointestinal tract, at least one nematode species was found in 99.3% of the examined hens. H. gallinarum was the most prevalent nematode (95.7%), followed by Capillaria spp. (66.8%) and A. galli (63.6%). Thirty per cent of the chickens were infected with cestodes (tapeworms). Correlation coefficients between worm counts of H. gallinarum, Capillaria spp. and A. galli ranged from 0.41 to 0.51.

5. The helminth prevalence did not differ between conventional and organic farms, whereas total worm burden was higher in organic compared with conventional farms (318.9 vs. 112.0). Prevalence and infection intensity did not differ between farms that used anthelmintic treatments and those that did not.

6. In conclusion, free-range laying hens under the studied mountain farming conditions are at high risk of nematode infection, especially in organic systems. The vast majority of hens are subclinical infected with at least one helminth species.  相似文献   


19.
Avian intestinal spirochaetosis (AIS) is a disease complex affecting adult laying and breeding chickens associated with infection by anaerobic intestinal spirochaetes of the genus Brachyspira. Options for control of AIS are limited, as few effective antimicrobial agents are registered for use in laying chickens. One of the two most commonly encountered pathogenic species in AIS is B. intermedia, and the aim of the current study was to determine whether a B. intermedia bacterin vaccine would help control AIS caused by this species. An autogenous bacterin was prepared from B. intermedia strain HB60 and given twice intramuscularly at a 3-week interval to 12 laying chickens housed in individual cages. Twelve non-vaccinated control chickens were placed in adjacent cages in the same room. Two weeks after the second vaccination all the chickens were experimentally challenged with B. intermedia HB60 by crop tube. Subsequently faeces were cultured for spirochaetes every 2-3 days, faecal water content and chicken weight were measured weekly, and egg numbers and weights were recorded daily. Serum was taken prior to both vaccinations, at the time of challenge and at euthanasia. The chickens were killed 6 weeks post-challenge. The vaccinated chickens showed seroconversion to the vaccine, but antibody levels declined significantly post-infection. In comparison, the non-vaccinated chickens showed seroconversion post-infection. The reason for the reduction in the antibody levels in the vaccinated chickens after infection was not explained. At some point all the chickens excreted spirochaetes in their faeces, and the duration of excretion was not different between vaccinated and non-vaccinated chickens. There were no differences in faecal water content, chicken weights, egg production, or gross and microscopic caecal lesions between vaccinated and non-vaccinated chickens. In conclusion, an autogenous bacterin vaccine did not prevent infection with B. intermedia in laying chickens.  相似文献   

20.
A total of 291 eight-week-old chickens were exposed to chickens infected with either of two Australian lentogenic strains (V4 and AVL NDV-1) of Newcastle disease virus (NDV). At 3 weeks after exposure, all chickens exposed to V4 infected chickens had developed haemagglutination-inhibition (HI) antibody. All chickens exposed to AVL NDV-1 virus infected chickens had developed HI antibody 5 weeks later. This sudden late appearance of HI antibody, to titres higher than those observed with V4 chickens, was explained by V4 virus being introduced to the AVL NDV-1 group of chickens. When groups of these chickens were challenged with Roakin virus (mesogenic NDV) at 3 weeks and Fontana 1083 virus (viscerotropic velogenic NDV) and Texas GB virus (neutrotropic NDV) at 3, 5, 10 and 21 weeks only three chickens developed clinical illness one of which died. These chickens were one AVL NDV-1 chicken contact challenged with Fontana 1083 virus at 3 weeks, one V4 chicken oronasally challenged with Texas GB virus at 5 weeks and one V4 chicken challenged oronasally with Fontana 1083 virus at 10 weeks. Susceptible non-vaccinated chickens died soon after challenge. Challenge by oronasal infection with 10(7.0) ELD50 of virus or contact with susceptible infected chickens enabled virulent virus to be isolated from most chickens and was accompanied by a large anamnestic increase in serum HI antibody.  相似文献   

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