Detection of antibodies to the nonstructural protein (NS1) of avian influenza viruses allows distinction between vaccinated and infected chickens

To differentiate avian influenza virus (AIV)-infected chickens vs. chickens immunized with inactivated avian influenza virus, an enzyme-linked immunosorbent assay (ELISA) was developed using a recombinant nonstructural protein (NS1) as the diagnostic antigen, which was cloned from an AIV H9N2 subtype strain isolated during the avian influenza outbreak of 2003-04 and expressed in Escherichia coli. Antibodies to the AIV NS1 protein was only detected in the sera of chickens experimentally infected with AIV but not in the sera of chickens immunized with inactivated vaccine. This ELISA is useful for serological diagnosis to distinguish chickens infected with influenza viruses from those immunized with inactivated vaccine.     

Development of Indirect Enzyme-linked Immunosorbent Assay with Nucleoprotein as Antigen for Detection and Quantification of Antibodies against Avian Influenza Virus

Avian influenza (AI) is a serious infectious disease caused by avian influenza virus (AIV) belonging to type A Orthomyxovirus. In the present study, we developed an indirect enzyme-linked immunosorbent assay (ELISA) employing E. coli-expressed full-length nucleoprotein (NP) of H9N2 avian influenza virus for the detection and quantification of antibodies against AIV nucleoprotein. The NP-ELISA was compared with the AI agar gel propagation (AGP) test, haemagglutination inhibition (HI) test, and IDEXX-FlockChek ELISA using 263 sera. The NP-ELISA was significantly more sensitive than the AGP and HI tests, and showed 96.2% agreement ratio with IDEXX-FlockChek ELISA. With results obtained using the NP-ELISA, an ELISA titre (ET) prediction equation, with which the ELISA titres of a flock or individual chickens can be determined, was derived from a positive/negative (P/N) ratio standard curve. The NP-ELISA enables an alternative rapid serological diagnosis and is suitable for influenza A antibody screening, especially in species that harbour several influenza subtypes.     

Development and preliminary application of an indirect ELISA for detecting antibodies against Avian Influenza Virus

Fragment of 759 bp DNA spanning the Matrix 1 (M1) gene of Avian Influenza Virus (AIV) was inserted into an expression vector pET28c to construct a recombinant plasmid pET28c-M1. The pET28c-M1 plasmid was transformed into the Escherichia coli BL21 (DE3) competent cell to produce a recombinant strain E. coli 21 (DE3). After being induced by Isopropyl-b-D-galactopyranoside (IPTG), E. coli 21 (DE3) expressed a 28-kDa fusion protein at a high level. This protein can bind anti-AIV (H5N1) positive serum by Western-blot analysis. After being denatured, renatured, and purified by Ni(2+)-column, the fusion protein was used as an antigen to develop Matrix 1 Enzyme-Linked Immunosorbent Assay (M1-ELISA) for detecting antibodies against AIV from chicken serum. We found that this indirect M1-ELISA was sensitive for differentiating antisera against AIV and antisera against other six kinds of avian viruses apart from AIV and this method is more sensitive than Hemagglutination Inhibition (HI) test. When compared with HI test and ELISA (IDEXX) in evaluating 581 serum samples from field vaccinated chickens, this assay showed 93.3% agreement ratio with the HI test, as well as 96.0% agreement ratio with ELISA (IDEXX). In a preliminary application, the assay successfully detected 19 AIVs from 51 nonvaccinated chicken lungs. It concludes that an indirect ELISA was successfully developed for detecting AIV. The assay is specific and sensitive. The application will greatly contribute to the long-term prevention and control of avian influenza in China.     

Development of an enzyme-linked immunosorbent assay for detecting infectious bursal disease virus (IBDV) infection based on the VP3 structural protein

Infectious bursal disease virus (IBDV) causes a contagious immunosuppressive disease in chickens. The aim of the present study is to develop an enzyme-linked immunosorbent assay (ELISA) using the expressed VP2 or VP3 protein of IBDV as the coating antigen for detecting antibodies to IBDV. Experimental results were compared with virus neutralization assay and a commercial-available ELISA. These assays were used to examine the sera from farm chickens and chickens vaccinated experimentally. The VP3-based ELISA had a higher correlation coefficient (R(2)) of 0.812 with a commercial ELISA kit at a serum dilution of 1:500 than that of VP2-based ELISA (R(2)) of 0.671. The relative sensitivity between virus neutralization and VP2-ELISA and VP3-ELISA was 96% (251/262) and 100% (262/262), respectively, and that between virus neutralization and a commercial ELISA was 99% (257/261). Additionally, compared with virus neutralization assay, the reference technique for diagnosing IBDV, VP3-based ELISA had an agreement value of 99%, superior to that of VP2-based ELISA (95%) or the commercial kit (89%). These results revealed that the capability of either VP2-ELISA or VP3-ELISA in detecting the field chicken sera was comparable to the commercial one, which is generally used to replace the virus neutralization assay. However, the preparation of VP3 is derived from an Escherichia coli expression system with a high yield and purification efficiency by Ni(2+)-NTA gels, which is more favorable to the insect cell-derived particles formed by VP2. Therefore, VP3-ELISA could be developed as an efficient and low cost diagnostic method for IBDV infection in field chickens.     

Investigation of H7N2 avian influenza outbreaks in two broiler breeder flocks in Pennsylvania, 2001-02

An avian influenza (AI) outbreak occurred in meat-type chickens in central Pennsylvania from December 2001 to January 2002. Two broiler breeder flocks were initially infected almost simultaneously in early December. Avian influenza virus (AIV), H7N2 subtype, was isolated from the two premises in our laboratory. The H7N2 isolates were characterized as a low pathogenic strain at the National Veterinary Services Laboratories based on molecular sequencing of the virus hemagglutinin cleavage site and virus challenge studies in specific-pathogen-free leghorn chickens. However, clinical observations and pathologic findings indicated that this H7N2 virus appeared to be significantly pathogenic in meat-type chickens under field conditions. Follow-up investigation indicated that this H7N2 virus spread rapidly within each flock. Within 7 days of the recognized start of the outbreak, over 90% seroconversion was observed in the birds by the hemagglutination inhibition test. A diagnosis of AI was made within 24 hr of bird submission during this outbreak using a combination of virus detection by a same-day dot-enzyme-linked immunosorbent assay and virus isolation in embryonating chicken eggs. Follow-up investigation revealed that heavy virus shedding (90%-100% of birds shedding AIV) occurred between 4 and 7 days after disease onset, and a few birds (15%) continued to shed virus at 13 days post-disease onset, as detected by virus isolation on tracheal and cloacal swabs. AIV was not detected in or on eggs laid by the breeders during the testing phase of the outbreak. The two flocks were depopulated at 14 days after disease onset, and AIV was not detected on the two premises 23 days after depopulation.     

检测禽流感病毒抗体的重组核蛋白间接ELISA方法的建立

以大肠杆菌系统表达的H9N2亚型禽流感病毒（AIV）核蛋白（NP）为抗原，建立了禽流感间接酶联免疫吸附试验抗体检测技术（NP—ELISA）。对263份待检血清（包括临床收集的243份血清和20份H9N2亚型AIV免疫鸡阳性血清）进行检测，NP—ELISA与琼脂免疫扩散试验（AGP）的总符合率为83．3％，与血凝抑制试验（HI）的总符合率为92％。特异性试验表明，NP—ELISA方法可以检测H5、H7和H9亚型AIV特异性抗体，检测为阳性的血清样品能够被阳性鸡胚尿囊液阻断。敏感性试验证实，NP—ELISA最早可以检测鸡感染后7d的血清样品，并于感染后10d确定100％血清阳性，而AGP检测直到首免后21～28d才出现部分血清阳性，HI检测直到10～14d才出现部分血清阳性，并且NP-ELISA要比HI敏感4～40倍。试验证明，NP—ELISA是检测AIV血清型特异性抗体的一种特异、敏感、快速、经济的血清学检测技术。     

Failure of a recombinant fowl poxvirus vaccine containing an avian influenza hemagglutinin gene to provide consistent protection against influenza in chickens preimmunized with a fowl pox vaccine

Vaccines against mildly pathogenic avian influenza (AI) have been used in turkeys within the United States as part of a comprehensive control strategy. Recently, AI vaccines have been used in control programs against highly pathogenic (HP) AI of chickens in Pakistan and Mexico. A recombinant fowl pox-AI hemagglutinin subtype (H) 5 gene insert vaccine has been shown to protect specific-pathogen-free chickens from HP H5 AI virus (AIV) challenge and has been licensed by the USDA for emergency use. The ability of the recombinant fowl pox vaccine to protect chickens preimmunized against fowl pox is unknown. In the current study, broiler breeders (BB) and white leghorn (WL) pullets vaccinated with a control fowl poxvirus vaccine (FP-C) and/or a recombinant fowl poxvirus vaccine containing an H5 hemagglutinin gene insert (FP-HA) were challenged with a HP H5N2 AIV isolated from chickens in Mexico. When used alone, the FP-HA vaccine protected BB and WL chickens from lethal challenge, but when given as a secondary vaccine after a primary FP-C immunization, protection against a HP AIV challenge was inconsistent. Both vaccines protected against virulent fowl pox challenge. This lack of consistent protection against HPAI may limit use to chickens without previous fowl pox vaccinations. In addition, prior exposure to field fowl poxvirus could be expected to limit protection induced by this vaccine.     

H5 antibody detection by blocking enzyme-linked immunosorbent assay using a monoclonal antibody

Many commercial enzyme-linked immunosorbent assays (ELISAs) are unable to differentiate antibody responses to different avian influenza virus (AIV) subtypes. Developing an ELISA for specifically detecting the H5 antibody is the purpose of this study. Four monoclonal antibodies (Mabs) were raised using A/duck/Yunlin/04 (H5N2). They were confirmed as being specific to H5. Two of these antibodies showed hemagglutination inhibition (HI) activity using the HI test. Using immunodot blot assays, three Mabs recognized both Eurasian and American H5, whereas the other Mab recognized only the tested Eurasian H5 virus. When testing denatured H5 antigen, one of the Mabs lost its antigen binding activity using Western blotting. For detecting the H5 humoral response in serum, one monoclonal antibody was purified and labeled with horseradish peroxidase to set up a blocking ELISA. Chicken sera that blocked H5 Mab binding by > 29% were considered H5 antibody positive. Inhibition percentages for sera from chickens infected with other AIV subtypes, H1 to H15, were < 29%. This blocking ELISA was used for 478 field chicken serum samples. The results showed that the sensitivity and specificity of this ELISA were 98.3% (232/236) and 95.9% (232/242), respectively. This blocking ELISA could be used specifically for detecting the H5 humoral responses in chickens.     

Evaluation of a competitive ELISA for antibody detection against avian influenza virus

Active serologic surveillance is necessary to control the spread of the avian influenza virus (AIV). In this study, we evaluated a commercially-available cELISA in terms of its ability to detect AIV antibodies in the sera of 3,358 animals from twelve species. cELISA detected antibodies against reference H1- through H15-subtype AIV strains without cross reactivity. Furthermore, the cELISA was able to detect antibodies produced following a challenge of the AIV H9N2 subtype in chickens, or following vaccination of the AIV H9 or H5 subtypes in chickens, ducks and geese. Next, we tested the sensitivity and specificity of the cELISA with sera from twelve different animal species, and compared these results with those obtained by the hemagglutination-inhibition (HI) test, the "gold standard" in AIV sera surveillance, a second commercially-available cELISA (IZS ELISA), or the agar gel precipitation (AGP) test. Compared with the HI test, the sensitivities and specificities of cELISA were 95% and 96% in chicken, 86% and 88% in duck, 97% and 100% in turkey, 100% and 87% in goose, and 91% and 97% in swine, respectively. The sensitivities and specificities of the cELISA in this study were higher than those of IZS ELISA for the duck, turkey, goose, and grey partridge sera samples. The results of AGP test against duck and turkey sera also showed significant correlation with the results of cELISA (R-value >0.9). In terms of flock sensitivity, the cELISA correlated better with the HI test than with commercially-available indirect ELISAs, with 100% flock sensitivity.     

Improvements to the hemagglutination inhibition test for serological assessment of recombinant fowlpox-H5-avian-influenza vaccination in chickens and its use along with an agar gel immunodiffusion test for differentiating infected from noninfected vaccinated animals

In general, avian influenza (AI) vaccines protect chickens from morbidity and mortality and reduce, but do not completely prevent, replication of wild AI viruses in the respiratory and intestinal tracts of vaccinated chickens. Therefore, surveillance programs based on serological testing must be developed to differentiate vaccinated flocks infected with wild strains of AI virus from noninfected vaccinated flocks in order to evaluate the success of vaccination in a control program and allow continuation of national and international commerce of poultry and poultry products. In this study, chickens were immunized with a commercial recombinant fowlpox virus vaccine containing an H5 hemagglutinin gene from A/turkey/Ireland/83 (H5N8) avian influenza (AI) virus (rFP-H5) and evaluated for correlation of immunological response by hemagglutination inhibition (HI) or agar gel immunodiffusion (AGID) tests and determination of protection following challenge with a high pathogenicity AI (HPAI) virus. In two different trials, chickens immunized with the rFP-H5 vaccine did not develop AGID antibodies because the vaccine lacks AI nucleoprotein and matrix genes, but 0%-100% had HI antibodies, depending on the AI virus strain used in the HI test, the HI antigen inactivation procedure, and whether the birds had been preimmunized against fowlpox virus. The most consistent and highest HI titers were observed when using A/turkey/Ireland/83 (H5N8) HPAI virus strain as the beta-propiolactone (BPL)-inactivated HI test antigen, which matched the hemagglutinin gene insert in the rFP-H5 vaccine. In addition, higher HI titers were observed if ether or a combination of ether and BPL-inactivated virus was used in place of the BPL-inactivated virus. The rFP-H5 vaccinated chickens survived HPAI challenge and antibodies were detected by both AGID and HI tests. In conclusion, we demonstrated that the rFP-H5 vaccine allowed easy serological differentiation of infected from noninfected birds in vaccinated populations of chickens when using standard AGID and HI tests.     

A longitudinal study of a novel dot-enzyme-linked immunosorbent assay for detection of avian influenza virus

A monoclonal antibody (MAb)-based dot-enzyme-linked immunosorbent assay (ELISA) has been developed that detected the epitopes specifically associated with avian influenza virus (AIV). The dot-ELISA detected the antigens of AIV directly from clinical and field specimens. Data obtained from experimentally AIV-infected specific-pathogen-free chickens and also the 2001/02 AIV outbreak of serotype H7N2 positive flocks in Pennsylvania indicated that the mean sensitivity (Se) of the dot-ELISA ranged between 45% and 68% and the mean specificity (Sp), between 85% and 90%. The values were derived from various clinical and field specimens when compared with virus isolation with embryonating chicken eggs. On routine AIV surveillance samples, the dot-ELISA achieved a 92%-100% Sp on the basis of resting over 1500 AIV surveillance samples that were confirmed negative by virus isolation. The dot-ELISA detected AIV antigens with a 5-microl allantoic fluid sample that contained a concentration of 0.4 hemagglutinating units. Furthermore, the dot-ELISA retained its specificity for AIV because no cross-reactions were obtained with various other avian viruses. The findings in this study indicated that the dot-ELISA was highly sensitive and specific and comparable with the commercial Directigen test in the detection of AIV obtained from clinical and field specimens.     

Risk factors for the introduction of avian influenza virus into commercial layer chicken farms during the outbreaks caused by a low-pathogenic H5N2 virus in Japan in 2005

Avian influenza outbreaks caused by a low-pathogenic H5N2 virus occurred in Japan from June to December 2005. All 41 affected farms housed layer chickens. Therefore, we conducted a case-control study targeting all commercial layer chicken farms within the movement restriction areas in Ibaraki prefecture, where most outbreaks were detected, to investigate the risk factors for the introduction of avian influenza virus (AIV). Four variables were identified as risk factors associated with the introduction of AIV by multivariate logistic regression: 'introduction of end-of-lay chickens ' (odds ratio (OR) = 36.6), 'sharing of farm equipment among farms' (OR = 29.4), 'incomplete hygiene measures of farm visitors on shoes, clothes and hands' (OR = 7.0), and 'direct distance to the nearest case farm' (0-500 m, OR = 8.6; 500-1000 m, OR = 0.8; 1000-1500 m, OR = 20.1; referenced more than 1500 m). We fully believe that strict biosecurity measures should be applied against any incursion points so as not to introduce AIV into more farms.     

Development and evaluation of a DAS-ELISA for rapid detection of avian influenza viruses

Rapid detection of avian influenza virus (AIV) infection is critical for control of avian influenza (AI) and for reducing the risk of pandemic human influenza. A double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) was developed for this purpose. The method employed a monoclonal antibody (MAb) as the capture antibody and rabbit polyclonal IgG labeled with horseradish peroxidase as the detector antibody, and both antibodies were against type-specific influenza A nucleoprotein (NP). The DAS-ELISA could detect minimally 2.5 ng of influenza viral protein in virus preparations treated with Triton X-100, which is equvilent to 2.5 x 10(2) EID50 virus particles. This DAS-ELISA could detect all 15n AIV subtypes (H1-H15) and did not cross react with other avian pathogens tested. The DAS-ELISA were directly compared with virus isolation (VI) in embryonated chicken eggs, the current standard of influenza virus detection, for 805 chicken samples. The DAS-ELISA results correlated with VI results for 98.6% of these samples, indicating a sensitivity of 97.4% and specificity of 100%. The method was further tested with H5N1 and H9N2 AIV experimentally infected chickens, ducks, and pigeons, as well as field samples obtained from central China in 2005. The DAS-ELISA method has demonstrated application potential as an AIV screening tool and as a supplement for virus isolation in Asia.     

Efficacy of vaccines in chickens against highly pathogenic Hong Kong H5N1 avian influenza.

In 1997, highly pathogenic (HP) H5N1 avian influenza virus (AIV) caused infections in poultry in Hong Kong and crossed into humans, resulting in a limited number of infections including 18 hospitalized cases and six associated deaths. The unique ability of this, AIV to infect both poultry and people raised a concern for the potential of humans to be biological as well as mechanical vectors of this AIV to poultry. The current study was undertaken to determine if existing vaccines and their technologies could be used during an outbreak to protect poultry. Commercial and experimental inactivated whole H5 AIV and baculovirus-expressed AIV H5 hemagglurinin protein vaccines provided protection from clinical signs and death in chickens after lethal challenge by human-origin HP H5N1 Hong Kong strains 156/97 and 483/97. The commercial and experimental inactivated vaccines had mean protective doses ranging from 0.25 to 0.89, which represents the milligrams of viral protein in the vaccines that provided protection from death in half of the birds. Furthermore, the vaccines reduced the ability of the challenge AIV to replicate in chickens and decreased the recovery of challenge AIV from the enteric and respiratory tracts, but the use of a vaccine will nor totally prevent AI virus replication and shedding. Existing vaccines will protect poultry from mortality and reduce virus replication from the new HP AIV strain that can infect both poultry and humans.     

鸡新城疫病毒的分离与鉴定

从山东某鸡场的产蛋下降而无其他典型新城疫(Newcastle Disease)症状的高抗体蛋鸡群中分离到一株病毒。经过试验鉴定,该分离株具有血凝性,且可被ND标准阳性血清所抑制和中和,不能被AI(H5亚型与H9亚型)标准阳性血清抑制;该病毒的最小致死量病毒致死鸡胚的平均时间(h)为50.4 h,1日龄SPF鸡脑内接种分离病毒致病指数(ICPI)为1.85,6周龄SPF鸡静脉接种致病指数(IVPI)为2.42,回归试验鸡出现了新城疫症状和病变,经外源病毒检测及回归试验该病毒株被确定为新城疫病毒,并属强毒型,命名为ShD-5-04。     

Evaluation of the protective efficacy of a commercial vaccine against different antigenic groups of H9N2 influenza viruses in chickens

Despite the long-term vaccination programs implemented in China, H9N2 avian influenza viruses (AIVs) continue to persist in chicken populations, even in vaccinated flocks. We previously demonstrated that H9N2 AIV isolated from chickens in China also underwent antigenic drift and evolved into distinct antigenic groups (C, D and E). To understand whether antigenic drift of viruses away from the vaccine strain partially contributed to the circulation of H9N2 AIV in China, we evaluated the protective efficacy of a commercial vaccine against different antigenic groups of H9N2 AIV. Challenge experiments using vaccinated chickens indicated that the vaccine prevented shedding of antigenic group C viruses, but not those of the more recent groups D and E. Vaccinated chickens, even those with vaccine-induced HI titers of 1:1024, shed virus after being infected with A/chicken/Shandong/ZB/2007, a representative virus of antigenic group D. Genetic analysis showed that the representative viruses of antigenic groups D and E possessed greater numbers of amino acid substitutions in the hemagglutinin protein compared to the vaccine strain and the antigenic group C virus, and many of which were located in antigenic sites. Our results indicated that the persistence of H9N2 AIV in China might be due to incomplete vaccine protection, and that the avian influenza vaccine should be regularly evaluated and updated to maintain optimal protection. Furthermore, the avian influenza vaccination policy also needs to be re-assessed, and increased veterinary biosecurity on farms, rather than vaccine application alone, should be implemented to prevent and control avian influenza.     

应用多重引物RT-PCR快速诊断禽流感亚型

将本实验室分离保存、已经过PCR扩增、核酸测序鉴定的三种不同亚型禽流感病毒(AIVH5N1、H6N2、H9N2)分别接种鸡胚,收集尿囊液,分离提取AIV总RNA。参考H1￣H15亚型禽流感病毒的核蛋白(NP)基因序列以及H5、H6、H9亚型AIV血凝素(HA)基因序列,设计四对引物:NP1,NP2;H5P1,H5P2;H6P1,H6P2;H9P1,H9P2,混合为PCR扩增多重引物MP1,下游引物NP2、H5P2、H6P2,、H9P2混合为逆转录反应多重引物MP2。AIV总RNA在相同反应条件下经MP2逆转录,用MP1进行PCR扩增,AIVH5亚型材料得到205bp,563bp两条扩增带,AIVH6亚型材料得到205bp,233bp两条扩增带,AIVH9亚型材料得到205bp,690bp两条扩增带,都与实验设计相符合,阴性材料没有扩增带。该方法成功实现四对引物进行RT-PCR反应同时检测出AIV,准确诊断H5、H6、H9三种禽流感亚型,检测时间短,特异性强,能及时检测出AIV亚型。     

Development of a specific latex agglutination test based on a recombinant hemagglutinin protein to detect antibodies to H5 avian influenza viruses

A latex agglutination test (LAT) was developed for rapid detection of antibodies to H5 avian influenza viruses (AIVs). The hemagglutinin protein of H5 AIV was covalently linked to carboxylated latex by ethyl-dimethyl-amino-propyl carbodiimide to prepare the sensitized latex beads. The LAT was evaluated with the hemagglutination inhibition (HI) assay as the reference test. The H5-LAT showed a sensitivity of 87.0% and specificity of 88.9% in detecting 126 serum samples from experimentally infected chickens and a sensitivity of 82.5% and specificity of 86% in detecting 587 field chicken serum samples from mostly vaccinated chickens. The agreement ratio between H5-LAT and HI was found to be 87.3% and 83.1% for the two groups of samples, respectively. Difficulty with background agglutination in stored chicken sera was overcome by serum pretreatment with either dried chicken liver powder or dilution buffer containing detergent Tween-20. The H5-LAT has advantages over a previously reported whole-virus LAT in terms of biosafety in preparation, chemical stability, and higher specificity. It is a rapid and simple test suitable for field monitoring of antibodies to H5-type AIV.     

禽呼肠孤病毒σNS和P17非结构蛋白作为ELISA鉴别诊断抗原的研究

表达并纯化了禽呼肠孤病毒(ARV)的2个非结构蛋白σNS和P17,并以此作为包被用抗原,分别进行间接ELISA。结果表明,抗原最佳包被浓度分别为9.3μg/mL和11.5μg/mL;一抗血清的稀释度都是1∶200;HRP酶标二抗羊抗鸡IgG稀释度为1∶5 000,初步建立了能检测ARV感染的σNS-ELISA、P17-ELISA方法。以σNS、P17两种蛋白按以上确定的条件同时包被,建立了σNS-P17-ELISA。分别用σNS-ELISA、P17-ELISA及σNS-P17-ELISA对接种过ARV活病毒或灭活疫苗的33份SPF鸡血清进行检测,结果发现以非结构蛋白建立的3种ELISA方法均能区分ARV活病毒感染与灭活疫苗免疫的抗体,进一步对这3种方法进行敏感性、特异性分析比较,表明σNS-P17-ELISA方法能更有效地区分ARV感染与灭活疫苗免疫抗体。     

H5亚型禽流感病毒间接免疫荧光快速诊断方法的建立

本研究以当前严重威胁我国养禽业的高致病性禽流感H5亚型病毒为研究对象，病毒在犬肾细胞（MDCK）上培养增殖，经蔗糖梯度离心对病毒进行纯化，免疫清洁级的新西兰公兔，高免血清经辛酸-硫酸铵法和葡聚糖G50柱纯化，制得第一抗体。以FITC标记的山羊抗兔IgG为第二抗体，通过反应条件的优化，建立了间接免疫荧光快速诊断方法。本法的最佳检测组织为心肌和胰腺，检测时间只需3小时，本法可检出人工感染后36小时尚未表现出临床症状鸡只中的病毒，对禽流感H7亚型、H9亚型病、新城疫、传染性支气管炎和传染性喉气管炎禽出败等病料进行特异性检验结果均为阴性。运用本方法对69个禽场的临床病料进行了检测，检测结果与鸡胚分离法进行比对，9个阳性场（广东省2004年9个原疫点的病料）的9份病料中，检出8份阳性；而鸡胚分离法阴性样品，本法检测结果与之完全相符。本法用于禽流感H5亚型病毒的快速诊断具有快速、简便、敏感、特异、费用低廉和不存在交叉污染等优点，在当前流行的H5亚型高致病性禽流感快速诊断中具有良好的应用前景。