Rapid Antigen Detection Kits Research Articles

Misdiagnosis of SARS-CoV-2: A Critical Review of the Influence of Sampling and Clinical Detection Methods.

SARS-CoV-2 infection has generated the biggest pandemic since the influenza outbreak of 1918–1919. One clear difference between these pandemics has been the ability to test for the presence of the virus or for evidence of infection. This review examined the performance characteristics of sample types via PCR detection of the virus, of antibody testing, of rapid viral antigen detection kits and computerised tomography (CT) scanning. It was found that combined detection approaches, such as the incorporation of CT scans, may reduce the levels of false negatives obtained by PCR detection in both symptomatic and asymptomatic patients, while sputum and oral throat washing sample types should take precedence over swabbing when available. Rt-PCR assays for detection of the virus remain the gold-standard method for SARS-CoV-2 diagnosis and can be used effectively on pooled samples for widespread screening. The novel Oxford antibody assay was found to have the highest sensitivity and specificity of four currently available commercial antibody kits but should only be used during a specific timeframe post-symptom onset. Further research into transmission modes between symptomatic and asymptomatic patients is needed. Analysis of the performance characteristics of different sampling and detection methods for SARS-CoV-2 showed that timing of sampling and testing methods used can greatly influence the rate of false-positive and false-negative test results, thereby influencing viral spread.

Equine rotavirus infection

ABSTRACTThis review briefly describes the virus classification, clinical signs, epidemiology, diagnosis, disinfection, and vaccines related equine group A rotavirus (RVA) infection. Equine RVA is one of the most important pathogens causing diarrhoea in foals. The main transmission route is faecal–oral, and the clinical signs are diarrhoea, fever, lethargy, and anorexia (decreased suckling). Some human RVA rapid antigen detection kits based on the principles of the immunochromatographic assay are useful for the diagnosis of equine RVA infection. The kits are used in daily clinical practice because of their rapidity and ease of handling. Equine RVA is a non-enveloped virus and is more resistant to disinfectants than enveloped viruses such as equine influenza virus and equine herpesvirus. Although amphoteric soaps and quaternary ammonium compounds are commonly used in veterinary hygiene, they are generally ineffective against equine RVA. Alcohol products, aldehydes, and chlorine- and iodine-based compounds are effective against equine RVA. Inactivated vaccines have been used for equine RVA infection in some countries. Pregnant mares are intramuscularly inoculated with a vaccine, and thus their colostrum has abundant antibodies against RVA at the time of birth. According to G and P classification defined in accordance with the VP7 and VP4 genes, respectively, the predominant equine RVAs circulating in horse populations globally are G3P[12] and G14P[12] equine RVAs, but the vaccines contain only the G3P[12] equine RVA strain. Ideally, a G14P[12] equine RVA should be added as a vaccine strain to obtain a better vaccine effect.

Evaluation of rapid antigen detection kit from the WHO Emergency Use List for detecting SARS-CoV-2.

BackgroundCurrently, there are two rapid antigen detection (RAD) kits from the WHO Emergency Use List for detecting SARS-CoV-2.ObjectiveThe Panbio COVID-19 Ag Rapid Test Device was selected to evaluate the performance for detecting SARS-CoV-2.Study DesignAnalytical sensitivity for the detection of SARS-CoV-2 virus was determined by limit of detection (LOD) using RT-PCR as a reference method. Clinical sensitivity was evaluated by using respiratory specimens collected from confirmed COVID-19 patients.ResultsThe LOD results showed that the RAD kit was 100 fold less sensitive than RT-PCR. Clinical sensitivity of the RAD kit was 68.6 % for detecting specimens from COVID-19 patients.ConclusionsThe RAD kit evaluated in the present study shared similar performance with another kit from the WHO Emergency Use List, the Standard Q COVID-19 Ag. Understanding the clinical characteristics of RAD kits can guide us to decide different testing strategies in different settings.

Performance of the Influ a + B K-SeT® assay as compared to two RT-PCR assays for detection of influenza virus

ObjectivesTo evaluate the performance of Influ A + B K-SeT®, a rapid influenza antigen detection kit, in order to determine whether its implementation as a point-of-care test in the emergency room (ER) is justified. MethodsNasopharyngeal swabs (n = 170) were collected in triplicates from patients with suspected influenza infection. One sample was tested by the Influ A + B K-SeT® kit and the other two samples were analyzed with Simplexa™ Flu A/B & RSV Direct Kit and Xpert® Flu, two RT-PCR-based assays routinely used in the ER. ResultsThe sensitivity and specificity of the Influ A + B K-SeT® kit were 91.2%–94.5% and 98.2%, respectively, compared to the Xpert® Flu assay and the Simplexa™ Flu A/B & RSV Direct Kit, respectively. ConclusionsConsidering the satisfactory diagnostic performance of the Influ A + B K-SeT® test, its implementation as a point-of-care is expected to aid in decision-making, minimize time-to-result and reduce healthcare costs.

An Ultra-Rapid Real-Time RT-PCR Method Using PCR1100 for Detecting Human Orthopneumovirus.

Human orthopneumovirus, also known as the respiratory syncytial virus (RSV), is a leading cause of respiratory tract infections in children worldwide. The World Health Organization has taken steps toward establishing a global surveillance system for RSV, based on the global influenza surveillance and response system initiated in 2015. The US Centers for Disease Control and Prevention (CDC) has developed a genetic detection method based on real-time reverse transcription polymerase chain reaction (RT-PCR), which is used in global RSV surveillance. In Japan, immunoassay-based rapid antigen detection kits are widely used for the detection of RSV. In this study, an ultra-rapid real-time RT-PCR method for the rapid detection of RSV was developed using the PCR1100 device based on the US CDC assay in order to detect RSV in comparable time to rapid test kits. The ultra-rapid real-time RT-PCR could detect RSV viral RNA in less than 20 min while maintaining sensitivity and specificity comparable to conventional real-time RT-PCR using large installed instruments. Furthermore, combining ultra-rapid real-time RT-PCR with the M1 Sample Prep kit reduced the total working time for the detection of RSV from clinical specimen to less than 25 min, suggesting this method could be used for point-of-care RSV testing.

A study to correlate smear microscopy and rapid antigen detection techniques in the diagnosis of malaria

Introduction: Malaria is an endemic, tropical protozoan infection caused different Plasmodium species. A study was conducted to find the correlation between the peripheral blood smear and antigen demonstration for the detection of malaria. Materials and Methods: Study was conducted in the Department of Microbiology, GSL Medical College for 6 months. Peripheral blood smear stained by Giemsa technique ad commercially available rapid antigen detection kits were used for the diagnosis of malaria. Smear preparation and staining were carried as per WHO guidelines and manufacturer guidelines were followed to perform the test. Results: Among 98 the clinically diagnosed malaria cases in this study, 69 (70.4%) cases were identified as malaria positive. Out of these, 68% (47) were positive by blood smear examination and 87% (60) were positive by kit method and in the positive cases 35 were male and 34 were female participants. Conclusion: Rapid diagnostic tests were more sensitive in the diagnosis of malaria. However, other confirmatory tests such as PCR should be considered because some clinically proved cases were missed.

Comparative Efficacy of Canine Parvovirus-2 Infection Diagnostic Tests Commonly Prevailing in India

Early and rapid field diagnosis of CPV-2 infection is essential for preventing disease transmission from infected to susceptible dogs. In the present study total 91 fecal samples and rectal swabs collected from a diarrheic and non-diarrheic dog from clinics located in and around Nagpur. Polymerase Chain Reaction Rapid Antigen detection kit, and Haemagglutination test (HA) were able to detect CPV-2 in 41 (45.05%), 34 (37.36%) and 22 (24.17%) samples, respectively. The evaluation revealed that the PCR method was found to be most sensitive followed by antigen detection kit and HA field test. Sensitivity and specificity of antigen detection kit with respect to PCR method were found to be 78.08% and 96.00%, respectively. The finding suggests PCR with the highest sensitivity may be taken as a gold standard test of CPV-2 relative to other diagnostic tests. HA test could be employed for the preliminary screening in field because of its rapid response and low cost.

Whole-genome sequencing and antigenic analysis of the first equine influenza virus identified in Turkey.

BackgroundIn 2013, there was an outbreak of acute respiratory disease in racehorses in Turkey. The clinical signs were consistent with equine influenza (EI).ObjectiveThe aim was to confirm the cause of the outbreak and characterise the causal virus.MethodsA pan‐reactive influenza type A real‐time RT‐PCR and a rapid antigen detection kit were used for confirmatory diagnosis of equine influenza virus (EIV). Immunological susceptibility to EIV was examined using single radial haemolysis and ELISA. Antigenic characterisation was completed by haemagglutinin inhibition using a panel of specific ferret antisera. Genetic characterisation was achieved by whole‐genome sequencing using segment‐specific primers with M13 tags.ResultsA H3N8 EIV of the Florida clade 2 sublineage (FC2) was confirmed as the causal agent. The index cases were unvaccinated and immunologically susceptible. Phylogenetic analysis of the HA1 and NA genes demonstrated that A/equine/Ankara/1/2013 clustered with the FC2 strains circulating in Europe. Antigenic characterisation confirmed the FC2 classification and demonstrated the absence of significant drift. Whole‐genome sequencing indicated that A/equine/Ankara/1/2013 is most closely related to the viruses described as the 179 group based on the substitution I179V in HA1, for example A/equine/East Renfrewshire/2/2011, A/equine/Cambremer/1/2012 and A/equine/Saone et Loire/1/2015. The greatest diversity was observed in the NS1 segment and the polymerase complex.ConclusionsThe first recorded outbreak of EI in Turkey was caused by an FC2 virus closely related to viruses circulating in Europe. Antigenic and genetic characterisation gave no indication that the current OIE recommendations for EI vaccine composition require modification.

Assessment of a Rapid Antigen Detection Kit for Diagnosis of <i>Mycoplasma pneumoniae</i> in Pediatric Community-Acquired Pneumonia

肺炎マイコプラズマ（Mp）抗原検出による迅速診断キット（リボテストⓇマイコプラズマ（以下リボテスト）：旭化成ファーマ）の有用性には一定の見解がない。2014年1月1日～2016年3月31日に当センターに肺炎で入院した小児を対象とし，入院時，咽頭拭い液からloop-mediated isothermal amplification（LAMP）法およびリボテストを施行し，また入・退院時のペア血清を用いてMp抗体価（PA法）を測定した。Mpの診断は，LAMP法が陽性またはPA法による抗体価が4倍以上の上昇とした。Mpの非流行期（2014年1月～2015年7月）および流行期（2015年8月～2016年3月）に群分けし，LAMP法とペア血清に対するリボテストの有用性を比較検討した。対象は1,140例であり，うちMp肺炎と診断した対象は237例（21％）であった。Mp肺炎に対するリボテストの感度は非流行期および流行期で各々23％（16／70），22％（36／167）といずれも低値であった。血清診断例（n＝203）に対するリボテストの感度は，非流行期および流行期で各々25％（13／51），22％（34／152）であり，LAMP法と比べて有意に低値であった。リボテスト偽陽性は非流行期に16例（2％），流行期に6例（1％）であり，またリボテストの陽性的中率は，流行期の86％（36／42）より非流行期の50％（16／32）の方が有意に低値であった。多変量解析では，リボテスト偽陽性者は入院病日（発熱）が短く，他病原体の検出割合が高値であった（p＜0.01）。Mpの診断には，感度や陽性的中率の低いリボテストはLAMP法などの検査より有用性が劣るため，総合的に判断することが重要である。

Rapid and broad detection of H5 hemagglutinin by an immunochromatographic kit using novel monoclonal antibody against highly pathogenic avian influenza virus belonging to the genetic clade 2.3.4.4.

Highly pathogenic avian influenza viruses (HPAIVs) of H5 subtype have persistently caused outbreaks in domestic poultry and wild birds worldwide and sporadically infected humans. Rapid and accurate diagnosis is one of the key strategies for the control of H5 HPAIVs. However, the sensitivity of the diagnosis of H5 HPAIVs has gradually reduced due to extensive antigenic variation during their evolution. Particularly, the previously developed immunochromatographic diagnosis kit for H5 viruses, Linjudge Flu A/H5, exhibits reduced detection of H5 HPAIVs isolated in recent years. In the present study, we established a new advanced H5 rapid immunochromatographic detection kit (New Linjudge Flu A/H5) by a combination of two anti-H5 hemagglutinin monoclonal antibodies, A64/1 previously applied in the Linjudge Flu A/H5 and A32/2, a novel monoclonal antibody generated from a clade 2.3.4.4 H5 HPAIV. The new kit broadly detected all classical and recent H5 influenza viruses and showed a higher specificity and sensitivity than the original Linjudge Flu A/H5 with recently circulating H5 HPAIVs. Furthermore, the applicability of the New Linjudge Flu A/H5 was demonstrated by detecting antigens from the swabs and tissue homogenates of naturally infected birds and experimentally infected chickens with H5N6 HPAIVs belonging to the genetic clade 2.3.4.4. Our study, therefore, can provide an effective point-of-care rapid antigen detection kit for the surveillance of H5 avian influenza viruses and as a prompt countermeasure against the current widespread of the clade 2.3.4.4 H5 HPAIVs in domestic and wild birds.

Clinical value of a rapid respiratory syncytial virus antigen detection in point-of-care testing

Objective: To evaluate the clinical value of a rapid respiratory syncytial virus (RSV) antigen detection in point-of-care testing (POCT). Method: A total of 209 specimens, including 78 throat swabs (TS) and 131 nasopharyngeal aspirates (NPAs), were collected from inpatients who visited the Children's Hospital Affiliated to the Capital Institute of Pediatrics and were diagnosed as acute respiratory infection from 5 January to 7 February, 2015. These specimens were tested for RSV by a rapid antigen detection kit which was compared with reverse transcription polymerase chain reaction (RT-PCR) and direct immunofluorescence assay (DFA) for RSV detection. Result: Compared with DFA for NPAs, the sensitivity and specificity of rapid antigen detection were 83.9% and 97.3%, respectively, with Kappa value of 0.86; Compared with RT-PCR, the sensitivity (NPAs, 74.2%; TS, 77.8%) and specificity (NPAs, 100.0%; TS, 92.0%) of rapid antigen detection were high, too, with Kappa value of 0.74 in NPAs and 0.62 in TS. However, the RSV positive rate of rapid antigen detection in TS (21.7%) from pediatric patients with acute lower respiratory tract infection was lower than that in NPAs (78.3%), as well as that of RT-PCR (7.3% in TS verse 78% in NPAs). The RSV rapid antigen detection kit can be finished in about 10 minutes. Conclusion: With characteristics of high specificity, high sensitivity, being rapid, efficient and easy to operate in comparison with DFA and RT-PCR, RSV rapid antigen detection in this study is suitable for POCT. For pediatric patients with acute respiratory tract infection, NPA was better than TS for RSV detection.

Evaluation of the rapid immunochromatographic ODK0501 assay for Streptococcus pneumoniae antigen detection with nasopharyngeal swabs: preliminary report.

BackgroundEarly identification and control of pathogenic bacteria are important in the treatment of pneumonia. Currently, two rapid antigen detection kits for pneumococcal pneumonia are available: one uses urine samples and the other, named RAPIRUN® S. pneumoniae, uses sputum samples. RAPIRUN® has shown high sensitivity with nasopharyngeal swab samples from pediatric patients. In this study, we investigated the performance of RAPIRUN® with nasopharyngeal swabs from adult patients.MethodsAll adult patients diagnosed with pneumonia from November 2011 to April 2012 in St. Luke’s International hospital were included in this cross-sectional study. Single sputum, nasopharyngeal swab, and urine samples obtained from patients were investigated using a rapid antigen detection kit. Sputum and blood cultures were also evaluated. We compared the characteristics of pneumococcal pneumonia patients diagnosed using RAPIRUN with a nasopharyngeal swab to those patients diagnosed using other methods. Sensitivity and specificity were also calculated.ResultsSeventeen out of 60 patients with pneumonia were diagnosed with pneumococcal pneumonia. In 4 out of the 17 cases, a positive test result was obtained using RAPIRUN with a nasopharyngeal swab. The sensitivity and specificity were 23.5 and 100 %, respectively.ConclusionRAPIRUN performed with nasopharyngeal swabs from adult patients exhibited lower sensitivity for the diagnosis of pneumococcal pneumonia than the other compared methods. The causative pathogen of pneumonia should be identified using not only sputum cultures or rapid antigen detection kits but also clinical features or gram staining of sputum.

Evaluation of the rapid immunochromatographic ODK0501 assay for Streptococcus pneumoniae antigen detection with nasopharyngeal swabs: preliminary report

Background: Early identification and control of pathogenic bacteria are important in the treatment of pneumonia. Currently, two rapid antigen detection kits for pneumococcal pneumonia are available: one uses urine samples and the other, named RAPIRUN® S. pneumoniae, uses sputum samples. RAPIRUN® has shown high sensitivity with nasopharyngeal swab samples from pediatric patients. In this study, we investigated the performance of RAPIRUN® with nasopharyngeal swabs from adult patients. Methods: All adult patients diagnosed with pneumonia from November 2011 to April 2012 in St. Luke’s International hospital were included in this cross-sectional study. Single sputum, nasopharyngeal swab, and urine samples obtained from patients were investigated using a rapid antigen detection kit. Sputum and blood cultures were also evaluated. We compared the characteristics of pneumococcal pneumonia patients diagnosed using RAPIRUN with a nasopharyngeal swab to those patients diagnosed using other methods. Sensitivity and specificity were also calculated. Results: Seventeen out of 60 patients with pneumonia were diagnosed with pneumococcal pneumonia. In 4 out of the 17 cases, a positive test result was obtained using RAPIRUN with a nasopharyngeal swab. The sensitivity and specificity were 23.5 and 100 %, respectively. Conclusion: RAPIRUN performed with nasopharyngeal swabs from adult patients exhibited lower sensitivity for the diagnosis of pneumococcal pneumonia than the other compared methods. The causative pathogen of pneumonia should be identified using not only sputum cultures or rapid antigen detection kits but also clinical features or gram staining of sputum.

Prevalence of canine Parvo virus infection in street dogs using rapid antigen detection Kit

Canine parvovirus is one of the most common infectious diseases of dogs. A study was carried out to diagnose the infection of canine parvovirus in street dogs from different places of Mymensingh Town. Rectal samples were collected from January to April, 2015. A total of 114 rectal swabs were collected conveniently from street dogs of Mymensingh. The samples were diagnosed using RapiGEN Canine Parvo Virus Ag Test Kit. The association of CPV infection with demographic variables was assessed by Chisquare test. The overall prevalence of CPV was 32.0% in dogs. The prevalence of parvovirus infection was found to be significantly higher in puppies and 6 months of age (58.3%) than those >24 months of age (p=0.005). The prevalence of canine parvovirus infection also varied significantly in different study area (p=0.003). The prevalence of canine parvovirus infection was higher in male (34.4%) than that in female (30.2%) but it was not statistically significant.Res. Agric., Livest. Fish.2(3): 459-464, December 2015

Sequence Diversity of VP4 and VP7 Genes of Human Rotavirus Strains in Saudi Arabia.

Group A rotavirus is responsible for inducing severe diarrhea in young children worldwide. Rotavirus vaccines are used to control the disease in many countries. In the current study, the sequences of human rotavirus G and P types in Saudi Arabia are reported and compared to different relevant published sequences. In addition, the VP4 and VP7 genes of the G1P[8] strains are compared to different antigenic epitopes of the rotavirus vaccines. Stool samples were collected from children under 2 years suffering from severe diarrhea. Screening of the rotavirus-positive samples was performed with rapid antigen detection kit. RNA was amplified from rotavirus-positive samples by reverse transcriptase polymerase chain reaction assay for both VP4 and VP7 genes. Direct sequencing of the VP4 and VP7 genes was conducted and the obtained sequences were compared to each other and to the rotavirus vaccines. Both G1P[8] G1P[4] genotypes were detected. Phylogenetic analysis revealed that the detected strains belong to G1 lineage 1 and 2, P[8] lineage 3, and to P[4] lineage 5. Multiple amino acid substitutions were detected between the Saudi RVA strains and the commonly used vaccines. The current findings emphasize the importance of the continuous surveillance of the circulating rotavirus strains, which is crucial for monitoring virus evolution and helping in predicting the protection level afforded by rotavirus vaccines.

English

BACKGROUND: Malaria is the most important protozoan disease in India. The mortality and morbidity associated with this disease is considerably high whereas only limited diagnostic modalities are available in India. AIMS: To compare the conventional peripheral smear examination with Quantitative buffy coat (QBC) and rapid antigen detection kits. MATERIALS & METHODS: In the present study a total of 200 patients with clinically suspected malaria are screened with various techniques including conventional peripheral smear examinations with Giemsa, Leishman and JSB stain and newer modalities like Quantitative buffy coat testing and rapid antigen detection kits detecting PLDH. RESULTS: Among all these methodologies QBC test has shown highest sensitivity and antigen detection kit showed least sensitivity in the diagnosis of malaria.

A phylogenetically distinct Middle East respiratory syndrome coronavirus detected in a dromedary calf from a closed dairy herd in Dubai with rising seroprevalence with age

Middle East respiratory syndrome coronavirus (MERS-CoV) was detected by monoclonal antibody-based nucleocapsid protein-capture enzyme-linked immunosorbent assay (ELISA), RNA detection, and viral culture from the nasal sample of a 1-month-old dromedary calf in Dubai with sudden death. Whole genome phylogeny showed that this MERS-CoV strain did not cluster with the other MERS-CoV strains from Dubai that we reported recently. Instead, it formed a unique branch more closely related to other MERS-CoV strains from patients in Qatar and Hafr-Al-Batin in Saudi Arabia, as well as the MERS-CoV strains from patients in the recent Korean outbreak, in which the index patient acquired the infection during travel in the eastern part of the Arabian Peninsula. Non-synonymous mutations, resulting in 11 unique amino acid differences, were observed between the MERS-CoV genome from the present study and all the other available MERS-CoV genomes. Among these 11 unique amino acid differences, four were found in ORF1ab, three were found in the S1 domain of the spike protein, and one each was found in the proteins encoded by ORF4b, ORF5, envelope gene, and ORF8. MERS-CoV detection for all other 254 dromedaries in this closed dairy herd was negative by nucleocapsid protein-capture ELISA and RNA detection. MERS-CoV IgG sero-positivity gradually increased in dromedary calves with increasing age, with positivity rates of 75% at zero to three months, 79% at four months, 89% at five to six months, and 90% at seven to twelve months. The development of a rapid antigen detection kit for instantaneous diagnosis is warranted.

Dengue NS1 antigen as a marker of severe clinical disease

BackgroundEarly detection of complications significantly reduces dengue associated mortality and morbidity. We set out to determine if the NS1 rapid antigen detection test could be used as a point of care test to predict severe disease.Methods186 adult patients with confirmed dengue were enrolled during day 3-8 of illness. Clinical and laboratory parameters were recorded during the course of the illness and NS1 antigen levels were determined using both the Panbio dengue early ELISA (Panbio, Australia) and a NS1 rapid antigen detection kit (SD Bioline, South Korea).Results59.1% of patients presented to hospital on day 5-6 of illness when NS1 antigen positivity was significantly (p = 0.008) associated with severe dengue (odds ratio 3.0, 95% CI 1.39 to 6.47) and the NS1 antigen levels were significantly higher (p = 0.03) in those who went on to develop shock. Serum NS1 antigen levels significantly (p < 0.0001) and inversely correlated with the total white cell counts and lymphocyte counts. The bedside NS1 test showed comparable sensitivity (97.4%) and specificity (93.7%) to the laboratory NS1 test in our setting and cohort.ConclusionNS1 antigen positivity is associated with a higher risk of developing severe dengue especially when positive beyond day 5 of illness in our cohort, and while further validation studies are required, the test can therefore potentially be used as a bedside point of care test as a warning sign of severe dengue.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-014-0570-8) contains supplementary material, which is available to authorized users.

Occurrence of Pasteurellosis and Newcastle Disease in indigenous chickens in Sirajgonj district

A study was carried out on indigenous layer chickens to know occurrence of Avian Pasteurellosis (AP) and Newcastle disease (ND) in Sirajgonj during the period from January/2012 to December/2013. The clinical signs showed before death was recorded by taking history and the birds were subjected to post mortem examination. In addition to the clinical and necropsy findings, ND was detected by Anigen® rapid antigen detection kit. The AP was confirmed by isolation and identification of Pasteurella (P.) multocida from liver, spleen and heart samples. The P. multocida was found to grow on nutrient broth, nutrient agar, blood agar and Eosin Methylene Blue agar where it produced whitish, opaque, round, flat, translucent colonies. It produced turbidity on nutrient broth. The organism was not found to grow on MacConkey agar media and did not cause hemolysis on blood agar media. The impression smear of liver and heart blood were stained by Gram’s staining, Leishman staining and Methylene blue staining techniques to detect P. multocida. P. multocida organism was also found to fermnt dextrose, lactose and mannitol with the production of only acid but did not ferment maltose and lactose. P. mutocida was found non-motile, indole positive and urease negative. On triple sugar iron test it produced H2S and fermented only glucose. It was found negative to both methyl red test and Voges Proskauer test. Out of 360 birds tested 59.72% (215) was AP positive and 40.28% was ND positive. Age, Sex, season and mortality due to other diseases were not considered.DOI: http://dx.doi.org/10.3329/bjvm.v11i2.19123 Bangl. J. Vet. Med. (2013). 11 (2): 97-105

The evaluation of three diagnostic tests for the detection of equine influenza nucleoprotein in nasal swabs

BackgroundEquine influenza (EI) is a highly contagious respiratory disease of horses.ObjectivesThe aim of this study was to evaluate two rapid antigen detection kits (Directigen or DFA, and Espline) and a commercial ELISA for the detection of EI nucleoprotein in nasal swabs.MethodNasal swab samples from naturally and experimentally infected horses were used to compare the sensitivity and specificity of these assays to virus isolation (VI) and real-time RT-PCR.ResultsIf real-time RT-PCR was considered as the gold standard, the sensitivity of the other tests in field samples was 68% (DFA), 35% (ELISA), 29% (Espline), and 9% (VI). These tests had 100% specificity when compared to real-time RT-PCR. A receiver operating characteristic (ROC) curve indicated that decreasing the cutoff of the ELISA would increase sensitivity with some loss of specificity. In samples from experimentally infected horses, the sensitivity of the tests compared with real-time RT-PCR was 69% (VI), 27% (DFA), 6% (Espline), and 2% (ELISA). The specificity was 100% for Espline and ELISA and 95% for VI and DFA.ConclusionsThis study illustrated that DFA is the most sensitive antigen detection test evaluated for the diagnosis of EI and that it can detect virus in some subclinical infected and vaccinated horses. The results suggest that DFA is a useful adjunct to laboratory tests and may be effective as a screening test in a quarantine station or similar facility where horses are monitored daily.