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Infectious laryngotracheitis disease is an acute, highly contagious viral disease seriously affecting poultry industry worldwide. In this study, a rapid and simple immune colloidal gold test strip for detecting infectious laryngotracheitis virus (ILTV) was developed based on membrane chromatography with monoclonal antibodies (mAbs) against gJ protein of ILTV and systematically evaluated for the detection of ILTV from clinical samples. mAb 2D4 1D7 was conjugated with colloidal gold as the detector antibody on the test strip. Another mAb, 1D8 1G3, was used as the capture complex at the test line (T-line), and goat antimouse IgG antibody was used as the capture antibody at the control line (C-line). The colloidal gold test strip showed high specificity in the detection of ILTV, with no cross-reaction with other avian pathogens, including infectious bronchitis virus, infectious bursal disease virus, avian influenza virus, Newcastle disease virus, fowl adenoviruses, and Marek's disease virus. Besides, the detection limit of this method was as low as 60 ELD50/mL for the ILTV Wanggang strain. Furthermore, we evaluated its application in 260 clinical samples suspected of infection with ILTV. Results from the strip test were nearly identical with those from real-time PCR (coincidence rate 99.6%) and showed higher sensitivity than conventional PCR. All the results obtained in this study indicated that the colloidal gold test strip can be applied as a simple, rapid, sensitive, and specific diagnostic tool for the detection of ILTV, especially in resource-limited areas.

The aim of this study was to develop a multiple PCR assay based on the suspension array system for the simultaneous detection of respiratory and reproductive pathogens in swine. Pseudorabies virus (PRV), Japanese encephalitis virus (JEV), classic swine fever virus (CFSV), African swine fever virus (ASFV), porcine circovirus type 2 (PCV-2), porcine reproductive and respiratory syndrome virus (PRRSV) and porcine parvovirus (PPV) are the major respiratory and reproductive viral pathogens in pig farms. Seven pairs of specific primers and probes were designed, and the multiple PCR was performed, with the PCR products hybridized to beads coupled to probes, which were then detected by Bio-Plex suspension array system. The limit of detection, specificity and repeatability of this method was determined. The assay was further tested using 137 clinical samples, and the results were compared with conventional PCR to evaluate the ability of the method to diagnose porcine viruses. The results showed that the assay had a high degree of specificity and repeatability, and the simultaneous detection limit for the seven viruses reached 103 copies/μL. Forty-nine of the clinical samples tested positive for at least one of the viruses, the principal viral infections in the clinical samples were PCV-2 and PRRSV. The suspension method represented a rapid, specific and high-throughput tool for single or mixed detection of the seven porcine viruses simultaneously, and has great significance for the development of liquid chip techniques for the diagnosis of diseases in animals.

This study was aimed to establish a highly specific and sensitive loop-mediated isothermal amplification (LAMP) method for diagnosing avian infectious laryngotracheitis (AILT). DNA was extracted from isolated infectious laryngotracheitis virus (ILTV) strains and control samples, followed by PCR using three sets of six specific primers. The detection efficiency of the LAMP assay was evaluated by the turbidity and calcein methods. The sensitivity of LAMP was then assessed using a concentration gradient followed by a specificity analysis. Furthermore, the detection efficiency of LAMP and PCR was compared. Finally, a clinical test was performed to evaluate the value of the LAMP assay. The optimal temperature for the LAMP reaction was 66 °C. Meanwhile, the primers selected for the LAMP assay were highly specific for the target virus. The sensitivity of the turbidity and calcein methods for LAMP was consistent. The minimum detection concentration of LAMP was 0.06 pg/μL, which was 100-fold higher than that of PCR. Furthermore, the results from clinical samples showed that the LAMP method could identify AILT from many samples. The newly designed LAMP assay was an effective method for AILT detection at an optimal temperature of 66 °C with a minimum detection concentration of 0.06 pg/µL.

Giardia duodenalis is an important parasite with veterinary and public health significance worldwide. The presence and zoonotic assemblages of G. duodenalis have previously been reported in rabbits. In this study, to understand the infection status of G. duodenalis in rabbits from Shaanxi province, a total of 537 fecal samples were collected from two breeds of rabbits in four age groups (30 days, 31-90 days, 91-200 days and200 days) from four geographical origins (Fengxiang, Yangling, Tongchuan, and Shanyang). The presence of G. duodenalis in these samples was assessed using molecular assays based on beta-giardin (bg). The glutamate dehydrogenase (gdh) and triosephosphate isomerase (tpi) loci were then amplified in the bg-positive samples for multi-locus genotype (MLG) analysis. The total prevalence of G. duodenalis in these rabbits was 3.54% (19/537). Giardia duodenalis infection was found in both breeds of rabbits, and in all farms and age groups, but with no statistically significant differences related to these factors (p 0.05). Two assemblages, including B and E, were identified, with the former the predominant assemblage detected in both breeds, and in all age groups and farms. Sequence analysis revealed 2 (named as rbg1-2), 1 (named as rtpi1), and 2 (named as rgdh1-2) haplotypes at the gene loci of bg, tpi, and gdh, respectively, forming a multilocus genotype (MLG) of assemblage B (rbg1, rtpi1, and rgdh1). These findings reveal the significant zoonotic potential and genetic diversity of G. duodenalis in rabbits in Shaanxi Province, PR China.Prévalence et génotypage multi-locus de Giardia duodenalis chez les lapins de la province du Shaanxi, nord-ouest de la Chine.Giardia duodenalis est un parasite de grande importance vétérinaire et en santé publique dans le monde entier. La présence et les assemblages zoonotiques de G. duodenalis ont déjà été rapportés chez le lapin. Dans cette étude, pour comprendre le statut infectieux de G. duodenalis chez les lapins de la province du Shaanxi, un total de 537 échantillons fécaux ont été prélevés sur deux races de lapins dans quatre groupes d’âge (30 jours, 31–90 jours, 91–200 jours et200 jours) de quatre origines géographiques (Fengxiang, Yangling, Tongchuan, Shanyang). La présence de G. duodenalis dans ces échantillons a été évaluée à l’aide de tests moléculaires basés sur la bêta-giardine (bg). Les loci de la glutamate déshydrogénase (gdh) et de la triosephosphate isomérase (tpi) ont ensuite été amplifiés dans les échantillons bg-positifs pour l’analyse des génotypes multilocus (MLG). La prévalence totale de G. duodenalis chez ces lapins était de 3,54 % (19/537). L’infection à Giardia duodenalis a été trouvée chez les deux races de lapins et dans tous les élevages et groupes d’âge, mais sans différence statistiquement significative liée à ces facteurs (p 0,05). Deux assemblages, dont B et E, ont été identifiés, le premier étant l’assemblage prédominant détecté dans les deux races, et dans tous les groupes d’âge et élevages. L’analyse des séquences a révélé des haplotypes, 2 (nommés rbg1-2), 1 (nommé rtpi1) et 2 (nommés rgdh1-2) aux loci des gènes de bg, tpi et gdh, respectivement, formant un génotype multilocus (MLG) de l’assemblage B (rbg1, rtpi1 et rgdh1). Ces résultats ont révélé l’important potentiel zoonotique et la diversité génétique de G. duodenalis chez les lapins de la province chinoise du Shaanxi.