Performance of four different diagnostic tests for C. difficile infection in piglets

Clostridium difficile is emerging as a pathogen in man as well as in animals. In 2000 it was described as a cause of neonatal enteritis in piglets and it is now the most common cause of neonatal diarrhoea in the USA. In Europe, C. difficile infection (CDI) in neonatal piglets has also been reported. Diagnosis of this infection is based on detection of the bacterium or its toxins A and B

Preparation of Newcastle disease virus fluorescent conjugate by immunization of chicken

The fluorescent conjugate for diagnosis of Newcastle disease was prepared in 6-week-old chickens by immunization with Newcastle disease virus (NDV), strain F and local isolated strain NK1180/42. The antisera with high neutralizing antibodies titers were collected and pooled.The immunoglobulin was fractionated and conjugated with the fluorescein isothiocyanate (FITC). The conjugate was tested for the specificity in NDV infected chorioallantoic membrane (CAM) and cryostat sections of tracheal epithelium, lung, heart, kidney, spleen, liver, Bursa of Fabricius, brain and intestine. A distinctive fluorescence was seen in the cytoplasm of infected cells of trachea, spleen, Bursa of Fabricius and intestine 48-72 hours after innoculation. The prepared conjugate was specific to NDV and diagnosis and result could be made in 1-2 hours

Seroepidemiological survey on Japanese encephalitis virus in swine raising on the southern border of Thailand

From February to March 1999, a seroepidemiological survey on Japanese encephalitis virus (JEV) was carried out. One thousand and thirteen serum samples of swine were collected from 37 farms in 4 provinces at the southern border of Thailand; Songkhla, Yala, Narathiwat and Satun. Japanese encephalitis virus antibody was measured using microtiter hemagglutination inhibition (HI) test. The results indicated that 95.12 - 99.42% of the breeder pigs had JE-HI antibodies at > 1:40 compared with 89.08% of the gilts. The percentages of seropositive animals were 49.75%, 50.65% and 100% in fattening pigs, weaning and suckling piglets, respectively. The study demonstrated a high exposure rate of JEV infection among swine population raised on the southern border of Thailand

The indirect immunofluorescence assay using cardiac tissue from chickens, quails and ducks for identification of influenza A virus during an outbreak of highly pathogenic avian influenza virus (H5N1): a rapid and simple screening tool for limited resource settings.

Here we describe the diagnostic utility of the indirect immunofluorescence assay (IFA) during a recent outbreak of highly pathogenic avian influenza (HPAI) subtype H5N1 virus in southern Thailand and demonstrate the usefulness of the cardiac tissue from infected chickens, quail, and ducks for diagnosis. The most reliable sample for IFA diagnosis of influenza A virus was cardiac tissue (83.0%; 44/53) which when divided by species (chicken, quail and duck cardiac tissues) gave respective positivity rates of 88% (22/25), 88.9% (16/18) and 60.0% (6/10). Cardiac tissue also gave the highest IFA intensity for the three species. We believe that the IFA method has wide applicability in developing countries or remote settings where clinically similar avian diseases with high morbidity and mortality such as Newcastle disease and fowl cholera are common and could be rapidly excluded thereby conserving valuable reference laboratory capacity for true HPAI outbreaks

Tissue tropism of a Thailand strain of high-pathogenicity avian influenza virus (H5N1) in tissues of naturally infected native chickens (Gallus gallus), Japanese quail (Coturnix coturnix japonica) and ducks (Anas spp.).

The tropism of a Thailand strain of highly pathogenic avian influenza H5N1 virus was demonstrated on tissues (lung, trachea, heart, liver, spleen, pancreas, rectum, kidney, brain, skeletal muscle, duodenum, and oviduct) from naturally infected native chickens (Gallus gallus), Japanese quail (Coturnix coturnix japonica) and ducks (Anas spp.) by indirect immunofluorescence assay. In chickens and quail, the distribution and localization of nucleoprotein viral antigen was similar and detected at the highest level in cardiac myocytes, at 88% (chickens) and 89% (quail), and respiratory, digestive and urinary systems all showed high levels of antigen. Antigen in duck tissues were detected at significantly lower levels (P < 0.05) with the exception of brain and skeletal muscle samples. In most cases, antigen in duck tissue was absent in the digestive organs but present in respiratory organs, which supports the hypothesis that aerosol and oral-oral transmission are the main method of highly pathogenic avian influenza virus transmission from this species

Mapping of the receptor-binding domain and amino acids critical for attachment in the spike protein of avian coronavirus infectious bronchitis virus

The infection of the avian coronavirus infectious bronchitis virus (IBV) is initiated by the binding of the spike glycoprotein S to sialic acids on the chicken host cell. In this study we identified the receptor-binding domain (RBD) of the spike of the prototype IBV strain M41. By analyzing the ability of recombinantly expressed chimeric and truncated spike proteins to bind to chicken tissues, we demonstrate that the N-terminal 253 amino acids of the spike are both required and sufficient for binding to chicken respiratory tract in an α-2,3-sialic acid-dependent manner. Critical amino acids for attachment of M41 spike are present within the N-terminal residues 19-69, which overlap with a hypervariable region in the S1 gene. Our results may help to understand the differences between IBV S1 genotypes and the ultimate pathogenesis of IBV in chickens

Performance of four different diagnostic tests for C. difficile infection in piglets

Clostridium difficile is emerging as a pathogen in man as well as in animals. In 2000 it was described as a cause of neonatal enteritis in piglets and it is now the most common cause of neonatal diarrhoea in the USA. In Europe, C. difficile infection (CDI) in neonatal piglets has also been reported. Diagnosis of this infection is based on detection of the bacterium or its toxins A and B.</p