Respiratory Clinical Signs Research Articles

First Report of Influenza D Virus in Dairy Cattle in Pakistan

Influenza D virus (IDV) is a newly emerged zoonotic virus increasingly reported worldwide. Cattle are considered the main reservoir of IDV, although it was first isolated from pigs. IDV infects multiple animal species and contributes to the bovine respiratory disease complex (BRDC). To date, there has been no report on the presence and frequency of IDV among cattle herds in Pakistan. In this study, we collected nasal swabs from cattle and performed virological surveillance of IDV via qRT-PCR. Among 376 swab samples, IDV was detected in 9 samples (2.4%). Four dairy cattle farms were positive for IDV; two IDV-positive samples (two/nine, 22.2%) belonged to asymptomatic cattle, while seven IDV-positive samples (seven/nine, 77.8%) were from cattle showing respiratory clinical signs, including two with a recent history of abortion and mastitis. Partial sequences of the hemagglutinin–esterase-fusion gene of IDV were obtained from nine qRT-PCR-positive samples. Notably, all IDV strains in this study clustered within the D/OK lineages in phylogenetic analysis. A 98.8–99.6% genetic identity to its European and US counterparts indicates that the IDVs are closely related. The D/OK lineage of IDV was previously unreported in Pakistan. This is the first report of IDV in Pakistan. We confirmed that IDV is circulating among cattle herds in Pakistan. This study underscores the importance of virological surveillance to monitor the ecology of IDV for better animal and public health. The continued spread of IDV and its adaptation to various hosts necessitate further epidemiological studies.

First detection of D181 genotype of infectious bronchitis in poultry flocks of Morocco

BackgroundThis paper reports the first pathological and molecular characterization of the novel variant of infectious bronchitis virus (IBV) D181 in poultry flocks in Morocco and Africa.MethodsThe study includes six poultry farms, involving three flocks of layers aged between 28 and 67 weeks and three broiler flocks aged 27, 39 and 42 days from different regions of Morocco. In all affected layer flocks, a severe drop in egg production with poor eggshell quality was reported. Necropsy of dead birds was carried out, and samples of trachea, lungs, oviduct, ovaries, and kidneys were fixed in 10% neutral buffered formalin for histopathologic examinations, while other portions were stored at -20 °C for molecular analysis. Real time RT-qPCR for IBV gene group was performed, and IBV variants were identified. Partial S1 gene sequences were amplified by conventional RT-PCR, sequenced, and aligned for phylogenetic and amino acid similarity analysis.ResultsNecropsy of dead birds revealed misshapen and hemorrhagic ovarian follicles with an edematous oviduct and severe reaction in the cecal tonsils. A caseous material accumulation in the sinus was noted in few birds. In contrast, the broiler flocks exhibited respiratory clinical signs such as difficulty in breathing, sneezing, tracheal rales, watery eyes and lethargy, associated with a decrease in feed consumption. Mortality in broiler ranged from 2 to 15%. Histopathological analysis of samples showed a lympho-plasmocytic inflammation in the oviduct, trachea, and lungs. Individual necrosis of epithelial cells, with sloughing of the bronchial epithelium and accumulation of desquamated cells with mucus in the airways, was observed in some birds. Partial S1 gene sequencing and phylogenetic analyses showed that the Moroccan strains were very closely related to D181 strains isolated in Dutch layers and breeders in 2018. Nucleotide sequence identities reached 90.9–95% with the Dutch isolates (strain CK/NL/D181/2018).ConclusionOur sequencing results demonstrate for the first time that the D181 IBV genotype is circulating in Moroccan poultry. These findings justify permanent monitoring of circulating strains in order to appropriately adjust vaccination strategies to align with the evolving field situation.

Exposure to respirable silica contributes to lower airway inflammation in asthmatic horses.

Respirable mineral particles can induce lower airway inflammation, but the role they play in asthma of horses is unknown. Respirable mineral particles, particularly respirable silica, are an overlooked determinant of chronic lung inflammation (asthma) in horses. Twenty-three horses from an equine hospital population: 11 moderately affected (MEA), 7 severely asthmatic (SEA), and 5 control horses free from respiratory clinical signs. Prospective observational study. The quantity and quality of mineral particles found in bronchoalveolar lavage fluid (BALF) were characterized, with particular attention to silica content. Polarized light microscopy performed on cytospin slides identified intracellular birefringent particles as silica. Spectrometry-based analysis performed on whole BALF determined total mineral and silica percentage and concentration. Group-related differences in BALF mineral and silica load were investigated as well as associations with BALF cytology. Intracellular birefringent particles were increased in SEA vs MEA (median [interquartile range, IQR]), 12 [7] vs 4 [5] particles/30 high power fields [hpf], respectively; P = .01) and vs controls (4 [2] particles/30 hpf; P = .02). Total mineral concentration in BALF was similar between the groups studied, whereas silica concentration and percentage were increased in SEA vs MEA (1758 [887] particles/mL and 20 [10]% vs 867 [662] particles/mL and 8 [6]%; P = .009 and P = .001) and control group (355 [330] particles/mL and 6 [3]%; P = .0003 and P = .002). Silica load in BALF was associated with BALF neutrophilia in MEA and SEA. Respirable silica is associated with neutrophilic lower airway inflammation in horses and might contribute to asthma development.

Choosing the optimal combination of lungs lobe evaluation during focused pulmonary ultrasonography in calves

Bovine respiratory disease (BRD) poses significant challenges on beef and dairy farms, impacting mortality rates, animal welfare, and production efficiency. Although pulmonary ultrasonography is highly sensitive and specific for monitoring lung lesions and diagnosing BRD, its practical application could be optimized by focusing on the most commonly affected lung lobes. This study first evaluated the efficacy of focused lung ultrasonography for diagnosing BRD in calves, examining individual lung lobes and their associations versus the extensive lung scanning under various disease prevalence scenarios. Then, the relationship between individual and combined clinical respiratory signs vs lung consolidation was analyzed. In a combined analysis, 193 Holstein calves from a longitudinal study and 112 Angus calves from a cross-sectional study underwent a total of 1265 complete bilateral thoracic ultrasonographic evaluations from 1 to 6 mo of age. Then, it was assessed the agreement and sensitivity of specific lung lobe combinations compared with the findings from total lung ultrasonography. The Classification and Regression Tree (CART) algorithm was used to suggest an optimal examination sequence, and logistic regression was applied to associate specific clinical signs with the presence of lung consolidation adjusting for breed and calf age. Findings reveal that the most sensitive areas are cranial (K: 0.867; Se: 84.7%) and the caudal (K: 0.433; Se: 40.3%) portions of the right cranial lobe, the caudal portion (K: 0.235; Se: 20.6%) of the left cranial lobe, and the middle lobe (K: 0.25; Se: 22%). The optimal lobe combinations for focused lung ultrasonography were identified as the right cranial lobe paired with either the left cranial lobe or the middle lobe. Focused techniques achieved sensitivity over 94% and maintained good agreement. Using these focused techniques were relatively robust to various true lung consolidation scenarios. CART analysis recommended initiating examinations with the right cranial lobe, proceeding to the left cranial lobe, and concluding with the middle lobe. While spontaneous cough was linked to pneumonia presence, reliance on a single clinical sign is not advised due to low sensitivity (26.8%) and high specificity (85.4%); it should merely prompt further ultrasound assessment. In conclusion, focused lung ultrasonography, especially utilizing the right cranial lobe in conjunction with the left cranial lobe or the middle lobe, emerged as effective strategies for focused pulmonary ultrasonography, preserving the accuracy of the results.

Cardiac biomarker profiles in dogs with naturally occurring precapillary pulmonary hypertension

Introduction/ObjectivesThis study evaluated circulating amino-terminal pro-B-type natriuretic peptide (NT-proBNP), amino-terminal pro-A-type natriuretic peptide (NT-proANP), and cardiac troponin I (cTnI) concentrations in dogs with precapillary pulmonary hypertension (Pre-PH) and control dogs with respiratory clinical signs but no Pre-PH. AnimalsTwenty-six dogs (17 affected, and 9 controls) were involved in the study. Materials and MethodsThis was a sub-study of a large prospective single-center observational study. Dogs underwent blood sample collection, physical examination, and echocardiographic evaluation. Pre-PH was diagnosed when a calculated right ventricular-to-right atrial pressure gradient (RV:RA PG) measuring ≥40 mmHg was identified echocardiographically, barring right ventricular outflow obstruction and/or left-sided cardiac disease. ResultsTwo, nine, and six dogs had mild, moderate, and severe Pre-PH, respectively. Plasma concentrations of NT-proBNP, NT-proANP, and cTnI were significantly higher in the affected group than in the control group (P=0.020, P=0.009, P=0.011, respectively). There was a positive correlation between RV:RA PG and NT-proBNP (r = 0.52), NT-proANP (r = 0.54), and cTnI (r = 0.67) concentrations. DiscussionPre-PH should be included in the differential diagnosis list of elevated cardiac biomarker concentrations in dogs with respiratory signs. Study LimitationsStrict selection criteria reduced group sizes. There were rare missing data points. The diagnosis of Pre-PH was obtained from Doppler echocardiographic RV:RA PG. The disease process causing Pre-PH was not evaluated histopathologically. ConclusionsCirculating cardiac biomarker concentrations are increased in dogs with Pre-PH and there is a positive correlation between RV:RA PG and NT-proBNP, NT-proANP, and cTnI concentrations.

Post Obstructive Acute Pulmonary Edema after Sedation

Post-obstructive acute pulmonary edema (POAPE) is a serious and rare respiratory complication, especially under sedation. We report the case of a patient without comorbidities undergoing sedated colonoscopy who developed respiratory distress, desaturation, and clinical and radiological signs suggestive of acute pulmonary edema. Etiological investigations, including cardiac assessment, returned normal, and the patient's condition improved within hours. The diagnosis of post-obstructive pulmonary edema was established. Through this case report, we emphasize the seriousness of this complication, necessitating early intervention.

Evaluation of remote assistance for point-of-care ultrasonography in a large animal hospital: a controlled randomized trial.

To assess whether remote assistance is beneficial to the accuracy of point-of-care ultrasound (POCUS) examinations during equine emergency evaluations. Adult horses presenting to a tertiary care large animal emergency service for respiratory or gastrointestinal clinical signs. Prospective, randomized, controlled, clinical study. Cases were assigned to receive POCUS with remote assistance ("POCUS-R" group) or POCUS with no assistance ("POCUS" group). Accuracy of diagnosis, duration of sonograms and survival to discharge were the objective outcomes compared between groups. Perceptions about the use of teleultrasound were gathered using a survey. 29 cases were enrolled in the study over an 18-month period. Based on Cox regression estimates, sonogram duration was likely to be longer in the POCUS-R group (n = 13) relative to the POCUS group (16) hazard ratio 0.43 (95% CI, 0.9 to 0.2; P = .03). Whether the final diagnosis was included in the differential diagnosis list, number of diagnoses in the differential list and survival were not different between groups. Educational benefits were the most frequently mentioned benefit by clinician users while logistical and technical problems related to the use of the equipment and inconvenience of enrollment in the study was the most common negative aspect. Teleultrasound was generally not well adopted by users likely due to inconvenience and time constraints. Further work is indicated to assess differences in clinical outcomes in a setting that would allow a larger sample size to increase statistical power.

In vitro and in vivo antiviral effects of CLEVir-X against porcine reproductive and respiratory syndrome virus

The aim of this study was to investigate the in vitro and in vivo antiviral effects of CLEVir-X, against porcine reproductive and respiratory syndrome virus (PRRSV). CLEVir-X is a nucleoside analogue and a dialdehyde form of xanthosine. CLEVir-X demonstrated antiviral action during the in vitro portion of this experiment with its inosine monophosphate dehydrogenase (IMPDH) inhibition against PRRSV. The anti-PRRSV effect of CLEVir-X was recovered through supplementation with guanosine. This suggests that PRRSV replication may be regulated through IMPDH and its guanosine biosynthetic pathway. CLEVir-X treatment in cultures resulted in mutation frequency increase of up to 7.8-fold within the viral genomes (e.g. ORF6) compared to their parallel, untreated cultures. The incorporation of CLEVir-X into the viral genome causes lethal mutagenesis and subsequent decrease in specific infectivity. During the in vivo antiviral experiment, 21-day-old pigs began oral administration of 5 mL of phosphate buffered saline containing CLEVir-X (with purity of 68 % and dosage of 40 mg/kg body weight). This treatment was provided twice daily at 9:00AM and 5:00PM for 14 days. Pigs were simultaneously intranasally inoculated with PRRSV at the beginning of CLEVir-X treatment (21 days of age). Several beneficial effects from the oral administration of CLEVir-X were observed including reduction of body temperature, alleviation of respiratory clinical signs, decreased PRRSV load in both blood and lung tissues, and mitigation of lung interstitial pneumonia lesions. The results of the present study demonstrated that CLEVir-X has mutagenic and nonmutagenic modes of antiviral action against PRRSV based on both in vitro and in vivo antiviral experiments.

Efficacy of Bravecto® Plus spot-on solution for cats (280 mg/ml fluralaner and 14 mg/ml moxidectin) in the prevention of feline Aelurostrongylus abstrusus infection evaluated in a multi-diagnostic approach

BackgroundAelurostrongylus abstrusus is one of the most important respiratory nematodes of felines. Infections may lead to respiratory clinical signs with varying severity or even death, emphasizing the need for preventive treatment of cats with outdoor access to circumvent patent infections.MethodsTherefore, the preventive efficacy of a spot-on formulation of 280 mg/ml fluralaner and 14 mg/ml moxidectin (Bravecto® Plus spot-on solution for cats, MSD) against A. abstrusus was evaluated in a negative controlled, randomized and partially blinded efficacy study with 28 purpose-bred cats in a non-terminal design. In three different treatment regimes, the minimum recommended dose of 40 mg fluralaner and 2.0 mg moxidectin/kg bodyweight (BW) was administered once at 12, 8 or 4 weeks (study group G1, G2 and G3, respectively) prior to experimental infection with 300 third-stage A. abstrusus larvae, while G4 served as placebo-treated control.ResultsFrom 30 to 46 days post infection (dpi; SD 114 to 130), faeces were sampled to monitor first-stage larvae (L1) excretion for efficacy determination. Secondary efficacy criteria, including respiratory parameters, serological antibody levels and computed tomography (CT) findings, were assessed once before enrolment (SD −7 to −1) and before infection (SD 75 to 83). After infection, CT evaluation was performed once at 47–50 dpi (SD 131 to 134), and respiratory parameters and antibody levels were regularly assessed twice or once a week, respectively (1 up to 78 dpi, SD 85 up to 162). All animals in the control group excreted L1 by 33–37 dpi and remained positive throughout the study period from 41 to 46 dpi (SD 125 to 130). In the treatment groups, only one animal each of G1 and G2 excreted L1 at two consecutive days, and four cats of G1, two of G2 and three of G3 were positive on single occasions. While the geometric mean (GM) of the maximum number of excreted L1 per 5 g of faeces was 7380.89 in the control group (G4), GMs were significantly lower in the treatment groups with 1.63 in G1, 1.37 in G2 and 0.79 in G3. Thus, based on GMs, the reduction in excreted L1 exceeded 99.9% in all three treatment groups. Based on CT severity scores, all lungs of the animals of the control group showed severe pulmonary changes post infection, whereas lungs of the cats of the treatment groups were either unaltered (4 animals), mildly (11 animals), or moderately altered (5 animals). Moreover, seroconversion was observed in all cats of the control group, but not in those of the treatment groups.ConclusionsThe combination of diagnostic methods used in this non-terminal study yielded coherent and reliable results. A single administration of Bravecto® Plus spot-on solution for cats was well tolerated and effective in the prevention of aelurostrongylosis for at least 12 weeks.Graphical

Serological Profile for Major Respiratory Viruses in Unvaccinated Cows from High-Yielding Dairy Herds.

This study aims to determine the serological profile of high-yielding dairy cows for four main viruses (bovine alphaherpesvirus 1 (BoAHV1), bovine viral diarrhea virus (BVDV), bovine parainfluenza virus 3 (BPIV3), and bovine respiratory syncytial virus (BRSV)) related to bovine respiratory disease (BRD) in cattle herds worldwide. In this survey, 497 blood serum samples were collected from non-vaccinated dairy cows without clinical respiratory signs in 39 herds in the central-eastern mesoregion of Paraná State, South Brazil. The presence of neutralizing antibodies was determined by virus neutralization (VN) tests. VN antibodies against BoAHV1, BVDV, BPIV3, and BRSV were detected in 355 (71.4%), 280 (56.3%), 481 (96.8%), and 315 (63.4%) serum samples, respectively. The frequencies of seropositive herds for BoAHV1, BVDV, BPIV3, and BRSV were 79.5 (n = 31), 82.0 (n = 32), 100 (n = 39), and 84.6% (n = 33), respectively. The frequencies of seropositive cows varied according to the type of herd management and the number of cows in the herd. The detection of VN antibodies in unvaccinated dairy cattle herds demonstrated the endemic circulation of the four viruses in the herds evaluated. For BRD prevention, it is recommended to implement a vaccination program for cows that provides passive immunity in calves and active immunity in cows.

The Effect of Colostrum Supplementation during the First 5 Days of Life on Calf Health, Enteric Pathogen Shedding, and Immunological Response.

The objective of this dairy farm study was to investigate the preweaning health, performance, immunity, and enteric pathogen shedding in calves supplemented with colostrum during five days after birth compared to calves not supplemented with colostrum. The colostrum supplementation was the previously frozen colostrum added to the milk replacer from day 2-5 given to 39 calves, and 36 Control calves received a milk-derived supplement. There was no significant difference in preweaning weight gain between the treatment groups. Serum samples collected on days 2, 7, 14, and 21 indicated that total and antigen-specific IgG levels against rotavirus, coronavirus, and E. coli F5 were not significantly different between the treatment groups. Fecal samples taken on days 7, 14, and 21 were all negative for coronavirus and E. coli F5, whereas there were low levels of Cryptosporidia and a trend for low levels of rotavirus on day 14 in colostrum-supplemented compared to Control calves. Respiratory clinical signs, depressed attitude and body temperature tended to be reduced in colostrum-supplemented compared to Control calves. This study shows that, even in calves with good colostrum status and high plane of nutrition, there can be benefits of post-closure colostrum supplementation including reduced Cryptosporidia and rotavirus shedding and reduced respiratory disease.

Relationships between pig farm management and facilities and lung lesions' scores and between lung lesions scores and carcass characteristics

BackgroundThe objective of this study was to examine the inter-relationships between pig farm management and facilities (as assessed by questionnaire) and post-mortem lung lesion (lung score assesment), which are the result of respiratory infections. The relationships between carcass characteristics and post-mortem lung lesion scores were also investigated.ResultsQuestionnaire responses were collected from 22 self-selecting pig farmers about their farm facilities/management and health condition of the respiratory system of pigs, including the occurrence of clinical respiratory signs, results of laboratory testing for respiratory pathogens, and the use of respiratory vaccines. When fatteners were sent to the abattoir, their carcasses (n = 1,976) were examined for evidence of respiratory disease by lung lesion (pleuritis pneumonia-like (PP-like) and enzootic pneumonia-like (EP-like) lesions) scoring and the Actinobacillus pleuropneumoniae Index (APPI) was calculated. Carcass characteristics were recorded and, retrospectively, the prevalence of cachectic pigs was calculated. Using these variables, the relationships between farm facilities/management and lung lesions scores and the relationships between the latter and carcass characteristics and cachexia were explored. The key findings relating farm facilities and management to lung lesions were: slatted floors were associated with significantly higher EP-like lesions scores than litter bedding in weaners, single-stage fattening in the same building was associated with significantly higher EP-like lesions scores than two-stage fattening, but herd size, stocking density, use of all-in/all-out (AIAO) rule, technological break duration and variation in daily temperature did not affect lung lesions scores. The key findings relating lung lesion scores to carcass characteristics were: a significant, negative correlation between EP-like scores and carcass weight but not with other carcass characteristics, a significant positive correlation between PP-like scores and carcass meat content and prevalence of cachectic carcasses and a significant positive correlation between lung APPI and prevalence of cachectic carcasses.ConclusionsIt can be concluded that both farm facilities and management affect lung lesions scores and that the latter affect carcass characteristics. Lung lesion scoring is an inexpensive technique suitable for rapid monitoring of large numbers of carcasses that can be performed after animal slaughter. It provides useful information to inform producers about possible deficits in farm facilities or management and is a predictor of economic loss due to poorer quality carcasses.

Association of clinical respiratory disease signs and lower respiratory tract bacterial pathogens with systemic inflammatory response in preweaning dairy calves

This study investigated the potential associations between 3 acute phase proteins (APP)-haptoglobin, serum amyloid A-and fibrinogen, clinical signs of respiratory disease, and the presence of bacterial pathogens in the lower respiratory tract (LRT) of preweaning dairy calves. This cross-sectional study included 150 preweaning calves (2-86 d old) from 15 large dairy herds in Estonia. Tracheobronchial lavage, blood, and fecal samples were collected from 5 calves showing clinical signs indicative of LRT disease, and samples from 5 calves without clinical signs of LRT disease per herd. All samples collected from these calves were analyzed for concentrations of systemic APP, LRT bacteria, and intestinal pathogens. Heifer blood and bulk tank milk samples were collected for the detection of disease-specific antibodies against bovine herpesvirus 1, bovine viral diarrhea virus, bovine respiratory syncytial virus, and Mycoplasma bovis. Mixed-effects linear regression models were used to analyze the associations of clinical respiratory disease signs and LRT bacteria with APP. Increased plasma fibrinogen concentrations in calves were associated with higher rectal temperature (>39.5°C), increased respiratory rate (>50 breaths/min), and coughing. Increased serum amyloid A concentrations were associated with higher rectal temperature (>39.5°C) and respiratory rate between 40 and 50 breaths/min. Calves with the presence of fecal Cryptosporidium spp. and rectal temperature of 39°C and above had increased serum haptoglobin concentrations. Increased fibrinogen concentrations were associated with the presence of Pasteurella multocida in the calf LRT, whereas increased concentrations of fibrinogen and serum amyloid A were associated with the presence of Trueperella pyogenes. In conclusion, APP showed variable associations with clinical signs of respiratory disease and LRT bacteria. Plasma fibrinogen concentration could be used as a complementary calf-side test to assess systemic inflammation caused by LRT bacteria such as Pasteurella multocida and Trueperella pyogenes in preweaning dairy calves.

Isolation and pathogenicity comparison of two novel natural recombinant porcine reproductive and respiratory syndrome viruses with different recombination patterns in Southwest China.

Porcine reproductive and respiratory syndrome virus (PRRSV) causes significant economic losses in the swine industry. Frequent mutations and recombinations account for PRRSV immune evasion and the emergence of novel strains. In this study, we isolated and characterized two novel PRRSV-2 strains from Southwest China exhibiting distinct recombination patterns. They were designated SCABTC-202305 and SCABTC-202309. Phylogenetic results indicated that SCABTC-202305 was classified as lineage 8, and SCABTC-202309 was classified as lineage 1.8. Amino acid mutation analysis identified unique amino acid substitutions and deletions in ORF5 and Nsp2 genes. The results of the recombination analysis revealed that SCABTC-202305 is a recombinant with JXA1 as the major parental strain and NADC30 as the minor parental strain. At the same time, SCABTC-202309 is identified as a recombinant with NADC30 as the major parental strain and JXA1 as the minor parental strain. In this study, we infected piglets with SCABTC-202305, SCABTC-202309, or mock inoculum (control) to study the pathogenicity of these isolates. Although both isolated strains were pathogenic, SCABTC-202305-infected piglets exhibited more severe clinical signs and higher mortality, viral load, and antibody response than SCABTC-202309-infected piglets. SCABTC-202305 also caused more extensive lung lesions based on histopathology. Our findings suggest that the divergent pathogenicity observed between the two novel PRRSV isolates may be attributed to variations in the genetic information encoded by specific genomic regions. Elucidating the genetic determinants governing PRRSV virulence and transmissibility will inform efforts to control this devastating swine pathogen.IMPORTANCEPorcine reproductive and respiratory syndrome virus (PRRSV) is one of the most critical pathogens impacting the global swine industry. Frequent mutations and recombinations have made the control of PRRSV increasingly difficult. Following the NADC30-like PRRSV pandemic, recombination events involving PRRSV strains have further increased. We isolated two novel field PRRSV recombinant strains, SCABTC-202305 and SCABTC-202309, exhibiting different recombination patterns and compared their pathogenicity in animal experiments. The isolates caused higher viral loads, persistent fever, marked weight loss, moderate respiratory clinical signs, and severe histopathologic lung lesions in piglets. Elucidating correlations between recombinant regions and pathogenicity in these isolates can inform epidemiologic tracking of emerging strains and investigations into viral adaptive mechanisms underlying PRRSV immunity evasion. Our findings underscore the importance of continued genomic surveillance to curb this economically damaging pathogen.

Case reports involving coinfection with Avibacterium paragallinarum and Ornithobacterium rhinotracheale in broiler chickens and Avibacterium endocarditis in broiler breeding hens in Poland

ABSTRACT The study describes three clinical cases of infection with Avibacterium spp.. In case no. 1, respiratory clinical signs and high mortality (0.7–4.2% daily; total 21.2%) in Ross 308 broiler chickens were shown to be caused by coinfection with sequence type 9 of O. rhinotracheale presumptive serotype A and A. paragallinarum presumptive serotype B. The identical (pulsed-field gel electrophoresis) restriction pattern (pulsotype) of seven A. paragallinarum isolates indicated that infectious coryza in broilers was caused by the same clone. In cases 2 and 3, sudden increased deaths in Ross 308 broiler breeders (especially males) with lesions in the endocardium (valvular or mural endocarditis) were shown to be caused by A. endocarditis. Among nine antibiotics tested, florfenicol was the only antibiotic to which all A. paragallinarum and O. rhinotracheale isolates were susceptible. Out of the eight antibiotics tested, 11 A. endocarditis isolates from both clinical cases of infective endocarditis were susceptible to penicillin, amoxicillin, doxycycline and florfenicol. The A. endocarditis isolates tested in both clinical cases had different PFGE patterns (pulsotypes), but identical within a case. The causes of infectious coryza and infective endocarditis in the cases presented have not been determined. In the prevention of infectious diseases in large-scale livestock farming, it is very important to follow the rules of biosecurity.

Usefulness of combining computed tomography and air sac fluid examination to rule out aspergillosis: case study in two gentoo penguins (Pygoscelis papua) with respiratory clinical signs.

Pulmonary aspergillosis occurring in captive penguins living in zoos and aquariums is a fatal disease owing to its high mortality rate. On conducting computed tomography, two gentoo penguins (Pygoscelis papua) with respiratory clinical signs that were housed at an aquarium in Hokkaido, Japan were found to have a certain amount of fluid in their air sacs. This fluid was collected and cultured for bacteria and fungi, the results of which both came back negative. These results enabled us to rule out bacterial infection or aspergillosis and supported our decision not to administer antibacterial and antifungal drugs. Overall, the combination of computed tomography and air sac fluid examination was useful for ruling out bacterial infection or aspergillosis in penguins with respiratory clinical signs.

Genetic and Pathogenic Characteristics of an Emerging Highly Virulent Recombinant Lineage Korean Clade C PRRSV Strain

A strain of porcine reproductive and respiratory syndrome virus (PRRSV) was isolated from lung tissue of a pig showing severe respiratory clinical signs from a farm in Gyeongsang province of South Korea. This PRRSV strain, designated as SNUVR220803, was classified within the lineage Korean clade C (LKC) based on a phylogenetic analysis of the ORF5 gene. A whole‐genome analysis was conducted on the SNUVR220803 strain, which appears to be a recombinant between the PRRSV strains K07‐2273 (part of LKC lineage) and Ingelvac MLV (part of Lineage 5). The Nsp2 amino acid sequence of this strain features a deletion of four additional amino acids, setting it apart from the typical Korean clades A, B, and C lineages. An animal inoculation experiment was conducted with 24 pigs divided into three groups: 12 pigs in the inoculated group, six in the sentinel group, and six in the negative control group. Inoculated pigs exhibited persisting hyperthermia (≥40.3°C) for 5 days, palpebral edema, and cyanosis. Subsequently, these pigs suffered from severe respiratory distress and cachexia, leading to a mortality rate of 58.3% (7 out of 12 pigs) at 14 days postinoculation (dpi). Body weight decreased post‐SNUVR220803 strain infection in both the inoculated and sentinel groups. Gross pathology revealed noncollapsed lungs and serous effusion in the pericardial and peritoneal cavities. Microscopic analysis revealed severe interstitial pneumonia, while immunohistochemistry confirmed the presence of PRRSV antigen in the lungs, lymph nodes, thymus, kidneys, and the heart. Additionally, the levels of cytokines such as tumor necrosis factor‐α (TNF‐α), interferon‐α (IFN‐α), and IL‐10 were significantly elevated in the plasma of infected pigs. These observations indicate that the LKC recombinant strain, combined with Lineage 5, possesses high virulence and infectivity as characterized by distinctive exudative lesions.

Surveillance of Avian Metapneumovirus in Non-Vaccinated Chickens and Co-Infection with Avian Pathogenic Escherichia coli.

Brazil is the second largest producer of broiler chicken in the world, and the surveillance of avian pathogens is of great importance for the global economy and nutrition. Avian metapneumovirus (aMPV) infection results in high rates of animal carcass losses due to aerosacculitis and these impacts can be worsened through co-infection with pathogenic bacteria, particularly Escherichia coli (APEC). The present study evaluated the seroprevalence of the main aMPV subtypes in unvaccinated broiler chickens from poultry farms in Brazil, as well as the clinical effects of co-infection with APEC. Blood samples, respiratory swabs, femurs, liver, and spleen of post-mortem broiler chickens were collected from 100 poultry production batches, totaling 1000 samples. The selection of the production batch was based on the history of systemic and respiratory clinical signs. The results indicated that 20% of the lots showed serological evidence of the presence of aMPV, with two lots being positive for aMPV-B. A total of 45% of batches demonstrated co-infection between aMPV and APEC. The results point to the need for viral surveillance, targeted vaccination, and vaccination programs, which could reduce clinical problems and consequently reduce the use of antibiotics to treat bacterial co-infections.

Comparative diagnoses of respiratory disease in preweaned dairy calves using sequential thoracic ultrasonography and clinical respiratory scoring.

Bovine respiratory disease (BRD) has serious impacts on dairy production and animal welfare. It is most commonly diagnosed based on clinical respiratory signs (CRS), but in recent years, thoracic ultrasonography (TUS) has emerged as a diagnostic tool with improved sensitivity and specificity. This study aimed to assess the alignment of BRD diagnoses based on a Clinical Respiratory Scoring Chart (CRSC) and weekly TUS findings throughout the progression of BRD of variable severity in preweaned Holstein dairy heifers. A total of 60 calves on two farms were followed from the 2nd week of life through the 11th week of life and assessed on a weekly basis for CRS and lung consolidation via TUS. The alignment of BRD diagnoses based on CRSC scores and TUS findings was evaluated across disease progression (pre-consolidation, onset, chronic, or recovered) and severity (lobular or lobar lung consolidation) using receiver operator curves and area under the curves combined with Cohen's kappa (κ), sensitivity, and specificity. The diagnosis of BRD using CRSC scores ≥5 aligned best with the onset of lobar lung consolidation (>1 cm in width and full thickness). This equated to an acceptable level of discrimination (AUC = 0.76), fair agreement (κ = 0.37), and a sensitivity of 29% and specificity of 99%. Similarly, there was acceptable discrimination (AUC = 0.70) and fair agreement (κ = 0.33) between CRSC ≥5 and the onset of a less severe threshold of disease based on lobular (1-3 cm2 but not full thickness) or lobar consolidation. Discrimination remained acceptable (AUC = 0.71) with fair agreement (κ = 0.28) between CRSC scores ≥2 for nasal discharge and/or cough (spontaneous or induced) and the onset of lobar consolidation. However, sensitivity was <40% across comparisons and outside of the onset of disease there tended to be poor discrimination, slight agreement, and lowered sensitivity between CRS and TUS diagnoses of lobular or lobar consolidation (pre-consolidation, chronic, or recovered). Conversely, specificity was relatively high (≥92%) across comparisons suggesting that CRSC diagnoses indicative of BRD and associated lung consolidation tend to result in few false positive diagnoses and accurate identification of healthy animals. Although we found the specificity of clinical signs for diagnosing lung consolidation to be ≥92% across all methods of TUS evaluations, the low levels of sensitivity dictate that clinical assessments lead to many false negative diagnoses. Consequently, depending on clinical signs alone to diagnose BRD within populations of dairy calves will likely result in overlooking a substantial proportion of subclinically affected animals that could inform the success of treatment and prevention protocols and guide management decisions.

Detection of bovine coronavirus (BCoV) infection in cattle with clinical respiratory signs by PCR and investigation of the serological status of these animals

Aim: It was aimed to reveal the antigenic and serological prevalence of bovine coronavirus (BCoV) in cattle with clinically respiratory infection and to evaluate the relationship between virus shedding and serological status of animals in this study. Materials and Methods: In the study, nasal swab samples were collected from a total of 92 cattle of different gender between 0 and 2 years of age with clinical respiratory symptoms. These samples were subjected to RT-PCR using specific primer pairs. Furthermore, serum samples were also collected from the same animals and evaluated for BCoV-specific antibodies through an indirect ELISA method. Results: Ten (10.87%) swap samples were defined as positive for BCoV using RT-PCR. The seropositivity rate was 93.48% (86/92) in cattle by ELISA and 90% (9/10) in virus-shedding animals with nasal swab samples. Conclusion: The fact that 93.47% seropositivity was detected in unvaccinated animals against coronavirus in this study indicates that the animals were exposed to BCoV through colostrum or at a certain period of their lives. However the fact that 9 out of 10 animals with BCoV detected in swab samples also have BCoV-specific antibodies casts doubt on the efficacy of these antibodies in protecting against respiratory BCoV infections. We concluded that more detailed studies are needed to reveal the role of antibodies in respiratory coronavirus infections.