Retrospective comparison of outcomes in septic peritonitis with or without closed-suction abdominal drainage in 115 dogs (2009-2019).

Septic peritonitis is a serious medical condition affecting veterinary patients and post-operative care remains controversial. This study aimed to evaluate and compare post-operative outcomes of dogs treated for septic peritonitis with and without surgically placed closed-suction abdominal drains. Medical records were retrospectively searched from the years 2009 through 2019 and one hundred and fifteen dogs with confirmed septic peritonitis treated with exploratory laparotomy were included. Twenty-two dogs had closed suction drains placed and ninety-three dogs were managed without post-operative drainage. Overall survival to discharge rate of patients in this study was 72%. The survival rate of patients with an abdominal drain was 53% compared to 77% in patients without a drain (P < 0.0001). Dogs with a higher APPLEfast score were significantly more likely to have a drain placed at the time of surgery (P = 0.0277). Dogs that had a closed-suction drain were significantly more likely to be given colloidal support compared to dogs managed without drainage (P = 0.0342). Based on this data, closed-suction drainage post-operatively for treatment of septic peritonitis was not associated with a more favorable survival outcome. The use of a severity of illness score, APPLEfast, did not show a correlation between severity of illness and survival outcome but did demonstrate a correlation between illness severity and placement of a closed-suction drain. Closed-suction drainage post-operatively increased the likelihood of receiving colloidal support, but due to the retrospective nature of the study and the lack of standardized post-operative nutritional support, definitive conclusion that post-operative drainage alone led to increased colloidal support cannot be made in this study.

Comparison of turbidometric immunoassay, refractometry, and gamma-glutamyl transferase to radial immunodiffusion for assessment of transfer of passive immunity in high-risk beef calves.

BACKGROUND: Attainment of adequate transfer of passive immunity (TPI) is critical to health of calves; however, studies comparing available tools for measurement of TPI in individual beef animals are limited. OBJECTIVES: To report agreement between 4 tests evaluating individual TPI status in beef calves. ANIMALS: One hundred ninety-six beef calves born to cows and heifers presenting for calving management or dystocia. METHODS: Retrospective study to assess serum immunoglobulin (IgG) concentrations via turbidimetric immunoassay (TI), gamma-glutamyl transferase (GGT), serum total protein (TP), and single radial immunodiffusion (RID; reference standard). Test agreement was evaluated using Passing-Bablok regression, Bland-Altman analysis, Cohen's kappa, and receiver operating characteristic (ROC) curves with and without covariate adjustment to determine optimal thresholds. RESULTS: Correlation between RID and test results varied: TI, ρ = 0.757; TP, ρ = 0.715; GGT: ρ = 0.413. For the TI compared to RID, regression analysis identified a constant (intercept = -0.51 [CI: -2.63, 3.05]) and proportional (slope = 1.87 [CI: 1.69, 2.08]) bias. Based on ROC, TI concentrations of ≤9.89 and ≤13.76 g/L, and TP concentrations of ≤5.5 and ≤6.0 g/dL, indicated IgG concentrations <18.0 and <25.0 g/L, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: Within this cohort of calves, TI demonstrated the best correlation with RID; however, significant bias was identified which led to frequent underestimation of IgG concentration. Serum total protein demonstrated less correlation with RID but had less misclassification than TI. Both TI and TP demonstrated less correlation for calves that received colostrum replacement prompting clinical awareness of colostrum type when evaluating individual TPI in beef calves.

Comparison of turbidometric immunoassay and brix refractometry to radial immunodiffusion for assessment of colostral immunoglobulin concentration in beef cattle.

BACKGROUND: Colostral immunoglobulin G (IgG) concentration is critical to the attainment of adequate transfer of passive immunity in cattle, however, studies comparing available tools for measurement of colostral IgG concentration in beef cattle are limited. OBJECTIVES: To report the agreement between 3 commercially available tests for evaluating IgG concentration in beef colostrum. ANIMALS: Two hundred six beef-breed cows hospitalized for calving management or dystocia. METHODS: Retrospective study to assess IgG of whole colostrum measured stall-side via turbidimetric immunoassay (TI) and brix refractometry (BRIX), compared to fat separated (FS) analysis via single radial-immunodiffusion (RID; reference standard), TI-FS and BRIX-FS. Test performance was assessed using Passing Bablock regression, Bland-Altman analysis, and area under the curve to determine optimal thresholds. RESULTS: Correlation between RID and TI-FS, BRIX-FS, or BRIX was similar (Spearman's ρ = 0.717, 0.715, 0.716, respectively) but correlation for TI was poor (ρ = 0.586). Regression analysis identified a substantial constant (-214.75 [CI: -272.03 to -178.07]) and proportional (13.24 [CI: 11.81-15.37]) bias between the RID and TI-FS which was similar for TI. TI-FS concentrations of 28.47, 38.75, and 50.62 g/L, BRIX-FS of ≤21.9%, ≤24.0%, and ≤27.4%, and BRIX of ≤21.3%, ≤23.8%, and ≤26.4% indicated IgG concentrations <50, <100, and <150 g/L, respectively; appropriate cutoffs for TI could not be generated. CONCLUSIONS AND CLINICAL IMPORTANCE: Both TI and TI-FS demonstrated a large constant and proportional bias compared to RID; BRIX and BRIX-FS were well correlated with RID and remain a reliable method for estimation of colostral IgG concentration in beef cattle.

Connecting a disconnected trial network with a new trial: optimizing the estimation of a comparative effect in a network meta-analysis.

BACKGROUND: In network meta-analysis, estimation of a comparative effect can be performed for treatments that are connected either directly or indirectly. However, disconnected trial networks may arise, which poses a challenge to comparing all available treatments of interest. Several modeling approaches attempt to compare treatments from disconnected networks but not without strong assumptions and limitations. Conducting a new trial to connect a disconnected network can enable calculation of all treatment comparisons and help researchers maximize the value of the existing networks. Here, we develop an approach to finding the best connecting trial given a specific comparison of interest. METHODS: We present formulas to quantify the variation in the estimation of a particular comparative effect of interest for any possible connecting two-arm trial. We propose a procedure to identify the optimal connecting trial that minimizes this variation in effect estimation. RESULTS: We show that connecting two treatments indirectly might be preferred to direct connection through a new trial, by leveraging information from the existing disconnected networks. Using a real network of studies on the use of vaccines in the treatment of bovine respiratory disease (BRD), we illustrate a procedure to identify the best connecting trial and confirm our findings via simulation. CONCLUSION: Researchers wishing to conduct a connecting two-arm study can use the procedure provided here to identify the best connecting trial. The choice of trial that minimizes the variance of a comparison of interest is network dependent and it is possible that connecting treatments indirectly may be preferred to direct connection.

Comparison of Two Diagnostic Assays for the Detection of Serum Neutralizing Antibody to Porcine Epidemic Diarrhea Virus.

Lactogenic immunity is important for the protection of piglets against many pathogens including porcine epidemic diarrhea virus. Circulating neutralizing antibodies levels in sow sera may help determine if a detectable immune response could confer protection to piglets. Neutralizing antibodies can be detected through various diagnostic assays. This study evaluated the diagnostic characteristics of two neutralizing antibody assays for porcine epidemic diarrhea virus neutralizing antibodies in serum of challenged gilts. Four treatment groups, control, non-vaccinated, vaccinated prior to challenge, and vaccinated following challenge, were comprised of 20 gilts. Serum sample were collected from each gilt prior to and following challenge with porcine epidemic diarrhea virus. Samples were evaluated for the presence of neutralizing antibodies via a fluorescent focus neutralization assay and a high-throughput neutralization assay. Diagnostic sensitivity and specificity for the fluorescent focus neutralization and high-throughput neutralization assays for this study were optimized at a cutoff of a dilution of 80 and 80% fluorescent reduction respectively and demonstrated moderate agreement based off the kappa statistic. The focus fluorescent neutralization and high-throughput neutralization assays can be used to monitor the status of neutralizing antibodies within animals or a population of animals. The high-throughput assay has advantages over the focus fluorescent assay in that it has a higher specificity at the indicated cut-off and the nature of the results allows for more discrimination between individual results.

Evaluation of the intranasal route for porcine reproductive and respiratory disease modified-live virus vaccination.

BACKGROUND: In pigs, modified live virus (MLV) vaccines against porcine reproductive and respiratory syndrome virus (PRRSV) are commonly used and administered by intramuscular (IM) injection. In contrast, PRRSV, as a primary respiratory pathogen, is mainly transmitted via the intranasal (IN) route. The objective of this study was to evaluate the efficacy of a commonly used commercial PRRSV MLV delivered IN compared to the IM route. METHODS: Fifty-four pigs were divided into five treatment groups. All vaccinated groups received the same MLV vaccine but administered via different routes. Group IN-JET-VAC was vaccinated with an automated high pressure prototype nasal jet device (IN-JET-VAC, n = 12), group IN-MAD-VAC was vaccinated with a mucosal atomization device (IN-MAD-VAC, n = 12), group IM-VAC was vaccinated intramuscularly (IM-VAC; n = 12) according to label instructions, while the NEG-CONTROL (n = 6) and the POS-CONTROL (n = 12) groups were both unvaccinated. At 28 days post vaccination all vaccinated groups and the POS-CONTROL pigs were challenged with a pathogenic US PRRSV isolate. Blood and nasal swabs were collected at regular intervals, and all pigs were necropsied at day 10 post challenge (dpc) when gross and microscopic lung lesions were assessed. RESULTS: Prior to challenge most vaccinated pigs had seroconverted to PRRSV. Clinical signs (fever, inappetence) were most obvious in the POS-CONTROL group from dpc 7 onwards. The vaccinated groups were not different for PRRSV viremia, seroconversion, or average daily weight gain. However, IN-JET-VAC and IN-MAD-VAC had significantly higher neutralizing antibody levels against the vaccine virus at challenge. CONCLUSIONS: Comparable vaccine responses were obtained in IN and IM vaccinated pigs, suggesting the intranasal administration route as an alternative option for PRRSV vaccination.

Disinfection and conditions associated with thermo-assisted drying and decontamination inconsistently produce negative PRRSV rRT-PCR results on metal surfaces.

Because contaminated livestock trailers are a significant risk for transmitting viruses between herds, various methods of washing, disinfecting, and thermo-assisted drying and decontamination (TADD) have been evaluated for their effectiveness in inactivating porcine reproductive and respiratory syndrome virus (PRRSV) on contaminated surfaces. Information on when to expect negative qRT-PCR results after adequate trailer sanitation is lacking. The objective of this study was to evaluate whether there are conditions associated with washing-disinfectant-TADD procedures that will consistently produce a negative qRT-PCR result for the purpose of monitoring compliance with trailer sanitation and decontamination protocols for PRRSV on metal surfaces. 144 diamond plate aluminum coupons were spiked with PRRSV or phosphate-buffered saline (PBS) and treated with a designated disinfectant protocol. Disinfectants evaluated included multiple accelerated® hydrogen peroxide (AHP) disinfectants and a quaternary ammonium and glutaraldehyde combination disinfectant. Disinfectant was applied for 5 or 60 minutes of contact time at either 20 °C or -10 °C in a matrix of feces or PBS. All coupons were heated until the surface temperature of the coupon reached 71 °C and then held for 10 minutes to simulate TADD under field conditions. Post-treatment swabs for all treatment groups, except negative control groups, were positive by PRRSV qRT-PCR. Under the conditions evaluated in this study, consistently negative qRT-PCR results after treatments were not found. Therefore, for the purpose of monitoring compliance with trailer sanitation and decontamination protocols for PRRSV, alternatives to qRT-PCR should be explored.

Chikungunya in Guerrero, Mexico, 2019 and Evidence of Gross Underreporting in the Region.

The local public health authorities reported nine cases of chikungunya in Mexico in 2019, none of which occurred in Guerrero, a coastal state in the southwest. To test the hypothesis that chikungunya is grossly underreported in Mexico, acute sera were collected from 639 febrile patients from low-income households in Guerrero in 2019 and serologically assayed for chikungunya virus (CHIKV). Analysis of the sera by plaque reduction neutralization test revealed that 181 (28.3%) patients were seropositive for CHIKV. To identify patients with acute CHIKV infections, a subset of serum samples were tested for CHIKV-specific IgM by ELISA. Serum samples from 21 of 189 (11.1%) patients were positive. These patients met the chikungunya case definition established by the WHO. In conclusion, we provide evidence that CHIKV remains an important public health problem in Mexico and that the true number of cases is severely underestimated.

Co-Circulation of All Four Dengue Viruses and Zika Virus in Guerrero, Mexico, 2019.

A clinical and entomological investigation was performed to identify flavivirus infections in humans and mosquitoes in impoverished areas of Guerrero, a coastal state in southwestern Mexico. A total of 639 patients with acute febrile illness and 830 resting female mosquitoes in low-income communities of Guerrero in 2019 were tested for evidence of flavivirus infection. Sera were collected from all patients and screened at a dilution of 1:20 by plaque reduction neutralization test (PRNT) using dengue virus (DENV)2. A total of 431 (67.4%) patients were seropositive. Sera from a subset of seropositive patients (n = 263) were tested for flavivirus NS1 by enzyme-linked immunosorbent assay. Forty-eight (18.3%) sera contained viral antigen. All NS1-positive sera were titrated and further tested by PRNT using DENV-1 to -4, St. Louis encephalitis virus, West Nile virus, and Zika virus (ZIKV). Seven patients were seropositive for DENV-1, five patients were seropositive for DENV-2, one patient was seropositive for DENV-3, and two patients each were seropositive for DENV-4 and ZIKV. The remainder had secondary flavivirus infections or antibodies to an undetermined flavivirus. Comparative PRNTs were also performed on 60 randomly selected NS1-negative sera, identifying patients seropositive for DENV-2, DENV-3, and ZIKV. The entomological investigation yielded 736 Aedes aegypti and 94 Culex quinquefasciatus that were sorted into 183 pools and 20 pools, respectively. Mosquitoes were assayed for flavivirus RNA by RT-PCR and Sanger sequencing. DENV-2 RNA was detected in three pools of A. aegypti. In summary, we provide evidence for the concurrent circulation of all four DENVs and ZIKV in Guerrero, Mexico. The public health authorities reported no cases of DENV-3, DENV-4, and ZIKV in Guerrero in 2019 and thus, we provide evidence of under-reporting in the region.