To further characterize the humoral immune response of pigs to porcine reproductive and respiratory syndrome virus (PRRSV), direct enzyme-linked immunosorbent assays (ELISA) were used to study the kinetics of antibody responses directed against PRRSV nonstructural proteins in pigs experimentally exposed to the virus. The highest immunoreactivities were against nsp1, nsp2, and nsp7. Using the recombinant nsp7 as an antigen, we validated a dual ELISA for the simultaneous detection and differentiation of serum antibodies against type I and type II PRRSV. Receiver operating characteristic analysis based on 1,334 known-positive and 1,357 known-negative samples showed good specificity (98.3% to type I and 99.3% to type II) and sensitivity (97.4% for type I and 99.8% for type II). To differentiate type I and type II PRRSV, 470 sera originating from experimentally inoculated pigs were tested, and positive sera were correctly differentiated in 469 of 470 samples. The capability of the nsp7 dual ELISA to detect serum antibody responses from pigs infected with various genetically different field strains was determined. The nsp7 dual ELISA possessed 97.6% agreement with the Idexx HerdChek PRRS 2XR ELISA. In further testing of Idexx ELISA suspected false-positive samples, the nsp7 dual ELISA resolved 98% of the samples as negative. Taken together, these results indicate that the nsp7 dual ELISA can be used as a differential test for PRRSV serology with high levels of sensitivity and specificity. This ELISA offers an additional tool for routine or follow-up diagnostics, as well as having substantial value in epidemiological surveys and outbreak investigations.

Infection with porcine reproductive and respiratory syndrome virus (PRRSV) results in a weak antiviral immune response that leads to a persistent infection in a subset of pigs. We investigated the intensity and timing of the early cytokine responses to PRRSV infection to determine their utility as a predictor of persistence. As part of the ''Big Pig'' project, we evaluated cytokine gene expression in lymphoid tissues collected from pigs for up 202 days post-infection (dpi); serum samples were collected biweekly. Cytokine mRNA levels were compared between pigs that cleared the viral infection from serum and tissues (non-persistent [NP] pigs) to those of persistent (P) pigs, that had viral RNA in their serum for up to 126 dpi. The gene expression studies in the tracheobronchial lymph nodes (TBLN) of all the pigs showed upregulation of interferon-g (IFN-g)-associated T-helper 1 (Th-1) markers from 14-84 dpi, and of T-regulatory interleukin-10 (IL-10), but no upregulation of innate markers (IFN-A, IL-1B, and IL-8). At later time points (>112 dpi) these genes were no longer differentially expressed and thus were uninformative for persistence studies. Statistical analyses of serum cytokine levels indicated that innate cytokine (IL-1b and IL-8) levels were upregulated early after infection. Interestingly, serum IL-8 levels in NP pigs were significantly higher than in P pigs at 14 dpi. When analyzed together, variations in all three of the serum cytokines tested (IL-8, IL-1b, and IFN-g) was significantly correlated with virus level, accounting for *84% of the variations observed. These results indicate that while each cytokine individually has minor effects on the length of virus replication, the combination of cytokine activities should be considered when understanding the role of immunity in persistence.

No abstract

BackgroundChagas disease is an important health problem in Latin America due to its incapacitating effects and associated mortality. Studies on seropositivity for Trypanosoma cruzi in Mexican dogs have demonstrated a direct correlation between seropositivity in humans and dogs, which can act as sentinels for the disease in this region. The objective of this study was to determine the seropositivity for T.cruzi infection in dogs from Sonora, a northern borderstate of Mexico.MethodsResponsible pet owners were selected at random from an urban area of Empalme municipality, Sonora, Mexico, and from there, 180 dog samples were collected. Anti-T. cruzi antibodies were determined using the enzyme-linked immunosorbent assay (ELISA) method. Reactive ELISA sera were processed by indirect immunofluorescence to confirm the presence of anti-T. cruzi antibodies. For the statistical analysis, chi-square tests were conducted.ResultsDogs’ sera showed a seropositivity rate of 4.44%. The rate of seropositivity was not associated with the dogs’ age, sex, or socioeconomics pertaining to the geographical area. One sample (1/180, 0.55%) showed the acute state of the disease.ConclusionsThe study found a presence of anti-T. cruzi antibodies in dogs in this area, which suggests vector transmission. There is a need for active surveillance programs throughout the state of Sonora and vector control strategies should also be implemented in endemic regions.

Abstract. Three assays were evaluated for their ability to detect antibodies against Porcine reproductive and respiratory syndrome virus (PRRSV) in porcine muscle transudate (''meat juice'') samples. Samples were derived from 91 pigs inoculated with PRRSV isolate VR-2332 and 46 age-matched controls. Serum and muscle (Musculus longissimus dorsi) samples were collected from randomly selected animals euthanized at ,14-day intervals from 28 to 202 days postinoculation. Serum samples were assayed at a dilution of 1:40, and muscle transudate samples were assayed at 5 dilutions (1:2, 1:5, 1:10, 1:20, 1:40) using a commercial PRRSV antibody enzyme-linked immunosorbent assay (ELISA). In addition, muscle transudate samples were tested using an indirect fluorescent antibody test (IFAT) at 5 dilutions (1:2, 1:5, 1:10, 1:20, 1:40). Attempts to assay muscle transudate samples for neutralizing antibodies using a modified fluorescent focus neutralization assay were unsuccessful. Receiver operator characteristic (ROC) curve analyses were used to estimate cutoff thresholds and the associated diagnostic sensitivities and specificities for ELISA and IFAT at each dilution. For ELISA, muscle transudate samples at the ROC-optimized cutoffs were .95% sensitive and 100% specific at each dilution. At a cutoff dilution of $1:5, the IFAT diagnostic sensitivity and specificity of muscle transudate was estimated at 63.3% and 100%, respectively. These findings validated the use of muscle transudate samples in PRRSV surveillance programs based on ELISA antibody testing.

RESUMENSe consiguieron identificar 23 aislamientos de Gallibacterium anatis, a través de pruebas convencionales de cultivo y bioquímicas, confirmándose su identificación a través del método de PCR. Se les efectuó la prueba de difusión en placa para determinar la resistencia antimicrobiana a los antibióticos más utilizados en el área avícola. Los aislamientos fueron más susceptibles a ceftiofur (73 %) y florfenicol (68 %); todos los aislamientos mostraron resistencia marcada a penicilina, tilosina, lincomicina, ampicilina, enrofloxacina, oxitetraciclina, norfloxacina y cefalexina. La presencia de Gallibacterium anatis se asocia a problemas respiratorios y reproductivos en las poblaciones de gallinas de postura comercial. Los aislamientos mostraron una resistencia marcada a distintos antibióticos, probablemente por la medicación desmedida ante la presencia de este microorganismo. PALABRAS CLAVE: Gallibacterium anatis, PCR, Resistencia, Susceptibilidad, Antimicrobianos. ABSTRACTIt was able to identify 23 isolates of Gallibacterium anatis through conventional culture and biochemical tests, and identification confirmed through PCR method. A disk diffusion test determined antimicrobial resistance to commonly used antibiotics in the poultry area. Isolates were more susceptible to ceftiofur (73 %) and florfenicol (68 %). All isolates showed marked resistance to penicillin, tylosin, lincomycin, ampicillin, enrofloxacin, oxytetracycline, norfloxacin and cephalexin. The presence of Gallibacterium anatis is associated with respiratory and reproductive problems in populations of commercial laying hens. Isolates showed marked resistance to different antibiotics, probably due to excessive medication in the presence of this organism.

The objectives of this experiment were to determine how long porcine reproductive and respiratory syndrome virus (PRRSV) could be detected in muscle tissues of experimentally infected pigs and to evaluate the transmissibility of PRRSV to pigs via ingestion of quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR)-positive muscle tissues. Serum, lymphoid tissues, and muscle (M. longissimus dorsi) samples were collected from 135 pigs (89 PRRSV-inoculated pigs and 46 negative control). Between 28 and 202 days post-inoculation, 13 of 89 (14.6%) muscle samples were positive by qRT-PCR. Among these 13, PRRSV was isolated from four of the 13 corresponding serum samples and three of 13 lymphoid tissue samples. In addition, infectious virus was detected in lymphoid tissue homogenates of six of 13 pigs by intramuscular bioassay. Swine transmissibility studies were performed by feeding thirteen 3-week-old PRRSV-naive pigs (recipient pigs) qRT-PCR-positive muscle and then monitoring recipients for evidence of PRRSV viremia by qRT-PCR. No transmission of PRRSV to recipient pigs via consumption of muscle samples was observed. These data suggested that qRT-PCR detected non-infectious PRRSV in pig meat and/or PRRSV is not highly transmissible to susceptible pigs via consumption of PRRSV-contaminated meat.

This investigation was carried out to determine the effect of Essential Fatty Acids proportion (EFAs [n-6, n-3]) in feed through the mixture of soy, olive, canola or chia oil on EFA profile in eggs as well as productive and reproductive performance of Japanese quail. We used 120 quail from 7 to 22 weeks of age, in 15 cages in groups of 6 females and 2 males assigned according to the completely randomized design to 3 treatments with 5 replicates. The treatments were n-6:n-3 proportions 10:1 (control), 4:1 and 1:1. FA profile in yolk, feed intake, laying rate, egg weight, fertility, hatchability, and embryonic mortality were measured. In the egg yolk, n-6 content was similar in the proportions (p>0.05), while n-3 content increased (p<0.01) as n-6:n-3 ratio decreased in the feed. Feed consumption per quail was similar between treatments (p>0.05). In 4:1 and 1:1 proportion laying percentage was greater, but egg weight was lower (p<0.01). Fertility and hatchability were similar between proportions n-6, n-3 (p>0.68). Early and total embryonic mortality was lower in 10:1 and 4:1 proportion (p<0.01); while intermediate and late mortality was similar (p>0.30). The results of the experiment indicate that the mixture of soy, olive, canola or chia oil, to obtain n-6:n-3 proportion of 1:1, 4:1 and 10:1 does not modify feed consumption, laying rate, egg weight, fertility, and hatchability; but, 4:1 and 10:1 proportions favor a lower embryonic mortality.