EC30-39 Swine Sanitation

From the very beginning of Nebraska's agricultural development its farmers have recognized that the production of swine must of necessity accompany the growing of corn. The latter, one of the state's most important staples, cannot be marketed in a more economical manner than after having been transformed into pork, bacon, and lard. As a result the state has for many years maintained a rather dense swine population mainly divided into large herds kept on relatively small areas of land. This density of population, as well as certain practices in management and selective breeding, has brought about conditions favorable for the propagation of a number of microbic or parasitic diseases which, in a costly manner, force themselves to our attention. The various factors which affect the incidence of swine diseases are numerous and in a given situtation may be so intricately interwoven as to baffle the observer. This extension circular discusses these factors and how to prevent the spread throughout the swine population.

Seroprevalence of equine influenza virus in northeast and southern Mexico

EQUINE influenza A virus (EIV) is a highly infectious respiratory pathogen of horses (Hannant and Mumford 1996, Palese and Shaw 2007). The illness is characterized by an abrupt onset of fever, depression, coughing and nasal discharge, and is often complicated by secondary bacterial infections that can lead to pneumonia and death. Two subtypes of EIV, H3N8 and H7N7, have been isolated. The H7N7 subtype was first isolated from a horse in Czechoslovakia in 1956 (Prague/56), and the H3N8 subtype was first isolated from a horse in Miami in 1963 (Sovinova and others 1958, Waddell and others 1963). The last confirmed outbreak of H7N7 occurred in 1979, and this subtype is now considered to be either extinct or circulating at low levels in a few geographical areas (Ismail and others 1990, Webster 1993, Singh 1994, Madic and others 1996, van Maanen and Cullinane 2002). The H3N8 subtype is a common cause of disease in horses worldwide, particularly in areas where vaccination is not routinely performed (Paillot and others 2006).

A Field-Test of Rhodamine B as a Biomarker in Raccoons

Rhodamine B is a dye that when ingested results in fluorescent bands in growing hair and whiskers of many mammals. Previous research at Wildlife Services’ (WS) National Wildlife Research Center (NWRC) found that rhodamine B is a successful biomarker in raccoon whiskers and that raccoons do not have a taste aversion to the dye when it comprises ≤ 3% of a bait. Our study assessed the ease of bait distribution, whisker collection, and evaluation of the biomarker for potential use in the Oral Rabies Vaccination (ORV) program administered by the WS National Rabies Management Program (NRMP). In collaboration with WS operations personnel from Ohio and Michigan, 750 fishmeal polymer baits each containing 150 mg of rhodamine B were hand distributed at NASA’s Plum Brook Station, Sandusky, Ohio in the summer of 2008. Four weeks after baits were distributed whiskers from 162 raccoons were collected. Wildlife Services biologists and technicians evaluated the whiskers for fluorescence using a handheld UV magnifying lamp. Biologists then sent the whiskers to the NWRC, Ft. Collins, Colorado for confirmation of fluorescence under a UV microscope. Results suggest a high level of agreement between the two methods of evaluation. Surveys completed by biologists confirmed that the ease of use, less invasive sampling techniques and promptness of results obtained through the use of rhodamine B are advantageous to the tetracycline biomarker presently used by the ORV program. All participants recommended further evaluation of rhodamine B for its inclusion in future efforts requiring biomarker evaluation.

PREVALENCE AND DETERMINANTS OF EXCLUSIVE BREASTFEEDING IN THE CITY OF SERRANA, SAO PAULO, BRAZIL

The objective of this cross-sectional and quantitative study was to identify the prevalence and determinants of exclusive breastfeeding among infants less than six months of age in the city of Serrana, Sao Paulo, Brazil in 2009. A validated semi-structured questionnaire was administered to the guardians of the children less than six months of age who attended the second phase of a Brazilian vaccination campaign against polio. Univariate and multivariate analysis presented in odds ratios and confidence intervals was accomplished. Of the total of 275 infant participants, only 29.8% were exclusively breastfed. Univariate analysis revealed that mothers who work outside the home without maternity leave, mothers who did not work outside the home, adolescent mothers, and the use of pacifiers have a greater chance of interrupting exclusive breastfeeding. In the multivariate analysis, mothers who work outside the home without maternity leave are three times more likely to wean their children early. Results provide suggestions for the redirection and planning of interventions targeting breastfeeding.

On estimating the basic reproduction number in distinct stages of a contagious disease spreading

In epidemiology, the basic reproduction number R-0 is usually defined as the average number of new infections caused by a single infective individual introduced into a completely susceptible population. According to this definition. R-0 is related to the initial stage of the spreading of a contagious disease. However, from epidemiological models based on ordinary differential equations (ODE), R-0 is commonly derived from a linear stability analysis and interpreted as a bifurcation parameter: typically, when R-0 >1, the contagious disease tends to persist in the population because the endemic stationary solution is asymptotically stable: when R-0 <1, the corresponding pathogen tends to naturally disappear because the disease-free stationary solution is asymptotically stable. Here we intend to answer the following question: Do these two different approaches for calculating R-0 give the same numerical values? In other words, is the number of secondary infections caused by a unique sick individual equal to the threshold obtained from stability analysis of steady states of ODE? For finding the answer, we use a susceptibleinfective-recovered (SIR) model described in terms of ODE and also in terms of a probabilistic cellular automaton (PCA), where each individual (corresponding to a cell of the PCA lattice) is connected to others by a random network favoring local contacts. The values of R-0 obtained from both approaches are compared, showing good agreement. (C) 2012 Elsevier B.V. All rights reserved.

Pandemic unadjuvanted influenza A (H1N1) vaccine in dermatomyositis and polymyositis: Immunogenicity independent of therapy and no harmful effect in disease

The goal of the present study was to evaluate the influence of the influenza A H1N1/2009 vaccine on dermatomyositis/polymyositis (DM/PM) disease parameters and the potential deleterious effect of therapy on immune response. Thirty-seven DM and 21 PM patients (Bohan and Peter's criteria) were gender- and age-matched to 116 healthy controls. Seroprotection, seroconversion, the geometric mean titers (GMTs) and the factor increase (FI) in the GMTs were calculated. Disease safety was determined from a muscle enzyme analysis and the DM/PM scores [patient's visual analog scale (VAS), physician's VAS, manual muscle strength (MMT-8)] evaluated pre- and post-vaccination. The mean age (43.1 +/- 9.9 vs. 43.8 +/- 8.4 years, p = 0.607) and gender distribution (p = 1.00) were comparable between the patients and controls. After 21 days, seroconversion (p = 0.394), seroprotection (p = 0.08), GMT (p = 0.573) and the FI in the GMT (p = 0.496) were similar in both groups. The disease and muscle parameters remained stable throughout the study, including the creatine kinase (p = 0.20) and aldolase levels (p = 0.98), the physicians' VAS (p = 1.00), the patients' VAS (p = 1.00) and the MMT-8 (p = 1.00). Regarding the influence of treatment, the seroconversion rates were comparable between the controls and patients undergoing treatment with glucocorticoid (GC) (p = 0.969), GC >0.5 mg/kg/day (p = 0.395) and GC + immunosuppressors (p = 0.285). Vaccine-related adverse events were mild and similar in the DM/PM and control groups (p > 0.05). Our data support the administration of the pandemic influenza A H1N1/2009 vaccination in DM/PM, as we found no short-term harmful effects related to the disease itself and adequate immunogenicity in spite of therapy. Further studies are necessary to identify any long-term adverse effects in patients with these diseases.(c) 2012 Elsevier Ltd. All rights reserved.

TNF blockers show distinct patterns of immune response to the pandemic influenza A H1N1 vaccine in inflammatory arthritis patients

Methods. One hundred and twenty patients (RA, n = 41; AS, n = 57; PsA, n = 22) on anti-TNF agents (monoclonal, n = 94; soluble receptor, n = 26) were compared with 116 inflammatory arthritis patients under DMARDs and 117 healthy controls. Seroprotection, seroconversion (SC), geometric mean titre, factor increase in geometric mean titre and adverse events were evaluated 21 days after vaccination. Results. After immunization, SC rates (58.2% vs 74.3%, P = 0.017) were significantly lower in SpA patients receiving anti-TNF therapy, whereas no difference was observed in RA patients receiving this therapy compared with healthy controls (P = 0.067). SpA patients receiving mAbs (infliximab/adalimumab) had a significantly lower SC rate compared with healthy controls (51.6% vs 74.3%, P = 0.002) or those on DMARDs (51.6% vs 74.7%, P = 0.005), whereas no difference was observed for patients on etanercept (86.7% vs 74.3%, P = 0.091). Further analysis of non-seroconverting and seroconverting SpA patients revealed that the former group had a higher mean age (P = 0.003), a higher frequency of anti-TNF (P = 0.031) and mAbs (P = 0.001) and a lower frequency of MTX (P = 0.028). In multivariate logistic regression, only older age (P = 0.015) and mAb treatment (P = 0.023) remained significant factors for non-SC in SpA patients. Conclusion. This study revealed a distinct disease pattern of immune response to the pandemic influenza vaccine in inflammatory arthritis patients receiving anti-TNF agents, illustrated by a reduced immunogenicity solely in SpA patients using mAbs. Trial Registration: ClinicalTrials.gov, ext-link-type="uri" xlink:href="www.clinicaltrials.gov" xmlns:xlink="http://www.w3.org/1999/xlink">www.clinicaltrials.gov, NCT01151644.

Frequency of subtype B and F1 dual infection in HIV-1 positive, Brazilian men who have sex with men

Background: Because various HIV vaccination studies are in progress, it is important to understand how often inter- and intra-subtype co/superinfection occurs in different HIV-infected high-risk groups. This knowledge would aid in the development of future prevention programs. In this cross-sectional study, we report the frequency of subtype B and F1 co-infection in a clinical group of 41 recently HIV-1 infected men who have sex with men (MSM) in Sao Paulo, Brazil. Methodology: Proviral HIV-1 DNA was isolated from subject's peripheral blood polymorphonuclear leukocytes that were obtained at the time of enrollment. Each subject was known to be infected with a subtype B virus as determined in a previous study. A small fragment of the integrase gene (nucleotide 4255-4478 of HXB2) was amplified by nested polymerase chain reaction (PCR) using subclade F1 specific primers. The PCR results were further confirmed by phylogenetic analysis. Viral load (VL) data were extrapolated from the medical records of each patient. Results: For the 41 samples from MSM who were recently infected with subtype B virus, it was possible to detect subclade F1 proviral DNA in five patients, which represents a co-infection rate of 12.2%. In subjects with dual infection, the median VL was 5.3 x 10(4) copies/ML, whereas in MSM that were infected with only subtype B virus the median VL was 3.8 x 10(4) copies/ML (p > 0.8). Conclusions: This study indicated that subtype B and F1 co-infection occurs frequently within the HIV-positive MSM population as suggested by large number of BF1 recombinant viruses reported in Brazil. This finding will help us track the epidemic and provide support for the development of immunization strategies against the HIV.

First evidence of the emergence of novel putative infectious bronchitis virus genotypes in Cuba

The emergence of new infectious bronchitis virus (IBV) genotypes or serotypes along with the poor cross-protection observed among IBV serotypes have complicated the avian infectious bronchitis (IB) control programs in different geographic regions. In Cuba, the lack of genetic information regarding IBV and the increasing epidemiological importance of this virus in Cuban chicken flocks demand further characterization of IBV isolates. In the present work, studies of genetic diversity and phylogenetic relationships among recent IBV isolates from Cuban chicken flocks showing respiratory disorders were performed. Two putative genotypes genetically different to the Massachusetts genotype H120 strain used in the Cuban vaccination program were found in the flocks assessed. In addition, a potential nephropathogenic IBV isolate was found by first time in Cuba. (C) 2012 Elsevier Ltd. All rights reserved.

MRKAd5 HIV-1 Gag/Pol/Nef Vaccine-Induced T-Cell Responses Inadequately Predict Distance of Breakthrough HIV-1 Sequences to the Vaccine or Viral Load

Background: The sieve analysis for the Step trial found evidence that breakthrough HIV-1 sequences for MRKAd5/HIV-1 Gag/Pol/Nef vaccine recipients were more divergent from the vaccine insert than placebo sequences in regions with predicted epitopes. We linked the viral sequence data with immune response and acute viral load data to explore mechanisms for and consequences of the observed sieve effect. Methods: Ninety-one male participants (37 placebo and 54 vaccine recipients) were included; viral sequences were obtained at the time of HIV-1 diagnosis. T-cell responses were measured 4 weeks post-second vaccination and at the first or second week post-diagnosis. Acute viral load was obtained at RNA-positive and antibody-negative visits. Findings: Vaccine recipients had a greater magnitude of post-infection CD8+ T cell response than placebo recipients (median 1.68% vs 1.18%; p = 0.04) and greater breadth of post-infection response (median 4.5 vs 2; p = 0.06). Viral sequences for vaccine recipients were marginally more divergent from the insert than placebo sequences in regions of Nef targeted by pre-infection immune responses (p = 0.04; Pol p = 0.13; Gag p = 0.89). Magnitude and breadth of pre-infection responses did not correlate with distance of the viral sequence to the insert (p. 0.50). Acute log viral load trended lower in vaccine versus placebo recipients (estimated mean 4.7 vs 5.1) but the difference was not significant (p = 0.27). Neither was acute viral load associated with distance of the viral sequence to the insert (p>0.30). Interpretation: Despite evidence of anamnestic responses, the sieve effect was not well explained by available measures of T-cell immunogenicity. Sequence divergence from the vaccine was not significantly associated with acute viral load. While point estimates suggested weak vaccine suppression of viral load, the result was not significant and more viral load data would be needed to detect suppression.

Vesicles as carriers of virulence factors in parasitic protozoan diseases

Different types of shed vesicles as, for example, exosomes, plasma-membrane-derived vesicles or microparticles, are the focus of intense research in view of their potential role in cell cell communication and under the perspective that they might be good tools for immunotherapy, vaccination or diagnostic purposes. This review discusses ways employed by pathogenic trypanosomatids to interact with the host by shedding vesicles that contain molecules important for the establishment of infection, as opposed to previous beliefs considering them as a waste of cellular metabolism. Trypanosomatids are compared with Apicomplexa, which circulate parasite antigens bound to vesicles shed by host cells. The knowledge of the origin and chemical composition of these different vesicles might lead to the understanding of the mechanisms that determine their biological function. (C) 2012 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Brazilian avian metapneumovirus subtypes A and B: experimental infection of broilers and evaluation of vaccine efficacy

Santos M.B., Martini M.C., Ferreira H.L., Silva L.H.A., Fellipe P.A., Spilki F.R. & Arns C.W. 2012. Brazilian avian metapneumovirus subtypes A and B: experimental infection of broilers and evaluation of vaccine efficacy. Pesquisa Veterinaria Brasileira 32(12):1257-1262. Laboratorio de Virologia, Instituto de Biologia, Universidade Estadual de Campinas, Rua Monteiro Lobato s/n, Cx. Postal 6109, Campinas, SP 13083-970, Brazil. E-mail: arns@unicamp.br Avian metapneumovirus (aMPV) is a respiratory pathogen associated with the swollen head syndrome (SHS) in chickens. In Brazil, live aMPV vaccines are currently used, but subtypes A and, mainly subtype B (aMPV/A and aMPV/B) are still circulating. This study was conducted to characterize two Brazilian aMPV isolates (A and B subtypes) of chicken origin. A challenge trial to explore the replication ability of the Brazilian subtypes A and B in chickens was performed. Subsequently, virological protection provided from an aMPV/B vaccine against the same isolates was analyzed. Upon challenge experiment, it was shown by virus isolation and real time PCR that aMPV/B could be detected longer and in higher amounts than aMPV/A. For the protection study, 18 one-day-old chicks were vaccinated and challenged at 21 days of age. Using virus isolation and real time PCR, no aMPV/A was detected in the vaccinated chickens, whereas one vaccinated chicken challenged with the aMPV/B isolate was positive. The results showed that aMPV/B vaccine provided a complete heterologous virological protection, although homologous protection was not complete in one chicken. Although only one aMPV/B positive chicken was detected after homologous vaccination, replication in vaccinated animals might allow the emergence of escape mutants.

Immune response and tolerability of varicella vaccine in children and adolescents with systemic lupus erythematosus previously exposed to varicella-zoster virus

Objectives The aim of the present paper is to evaluate the immune response and tolerability of varicella vaccine in children and adolescents with systemic lupus erythematosus previously exposed to varicella-zoster virus. Methods We performed a prospective and controlled study on a group of 54 SLE patients that were chosen at random to be or not to be vaccinated (28 were vaccinated and 26 were not). Twenty-eight healthy controls, of matching age and sex were also vaccinated. All were submitted to a questionnaire, physical evaluation and laboratory assays: lymphocyte immuno-phenotyping by flow cytometry, plasma varicella zoster virus (VZV) serology by ELISA and in vitro interferon gamma (IFN gamma) production by T-cells after stimulus with VZV antigen. They were evaluated before vaccination and at 30, 45, 180 and 360 days afterwards. Results We did not observe any differences in the frequency of adverse events in both vaccinated groups. At study entry, all individuals were seropositive for VZV antibodies. The serum VZV antibody titres similarly increased after vaccination. The frequency of flares and the SLEDAI score were also similar among the patients. Thirty days after vaccination the production of IFN gamma specific to VZV was lower in the SLE group compared to healthy, controls. In the follow-up we observed 4 cases of herpes zoster in the SLE unvaccinated group, but no zoster in the vaccinated group. Conclusion The varicella vaccine was well tolerated in SLE group, who had pre-existing immunity to varicella. The varicella vaccine immunogenicity measurement by serum antibody titres was appropriate. The incidence of HZ was lower in the vaccinated lupus group.

Bacillus atrophaeus inactivated spores as a potential adjuvant for veterinary rabies vaccine

Rabies is a viral encephalitis, nearly always fatal, but preventable through vaccines. Rabid animal bite is the prime transmission act, while veterinary vaccination is one of the best strategies for rabies general prevention. Aluminum compounds and saponin are the commercial adjuvants used for this vaccine nowadays. Nevertheless, aluminum compounds can provoke undesired side effects and saponin has a narrow activity range without toxicity. B. atrophaeus inactivated spores (BAIS), with or without saponin, were then used as an alternative to boost the inactivated rabies virus response. BAIS was as effective as saponin in augmenting antibody titers, but combination of both adjuvants doubled the titers raised by them individually. The combined adjuvant formulation maintained viability for 21 months when stored at 4-8 degrees C. Overall, BAIS was demonstrated as a viable alternative to commercial adjuvants, while its combination with saponin resulted in even higher vaccine potency with good stability. (C) 2012 Elsevier Ltd. All rights reserved.