Cross-sectional study on Brucella spp., Leptospira spp. and Salmonella spp. in bats from Montes Claros,Minas Gerais,Brazil

The understanding on the role of bats in the ecology of zoonotic diseases, especially its relevance as a carrier of pathogens, is important for the determination of preventive measures considering the One Health context. The present study aimed to investigate the presence of Brucella spp., Leptospira spp. and Salmonella spp. in blood (n = 163), liver (n = 35) and spleen (n = 62) samples from bats captured in Montes Claros, Minas Gerais, Brazil. Only Salmonella spp. was found in a blood sample of an insectivorous female bat of the species Lasiurus blossevilli, evidencing the capacity of this animal species to host this pathogen. In conclusion, our results in bats from Montes Claros indicate that they do not act as hosts for Brucella spp. and Leptospira spp., although being potential carriers of Salmonella spp. in a low prevalence.     

Putative human and avian risk factors for avian influenza virus infections in backyard poultry in Egypt

Highly pathogenic influenza A virus subtype H5N1 causes significant poultry mortality in the six countries where it is endemic and can also infect humans. Egypt has reported the third highest number of poultry outbreaks (n = 1084) globally. The objective of this cross-sectional study was to identify putative risk factors for H5N1 infections in backyard poultry in 16 villages in Damietta, El Gharbia, Fayoum, and Menofia governorates from 2010–2012. Cloacal and tracheal swabs and serum samples from domestic (n = 1242) and wild birds (n = 807) were tested for H5N1 via RT-PCR and hemagglutination inhibition, respectively. We measured poultry rearing practices with questionnaires (n = 306 households) and contact rates among domestic and wild bird species with scan sampling. Domestic birds (chickens, ducks, and geese, n = 51) in three governorates tested positive for H5N1 by PCR or serology. A regression model identified a significant correlation between H5N1 in poultry and the practice of disposing of dead poultry and poultry feces in the garbage (F = 15.7, p < 0.0001). In addition, contact between domestic and wild birds was more frequent in villages where we detected H5N1 in backyard flocks (F = 29.5, p < 0.0001).     

Prevalence and risk factors for Salmonella spp. and Campylobacter spp. caecal colonization in broiler chicken and turkey flocks slaughtered in Quebec, Canada

We conducted an observational study to estimate prevalence and risk factors for Salmonella spp. and Campylobacter spp. caecal colonization in poultry. Eighty-one broiler chicken and 59 turkey flocks selected among flocks slaughtered in the province of Quebec, Canada, were included in the study. Flock status was evaluated by culturing pooled caecal contents from about 30 birds per flock. Exposure to potential risk factors was evaluated with a questionnaire. Odds ratios were computed using multivariable logistic regression.

The prevalence of Salmonella-positive flocks was 50% (95% CI: 37, 64) for chickens and 54% (95% CI: 39, 70) for turkeys, respectively. Odds of Salmonella colonization were 2.6 times greater for chicken flocks which failed to lock the chicken house permanently. In turkeys, odds of Salmonella colonization were 4.8–7.7 times greater for flocks which failed to be raised by ≤2 producers with no other visitors allowed onto the premises, or origin from a hatchery.

The prevalence of Campylobacter-positive flocks was 35% (95% CI: 22, 49) for chickens and 46% (95% CI: 30, 62) for turkeys. Odds of colonization were 4.1 times higher for chicken flocks raised on farms with professional rodent control and 5.2 times higher for flocks with manure heap >200 m from the poultry house, and also increased with the number of birds raised per year on the farm and with the age at slaughter. For turkeys, odds of Campylobacter flock colonization were 3.2 times greater in flocks having a manure heap at ≤200 m from poultry house and 4.2 times greater in flocks drinking unchlorinated water.     

Quantification of water as a potential risk factor for cross-contamination with Salmonella,Campylobacter and Listeria in a poultry abattoir

1. Water used in a modern poultry processing line was tested from October 2005 to June 2006 to determine the level of bacteria in an abattoir in Germany.

2. A total of 420 water samples were taken from 14 processing sites (PSs), at 10 times, and from three different hours of the working shift at three sampling hours (SHs) at 5:00 a.m. (SH 1), 9:00 a.m. (SH 2) and 12:00 a.m. (SH 3). Each sample was assessed for the aerobic plate count (APC) and the prevalence of Salmonella, Campylobacter, Listeria and Yersinia over 30 sampling weeks. The APC numbers of each PS from three SHs were compared, and the prevalence of Salmonella, Campylobacter, Listeria and Yersinia from each PS of three SHs was determined as well as change from the initial PS to the end of the processing line.

3. A total of 46 water samples were positive for Salmonella, 120 positive for Campylobacter and 4 positive for Listeria. None of the water samples was found to be positive for Yersinia. During the course of the day, the APC increased. Salmonella was mostly found during SH 1 (5 a.m.) in water from all PSs. A high number of Campylobacter were observed at SH 2 (9 a.m.) and SH 3 (12 a.m.) from all PSs.

4. The results show that water, which is still used in substantial amounts in present poultry processing technology, can serve as a carrier for Salmonella and Campylobacter.

5. The findings indicate that birds might progressively contaminate the equipment and become contaminated via the same equipment, that water at every processing position of the line constitutes a risk and that more attention should be paid to effective water management in the processing plan.     

链球菌、金黄色葡萄球菌、沙门菌和大肠杆菌多重PCR检测方法的建立及应用

根据NCBI上已收录的链球菌ef-tu基因、金黄色葡萄球菌nuc基因、沙门菌hut基因和大肠杆菌23SrRNA基因的序列,设计并合成4对特异性引物,通过优化多重PCR的反应条件,建立了能够同时检测4种细菌混合感染的多重PCR诊断方法。特异性分析结果表明,应用该方法可以从链球菌、金黄色葡萄球菌、沙门菌和大肠杆菌以及4种细菌的混合物中扩增出4条大小分别为197、278、495和652bp的特异性条带,其他对照组的检测结果均为阴性;敏感性分析表明,该方法对4种病原菌基因组DNA的检出量分别为链球菌25.6pg、金黄色葡萄球菌33.2pg、沙门菌35.7pg、大肠杆菌52.1pg;人工模拟感染样本检测表明,该方法能从混合感染的病料中特异地检测出4种病原菌。本试验建立的多重PCR方法具有特异性强,敏感度高,稳定性好的特点,可以有效的检测链球菌、金黄色葡萄球菌、沙门菌和大肠杆菌的混合感染。     

Quantitative real-time PCR assays for the concurrent diagnosis of infectious laryngotracheitis virus,Newcastle disease virus and avian metapneumovirus in poultry

Newcastle disease (ND), infectious laryngotracheitis (ILT) and avian metapneumovirus (aMPV) can be similar making it critical to quickly differentiate them. Herein, we adapted pre-existing molecular-based diagnostic assays for NDV and ILTV, and developed new assays for aMPV A and B, for use under synchronized thermocycling conditions. All assays performed equivalently with linearity over a 5 log₁₀ dynamic range, a reproducible (R² > 0.99) limit of detection of ≥ 10 target copies, and amplification efficiencies between 86.8%–98.2%. Using biological specimens for NDV and ILTV showed 100% specificity. Identical amplification conditions will simplify procedures for detection in diagnostic laboratories.     

Apparent seroprevalence,isolation and identification of risk factors for brucellosis among dairy cattle in Goa,India

Brucellosis is a highly contagious zoonotic infection affecting livestock and human beings. The disease has been reported worldwide except in few countries where it has been eradicated. The prevalence of brucellosis among cattle from 11 farms having a history of abortions was studied. A total of 481 samples comprising of blood, milk, vaginal swabs, vaginal discharges, placental tissues and fetal tissues were collected from 296 animals. Clinical samples were processed for the isolation of Brucella. Serum samples (n = 296) were tested by Rose Bengal Plate Test (RBPT) and indirect ELISA. A total of 90 (30.40%) and 123 (41.55%) samples were positive by RBPT and indirect ELISA, respectively. Also 27.02% samples were positive by both the tests. Brucella isolates (n = 8) were recovered from clinical samples using Brucella selective media. All the isolates demonstrated PCR amplification for the bcsp31 and IS711 genes. Amplification of Brucella abortus specific primer was demonstrated by all the isolates in AMOS PCR indicating isolates to be of either B. abortus biotype 1, 2 or 4. Risk factors for transmission of brucellosis among cattle population were studied by field surveys. It was observed that lack of awareness about brucellosis (OR = 8.739, P = 0.138) and inadequate floor space (OR = 0.278, P = 0.128) were crucial risk factors for transmission of bovine brucellosis.