1,721,006 research outputs found
Epidemiologic and Economic Analyses on Highly Pathogenic Avian Influenza H5N1 in Nigeria and Egypt
No full textInfluenza A viruses have caused several devastating outbreaks in poultry with some zoonotic infections and deaths in humans. To control the viruses and their continuous circulation in poultry population, an understanding of the epidemiology of the viruses is needed. An evaluation of the situation of avian influenza A H5N1 in two African countries most affected by this virus was conducted. To that end, two aims were pursued: (i) to identify the factors that played important roles in the dissemination and circulation of the virus, and (ii) to explore the potentials of the virus from becoming endemic in the poultry populations in Africa. The analyses partly described the extent of H5N1outbreaks in Nigeria in at-risk and non-infected premises and live bird markets in the country. All samples (tracheal and cloacal swabs, parenchymatous tissues and sera) were analysed using virus isolation, reverse-transcription polymerase chain reaction and serology. Primary data on influenza A H5N1 in human as recorded by the Egyptian government was collected and analysed using different variables and risk factors for HPAI H5N1 virus infection in poultry farms in Nigeria during 2006-2007 outbreaks in Nigeria were explored using the conditional logistic regression models. Factors that supported infections in new premises included: receiving visitors on farm premises, purchase of live poultry/products, farm workers that live outside the premises. Because biosecurity is important to reduce risks of infection in poultry farms, the effects and costs associated with the implementation or neglect of biosecurity, as well as the feasibility of implementation in the household poultry in Egypt were evaluated. Risks of particular importance for the household poultry were categorised into people-related, environmental-related and other birds/animal-related risks. Biosecurity measures were compatible in the household poultry and it is 8.45 times better to implement biosecurity than to do nothing against HPAI H5N1. The financial risk analysis was robust and withstood sensitivity analysis. The change that may occur in the course of the household poultry project was accommodated profitably. The effect of road network and its contributions to the epidemics in Nigeria were evaluated to determine whether HPAI H5N1 exhibit properties of network theory. Spatial aggregation of cases (disease clusters), links among similar ‘nodes’ (assortativity), simultaneous activation of similar nodes (synchronicity), epidemic flows moving from highly to poorly connected nodes (directionality), and a Pareto analyses pattern were observed including synchronicity and directionality of spread properties. An exploratory analysis was conducted on the probability of human infection through the oral contacts with A-H5N1 contaminated meat. Detailed quantitative risk assessment using predictive microbiology-process risk model revealed that up to 15,159 humans may have contracted HPAI H5N1 in Africa, with 1,964 deaths. These figures are higher than those officially reported. The model has limitations but bias associated with official epidemiological statistics which are often prone to underreporting, lack of awareness especially in the rural communities and censoring effects may also account for this discrepancy. Finally, continuous monitoring of influenza viruses in Africa and implementation of measures that should reduce the burden of infection in Africa is necessary
First confirmed case of bovine besnoitiosis in an imported bull in Belgium
Get PDFBesnoitia besnoiti is a protozoan parasite known to cause important economic losses in the cattle industry in Africa, Asia and the Mediterranean area. In the last years, (re-) emergence of the parasite has been reported in France, Germany, Hungary and Italy with in some cases, establishment of an endemic infection. In this article, the first case of besnoitiosis in Belgium in a Blonde d'Aquitaine bull imported from the south of France is described. Additionally, a brief overview of the epidemiology of the disease is provided
High aerial ammonia as cause for increased rate of return to oestrus in sows: a case report
No full textIntroduction Non-infectious causes of reproductive failure are most often detected when farms report an increased rate of return to oestrus (RTO) with a regular interval between inseminations. However, non-infectious causes can result in RTO with an irregular interval between inseminations due to early embryonic death (EED) because of chronic physical stress. Methods This case report considers the data analysis, farm inspection and evaluation of feed, feeding, behaviour, climate and housing with regard to a farm of 500 sows experiencing an increased rate of return to oestrus. Results Data analysis an increased rate of RTO (average 11%) in sows of all parity. In addition an increased rate of too small litters was found. Finally, in 2nd cycle sows, a classical second litter syndrome was observed . The data, nor the anamnesis revealed any increased rates of abortions, mummies, decreased gestation length or diseased sows thereby excluding infectious causes of RTO and thereby suggesting EED. An evaluation of stressors for gestating sows was needed to detect the cause of EED. A thorough evaluation of feed and feeding (in electronic sow feeding stations), as well as human-sow interaction did not reveal any abnormalities. However, video behaviour analysis revealed that -75% of gestating sows rest in a sternal position, when instead lying in flank position is considered to be normal. Analysis of the climate analysis revealed a slightly increased ambient temperature (25ć) as well as an elevated aerial ammonia concentration (75 - 112 ppm) due to the fact that incoming air fell into the manure pit. Analysis of the manure pit construction and housing revealed an improper design to fit housing of gestating sows. Conclusion As no other cause of EED was found it was concluded that the high aerial ammonia is the likely cause of EED on this farm. Advice is currently being implemented to reduce ambient temperature and pit ventilation. However, improper housing design restricts this farmer to implement a scientific based and sustainable solution. This case shows that combining extensive data analysis and a thorough evaluation of stressors enables the identification of causes of EED on farms
Simulation study of the mechanisms underlying outbreaks of clinical disease caused by Actinobacillus pleuropneumoniae in finishing pigs
No full textActinobacillus pleuropneumoniae is a major cause of respiratory disease in pigs. Many farms are endemically infected without apparent disease, but occasionally severe outbreaks of pleuropneumonia occur. To prevent and control these outbreaks without antibiotics, the underlying mechanisms of these outbreaks need to be understood. Outbreaks are probably initiated by a trigger (common risk factor) changing the host-pathogen interaction, but it is unclear whether this trigger causes all cases directly (trigger mechanism), or whether the first case starts a transmission chain inducing disease in the infected contacts (transmission mechanism). The aim of this study was to identify conditions under which these mechanisms could cause A. pleuropneumoniae outbreaks, and to assess means for prevention and control. Outbreaks were first characterised by data from a literature review, defining an average outbreak at 12 weeks of age, affecting 50% of animals within 4 days. Simple mathematical models describing the two mechanisms can reproduce average outbreaks, with two observations supporting the trigger mechanism: (1) disease should be transmitted 50 times faster than supported by literature if there is a transmission chain; and (2) the trigger mechanism is consistent with the absence of reported outbreaks in young pigs as they have not yet been colonised by the bacterium. In conclusion, outbreaks of A. pleuropneumoniae on endemic farms are most likely caused by a trigger inducing pneumonia in already infected pigs, but more evidence is needed to identify optimum preventive interventions
Chlamydia psittaci and C. avium in feral pigeon (Columba livia domestica) droppings in two cities in the Netherlands
No full textBackground: Feral pigeons (Columba livia domestica) live and breed in many city centres and contact with their droppings can be a hazard for human health if the birds carry Chlamydia psittaci. Objective: The aim of this study was to establish whether pigeon droppings in two Dutch cities (Utrecht and Haarlem) contain C. psittaci and/or C. avium, which could be a potential hazard for transmission to humans. Methods: In May 2017 seven feral pigeon ‘hot spots’ with between 5 and 40+ pigeons present were identified in two cities by visual observations over two days. During the following ten days fresh droppings were collected at these hot spots and the samples were pooled per three droppings to achieve 40–41 samples per city. Samples were analysed for Chlamydia DNA with a broad range 23S Chlamydiaceae Real-Time PCR and positive samples were tested with a specific C. psittaci and C. avium Real-Time PCR. Positive C. psittaci samples were genotyped. Results: C. psittaci and C. avium were detected in both cities. For C. psittaci the prevalences in Utrecht and Haarlem were 2.4% and 7.5%, respectively; for C. avium 36.6% and 20.0%, respectively. One sample contained both species. All C. psittaci samples belonged to genotype B. Conclusion: C. psittaci and C. avium are present in feral pigeon droppings in Utrecht and Haarlem. Human contact with droppings from infected pigeons or inhalation of dust from dried droppings represent a potential hazard to public health
Protein and fat mobilization and associations with serum beta-hydroxybutyrate concentrations in dairy cows
No full textThe objective of this study was to obtain information on variation between dairy cows in muscle and fat tissue mobilization around parturition and to study the association between protein and fat mobilization and serum beta-hydroxybutyrate (BHBA) concentrations (hyperketonemia) in this period. Thirty-four cows kept under similar conditions at a university dairy farm (no experimental treatments) were monitored from 4 wk before until 8 wk after calving. Mobilization of muscle protein was investigated by analysis of plasma 3-methylhistidine concentrations (3-MH, analyzed by a recently developed HPLC tandem mass spectrometry method) and ultrasound measurements of longissimus muscle thickness. Mobilization of fat tissue was monitored by serum nonesterified fatty acid (NEFA) concentrations and ultrasound measurements of backfat thickness. Large variation was observed between cows in onset and duration of periparturient protein and fat mobilization. Plasma 3-MH concentrations and muscle thickness profiles indicated that protein mobilization started, on average, before parturition and continued until approximately wk 4 of lactation. Serum NEFA concentrations and backfat thickness profiles showed that fat mobilization occurred from parturition until the end of the study. Thus, muscle protein mobilization occurred in advance of fat mobilization in most cows from this study. We hypothesized that this might be due to a prepartum amino acid deficiency in the absence of negative energy balance. The incidence of hyperketonemia in this study was 16/34 = 47%. With the exception of 3 cows defined as having severe hyperketonemia, cows with lower 3-MH concentrations had higher serum BHBA concentrations. A possible explanation for this observation might be that higher mobilization of protein around calving might restrict ketone body production due to the higher availability of glucogenic precursors in the period of most severe negative energy balance and highest fat mobilization. The validity of this hypothesis needs to be confirmed, but data from this study indicate that further research on the role of protein mobilization in the etiology of hyperketonemia in dairy cows is needed
Erratum to: Monitoring cow comfort and rumen health indices in a cubicle-housed herd with an automatic milking system: a repeated measures approach
Get PDF[This corrects the article DOI: 10.1186/s13620-015-0040-7.]
Effect of simultaneous exposure of pigs to Streptococcus suis serotypes 2 and 9 on colonization and transmission of these serotypes, and on mortality
No full textIntroduction Streptococcus suis (S. suis) is a major pathogen in pigs worldwide, causing meningitis, septicemia, arthritis, endocarditis, and mortality. S. suis in humans is considered as an emerging life-threatening infection, especially in Asia. Main risk factor for human infection is direct contact with infected pigs or their products.In pigs, various serotypes of S. suis have been identified as cause of clinical infection. Comparable to e.g. Streptococcus pneumoniae in human, the presence of S. suis serotypes in pigs, however, differs between geographical areas, and varies over time. In several European countries, including The Netherlands, there has been a shift in predominant serotype from serotype 2 towards serotype 9 in the last two decades.We hypothesize a relation with one serotype affecting the other in colonization, transmission and invasion. The aim of this study was to evaluate whether simultaneous exposure of pigs to serotypes 2 and 9 affects the colonization and transmission of each serotype, and affects mortality. Methods Thirty-six caesarean-derived/colostrum-deprived piglets were randomly assigned to three groups, and there housed pair-wise. At 6 weeks-of-age one pig per pair was inoculated intranasally with either one (serotype 2 or 9; ‘mono-group’) or two serotypes simultaneously (‘dual-group’). Pigs in the mono-groups received 1x109 CFU serotype 2 or 9, and in the dual-group a mixture of 1x109 CFU serotype 2 and 1x109 CFU serotype 9 (i.e. 2x109 CFU S. suis/pig). The other pig of each pair was contact-exposed. Tonsillar brushing samples were collected from all pigs during three weeks post inoculation. Bacterial loads in the samples were quantified using multiplex real-time PCR. Transmission rates of the serotypes among pigs were estimated using a mathematical SI-model. Results The transmission rates for serotype 9 were 67/day (95%CI: 0-∞) and 4.1/day (95%CI: 1.6-10.6), for the mono- and dual-group, respectively (P=0.99). The transmission rates for serotype 2 were estimated at 29.4/day (95%CI: 0-∞) in the mono-group, and 2.9/day (95%CI: 1.2-6.9) in the dual-group (P=0.99). Bacterial loads did not differ significantly between serotypes (P=0.99). In the dual-group the average serotype 2 load in tonsillar samples from contact pigs was 1.4-1.8 10LogCFU/sample (i.e. 25-40 fold) reduced on days 1 to 4 and 6, in comparison to the mono-group (P<0.01).Simultaneous exposure to the serotypes reduced the mortality hazard 6.3 times (95%CI: 2.0-19.8) compared to exposure to serotype 2 only, and increased it 6.6 times (95%CI: 1.4–30.9) compared to exposure to serotype 9 only. Conclusions Transmission rates for serotype 2 did neither differ significantly between serotypes, nor for a single serotype between the mono- and dual-group. This implies that simultaneous exposure to serotypes 2 and 9 does not affect the relative transmission rates of each serotype.Natural contact exposure to serotypes 2 and 9 simultaneously affects the clinical outcome of an infection of a particular serotype in a population, possibly by affecting the mucosal load. This might have contributed to the observed shift in distribution of clinical isolates in the field from serotype 2 to 9
Effects of beta-hydroxybutyrate and isoproterenol on lipolysis in isolated adipocytes from periparturient dairy cows and cows with clinical ketosis
No full textAn in vitro model was used to investigate effects of beta-hydroxybutyrate and isoproterenol (beta-adrenergic receptor agonist) on lipolysis in isolated adipocytes from late pregnant and recently calved dairy cows (n = 5) and cows with clinical ketosis (n =3). Incubation with 3.0 mmol/L beta-hydroxybutyrate reduced lipolysis in isolated adipocytes. This inhibitory effect was lower in the first lactation week (47% +/- 16%) compared with late pregnancy (71% +/- 6.5%). Incubation with 0.3 mu mol/L isoproterenol stimulated lipolysis in isolated adipocytes from periparturient dairy cows. Basal lipolysis resulted in non-esterified fatty acid to glycerol ratios in the incubation media of 2.0 +/- 0.23 in prepartum samples, 2.1 +/- 0.23 in the first lactation week and 2.2 +/- 0.09 in cows with clinical ketosis. beta-Hydroxybutyrate reduced lipolysis by 45% +/- 9.6% in isolated adipocytes from cows with clinical ketosis, indicating that impaired feedback of beta-hydroxybutyrate may not play a role in the disease etiology. (C) 2012 Elsevier Ltd. All rights reserved
Pressure mat analysis of naturally occurring lameness in young pigs after weaning
Get PDFBACKGROUND: Lameness is a common problem in modern swine husbandry. It causes welfare problems in affected pigs as well as financial problems for farmers. To minimize these negative consequences of lameness, new treatment and prevention strategies need to be developed and validated using objective and quantitative measurement techniques. An example of such a putative diagnostic tool is the use of a pressure mat. Pressure mats are able to provide both objective loading (kinetic) as well as objective movement (kinematic) information on pig locomotion.In this study, pressure mat analysis was used to assess compensatory force redistribution in lame pigs; in particular a predefined set of four pressure mat parameters was evaluated for its use to objectively distinguish clinically lame from sound pigs. Kinetic data from 10 clinically lame and 10 healthy weaned piglets were collected. These data were analyzed to answer three research questions. Firstly the pattern of compensatory weight distribution in lame animals was studied using the asymmetry indices (ASI) for several combinations of limbs. Secondly, the correlation between total left-right asymmetry index and visual scores of lameness was assessed. Thirdly, by using receiver-operated curve (ROC) analysis, optimal cutoff values for these ASIs were then calculated to objectively detect lame pigs. RESULTS: Lame animals generally showed a shift in loading towards their diagonal and contralateral limbs, resulting in a clear left-right asymmetry. The degree of lameness as graded by visual scoring correlated well with the total left-right ASIs. Lame pigs could be objectively distinguished from sound pigs based on clear cutoff points calculated by ROC analysis for the complete set of four evaluated parameters. CONCLUSIONS: The gait of lame pigs is asymmetric, due to the unloading of the affected limb and concomitant weight redistribution towards other limbs. This asymmetry objectively expressed as total left-right asymmetry, correlates well with the subjective visual lameness scoring and can be used to objectively distinguish lame from sound pigs. Pressure mat gait analysis of pigs, therefore, appears to be a promising and useful tool to objectively quantify and possibly early detect lameness in pigs
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