Temporal Aspects of Foot-Pad Dermatitis in Swedish Broilers

This study aimed at analysing the temporal aspects of foot-pad dermatitis in Swedish broilers. The information on disease prevalence and severity was based on a 2-year foot-health surveillance programme where information on producer, breed, feed manufacturer, region, abattoir, date of slaughter and several other variables was recorded. The seasonal effects were evaluated using classical multiplicative decomposition time series analysis. This study shows that there has been a significantly consistent decrease in the prevalence of severe foot-pad lesions during the first 2 years of the programme. Looking at the development over time we found a trend-cycle component of 10.4% and a seasonal component of 48.7% resulting in a total adjusted R-square value of 58.5% for the total foot-pad score. This means that almost 60% of the variation in flock foot-pad score can be explained by the variable 'time', and that this variation was mainly related to seasonal effects but also to a general decreasing trend over the study period. However, substantial differences in temporal patterns among slaughterhouses, feed suppliers and regions were found. The time series analysis approach was found to be useful for this type of investigation when evaluating the effects of an intervention programme, and it can also be applied for projecting the future development of disease status in a stable population.     

Rearing Conditions and Foot-Pad Dermatitis in Swedish Turkey Poults

A method previously developed for classification of broiler foot health status was used in order to estimate the prevalence of foot-pad dermatitis in Swedish turkey poults. Data on foot health were collected from 53 commercial turkey flocks at slaughter. The producers were asked to fill in a questionnaire on rearing conditions and equipment for every flock. Lesions were very commonly observed, only 2% of the feet were classified as being without lesions, 78% had mild lesions (discoloration, erosions), and 20% had severe lesions (ulcers). There was a significant (p<0.01) effect of litter material on the presence of severe foot-pad dermatitis, flocks reared on straw showing higher prevalence than flocks reared on wood shavings. There was also a significant (p<0.001) effect of the type of water system, severe foot-pad dermatitis being more common in flocks reared in houses equipped with bell drinkers compared with flocks reared with small cups. The addition of extra litter during the rearing period resulted in significantly (p<0.01) lower prevalence of lesions compared with flocks where no extra litter had been added.     

Using Conjoint Analysis to Weight Broiler Welfare Variables Based on Slaughterhouse Data

The Council of the European Union adopted the welfare directive for broiler chickens in 2007 (Commission of the European Communities, 2007). The directive defines minimum demands and objectives for broiler production ranging from stocking density to welfare. This study found that the level of nonhuman animal welfare can be determined, for example, with welfare indexes that have different weight values for welfare variables. A total of 20 poultry experts from slaughterhouses, the feed industry, administration, and research received simulated data on 24 flocks. This included data for 5 welfare variables based on postmortem meat inspection information on commercial flocks and based on literature: mortality during rearing, foot-pad score, and the incidence of ascites, dermatitis, and cachexia in routine meat inspection. The experts ranked these flocks from the worst to the best according to animal welfare. Conjoint analysis weighted the relative importance of the welfare variables for broiler welfare. The study based relative importance for broiler welfare on 20 expert opinions: 24.6% for mortality, 35.9% for foot-pad score, 19.7% for the incidence of ascites, 15.7% for the incidence of dermatitis, and 4.1% for the incidence of cachexia. In the future, an index for broiler welfare evaluation could be developed based on the results of this study.     

Using conjoint analysis to weight broiler welfare variables based on slaughterhouse data

The Council of the European Union adopted the welfare directive for broiler chickens in 2007 (Commission of the European Communities, 2007). The directive defines minimum demands and objectives for broiler production ranging from stocking density to welfare. This study found that the level of nonhuman animal welfare can be determined, for example, with welfare indexes that have different weight values for welfare variables. A total of 20 poultry experts from slaughterhouses, the feed industry, administration, and research received simulated data on 24 flocks. This included data for 5 welfare variables based on postmortem meat inspection information on commercial flocks and based on literature: mortality during rearing, foot-pad score, and the incidence of ascites, dermatitis, and cachexia in routine meat inspection. The experts ranked these flocks from the worst to the best according to animal welfare. Conjoint analysis weighted the relative importance of the welfare variables for broiler welfare. The study based relative importance for broiler welfare on 20 expert opinions: 24.6% for mortality, 35.9% for foot-pad score, 19.7% for the incidence of ascites, 15.7% for the incidence of dermatitis, and 4.1% for the incidence of cachexia. In the future, an index for broiler welfare evaluation could be developed based on the results of this study.     

Prevention of Parent to Child Transmission (PPTCT) Program Data in India: An Emerging Data Set for Appraising the HIV Epidemic

Background

Evidence based resource allocation and decentralized planning of an effective HIV/AIDS response requires reliable information on levels and trends of HIV at national and sub-national geographic levels. HIV sentinel surveillance data from antenatal clinics (HSS-ANC) has been an important data source to assess the HIV/AIDS epidemic in India, but has a number of limitations. We assess the value of Prevention of Parent to Child Transmission (PPTCT) programme data to appraise the HIV epidemic in India.

Methods/Findings

HIV data from PPTCT sites were compared to HSS-ANC and general population level surveys at various geographic levels in the states of Karnataka, Maharashtra and Andhra Pradesh. Chi-square tests were used to ascertain statistical significance. PPTCT HIV prevalence was significantly lower than HSS-ANC HIV prevalence (0.92% vs. 1.22% in Andhra Pradesh, 0.65% vs. 0.89% in Karnataka, 0.52% vs. 0.60% in Maharashtra, p<0.001 for all three states). In all three states, HIV prevalence from PPTCT centres that were part of the sentinel surveillance was comparable to HSS-ANC prevalence but significantly higher than PPTCT centres that were not part of the sentinel surveillance. HIV prevalence from PPTCT data was comparable to that from general population surveys. In all three states, significant declines in HIV prevalence between 2007 and 2010 were observed with the PPTCT data set. District level analyses of HIV trends and sub-district level analysis of HIV prevalence were possible using the PPTCT and not the HSS-ANC data sets.

Conclusion

HIV prevalence from PPTCT may be a better proxy for general population prevalence than HSS-ANC. PPTCT data allow for analysis of HIV prevalence and trends at smaller geographic units, which is important for decentralized planning of HIV/AIDS programming. With further improvements to the system, India could replace its HSS-ANC with PPTCT programme data for surveillance.     

The prevalence of atypical scrapie in sheep from positive flocks is not higher than in the general sheep population in 11 European countries

Background

During the last decade, active surveillance for transmissible spongiform encephalopathies in small ruminants has been intensive in Europe. In many countries this has led to the detection of cases of atypical scrapie which, unlike classical scrapie, might not be contagious. EU legislation requires, that following detection of a scrapie case, control measures including further testing take place in affected flocks, including the culling of genotype susceptible to classical scrapie. This might result in the detection of additional cases. The aim of this study was to investigate the occurrence of additional cases in flocks affected by atypical scrapie using surveillance data collected in Europe in order to ascertain whether atypical scrapie, is contagious.

Results

Questionnaires were used to collect, at national level, the results of active surveillance and testing associated with flock outbreaks in 12 European countries. The mean prevalence of atypical scrapie was 5.5 (5.0-6.0) cases per ten thousand in abattoir surveillance and 8.1 (7.3-9.0) cases per ten thousand in fallen stock. By using meta-analysis, on 11 out of the 12 countries, we found that the probability of detecting additional cases of atypical scrapie in positive flocks was similar to the probability observed in animals slaughtered for human consumption (odds ratio, OR = 1.07, CI_95%: 0.70-1.63) or among fallen stock (OR = 0.78, CI_95%: 0.51-1.2). In contrast, when comparing the two scrapie types, the probability of detecting additional cases in classical scrapie positive flocks was significantly higher than the probability of detecting additional cases in atypical scrapie positive flocks (OR = 32.4, CI_95%: 20.7-50.7).

Conclusions

These results suggest that atypical scrapie is not contagious or has a very low transmissibility under natural conditions compared with classical scrapie. Furthermore this study stressed the importance of standardised data collection to make good use of the analyses undertaken by European countries in their efforts to control atypical and classical scrapie.     

Benzimidazole resistance of sheep nematodes in Norway confirmed through controlled efficacy test

ABSTRACT: BACKGROUND: Resistance against benzimidazoles (BZ) has recently been detected in Norwegian sheep flocks through a large scale prevalence survey based on the faecal egg count reduction test (FECRT). The use of this test in combination with bulk larval culture only gives an indication of which gastrointestinal nematodes genera that are involved and these results have to be confirmed by a controlled efficacy test (CET) to get accurate information about resistant nematodes populations at species level. A CET was therefore performed with larvae from two flocks where BZ resistance was previously detected through FECRT. RESULTS: The latter test confirmed the previous results in both flocks. In flock A, the BZ resistant nematode population consisted solely of Haemonchus contortus, whereas H. contortus and Teladorsagia circumcincta comprised the resistant worm population in flock B. CONCLUSIONS: Some discrepancies that have been recorded between FECRT and CET results regarding time for post-treatment coproscopical examination and a temporary suppression of faecal egg excretion are discussed.     

Epidemiological studies on foot and mouth disease and paratuberculosis in small ruminants in Tafelah and Ma’an,Jordan

A cross-sectional study was performed to investigate some epidemiological aspects of foot and mouth disease (FMD) and paratuberculosis in small ruminant flocks located in two governorates in Southern Jordan. A total of 320 sheep and 300 goats from 38 and 24, sheep and goat flocks, respectively, were randomly sampled and assayed for presence of antibodies against FMD virus and Mycobacterium paratuberculosis using commercially available kits. A structured pre-tested questionnaire was administered to collect information on flocks’ health and management. A multivariable logistic regression model was constructed to investigate risk factors associated with seropositivity to the two studied diseases. The individual prevalence of FMD and paratuberculosis in sheep was 10.4 and 22.1%, respectively. The sheep flock level seroprevalence for FMD and paratuberculosis was 44.7 and 50%, respectively. In goats, the individual prevalence of FMD and paratuberculosis was 6.3 and 18.1%, respectively. The goat flock level seroprevalence for FMD and paratuberculosis was 33.3 and 45.8%, respectively. The logistic regression model revealed mixed farming as a common risk factor for both FMD and paratuberculosis. Grazing in communal areas and addition of new animals were identified as risk factors for paratuberculosis.     

Are Obesity and Physical Activity Clustered? A Spatial Analysis Linked to Residential Density

The aim of this study was to examine spatial clustering of obesity and/or moderate physical activity and their relationship to a neighborhood's built environment. Data on levels of obesity and moderate physical activity were derived from the results of a telephone survey conducted in 2006, with 1,863 survey respondents in the study sample. This sample was spread across eight suburban neighborhoods in Metro Vancouver. These areas were selected to contrast residential density and income and do not constitute a random sample, but within each area, respondents were selected randomly. Obesity and moderate physical activity were mapped to determine levels of global and local spatial autocorrelation within the neighborhoods. Clustering was measured using Moran's I at the global level, Anselin's Local Moran's I at the local level, and geographically weighted regression (GWR). The global‐level spatial analysis reveals no significant clustering for the attributes of obesity or moderate physical activity. Within individual neighborhoods, there is moderate clustering of obesity and/or physical activity but these clusters do not achieve statistical significance. In some neighborhoods, local clustering is restricted to a single pair of respondents with moderate physical activity. In other neighborhoods, any moderate local clustering is offset by negative local spatial autocorrelation. Importantly, there is no evidence of significant clustering for the attribute of obesity at either the global or local level of analysis. The GWR analysis fails to improve significantly upon the global model—thus reinforcing the negative results. Overall, the study indicates that the relationship between the urban environment and obesity is not direct.     

Seroprevalence of ovine paratuberculosis infection in the Northeast of Portugal

A survey to estimate the prevalence of ovine paratuberculosis in sheep flocks was conducted in the Northeast of Portugal. In total, 3900 samples of sheep older than 2 years belonging to 150 sheep flocks from 12 different territorial Livestock Farmers Organizations (OPP) were investigated for the presence of antibodies against Mycobacterium avium subspecies paratuberculosis using a commercial enzyme-linked immunosorbent assay (ELISA) test. Seventy (46.7%) flocks had one or more serologically positive animals. The individual paratuberculosis prevalence was 3.7% (144/3900), with values ranging from 0.0 to 10.3% per flock. Statistically significant differences between OPP, herd size and the presence of clinical signs was observed. According to the test sensitivity and specificity claimed by the manufacturer, the true prevalence in the Northeast of Portugal was calculated as 6.4%. In summary, a small percentage of animals and a high percentage of flocks in the Northeast of Portugal were serologically positive.     

Scrapie prevalence in sheep of susceptible genotype is declining in a population subject to breeding for resistance

Background  

Susceptibility of sheep to scrapie infection is known to be modulated by the PrP genotype of the animal. In the Netherlands an ambitious scrapie control programme was started in 1998, based on genetic selection of animals for breeding. From 2002 onwards EU regulations required intensive active scrapie surveillance as well as certain control measures in affected flocks.     

Flock Health Indicators and Campylobacter spp. in Commercial Housed Broilers Reared in Great Britain

This study investigated the relationship between flock health and Campylobacter infection of housed commercial broilers in Great Britain. Thirty ceca were collected at slaughter from batches of broilers from 789 flocks, at either full or partial depopulation, between December 2003 and March 2006 and examined individually for Campylobacter by direct plating onto selective media. Management and health data were collected from each flock and included information on mortality or culling during rearing, the number of birds rejected for infectious or noninfectious causes at slaughter, the proportion of birds with digital dermatitis (also termed hock burn), and other general characteristics of the flock. Campylobacter spp. were isolated from 280 (35%) flocks. The relationship between bird health and welfare and Campylobacter status of flocks was assessed using random-effects logistic regression models, adjusting for region, month, year, and rearing regime. Campylobacter-positive batches of ceca were associated with higher levels of rejection due to infection (odds ratio [OR], 1.5; 95% confidence interval [CI_95%], 0.98 to 2.30) and digital dermatitis (OR, 2.08; CI_95%, 1.20 to 3.61). Furthermore, higher levels of these conditions were also associated with the highest-level category of within-flock Campylobacter prevalence (70 to 100%). These results could indicate that improving health and welfare may also reduce Campylobacter in broilers.     

Evaluation of PCR for detection of Campylobacter in a national broiler surveillance programme in Denmark

AIMS: To develop and evaluate a rapid and sensitive PCR method for detection of Campylobacter spp. directly from chicken faeces. METHODS AND RESULTS: DNA was isolated from faecal swabs using magnetic beads followed by PCR using a prealiquoted PCR mixture, which had been stored in the freezer. The result could be obtained in <6 h. The method was evaluated on 1282 samples from the Danish surveillance programme for Campylobacter in broilers by comparing with conventional culture. The diagnostic specificity was calculated to be 0.99. The detection limits of the PCR method and of the conventional culture were compared using spiked control material. For both methods the detection limit was 36 CFU ml-1. CONCLUSIONS: It was concluded that the PCR proved useful for detection of Campylobacter in pooled cloacal swabs from broilers. SIGNIFICANCE AND IMPACT OF THE STUDY: By taking cloacal samples in the broiler flocks the technique can be used as an important tool for planning and directing the broiler slaughtering process. This will be a great help in minimizing the risk of contaminating Campylobacter-free flocks at the abattoir.     

An evaluation of landslide susceptibility using probability statistic modeling and GIS's spatial clustering analysis

As landslides caused multiple casualties and destructions on a global scale, various models were applied to landslide susceptibility evaluation. In this study, a probability statistic model called the certain factor was adopted to assess the landslide susceptibility of Danba, a county in southwestern China, where the landslide events occur frequently but were poorly understood in regional landslide susceptibility. With the validation of area under the prediction rate curve, the resulting susceptibility map has the accuracies of 0.8211 and 0.8288 in experiment area and verification area, respectively. The validated assessment result was further processed to identify landslide-prone areas with the aid of the spatial clustering analysis of geographic information system. Two clustering indexes including Moran's I statistic and local indicator of spatial association (LISA) were involved. The Moran's I index of 0.959 and the LISA identification result accordant with previous investigations proved that the proposed method was rational and efficient to find the landslide-prone regions and make relevant decisions.     

The estimation of pooled-sample sensitivity for detection of Salmonella in turkey flocks

Aims:  To investigate the effectiveness of pooled sampling methods for detection of Salmonella in turkey flocks.
Methods and Results:  Individual turkey droppings were taken from 43 flocks, with half the dropping tested for S almonella as an individual sample and the other half included in a pool of five. A pair of boot swabs and a dust sample were also taken from each flock. The results were analysed using Bayesian methods in the absence of a gold standard. This showed a dilution effect of mixing true-positive with negative samples, but even with this the pooled faecal samples were found to be a highly efficient method of testing compared with individual faecal samples. The more samples included in the pool, the more sensitive the pooled sampling method was predicted to be. The sensitivity of dust sampling was much more sensitive than faecal sampling at low prevalence.
Conclusions:  Pooled faecal sampling is an efficient method of Salmonella detection in turkey flocks. The additional testing of a dust sample greatly increased the effectiveness of sampling, especially at low prevalence.
Significance and Impact of the Study:  This is the first study to relate the sensitivity of the sampling methods to the within-flock prevalence.     

Quantitative estimation of genetic risk for atypical scrapie in French sheep and potential consequences of the current breeding programme for resistance to scrapie on the risk of atypical scrapie

Background

Since 2002, active surveillance programmes have detected numerous atypical scrapie (AS) and classical scrapie cases (CS) in French sheep with almost all the PrP genotypes. The aim of this study was 1) to quantify the genetic risk of AS in French sheep and to compare it with the risk of CS, 2) to quantify the risk of AS associated with the increase of the ARR allele frequency as a result of the current genetic breeding programme against CS.

Methods

We obtained genotypes at codons 136, 141, 154 and 171 of the PRNP gene for representative samples of 248 AS and 245 CS cases. We used a random sample of 3,317 scrapie negative animals genotyped at codons 136, 154 and 171 and we made inferences on the position 141 by multiple imputations, using external data. To estimate the risk associated with PrP genotypes, we fitted multivariate logistic regression models and we estimated the prevalence of AS for the different genotypes. Then, we used the risk of AS estimated for the ALRR-ALRR genotype to analyse the risk of detecting an AS case in a flock homogenous for this genotype.

Results

Genotypes most at risk for AS were those including an AFRQ or ALHQ allele while genotypes including a VLRQ allele were less commonly associated with AS. Compared to ALRQ-ALRQ, the ALRR-ALRR genotype was significantly at risk for AS and was very significantly protective for CS. The prevalence of AS among ALRR-ALRR animals was 0.6‰ and was not different from the prevalence in the general population.

Conclusion

In conclusion, further selection of ALRR-ALRR animals will not result in an overall increase of AS prevalence in the French sheep population although this genotype is clearly susceptible to AS. However the probability of detecting AS cases in flocks participating in genetic breeding programme against CS should be considered.     

Usefulness and validation of a coproantigen test for dog echinococcosis screening in the consolidation phase of hydatid control in Neuquén,Argentina

Hydatidosis is endemic in Neuquén, Patagonia, Argentina, even though sanitary authorities have been performing a control programme since 1970. At present, the programme is in consolidation phase, and dogs have being evaluated by arecoline purgation. The aims of this study were to evaluate diagnostic performance of a coproantigen (CAg) ELISA test developed “in house” and to assess CAg detection in prepatent period. We examined 8 dogs experimentally infected with Echinococcus granulosus and 403 rural dogs in an endemic area in Neuquén using CAg ELISA test and arecoline purgation. Within the experimental dog group, sensitivity and specificity of the test were 93.6% and 88.5% respectively. In rural dogs group, the overall prevalence of canine echinococcosis was 3.7% using arecoline purgation and 12.4% by the CAg test; sensitivity and specificity of the test using arecoline purge as standard were 73.3% and 89.9% respectively. Possible cross reactions in CAg test were evaluated in rural dogs: CAg was undetectable in 96.4% of the dogs infected only with taeniids non-E. granulosus, and in 90.1% of dogs infected with non-taeniid helminths. The CAg test could detect infections within prepatent period and produced negative results after worm expulsion. Our test showed adequate diagnostic performance with experimentally and naturally infected dogs, in the epidemiological situation of Neuquén. Employment of this sensitive and practical method for surveillance in the control programme in Neuquén would improve screening of canine echinococcosis by detecting infected dogs even with low burdens or within prepatent period.     

Evidence that certain clones of Campylobacter jejuni persist during successive broiler flock rotations

Through the national surveillance program for Campylobacter spp., nine broiler chicken farms that were infected with Campylobacter jejuni in at least five rotations in 1998 were identified. One additional farm, located at the island of Bornholm where divided slaughter is used extensively, was also selected. Twelve broiler houses located on 10 farms were included in the study. The C. jejuni isolates collected from the selected houses during the surveillance were typed using fla typing and macrorestriction profiling (MRP), and a subset of the isolates, representing each of the identified clones, was serotyped according to the Penner scheme. Pulsed-field gel electrophoresis typing using SmaI and KpnI revealed that the majority of houses (11 of 12) carried identical isolates in two or more broiler flocks. Such persistent clones were found in 63% of all flocks (47 of 75). The majority of persistent clones (7 of 13) had fla type 1/1, but MRPs distinguished between isolates from different houses, and fla type 1/1 clones belonged to different serotypes. Seven houses carried persistent clones that covered an interval of at least four broiler flock rotations, or at least one half year. The dominant fla type (1/1) was represented by 44% of isolates, or by at least one isolate from 31 of 62 broiler flocks. This significantly exceeded the prevalence of fla type 1/1 C. jejuni isolates that we have estimated from other studies and suggests that isolates carrying this fla type are overrepresented in flocks with recurrent Campylobacter problems. The MRPs of clones belonging to fla type 1/1 serotype O:2 isolated from persistently infected flocks shared a high percentage of bands compared to the remaining isolates, indicating that some clones that have the ability to cause persistent infections in broiler farms are highly related to each other.     

Spatial Clustering of All-Cause and HIV-Related Mortality in a Rural South African Population (2000–2006)

Background

Sub-Saharan Africa bears a disproportionate burden of HIV infection. Knowledge of the spatial distribution of HIV outcomes is vital so that appropriate public health interventions can be directed at locations most in need. In this regard, spatial clustering analysis of HIV-related mortality events has not been performed in a rural sub-Saharan African setting.

Methodology and Results

Kulldorff’s spatial scan statistic was used to identify HIV-related and all-cause mortality clusters (p<0.05) in a population-based demographic surveillance survey in rural KwaZulu Natal, South Africa (2000–2006). The analysis was split pre (2000–2003) and post (2004–2006) rollout of antiretroviral therapy, respectively. Between 2000–2006 a total of 86,175 resident individuals ≥15 years of age were under surveillance and 5,875 deaths were recorded (of which 2,938 were HIV-related) over 343,060 person-years of observation (crude all-cause mortality rate 17.1/1000). During both time periods a cluster of high HIV-related (RR = 1.46/1.51, p = 0.001) and high all-cause mortality (RR = 1.35/1.38, p = 0.001) was identified in peri-urban communities near the National Road. A consistent low-risk cluster was detected in the urban township in both time periods (RR = 0.60/0.39, p = 0.003/0.005) and in the first time period (2000–2003) a large cluster of low HIV-related and all-cause mortality in a remote rural area was identified.

Conclusions

HIV-related and all-cause mortality exhibit strong spatial clustering tendencies in this population. Highest HIV-related mortality and all-cause mortality occurred in the peri-urban communities along the National Road and was lowest in the urban township and remote rural communities. The geography of HIV-related mortality corresponded closely to the geography of HIV prevalence, with the notable exception of the urban township where high HIV-related mortality would have been expected on the basis of the high HIV prevalence. Our results suggest that HIV treatment and care programmes should be strengthened in easy-to-reach high density, peri-urban populations near National Roads where both HIV-related and all-cause mortality are highest.