Liver fluke (Fasciola hepatica) infection in cattle in Northern Ireland: a large-scale epidemiological investigation utilising surveillance data

Estimation of diagnostic sensitivity and specificity of abattoir registrations and bulk tank milk ELISA as herd-level tests for Fasciola hepatica using Bayesian latent class modelling

The common liver fluke, Fasciola hepatica, is a trematode parasite found worldwide, typically with a focal distribution due to its requirement for suitable climatic and environmental conditions to complete its lifecycle. Bovine fasciolosis causes suboptimal production and economic losses, including liver condemnation at slaughter. The lack of reliable diagnostic methods is a disadvantage to the increasing demand for surveillance and control. The aim of this study was to evaluate the diagnostic accuracy of bulk tank milk (BTM) antibody testing and aggregated abattoir registrations (AAR) of liver fluke as herd-level tests for F. hepatica infection using Bayesian latent class models. Data from the abattoirs in 2019-2021 and BTM, sampled in the winter of 2020/2021, were collected from 437 herds on the southwest coast of Norway. The BTM samples were analysed with the SVANOVIR® F. hepatica-Ab ELISA test, with results given as an optical density ratio (ODR), and later dichotomized using the recommended cut-off value from the test manufacturer (ODR ≥0.3). Based on the BTM ELISA test, 47.8% of the herds tested positive. The AAR test was defined as the herd-level proportion of female slaughtered animals registered with liver fluke infection during the study period. For this test, three cut-offs were used (a proportion of 0.05, 0.1 and 0.2). The herds were split into two subpopulations ("Coastal" and "Inland"), which were expected to differ in true prevalence of F. hepatica infection based on climate-related and geographical factors. The diagnostic accuracies of both tests were estimated using Bayesian latent class models with minimally informative priors. Post-hoc analysis revealed that the maximum sum of sensitivity (Se) and specificity (Sp) of the tests was achieved with a herd-level proportion of ≥0.1 registered with liver fluke as the AAR test. Using this cut-off, the median estimate for the diagnostic accuracy of the BTM ELISA was 90.4% (84.0-96.2 95% Posterior Credible Interval (PCI)) for Se and 95.3% (90.6-100% PCI) for Sp, while the median estimate of Se for AAR was 87.5% (81.4-93.1% PCI) and the median estimate of Sp for AAR was 91.0% (85.2-96.5% PCI). The cut-off evaluation of the SVANOVIR® F. hepatica-Ab ELISA test for BTM confirmed the manufacturer's recommended cut-off of ODR ≥0.3 to denote positive and negative herds. This study suggests that AAR and BTM ELISA test can be used as herd-level tools to monitor liver fluke infection, so that appropriate interventions against infection can be implemented as necessary.

Next-generation sequencing technologies for helminth diagnostics and surveillance in ruminants: shifting diagnostic barriers

Helminth infections in grazing ruminants are a major issue for livestock farming globally, but are unavoidable in outdoor grazing systems and must be effectively managed to avoid deleterious effects to animal health, and productivity. Next-generation sequencing (NGS) technologies are transforming our understanding of the genetic basis of anthelmintic resistance (AR) and epidemiological studies of ruminant gastrointestinal parasites. They also have the potential to not only help develop and validate molecular diagnostic tests but to be directly used in routine diagnostics integrating species-specific identification and AR into a single test. Here, we review how these developments have opened the pathway for the development of multi-AR and multispecies identification in a single test, with widespread implications for sustainable livestock farming for the future.

Coproprevalence, seroprevalence, and geographic distribution of Fasciola spp. infection in beef and dairy cattle in Pak Chong highland, Nakhon-Ratchasima Province, Northeast Thailand

Fasciola spp. is a major livestock parasite, especially in cattle, water buffalo, sheep, and goats. Infection reduces animal productivity, e.g., meat, dairy, wool and might cause death. In Thailand, reports of Fasciola spp. infection in livestock, especially dairy and beef cattle, are sparse. Pakchong district in Nakhon Ratchasima province is one of Thailand's largest farming areas for dairy and beef cattle, but the prevalence of Fasciola spp. infection has never been reported in this district. The landscape of this area is mainly a hilltop plateau with many water sources suitable for the development of lymnaeid snails, the intermediate host of Fasciola spp., which are essential for the parasite life cycle. This study surveyed the copro- and seroprevalence of Fasciola spp. infection in dairy and beef cattle farmed in Pakchong district by microscope-based examination, PCR, and indirect ELISA. Associated risk factors and geographic information data were collected and analyzed. Paired stool and serum samples were collected from 102 dairy cattle and 99 beef cattle from April to November 2021. Sample analyses demonstrated a high prevalence of Fasciola spp. infection, especially in beef cattle. The overall copro-prevalence was 5.97%, with 0.99% in dairy cattle and 11.11% in beef cattle. The overall seroprevalence was 23.88%, with 2.94% in dairy cattle and 45.45% in beef cattle. Moreover, the data indicated that infection status was not correlated with animal sex and age whereas consumption of natural grasses, water resources, housing floor, and farming system were significant risk factors. Data analysis by a geographic information system (GIS) demonstrated that an associated risk could be farmed in lowering areas, especially in Chan Thuck, Nong Sa Rai, and Khlong Muang subdistricts. In conclusion, this study reports the prevalence of Fasciola spp. infection in cattle in a major farming area of Thailand which could be beneficial for designing parasite control policies in this region as well as adapting this knowledge to other Fasciola spp. endemic areas.

A survey for antibodies against Fasciola hepatica in cattle and sheep in finland indicates a low level of exposure

BACKGROUND

Fasciolosis is a parasitic infection caused by the liver fluke Fasciola hepatica that can have a major economic impact on livestock industry. The prevalence of the disease has recently been increasing in many North European countries. The objective of this study was to determine the prevalence of antibody against F. hepatica in Finnish cattle herds and sheep flocks during 2019 by using a commercial enzyme-linked immunosorbent assay (ELISA). Randomly selected bulk tank milk samples were obtained from 660 dairy herds. Blood samples were collected at slaughterhouses from 1944 suckler cows from 309 herds and from 1120 sheep from 95 flocks.

RESULTS

Antibodies against F. hepatica were found in 0.45% (95% confidence interval (CI): 0.15-1.33) of the dairy herds and 0.97% (95% CI: 0.33-2.82) of the suckler cow herds. The seropositive herds were located in eastern and central Finland. None of the sampled sheep flocks tested had antibodies against F. hepatica (95% CI: 0-3.89). The results of the assays were compared with meat inspection data received from the slaughterhouses. All positive herds also had liver condemnations due to F. hepatica based on the meat inspection reports.

CONCLUSIONS

Compared to other North European countries, the prevalence of fasciolosis in Finland can be considered low, and according to meat inspection reports, there are no indications of the prevalence increasing in Finland.

Fascioliasis may promote tuberculous infectivity in small ruminants

Fascioliasis and bovine tuberculosis (TB) are global impediments to livestock development. We investigated the co-infectivity of fascioliasis and TB in small ruminants at slaughter. A total of 84 goats and 16 sheep were investigated from different slaughter houses in Mymensingh city, Bangladesh from June 2019 to February 2020. Grossly, acute fascioliasis was characterized by hemorrhagic tracts in the liver and chronic fascioliasis with biliary cirrhosis and pipe-stem liver. Grossly, seven goats and two sheep were associated with the acute and sixty goats and seven sheep were associated with the chronic phase of fascioliasis. Five goats’ livers showed both the acute and chronic phases of fascioliasis. In TB, granulomas with central core of caseous necrosis were seen in the lymph nodes (21), livers (10) and lungs (01) of goats or in the lymph nodes (03) and liver (01) of sheep. Histopathologically, biliary cirrhosis was seen in fascioliasis and granuloma, caseous necrosis and calcification in TB. In co-infection revealed granuloma (TB) with acid-fast bacilli and widespread biliary cirrhosis in the livers of goats (14) and sheep (02). The fragments of the 16S rRNA gene (372 bp, M. tuberculosis complex) and MPB83 gene (600 bp, M. bovis) were detected in the lymph nodes, livers and lungs using polymerase chain reaction. This study showed the existence of co-infectivity of Fasciola and M. bovis in goats and sheep in Bangladesh. Chronic fascioliasis may be associated with establishing tuberculous infection in small ruminants. Therefore, extremely zoonotic bovine TB control programs require active management of fascioliasis.

Timing of Transcriptomic Peripheral Blood Mononuclear Cell Responses of Sheep to Fasciola hepatica Infection Differs From Those of Cattle, Reflecting Different Disease Phenotypes

Infection with the zoonotic trematode Fasciola hepatica, common in many regions with a temperate climate, leads to delayed growth and loss of productivity in cattle, while infection in sheep can have more severe effects, potentially leading to death. Previous transcriptomic analyses revealed upregulation of TGFB1, cell death and Toll-like receptor signalling, T-cell activation, and inhibition of nitric oxide production in macrophages in response to infection. However, the differences between ovine and bovine responses have not yet been explored. The objective of this study was to further investigate the transcriptomic response of ovine peripheral blood mononuclear cells (PBMC) to F. hepatica infection, and to elucidate the differences between ovine and bovine PBMC responses. Sixteen male Merino sheep were randomly assigned to infected or control groups (n = 8 per group) and orally infected with 120 F. hepatica metacercariae. Transcriptomic data was generated from PBMC at 0, 2 and 16 weeks post-infection (wpi), and analysed for differentially expressed (DE) genes between infected and control animals at each time point (analysis 1), and for each group relative to time 0 (analysis 2). Analysis 2 was then compared to a similar study performed previously on bovine PBMC. A total of 453 DE genes were found at 2 wpi, and 2 DE genes at 16 wpi (FDR < 0.1, analysis 1). Significantly overrepresented biological pathways at 2 wpi included role of PKR in interferon induction and anti-viral response, death receptor signalling and RIG-I-like receptor signalling, which suggested that an activation of innate response to intracellular nucleic acids and inhibition of cellular apoptosis were taking place. Comparison of analysis 2 with the previous bovine transcriptomic study revealed that anti-inflammatory response pathways which were significantly overrepresented in the acute phase in cattle, including IL-10 signalling, Th2 pathway, and Th1 and Th2 activation were upregulated only in the chronic phase in sheep. We propose that the earlier activation of anti-inflammatory responses in cattle, as compared with sheep, may be related to the general absence of acute clinical signs in cattle. These findings offer scope for "smart vaccination" strategies for this important livestock parasite.

Comparison of Liver Condemnation and Bile Microscopy As Tools to Estimate Fasciola hepatica Prevalence and Burden in the Anta Province of Cusco in Peru

Fascioliasis is a zoonotic infection linked to significant economic losses in the livestock industry. Infection prevalence and estimated financial burden vary across locations owing to different diagnostic tests used. The accuracy of liver condemnation to estimate the prevalence and costs of fascioliasis has seldom been evaluated. We performed a pilot study to determine the prevalence and burden of Fasciola hepatica infection among cattle slaughtered at the municipal abattoir in the Anta province of the Cusco highlands in Peru. We compared liver condemnation with bile microscopy for the diagnosis of infection and prediction of carcass weight. Data were collected from 2009 slaughtered cattle for 1 year. The overall prevalence of Fasciola infection by bile microscopy was 62.5% (1247/2009). A higher prevalence was observed after the rainy season from March to August than from September to February (p < 0.01). Fascioliasis prevalence during the first 6 months was 77.4% (714/923), combining the results of condemnation and microscopy. Bile microscopy diagnosed more infections than liver condemnation (62.7% (579/923) versus 55.4% (511/923), McNemar test p < 0.01). The agreement of the bile microscopy testing with liver condemnation was fair (κ = 0.247). Animal age, gender, breed, and liver condemnation predicted carcass weight [F (df 4, 704) = 61.1, p < 0.001]. Liver condemnation and bile microscopy are complementary tools for evaluation of the prevalence and burden of fascioliasis in livestock. Large scale studies are warranted to confirm our results.

The First Report of Ruminant Fascioliasis in Sabah, East Malaysia

Ruminant fascioliasis is a neglected yet important tropical zoonotic disease that affects both the livestock and humans. The disease has a worldwide distribution, and Malaysia is one of the countries that face problems related to this parasite. These retrospective studies were conducted in Makmal Diagnosa Veterinar Kota Kinabalu (MDVKK) and Sabah Meat Technology Centre (SMTC), Kinarut over a period of eleven years (2008–2018). For MDVKK, the overall occurrence of fascioliasis was 24.9%. Out of 769 cattle's and buffaloes' faecal samples submitted, Fasciola spp ova were detected in 189 of the samples. A total of 2297 cattle, buffaloes, and goats were slaughtered at SMTC over that period, and 21 livers were condemned due to fascioliasis, giving the total occurrence of 0.91%. This investigation provides information on the occurrence of ruminant fascioliasis in Sabah, East Malaysia. The results from this study highlight the alarming incidence of fascioliasis and the urgent need for action to control this neglected tropical disease in East Malaysia.

A holistic model to assess risk factors of fasciolosis in Ankole cattle

In recent decades, remote sensing (RS) technology and geographical information systems (GIS) were increasingly used as tools for epidemiological studies and the control of zoonotic diseases. Fasciolosis, a zoonotic disease caused by a trematode parasite (Fasciola spp.), is a good candidate for the application of RS and GIS in epidemiology because it is strongly influenced by the environment, i.e. the habitat of the intermediate host. In this study, we examined variables which may increase the fasciolosis risk of Ankole cattle in the degraded and overgrazed Mutara rangelands of north-eastern Rwanda. The risk variables considered included three environmental variables (normalized difference vegetation index, NDVI; normalized difference moisture index, NDMI; normalized difference water index, NDWI), two landscape metric variables (rangeland proportion, building density), two geological variables (poorly-drained soil proportion, elevation) and three animal husbandry variables (herd size, adult proportion and the body condition score). Fasciola spp. prevalence was used as the dependent variable, sampling season as a fixed factor and four principal components (PCs, condensed from the ten risk variables) as covariates in a univariate General Linear Model. Fasciola spp. prevalence was positively correlated to rangeland proportion, cattle herd size in rural areas, adult proportion and individual body condition. Moreover, high Fasciola spp. prevalence was found in densely vegetated areas with high moisture (high values of NDVI and NDMI), in combination with large proportions of poorly-drained soil at low elevations. Future investigations should focus on increased sampling across the Mutara rangelands to prepare a predictive, spatial fasciolosis risk map that would help to further improve sustainable land-use management.

Prevalence of fasciolosis (Liver flukes) infection in cattle in Zamfara, Nigeria: A slaughterhouse surveillance data utilizing postmortem examination

Bovine fasciolosis, caused by Fasciola gigantica (F. gigantica) and rarely F. hepatica, is an economically important disease affecting cattle in tropical Africa. The aims of this study were to determine a year prevalence of bovine fasciolosis and correlate determinants of infection in slaughtered cattle at the municipal abattoir in Zamfara, Nigeria. Fasciola gigantica was detected in 15% (1740/11,562) cattle slaughtered during a daily postmortem examination (PME) between November 2016 and October 2017. This approach demonstrated an increase risk of liver fluke infection in older cattle (p = 0.001, AOR = 1.476, 95% CI: 1.188-1.832) and during rainfall (p = 0.003, AOR = 1.604, 95% CI: 1.176-2.187). Liver condemnation had been significantly found in hot-dry season (p ≤0.001, AOR = 0.518, 95% CI: 0.417-0.643) and adult cattle (p = 0.003, AOR = 1.726, 95% CI: 0.586-0.899). This study is an account of bovine fasciolosis prevalence and infection dynamics in part of the northwest region of Nigeria, which provides preliminary information for further studies to guide the design of appropriate control steps to lower the impact of the disease and safeguard public health.

Fasciola hepatica infection in cattle and the use of simulation models for endemic areas

Fasciolosis is a food-borne disease that causes great distress to a range of hosts, including humans. The objectives of this study were to (1) evaluate the liver damage and carcass weight of cattle naturally infected with Fasciola hepatica from the state of Rio Grande do Sul (RS), Brazil, and to (2) determine the distribution of adult flukes in 12,236 cattle liver from RS. The data from these experiments were used to calculate the overall economic loss due to F. hepatica infection. Eighteen adult Polled Hereford cows were divided into a triclabendazole (TbG) and a F. hepatica-positive group (FhG). For Experiment 1, a generalized linear mixed model revealed a statistical difference in carcass weight (49.8 kg) between TbG and FhG. The Monte Carlo analysis also revealed that the animals' weight differences were due to the disease. For Experiment 2, the prevalence of infected livers was above 16% (1904/12,236), mostly (20.1%) from the south-west region of RS. The Susceptible-infected-recovered (SIR) epidemic model revealed the evolution of the infection using a high infectivity and low recovery rate. Other distinctive scenarios that occur in RS were also established with different rates of infectivity. The economic assessment showed a potential loss of US$45 million to the beef cattle industry of RS, with an overall State cost of US$90.3 million. These novel findings reveal the importance of fasciolosis infection, which can cause a significant health condition and poor animal welfare.

Habitat and host factors associated with liver fluke (Fasciola hepatica) diagnoses in wild red deer (Cervus elaphus) in the Scottish Highlands

BACKGROUND

Red deer (Cervus elaphus) are a common wild definitive host for liver fluke (Fasciola hepatica) that have been the subject of limited diagnostic surveillance. This study aimed to explore the extent to which coprological diagnoses for F. hepatica in red deer in the Scottish Highlands, Scotland, are associated with variability among hosts and habitats.

METHODS

Our analyses were based on coproantigen ELISA diagnoses derived from faecal samples that were collected from carcasses of culled deer on nine hunting estates during two sampling seasons. Sampling locations were used as centroids about which circular home ranges were quantified. Data were stratified by season, and associations between host, hydrological, land cover and meteorological variables and binary diagnoses during 2013-2014 (n = 390) were explored by mixed effect logistic regression. The ability of our model to predict diagnoses relative to that which would be expected by chance was quantified, and data collected during 2012-2013 (n = 289) were used to assess model transferability.

RESULTS

During 2013-2014, habitat and host characteristics explained 28% of variation in diagnoses, whereby half of the explained variation was attributed to differences among estates. The probability of a positive diagnosis was positively associated with the length of streams in the immediate surroundings of each sampling location, but no non-zero relationships were found for land cover or lifetime average weather variables. Regardless of habitat, the probability of a positive diagnosis remained greatest for males, although males were always sampled earlier in the year than females. A slight decrease in prediction efficacy occurred when our model was used to predict diagnoses for out-of-sample data.

CONCLUSIONS

We are cautious to extrapolate our findings geographically, owing to a large proportion of variation attributable to overarching differences among estates. Nevertheless, the temporal transferability of our model is encouraging. While we did not identify any non-zero relationship between meteorological variables and probability of diagnosis, we attribute this (in part) to limitations of interpolated meteorological data. Further study into non-independent diagnoses within estates and differences among estates in terms of deer management, would improve our understanding of F. hepatica prevalence in wild deer.

The impact of liver fluke infection on steers in Ireland: A meta-analytic approach

Post-mortem liver inspection results together with production parameters are often used to estimate the impact of liver fluke infection on farm animal populations. However, post mortem liver inspection is an imperfect method of determining the liver fluke infection status of cattle. This work estimates the difference in mean lifetime weight gain at 819 days (ΔLWG₈₁₉) between steers assigned liver fluke negative (LFN) and liver fluke positive (LFP) status at post-mortem meat inspection, quantifies the potential impact of imperfect sensitivity and specificity on these results and estimates the economic impact of these differences. The study population is 32,007 steers that never moved from their birth herd in the Republic of Ireland and were slaughtered in one of two Irish meat processors in 2014. Individual animal-level data are used to generate 46 county - processor level estimates of ΔLWG₈₁₉. Standard errors and confidence intervals for these estimates are derived using bootstrapping. A meta-analytic approach is then used to obtain 3 overall estimates of the effect of liver fluke status on the ΔLWG₈₁₉ in all the county - processor combinations, assuming post - mortem liver inspection Se = Sp = 1, 0.99 and 0.95. A random effects model is used and 95% prediction intervals (95% PI) are calculated. Assuming Se = Sp = 1 for post - mortem liver inspection, the random effects summary estimate of ΔLWG₈₁₉ (ΔLWG_819(RE)) is 36 kg (95% PI: -1, 73). There is a minor change in ΔLWG_819(RE) (38 kg, 95% PI: -1, 77) when Se = Sp = 0.99 is assumed but this increases to 46 kg (95% PI: -2, 94) assuming Se = Sp = 0.95. The corresponding cost in euros of these differences between the LFN and LFP steers, assuming a price per kg of €3.90, are €77.01 (95% PI: -2.57, 156.37), €80.65 (95% PI: -3.43, 164.74) and €98.67 (95% PI: -5.15, 202.27) respectively. Our results demonstrate an association between liver fluke infection and reduced weight gain. We show that the effect of liver fluke infection on weight gain in cattle is underestimated due to misclassification resulting from imperfection in post mortem meat inspection. These findings will aid researchers, farmers and veterinary practitioners to make informed decisions on the control of liver fluke on farms.

A mechanistic hydro-epidemiological model of liver fluke risk

The majority of existing models for predicting disease risk in response to climate change are empirical. These models exploit correlations between historical data, rather than explicitly describing relationships between cause and response variables. Therefore, they are unsuitable for capturing impacts beyond historically observed variability and have limited ability to guide interventions. In this study, we integrate environmental and epidemiological processes into a new mechanistic model, taking the widespread parasitic disease of fasciolosis as an example. The model simulates environmental suitability for disease transmission at a daily time step and 25 m resolution, explicitly linking the parasite life cycle to key weather–water–environment conditions. Using epidemiological data, we show that the model can reproduce observed infection levels in time and space for two case studies in the UK. To overcome data limitations, we propose a calibration approach combining Monte Carlo sampling and expert opinion, which allows constraint of the model in a process-based way, including a quantification of uncertainty. The simulated disease dynamics agree with information from the literature, and comparison with a widely used empirical risk index shows that the new model provides better insight into the time–space patterns of infection, which will be valuable for decision support.

Fascioliasis in buffaloes: A 5-year forecast analysis of the disease based on a 15-year survey in Brazil

In South America, fascioliasis caused by the trematode Fasciola hepatica is an anthropozoonosis disease associated with significant economic losses and poor animal welfare. The objective of this study was to determine the prevalence of F. hepatica in the liver of buffaloes slaughtered from 2003 to 2017 in Brazil, and to perform a forecast analysis of the disease for the next five years using the Autoregressive Integrated Moving Average (ARIMA) model. Data analysis revealed an incidence of 7,187 cases out of 226,561 individuals. The disease presented a considerable interannual variation (p<0.005). Fasciola hepatica was more prevalent in the southern states of Brazil; Paraná, Rio Grande do Sul, and Santa Catarina, presenting 11.9, 7.7, and 3.2% of infected livers, respectively. The high frequency of liver condemnation in Paraná was influenced by weather conditions. The ARIMA models calculated a constant trend of the disease, depicting an average of its future prevalence. The models also described a worse-case and a positive-case scenario, calculating the effects of intervention measurements. In reality, there is an urgent need for regular diagnostic in the animals (fecal and immune diagnose) and in the environment (intermediate host), in order to avoid the high rates of infection.

Prevalence of fasciolosis in slaughtered dairy cattle from São Miguel Island, Azores, Portugal

Fasciolosis, caused by the trematode Fasciola hepatica, is considered one of the most important parasitosis in dairy cattle due to significant economic losses. The main objectives of this study were to determine the prevalence of fasciolosis in dairy cattle slaughtered at São Miguel Island (SMI) slaughterhouse and to ascertain areas (parishes and dairy herds), within the island, with highest risk for fasciolosis. The association among cattle age and weight with the occurrence of fasciolosis was also determined. From a sample of 24,389 cattle slaughtered in two years (2015-2016), a total of 1134 dairy cattle livers were inspected and, during this period, 531 were positive to fasciolosis and 603 presented no typical fasciolosis lesions. This study showed that fasciolosis has a broad geographical distribution on SMI and that is also found in cattle from other islands of the Azores archipelago, namely Flores Island. Although there were no significant differences in weight between healthy animals and parasitized ones, we observed that the older animals present a greater level of liver lesions and a higher level of parasitization, reflecting their longer period of exposure to the risk factor (ingestion of metacercariae in pastures infested by Galba truncatula).

A post-mortem study of bovine fasciolosis in the Mitidja (north center of Algeria): prevalence, risk factors, and comparison of diagnostic methods

The present study was conducted to determine the prevalence of fasciolosis and investigate the associated risk factors (sex, age, and season) in slaughtered cattle of the Mitidja area. This survey also aimed to compare three diagnostic methods: liver inspection, microscopic bile examination, and ELISA test. Liver and bile of 1400 cattle were examined for the presence of adult and eggs of Fasciola hepatica, respectively. Based on the results obtained by liver and bile examination, a subset of 206 cattle from the 1400 was selected for antibodies detection using the ELISA test. Liver inspection and microscopic bile examination showed prevalences of 2.86% and 5.50%, respectively. The difference between the two methods was highly significant (p < 0.001). The overall prevalence of bovine fasciolosis found by both methods was 6.07%. The disease was more prevalent in females (11.96%) than in males (2.43%), and in older cattle (12.30%) than in younger ones (2.36%). The ELISA test showed some conflicting results: 23.61% of cattle previously diagnosed positive with liver inspection and bile examination were found seronegative, and 3.73% of cattle previously diagnosed negative were found to be seropositive. The sensitivity and specificity of microscopic bile examination were respectively 80% (CI 65.2-89.5%) and 96.7% (CI 95.6-97.5%) as compared with the liver inspection. Likewise, this same method has a sensitivity of 81.36% (CI 69.6-89.3%) and a specificity of 88.97% (CI 82.8-93.1%) as compared with the ELISA test. Our results show that microscopic bile examination is able to detect more infected cattle than liver inspection. In addition to being simple, fast, inexpensive, sensitive, and specific, it is an effective method for the diagnosis of fasciolosis.

Liver fluke (Fasciola hepatica) co-infection with bovine tuberculosis in cattle: A prospective herd-level assessment of herd bTB risk in dairy enterprises

Co-infection of tuberculosis (TB) and helminths is recognized as a significant problem in regions where such pathogens are endemic and chronic cases exist. Co-infection can modulate the immune system leading to interference with diagnostic tests, increased pathological impacts and pathogen persistence. However, research has found that such interactions between pathogens can be context and species specific. Recent studies have suggested that liver fluke, Fasciola hepatica, infection may impact on immunological responses and diagnostics for bovine tuberculosis (bTB; caused by Mycobacterium bovis) in cattle. Where evidence of such interaction exists, there would be an onus on policy makers to adjust eradication programs to minimize impacts. We assessed the association between herd-level bTB breakdown risk and seasonal variation in liver fluke exposure based on 5,753 bulk tank milk (BTM) samples from 1,494 dairy herds across Northern Ireland. BTM was tested by an IDEXX antibody specific enzyme-linked immunosorbent assay (ELISA) using the 'f2' antigen as a detection agent. The ELISA determined the result based on a sample to (known) positive ratio (S/P%) from which binary status and categories of exposure were derived. Associations were tested using multivariable random effects models. Models predicting bTB risk were not improved with the inclusion of liver fluke exposure levels. Variations in modelling liver fluke exposure (S/P%, binary, categories of exposure) and bTB risk (skin test breakdowns, post-mortem confirmed breakdowns, breakdown size and lag effects) also failed to support associations (neither positive nor negative) between the pathogens at herd-level. These results, along with previously published animal-level data from Northern Ireland, suggest that the nexus between bTB and F. hepatica may have small size effects at the population-level. However, our results also highlight the high prevalence of F. hepatica in cattle in our study population, and therefore we cannot fully discount the potential hypothesis of population-level depression of immune response to M. bovis due to co-infection.

Impact of Imperfect Disease Detection on the Identification of Risk Factors in Veterinary Epidemiology

Risk factors are key epidemiological concepts that are used to explain disease distributions. Identifying disease risk factors is generally done by comparing the characteristics of diseased and non-diseased populations. However, imperfect disease detectability generates disease observations that do not necessarily represent accurately the true disease situation. In this study, we conducted an extensive simulation exercise to emphasize the impact of imperfect disease detection on the outcomes of logistic models when case reports are aggregated at a larger scale (e.g., diseased animals aggregated at farm level). We used a probabilistic framework to simulate both the disease distribution in herds and imperfect detectability of the infected animals in these herds. These simulations show that, under logistic models, true herd-level risk factors are generally correctly identified but their associated odds ratio are heavily underestimated as soon as the sensitivity of the detection is less than one. If the detectability of infected animals is not only imperfect but also heterogeneous between herds, the variables associated with the detection heterogeneity are likely to be incorrectly identified as risk factors. This probability of type I error increases with increasing heterogeneity of the detectability, and with decreasing sensitivity. Finally, the simulations highlighted that, when count data is available (e.g., number of infected animals in herds), they should not be reduced to a presence/absence dataset at the herd level (e.g., presence or not of at least one infected animal) but rather modeled directly using zero-inflated count models which are shown to be much less sensitive to imperfect detectability issues. In light of these simulations, we revisited the analysis of the French bovine abortion surveillance data, which has already been shown to be characterized by imperfect and heterogeneous abortion detectability. As expected, we found substantial differences between the quantitative outputs of the logistic model and those of the zero-inflated Poisson model. We conclude by strongly recommending that efforts should be made to account for, or at the very least discuss, imperfect disease detectability when assessing associations between putative risk factors and observed disease distributions, and advocate the use of zero-inflated count models if count data is available.

Liver fluke (Fasciola hepatica) co-infection with bovine tuberculosis (bTB) in cattle: A retrospective animal-level assessment of bTB risk in dairy and beef cattle

Bovine tuberculosis (bTB), caused by Mycobacterium bovis, remains a persistent problem for cattle industries in endemic countries. The frequency, quality, and performance of tests, and the presence of wildlife reservoirs, have been identified as impediments to eradication. Recently, exposure to helminth infection (Fasciola hepatica) has been associated negatively with the disclosure of bTB. Here, for the first time, we assess impact of concurrent infections of Fasciola hepatica and the disclosure of bTB at the animal-level using large surveillance datasets. We utilized a dataset of 138,566 animal records from an abattoir from Northern Ireland (2011-2013). The presence of F. hepatica infection was assessed from macroscopic tissue inspection at abattoir. Multivariable models were developed to assess co-infection associations with bTB status based on: Single Intradermal Comparative Tuberculin Test (SICTT), lesion, bacteriological confirmation, including either all animals, or only skin-test negative animals (lesions at routine slaughter; LRS; confirmed nonreactors at routine slaughter; cNRs) or positive (reactors) animals alone, respectively. The relationship between skin tuberculin reaction sizes and fluke status was also explored for a subset of animals with field recordings (n = 24,680). Controlling for known risk factors (e.g., climatic, herd, and individual level characteristics), we did not find significant associations between the SICTT (standard or severe interpretation), lesion, nor confirmation status of animals and their liver fluke status. The only exception was a negative association between liver fluke positivity, and LRS or cNRs, respectively; though effect-sizes were small (e.g., LRS Odds-Ratio: 0.87; 95% CI: 0.76-1.00). There was limited evidence of a relationship between tuberculin reaction sizes during SICTT testing and liver fluke infection status. These data do not support the contention that the detection of bTB using skin-tests or reactor postmortem follow-up may be compromised by co-infection at a population level, but the relationship with lesion formation (pathogenesis) may indicate an impact for postmortem surveillance.

Development and validation of a protocol to identify and recruit participants into a large scale study on liver fluke in cattle

Background

Liver fluke infection caused by the parasite Fasciola hepatica is a major cause of production losses to the cattle industry in the UK. To investigate farm-level risk factors for fluke infection, a randomised method to recruit an appropriate number of herds from a defined geographical area into the study was required. The approach and hurdles that were encountered in designing and implementing this study are described. The county of Shropshire, England, was selected for the study because of the variation between farms in exposure to fluke infection observed in an earlier study.

Results

From a sampling list of 569 holdings in Shropshire randomly drawn from the RADAR cattle population dataset, 396 (69.6%) holdings were successfully contacted by telephone and asked if they would be interested in taking part in the study. Of 296 farmers who agreed to receive information packs by post, 195 (65.9%) agreed to take part in the study. Over the period October 2014 – April 2015 visits were made to 100 dairy and 95 non-dairy herds. During the farm visits 40 faecal samples +/− bulk-tank milk samples were collected and a questionnaire administered. Composite faecal samples were analysed for the presence of F. hepatica eggs by sedimentation and bulk tank milk samples were tested with an antibody ELISA for F. hepatica. Forty-five (49%) of non-dairy herds were positive for liver fluke infection as determined by the finding of one or more fluke eggs, while 36 (36%) dairy herds had fluke positive faecal samples and 41 (41%) dairy herds were positive for F. hepatica antibody. Eighty-seven (45.8%) farmers said that they monitored their cattle for liver fluke infection and 118 (62.1%) reported that they used flukicide drugs in their cattle.

Conclusions

Using a protocol of contacting farmers directly by telephone and subsequently sending information by post, 79% of the target sample size was successfully recruited into the study. A dataset of farm-specific information on possible risk factors for liver fluke infection and corresponding liver-fluke infection status was generated for the development of statistical models to identify risk factors for liver fluke infection at the farm-level.

Seasonal variation of Fasciola hepatica antibodies in dairy herds in Northern Ireland measured by bulk tank milk ELISA

Bovine fasciolosis, caused by the infection of the trematode parasite Fasciola hepatica, remains a problem in dairy herds causing significant production losses. In this study, bulk milk tank samples were utilised to generate a comprehensive survey of the variation in liver fluke exposure over the four seasons of 2016 in Northern Ireland (NI). Samples were tested using an antibody ELISA test; within-herd prevalence levels were categorised relative to sample-to-positive ratio (S/P%). Overall, 1494 herds (~ 50% of all active dairy farms in NI) were sampled. In total, 5750 samples were tested with 91% of herds having a sample result for each season. The proportion of herds with evidence of liver fluke exposure was very high across the year, with 93.03% of all bulk milk samples having some indication of liver fluke antibody presence. A high proportion of samples (2187/5750; 38.03%) fell within the highest infection class (indicating high within-herd prevalence). There was significant seasonal variation in the mean S/P%. A multivariable random effect ordinal logit model suggested that the greatest probability of being in a higher infection class was in winter, whilst the lowest was recorded during summer. There was a significant negative association between increasing herd liver fluke infection class and herd size. Furthermore, there was significant variation in infection levels across regions of Northern Ireland, with higher infection levels in northern administrative areas. This study demonstrates the very high liver fluke exposure in this region of Europe, and that risk is not equally distributed spatially or across seasons in dairy herds.

Performativity and a microbe: Exploring Mycobacterium bovis and the political ecologies of bovine tuberculosis

Mycobacterium bovis, the bacterium responsible for causing bovine tuberculosis (bTB) in cattle, displays what I call ‘microbial performativity’. Like many other lively disease-causing microorganisms, it has an agency which is difficult to contain, and there is a need for fresh thinking on the challenges of dealing with this slippery and indeterminate microbe. As a practising veterinary scientist who side-stepped mid-career into a parallel training in the social sciences to view bTB from an alternative perspective, I create an interdisciplinary coming-together where veterinary science converges with a political ecology of (animal) health influenced by science and technology studies (STS) and social science and humanities scholarship on performativity. This suitably hybridized nexus creates a place to consider the ecologies of a pathogen which could be considered as life out of control. I consider what this means for efforts to eradicate this disease through combining understandings from the published scientific literature with qualitative interview-based fieldwork with farmers, veterinarians and others involved in the statutory bTB eradication programme in a high incidence region of the UK. This study demonstrates the value of life scientists turning to the social sciences to re-view their familiar professional habitus—challenging assumptions, and offering alternative perspectives on complex problems.

Bovine Tuberculosis in Britain and Ireland - A Perfect Storm? the Confluence of Potential Ecological and Epidemiological Impediments to Controlling a Chronic Infectious Disease

Successful eradication schemes for bovine tuberculosis (bTB) have been implemented in a number of European and other countries over the last 50 years. However, the islands of Britain and Ireland remain a significant aberration to this trend, with the recent exception of Scotland. Why have eradication schemes failed within these countries, while apparently similar programs have been successful elsewhere? While significant socio-economic and political factors have been discussed elsewhere as key determinants of disease eradication, here we review some of the potential ecological and epidemiological constraints that are present in these islands relative to other parts of Europe. We argue that the convergence of these potential factors may interact additively to diminish the potential of the present control programs to achieve eradication. Issues identified include heterogeneity of diagnostic testing approaches, the presence of an abundant wildlife reservoir of infection and the challenge of sustainably managing this risk effectively; the nature, size, density and network structure of cattle farming; potential effects of Mycobacterium bovis strain heterogeneity on disease transmission dynamics; possible impacts of concurrent endemic infections on the disclosure of truly infected animals; climatological differences and change coupled with environmental contamination. We further argue that control and eradication of this complex disease may benefit from an ecosystem level approach to management. We hope that this perspective can stimulate a new conversation about the many factors potentially impacting bTB eradication schemes in Britain and Ireland and possibly stimulate new research in the areas identified.

Genetic correlations between endo-parasite phenotypes and economically important traits in dairy and beef cattle

Parasitic diseases have economic consequences in cattle production systems. Although breeding for parasite resistance can complement current control practices to reduce the prevalence globally, there is little knowledge of the implications of such a strategy on other performance traits. Records on individual animal antibody responses to Fasciola hepatica, Ostertagia ostertagi, and Neospora caninum were available from cows in 68 dairy herds (study herds); national abattoir data on F. hepatica-damaged livers were also available from dairy and beef cattle. After data edits, 9,271 dairy cows remained in the study herd dataset, whereas 19,542 dairy cows and 68,048 young dairy and beef animals had a record for the presence or absence of F. hepatica-damaged liver in the national dataset. Milk, reproductive, and carcass phenotypes were also available for a proportion of these animals as well as their contemporaries. Linear mixed models were used to estimate variance components of antibody responses to the three parasites; covariance components were estimated between the parasite phenotypes and economically important traits. Heritability of antibody responses to the different parasites, when treated as a continuous trait, ranged from 0.07 (O. ostertagi) to 0.13 (F. hepatica), whereas the coefficient of genetic variation ranged from 4% (O. ostertagi) to 20% (F. hepatica). The antibody response to N. caninum was genetically correlated with the antibody response to both F. hepatica (-0.29) and O. ostertagi (-0.67); a moderately positive genetic correlation existed between the antibody response to F. hepatica and O. ostertagi (0.66). Genetic correlations between the parasite phenotypes and the milk production traits were all close to zero (-0.14 to 0.10), as were the genetic correlations between F. hepatica-damaged livers and the carcass traits of carcass weight, conformation, and fat score evaluated in cows and young animals (0.00 to 0.16). The genetic correlation between F. hepatica-damaged livers in cows and milk somatic cell score was 0.32 (SE = 0.20). Antibody responses to F. hepatica and O. ostertagi had favorable genetic correlations with fertility traits, but conversely, antibody response to N. caninum and F. hepatica-damaged livers were unfavorably genetically correlated with fertility. This study provides the necessary information to undertake national multitrait genetic evaluations for parasite phenotypes.

Modelling the variation in skin-test tuberculin reactions, post-mortem lesion counts and case pathology in tuberculosis-exposed cattle: Effects of animal characteristics, histories and co-infection

Correctly identifying bovine tuberculosis (bTB) in cattle remains a significant problem in endemic countries. We hypothesized that animal characteristics (sex, age, breed), histories (herd effects, testing, movement) and potential exposure to other pathogens (co-infection; BVDV, liver fluke and Mycobacterium avium reactors) could significantly impact the immune responsiveness detected at skin testing and the variation in post-mortem pathology (confirmation) in bTB-exposed cattle. Three model suites were developed using a retrospective observational data set of 5,698 cattle culled during herd breakdowns in Northern Ireland. A linear regression model suggested that antemortem tuberculin reaction size (difference in purified protein derivative avium [PPDa] and bovine [PPDb] reactions) was significantly positively associated with post-mortem maximum lesion size and the number of lesions found. This indicated that reaction size could be considered a predictor of both the extent (number of lesions/tissues) and the pathological progression of infection (maximum lesion size). Tuberculin reaction size was related to age class, and younger animals (<2.85 years) displayed larger reaction sizes than older animals. Tuberculin reaction size was also associated with breed and animal movement and increased with the time between the penultimate and disclosing tests. A negative binomial random-effects model indicated a significant increase in lesion counts for animals with M. avium reactions (PPDb-PPDa < 0) relative to non-reactors (PPDb-PPDa = 0). Lesion counts were significantly increased in animals with previous positive severe interpretation skin-test results. Animals with increased movement histories, young animals and non-dairy breed animals also had significantly increased lesion counts. Animals from herds that had BVDV-positive cattle had significantly lower lesion counts than animals from herds without evidence of BVDV infection. Restricting the data set to only animals with a bTB visible lesion at slaughter (n = 2471), an ordinal regression model indicated that liver fluke-infected animals disclosed smaller lesions, relative to liver fluke-negative animals, and larger lesions were disclosed in animals with increased movement histories.

Bovine tuberculosis visible lesions in cattle culled during herd breakdowns: the effects of individual characteristics, trade movement and co-infection

BACKGROUND

Bovine tuberculosis (bTB), caused by Mycobacterium bovis, remains a significant problem for livestock industries in many countries worldwide including Northern Ireland, where a test and slaughter regime has utilised the Single Intradermal Comparative Cervical Tuberculin (SICCT) test since 1959. We investigated the variation in post-mortem confirmation based on bTB visible lesion (VL) presence during herd breakdowns using two model suites. We investigated animal-level characteristics, while controlling for herd-level factors and clustering. We were interested in potential impacts of concurrent infection, and therefore we assessed whether animals with evidence of liver fluke infection (Fasciola hepatica; post-mortem inspection), M. avium reactors (animals with negative M. bovis-avium (b-a) tuberculin reactions) or Bovine Viral Diarrhoea Virus (BVDV; RT-PCR tested) were associated with bTB confirmation.

RESULTS

The dataset included 6242 animals removed during the 14 month study period (2013-2015). bTB-VL presence was significantly increased in animals with greater b-a reaction size at the disclosing SICCT test (e.g. b-a = 5-9 mm vs. b-a = 0 mm, adjusted Odds ratio (aOR): 14.57; p < 0.001). M. avium reactor animals (b-a < 0) were also significantly more likely to disclose VL than non-reactor animals (b-a = 0; aOR: 2.29; p = 0.023). Animals had a greater probability of exhibiting lesions with the increasing number of herds it had resided within (movement; log-herds: aOR: 2.27-2.42; p < 0.001), if it had an inconclusive penultimate test result (aOR: 2.84-3.89; p < 0.001), and with increasing time between tests (log-time; aOR: 1.23; p = 0.003). Animals were less likely to have VL if they were a dairy breed (aOR: 0.79; p = 0.015) or in an older age-class (e.g. age-quartile 2 vs. 4; aOR: 0.65; p < 0.001). Liver fluke or BVDV variables were not retained in either multivariable model as they were non-significantly associated with bTB-VL status (p > 0.1).

CONCLUSIONS

Our results suggest that neither co-infection of liver fluke nor BVDV had a significant effect on the presence of VLs in this high-risk cohort. M. avium tuberculin reactors had a significantly increased risk of disclosing with a bTB lesion, which could be related to the impact of co-infection with M. avium subsp. paratuberculosis (MAP) affecting the performance of the SICCT however further research in this area is required. Movements, test history, breed and age were important factors influencing confirmation in high-risk animals.

Farm-level risk factors for Fasciola hepatica infection in Danish dairy cattle as evaluated by two diagnostic methods

Background

The prevalence of bovine fasciolosis in Denmark is increasing but appropriate guidelines for control are currently lacking. In order to help develop a control strategy for liver fluke, a risk factor study of farm management factors was conducted and the utility of bulk tank milk (BTM ELISA) as a tool for diagnosis in Danish dairy cattle farms was assessed.

Methods

This case-control study aimed to identify farm-level risk factors for fasciolosis in Danish dairy farms (> 50 animals slaughtered in 2013) using two diagnostic methods: recordings of liver condemnation at slaughter, and farm-level Fasciola hepatica antibody levels in BTM. A case farm was defined as having a minimum of 3 incidents of liver condemnation due to liver fluke at slaughter (in any age group) during 2013, and control farms were located within 10 km of at least one case farm and had no history of liver condemnation due to liver fluke during 2011–2013. The selected farmers were interviewed over telephone about grazing and control practices, and BTM from these farms was collected and analysed by ELISA in 2014. The final complete dataset consisting of 131 case and 63 control farms was analysed using logistic regression.

Results

Heifers grazing on wet pastures, dry cows grazing on wet pastures, herd size, breed and concurrent beef cattle production were identified as risk factors associated with being classified as a case farm. With the categorised BTM ELISA result as the response variable, heifers grazing on wet pastures, dry cows grazing on wet pastures, and purchase of cows were identified as risk factors. Within the case and control groups, 74.8 and 12.7% of farms were positive for fasciolosis on BTM ELISA, respectively. The differences are likely to be related to the detection limit of the farm-level prevalence by the BTM ELISA test, time span between slaughter data and BTM, and the relatively low sensitivity of liver inspection at slaughter.

Conclusions

Control of bovine fasciolosis in Denmark should target heifers and dry cows through grazing management and appropriate anthelmintic treatment, and BTM ELISA can be a useful diagnostic tool for fasciolosis in Danish dairy farms.

Electronic supplementary material

The online version of this article (10.1186/s13071-017-2504-y) contains supplementary material, which is available to authorized users.

Assessment of concurrent infection with bovine viral diarrhoea virus (BVDV) and Mycobacterium bovis: A herd-level risk factor analysis from Northern Ireland

Bovine viral diarrhoea virus (BVDV) is a significant pathogen of cattle, leading to severe economic and animal-welfare impacts. Furthermore, the pathogen has been associated with impacting the progression or spread of other pathogens (e.g. Mycobacterium bovis, the causative agent of bovine tuberculosis (bTB)). During this study we investigated (i) risk factors for BVDV at a herd-level and (ii) whether there was any association between BVDV and herd-level bTB risk. The data for this study were gathered from a voluntary BVDV control programme in Northern Ireland (2013-2015) based on the identification of virus positive animals through tissue tag testing of calves. We assigned a herd-level BVDV status to 2827 participating herds, where a herd was assumed "infected" if one or more animals tested positive for BVDV. Two model suites were developed. Firstly, we assessed risk factors for BVDV herd status using multivariable logit random-effects modelling, aggregating to the calendar year level (2013-2015; n=4828; model 1). Secondly, we aggregated data across the three years of the study to give an overall status for the whole study period (n=2827; logistic model 2). Risk factors included year, herd-type, herd size, number of births, inward trade moves, calf mortality, and region. Furthermore, the herd-level bovine tuberculosis status (based on the single intradermal comparative cervical tuberculin (SICCT) test outcomes, or confirmation at post-mortem), or the size of bTB breakdowns (number of SICCT test positive animals), of herds was also investigated to assess whether there was an association (co-infection) with herd BVDV status. The final models suggested that BVDV herd status was positively associated with increased levels of calf mortality, herd size, number of births, the number of BVDV tests undertaken and the number of animals introduced to the herd. There was a significant univariable positive association between BVDV status, and SICCT breakdown risk, breakdown size and confirmed bTB status in model 2. However, there was no evidence of significant associations between bTB status (using SICTT status, confirmed status or herd breakdown size) and BVDV status in final multivariable models when controlling for other significant confounders. These results provide information for action for the future control and eradication of BVDV in Northern Ireland, though these data provide little support for the hypothesised association between BVDV and bTB status at herd-level. Further animal-level analyses are necessary to investigate whether there is support for a BVD-bTB co-infection association, including the impact of co-infection on the severity of infection.

A reducing trend of fasciolosis in slaughtered animals based on abattoir data in South of Iran

AIM

Fascioliasis is a zoonosis infection caused by the liver trematodes (Fasciola spp.) which have been considered to be an important disease in livestock. After several large outbreaks, fascioliasis remains one of the serious health concerns of Iran. This study was conducted to evaluate the prevalence and possible trends of fascioliasis in slaughtered animals in South of Iran based on abattoir data during a period of 5 years.

MATERIALS AND METHODS

The daily records for cattle, sheep, and goats slaughtered in the abattoir were extracted from the archived documents of the recent 5 years (2011-2015) and used as the source of data. The collected data were statistically analyzed for finding any probable correlation between the various factors associated with fasciolosis.

RESULTS

Our results showed that 3.44% of all slaughtered animals during 2011-2015 were infected with Fasciola spp. The mean prevalence of fasciolosis for cattle, sheep, and goat was 11.15%, 5.22%, and 2.15%, respectively. In addition, the highest infection rate was in winter (4.02%), and the lowest were entered in summer (2.86%).

CONCLUSION

Our findings showed a reducing trend during the 5 years. Improving the animal husbandry and increasing the awareness through fasciolosis may be a logical explanation for this trend. Since there have been suggested numerous factors associated with the epidemiology of fasciolosis, further studies seem essential for better clarifying the various aspects of fasciolosis in areas.

Pig Abattoir Inspection Data: Can It Be Used for Surveillance Purposes?

Statutory recording of carcass lesions at the abattoir may have significant potential as a resource for surveillance of livestock populations. Food Standards Agency (FSA) data in Great Britain are not currently used for surveillance purposes. There are concerns that the sensitivity of detection, combined with other issues, may make the outputs unreliable. In this study we postulate that FSA data could be used for surveillance purposes. To test this we compared FSA data with BPHS (a targeted surveillance system of slaughtered pigs) and laboratory diagnostic scanning surveillance (FarmFile) data, from mid-2008 to mid-2012, for respiratory conditions and tail bite lesions in pigs at population level. We also evaluated the agreement/correlation at batch level between FSA and BPHS inspections in four field trials during 2013. Temporal trends and regional differences at population level were described and compared using logistic regression models. Population temporal analysis showed an increase in respiratory disease in all datasets but with regional differences. For tail bite, the temporal trend and monthly patterns were completely different between the datasets. The field trials were run in three abattoirs and included 322 batches. Pearson’s correlation and Cohen’s kappa tests were used to assess correlation/agreement between inspections systems. It was moderate to strong for high prevalence conditions but slight for low prevalence conditions. We conclude that there is potential to use FSA data as a component of a surveillance system to monitor temporal trends and regional differences of chosen indicators at population level. At producer level and for low prevalence conditions it needs further improvement. Overall a number of issues still need to be addressed in order to provide the pig industry with the confidence to base their decisions on these FSA inspection data. Similar conclusions, at national level, may apply to other livestock sectors but require further evaluation of the inspection and data collection processes.