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.     

Molecular epidemiology of Mycobacterium tuberculosis complex strains isolated from livestock and wild animals in Italy suggests the need for a different eradication strategy for bovine tuberculosis

Bovine tuberculosis (bTB ) is an important zoonosis, which has been re‐emerging in different ecological scenarios. In Sicily, Italy, from 2004 to 2014, an anatomopathological survey for tuberculosis‐like lesions both in farmed and wild animals was performed. The isolates were genotyped using spoligotyping and Mycobacterial Interspersed Repetitive Units‐Variable Number of Tandem Repeats (MIRU ‐VNTR ) techniques. High prevalence of lesions was observed for cattle (4%), pigs (4.9%) and wild boars (6.8%), and a total of 625 Mycobacterium bovis isolates were identified. Genotyping analysis showed the presence of 37 different spoligotypes including fifteen spoligotypes not present in other Italian regions and 266 MIRU ‐VNTR profiles. Spoligotype SB 0120 exhibited the highest prevalence in cattle (50%) and pigs (56%) and the highest genetic variety with 126 different MIRU ‐VNTR profiles. The isolation of M. bovis in a farmer underlines the importance of M. bovis identification during the human TB diagnostic processes. This study supported the use of the genotyping analysis as a valuable tool for the evaluation of the epidemiological role of pigs and other domestic reservoirs such as goats and the role of wildlife in the maintenance of bTB infection.     

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 of a Gene Expression Assay for the Diagnosis of Mycobacterium bovis Infection in African Lions (Panthera leo)

Mycobacterium bovis infection, the cause of bovine tuberculosis (BTB), is endemic in wildlife in the Kruger National Park (KNP), South Africa. In lions, a high infection prevalence and BTB mortalities have been documented in the KNP; however, the ecological consequences of this disease are currently unknown. Sensitive assays for the detection of this infection in this species are therefore required. Blood from M. bovis‐exposed, M. bovis‐unexposed, M. tuberculosis‐exposed and M. bovis‐infected lions was incubated in QuantiFERON^®‐TB Gold (QFT) tubes containing either saline or ESAT‐6/CFP‐10 peptides. Using qPCR, selected reference genes were evaluated for expression stability in these samples and selected target genes were evaluated as markers of antigen‐dependent immune activation. The abundance of monokine induced by gamma interferon (MIG/CXCL9) mRNA, measured in relation to that of YWHAZ, was used as a marker of ESAT‐6/CFP‐10 sensitization. The gene expression assay results were compared between lion groups, and lenient and stringent diagnostic cut‐off values were calculated. This CXCL9 gene expression assay combines a highly specific stimulation platform with a sensitive diagnostic marker that allows for discrimination between M. bovis‐infected and M. bovis‐uninfected lions.     

Seroprevalence of Rift valley fever in South African domestic and wild suids (1999–2016)

Rift valley fever (RVF) is a vector‐borne viral disease of domestic ruminants, camels and man, characterized by widespread abortions and neonatal deaths in animals, and flu‐like symptoms, which can progress to hepatitis and encephalitis in humans. The disease is endemic in Africa, Saudi Arabia and Yemen, and outbreaks occur after periods of high rainfall, or in environments supporting the proliferation of RVF virus (RVFV)‐infected mosquito vectors. The domestic and wild animal maintenance hosts of RVFV, which may serve as sources of virus during inter‐epidemic periods (IEPs) and contribute to occurrence of sporadic outbreaks, remain unknown, although reports indicate that the African buffalo (Syncerus caffer) may play a role. Due to the close proximity of the habitats of domestic pigs and warthogs to those of known domestic and wild ruminant RVFV maintenance hosts respectively, our study investigated their possible role in the epidemiology of RVF in South Africa by evaluating RVFV exposure and seroconversion in suids. A total of 107 warthog and 3,984 domestic pig sera from 2 and all 9 provinces of South Africa, respectively, were screened for presence of RVFV neutralizing antibodies using the virus neutralization test (VNT). Sero‐positivity rates of 1.87% (95% CI: 0.01%–6.9%) and 0.68% (95% CI: 0.49%–1.04%) were observed for warthogs and domestic pigs, respectively, but true prevalence rates, taking test sensitivity and specificity into account, were lower for both groups. There was a strong association between the results of the two groups (χ² = 0.75, p = .38), and differences in prevalence between the epidemic and IEPs were non‐significant for all suid samples tested (p > .05). This study, which provides the first evidence of probable exposure and infection of South African domestic pigs and warthogs to RVFV, indicates that further investigations are warranted, to fully clarify the role of suids in the epidemiology of RVF.     

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 [PPD a ] and bovine [PPD b ] 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 (PPD b− PPD a <  0) relative to non‐reactors (PPD b− PPD a =  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.     

Isolation and Potential for Transmission of Mycobacterium bovis at Human–livestock–wildlife Interface of the Serengeti Ecosystem,Northern Tanzania

Mycobacterium bovis, the causative agent of bovine tuberculosis (bTB), is a multihost pathogen of public health and veterinary importance. We characterized the M. bovis isolated at the human–livestock–wildlife interface of the Serengeti ecosystem to determine the epidemiology and risk of cross‐species transmission between interacting hosts species. DNA was extracted from mycobacterial cultures obtained from sputum samples of 472 tuberculosis (TB) suspected patients and tissue samples from 606 livestock and wild animal species. M. bovis isolates were characterized using spoligotyping and Mycobacterial Interspersed Repetitive Units‐Variable Tandem Repeats (MIRU‐VNTR) on 24 loci. Only 5 M. bovis were isolated from the cultured samples. Spoligotyping results revealed that three M. bovis isolates from two buffaloes (Syncerus caffer) and 1 African civet (Civettictis civetta) belonged to SB0133 spoligotype. The two novel strains (AR1 and AR2) assigned as spoligotype SB2290 and SB2289, respectively, were identified from indigenous cattle (Bos indicus). No M. bovis was detected from patients with clinical signs consistent with TB. Of the 606 animal tissue specimens and sputa of 472 TB‐suspected patients 43 (7.09%) and 12 (2.9%), respectively, yielded non‐tuberculous mycobacteria (NTM), of which 20 isolates were M. intracellulare. No M. avium was identified. M. bovis isolates from wildlife had 45.2% and 96.8% spoligotype pattern agreement with AR1 and AR2 strains, respectively. This finding indicates that bTB infections in wild animals and cattle were epidemiologically related. Of the 24 MIRU‐VNTR loci, QUB 11b showed the highest discrimination among the M. bovis strains. The novel strains obtained in this study have not been previously reported in the area, but no clear evidence for recent cross‐species transmission of M. bovis was found between human, livestock and wild animals.     

Tuberculosis in Rhinoceros: An Underrecognized Threat?

Historical evidence of tuberculosis (TB) affecting primarily captive rhinoceroses dates back almost two centuries. Although the causative Mycobacterium tuberculosis complex (MTC) species has not been determined in many cases, especially for those that occurred before bacterial culture techniques were available, the spectrum of documented reports illustrates the importance of TB as cause of morbidity and mortality in different rhinoceros species across continents. In more recent years, sporadic suspected or confirmed cases of TB caused by Mycobacterium bovis (M. bovis) have been reported in semi‐free or free‐ranging rhinoceroses in South Africa. However, the true risk TB may pose to the health and conservation of rhinoceros populations in the country's large conservation areas where M. bovis is endemic, which is unknown. Underlying the current knowledge gap is the lack of diagnostic tools available to detect infection in living animals. As documented in other wildlife species, TB could establish itself in a rhinoceros population but remain unrecognized for decades with detrimental implications for wildlife conservation at large and should such animals be moved to uninfected areas or facilities. This paper reviews the current state of knowledge regarding TB in rhinoceros including critical gaps that need to be addressed to effectively assess the threat that this disease may present to rhinoceros.     

First detection of Mycobacterium bovis infection in Giraffe (Giraffa camelopardalis) in the Greater Kruger National Park Complex: Role and implications

Bovine tuberculosis (bovine TB) caused by Mycobacterium bovis has become endemic in some wildlife populations in South Africa. The disease has been reported in 21 wildlife species in the country. In this study, we report M. bovis infection in two female giraffes (Giraffa camelopardalis) from two different nature reserves within the Greater Kruger National Park Complex (GKNPC). Mycobacterium bovis was isolated from tissue lesions consistent with macroscopic appearance of tuberculosis (TB) and confirmed by polymerase chain reactions (PCRs), targeting the RD4 region of difference on the genome of the isolates. Spoligotyping and variable number of tandem repeat (VNTR) typing revealed infection of one giraffe with a strain (SB0294) previously not detected in South Africa, while a resident M. bovis strain (SB0121) was detected from the other giraffe. Our work is first to report M. bovis infection in free‐ranging giraffes in South Africa. We have further demonstrated the existence of at least three genetically unrelated strains currently infecting wildlife species within the GKNPC. This finding suggests that the epidemiological situation of M. bovis within the GKNPC is not only driven by internal sources from its established endemic presence, but can be additionally fuelled by strains introduced from external sources. It further emphasizes that regular wildlife disease surveillance is an essential prerequisite for the timely identification of new pathogens or strains in ecospheres of high conservation value.     

Tuberculosis in Southern Brazilian wild boars (Sus scrofa): First epidemiological findings

Bovine tuberculosis (bTB ) is a zoonosis caused mainly by Mycobacterium bovis that affects domestic and wild animals. In Brazil, there are no epidemiological studies on tuberculosis in wild animal populations and their possible role in the disease maintenance in cattle herds; thus, the aim of this study was to evaluate the occurrence of tuberculosis in wild boars in Rio Grande do Sul, southern Brazil. Tissue samples of animals hunted under government consent were submitted to histopathology and M. bovis polymerase chain reaction (PCR ) as screening tests; the positive samples were subsequently submitted to bacterial isolation, the gold standard diagnosis. Eighty animals were evaluated, of which 27.9% and 31.3% showed histopathological changes and M. bovis genome presence, respectively. Moreover, 23.8% of the animals had at least one organ with isolates classified as Mycobacterium tuberculosis complex (MTC ). Three hunting points were risk factors for positive results on screening tests. This study shows the occurrence of tuberculosis in a wild boars’ population, and raise the possibility of these animals to play a role as disease reservoirs in southern Brazil. These results may help to improve the Brazilian tuberculosis control programme, as well as elucidate the circulation of mycobacteria in this country.     

Evaluation of the Interferon‐γ Assay on Blood Collected at Exsanguination of Cattle Under Field Conditions for Surveillance of Bovine Tuberculosis

Development of point of concentration (POC) surveillance strategies for bovine tuberculosis (bTB) would facilitate global efforts to eradicate bTB. The interferon‐gamma (IFNγ) assay can detect IFNγ responses to Mycobacterium bovis in blood collected at commencement of exsanguination (COE) of experimentally challenged cattle but has not been evaluated under field conditions. The current study was aimed at determining (i) whether blood collected at COE of cattle at slaughter, under field conditions, is practical to obtain and useful for identifying cattle as IFNγ positive for bTB, (ii) whether the results of the IFNγ assay obtained at COE reliably compare with results obtained from live animals in the field, and (iii) whether the identified animal(s) originated from bTB‐infected or bTB‐exposed herds. Cattle from three risk groups were used: the highest risk group consisted of 49 cattle from 3 bTB‐infected herds; the medium risk group consisted of 24 cattle from a potentially exposed herd; and the lowest risk group consisted of 60 cattle from herds with no known history of bTB exposure. The IFNγ assay was performed on blood collected both before stunning and at COE of cattle at slaughter. An enhanced slaughter inspection for gross lesions consistent with bTB was performed on all cattle. In addition, lymph nodes were cultured for M. bovis for cattle that tested positive for bTB via the IFNγ assay and for most cattle that tested negative for bTB. Cattle, both with and without lesions consistent with bTB, were identified as positive for bTB by the IFNγ assay using blood collected at COE, but none of the positive cattle originated from the lowest risk group. The current study demonstrates that blood collected at COE of cattle is both a practical and moderately reliable sample for accessing bTB infection using the IFNγ assay.     

Factors that Influence Mycobacterium bovis Infection in Red Deer and Wild Boar in an Epidemiological Risk Area for Tuberculosis of Game Species in Portugal

Bovine tuberculosis (bTB) is a worldwide zoonotic disease of domestic and wild animals. Eradication has proved elusive in those countries with intensive national programmes but with ongoing transmission between wildlife and cattle. In Portugal, a high‐risk area for bTB was defined and specific measures implemented to assess and minimize the risk from wildlife. Data from the 2011 to 2014 hunting seasons for red deer (Cervus elaphus) and wild boar (Sus scrofa) were analysed with bovine demographic and bTB information to assess factors that determined the occurrence and distribution of bTB in both species. The likelihood of bTB‐like lesions in wild boar was positively associated with density of red deer, wild boar and cattle, while for red deer, only their density and age were significant factors. The likelihood of Mycobacterium bovis isolation in wild boar was associated with density of cattle and red deer and also with the anatomical location of lesions, while for red deer, none of the variables tested were statistically significant. Our results suggest that, in the study area, the role of red deer and wild boar may be different from the one previously suggested by other authors for the Iberian Peninsula, as red deer may be the driving force behind M. bovis transmission to wild boar. These findings may assist the official services and game managing bodies for the management of hunting zones, what could also impact the success of the bTB eradication programme.     

Spatiotemporal monitoring of selected pathogens in Iberian ibex (Capra pyrenaica)

An epidemiological surveillance programme was carried out to assess exposure and spatiotemporal patterns of selected pathogens (Brucella spp., Mycobacterium avium subsp. paratuberculosis (MAP), Mycoplasma agalactiae, Pestivirus and bluetongue virus (BTV)) in Iberian ibex (Capra pyrenaica) from Andalusia (southern Spain), the region with the largest population of this species. A total of 602 animals in five distribution areas were sampled during 2010–2012 (P1) and 2013–2015 (P2). The Rose Bengal test (RBT) and complement fixation test (CFT) were used in parallel to detect anti‐Brucella spp. antibodies. Commercial ELISAs were used to test for antibodies against the other selected pathogens. Sera positive for BTV and Pestivirus by ELISA were tested by serum neutralization test (SNT) to identify circulating serotypes/genotypes. The overall seroprevalences were as follows: 0.4% for Brucella spp. (2/549; CI 95%: 0.1–1.3) (14/555 positive by RBT; 2/564 by CFT), 0.5% for MAP (3/564; CI 95%: 0.1–1.5), 5.7% for M. agalactiae (30/529; CI 95%: 3.9–8.0), 11.1% for Pestivirus (58/525; CI 95%: 8.5–14.1) and 3.3% for BTV (18/538; CI 95%: 2.0–5.2). Significantly higher seropositivity to both M. agalactiae and BTV was observed in P1 compared with P2. Spatiotemporal clusters of high seroprevalence were also found for M. agalactiae in four of the five sampling areas in 2010, and for BTV in one of five areas in 2012. Specific antibodies against BTV‐4, BDV‐4 and BVDV‐1 were confirmed by SNT. Our results indicate that the Iberian ibex may be considered spillover hosts of Brucella spp. and MAP rather than true reservoirs. The prevalence of antibodies against M. agalactiae and BTV suggests spatiotemporal variation in the circulation of these pathogens, while Pestivirus has a moderately endemic circulation in Iberian ibex populations. Our study highlights the importance of long‐term surveillance for a better understanding of the spatiotemporal distribution of shared infectious diseases and providing valuable information to improve control measures at the wildlife–livestock interface.     

Non‐tuberculous Mycobacteria in Wild Boar (Sus scrofa) from Southern Spain: Epidemiological,Clinical and Diagnostic Concerns

Non‐tuberculous mycobacteria (NTM) are widely distributed in the environment, particularly in wet soil, marshland, rivers or streams, but also are causative agents of a wide variety of infections in animals and humans. Little information is available regarding the NTM prevalence in wildlife and their effects or significance in the bovine tuberculosis (bTB) epidemiology and diagnosis. This research shows the most frequently NTM isolated in lymph nodes of wild boar (Sus scrofa) from southern Spain, relating the NTM presence with the individual characteristics, the management of animals and the possible misdiagnosis of Mycobacterium bovis in concurrent infections. A total of 219 NTM isolates were obtained from 1249 wild boar mandibular lymph nodes sampled between 2007 and 2011. All but 75 isolates were identified by the PCR‐restriction analysis‐hsp65, and a partial sequencing of the 16S rDNA was carried out to identify the rest of the isolates. Results showed that Mycobacterium chelonae was the most frequently isolated NTM specie (133 isolates, 60.7%), followed by Mycobacterium avium (24 isolates, 11%). No relation was found regarding sex, body condition and management, but M. chelonae was more frequently detected in adults, whereas M. avium was more prevalent in subadults. The high NTM prevalence observed in the studied wild boar populations could make difficult the bTB diagnostic.     

Comparative Pathology of the Natural infections by Mycobacterium bovis and by Mycobacterium caprae in Wild Boar (Sus scrofa)

The potential role of wild animals in the maintenance and spread of tuberculosis (TB) infection in domestic livestock is of particular importance in countries where eradication programs have substantially reduced the incidence of bovine tuberculosis but sporadic outbreaks still occur. Mycobacterium bovis is the agent mainly isolated in wildlife in Spain, but recently, infections by Mycobacterium caprae have increased substantially. In this study, we have analysed 43 mandibular lymph nodes samples containing TB‐like lesions from 43 hunted wild boar from Madrid and Extremadura (central and south‐western regions of Spain). After isolation, identification and typing of Mycobacterium tuberculosis complex isolates, we found that 23 mandibular lymph nodes involved M. caprae infections and 20 M. bovis. The lesions were compared for histopathology (different granuloma stage and number of multinucleated giant cells (MNGCs)), and acid‐fast bacilli (AFBs) were quantified in the Ziehl‐Neelsen‐stained slides. Granulomas produced by M. caprae showed more stage IV granulomas, more MNGCs and higher AFBs counts than those induced by M. bovis. In conclusion, lesions caused by M. caprae would be more prone to the excretion of bacilli, and infected animals result as a high‐risk source of infection for other animals.     

Persistence of Mycobacterium bovis bacillus Calmette–Guérin (BCG) Danish In White‐tailed Deer (Odocoileus virginianus) Vaccinated with a Lipid‐Formulated Oral Vaccine

Mycobacterium bovis, the causative agent of tuberculosis in animals, has a broad host range, including humans. Historically, public health concerns prompted programs to eradicate tuberculosis from cattle in many nations. Eradication efforts decreased the prevalence of bovine tuberculosis; nevertheless, some countries encountered significant obstacles, not least of which was a wildlife reservoir of M. bovis. Efforts to decrease the size of the affected wildlife populations have neither eliminated disease nor eliminated transmission to cattle. Consequently, the use of a vaccine for wildlife is being explored. The vaccine most studied is M. bovis BCG, an attenuated live vaccine, first developed 100 years ago. The most efficient and effective means of vaccinating wildlife will be an oral vaccine. White‐tailed deer in Michigan, USA, constitute a reservoir of M. bovis. White‐tailed deer are a popular game species, and as such, represent a food animal to many hunters. BCG persistence in deer tissues could result in human exposure to BCG. Although non‐pathogenic, BCG exposure could induce false‐positive skin test results, confounding the central component of public health surveillance for TB. The objective of the present study in white‐tailed deer was to evaluate persistence of lipid‐encapsulated BCG and a liquid suspension of BCG after oral administration at two different dosages. Vaccine was not recovered at any time after oral consumption of a bait containing a single dose (1 × 10⁸ CFU) of lipid‐encapsulated BCG. However, persistence was consistent in deer consuming 10 lipid‐encapsulated baits (1 × 10⁹ CFU), with BCG recovered from at least one deer at 1, 3, 6, 9 and 12 months after consumption. Persistence of up to 9 months was seen in deer vaccinated with orally with a liquid suspension. Persistence of BCG was limited to lymphoid tissue and never found in samples of muscle collected at each time point. Although the risk of exposure to hunters is low, BCG persistence should be considered prior to field use in white‐tailed deer.     

Identifying emerging trends in antimicrobial resistance using Salmonella surveillance data in poultry in Spain

Despite of controls and preventive measures implemented along the food chain, infection with non‐typhoidal Salmonella (NTS) remains one of the major causes of foodborne disease worldwide. Poultry is considered one of the major sources of NTS. This has led to the implementation of monitoring and control programmes in many countries (including Spain) to ensure that in poultry flocks infection is kept to a minimum and to allow the identification and monitoring of circulating NTS strains and their antimicrobial resistance (AMR) phenotypes. Here, we investigated the information from the monitoring programme for AMR in Salmonella from poultry in Spain in 2011–2017 to assess the diversity in phenotypic resistance and to evaluate the programme's ability to detect multi‐resistance patterns and emerging strains in the animal reservoir. Data on serotype and AMR to nine antimicrobials obtained from 3,047 NTS isolates from laying hens (n = 1,060), broiler (n = 765) and turkey (n = 1,222) recovered during controls performed by the official veterinary services and food business operators were analysed using univariate and multivariate methods in order to describe host and serotype‐specific profiles. Diversity and prevalence of phenotypic resistance to all but one of the antimicrobials (colistin) were higher in NTS from broiler and turkey compared with laying hen isolates. Certain combinations of serotype and AMR pattern (resistotype) were particularly linked with certain hosts (e.g. susceptible Enteritidis with laying hens, multi‐drug resistant (MDR) Derby in turkey, MDR Kentucky in turkey and broiler). The widespread presence of certain serotype‐resistotype combinations in certain hosts/years suggested the possible expansion of MDR strains in the animal reservoir. This study demonstrates the usefulness of the analysis of data from monitoring programmes at the isolate level to detect emerging threats and suggests aspects that should be subjected to further research to identify the forces driving the expansion/dominance of certain strains in the food chain.     

Occurrence and Diversity of Giardia duodenalis Assemblages in Livestock in the UK

Giardia duodenalis is a common intestinal parasite in humans and a wide range of livestock species. It is a genetically heterogeneous parasite that has been characterized in seven distinct genetic assemblages or cryptic species, and molecular markers can be used to differentiate both animal‐specific and potentially zoonotic genotypes. Little is known about G. duodenalis and the range of assemblages occurring in domestic livestock species in the UK. Here, we present data on the occurrence and molecular diversity of G. duodenalis detected in the faeces or large intestinal contents of cattle, sheep, pigs, goats and camelids from farms in the north‐west of England. Both healthy and clinically diseased animals were included in the survey. The presence of Giardia spp. and assemblages was determined by sequencing of the small‐subunit ribosomal RNA gene. The potential association of infection with various clinical and epidemiological parameters was studied in cattle using both univariate and multivariate analyses. Giardia spp. were detected in 127 (34.3%) of the 370 animals tested. G. duodenalis assemblage E was found to be predominant in cattle and sheep, followed by assemblage A. Mixed infections with assemblages A and E were also detected. Interestingly, some cattle, sheep and pigs were found to be infected with more unexpected assemblages (C, D, F). Pre‐weaned calves were more likely to test positive than adult animals, but no association between the occurrence of overt intestinal disease and G. duodenalis infection was detected. The common occurrence of assemblage A and the finding of unusual assemblages in atypical hosts suggest that in future, a multilocus analysis should be used to confirm the actual diversity of G. duodenalis in livestock and the presence of potentially zoonotic genotypes. These data also suggest that there is a need to re‐evaluate the clinical significance of G. duodenalis infection in livestock.     

Molecular Study of Dirofilaria immitis and Dirofilaria repens in Dogs from Tunisia

Dirofilaria immitis and Dirofilaria repens are mosquito‐borne nematodes which infect primarily dogs as their main definitive hosts. They cause cardiopulmonary (D. immitis) or cutaneous (D. repens) dirofilariasis in canids and other carnivores and can accidentally be transmitted to humans where they can induce a variety of clinical outcomes depending on organ localization. Dirofilaria spp. infection in dogs was assessed using molecular methods (PCR and sequencing) to identify the different Dirofilaria species occurring in 200 dogs from Northern and Central Tunisia. The overall molecular prevalence of Dirofilaria spp. was 17.5% (35/200). The prevalence of D. immitis (14.5%) was significantly higher than for D. repens (3%). Molecular prevalence of D. immitis was significantly higher in suburban compared to urban and rural regions. There was no difference in molecular prevalence of D. immitis or D. repens according to the dogs’ (sex or use). Dirofilaria immitis amplicons (accession numbers KR676386 ) fall into the same clade with D. immitis from China, India and Taiwan. Comparison of the partial sequences of D. repensITS2 rDNA gene ( KR676387 ) revealed 99.6% similarity with D. repens reported in dogs from USA. It had also 97.6% similarity with D. repens from mosquitoes in Czech Republic. High dog parasite burdens should motivate both medical doctors and veterinarians to consider these frequent infections.