Direct Animal Contact Research Articles

Epidemiological analysis of event-based surveillance data of Crimean-Congo Hemorrhagic Fever (CCHF) outbreaks across Balochistan Province, Pakistan, from 2000 to August 2021

Background Crimean-Congo hemorrhagic fever (CCHF) is endemic in Balochistan, caused by the Bunyaviridae family’s tick-borne virus (Nairovirus). The CCHF virus leads to severe viral hemorrhagic fever outbreaks with a fatality rate of 10–40%. This study aims to describe the epidemiological trend of CCHF in Balochistan and provide recommendations for controlling current and future outbreaks. Methods A descriptive approach was adopted for data analysis, utilizing the standard case definition of the Vector-Borne Diseases (VBD) program. “Any person of any age and gender residing in Balochistan from 2000 until August 10, 2021, presenting with the acute onset of illness, featuring a high-grade fever (38.5°C) persisting for more than 3 days but less than 10 days. Individuals should also exhibit any two of the following symptoms: hemorrhagic or purpuric rash, nosebleed, blood in vomit/sputum/stool, or other hemorrhagic symptoms. Moreover, there should be no known predisposing factors for hemorrhagic manifestations, and individuals must have had contact with a confirmed patient or engaged in handling animals and raw animal products.” The study covered cases identified from 2000 to August 10, 2021, and the descriptive study was conducted at the Provincial Disease Surveillance and Response Unit (PDSRU) in Quetta. Frequencies were calculated, and Excel 2016 was used to generate tables and graphs. Results Based on the case definition, 1418 laboratory-confirmed cases of CCHF were identified out of 2542 reported cases from 2000 to August 10, 2021. Most cases (89%, n = 1262) were found to be males. The case fatality rate increased from 5% to 13% over the last decade. The highest number of CCHF cases occurred in 2017 (n = 172), followed by 2005 (n = 108) and 2004 (n = 107). Direct animal contact was reported in 61% of cases, with 22% being butchers and farmers each. CCHF poses a significant public health issue in Balochistan. Conclusion This study provides a detailed overview of CCHF in Balochistan over the last 21 years, recommending the declaration of CCHF as a public health emergency. Establishing a comprehensive tick surveillance system, ecological studies, and health education sessions in collaboration with the livestock department is crucial to prevent future outbreaks.

Q Fever in Greece and Factors of Exposure: A Multiregional Seroprevalence Study.

The epidemiology of Q fever, caused by Coxiella burnetii, varies significantly worldwide. This study aimed to document the prevalence of Coxiella burnetii in Greece by measuring specific IgG antibody levels in serum samples from the general population and high-risk groups, including farmers, veterinarians, and laboratory workers. A multiregional, stratified sampling design was employed, with 1,345 participants from Thessaly and Central Macedonia. Serum samples were tested for Coxiella burnetii IgG antibodies, and multivariate analysis was conducted to identify factors associated with seroprevalence. Overall, 8.1% of participants tested positive for Coxiella burnetii antibodies, with the highest seroprevalence in Larissa (22.2%) and Karditsa (16.1%). High-risk occupational groups, particularly those with direct animal contact, showed a higher seroprevalence (13.6%). Multivariate analysis identified significant associations between seroprevalence and factors such as geographic region, occupation, and gender. The study reveals regional and occupational disparities in Q fever seroprevalence in Greece, particularly in rural areas. These findings underscore the need for targeted public health measures, including heightened surveillance and preventive interventions for high-risk groups.

Overcommitment, Work-Related Behavior, and Cognitive and Emotional Irritation in Veterinarians: A Comparison of Different Veterinary Working Fields.

Mental health is a serious problem among veterinarians. The aim of this study was to analyze work-related behaviors and experience (AVEM), overcommitment (OC), and cognitive and emotional irritation (IS) in different veterinary working fields. The survey included 724 German veterinarians (average age 41.0 ± 9.72 years). Validated questionnaires were used to assess overcommitment, work-related behavior and experience patterns (health-promoting pattern G or S; health-hazardous risk pattern A or B), and irritation in several working fields. A correlation analysis and a multivariate test were performed. Increased OC was observed in 35.8% of veterinarians (mixed animals vs. inspectors, p = 0.042; small vs. mixed animals, p = 0.001). A total of 66% of veterinarians exhibited AVEM risk pattern A or B. There was no significant association of AVEM risk patterns and veterinary specialty. Only the AVEM dimension "tendency toward resignation in the face of failure" differed among working fields (p = 0.04). Regardless of direct animal contact, German veterinarians showed increased psychological stress. Inadequate compensation and prolonged stress are significant factors that can lead to burnout or depression. These risks should be considered in the context of occupational healthcare.

The association between interdigital pilonidal sinus and animal groomers is a historical narrative correlation and not a true occupational hazard

IntroductionPilonidal sinus (PNS) is a small hole or “tunnel” in the skin that frequently occurs in the sacrococcygeal region. Nevertheless, PNS has been reported to occur between the fingers (interdigital) in barbers, hairdressers, and animal groomers. The aim of this study was to estimate the prevalence of interdigital PNS among animal handlers in Bahrain and to treat any patients encountered.MethodsThis is a cross-sectional study with convenience sampling from November 2020 to October 2021. The study participants were animal handlers from stables, veterinary, and pet shops in Bahrain. There were 43 males and 7 females with direct animal contact. 86% of the study population were handling horses, and 15% were handling different types of animals.ResultsNo positive cases of interdigital PNS among participants were found, this might reflect the positive impact of good personal hygiene among our study population. Our study shows that groomers in Bahrain frequently wash their hands after handling animals, and 98% have a daily habit of bathing after work. It was also estimated that 60% of the participants use gloves to handle animals themselves or their waste.DiscussionThis could be the first study looking at the prevalence of interdigital PNS in animal groomers worldwide. The absence of any case report of interdigital PNS among animal groomers in the recent literature strengthens our assumption that the association between interdigital PNS and hair grooming could be a narrative coincidence rather than a true occupational hazard. The present work may help in better understanding of occupation-disease association, and highlights the importance of mass screening of animal handlers for occupation-dependent health problems.

Liver manifestations of tick-borne diseases.

Liver manifestations of tick-borne diseases.

MATHEMATICAL ANALYSIS OF TRANSMISSION DYNAMICS AND CONTROL OF SALMONELLA BACTERIAL INFECTION

The most prevalent health issue is salmonella infection. Every year, between 200 million and 1.3 billion people are infected with Salmonella. Salmonella spreads by direct animal contact, food and drink, and very infrequently, person-to-person contact via the fecal-oral route. It is estimated that 94% of salmonellosis transmission occurs through food. Salmonella infection is, in fact, a bacterial infection. It is crucial to utilize mathematical modeling to describe how biological and biomedical systems behave dynamically. The SIRS model of epidemics is the most often used mathematical model. Describing the patterns of Salmonella infectious disease in animal populations and the human population, we have formulated a SIRS epidemic model in our work. In significant part, the model was developed as a collection of ODEs based on the traits of transmission of infection. The occurrence of infection-free and endemic stable states was initially noted, and stability of the critical points of the model was later proven (infection-free and endemic). Following that, the fundamental reproduction number was calculated using the method of a next-generation matrix. Finally, the numerical simulations of this SIRS model have been completed. The analytical finding is explained using numerical simulations.

Modes of Transmission of Brucellosis in Anbar Governorate, Iraq

Background: Brucellosis is a common and endemic disease in the Anbar governorate. Besides,the Brucella microorganism has different ways of transmission.Objectives: The study aimed to determine the ways of transmission of Brucella organisms tohuman beings in the Al-Anbar governorate.Materials and methods: A retrospective study was carried out on patients visiting the two mainRamadi Teaching Hospitals in Ramadi city, Iraq for the diagnosis and treatment of Brucellosis.Patients with blood-culture-positive brucellae were enrolled in the study. The study includedthe period between February 2002 and March 2005. Data were collected and recorded regardingage, gender, and residence. The possible ways of acquiring the disease were recorded too. Theseincluded ingestion of possibly contaminated foods, butchering of animals, meat cutting, keepinganimals in homes or nearby their livings, cleaning animal places, caring for, milking of them, aidingin their delivery and if they wear gloves, blowing in the mouth of delivered fetuses, their work, andpossible laboratory worker exposure.Results: A total of 312 patients with brucellosis were enrolled in the study. The disease appearsto be more common in rural areas (P-value<0.001). More cases were females in all age groups,and it was more common in the age group 31-40 years. The main mode of transmission is director indirect contact with infected domestic animals (P-value<0.001). Lab workers and ingestionof raw milk and unsafe milk products were the least recorded expected risk for infection. Threerisky behaviors for acquiring brucellosis were also recognized in this study: milking animals, aidingdomestic animals in delivery, and blowing in the mouth of delivered fetuses to promote breathingof the newly delivered animals.Conclusion: Direct or indirect animal contact was the main way of Brucella transmission in theAl-Anbar governorate

Occurrence, antimicrobial resistance and virulence properties of thermophilic Campylobacter coli originating from two different poultry settings

Thermophilic Campylobacter's (Campylobacter coli and Campylobacter jejuni) are usually zoonotic and spread by raw or undercooked meat especially poultry meat, unpasteurized milk, direct animal contact, and contaminated drinking water. In this study, 385 samples from commercial and backyard poultry settings were screened for the presence of Campylobacter spp. which revealed an isolation rate of 3.9% with higher isolation from the chicken caecum (15/113, 13.27%). On antimicrobial susceptibility testing, the highest resistance was observed for tetracycline (11/13, 84.61%) followed by macrolides (8/13, 61.53%), β-lactams (7/13, 53.84%), fluoroquinolones (5/13, 38.45%) and sulphonamide (4/13, 30.76%). Isolates from backyard poultry showed resistance to tetracycline (100%), β-lactam (66.66%), fluoroquinolone (25%), and macrolide (33.33%). Isolates from commercial poultry showed resistance to tetracycline (80%), macrolides (70%), β-lactams (51.66%), fluoroquinolones (42.5%) and sulphonamides (40%). Among the isolates, 92.30% were multi-drug resistant (MDR). Overall, tet(O) gene was observed in 6/11(54.55%) tetracycline resistant isolates. Notably, tet O gene was found in 6/8(75%) isolates from commercial poultry farms and it was absent in backyard poultry isolates. Similarly 23SrRNA and blaOXA-61 genes were detected in 4/8(50%) and 2/8(25%) macrolide and ampicillin resistant isolates, respectively. Among virulence genes, cdtC gene was noticed in all the Campylobacter isolates (100%), cadF in 93.33%, iamA in 80%, flaA in 73.33%, cdtA in 13.33% and, cdtB in 6.66% isolates while dnaJ, ciaB and pldA genes were not detected in any of the isolate. The Campylobacter isolates possessing antimicrobial resistance and virulence genes pose a serious public health threat through food chain.

A statistical modelling approach for source attribution meta-analysis of sporadic infection with foodborne pathogens.

Numerous source attribution studies for foodborne pathogens based on epidemiological and microbiological methods are available. These studies provide empirical data for modelling frameworks that synthetize the quantitative evidence at our disposal and reduce reliance on expert elicitations. Here, we develop a statistical model within a Bayesian estimation framework to integrate attribution estimates from expert elicitations with estimates from microbial subtyping and case‐control studies for sporadic infections with four major bacterial zoonotic pathogens in the Netherlands (Campylobacter, Salmonella, Shiga toxin‐producing E. coli [STEC] O157 and Listeria). For each pathogen, we pooled the published fractions of human cases attributable to each animal reservoir from the microbial subtyping studies, accounting for the uncertainty arising from the different typing methods, attribution models, and year(s) of data collection. We then combined the population attributable fractions (PAFs) from the case‐control studies according to five transmission pathways (domestic food, environment, direct animal contact, human–human transmission and travel) and 11 groups within the foodborne pathway (beef/lamb, pork, poultry meat, eggs, dairy, fish/shellfish, fruit/vegetables, beverages, grains, composite foods and food handlers/vermin). The attribution estimates were biologically plausible, allowing the human cases to be attributed in several ways according to reservoirs, transmission pathways and food groups. All pathogens were predominantly foodborne, with Campylobacter being mostly attributable to the chicken reservoir, Salmonella to pigs (albeit closely followed by layers), and Listeria and STEC O157 to cattle. Food‐wise, the attributions reflected those at the reservoir level in terms of ranking. We provided a modelling solution to reach consensus attribution estimates reflecting the empirical evidence in the literature that is particularly useful for policy‐making and is extensible to other pathogens and domains.

Detection of CWD prions in naturally infected white-tailed deer fetuses and gestational tissues by PMCA

Chronic wasting disease (CWD) is a prevalent prion disease affecting cervids. CWD is thought to be transmitted through direct animal contact or by indirect exposure to contaminated environmental fomites. Other mechanisms of propagation such as vertical and maternal transmissions have also been suggested using naturally and experimentally infected animals. Here, we describe the detection of CWD prions in naturally-infected, farmed white-tailed deer (WTD) fetal tissues using the Protein Misfolding Cyclic Amplification (PMCA) technique. Prion seeding activity was identified in a variety of gestational and fetal tissues. Future studies should demonstrate if prions present in fetuses are at sufficient quantities to cause CWD after birth. This data confirms previous findings in other animal species and furthers vertical transmission as a relevant mechanism of CWD dissemination.

Residential proximity to animal feeding operations and risk of solid tumors in the Agricultural Health Study cohort

Background: Occupational exposure to animals has been associated with several types of cancers, but little is known about risk associated with living near intensive animal farming.Methods: We evaluated associations between residential proximity to animal feeding operations (AFOs) and cancer risk in the Agricultural Health Study, a prospective cohort of pesticide applicators (mostly male farmers) and their spouses. We linked enrollment (1993-1997) addresses for participants in Iowa (33,340 applicators and 20,186 spouses) to a database of permitted AFOs that included animal units (AUs), counts standardized by animal size and manure production. We computed an inverse distance-weighted AU metric that reflects exposure proximity and intensity within 5km of residences. We estimated risk of major solid tumor sites associated with AU metric quintiles using Cox regression (hazard ratio, HR; 95% confidence interval, 95%CI), adjusting for demographics, farming-related factors (occupational pesticide use, direct animal contact), and cancer site-specific potential confounders (e.g., reproductive history). Associations were also estimated separately by animal type (swine, poultry, cattle) and self-reported occupational animal contact.Results: There were 6,137 incident solid tumors diagnosed during follow-up 1993-2015. Among applicators, testicular cancer risk increased with AU quintiles within 5km of the home (HRQ5vsQ1=3.3, 95%CI=1.0-11.0; ptrend=0.03). Prostate cancer risk was significantly elevated in the highest AU quintile (HRQ5vsQ1=1.3; 95%CI=1.1-1.5; ptrend=0.0001). For lung cancer, there was an inverse, but non-significant trend with increasing AUs (HRQ5vsQ1=0.80; 95%CI=0.50-1.2; ptrend=0.09). Among spouses, uterine cancer risk was elevated (HRQ5vsQ1=1.9, 95%CI=1.2-2.9; ptrend=0.03). Risk of breast cancer increased with cattle AUs (ptrend=0.01), but not for other animal types. We observed no effect modification by animal-related work for any cancer site.Conclusions: Our results suggest that residential proximity to AFOs may influence risk of certain solid tumors, even after consideration of farming activities and other risk factors. These findings are novel, but further evaluation is needed to identify etiologic agents.

Transition Pathways Toward the Prudent Use of Antimicrobials: The Case of Free-Range Broiler Farmers in France.

Reducing antimicrobial use (AMU) on farms is key for controlling the rise of resistant bacteria that have the potential capacity to infect humans via direct animal contact or via the food chain or the environment. To reduce AMU, antimicrobials must be used in a prudent and rational manner. Extensive efforts have been made recently to identify the cognitive and behavioral barriers to the appropriate use of antimicrobials by various livestock sector stakeholders. However, most studies carried out thus far have only partly captured the dynamic and systemic dimension of the processes involved in changes of practices related to AMU on farms. To shed light on the transition pathways implemented to reduce AMU, a qualitative study was conducted in France based on 28 semi-structured interviews with farmers, technicians and veterinarians from the free-range broiler production sector. Based on the thematic analysis of verbatims, we identified technical improvements which are key contributors to reduced AMU. We also highlighted some gaps in knowledge regarding AMU and antimicrobial resistance. We found that, rather than individual motivations alone, the extent to which farmers are embedded in collective organizations is decisive for changes in practices, and downstream operators (distributors and slaughterers) play a key role in the beginning of AMU transition pathways. As a result, we show that change in AMU requires a global rethinking of the overall socio-technical system rather than modifications of a single element in a farming system. Our results also highlight that transition pathways toward reduced AMU cannot just rely on trigger events, but also involves medium or long-term processes, with actors' experiences and practices being modified on an incremental basis over time. Our study sheds light on the need for multi and trans-disciplinary research involving the social sciences to analyze interactions between stakeholders and the collective actions implemented to tackle the challenge of AMU reduction.

Farm animal contact is associated with progression to Hemolytic uremic syndrome in patients with Shiga toxin-producing Escherichia coli — Indiana, 2012–2018

BackgroundHemolytic uremic syndrome (HUS) is a life-threatening complication of Shiga toxin-producing Escherichia coli (STEC) infection. The relationship between STEC exposure and severity of clinical outcomes is not well documented. We examined whether direct contact with farm animals increased the likelihood of HUS among Indiana residents diagnosed with STEC. MethodsExposure data for laboratory-confirmed STEC cases among Indiana residents during 2012–2018 were retrieved. Logistic regression and mediation analysis were performed to determine the extent to which a history of direct contact with farm animals was associated with post-diarrheal HUS independent of age and mediated by stx2 gene presence. ResultsA total of 784 STEC cases were retrieved. Of these, 46 (6%) developed HUS. Complete exposure data were available for 600 (77%) cases. A total of 24 (52%) HUS patients reported direct contact with farm animals, while 114 (21%) STEC patients who did not develop HUS reported this exposure. Among all STEC cases, HUS was associated with direct farm animal contact after adjusting for age (OR = 3.40, 95% CI: 1.81, 6.40). Detection of stx2 genes mediated 12% of the association between farm animal contact and HUS. ConclusionsDirect farm animal contact was a risk factor for development of HUS among laboratory-confirmed STEC cases, independent of stx2 presence. Direct farm animal contact should be considered a potential predictor of progression to HUS when patients present for care and the mechanism for its effect on virulence investigated.

Burden of foodborne disease in the Netherlands: from science to policy

Abstract In the Netherlands, the Ministry of Health mandates the National Institute for Public Health and the Environment (RIVM) to provide annual updates of the number of illnesses, disease burden and cost-of-illness caused by an agreed-upon standard panel of 14 enteric pathogens. These pathogens are mainly transmitted by food, but also via direct contact with animals, environment-mediated and human-to-human transmission routes. The disease burden is expressed in DALYs (Disability Adjusted Life Years), a metric integrating morbidity and mortality into one unit. Furthermore, the cost-of-illness (COI) related to these 14 pathogens is estimated and expressed in euros. The COI estimates include healthcare costs, the costs for the patient and/or his family, such as travel expenses, as well as costs in other sectors, for example due to productivity losses. Moreover, using different approaches to source attribution, the estimated DALYs and associated COI estimates are attributed to five major transmission pathways (i.e. food, environment, direct animal contact, human-human transmission, and travel) and 11 food groups within the foodborne pathway itself. The most recent DALY and COI estimates referring to the year 2018 show that the 14 pathogens in question are cumulatively responsible for about 11,000 DALYs and €426 million costs for the Dutch population in 2018, with a share for foodborne transmission being estimated at 4,300 DALYs and €171 million costs, which is comparable to previous years. These estimates have been providing vital insights for policy making as to guide public health interventions and resource allocation for over two decades in the Netherlands. Herewith, the approach and outcomes of the burden of disease and COI estimates in the Netherlands will be presented, with a focus on how these estimates enable policy-makers and the scientific community to monitor trends, generate scientific hypotheses, and undertake public health actions.

Shedding and stability of CWD prion seeding activity in cervid feces.

CWD is an emergent prion disease that now affects cervid species on three continents. CWD is efficiently spread in wild and captive populations, likely through both direct animal contact and environmental contamination. Here, by longitudinally assaying in feces of CWD-exposed white-tailed deer by RT-QuIC, we demonstrate fecal shedding of prion seeding activity months before onset of clinical symptoms and continuing throughout the disease course. We also examine the impact of simulated environmental conditions such as repeated freeze-thaw cycles and desiccation on fecal prion seeding activity. We found that while multiple (n = 7) freeze-thaw cycles substantially decreased fecal seeding activity, desiccation had little to no effect on seeding activity. Finally, we examined whether RT-QuIC testing of landscape fecal deposits could distinguish two premises with substantial known CWD prevalence from one in which no CWD-infected animals had been detected. In the above pilot study, this distinction was possible. We conclude that fecal shedding of CWD prions occurs over much of the disease course, that environmental factors influence prion seeding activity, and that it is feasible to detect fecal prion contamination using RT-QuIC.

Unidirectional animal-to-human transmission of methicillin-resistant Staphylococcus aureus ST398 in pig farming; evidence from a surveillance study in southern Italy

BackgroundLivestock-associated methicillin-resistant Staphylococcus aureus (MRSA) belonging to clonal complex 398 is recognized as an occupational hazard for workers employed in intensive animal husbandry, especially in the swine-breeding chain. In this study, we compared the prevalence and epidemiological type of MRSA isolates from swine and farm workers in a large area of southern Italy.MethodsBetween January and March 2018, 88 workers from 32 farms where we had previously performed a survey for MRSA colonization of farmed pigs, were sampled by nasal swabbing. A follow-up investigation was conducted on seven workers 1 year after primary screening. MRSA isolates were characterized by MLST, spa and SCCmec typing, and tested for susceptibility to 15 antimicrobials. Epidemiological correlations between human and swine MRSA isolates were supported by Rep-MP3 and RAPD PCR fingerprinting, and whole-genome sequencing.ResultsThe overall colonization rate of MRSA in swine farm workers was 21.6%, being significantly higher in intensive farms and in workers with direct animal contact. All human MRSA isolates were multi-drug resistant, belonged to the ST398 livestock clade, and did not carry Panton-Valentine leukocidin and enterotoxin genes. Notably, 94.1% of human MRSA isolates belonged to the same epidemiological type as swine MRSA isolates from the corresponding farm. Persistent MRSA carriage was documented in some workers 1 year after primary sampling.ConclusionsWe report a high prevalence of MRSA among swine farm workers, with higher colonization rates associated with intensive breeding and animal exposure. Our findings suggest unidirectional animal-to-human transmission of LA-MRSA and denote the high zoonotic transmissibility of the ST398 livestock clade.

Is Raw Milk Still Vehicle for Transmitting Listeria species To Pregnant Women?

Numerous reports have been published about the occurrence of Listeria spp. in different food sources including milk of different dairy species. A total of 250 milk samples including; cows (150), buffaloes (50) and sheep (50) were collected from some private farms of dairy animals and retailers. At the same time, 50 aborted women attending Al Shatbi Hospital, Alexandria were investigated for isolation of Listeria species from whole blood samples and vaginal swabs. It was found that the rate of isolation of Listeria spp. from milk samples was 7.33, 8 and 12% in the examined samples of cattle, buffaloes and sheep, respectively with significant association between the rates of isolation. Identification of Listeria spp. isolated from milk samples clarified the presence of L. monocytogenes (2.4%), L. ivanovii (2%), L. innocua (1.2%) and L. grayi (2.8%). Concerning aborted women, it was found that Listeria spp. were isolated from only 2 out of 50 vaginal swabs (4%) while we failed to isolate Listeria spp. from blood samples. Moreover, the 2 isolates were identified as L. monocytogenes. Statistical analysis showed non-significant association between the manners of milk consumption and the rate of isolation of L. monocytogenes from aborted women where positive cases informed that they consumed milk in regular manner. Also, statistical analysis showed non-significant association between presence of direct animal contact and the rate of isolation of L. monocytogenes from aborted women where one positive case had animal contact and the other had no animal contact. Finally, multiplex PCR was employed for detection of hylA and actA virulence genes for characterization of L. monocytogenes isolated from milk and aborted women. Based on the obtained results in the current study, it was clear that milk was considered to be potential vehicle for Listeria spp. that might constitute a zoonotic risk for pregnant women. Although the rate of isolation of listeria from aborted women was relatively low, the zoonotic hazard must not be neglected and further future studies should be carried out to highlight the zoonotic importance. In addition, it was advisable to thorough heat treating of milk before consumption and veterinarians should do their efforts in controlling zoonotic diseases by encouraging prevention.

Spread of an Experimental Salmonella Derby Infection in Antibiotic-Treated or Lawsonia intracellularis Vaccinated Piglets.

Simple SummaryToday, pigs repeatedly suffer from diarrhoea which requires treatment with antibiotics. Infections with Lawsonia intracellularis are one of the most common diseases, which, although usually subclinical, have a negative impact on performance. The alternative to antibiotic treatment is vaccinations against Lawsonia intracellularis, not least because antibiotic treatments are suspected of promoting the spread of certain zoonotic pathogens. A study was carried out with piglets from a farm that had a problem with Lawsonia intracellularis infections. In half of the animals, antibiotic treatments with tylosin were carried out in piglet rearing. In the other group, the piglets had been vaccinated against Lawsonia intracellularis as suckling piglets. Individual animals from both groups were subsequently artificially infected with Salmonella as piglets. A total of 72 animals were included in the study, 12 of which were primarily infected. The other animals had the possibility of becoming infected via direct animal contact or the faeces of infected animals. The detection of Salmonella in stool and intestinal lymph nodes was significantly higher in animals previously treated with antibiotics. Treatment with tylosin may significantly increase the spread of the Salmonella infection not observed after early Lawsonia intracellularis vaccination.Lawsonia intracellularis infections are a common reason for antibiotic treatment in pig production. Experimental studies in animals naturally infected with Lawsonia intracellularis comparing the course of an experimental Salmonella infection in piglets previously treated with tylosin or vaccinated against Lawsonia intracellularis are scarce. A total of 72 seven-week-old Salmonella-free pigs were taken from a herd with a Lawsonia intracellularis history in piglet rearing. The pigs were divided into two groups with three replicates each. Animals had either been previously treated with tylosin (10 mg/kg body weight) for seven days (AB+VAC−) or had been vaccinated as suckling pigs by drenching (Enterisol®Ileitis; AB−VAC+). Two animals per replicate were primarily infected with Salmonella Derby (1.04 × 108 colony-forming units per animal). The detection of Salmonella in faeces (p < 0.0001, odds ratio: 3.8364) and in the ileocaecal lymph nodes (p = 0.0295, odds ratio: 3.5043) was significantly more frequent in AB+VAC− animals. Overall, the odds ratio for detecting Salmonella in any substrate or organ was significantly higher in the AB+VAC− group animals (p = 0.0004, odds ratio: 5.9091). Treatment with tylosin can significantly increase the spread of a Salmonella infection, which is not observed after early Lawsonia intracellularis vaccination.

A spatial and temporal analysis of risk factors associated with sporadic Shiga toxin-producing Escherichia coli O157 infection in England between 2009 and 2015.

Infection with STEC O157 is relatively rare but has potentially serious sequelae, particularly for children. Large outbreaks have prompted considerable efforts designed to reduce transmission primarily from food and direct animal contact. Despite these interventions, numbers of infections have remained constant for many years and the mechanisms leading to many sporadic infections remain unclear.Here, we show that two-thirds of all cases reported in England between 2009 and 2015 were sporadic. Crude rates of infection differed geographically and were highest in rural areas during the summer months. Living in rural areas with high densities of cattle, sheep or pigs and those served by private water supplies were associated with increased risk. Living in an area of lower deprivation contributed to increased risk but this appeared to be associated with reported travel abroad. Fresh water coverage and residential proximity to the coast were not risk factors.To reduce the overall burden of infection in England, interventions designed to reduce the number of sporadic infections with STEC should focus on the residents of rural areas with high densities of livestock and the effective management of non-municipal water supplies. The role of sheep as a reservoir and potential source of infection in humans should not be overlooked.

The topology of between-herd cattle contacts in a mixed farming production system in western Kenya

In many livestock production systems in sub-Saharan Africa, cattle are owned by individual keepers but regularly mix with animals from other herds while grazing communal land, at watering points or through the use of shared bulls for breeding and ploughing. Such contacts may have important implications for disease transmission and control but are not well documented.We describe between-farm contacts in Kimilili sub-county of Bungoma County, a mixed farming area of predominately smallholder farmers. Between-farm contacts occurring during grazing or at shared water points over the past four weeks were captured in seven randomly selected villages using a photo-elicitation tool. The use of shared bulls for breeding and ploughing and cattle introductions from farms within the same village in the past 12 months were also captured. Contact networks were constructed for each contact type in each village.In total 329 farms were included in the study. Networks resembled undirected scale-free graphs with a network density ranging between 9.6 and 14.0. Between 45.6 and 100% of the farms in each study village had been in contact over the past four weeks through grazing and watering contacts. Between 88.9 and 100% were considered to have been in contact over the past 12 months. The topology of the networks was heterogeneous, with some farms exhibiting a high degree of contact. The degree of farm contact and distances between farms were negatively correlated (Pearson correlation coefficient range −0.2 to −0.4).Effective disease control and surveillance must take into consideration the frequency and range of contacts that occur between farms within a single village. Cattle keepers are highly interconnected and pathogens that are transmitted through direct or indirect animal contact would be expected to spread rapidly in the study system. However, the observed heterogeneity in between-farm contact may present opportunities for interventions to be targeted to particular herds to limit infectious disease spread.