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Department of Veterinary Medicine

Cambridge Veterinary School
 

TB vaccine may enable elimination of the disease in cattle by reducing its spread

Departmental research news - 3 hours 58 min ago

The research, led by the University of Cambridge and Penn State University, improves prospects for the elimination and control of bovine tuberculosis (TB), an infectious disease of cattle that results in large economic costs and health impacts across the world.  

This is the first study to show that BCG-vaccinated cattle infected with TB are substantially less infectious to other cattle. This remarkable indirect effect of the vaccine beyond its direct protective effect has not been measured before.

The spillover of infection from livestock has been estimated to account for about 10% of human tuberculosis cases. While such zoonotic TB (zTB) infections are most commonly associated with gastro-intestinal infections related to drinking contaminated milk, zTB can also cause chronic lung infections in humans. Lung disease caused by zTB can be indistinguishable from regular tuberculosis, but is more difficult to treat due to natural antibiotic resistance in the cattle bacteria.

TB remains endemic in many countries around the world, including in Europe and the Americas, where its control costs farmers and taxpayers hundreds of millions of dollars each year.

The study is published today in the journal Science.

In the study, carried out in Ethiopia, researchers examined the ability of the vaccine, Bacillus Calmette-Guérin (BCG), to directly protect cattle that receive it, as well as to indirectly protect both vaccinated and unvaccinated cattle by reducing TB transmission. Vaccinated and unvaccinated animals were put into enclosures with naturally infected animals, in a novel crossover design performed over two years.

“Our study found that BCG vaccination reduces TB transmission in cattle by almost 90%. Vaccinated cows also developed significantly fewer visible signs of TB than unvaccinated ones. This suggests that the vaccination not only reduces the progression of the disease, but that if vaccinated animals become infected, they are substantially less infectious to others,” said Andrew Conlan, Associate Professor of Epidemiology at the University of Cambridge’s Department of Veterinary Medicine and a corresponding author of the study.

Using livestock census and movement data from Ethiopia, the team developed a transmission model to explore the potential for routine vaccination to control bovine tuberculosis.

“Results of the model suggest that vaccinating calves within the dairy sector of Ethiopia could reduce the reproduction number of the bacterium — the R0 — to below 1, arresting the projected increase in the burden of disease and putting herds on a pathway towards elimination of TB,” Conlan said.

The team focused their studies in Ethiopia, a country with the largest cattle herd in Africa and a rapidly growing dairy sector that has a growing burden of bovine tuberculosis and no current control program, as a representative of similarly situated transitional economies.

“Bovine tuberculosis is largely uncontrolled in low- and middle-income countries, including Ethiopia,” said Abebe Fromsa, associate professor of agriculture and veterinary medicine at Addis Ababa University in Ethiopia and the study’s co-lead author. “Vaccination of cattle has the potential to provide significant benefits in these regions.”

“For over a hundred years, programs to eliminate bovine tuberculosis have relied on intensive testing and slaughtering of infected animals,” said Vivek Kapur, professor of microbiology and infectious diseases and Huck Distinguished Chair in Global Health at Penn State and a corresponding author of the study.

He added: “This approach is unimplementable in many parts of the world for economic and social reasons, resulting in considerable animal suffering and economic losses from lost productivity, alongside an increased risk of spillover of infection to humans. By vaccinating cattle, we hope to be able to protect both cattle and humans from the consequences of this devastating disease.”

Professor James Wood, Alborada Professor of Equine and Farm Animal Science in the University of Cambridge’s Department of Veterinary Medicine, noted that despite TB being more prevalent in lower-income countries, the United Kingdom, Ireland and New Zealand also experience considerable economic pressures from the disease which continues to persist despite intensive and costly control programs.

Wood said: “For over twenty-years the UK government has pinned hopes on cattle vaccination for bovine tuberculosis as a solution to reduce the disease and the consequent costs of the controls. These results provide important support for the epidemiological benefit that cattle vaccination could have to reduce rates of transmission to and within herds.”

This research was supported by The Bill & Melinda Gates Foundation, as well as the Biotechnology and Biological Sciences Research Council; Foreign, Commonwealth and Development Office; Economic & Social Research Council; Medical Research Council; Natural Environment Research Council; and Defence Science & Technology.

Reference: Fromsa, A. et al: ‘BCG vaccination of cattle reduces transmission of bovine tuberculosis, improving the prospects for elimination.’ Science, March 2024. DOI: 10.1126/science.adl3962

Vaccination not only reduces the severity of TB in infected cattle, but reduces its spread in dairy herds by 89%, research finds.

Our study suggests that vaccination not only reduces the progression of the disease, but that if vaccinated animals become infected, they are substantially less infectious to others.Andrew ConlanGetty/ kamisokaHerd of cows in a grassy field


The text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright ©University of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Departmental Seminars - Wed, 27/03/2024 - 13:40
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Chaired by Cassia Hare

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Tue 23 Jul 16:00: Active Surveillance of Neglected Tropical Diseases: A Fresh Push to Identify Reservoir Hosts

Departmental Seminars - Fri, 22/03/2024 - 15:08
Active Surveillance of Neglected Tropical Diseases: A Fresh Push to Identify Reservoir Hosts

Abstract: The recent wave of pandemic/epidemics in the world has necessitated that Africa join the global push to not only to be ready for future pandemics but to also preempt them. Africa is plagued with a lot of neglected tropical diseases, many of them caused by neurotropic viruses. With minimal funding of these diseases, the burden they create on quality of life and productivity of animals has not been well estimated. More important is the need for active surveillance of possible reservoir hosts for some of these Neglected Tropical Diseases, so as to proper understand their epidemiology. In this presentation, I will be speaking on West Nile, and Crimean Congo Heamorrhagic Fever viruses, and the roles that reservoirs may be playing for reverse zoonosis.

Short Citation: James Olukayode Olopade graduated with the DVM (Veterinary) degree in 1992 and obtained his MSc and PhD in 2003 and 2006, respectively, all from the University of Ibadan. He was promoted full Professor in 2011. James carried out postdoctoral trainings in Marine Biology Laboratory Woodshole, USA , as an International Brain Research Organisation (IBRO) Fellow at Penn State University, USA in 2008, and as a MacArthur and Alexander von Humboldt Fellow, both at the University of Wurzburg, Germany. He has served as Editor in Chief, Nigerian Veterinary Journal and Dean, Faculty of Veterinary Medicine. His current research areas are in neuroscience, comparative anatomy and surveillance biology. He has been funded by a variety of organisations including the International Society of Neurochemistry; the International Brain Research Organisation, the Alexander von Humboldt Foundation; the Tertiary Education Trust Fund, Nigeria, and the Cambridge Alborada Grant (UK) amongst others. He has over 160 research publications including 4 copyrights and is the most cited veterinarian in Africa as per brain research. James Olopade is currently the Principal Investigator of Alexander von Humboldt Research Hub for Zoonotic Arboviral Diseases (HRH-ZAD), a €750,000 Humboldt Research Hub funding for pandemic preparedness, and also the Director of the Veterinary Teaching Hospital, at the University of Ibadan in Nigeria.

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Wed 15 May 12:00: How use of SSRI impacts placenta and mammary gland development

Departmental Seminars - Mon, 18/03/2024 - 16:42
How use of SSRI impacts placenta and mammary gland development

Laura L. Hernandez, Professor-Lactation Physiology Department of Animal and Dairy Sciences University of Wisconsin-Madison

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Wed 15 May 12:00: Title to be confirmed

Departmental Seminars - Mon, 18/03/2024 - 10:04
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Laura L. Hernandez, Professor-Lactation Physiology Department of Animal and Dairy Sciences University of Wisconsin-Madison

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Departmental Seminars - Mon, 18/03/2024 - 09:57
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Estimating the health effects of COVID-19-related immunisation disruptions in 112 countries during 2020-30: a modelling study

Latest publications - Thu, 14/03/2024 - 10:00

Lancet Glob Health. 2024 Apr;12(4):e563-e571. doi: 10.1016/S2214-109X(23)00603-4.

ABSTRACT

BACKGROUND: There have been declines in global immunisation coverage due to the COVID-19 pandemic. Recovery has begun but is geographically variable. This disruption has led to under-immunised cohorts and interrupted progress in reducing vaccine-preventable disease burden. There have, so far, been few studies of the effects of coverage disruption on vaccine effects. We aimed to quantify the effects of vaccine-coverage disruption on routine and campaign immunisation services, identify cohorts and regions that could particularly benefit from catch-up activities, and establish if losses in effect could be recovered.

METHODS: For this modelling study, we used modelling groups from the Vaccine Impact Modelling Consortium from 112 low-income and middle-income countries to estimate vaccine effect for 14 pathogens. One set of modelling estimates used vaccine-coverage data from 1937 to 2021 for a subset of vaccine-preventable, outbreak-prone or priority diseases (ie, measles, rubella, hepatitis B, human papillomavirus [HPV], meningitis A, and yellow fever) to examine mitigation measures, hereafter referred to as recovery runs. The second set of estimates were conducted with vaccine-coverage data from 1937 to 2020, used to calculate effect ratios (ie, the burden averted per dose) for all 14 included vaccines and diseases, hereafter referred to as full runs. Both runs were modelled from Jan 1, 2000, to Dec 31, 2100. Countries were included if they were in the Gavi, the Vaccine Alliance portfolio; had notable burden; or had notable strategic vaccination activities. These countries represented the majority of global vaccine-preventable disease burden. Vaccine coverage was informed by historical estimates from WHO-UNICEF Estimates of National Immunization Coverage and the immunisation repository of WHO for data up to and including 2021. From 2022 onwards, we estimated coverage on the basis of guidance about campaign frequency, non-linear assumptions about the recovery of routine immunisation to pre-disruption magnitude, and 2030 endpoints informed by the WHO Immunization Agenda 2030 aims and expert consultation. We examined three main scenarios: no disruption, baseline recovery, and baseline recovery and catch-up.

FINDINGS: We estimated that disruption to measles, rubella, HPV, hepatitis B, meningitis A, and yellow fever vaccination could lead to 49 119 additional deaths (95% credible interval [CrI] 17 248-134 941) during calendar years 2020-30, largely due to measles. For years of vaccination 2020-30 for all 14 pathogens, disruption could lead to a 2·66% (95% CrI 2·52-2·81) reduction in long-term effect from 37 378 194 deaths averted (34 450 249-40 241 202) to 36 410 559 deaths averted (33 515 397-39 241 799). We estimated that catch-up activities could avert 78·9% (40·4-151·4) of excess deaths between calendar years 2023 and 2030 (ie, 18 900 [7037-60 223] of 25 356 [9859-75 073]).

INTERPRETATION: Our results highlight the importance of the timing of catch-up activities, considering estimated burden to improve vaccine coverage in affected cohorts. We estimated that mitigation measures for measles and yellow fever were particularly effective at reducing excess burden in the short term. Additionally, the high long-term effect of HPV vaccine as an important cervical-cancer prevention tool warrants continued immunisation efforts after disruption.

FUNDING: The Vaccine Impact Modelling Consortium, funded by Gavi, the Vaccine Alliance and the Bill & Melinda Gates Foundation.

TRANSLATIONS: For the Arabic, Chinese, French, Portguese and Spanish translations of the abstract see Supplementary Materials section.

PMID:38485425 | DOI:10.1016/S2214-109X(23)00603-4

Wed 15 May 12:00: Title to be confirmed

Departmental Seminars - Fri, 08/03/2024 - 17:01
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Laura L. Hernandez, Ph.D. (she, her, hers) Professor-Lactation Physiology Department of Animal and Dairy Sciences Affiliate Professor-Obstetrics and Gynecology

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Genetic mutation in a quarter of all Labradors hard-wires them for obesity

Departmental research news - Wed, 06/03/2024 - 19:06

This obesity-driving combination means that dog owners must be particularly strict with feeding and exercising their Labradors to keep them slim.

The mutation is in a gene called POMC, which plays a critical role in hunger and energy use.

Around 25% of Labradors and 66% of flatcoated retriever dogs have the POMC mutation, which researchers previously showed causes increased interest in food and risk of obesity.

The new study reveals how the mutation profoundly changes the way Labradors and flatcoated retrievers behave around food. It found that although they don’t need to eat more to feel full, they are hungrier in between meals.

In addition, dogs with the POMC mutation were found to use around 25% less energy at rest than dogs without it, meaning they don’t need to consume as many calories to maintain a healthy body weight.

“We found that a mutation in the POMC gene seems to make dogs hungrier. Affected dogs tend to overeat because they get hungry between meals more quickly than dogs without the mutation,” said Dr Eleanor Raffan, a researcher in the University of Cambridge’s Department of Physiology, Development and Neuroscience who led the study.

She added: “All owners of Labradors and flatcoated retrievers need to watch what they’re feeding these highly food-motivated dogs, to keep them a healthy weight. But dogs with this genetic mutation face a double whammy: they not only want to eat more, but also need fewer calories because they’re not burning them off as fast.”

The POMC mutation was found to alter a pathway in the dogs’ brains associated with body weight regulation. The mutation triggers a starvation signal that tells their body to increase food intake and conserve energy, despite this being unnecessary.

The results are published today in the journal Science Advances.

Raffan said: “People are often rude about the owners of fat dogs, blaming them for not properly managing their dogs’ diet and exercise. But we’ve shown that Labradors with this genetic mutation are looking for food all the time, trying to increase their energy intake. It’s very difficult to keep these dogs slim, but it can be done.”

The researchers say owners can keep their retrievers distracted from this constant hunger by spreading out each daily food ration, for example by using puzzle feeders or scattering the food around the garden so it takes longer to eat.

In the study, 87 adult pet Labrador dogs - all a healthy weight or moderately overweight - took part in several tests including the ‘sausage in a box’ test.

First, the dogs were given a can of dogfood every 20 minutes until they chose not to eat any more. All ate huge amounts of food, but the dogs with the POMC mutation didn’t eat more than those without it. This showed that they all feel full with a similar amount of food.

Next, on a different day, the dogs were fed a standard amount of breakfast. Exactly three hours later they were offered a sausage in a box and their behaviour was recorded. The box was made of clear plastic with a perforated lid, so the dogs could see and smell the sausage, but couldn’t eat it.

The researchers found that dogs with the POMC mutation tried significantly harder to get the sausage from the box than dogs without it, indicating greater hunger.

The dogs were then allowed to sleep in a special chamber that measured the gases they breathed out. This revealed that dogs with the POMC mutation burn around 25% fewer calories than dogs without it.

The POMC gene and the brain pathway it affects are similar in dogs and humans. The new findings are consistent with reports of extreme hunger in humans with POMC mutations, who tend to become obese at an early age and develop a host of clinical problems as a result.

Drugs currently in development for human obesity, underactive sexual desire and certain skin conditions target this brain pathway, so understanding it fully is important.

A mutation in the POMC gene in dogs prevents production of two chemical messengers in the dog brain, beta-melanocyte stimulating hormone (β-MSH) and beta-endorphin, but does not affect production of a third, alpha-melanocyte stimulating hormone (α-MSH).

Further laboratory studies by the team suggest that β-MSH and beta-endorphin are important in determining hunger and moderating energy use, and their role is independent of the presence of α-MSH. This challenges the previous belief, based on research in rats, that early onset human obesity due to POMC mutations is caused only by a lack of α-MSH. Rats don’t produce beta-melanocyte stimulating hormone, but humans and dogs produce both α- and β-MSH.

The research was funded by The Dogs Trust and Wellcome.

Reference: Dittmann, M T et al: ‘Low resting metabolic rate and increased hunger due to β-MSH and β-endorphin deletion in a canine model.’ Science Advances, March 2024. DOI: 10.1126/sciadv.adj3823

New research finds around a quarter of Labrador retriever dogs face a double-whammy of feeling hungry all the time and burning fewer calories due to a genetic mutation.

Labradors with this genetic mutation are looking for food all the time, trying to increase their energy intake. It’s very difficult to keep these dogs slim, but it can be done.Eleanor Raffan A quarter of Labradors are hard-wired for obesity Jane GoodallLabrador retriever dog


The text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright ©University of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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A metagenomic catalog of the early-life human gut virome

Latest publications - Thu, 29/02/2024 - 11:00

Nat Commun. 2024 Feb 29;15(1):1864. doi: 10.1038/s41467-024-45793-z.

ABSTRACT

Early-life human gut microbiome is a pivotal driver of gut homeostasis and infant health. However, the viral component (known as "virome") remains mostly unexplored. Here, we establish the Early-Life Gut Virome (ELGV), a catalog of 160,478 non-redundant DNA and RNA viral sequences from 8130 gut virus-like particles (VLPs) enriched or bulk metagenomes in the first three years of life. By clustering, 82,141 viral species are identified, 68.3% of which are absent in existing databases built mainly from adults, and 64 and 8 viral species based on VLPs-enriched and bulk metagenomes, respectively, exhibit potentials as biomarkers to distinguish infants from adults. With the largest longitudinal population of infants profiled by either VLPs-enriched or bulk metagenomic sequencing, we track the inherent instability and temporal development of the early-life human gut virome, and identify differential viruses associated with multiple clinical factors. The mother-infant shared virome and interactions between gut virome and bacteriome early in life are further expanded. Together, the ELGV catalog provides the most comprehensive and complete metagenomic blueprint of the early-life human gut virome, facilitating the discovery of pediatric disease-virome associations in future.

PMID:38424077 | DOI:10.1038/s41467-024-45793-z

A retrospective observational cohort study on the postoperative respiratory complications and their risk factors in brachycephalic dogs undergoing BOAS surgery: 199 cases (2019-2021)

Latest publications - Tue, 27/02/2024 - 11:00

J Small Anim Pract. 2024 Feb 27. doi: 10.1111/jsap.13707. Online ahead of print.

ABSTRACT

OBJECTIVES: To observe the occurrence of postanaesthetic respiratory complications and to determine their prevalence and risk factors in dogs undergoing brachycephalic obstructive airway syndrome surgery.

MATERIALS AND METHODS: Data from 199 clinical records were retrospectively analysed. Univariable logistic regression followed by multivariable logistic regression was used to identify associations between the dependent variables (set as the postoperative respiratory complications observed in the study dogs) and various independent covariates. The quality of model-fit was assessed using the likelihood ratio test. P≤0.05 was considered statistically significant.

RESULTS: Four postoperative respiratory complications were observed: hypoxaemia (n=10/199; 5%), dyspnoea requiring tracheal re-intubation (n=13/199, 7%), dyspnoea requiring tracheostomy (n=10/199, 5%) and aspiration pneumonia (n=12/199, 6%). Univariable logistic regression showed an association between postoperative aspiration pneumonia and increasing body condition score and American Society of Anaesthesiology classification; however, when these covariates were evaluated in the multivariable model significance was not maintained. Risk factors for tracheostomy were preoperative and postoperative aspiration pneumonia (odds ratio: 9.52, 95% confidence interval: 1.56 to 57.93) and increasing brachycephalic obstructive airway syndrome grade (odds ratio: 4.65, 95% confidence interval: 0.79 to 27.50).

CLINICAL SIGNIFICANCE: High brachycephalic obstructive airway syndrome grade and aspiration pneumonia, either developing peri-operatively or as pre-existing condition, may represent risk factors for postoperative tracheostomy. Preoperative diagnosis of aspiration pneumonia may further increase the risk of postoperative complications.

PMID:38413137 | DOI:10.1111/jsap.13707

The mobility of the brachycephalic canine nostril in relation to the degree of nostril stenosis

Latest publications - Sat, 24/02/2024 - 11:00

Vet J. 2024 Feb 22:106085. doi: 10.1016/j.tvjl.2024.106085. Online ahead of print.

ABSTRACT

Previous studies have shown that the most reliable external conformational risk factor of whether a brachycephalic dog will develop Brachycephalic Obstructive Airway Syndrome (BOAS) is the status of nostril stenosis, assessed as a static observation using the brachycephalic nostril grading scheme. The nostrils however are a dynamic structure, opening further when the dog is exercising, sniffing or panting. The hypothesis of this study was that brachycephalic dogs with open or mildly stenotic nostrils are more likely to have nostril mobility whilst dogs with moderately or severely stenotic nostrils are more likely to have immobile nostrils. A retrospective study of dogs presented for BOAS assessment at two UK referral centres between 2012-2020 was performed. Data extracted included nares stenosis status and nares mobility. A mesocephalic pilot control group was recruited from a third referral centre. Statistical analysis was performed with χ2, Cochran-Armitage, spearman's rho and linear-by-linear tests as appropriate. Of the 974 brachycephalic dogs included in the study: 124 had open nostrils (68.5% mobile); 212 mildly stenotic nostrils (58.5% mobile); 379 moderately stenotic nostrils (35% mobile) and 259 severely stenotic nostrils (19.3% mobile). The nostril stenotic status was significantly associated with nostril wing mobility (χ2 =135.55; P<0.0001). When considering open and mildly stenotic (considered acceptable) nostrils versus moderate and severely stenotic nostrils, mobility was 62% versus 25.5% (χ2= 135.88; P = <0.0001). All 27 mesocephalic dogs had nostril mobility. Brachycephalic dogs with moderate and severely stenotic nares have reduced nasal mobility compared to brachycephalic dogs with mildly stenotic and open nares. Data is further evidence that dogs with moderately and severely stenotic nares should not be bred.

PMID:38401643 | DOI:10.1016/j.tvjl.2024.106085

A Practical Guide to Full Value of Vaccine Assessments

Latest publications - Sat, 24/02/2024 - 11:00

Vaccines (Basel). 2024 Feb 16;12(2):201. doi: 10.3390/vaccines12020201.

ABSTRACT

Articulating the wide range of health, social and economic benefits that vaccines offer may help to overcome obstacles in the vaccine development pipeline. A framework to guide the assessment and communication of the value of a vaccine-the Full Value of Vaccine Assessment (FVVA)-has been developed by the WHO. The FVVA framework offers a holistic assessment of the value of vaccines, providing a synthesis of evidence to inform the public health need of a vaccine, describing the supply and demand aspects, its market and its impact from a health, financial and economic perspective. This paper provides a practical guide to how FVVAs are developed and used to support investment in vaccines, ultimately leading to sustained implementation in countries. The FVVA includes a range of elements that can be broadly categorised as synthesis, vaccine development narrative and defining vaccine impact and value. Depending on the features of the disease/vaccine in question, different elements may be emphasised; however, a standardised set of elements is recommended for each FVVA. The FVVA should be developed by an expert group who represent a range of stakeholders, perspectives and geographies and ensure a fair, coherent and evidence-based assessment of vaccine value.

PMID:38400184 | DOI:10.3390/vaccines12020201

Comparative analysis of tuberculin and defined antigen skin tests for detection of bovine tuberculosis in buffaloes (Bubalus bubalis) in Haryana state, India

Latest publications - Fri, 23/02/2024 - 11:00

BMC Vet Res. 2024 Feb 23;20(1):65. doi: 10.1186/s12917-024-03913-3.

ABSTRACT

BACKGROUND: Bovine tuberculosis (bTB) is a chronic disease that results from infection with any member of the Mycobacterium tuberculosis complex. Infected animals are typically diagnosed with tuberculin-based intradermal skin tests according to World Organization of Animal Health which are presently in use. However, tuberculin is not suitable for use in BCG-vaccinated animals due to a high rate of false-positive reactions. Peptide-based defined skin test (DST) antigens have been identified using antigens (ESAT-6, CFP-10 and Rv3615c) which are absent from BCG, but their performance in buffaloes remains unknown. To assess the comparative performance of DST with the tuberculin-based single intradermal test (SIT) and the single intradermal comparative cervical test (SICCT), we screened 543 female buffaloes from 49 organized dairy farms in two districts of Haryana state in India.

RESULTS: We found that 37 (7%), 4 (1%) and 18 (3%) buffaloes were reactors with the SIT, SICCT and DST tests, respectively. Of the 37 SIT reactors, four were positive with SICCT and 12 were positive with the DST. The results show that none of the animals tested positive with all three tests, and 6 DST positive animals were SIT negative. Together, a total of 43 animals were reactors with SIT, DST, or both, and the two assays showed moderate agreement (Cohen's Kappa 0.41; 95% Confidence Interval (CI): 0.23, 0.59). In contrast, only slight agreement (Cohen's Kappa 0.18; 95% CI: 0.02, 0.34) was observed between SIT and SICCT. Using a Bayesian latent class model, we estimated test specificities of 96.5% (95% CI, 92-99%), 99.7% (95% CI: 98-100%) and 99.0% (95% CI: 97-100%) for SIT, SICCT and DST, respectively, but considerably lower sensitivities of 58% (95% CI: 35-87%), 9% (95% CI: 3-21%), and 34% (95% CI: 18-55%) albeit with broad and overlapping credible intervals.

CONCLUSION: Taken together, our investigation suggests that DST has a test specificity comparable with SICCT, and sensitivity intermediate between SIT and SICCT for the identification of buffaloes suspected of tuberculosis. Our study highlights an urgent need for future well-powered trials with detailed necropsy, with immunological and microbiological profiling of reactor and non-reactor animals to better define the underlying factors for the large observed discrepancies in assay performance, particularly between SIT and SICCT.

PMID:38395846 | DOI:10.1186/s12917-024-03913-3

Transdisciplinary approaches to addressing factors that influence antimicrobial use in dairy cattle: A scoping review

Latest publications - Wed, 21/02/2024 - 11:00

Heliyon. 2024 Feb 8;10(4):e25550. doi: 10.1016/j.heliyon.2024.e25550. eCollection 2024 Feb 29.

ABSTRACT

Interest in antimicrobial resistance (AMR) associated with livestock farming is increasing. During the 1990s, 30-40 academic papers a year on the use of antibiotics in dairy farming were indexed on the scientific database PubMed, but this has grown to more than 200 a year in the 2020s. Most (85%) of these papers are published in veterinary or livestock science journals. There has been a corresponding increase in social science interest in why responsible antibiotic stewardship in the livestock sector is so challenging. However, most social science insights are published in journals specific to the lead authors' field(s), missing opportunities for knowledge translation to veterinary and animal science. This threatens to inhibit the transdisciplinary One Health approaches required to tackle the problem. Between 1 June and 31 December 2021, we undertook a scoping review of papers on the use of antibiotics in dairy farming indexed in PubMed, Scopus and Web of Science. Our aim was to identify studies that incorporate social science approaches and methodologies, and to note the main field of the journal in which these studies are published. Papers were most likely to be published in veterinary science, dairy science and/or livestock science journals (61, 29 and 18 respectively out of 127 papers) and were most likely to be concerned with antibiotic use, prescribing practice, and/or diagnosis (94%, 39% and 33% of included papers respectively). Only 27% of papers meeting our inclusion criteria included a qualitative approach to understanding reasons for antibiotic use. Even fewer acknowledged underlying drivers of behaviour, whereas such reasons are frequently highlighted in social science literature. Thus, to address the global health threat from antibiotic resistance, more work is needed to bring together the disparate but equally valid disciplines, methodologies and researchers working on antibiotic use in the livestock sector.

PMID:38379999 | PMC:PMC10877173 | DOI:10.1016/j.heliyon.2024.e25550

Development of an indirect ELISA for the serodiagnosis of canine infection by Onchocerca lupi

Latest publications - Fri, 09/02/2024 - 11:00

Sci Rep. 2024 Feb 9;14(1):3348. doi: 10.1038/s41598-024-53759-w.

ABSTRACT

Onchocerca lupi is a zoonotic filarioid parasite of dogs and cats with widespread distribution. A specific non-invasive diagnostic assay for the detection of O. lupi infections remains unavailable. This study aimed to assess the accuracy, specificity, and sensitivity of an ELISA test designed using nine peptides from two O. lupi proteins. Sera (n = 54) collected from O. lupi infected dogs from endemic areas (Portugal and USA), alongside sera from dogs positive for Dirofilaria immitis, D. repens, Cercopithifilaria bainae, and Acanthocheilonema reconditum (n = 53) from a non-endemic area for O. lupi, as well as from helminth-free dogs (n = 60), were tested. The checkerboard titration method was applied for the optimization of peptide concentrations and conjugate anti-dog dilutions. Sensitivity, specificity, and optimal cut-off values were calculated using ROC curve analysis. All peptides reacted against sera of O. lupi, with no correlation between optic density (OD) values and microfilariae (mfs) loads. Sensitivity and specificity values ranging from 85.45 to 100%, and 88.89% to 100%, respectively, were recorded for all peptides examined, with 100% specificity and sensitivity observed for peptides 40_3, 40_5, 130_3, 120_3 and 40_1, 130_5, respectively. The maximum cut-off value was observed for peptides 40_5 (0.765) and 40_3 (0.708). Testing of sera from dogs positive for other filarioids resulted in lower OD values (up to 1.565) for peptides 40_3 and 40_5 when compared with O. lupi (up to 2.929). The availability of this assay will be of value in epidemiological studies of canine O. lupi infection in both endemic and non-endemic areas, and in assessing the risk for zoonotic transmission.

PMID:38336818 | DOI:10.1038/s41598-024-53759-w

Seroepidemiological and biomolecular survey on <em>Toxoplasma gondii</em> in Sardinian wild boar (<em>Sus scrofa</em>)

Latest publications - Wed, 07/02/2024 - 11:00

Food Waterborne Parasitol. 2024 Jan 26;34:e00222. doi: 10.1016/j.fawpar.2024.e00222. eCollection 2024 Mar.

ABSTRACT

Toxoplasma gondii is a zoonotic parasite able of infecting all warm-blooded animals. Toxoplasmosis is one of the major foodborne diseases globally. The consumption of wild boar (Sus scrofa) meat from recreational hunting has been linked to outbreaks of human toxoplasmosis. The island of Sardinia (Italy) contains a large wild boar population, thus providing an opportunity to assess the distribution of Toxoplasma in this species and the associated risks of transmission to humans. A total of 562 wild boars were screened: heart and meat juice samples were tested for T. gondii DNA via nested-PCR and IgG anti-Toxoplasma by commercial ELISA. Anti-Toxoplasma IgG were detected in 24.6% (138/562) of animals, while 37.2% (209/562) of the heart samples were PCR positive. The prevalence of T. gondii antibodies and DNA highlights the potential role of wild boar as an important reservoir for this parasite. The study suggests that wild boar could play a significant role in spreading the parasite to humans. As wild boar numbers are increasing throughout their range, their potential role in transmitting toxoplasmosis should be communicated to stakeholders, and the impact of different population control methods on disease transmission should be thoroughly assessed to mitigate potential threats effectively.

PMID:38323095 | PMC:PMC10844814 | DOI:10.1016/j.fawpar.2024.e00222

Immunological insights into COVID-19 in Southern Nigeria

Latest publications - Wed, 07/02/2024 - 11:00

Front Immunol. 2024 Jan 23;15:1305586. doi: 10.3389/fimmu.2024.1305586. eCollection 2024.

ABSTRACT

INTRODUCTION: One of the unexpected outcomes of the COVID-19 pandemic was the relatively low levels of morbidity and mortality in Africa compared to the rest of the world. Nigeria, Africa's most populous nation, accounted for less than 0.01% of the global COVID-19 fatalities. The factors responsible for Nigeria's relatively low loss of life due to COVID-19 are unknown. Also, the correlates of protective immunity to SARS-CoV-2 and the impact of pre-existing immunity on the outcome of the COVID-19 pandemic in Africa are yet to be elucidated. Here, we evaluated the natural and vaccine-induced immune responses from vaccinated, non-vaccinated and convalescent individuals in Southern Nigeria throughout the three waves of the COVID-19 pandemic in Nigeria. We also examined the pre-existing immune responses to SARS-CoV-2 from samples collected prior to the COVID-19 pandemic.

METHODS: We used spike RBD and N- IgG antibody ELISA to measure binding antibody responses, SARS-CoV-2 pseudotype assay protocol expressing the spike protein of different variants (D614G, Delta, Beta, Omicron BA1) to measure neutralizing antibody responses and nucleoprotein (N) and spike (S1, S2) direct ex vivo interferon gamma (IFNγ) T cell ELISpot to measure T cell responses.

RESULT: Our study demonstrated a similar magnitude of both binding (N-IgG (74% and 62%), S-RBD IgG (70% and 53%) and neutralizing (D614G (49% and 29%), Delta (56% and 47%), Beta (48% and 24%), Omicron BA1 (41% and 21%)) antibody responses from symptomatic and asymptomatic survivors in Nigeria. A similar magnitude was also seen among vaccinated participants. Interestingly, we revealed the presence of preexisting binding antibodies (N-IgG (60%) and S-RBD IgG (44%)) but no neutralizing antibodies from samples collected prior to the pandemic.

DISCUSSION: These findings revealed that both vaccinated, non-vaccinated and convalescent individuals in Southern Nigeria make similar magnitude of both binding and cross-reactive neutralizing antibody responses. It supported the presence of preexisting binding antibody responses among some Nigerians prior to the COVID-19 pandemic. Lastly, hybrid immunity and heterologous vaccine boosting induced the strongest binding and broadly neutralizing antibody responses compared to vaccine or infection-acquired immunity alone.

PMID:38322252 | PMC:PMC10844438 | DOI:10.3389/fimmu.2024.1305586

Identification of Campylobacter jejuni and Campylobacter coli genes contributing to oxidative stress response using TraDIS analysis

Latest publications - Fri, 02/02/2024 - 11:00

BMC Microbiol. 2024 Feb 1;24(1):46. doi: 10.1186/s12866-024-03201-y.

ABSTRACT

BACKGROUND: Campylobacter jejuni and Campylobacter coli are the major causative agents of bacterial gastroenteritis worldwide and are known obligate microaerophiles. Despite being sensitive to oxygen and its reduction products, both species are readily isolated from animal food products kept under atmospheric conditions where they face high oxygen tension levels.

RESULTS: In this study, Transposon Directed Insertion-site Sequencing (TraDIS) was used to investigate the ability of one C. jejuni strain and two C. coli strains to overcome oxidative stress, using H2O2 to mimic oxidative stress. Genes were identified that were required for oxidative stress resistance for each individual strain but also allowed a comparison across the three strains. Mutations in the perR and ahpC genes were found to increase Campylobacter tolerance to H2O2. The roles of these proteins in oxidative stress were previously known in C. jejuni, but this data indicates that they most likely play a similar role in C. coli. Mutation of czcD decreased Campylobacter tolerance to H2O2. The role of CzcD, which functions as a zinc exporter, has not previously been linked to oxidative stress. The TraDIS data was confirmed using defined deletions of perR and czcD in C. coli 15-537360.

CONCLUSIONS: This is the first study to investigate gene fitness in both C. jejuni and C. coli under oxidative stress conditions and highlights both similar roles for certain genes for both species and highlights other genes that have a role under oxidative stress.

PMID:38302896 | DOI:10.1186/s12866-024-03201-y

Temporal dynamics of the early immune response following Mycobacterium bovis infection of cattle

Latest publications - Wed, 31/01/2024 - 11:00

Sci Rep. 2024 Jan 31;14(1):2600. doi: 10.1038/s41598-024-52314-x.

ABSTRACT

Bovine tuberculosis is an infectious disease of global significance that remains endemic in many countries. Mycobacterium bovis infection in cattle is characterized by a cell-mediated immune response (CMI) that precedes humoral responses, however the timing and trajectories of CMI and antibody responses determined by newer generation assays remain undefined. Here we used defined-antigen interferon-gamma release assays (IGRA) and an eleven-antigen multiplex ELISA (Enferplex TB test) alongside traditional tuberculin-based IGRA and IDEXX M. bovis antibody tests to assess immune trajectories following experimental M. bovis infection of cattle. The results show CMI responses developed as early as two-weeks post-infection, with all infected cattle testing positive three weeks post-infection. Interestingly, 6 of 8 infected animals were serologically positive with the Enferplex TB assay as early as 4 weeks post-infection. As expected, application of the tuberculin skin test enhanced subsequent serological reactivity. Infrequent M. bovis faecal shedding was observed but was uncorrelated with observed immune trajectories. Together, the results show that early antibody responses to M. bovis infection are detectable in some individuals and highlight an urgent need to identify biomarkers that better predict infection outcomes, particularly for application in low-and-middle income countries where test-and-slaughter based control methods are largely unfeasible.

PMID:38297023 | DOI:10.1038/s41598-024-52314-x