WOAH Biological Standards Commission decides to relaunch a global call for new tuberculin candidates after extensive international trials

Following a decade of international studies, the WOAH Biological Standards Commission, supported by an ad hoc group of experts, has concluded that the proposed replacement candidates for the International Standard for Bovine Tuberculin do not meet the required potency levels. It will now relaunch a global call for new candidates’ materials. 

What is the International Standard for Bovine Tuberculin? 

The International Standard Bovine Tuberculin (ISBT) is a biological reference material derived from Mycobacterium bovis strain AN5. Established nearly three decades ago, it defines a standardised protein concentration that serves as the global benchmark for tuberculin potency testing.  

ISBT is used worldwide in bovine tuberculosis control programmes for screening cattle. All commercial bovine tuberculin preparations must be calibrated against this standard. 

The science behind tuberculin testing 

Tuberculin testing exploits the immune system’s memory of infection. When Mycobacterium tuberculosis complex organisms infect cattle, the animal’s immune system develops a hypersensitivity response to specific bacterial proteins. The tuberculin skin test capitalises on this biological activity by injecting purified protein derivative (PPD) intradermally and measuring the resulting immune response as an increase in skin thickness. This delayed hypersensitivity reaction, measured 72 hours post-injection, indicates prior exposure to tuberculosis. 

A decade-long effort to replace the standard 

The current ISBT, established in 1986, has been in limited supply since 2015. In response, WOAH’s Biological Standards Commission, supported by an ad hoc group of mammalian tuberculosis reference laboratory experts, has coordinated experiments with multiple laboratories, research institutes and tuberculin manufacturers across continents to identify a suitable replacement. 

Key findings  

Two candidates were initially shortlisted in 2017. Following further evaluation, only one (Candidate B) progressed to international collaborative trials conducted between 2018 and 2025.  

However, the latest assays revealed persistent potency shortfalls: 

• Potency levels (18,000–19,116 IU/mg) remained well below the required minimum of 32,000 IU/mg. 

• Multiple laboratories confirmed inconsistent results despite protocol refinements. 

• High assay variability and weak dose-response relationships hindered reliable potency determination. 

Final trials in November 2025 confirmed that Candidate B does not meet the criteria to replace ISBT. 

Future directions 

The Biological Standards Commission acknowledged that PPD is a complex biological substance having many specific and non-specific proteins. They emphasised that accepting a lower potency international standard would compromise the comparability of global tuberculin standardisation across laboratories and batches.  

The Commission therefore decided to: 

• relaunch a global call for new tuberculin candidates. 

• support the development of alternative approaches for PPD-based tests such as the Molecularly Defined Tuberculins (MDTs) which use specific peptides as a long-term alternative to traditional PPD-based assays. 

While promising, MDTs require further field validation across different epidemiological settings before they can replace current methods.

More information 

The full meeting report, including detailed methodology and statistical analyses, is available on the WOAH website: 

WOAH Ad hoc Group on Replacement of the International Standard for Bovine Tuberculin. Report 2015-2025.

Ad hoc Groups – WOAH – World Organisation for Animal Health 

Biological Standards Commission – WOAH – World Organisation for Animal Health 

Contact: [email protected] 

Field evaluation and post-vaccination monitoring for informed decision-making

The right evidence, at the right moment, can guide better decisions. 

As African swine fever (ASF) continues to affect pig production, animal health systems and safe trade worldwide, WOAH has published new guidelines to support evidence-based vaccine use. The Guidelines for African swine fever vaccines: field evaluation and post-vaccination monitoring provide practical guidance to help Members implement international standards and mitigate risks associated with substandard vaccines. 

Developed with experts from The Pirbright Institute and the Centre for Applied One Health Research and Policy Advice at City University of Hong Kong, the guidelines are now available and provide a practical, field-oriented reference for Veterinary Services, competent authorities and other stakeholders involved in vaccine deployment. 

Supporting evidence-based decisions in the field 

ASF vaccination is rapidly evolving. While vaccine candidates are under development and some live attenuated virus vaccines have received regulatory approval in certain countries, WOAH emphasises that only high-quality vaccines manufactured according to international standards should be used. Vaccination decisions must be grounded in reliable evidence and adapted to local epidemiological conditions. The guidelines support Members in generating and assessing this evidence, covering the design, implementation and evaluation of field studies, as well as the benefit–risk assessment that should precede any national or regional vaccination programme. Practical tools, including sample size calculators and recording form templates, are included to help users apply the guidance directly on the ground. 

From field trials to post-vaccination monitoring 

Running a field trial well requires getting many things right at once: clear case definitions, appropriate study designs, rigorous randomisation, consistent data collection and validated laboratory testing. The guidelines walk users through each of these elements, with worked examples where possible, to ensure that field evaluations generate evidence that is both reliable and usable for decision-making. 

Post-vaccination monitoring is equally important. The guidelines cover the systematic tracking of vaccine effectiveness under real-world conditions, alongside pharmacovigilance to detect side effects or adverse events. A dedicated three-step framework is provided to help countries set up and sustain monitoring systems, from establishing expected side effects and reporting channels to periodically evaluating and revising the programme. Genomic surveillance, including whole genome sequencing where feasible, is also recommended to detect potential reversion to virulence or recombination events over time. 

Vaccination as one tool among many 

These guidelines make clear that vaccination is not a standalone solution. It must be integrated  into comprehensive ASF prevention and control strategies, alongside biosecurity, surveillance and movement controls, tailored to each Member. 

Bringing technical guidance closer to Members 

Aligned with WOAH’s commitment to supporting Members in building robust animal health systems, the guidelines are designed to be adapted rather than applied rigidly. Countries with sufficient resources are encouraged to conduct their own field trials. Others can draw on data from countries with comparable production systems, with WOAH facilitating connections to relevant Reference Laboratories and Collaborating Centres. Transparency and data sharing are highlighted throughout, in keeping with the principles of the Terrestrial Animal Health Code. 

ASF is a transboundary disease, what happens in one country affects its neighbours. That is why the evidence generated through field trials needs to be shared, not kept in silos.  

Upcoming webinar 

To support the practical use of these guidelines, WOAH will host a webinar on 30 June 2026, bringing together the authors and selected Members to discuss the application of this resource. 

More information 

Guidelines for African swine fever vaccines: field evaluation and post-vaccination monitoring 

Contact: [email protected]

Authors: A. Bouma, H.A. Lim, T.J.D. van Riet, H.I.J. Roest

Since 2021, high pathogenicity of avian influenza virus H5N1 (HPAI H5N1) has spread worldwide.  It is present in many countries, causing widespread infections in poultry that are often controlled through large-scale culling. The virus is also established in wild bird populations and has led to infections in several mammal species. While human infections remain rare, the risk of a broader public health event, such as a pandemic, cannot be ignored. Reducing virus spread is therefore a priority for both animal and human health. Vaccination could be one of the tools to support this goal and should not be hampered by unjustified trade barriers.

Global situation of HPAI

HPAI H5N1 continues to cause recurring outbreaks in poultry and mammals, with often devastating impacts on the poultry sector and wild animal populations. Control measures rely largely on culling infected flocks, leading to the loss of millions of birds. This approach warrants reconsideration, particularly given the sustained circulation of the virus in wild bird populations. More sustainable, long-term strategies are needed, and vaccination could serve as a valuable additional tool to achieve this goal.

Vaccination, animal health and safe trade

In 2023, the WOAH World Assembly of Delegates adopted Resolution No. 28, recognising vaccination as a complementary disease control tool. WOAH international standards stipulate that vaccination use does not affect a country’s HPAI-free status, provided surveillance demonstrates the absence of infection.

Despite this progress, several challenges remain. Vaccination programmes are currently applied in only a limited number of at-risk countries. Although more countries are considering vaccination, concerns about vaccination and surveillance costs, product value and potential impacts on international trade continue to limit uptake, especially in exporting countries. While some trade barriers are justified, others appear disproportionate and need further discussion.

To address these challenges, the Netherlands set up an international working group on HPAI vaccination and trade. Together with Canada, the European Commission, France, the United Kingdom, the United States of America and WOAH, the Netherlands organised a meeting of this working group last January. Participants agreed to work together to make HPAI vaccination feasible in the near future, providing necessary assurances to allow safe trade.  

Key issues to be addressed

The working group underlined the need to develop and recognise minimum requirements that would facilitate international trade in products from vaccinated poultry and eliminate unjustified trade barriers. The group also noted that agreements with respect to vaccination and trade should be aligned with existing international standards, such as zoning, and should include appropriate surveillance and control measures that support virus control while maintaining trade confidence.

Next steps

A side event will be organised during the WOAH General Session in May. The international working group will present progress to date and outline planned activities. The focus will be on improving understanding of vaccination performance and exploring the development of minimum, widely supported surveillance programme requirements to demonstrate the absence of infection and facilitate trade in products from vaccinated poultry.

In addition, WOAH will develop guidelines for surveillance of HPAI in vaccinated poultry population, with the aim of supporting disease status recognition and safe trade.

Members interested in supporting future vaccination efforts are encouraged to express their interest.

Looking ahead

The goal is to move towards a more sustainable poultry sector that prioritises animal health and welfare, while also protecting public health and the environment.

WOAH has launched the Guidelines Mitigating Disease Transmission Risk at the Wildlife–Livestock Interface to Facilitate Safe Trade, providing Veterinary Services with practical guidance to manage disease transmission risks where wildlife and livestock interact. The guidelines respond directly to Members’ needs to control transboundary animal diseases while maintaining continuity of safe national and international trade.

Why Did WOAH Develop These Guidelines?

Transboundary animal diseases (TADs), such as African swine fever (ASF), avian influenza (AI) and foot and mouth disease (FMD) continue to spread worldwide, with serious consequences for animal health, trade and livelihoods. In many countries where these diseases are endemic, infections can pass between wild and domestic animals, sustaining infection transmission cycles that are difficult to control because of the complex factors and risk pathways involved.

Importantly, for some diseases, WOAH standards allow the recognition of animal health status in effectively separated subpopulations and require that Members do not ban international livestock trade on the sole ground of disease occurrence in wildlife.

In this context, Members have requested WOAH guidance on managing risk at wildlife–livestock interface (WLI) for disease control purposes, while preserving the animal health status of domestic subpopulations for business continuity.

How Were the Guidelines Developed?

In 2024, WOAH launched a consultancy to develop technical guidelines addressing disease management at the wildlife–livestock interface.

The guidelines were authored by Prof. Christian Gortázar, Dr Joaquín Vicente and Dr Ursula Höfle from the Instituto de Investigación en Recursos Cinegéticos (IREC), Universidad de Castilla-La Mancha and the Spanish National Research Council (CSIC), Spain—an internationally recognised team with extensive expertise in this field.

In January 2025, the first draft underwent peer review by a WOAH ad hoc Group, which provided expert opinions and recommendations while ensuring that regional perspectives were considered. The WOAH Scientific Commission for Animal Diseases (SCAD) also reviewed the draft to confirm scientific soundness and alignment with WOAH international standards. Additionally, the WOAH Working Group on Wildlife  was consulted to ensure wildlife-related aspects were accurately addressed.

Following these reviews and revisions, the guidelines were officially published on the WOAH website in December 2025.

How Should the Guidelines Be Used?

The guidelines offer practical approaches for managing disease spillover risk between wildlife and livestock across a wide range of farming systems. They propose a structured methodology enabling Veterinary Services to manage WLI scenarios through customised risk mitigation programmes tailored to local conditions and needs.

Rather than offering prescriptive solutions, the guidelines present a flexible framework for addressing wildlife–livestock interfaces. Case studies and field examples illustrate how risk mitigation measures can be adapted to different epidemiological contexts.

Effective disease risk management must be tailored to local realities, taking into account geography, production systems, wildlife species and the target disease. All interventions should align with WOAH international standards and relevant national regulations.

Their effective use requires a solid background in veterinary sciences, particularly disease epidemiology, and benefits from knowledge of wildlife ecology. A clear understanding of the specific WLI scenario, farming practices and key risk pathways is essential for successful implementation.

WOAH encourages Members to make use of the guidelines to better implement the provisions outlined in the international standards and to share their experiences with the Organisation.

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Resources

Recording of the launch webinar on 15 January 2026: Webinar: Launch of Guidelines ‘Mitigating Disease Transmission Risk at the Wildlife – Livestock Interface to Facilitate Safe Trade’ – WOAH – World Organisation for Animal Health

Authors: Samuel A. Anzaku, Zainab Abdulkareem, Maureen Kajo, Babatunde Akinola, Ibrahim Dauda, Daniel Chinemerem, Mwapu D. Ndahi

To reduce reliance on antimicrobials and promote good husbandry practices in animal farming, farmers in Nigeria were sensitised on antimicrobial resistance (AMR), its drivers, consequences and mitigation strategies. The awareness activities focused on the responsible use of antibiotics, antivirals, antifungals and anthelmintics, and encouraged the adoption of WOAH’s technical guidance on controlling anthelmintic resistance in grazing. These efforts support WOAH’s global objectives to strengthen AMR surveillance and promote prudent antimicrobial use in the animal sector. Baseline assessments were conducted to evaluate farmers’ knowledge, attitudes and practices. The workshops were organised by WOAH Focal Points on Veterinary Products at the Federal Ministry of Livestock Development (FMLD), in collaboration with Management Sciences for Health (MSH).

Baseline Assessment of Farmer Practices

A baseline survey was conducted to evaluate farmers’ knowledge, attitudes and practices (KAP) regarding AMR. Using a questionnaire developed from published literature and deployed via KoboToolbox, responses were collected from  poultry and fish farmers.

Key findings revealed:

• – 81.48% of farmers had over 18 months of experience.
• – 78% experienced disease incidents on their farms.
• – 90% used antimicrobials without a prescription.
• – While most were aware of biosecurity, only half had received training.
• – 63% maintained records of drug use.

These results highlight the widespread use of antibiotics and the need for structured training and improved biosecurity implementation. Record-keeping practices offer a foundation for better AMR monitoring.

Farmer Workshops on AMR and Alternatives

Workshops, held in Kano, Anambra, Akwa Ibom and Kwara States, engaged 200 poultry and fish farmers. Each session raised awareness of AMR and promoted sustainable farming practices.

Topics presented included:

• – Introduction to AMR and its impact across microorganisms (bacteria, viruses, fungi and parasites).
• – Drivers and consequences of AMR.
• – Alternatives to antimicrobials, including biosecurity, vaccination and use of pre/probiotics.

Furthermore, a team of experts and farmers prepared social and behavioural change communication materials. These materials were distributed for further training within their communities.

Participatory Training and Reporting

A total of 450 stakeholders in the poultry and aquaculture sectors were reached through participatory and integrated communication models. Approaches included presentations on AMR, group work, experience sharing and Q&A sessions. Additionally, farmers were trained on the use of KoboToolbox for reporting antimicrobial use, enhancing local data collection and surveillance.

The intention is to focus on the WOAH document on anthelmintics this year and prepare a follow-up report next year.

More information

• – Responsible and prudent use of anthelmintic chemicals to help control anthelmintic resistance in grazing livestock species
• – Recommendation of the Focal Points Seminar for English Speaking Africa

Main photo © Oluyinka Alawode