When a country detects highly pathogenic avian influenza in a commercial poultry flock, or foot and mouth disease in cattle, the consequences extend far beyond the affected farm. Export markets close within hours. Vaccination policies shift. Surveillance budgets expand. Trade restrictions can persist for years.

The World Organisation for Animal Health (WOAH) collects notifiable disease event data from its 183 member countries through the World Animal Health Information System (WAHIS). This article analyzes 6,650 outbreak events in the WAHIS database (latest extract, covering events primarily from 2024–2026) to show which diseases are driving the most disruption, which countries are most affected, and what the trend means for veterinary practice and global animal health. Every number below is computed directly from the WOAH WAHIS outbreak event records (analysis run date: 2026-06-10).

Three things these numbers do not mean

1. Events are not individual animal cases. Each WAHIS event may represent a single outbreak on one farm or a cluster of cases across a region. The count reflects reporting events, not the total number of sick or dead animals.
2. Reporting reflects capacity, not just disease burden. Countries with stronger veterinary infrastructure and surveillance systems detect and report more events. An absence of reports from a country does not mean disease is absent — it may mean surveillance is limited.
3. Ongoing events are not necessarily escalating. An event listed as "On-going" has not yet been officially closed; it may be under control but awaiting the surveillance period required for WOAH to accept resolution.

The top diseases by event count

Two diseases dominate: HPAI in non-poultry species (primarily wild birds) accounts for nearly one-third of all events, and when combined with HPAI in poultry, avian influenza represents 38% of the entire dataset. Foot and mouth disease and bluetongue are tied at 665 events each — both diseases that trigger immediate trade restrictions and require WOAH notification.

HPAI subtypes

Among HPAI events where subtype information is available:

H5N1 is the overwhelming subtype — consistent with the global clade 2.3.4.4b expansion that has been underway since 2020 and has reached every continent except Australia. H5N5 and H5N2 represent reassortant variants that have emerged more recently.

The countries most affected

The United Kingdom leads with 1,330 events — more than any other country. This is driven primarily by HPAI (the UK reported extensively on wild-bird HPAI events) and bluetongue (665 events, all ongoing, reflecting the major BTV-3 epizootic that began in 2023 and continues into 2026). Norway's 665 events are almost entirely bluetongue.

Disease-country connections

The data reveals sharp geographic clustering:

• Bluetongue is concentrated in the UK (all 665 UK events) — a single large epizootic.
• Foot and mouth disease is reported from Eswatini (399), Cyprus (133), and Libya (133) — all countries where FMD-free status has been suspended.
• New World screwworm is concentrated in Mexico (399 events) — the ongoing outbreak that prompted USDA APHIS to restrict imports and issue emergency use authorizations.
• Rabies is reported from Germany, Moldova, and Armenia — reflecting ongoing wildlife reservoir surveillance.

The time trend

The jump from 399 events in 2024 to 3,325 in 2025 reflects both a genuine increase in disease activity (particularly the HPAI panzootic and bluetongue expansion in Europe) and improved surveillance and reporting. The high proportion of ongoing events — 82% across the dataset — indicates that most outbreaks in this period have not yet been officially resolved.

Why this matters for trade

WOAH-recognized disease status is the foundation of international animal and animal-product trade. When a country loses its WOAH-recognized "free" status for a disease, trading partners impose import restrictions — sometimes within hours.

Recent examples visible in this data:

• Greece lost FMD-free status in March 2026 after an outbreak on Lesvos.
• Cyprus lost FMD-free status in February 2026 after outbreaks in Larnaca.
• Botswana had multiple FMD-free zones suspended between January and March 2026.
• The UK's bluetongue epizootic has affected livestock trade across the English Channel.

USDA APHIS maintains a Region Health Status list that catalogs which countries face import restrictions based on their disease status. As of April 2026, more than 70 countries face avian-influenza-related restrictions, and multiple countries have FMD restrictions in effect.

The reporting landscape

Events in this dataset come through two report types:

Most entries are follow-up reports — updates to previously notified events. The initial detection triggers an immediate notification, and subsequent reports track the outbreak's evolution. The high FUR-to-IN ratio reflects the fact that many of these diseases require prolonged surveillance and control efforts.

The reason for reporting also reveals patterns:

The most common reason — recurrence of a previously eradicated disease — highlights a structural challenge: diseases that were once controlled are returning, often through wildlife reservoirs, trade-related introductions, or vector expansion driven by climate change.

What this means for veterinary practice

For food-animal practitioners: The HPAI and bluetongue situations are not abstract — they directly affect client herds and flocks through movement restrictions, mandatory vaccination programs, surveillance testing, and culling orders. Staying current on the WOAH and national veterinary authority notifications for your region is now a routine professional requirement.

For companion-animal practitioners: Rabies remains endemic in multiple European countries. The New World screwworm situation in Mexico prompted the FDA to issue Emergency Use Authorizations for animal treatments in 2025–2026. Disease emergence is not only a livestock issue.

For practice owners managing imports and exports: Clients involved in livestock trade, horse movement, or poultry production need veterinary support for health certification, pre-movement testing, and navigating the trade restrictions that follow disease detections. This is a growing service line.

Sources

• WOAH (World Organisation for Animal Health). WAHIS — World Animal Health Information System. https://wahis.woah.org/
• WOAH. "Animal Health Situation Worldwide — 2025." Technical item, 93rd General Session, May 2026. https://www.woah.org/app/uploads/2026/04/gs93-2026-wd-tech-02-animal-health-situation-en-2.pdf
• WOAH. Foot and mouth disease — disease page. https://www.woah.org/en/disease/foot-and-mouth-disease
• WOAH. Avian influenza — disease page. https://www.woah.org/en/disease/avian-influenza
• FAO. Global AIV with Zoonotic Potential — situation updates. https://www.fao.org/animal-health/situation-updates/global-aiv-with-zoonotic-potential/en
• USDA APHIS. Region Health Status — Animals. https://www.aphis.usda.gov/livestock-poultry-disease/animal-health-status