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How Thailand got lumpy skin disease under control after 2021

Lumpy skin disease sickened over 627,000 Thai cattle and buffalo in 2021. How biting insects spread it, how vaccination curbed it, and 5 habits for small farms.

Intermediate9 min read

On this page
  1. What lumpy skin disease is
  2. The road to Thailand
  3. March 2021: Roi Et
  4. April to December 2021: the whole country
  5. What turned it around
  6. Lessons for a small farm today
  7. For readers who want more

In early 2021, most Thai cattle farmers had never heard of lumpy skin disease. The Department of Livestock Development (DLD, กรมปศุสัตว์) later counted 627,152 sick animals and 63,757 deaths for 2021 alone, and by December 2022 its map showed the disease in 70 provinces. In September 2024, a DLD veterinarian told a regional WOAH workshop that LSD was "under control through vaccination".

This post follows that story month by month, using the published research and DLD's own reports, and then turns it into a short list of things a small farm can do so the next outbreak, of LSD or anything like it, is caught early.

What lumpy skin disease is

LSD is caused by a poxvirus (genus Capripoxvirus) and mainly affects cattle and water buffalo, according to the World Organisation for Animal Health (WOAH). WOAH lists the signs as fever, firm nodules in the skin (head, neck, udder and elsewhere), swollen lymph nodes, loss of appetite and weight, and lower milk yield. Most animals survive, but the losses are real: weight, milk, fertility and damaged hides.

Two facts matter most for a farmer:

  • It spreads mainly through blood-feeding insects and ticks: biting flies, mosquitoes and ticks. Direct contact plays only a minor role. Over long distances it travels with animal movement and trade (WOAH).
  • It is not a disease of people. WOAH says humans are not at risk, including from milk or meat (WOAH).
Close-up of a cow's back covered in small raised skin nodules
Photo: Monicacomma, CC BY-SA 4.0, Wikimedia Commons (zebu bull in Senegal)

The road to Thailand

LSD was long known in Africa. In Asia, a 2023 overview by Chiang Mai University's Veerasak Punyapornwithaya, presented at WOAH's fourth LSD coordination meeting for South-East Asia, maps how it reached our neighbours: Myanmar and Viet Nam in 2020; Thailand, Laos, Cambodia and Malaysia in 2021; Indonesia in 2022. The first Thai outbreak paper notes that Bangladesh reported it in 2019, before it spread to other countries in the region (Arjkumpa et al., 2022). The same overview says Thailand had the highest number of LSD outbreaks in Asia in 2021, while warning that countries define an "outbreak" differently (a farm, a village, a district), so comparing counts between countries is hard.

March 2021: Roi Et

The first outbreak that was investigated in detail happened in Roi Et, in the northeast. A team from DLD and Chiang Mai University published it in Frontiers in Veterinary Science (Arjkumpa et al., 2022):

  • The outbreak was reported in March 2021, and Thailand reported the first confirmed outbreak to the OIE (now WOAH) on 4 April 2021. (A DLD presentation from December 2021 gives slightly different dates, 5 April for the first report and 9 April for the OIE report, so treat "early April" as the safe summary.)
  • The investigation covered 293 farms in four districts: At Samat, Selaphum, Thung Khao Luang and Phanom Phrai.
  • These were very small herds: 4.3 cattle per farm on average, and 97% of farmers owned fewer than 10 head.
  • 516 of 1,274 cattle fell sick (40.5%) and 15 died (1.2%).
  • No animal in the area had been vaccinated. The authors note that no LSD vaccine was available in Thailand before this outbreak.

The detail I find most useful is about insects. Potential vectors were present on nearly 95% of the farms: mosquitoes on 84% and stable flies on 78%. Meanwhile only 4 of the 293 farms had bought cattle in the two months before the outbreak. In other words, the disease was not mainly walking in on new animals; it was flying from herd to herd.

Farmers did try to protect their animals. Just over half (51.5%) repelled insects with smoke from burning dried grass, about a third (35%) used insect-repellent light bulbs, and only a small share sprayed insecticide (Arjkumpa et al., 2022). The Chiang Mai overview points out that smoke from burning grass only repels insects; it doesn't kill them (Punyapornwithaya, 2023).

One sick cow is enough: a biting fly carries the virus to the next animal. A net over the third cow breaks the chain.
A stable fly resting on a green leaf
Photo: Stu's Images, CC BY-SA 4.0, Wikimedia Commons (stable fly, Stomoxys calcitrans)

April to December 2021: the whole country

From Roi Et the disease spread fast. DLD's month-by-month count of outbreak reports in 2021, from its December 2021 update, shows the shape of the epidemic:

Month (2021) Outbreak reports
April 65
May 488
June 601
July 347
August 149
September 42
October 30
November 24
December (to the 7th) 1

The peak came in June. By early December 2021 the same DLD update counted 68 of 77 provinces, 273,298 farms, 596,506 affected cattle and buffalo and 59,509 deaths. Later figures for the whole year were higher, with 627,152 sick animals (DLD, December 2022). By my arithmetic, that is about one death for every ten sick animals nationally, much higher than the 1.2% seen in Roi Et, but the two numbers come from different kinds of counting, so I wouldn't compare them too closely.

Almost all the cases were in beef cattle. For 2021 to 2022, DLD lists 616,260 beef cattle, 12,341 dairy cattle and 3,681 buffalo, plus 4 gaur (DLD, December 2022). The virus also reached wild animals: DLD reported it in a dead gaur in Prachuap Khiri Khan in June 2021, and later in banteng and a mainland serow (DLD, December 2021).

A young calf in a stall with many skin nodules on its body and legs
Photo: Pavanaja, CC BY-SA 4.0, Wikimedia Commons (calf with lumpy skin disease)

What turned it around

From mid-April 2021, Thailand applied movement restrictions, closed live cattle markets, ran insect control, disinfected farms and stepped up surveillance and public awareness (Punyapornwithaya et al., 2024). The biggest change came with vaccines:

  1. Ring vaccination first. In June 2021 the government started a mass vaccination campaign. The first 360,000 doses of a live attenuated vaccine (LUMPYVAX®, from South Africa) went to animals in high-risk areas around outbreaks (Punyapornwithaya et al., 2024; DLD, 2021). DLD describes this phase as vaccinating susceptible animals within 50 km of outbreaks (DLD, 2022).
  2. Then prevention. A second lot of 5 million doses (MEVAC®, from Egypt) aimed at more than 80% coverage in areas without outbreaks. By December 2021 about 3 million of 5.3 million target animals had been vaccinated, DLD saw no outbreaks in the vaccinated population, and side effects were seen in less than 1% of vaccinated animals (DLD, 2021).
  3. Then a Thai vaccine. DLD started producing its own inactivated LSD vaccine, about 50,000 doses a month in 2022 and roughly 1,000,000 doses a year by 2023, alongside more imported doses. Both cattle and buffalo are vaccinated.
Insects carry LSD to nearby farms, so the first vaccines went to a ring around outbreaks. The ripple slows and stops at the vaccinated farms.

The numbers fell sharply: sick animals went from 627,152 in 2021 to 4,646 in 2022 (DLD, 2022) and 162 in 2023, as reported at the end of November that year (DLD, 2023). A statistical study estimated that cases after the campaign were far lower than they would have been without it, while noting that the other control measures were running at the same time, so vaccination cannot take all the credit (Punyapornwithaya et al., 2024).

It was not cheap. DLD's December 2022 report lists 5,915,230 vaccine doses, treatment on 206,721 farms, insecticide spraying on 227,121 farms, awareness work reaching 434,994 farmers, and 1,236,167,070 baht in compensation (DLD, 2022).

DLD's roadmap aims for no LSD outbreaks in Thailand in 2024–2025 and a self-declaration of freedom from LSD in 2026–2029, with vaccination and public–private cooperation named as the keys (DLD, 2023).

Lessons for a small farm today

The 2021 story points to a few habits that cost little and help a lot. Rules change, so check the details with your district livestock office (ปศุสัตว์อำเภอ).

1. Keep vaccination up to date

In October 2023 DLD's director-general was quoted in Thairath explaining the schedule: the live vaccine once a year, from 1 month of age, and the inactivated vaccine twice a year, from 4 months of age. DLD has also said that young animals got sick again in later years and made calves a priority (DLD, 2023). Keep the vaccination record: you need it to move animals (see point 4).

2. Take insects seriously

The farms in Roi Et almost all had vectors, and a later study of 489 beef herds in three provinces found that herds without insect control had about twice the odds of an outbreak (adjusted odds ratio 2.05) (Arjkumpa et al., 2024). In the same 2023 warning, DLD said LSD spreads more in the rainy season, when mosquitoes, biting midges, flies, horse flies and ticks are common, and suggested nets, repellents on the animals and insecticide spraying in the barn (Thairath, 2023). DLD is also clear that repellents reduce the risk but cannot fully prevent transmission (DLD, 2021), which is why they go together with vaccination, not instead of it.

3. Keep new animals apart

Even if purchases were rare in Roi Et, animal movement is how the disease travels long distances (WOAH), and the Chiang Mai value-chain work found that animal traders played an important role in spread (Punyapornwithaya, 2023). DLD advises keeping newly bought animals apart for at least 14 days and separating any animal with signs (Thairath, 2023).

New animals wait in their own pen for a couple of weeks before they join the herd.

4. Move animals only with the right papers

In 2023 DLD described the rule this way: animals vaccinated at least 30 days and within 1 year before may move with a vaccination certificate; animals that are not vaccinated (or were vaccinated less than 30 days or more than a year ago) may only go to a slaughterhouse within the region (DLD, 2023). The rule had already changed once: in December 2022 DLD described the window for moving animals between provinces as more than 30 and less than 180 days after vaccination. Ask your livestock office for the current version before you sell or buy.

5. Report early

DLD's 2021 report notes that under the Animal Epidemics Act B.E. 2558 (2015), a farmer who finds animals with LSD signs must notify within 12 hours (DLD, 2021). You can report sick or suddenly dead animals to the local livestock officer, the village head or subdistrict office, or through the DLD 4.0 app (Thairath, 2023). An early report means the ring of protection starts closer to your farm, not after the virus has passed it.

For readers who want more

Thai researchers have written a lot about the 2021 epidemic. The Chiang Mai University overview lists ten publications (Punyapornwithaya, 2023), including studies of:

  • the spatio-temporal pattern of outbreaks in dairy farms in the northeast and in the north;
  • forecasting daily new cases and modelling epidemic growth with nationwide data from 2021–2022;
  • the transmission kernel of the virus from Thai outbreak data, which suggests mostly short-distance spread;
  • the molecular characterisation of viruses from northern Thailand in 2021;
  • the impact of LSD on monthly milk production in Khon Kaen dairy farms;
  • an in-house ELISA test for LSD antibodies.

The two field studies I relied on most are open access: the Roi Et outbreak paper and the risk-factor study of 489 herds.

Sources

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