Swine fever outbreak leaves over 1,000 pigs dead in Kiambu

This story has significance for readers across Kenya and beyond.

More than 20 farms in Juja, Thika and Ruiru have been affected by an outbreak of African swine fever (ASF) since mid-May, with about 1,470 pigs reported sick and/or dead and some herds recording mortality of up to 100 per cent, according to the Directorate of Veterinary Services (DVS).

The Kiambu outbreak is the most significant reported anywhere in the country so far, and has exposed a major weakness in Kenya's disease surveillance system.

The government has stepped up measures to contain ASF outbreaks that have continued to hit pig farmers in several parts of the country, with authorities warning of heavy losses if the disease is not brought under control.

The DVS has ordered county veterinary departments to strengthen disease surveillance, improve farm biosecurity, control movement of pigs and activate rapid response teams, following continued circulation of the disease through 2025 and the first half of 2026.

"Significant outbreaks beyond Kiambu have also been reported in Tharaka-Nithi, Busia, Embu, Kakamega, Siaya and Migori counties, resulting in high pig mortalities and substantial economic losses to farmers," the DVS said.

Data from the Kenya Animal Biosurveillance System (Kabs) and the Laboratory Information Management System (Lims) for January to June 2026 show the disease has been reported across several regions, with some outbreaks recording exceptionally high mortality. Tharaka-Nithi recorded 108 cases and 97 deaths between January 5 and 11, a case fatality rate of nearly 90 per cent, and one further case and one death during the April reporting period. Kakamega recorded one case during the January period and a further two cases with no deaths in April. Busia reported one case without a death between March 23 and 29. Embu recorded three cases and one death between May 18 and 24.

Director of Veterinary Services at the State Department for Livestock Development in the Ministry of Agriculture and Livestock Development, Dr Allan Azegele, said in an exclusive interview that ASF is highly infectious and spreads rapidly among pigs, with mortality reaching as high as 70 per cent depending on the strain, age and susceptibility of the animals involved.

"Both adult pigs and young ones can be highly susceptible," Dr Azegele said.

The 2026 report identifies the circulating virus as Genotype IX, a strain research has found to be highly virulent, helping to explain the severe mortality recorded in both the January outbreak in Tharaka-Nithi and the ongoing outbreak in Kiambu.

ASF does not infect humans and is not a public health risk, according to the DVS.

"Pork that has been inspected and certified by an authorised meat inspector is safe for human consumption," Dr Azegele clarified.

However, the disease can devastate pig enterprises by killing entire herds and disrupting trade, leaving farmers with little or no income. Annual economic losses associated with ASF in Kenya are estimated at about USD 7 million (Ksh905.10 million), with smallholder farmers bearing much of the burden. The government is still compiling data on the exact number of pigs lost and the monetary value of losses suffered specifically in the recent Kiambu and Tharaka-Nithi outbreaks. Kenya is estimated to have about 800,000 pigs nationally.

The Director of Veterinary Services said there is currently no effective treatment or commercially available vaccine for the ASF virus strains circulating in Kenya. He attributed this to the virus's ability to change rapidly.

"The virus mutates very fast, which makes it difficult to settle on a vaccine," he said, explaining that a vaccine developed against one strain may become ineffective once the virus changes its surface antigen.

Azegele said farmers should limit the entry of people, animals, vehicles and equipment into pig units.

"New pigs should be obtained only from reputable sources and isolated and observed before being introduced into existing herds. Vehicles entering and leaving farms should be disinfected, while footbaths should be installed near pig houses for workers. Clothing and equipment used around pigs should also be regularly cleaned and disinfected," he added.

Farmers have further been warned against feeding pigs untreated swill or food waste, which can introduce the virus onto farms. Dr Azegele said farmers who use hotel or other food waste should ensure it is properly treated by cooking before feeding it to pigs.

"Cooking the waste with about two per cent soda ash or magadi soda can help neutralise the virus," he said.

The government is also urging farmers to report unusual illness or sudden deaths among pigs immediately to the nearest veterinary office. Where outbreaks occur, farmers and other stakeholders must cooperate with quarantine and animal movement restrictions. Pig carcasses should also be disposed of safely under the guidance of veterinary authorities to prevent further contamination.

"We direct county veterinary departments to intensify inspections at livestock markets, slaughterhouses and retail pork outlets. They will also be required to ensure rapid laboratory confirmation of suspected cases, trace animal movements and train farmers to recognise symptoms of the disease," the Director of Veterinary Services said, noting that the response is being implemented under the national African Swine Fever Control Strategy and the ASF Risk Communication and Community Engagement Strategy, both of which have been distributed to county veterinary directors.

Azegele said ASF has become increasingly frequent in Kenya, particularly in counties with significant pig production. He noted the disease was initially known to occur in cycles of about 10 years, but the emergence of different variants has changed that pattern, with outbreaks now occurring more frequently.

Adding to the concern, the 2026 surveillance findings raise the possibility of pigs that carry the virus without showing signs of illness. Research found ASF virus in internal organ tissues of 15.9 per cent of apparently healthy pigs sampled along the Kenya-Uganda border. Such asymptomatic carriers could silently maintain and spread the virus, making detection more difficult and increasing the risk of fresh outbreaks when pigs are exposed to stress, a risk that is particularly significant in border areas such as Busia.

The government has developed an Animal Identification and Traceability System (Anitrac) that will allow authorities to identify individual animals and their owners. Dr Azegele said the digital system, which seeks to address the country's animal data gap, will help strengthen measures to combat disease outbreaks such as African swine fever. Once implemented, farmers will be able to access information about their animals and undertake transactions through the platform, which will also record an animal's history, including illnesses, ownership and movements, from birth to slaughter, export or another final destination.

Veterinary authorities have been urged to intensify surveillance in high-risk areas, particularly Kiambu, Tharaka-Nithi and Embu, as well as border regions. Farmer education on biosecurity, early reporting and the risks posed by healthy carrier pigs is also being prioritised.

Reporting originally appeared via Nation Africa. Read the full source for additional context.