Thai DMSC finds 83% Streptococcus suis contamination in Ubon raw pork
Laboratory checks on raw pork from Ubon Ratchathani fresh markets found Streptococcus suis contamination in 35 of 42 samples.
- A study by Thailand's Department of Medical Sciences (DMSC) found that 83.3% of 42 raw pork samples from fresh markets in Ubon Ratchathani province were contaminated with Streptococcus suis.
- The contamination was found to be widespread across 22 fresh markets in the province, with the main strain identified as serotype 2, which is known to cause severe disease in humans.
- The bacteria can be transmitted to people by consuming undercooked pork or through contact with infected animals, potentially causing severe symptoms like meningitis, bloodstream infections, and permanent hearing loss.
- In response to the findings, the DMSC has alerted provincial health authorities to manage the risk and advises the public to avoid eating raw or undercooked pork.
Dr Sarawut Boonsuk, Director-General of the Department of Medical Sciences (DMSC), said Streptococcus suis is a Gram-positive bacterium found in the upper respiratory tract, tonsils, and digestive tract of pigs or other mammals.
People can become infected through contact with diseased animals or animals carrying the pathogen via wounds, abrasions, or the conjunctiva, or by consuming meat, offal, or blood from pigs that have not been properly cooked, or through bacterial contamination.
The infection may cause severe symptoms such as bloodstream infection, meningitis, permanent hearing loss, known as “deafness fever”, and death.
According to data from the antimicrobial resistance surveillance system of the Department of Medical Sciences and its network on Streptococcus suis infections in Thailand from 2022 to 2024, 1,340 cumulative cases were found nationwide, with an increasing trend, reflecting the need for continued disease surveillance and prevention.
The prevalence of Streptococcus suis infection stood at 0.088% in 2022, falling to 0.048% in 2023 before rising to 0.2% in 2024, reflecting a trend in which the infection remains an important public health problem for the country.
Most patients were male, at about 68%, and cases were found most often among people aged 55–74, especially those aged 55–64.
Most laboratory samples came from blood, reflecting the severity of the infection or bloodstream infection.
Most patients also required hospital treatment as inpatients.
The areas with the highest number of patients were Health Region 1 (Upper North), with 288 cases; Health Region 3 (Lower North and Upper Central), with 249 cases; Health Region 8 (Upper Northeast), with 171 cases; Health Region 2 (Lower North), with 136 cases; and Health Region 10 (Eastern Northeast), with 114 cases.
The data came from hospitals that submitted information, representing about 70–75% of the country.
In Ubon Ratchathani province, cases have been found continuously every year, reflecting the characteristics of an endemic disease.
Most recently, in January 2026, the Regional Medical Sciences Center 10, Ubon Ratchathani, under the Department of Medical Sciences, randomly tested and analysed 42 raw pork samples from fresh markets in Ubon Ratchathani province using a highly accurate real-time PCR technique.
Streptococcus suis contamination was found in 35 samples, or 83.3%.
Laboratory results found Streptococcus suis serotype 2 as the main strain, at 37.1%, which causes severe disease in humans.
In terms of distribution from random testing at 22 fresh markets, contamination was found to be widespread, with serotype 2 detected in key areas including municipal fresh markets in Phibun Mangsahan, Si Mueang Mai, Trakan Phuet Phon and Lao Suea Kok districts; Nong Bua and Municipal 5 fresh markets in Mueang district; and fresh markets in Samrong, Nam Khun, Nam Yuen and Thung Si Udom districts.
The bacteria were also found in fresh markets in Sirindhorn, Khong Chiam, Don Mot Daeng, Muang Sam Sip, Warin Chamrap, Khueang Nai, Na Chaluai, Det Udom, Khemarat, Pho Sai, Na Tan, Na Yia, and Buntharik districts, reflecting risks covering almost all areas sampled.
Dr Sarawut also said the Department had sent the analysis results to the Provincial Public Health Office and the Provincial Livestock Office to integrate work on warnings and risk control in the area.
The Department of Medical Sciences will continue working with its network on proactive surveillance in risk areas.
“For the safety of the public, people should buy meat from reliable sources, avoid eating raw pork, raw pig’s blood or pork that is undercooked, and separate utensils used for raw and cooked food,” Dr Sarawut said.
