A dangerous and antibiotic-resistant strain of salmonella found in Danish cattle remains persistent despite a 17-year national eradication plan. New research highlights the hidden economic and health consequences for farmers and public health.
Persistent and Deadly: Salmonella Dublin Still Lurking in Danish Cattle Herds
While most people associate salmonella outbreaks with undercooked poultry, a lesser-known but highly dangerous variant called Salmonella Dublin continues to pose a serious threat in Denmark’s dairy cattle industry. Despite a national eradication program launched in 2008, the disease still lingers in about 5% of Danish cattle herds, down from 20–25% in 2008.
Salmonella Dublin is not just difficult to detect—it is also significantly more lethal to humans than other strains of salmonella. Though human infections are rare, the fatality rate from this strain can be as high as 12%. The bacterium primarily affects cattle, causing pneumonia, blood poisoning, miscarriages, and high mortality in calves. However, humans can contract it through close contact with infected animals or by consuming unpasteurized dairy products and undercooked beef.
A Global Threat with Growing Antibiotic Resistance
Unlike many other salmonella strains, Salmonella Dublin often demonstrates resistance to antibiotics, making treatment more difficult. Beyond its impact on livestock health, this antimicrobial resistance presents a growing concern for global public health.
In comparison to Denmark, prevalence rates are much higher elsewhere. In the United States, around 18% of cattle herds are infected, and in the United Kingdom, the figure can be as high as 60%. As resistance increases worldwide, experts consider this bacterium an emerging international health challenge.
Hidden Economic Burdens for Farmers
In a newly published 10-year study from the University of Copenhagen’s Department of Food and Resource Economics, researchers evaluated the financial costs of Salmonella Dublin across all Danish dairy farms between 2011 and 2021. While the government’s efforts have decreased infection levels, the study reveals that many farmers still lack a strong enough incentive to combat the disease completely.
The research uncovered that infected farms experience significantly higher costs due to increased calf mortality, lower milk production, greater medical expenses, and more frequent veterinary visits. For farms with high levels of infection, additional annual costs average around 84,000 Danish kroner (about $12,000). Even herds with low infection levels report extra costs of about 50,000 kroner ($7,100) per year.
Farmers may not always notice the impact immediately. In many cases, herds carry the infection asymptomatically, which allows the disease—and its financial implications—to progress largely unnoticed.
Current Surveillance Methods May Be Inadequate
Danish authorities currently monitor Salmonella Dublin by testing for antibodies in milk tanks. Farms with levels under a certain threshold are deemed disease-free. Yet, researchers warn that this threshold may not be low enough, as productivity losses are already occurring at milder infection levels that fall within the “safe zone” of current regulations.
This could mean that farms considered uninfected are actually sustaining hidden damage to productivity and animal welfare.
Recommendations for Moving Forward
To eliminate the disease more effectively, researchers suggest that Danish agricultural authorities should reconsider how they incentivize action among farmers. Ideas include offering financial subsidies to farms investing in eradication efforts, penalizing long-term carriers through lower milk prices, and increasing awareness about the hidden economic impacts of the disease.
Moreover, it is recommended that public health officials intensify education regarding Salmonella Dublin’s risks to human health—especially in vulnerable populations such as the elderly, children, and people with weakened immune systems.
Annual reports from the Danish State Serum Institute show that 20–30 cases of human Salmonella Dublin infections are registered each year. While these numbers may seem modest, the high hospitalization rate and fatality risk mean the disease should not be underestimated.
By combining targeted regulation, smarter incentives, and greater awareness, Denmark could take the final steps toward eliminating this costly and dangerous cattle disease.
