Salmonella Heidelberg Persists

Salmonella Heidelberg is a multi-drug-resistant Salmonella species that can cause severe illness in calves and humans, and is transmittable between the two. ( Maureen Hanson )

Veterinary and human epidemiologists continue to be concerned about periodic occurrences of Salmonella Heidelberg. At the 2018 Dairy Calf and Heifer Association Annual Conference, USDA Veterinary Epidemiologist Jason Lombard updated attendees on the latest outbreak of the disease, which caused infections in both humans and dairy calves.

Lombard said the U.S. Centers for Disease Control and Prevention (CDC) recently released a report on the multi-state outbreak. In total, 56 people from 15 states were infected with 17 hospitalizations and, fortunately, no deaths. About a third of the cases were children younger than 5 years old.

About two-thirds of the affected patients reported contact with dairy calves or other cattle. Some of the ill people interviewed reported that they became sick after their calves became sick or died.

Follow-up investigation on the affected case farms showed that all of the farms had purchased cattle from outside sources. A USDA Info Sheet on Salmonella Heidelberg in dairy calves notes that calves acquired from dealers, sale barns, auctions or markets are more likely to succumb to Salmonella Heidelberg, due to transport stress and exposure to other animals that may be shedding the organism.

“Farms whose calves traveled more than 50 miles were at greater risk,” noted Lombard. He said herds that acquire calves from outside sources should purchase them from trusted suppliers; minimize travel distance; confirm passive transfer of immunity (IgG>10g/L); and ensure that transport vehicles are washed and disinfected between groups of calves.

Lombard shared that fellow veterinarian Don Sockett with the University of Wisconsin Veterinary Diagnostic Laboratory has noted Salmonella Heidelberg is one of the most brutal calf diseases he has ever seen. Sockett has investigated many on-farm cases of the disease, and told him calves can die within 4 to 8 hours of clinical disease signs, with some dying before showing any signs at all. “This underscores the importance of hygienic on-farm practices to protect human health,” said Lombard.

The CDC offers the following advice to prevent human contraction of zoonotic diseases like Salmonella Heidelberg from animals:

  • Always wash hands thoroughly with soap and water right after touching livestock, equipment for animals, or anything in the area where animals live and roam.
    • This is especially important to do before preparing or consuming food or drink for yourself or others.
    • Adults should supervise hand washing for young children.
    • Use hand sanitizer if soap and water are not available right away.
  • Use dedicated shoes, work gloves, and clothing that you only use when working with livestock. Keep these items outside of your home.
    • Do not eat or drink in the areas where livestock live and roam.
    • Do not allow toys, pacifiers, spill-proof cups, baby bottles, strollers, or similar items in livestock areas.
    • Wash hands after removing any clothes and shoes you wore while working with livestock.
  • Work with your veterinarian to keep your livestock healthy.
    • If you think your livestock are sick, talk to your veterinarian as soon as possible and take extra care to wash your hands after working with the animals and use separate clothes when caring for them.
    • Children, adults over age 65, and people with compromised immune systems should limit their contact with sick animals.