Cause: Salmonella Typhimurium or Salmonella Enteritidis
Transmission: Direct contact with contaminated material such as faeces.
Geographic distribution: All of Scandinavia
Seasonal occurrence: All year
Salmonella occasionally can be found in both sick and healthy hedgehogs. Proper hand hygiene following contact with hedgehogs is important because salmonella can also infect humans (zoonosis).
Through post-mortem examination and bacterial sampling of hedgehogs, salmonella has been found in relatively few animals in Sweden, with the exception of the counties of southwest Skåne and Gotland.
There are a higher number of human cases of S. Typhimurium DT1 in Skåne compared to the rest of the country. Children under six years of age are overrepresented and most cases were reported during late summer/autumn.
A study conducted in 2008-2009 demonstrated the same serotype in approximately 11% of hedgehogs sampled in the same area. This study was performed in collaboration with the Infectious Diseases Unit in Skåne and the former Swedish Institute for Communicable Disease Control (SMI), now the Public Health Agency of Sweden.
In the autumn of 2013 on Gotland, a number of rehabilitated young hedgehogs died from a generalized infection with Salmonella Enteritidis. Other hedgehogs admitted for rehabilitation carried S. Enteritidis in their intestines. Similar numbers of hedgehogs have died in 2014 and a project is ongoing to investigate the occurrence of salmonella in hedgehogs on Gotland.
Larger outbreaks of salmonella in hedgehogs have been seen locally in Norway and Finland. In Norway, two different types of salmonella have been detected in hedgehogs; S. Typhimurium DT1 and S. Typhimurium DT42. In humans, a major outbreak in 1996, as well as annual smaller outbreaks and sporadic cases have been reported. Hedgehogs were considered the likely source of infection.
S. Typhimurium DT1 has also been detected in hedgehogs in Finland. A Finnish report published in 2003 concluded that hedgehogs and small birds (where this phage type was also found) cannot be excluded as reservoirs from which infection can spread to humans and animals. S. Enteritidis has also been reported in hedgehogs in Denmark and England, and in England it is believed to be endemic in the hedgehog population.
Salmonella infections in hedgehogs usually cause intestinal inflammation with diarrhoea, dehydration, emaciation and finally death, but hedgehogs can also carry salmonella without being ill.
It is important to remember that salmonella can infect humans and cause disease, therefore you should be careful whenever feeding, cleaning food bowls or handling sick or dead hedgehogs. Careful hand hygiene through thorough hand washing with soap and water is important to avoid infection.