Zoonoses That May Be Acquired From Rats: England and Wales

Data on trends in leptospirosis can be found in the UK Zoonoses Reports:  http://archive.defra.gov.uk/foodfarm/farmanimal/diseases/atoz/zoonoses/reports.htm

Rat bite fever (Streptobacillus moniliformis)

Rat bite fever is a rare human disease that may be acquired from infected rat bites or from handling infected animals. Since 2000 there have been one to two cases reported each year; some are believed to have been acquired overseas. Outbreaks of 'streptobacillary fever' may occur following the consumption of milk or water contaminated by infected rats. One such incident occurred in 1983 when 304 pupils and staff at a boarding school were affected; four cases were confirmed by isolation of the organism. Investigation revealed that part of the private water supply could have been contaminated by rats.
More information about rat bite fever

Hantavirus

European hantaviruses cause acute haemorrhagic fever with renal syndrome and are transmitted to man via the urine, droppings or saliva of infected rodents. Although there is some serological evidence of human infection, there have been few reports of acute infection acquired in the UK, and these have generally occurred sporadically. Infection in imported laboratory rats was the source of an outbreak of four cases in laboratory workers in England in 1977. Infections may also be acquired overseas, as the different hantaviruses have varied geographical distributions (but all are associated with a rodent reservoir). Exposure to rodent excreta may occur at rubbish dumps/tips, especially if these are not properly managed with regard to rodent populations.
More information about hantavirus.

RATS ARE UNLIKELY TO BE IMPORTANT SOURCES OF INFECTION FOR HUMANS FOR THE FOLLOWING ZOONOSES

Salmonella spp

Infected rats are unlikely to be an important source of human infection. For most cases of human salmonellosis recorded at the HPA the source of infection is not known; statistics on rat-borne infections are not therefore available.

Cryptosporidium spp

Infected rats are unlikely to be an important source of human infection; for most cases of Cryptosporidium sp the source of infection is not stated.

Trichophyton spp

Ringworm (dermatophytosis) is a common fungal skin disease of mammals, with a worldwide distribution. There are no statistics available in England and Wales on the number of human infections that may have been acquired following contact with infected rats.

Pasteurella spp

Human pasteurellosis is usually acquired following animal bites or sometimes scratches, especially from domestic pets such as dogs and to a lesser extent, cats. It is a common wound infection occasionally resulting in systemic symptoms. Pasteurella multocida is a commonly reported zoonotic infection, usually resulting from dog or cat bites or scratches. Pasteurella pneumotropica is a cause of pasteurellosis in laboratory rodents and the organism is carried in the mucous membranes of the oropharynx. In 2009 there were 456 laboratory confirmed cases of pasteurellosis reported. Few cases of pasteurellosis are known to have been acquired from rats.

Yersinia spp

 Yersiniosis is a common infection of many animals, including rats, but some of the rodent serotypes may not affect humans. The disease in humans is caused mostly by Yersinia enterocolitica. Transmission usually occurs by ingestion of contaminated food or water, less commonly by contact with infected animals, and rarely from person-to-person spread via the faecal-oral route. In England and Wales, 47 cases of yersinosis were recorded in 2009, of which 40 were typed as Y. enterocolitica.

Plague is caused by Yersinia pestis, and is normally acquired via the bite of an infected rat flea. Plague no longer occurs naturally in the UK (the last cases were in 1918), however, it is still found in many countries around the world, particularly in Africa and Asia, but also the USA.

Hymenolepis sp

Hymenolepiasis is a worldwide but common, mild tapeworm infection. Human infections with the species found in rats, Hymenolepis diminuta, are uncommon. Between 1995 and 2006, CfI received 11 reports of human infection, all are believed to have been acquired overseas, mainly in the Indian Sub-Continent.

Q fever

Since 1990, no laboratory reports received by CDSC have indicated rats as a possible source of infection, although a number of patients have reported working in agricultural and other environments where rats could be present.

Toxoplasmosis

No reports received since 1990 have indicated rats as a possible source of infection.

Murine Typhus (flea-borne typhus fever)

Murine typhus (caused by infection with Rickettsia typhi) occurs worldwide and is transmitted to humans by rat fleas. It is found in areas where humans and rats occupy the same buildings. It does not occur in the UK; any reported cases are likely to have been acquired overseas. Flea-infested rats can be found throughout the year in humid tropical environments, but in temperate regions are most common during the warm summer months. Travellers who visit rat-infested buildings and homes, especially in estuarine or riverine environments, can be at risk for exposure to the agent of murine typhus. A small number of rickettsial infections, usually rickettsial spotted fevers, are reported annually, all are believed to have been acquired overseas.

Other infections

There are other infections or diseases that may be transmitted to man either directly (ie. via bites) or indirectly (ie. via ticks and fleas) from rats but which are not endemic in this country. These include tularemia (Francisella tularensis), rabies, and plague (Yersinia pestis).

Last reviewed: 20 May 2011