Tularemia

Tularemia is a bacterial disease which has various modes of transmission to humans. It can be a vector-borne disease via an infected tick, deer fly or mosquito. It can also be transmitted through handling infected animals (rodents, hares, or rabbits), or via inhalation or contaminated water.

Tularemia goes by several names related to the carrier, including “rabbit fever” and “water-rat trapper’s disease”. The bacterial infection is Francisella tularensis, and it is extremely resistant to environmental stress, surviving in soil and water and animal carcasses for long periods of time and at low temperatures.

Person to person transmission hasn’t been reported.

Outbreaks of tularemia have been reported in Europe (Sweden, Germany, Finland, Czech Republic, Kosovo, Bulgaria, Poland, Belarus, Spain, Turkey, Norway, Finland). More than 800 cases annually are notified. The highest rates are in Sweden and Finland.

Cases transmitted by ticks and mosquitoes are more likely to be reported in the warmer of the year (spring, summer, and autumn), while those transmitted by water are more likely in the winter.

About 200 cases are reported annually in the USA. The number of cases have dropped from the 1950’s when the numbers exceeded 500. Most cases are in the south-central and western states. It is mostly viewed as a disease of the northern hemisphere (between 30- and 71-degrees N latitude) although a few cases have been reported in a subspecies in Australia.

Transmission by insects is more common in Russia, Finland, and Sweden while infected meat is more common in Western and Central Europe. Contaminated water is more common in Turkey.

The disease can be treated with antibiotics.

The disease is very rare in travellers, however, the risk might be greater for those visiting rural or agricultural areas. The disease is mostly identified in people working in outdoor activities or handling the flesh of dead animals. It is possible many cases go undiagnosed. Much can be done to reduce exposure to infected insects, particularly ticks.

• Be aware that ticks in the area may carry the disease. Seek information on whether any outbreaks have been reported.
• Take particular care in the season of risk (May to November).
• Avoid contact with wild animals.
• Wear gloves if handling any carcasses.
• Wear appropriate clothing to reduce the likelihood of any attachment to the skin. This would include long-sleeved shirts and trousers. Socks should be pulled up over the bottoms of the trousers. Consider impregnating your “hiking clothes” with permethrin. Understand how this should be best applied to the clothing and how many washes before retreatment should be done.
• Wear light coloured clothing. Ticks are easily seen and might refrain from attachment.
• Use known effective repellents on the skin.  These include DEET or Picaridin containing products.
• Avoid known tick habitats such as bushy areas with high grass in the high-risk season.
• Stay as much as you can to paths and avoid encountering low bushes.
• Perform tick checks after finishing outside activities and remove any ticks as soon as possible.  Check arm pits and groin areas closely. Other areas include the belly button. behind the ears and knees. Clean any affected area with antiseptic. It is suggested that it takes more than 24 to 36 hours for a tick to transmit the disease once attached.
• Use the proper technique to remove any tick.  Use tweezers as close to the skin as possible and avoid squeezing the body of the tick. Gloves are recommended to avoid any fluid exposure.  See Tick Removal and testing.
• Shower in hot water and check for any ticks.
• Inspect your underclothes closely and wash your hiking clothes with hot water as soon as possible. Putting them in a dryer adds extra protection. It is always advisable to travel with extra hiking gear if washing and drying isn’t always available.

See more mosquito avoidance measures.

The organism, Francisella tularensis, was named after the physician, Dr Edward Francis. He and 5 of his laboratory co-workers were all infected during autopsies on rodents in 1919.

In 1928 he made the link with deer fly fever where the organism was transmitted from rabbits to humans.

It was first discovered in Tulare County, California in 1911 and initially named Bacterium tularense. It was renamed in 1974 in recognition of the work done by Dr Francis.

The bacteria is highly infectious and has been since been studied as a potential bioweapon by several countries.