Borrelia or Bust – Relapsing Fever Borreliosis Recurrentis

by lmatthews on December 27, 2012

relapsing fever tick soft bodied ornithodoros

The soft-bodied ticks that transmit relapsing fever bacteria can lay dormant for 7yrs without a blood meal.

Lyme disease is not the only condition caused by infection with Borrelia species. There are many different species of this bacteria, including several that are known to cause Lyme disease symptoms and one of which is known to cause louse-borne relapsing fever (LBRF). However, the last known case of LBRF in the US was recorded in 1871, making it a pretty unlikely culprit for feverish symptoms. Tick-borne relapsing fever (TBRF) is caused by at least fifteen Borrelia species, and TBRF, Lyme disease, syphilis and leptospirosis are all the result of bacterial infection with spirochaetal species.

Symptoms of Relapsing Fever Borreliosis Recurrentis

Relapsing Fever Borreliosis Recurrentis is an infection that results in recurrent episodes of fever in-between increasing periods without fever (usually three days of fever followed by a week without fever, recurring). The main symptoms, aside from recurring fever, include: headache, muscle and joint aches, and nausea. Lice spread the bacteria in some places, while ticks are responsible for other cases.

Soft-Bodied vs Hard-Bodied Ticks

The bacteria that cause TBRF include Borrelia hermsii, Borrelia turicatae, Borrelia parkeri, and Borrelia duttonii and they are transmitted through bites from a soft-bodied tick, Ornithodoros, that is able to live for many years, unlike the hard-bodied ticks that transmit Lyme disease bacteria. These kinds of ticks are also able to fast for long periods with some even seen to transmit spirochaetes in the laboratory after seven years without a blood meal. Luckily, the Lyme disease-carrying ticks, Ixodes scapularis, et al, do not survive quite this long and require a blood meal for each stage in their lifecycle.

Zoonosis and a Host Reservoir for Lyme Disease

Humans are the only host for the lice that transmit B.recurrentis, but the ticks that carry Lyme disease bacteria and other strains of Borrelia are able to use a variety of mammals and reptiles as hosts, thus creating a zoonosis and host reservoir for the infection. Fewer than thirty cases of tick-borne relapsing fever are diagnosed in the US each year, with B hermsii and B turicatae behind most outbreaks. Cases are usually in the western US and are often linked to sleeping in rustic cabins with rodent infestations in mountain regions.

TBRF and LBRF in the US

Although LBRF is uncommon in the US it is sometimes the cause of symptoms in travellers returning from overseas where the infection is endemic in some refugee settings. As with Lyme disease, the infection that causes relapsing fever Borreliosis is considered treatable with a short course of antibiotics, although some complications may arise in rare cases. Should there be a suspicion of infection with TBRF or LBRF it is important to be tested and receive appropriate treatment, although early symptoms may be mistaken for an influenza infection or Lyme disease in those familiar with the condition.

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