The bacterial infection mostly found in parts of the United States, Tick-Borne Relapsing Fever can be spread through multiple tick species. Ornithodoros hermsi is commonly known to spread bacterial infections in the human race.
The tick can be found in coniferous forests which are at altitudes of 1500 to 8000 feet where it mostly feeds on tree squirrels and chipmunks.
Other than Ornithodoros hermsi, O. parkeri and O. turicata are the other two species that are commonly known for their spread. They were located in the ground holes dug by squirrels, prairie dogs, and burrowing owls.
These grounds are usually more active during summer when people indulge in vaccination or activities which are located near rodent-infested cabins.
TBRF can also occur in the western United States, where people usually sleep in rustic and rodent-infested cabins in areas like mountains. The bacterial infection not only lead to Tick-Borne Relapsing Fever but also lead to other types of fevers like:
Spiral-shaped bacteria, which can be transmitted from human to human by the body louse. It is caused due to Borrelia recurrentis. LBRF outbreaks are common in overcrowding and social disruption.
Closely related to TBRF, Borrelia miyamotoi is a spiral-shaped bacteria. It is also quite identical to the bacteria which causes Lyme disease.
The borrelia miyamotoi disease is detected in only two types of ticks, The blacklegged or “deer” tick (Ixodes scapularis) and the blacklegged or “deer” tick (Ixodes scapularis).
Borrelia bacteria that cause various types of fevers are transmitted through soft ticks from the genetic footprint of Ornithodoros. Soft ticks are quite different as compared to hard ticks.
Unlike hard ticks, soft ticks wait in the rodent’s burrows and prey when their target rodent is asleep. Also in terms of duration, the soft tick can sustain on a rodent’s body only for 30 minutes.
Soft tick bites are painless and feel less for a human body. The ticks mostly emerge at night when the person is sleeping and return to their host burrows. The transmission can occur only in rodent-infested areas like sleep cabins with poor hygiene practice.
Several species of Borrelia ticks can cause Tick-Borne Relapsing Fever. Some of the species are:
Soft life has a lifeline of up to 10 years, in certain species found in parts of Russia it has been found to live almost 20 years. The lifeline of the soft tick depends on the location of the infestation, for instance, ticks infested in lifeless rodent homes may live less than one’s living in the rodent nest near to livelihood.
Similar to the hard ticks, soft ticks also need blood to survive through each stage of their lives. Although, soft ticks can pass the inherent bacterial infection to their offsprings. Since the lifespan of soft ticks is quite long, they may remain infested until hard steps are taken to remove the nest.
Most of the people come in contact with soft ticks in the infected rodent area. Two epidemiological types of TBRF are:
The capacity for rodent reservoirs in dig burrows depends on the overall hygiene of the area. It usually occurs in developing countries where hygiene is quite poor.
In both of the cases, the probability of infection in humans depends upon other factors like age or gender, duration of exposure, the intensity of bacteria, lifestyle habits, immunity level of an individual, or congenital transmission.
Relapsing fever is a bacterial infection that is known for its recurrent symptoms. Tick-borne relapsing fever is a rare condition that is mostly found in the areas of western United States. Most of the symptoms include:
These symptoms are primary symptoms, and may lead to the secondary type of symptoms like:
Is an illness comprising yellowing of the eyes and mucous membranes due to an increased level of bilirubin, a yellow-orange bile pigment.
Enlargement or inflammation in the liver.
Enlargement of the spleen.
Enlargement or inflammation of conjunctival vessels.
Development of dead tissue on the skin after an injury.
Inflammation of the three membranes that cover the brain and spinal cord.
Stiffness in the neck muscles.
Pain in a different body muscle.
Pain in different joints of the body.
Since the nature of the bacteria makes these symptoms recur, The pattern of the fever may represent three days of fever followed by seven days of neutral health followed by another three days of fever. Without any proper treatment, the symptoms may last longer.
Along with fever, the patient might experience nonspecific symptoms. The three days of fever and infection are known as febrile episodes and the seven-day relief period is known as afebrile periods. Each episode of febrile consists of a sequel of symptoms known as “crisis” or “chill phase” mode.
It consists of a high fever of up to 106.7°F or 41.5°C which may be agitated, delirious, tachycardic and tachypneic, and last up to 30 minutes. The chill phase is often followed by the “flush phase”, which consists of a rapid decrease in body temperature and drenching sweats. If not treated well, the flush phrase can also develop transiently hypotensive.
Physical examination may consist of records of medical history and diagnosis of the symptoms. The tolerance shows signs of mild fever and is dehydrated. Also, a macular rash or scattered petechiae may present at the sight of the bite.
Due to the presence of primary symptoms, secondary symptoms like jaundice, hepatosplenomegaly, meningismus, and photophobia. In some rare cases, some patients might develop neurologic involvement.
Tick-Borne Relapsing Fever often creates high concentrations of spirochetes in the bloodstream. It can be easily diagnosed with direct microscopic examination with the help of dark field microscopy and stained peripheral blood smears. In both febrile episodes and afebrile periods, the presence of spirochetes is common.
Other bacteria, such as Helicobacter, can also be diagnosed with the same method of examination. So it is important to contemplate geographical and clinical characteristics while conducting diagnosis for Tick-Borne Relapsing Fever.
Serologic testing for the diagnosis of TBRF may not reflect accurate results and the results may vary in each test. Serum taken during the early stages of infection may give negative results.
For more accurate results, medical professionals may conduct multiple tests. Each test shall be conducted in at least 21 days. The result may vary from negative to positive due to the development of an IgG response in the convalescent sample.
Early antibiotic treatment of the case may limit the antibody response present in the bloodstream.
Due to the presence of similar proteins between the causative organisms, In both Lyme disease and TBRF, the examination may show a false-positive test result. Medical professionals recommend constant testing in case of positive Lyme disease serology.
Laboratory findings may include:
There is no specific treatment developed for TBRF, although the group of spirochetes or spiral-shaped bacteria can be treated with the following medication:
Single-dose each day, 200,000 units for children ages 12 years or less, and 500 mg or 600,000 IU for adults.
Like Macrolides and Fluoroquinolones are quite effective to cure a bacterial infection.
Dose of 500 mg every 6 hours for 10 days preferred for an oral regimen in adults. It is an effective alternative in the case of tetracyclines contraindicated.
Dose of 2 grams per day for a time period of 10-14 days is preferred for patients with central nervous system involvement, similar to early neurologic Lyme disease.
It is advisable to closely monitor the patient during the first four hours of antibiotic therapy and treatment as one might develop a case called Jarisch-Herxheimer reaction.
Jarisch Herxheimer reaction (JHR) is a condition that may develop during antibiotic treatment in the case of spirochetes infection.
If not treated by JHR, the reaction may worsen as time. It has been seen that 50% of the cases develop symptoms like, hypotension, and high fever which may worsen JHR.
Optimum usage of Cooling blankets and antipyretic agents is recommended. Since some of the symptoms include infection in the respiratory tract, the treatment of mild or severe cases needs incubation and isolation during the treatment of Tick-Borne Relapsing Fever.
Most of the cases of Tick-Borne Relapsing Fever, get recovered from a combination of antibiotics and pain relief medication. Although, in some of the cases TBRF may lead to iritis, uveitis, cranial nerve, and other neuropathies.
Also, Cardiac and neurologic complications can be developed in the long term or critical cases of Tick-Borne Relapsing Fever.
Case can become quite complicated if the patient is going through her pregnancy. Tick-Borne Relapsing Fever can lead to abortion, premature birth, and neonatal death.
It has been seen that the bacterial infection of pregnant mothers can be transferred through the fetus via the birth canal. Research has shown that infants are infected during the fetal stage showing signs of underweight, and higher perinatal mortality.
Scientists still have not discovered the relation of the immunity system with TBRF. Although, there have been some cases in which the tolerant get infected with the disease more than once.
Soft ticks can be prevented in the living environment by maintaining proper management and hygiene. One can also opt for various rodent prevention methods to remove and prevent any rodent infestation.
While visiting a tick-oriented area make sure to use tick repellent, and wear fully covered clothing that will protect you from tick bites. Especially for children and people with low immunity.
Women who are pregnant or expecting to get pregnant should avoid areas that might be infested with rodents or ticks as Tick-Borne Relapsing Fever can be passed to offsprings.