Introduction of borrelia
Borrelia is a genus of spiral-shaped bacteria belonging to the
spirochete group. These microorganisms are transmitted to humans and animals
primarily through the bites of infected ticks and lice. They are known for
causing important diseases, most notably Lyme disease, which is caused by Borrelia burgdorferi, and
relapsing fever, caused by other Borrelia
species. The bacteria are characterized by their corkscrew-like
motility, which allows them to move easily through tissues and fluids in the
host. Infections with Borrelia can lead to a wide
range of clinical symptoms, from mild fever and fatigue to severe neurological,
cardiac, and joint complications if left untreated. Because of their complex
life cycle involving both arthropod vectors and vertebrate hosts, Borrelia species are considered medically significant
pathogens worldwide.
What is borrelia?
Irregular
spirals, highly flexible and Stain readily with bacteriologic dyes as well as
with blood stains such as Giemsa or Wright stain. Can be grow in fluid media containing blood
serum or tissue. The antigenic structure of the organism changes in the course
of a single infection. The relapsing course of the disease appears to be due to
the multiplication of such antigenic variants.
Antibodies develop in high titter.
Types of borrelia
1. Relapsing fever group
The
relapsing fever group refers to a cluster of Borrelia species that cause
relapsing fever, a disease marked by repeated episodes of high fever separated
by periods without fever. These bacteria are usually transmitted to humans by
lice (Borrelia recurrentis) or by soft
ticks (Borrelia hermsii,
Borrelia duttonii,
and others). The name “relapsing” comes from the pattern of illness, as the
fever returns multiple times due to the bacteria’s ability to change its
surface proteins and evade the immune system. This group is distinct from the
Lyme disease group of Borrelia.
Relapsing
fever – febrile illness characterized by recurrent episodes of fever and
septicemia separated by afebrile periods. Two types:
a) Epidemic/louse
born is
caused by B. recurrentis and is transmitted by human lice (pediculus humanus).
b) Endemic/tick born – is caused by many Borrelia species (15), B.duttoni, B.hermsii and is transmitted by ticks (Orinthodoros).
2. Lyme disease
Named after
the town of Lyme - a number of cases were first discovered in 1975. Tick born disease (transmitted from mice by
ticks) Involves dermatologic, rhematologic, neurologic and cardiac
abnormalities. Transmitted by 10 Borrelia species and three species are
associated with human disease (B. burgdorferi, B.garinii, B. afzelii).
Transmitted to humans by the saliva of the tick which contaminates the site of
the bite.
Sign and symptoms of lyme
Early stage
· Unique skin
lesions (rash) occurs 3-4 weeks after a tick bite
· The lesion is a
flat reddened area near the tick bite and slowly expands with central clearing
· There is also
flue like illness with fever, chills, myalgia and headache
Late stage
- Occurs weeks to months later
- Includes arthralgia and arthritis
- Meningitis
- Facial nerve palsy
- Painful radiculopathy
- Cardiac disease
- It might be associated with deposition of Ag-Ab complexes.
Epidemiology of lyme disease
Mice and
deer are main animal reservoirs of B.burgdorfeeri. Most exposures are in May through July, when
the lymphal stage of the ticks is most active. Prevention avoidance of exposure
of ticks Long sleeves and long pants tucked in to socks are recommended.
Diagnosis
Microscopy examination of blood is not recommended (B.bugdorfeeri rarely seen in clinical specimen) Culture: Needs special media Serology: Is an important diagnostic method Immunofluorescence assay (IFA) and Enzyme linked immunosorbent assay (ELISA).
Haw to treatment Lyme disease
At the early
stage, doxycycline, amoxicillin, or erythromycin. In later stages, intravenous
penicillin or ceftriaxone.
Haw to prevention borrelia
Prevention
of Borrelia infection depends mainly on avoiding contact with the ticks or lice
that transmit the bacteria. People should limit exposure to areas where ticks
are common, such as dense forests and tall grasses, and use protective clothing
like long sleeves and trousers. Insect repellents with DEET on the skin or
permethrin on clothing are helpful in reducing the risk of bites. After outdoor
activities, it is important to check the body carefully and remove any ticks
immediately with fine tweezers to stop transmission. Keeping the home
environment clean by trimming grass, removing leaf litter, and controlling
rodents can also reduce the presence of ticks. In the case of louse-borne
Borrelia, personal hygiene, regular washing of clothes, and avoiding overcrowded
living conditions are essential measures for prevention. Avoid tick bite, use
insecticides, insect repellent.
Conclusion
In conclusion, Borrelia is a group of bacteria that cause important human
diseases such as Lyme disease and relapsing fever, mainly transmitted through
ticks and lice. These infections can lead to serious health problems if left
untreated, but with proper awareness, early diagnosis, and timely antibiotic
therapy, most cases can be managed effectively. Preventive measures, including
personal protection from vectors and maintaining good hygiene and environmental
control, play a crucial role in reducing the risk of infection.
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