Summary about Disease
Tick-borne encephalitis (TBE) is a viral infectious disease involving the central nervous system. It is transmitted to humans through the bite of infected ticks, primarily in wooded and bushy areas. The disease can manifest as a range of illnesses, from mild flu-like symptoms to severe neurological complications like encephalitis (inflammation of the brain), meningitis (inflammation of the membranes surrounding the brain and spinal cord), or myelitis (inflammation of the spinal cord). In some cases, it can lead to long-term neurological sequelae or even death.
Symptoms
TBE often presents in two phases.
First phase (initial viremic phase): This phase typically includes flu-like symptoms such as:
Fever
Fatigue
Headache
Muscle aches
Nausea
Second phase (neurological phase): After a symptom-free interval (usually about a week), some individuals progress to the second phase, characterized by neurological symptoms:
High fever
Severe headache
Stiff neck
Vomiting
Confusion, disorientation
Seizures
Paralysis (in some cases)
Cognitive impairment
Causes
TBE is caused by the tick-borne encephalitis virus (TBEV), a member of the Flaviviridae family. The virus is transmitted to humans primarily through the bite of infected ticks. Less commonly, it can be transmitted through consumption of unpasteurized dairy products (e.g., milk or cheese) from infected animals. The primary tick vectors are Ixodes ricinus (in Europe) and *Ixodes persulcatus* (in Asia).
Medicine Used
There is no specific antiviral treatment for TBE. Treatment focuses on supportive care to manage symptoms and prevent complications. This may include:
Pain relievers and fever reducers: To alleviate fever, headache, and muscle aches.
Intravenous fluids: To maintain hydration.
Ventilatory support: In severe cases with respiratory compromise.
Management of seizures: If seizures occur.
Physical therapy and rehabilitation: To address any long-term neurological deficits.
Is Communicable
? TBE is not directly communicable from person to person through normal contact. The virus is primarily transmitted through tick bites or, rarely, through consumption of unpasteurized dairy products from infected animals.
Precautions
Preventing tick bites is crucial to avoid TBE. Key precautions include:
Avoid tick-infested areas: Especially during peak tick activity seasons (spring, summer, and fall).
Wear protective clothing: Long sleeves, long pants tucked into socks or boots, and light-colored clothing (to easily spot ticks).
Use insect repellents: Apply insect repellents containing DEET, picaridin, or other EPA-approved ingredients to skin and clothing, following label instructions.
Check for ticks regularly: Perform thorough tick checks on yourself, your children, and pets after spending time outdoors. Pay close attention to areas like the hairline, behind the ears, and in skin folds.
Remove ticks promptly and correctly: Use fine-tipped tweezers to grasp the tick as close to the skin's surface as possible. Pull upward with steady, even pressure. Do not twist or jerk the tick, as this may cause the mouthparts to break off and remain in the skin. After removing the tick, clean the bite area and your hands with soap and water.
Vaccination: Vaccination is available and highly recommended for individuals living in or traveling to high-risk areas, especially those involved in outdoor activities.
Consume pasteurized dairy products: Avoid consuming raw or unpasteurized milk or cheese, especially from animals in endemic areas.
How long does an outbreak last?
The duration of increased TBE cases is typically seasonal, corresponding to the peak activity of ticks, which is influenced by weather conditions. Outbreaks or increased incidence usually occur during the spring, summer, and fall months, when ticks are most active. The exact duration can vary depending on the geographic location, specific environmental factors, and the effectiveness of public health interventions.
How is it diagnosed?
TBE is diagnosed based on a combination of factors:
Clinical symptoms: The characteristic symptoms of the illness, especially the presence of neurological signs.
Travel history: History of travel to or residence in TBE-endemic areas.
Laboratory tests:
Serological tests: Detection of TBE virus-specific antibodies (IgM and IgG) in the blood or cerebrospinal fluid (CSF). IgM antibodies usually indicate a recent infection, while IgG antibodies may indicate past infection or vaccination.
PCR: Detection of TBE virus RNA in blood or CSF, particularly during the early stages of the infection.
CSF analysis: Examination of the cerebrospinal fluid to look for signs of inflammation, such as increased white blood cell count and protein levels.
Neuroimaging: MRI of the brain may show signs of inflammation or other abnormalities.
Timeline of Symptoms
The typical timeline of TBE symptoms is as follows:
Incubation period: 4-28 days (average of 7-14 days) after the tick bite.
First phase (viremic phase): 3-7 days of flu-like symptoms (fever, fatigue, headache, muscle aches, nausea).
Symptom-free interval: Approximately 1 week.
Second phase (neurological phase): Develops in 20-30% of infected individuals. Neurological symptoms (high fever, severe headache, stiff neck, vomiting, confusion, seizures, paralysis) can last for several weeks to months.
Recovery: Recovery can be slow and may be incomplete, with some individuals experiencing long-term neurological sequelae.
Important Considerations
TBE is a serious illness that can lead to significant neurological complications and even death.
Early diagnosis and supportive care are important to minimize the risk of long-term sequelae.
Vaccination is an effective way to prevent TBE, especially for those at high risk of exposure.
Awareness of the risk of TBE in endemic areas and taking precautions to prevent tick bites are essential for reducing the incidence of the disease.
Long-term neurological complications can include cognitive impairment, paralysis, and epilepsy.
The severity of the disease can vary depending on the specific TBE virus subtype, the age of the patient (older individuals tend to have more severe outcomes), and the presence of underlying health conditions.