Encephalitis: EEE, Causes, Symptoms, Contagious & Treatment

Encephalitis

Contents

Encephalitis facts

  • Encephalitis is inflammation of the brain.
  • Bacteria or viruses, and rarely a fungus, or be noninfectious in origin can cause encephalitis.
  • Symptoms of encephalitis include fever and headache, in addition to lethargy and confusion.
  • Health care professionals make a diagnosis of encephalitis by performing a spinal tap to examine the cerebral spinal fluid. A CT scan or MRI of the brain may also be of use.
  • The underlying cause of the encephalitis determines the treatment. If bacteria cause the encephalitis, then a doctor will prescribe antibiotics.
  • Anyone experiencing encephalitis symptoms should seek medical treatment immediately.
  • Close contacts can contract encephalitis also and will need medical evaluation.

Encephalitis Symptom

Photophobia

Sensitivity to light is the inability to tolerate light, medically known as photophobia. In someone who is light sensitive, any type of light source (sunlight, fluorescent light, incandescent light) can cause discomfort. Photophobia typically causes a need to squint or close the eyes, and headache, nausea, or other symptoms may be associated with photophobia. Symptoms may be worse with bright light. People with light-colored eyes are more likely to have sensitivity to bright light than those with darker-pigmented eyes. Light sensitivity is caused by a number of conditions that affect the eye (such as iritis, uveitis, and keratitis), as well as conditions that affect the entire body.

What is encephalitis?

Encephalitis is brain inflammation.

What causes encephalitis?

  • Encephalitis is a rare condition that is most often caused by viruses (viral encephalitis).
  • It can also be caused by noninfectious diseases, such as systemic lupus erythematosus and Behçet’s disease (an autoimmune disorder).
  • The leading cause of severe encephalitis is the herpes simplex virus.
  • Other causes include enterovirus infections or mosquito-borne viruses.
    • Eastern equine encephalitis (EEE),
    • Western equine encephalitis (WEE),
    • Venezuelan equine encephalitis (VEE),
    • Japanese encephalitis, and
    • Zika virus.
  • The very young and the elderly are more likely to have more severe encephalitis.

Exposure to viruses can occur through breathing in respiratory droplets from infected people, certain insect bites, and direct skin contact.

What are the risk factors for encephalitis?

Patients with suppressed immune systems (due to medications or diseases) have an increased risk for encephalitis.

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Is encephalitis contagious?

Infectious forms of encephalitis are contagious. Viral and many bacterial forms of encephalitis are contagious. Several forms of bacterial encephalitis can be spread by respiratory and throat excretions. Encephalitis can also be caused by an infection in the body that spreads to the brain. Noninfectious encephalitis, such as from diseases systemic lupus erythematosus and Behçet’s disease, are not contagious.

What are encephalitis symptoms and signs?

The signs and symptoms of encephalitis can range from very mild flu-like symptoms to potentially life-threatening events. Signs and symptoms of encephalitis include

Anyone experiencing symptoms of encephalitis should see a doctor immediately.

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What specialties of doctors treat encephalitis?

People with encephalitis usually need treatment in the hospital. A family practice or general internal-medicine physician or an infectious-disease specialist will usually treat someone with encephalitis.

How do health care professionals diagnose encephalitis?

A health care professional diagnoses encephalitis after performing a thorough history and exam. The exam will incorporate special techniques to look for signs of inflammation of the membranes that surround the spinal cord and brain (meninges). The doctor will order specific tests to help determine the diagnosis.

Tests that evaluate individuals suspected of having encephalitis include cerebrospinal fluid analysis, brain scanning (such as CT scan or MRI scan), and an evaluation of the blood for infection and the presence of bacteria.

The most common method of obtaining a sample of cerebrospinal fluid (or CSF) for examination is a spinal tap. A spinal tap, or lumbar puncture (LP), involves the insertion of a needle into the fluid within the spinal canal. The needle goes between the spine’s bony parts until it reaches the CSF. A medical professional then collects a small amount of fluid to send to the laboratory for exam. Evaluating the CSF is necessary for a definitive diagnosis of encephalitis and to decide on the best treatment options.

Abnormal spinal fluid results confirm the diagnosis and, in the event of an infection, by identifying the organism that caused the infection.

QUESTION

What is the treatment of encephalitis?

People require urgent treatment with antibiotic and/or antiviral medications if a physician suspects that person has encephalitis. Patients may need to take sedatives for irritability or restlessness. Doctors may administer other medications to decrease the fever or treat headaches.

Is it possible to prevent encephalitis? Is there an encephalitis vaccine?

Basic steps to avoid spread of infections (hand washing, covering mouth when coughing, etc.) can help prevent encephalitis.

Some vaccinations for bacterial or viral diseases can help prevent encephalitis.

What is the prognosis (outlook), and what are the complications for patients with encephalitis?

The prognosis for encephalitis varies. Some cases are benign and patients recover fully. Other cases are severe. The type of infection present and how quickly treatment starts determine the prognosis. The acute phase of encephalitis may last for one to two weeks, with gradual or sudden resolution of fever and neurological symptoms. Neurological symptoms may require many months before full recovery occurs. Some patients will not fully recover.

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United States. Centers for Disease Control and Prevention. «2012 Recommended Immunizations for Children From 7 Through 18 Years Old.» Jan. 10, 2017. .

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United States. Centers for Disease Control and Prevention. «Vaccines & Immunizations.» Apr. 23, 2018. .

United States. National Institute of Neurological Disorders and Stroke, National Institutes of Health. «Meningitis and Encephalitis Fact Sheet.» July 6, 2018. .

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Headache

Headaches can be divided into two categories: primary headaches and secondary headaches. Migraine headaches, tension headaches, and cluster headaches are considered primary headaches. Secondary headaches are caused by disease. Headache symptoms vary with the headache type. Over-the-counter pain relievers provide short-term relief for most headaches.

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Nausea and Vomiting (Causes, Natural Remedies, Diet, Medication)

Nausea is an uneasiness of the stomach that often precedes vomiting. Nausea and vomiting are not diseases, but they are symptoms of many conditions. There are numerous cases of nausea and vomiting. Some causes may not require medical treatment, for example, motion sickness, and other causes may require medical treatment by a doctor, for example, heart attack, lung infections, bronchitis, and pneumonia.

Some causes of nausea and vomiting may be life threatening, for example, heart attack, abdominal obstruction, and cancers.

Treatment of nausea and vomiting depends upon the cause.

www.medicinenet.com

Encephalitis in Dogs — Symptoms And Treatment

Encephalitis in dogs refers to an inflammation or infection of the brain. The different types of encephalitis in dogs include infectious and/or idiopathic encephalitis. The different types of encephalitis vary depend on the root of the cause. If you notice any of the below mentioned symptoms, we recommend consulting a veterinarian as soon as possible. Treatment of this dog brain disease will depend largely on its diagnosis.

For more about encephalitis in dogs, its symptoms, causes and treatment, keep reading here at AnimalWised.

Encephalitis in dogs: symptoms

What is encephalitis in dogs? Encephalitis defines an inflammation of the brain or encephalon. The most common symptoms of encephalitis in dogs include:

  • Fever
  • Apathy
  • Changes in behavior and personality (increased aggressiveness)
  • Uncoordinated wandering
  • Seizures
  • Stupor
  • Coma

If you notice any of these above symptoms, you should contact your vet immediately. Keep reading to discover causes of encephalitis in dogs.

Encephalitis in dogs: causes

The most common cause of encephalitis is canine distemper, a life-threatening viral disease that is fortunately decreasing in presence thanks to vaccinations. Rabies in dogs, which has also been eradicated in many countries thanks to vaccines, is another viral cause of encephalitis. Canine herpesvirus is also capable of causing encephalitis in newborn puppies less than two weeks of age.

Other more infrequent causes of canine encephalitis are fungal infections caused by fungi, protozoa, rickettsiae or ehrlichiosis. In addition to the brain, a dog’s spinal cord can also suffer damage. Lead encephalitis, can be triggered in dogs that ingest lead materials, such as some paint or plaster. These occur more often than not in puppies. In these cases you may also notice symptoms such as vomiting, diarrhea or constipation.

For more about these above mentioned encephalitis causes, we recommend reading our following articles:

Brain inflammation in dogs: bacterial encephalitis

This type of encephalitis in dogs is caused by bacteria that reaches the brain through the circulatory system. This encephalitis type spreads from the nasal passage or an infected abscess present in areas such as the head or neck.

Brain inflammation in dogs: post-vaccinal encephalitis

Post-vaccinal inclusion body encephalitis in dogs occurs after the use of modified vaccines or modified viruses. This encephalitis type is more likely triggered when both the distemper vaccine and the parvovirus vaccine are given to puppies less than 6-8 weeks old.

Meningitis and encephalitis in dogs

Meningitis is defined as inflammation of the membranes that cover the brain and spinal cord. Its origin is usually rooted in an infected bite, located in the area of the head or neck. In addition, bacterial infections that reach the brain from places like the nose or the ear can also lead to meningitis. The meningitis type, known as aseptic or viral meningitis, often has an unknown origin and affects larger breed puppies under the age of two.

For more, we recommend reading our article where we discuss everything you need to know about meningitis in dogs.

Necrotizing encephalitis in dogs

Necrotizing encephalitis in dogs (NE) is typical of small-sized dog breeds such as pugs or Yorkshire terriers. It is hereditary and affects younger dogs under the age of four. This encephalitis type can attack the whole brain or only specific areas. Even though rare, it circumscribes the optic nerves and can cause sudden blindness. Unfortunately, this disease is progressive and has no treatment. Drugs can, however, be prescribed to slow down its progression.

Encephalitis in dogs: treatment

A diagnosis of encephalitis and meningitis in dogs requires an analysis of a cerebrospinal fluid (CSF) sample, which is extracted by a spinal tap. In addition, a veterinarian will have to perform various test to discover its underlying caused. Treatment and elimination will be based on the specific cause, with the aim of controlling its symptoms.

Corticosteroids may be prescribed to reduce brain inflammation. If the dog is suffering from seizures or convulsions, it may require anticonvulsants. Antibiotics can also be administered to treat encephalitis in dogs, if the cause is rooted in a bacterial infection.

Encephalitis in dogs: sequelae

The added problem of encephalitis in dogs is that, even once recovered, they can have sequelae such as seizures and other neurological symptoms.

Encephalitis in dogs: contagious

The only contagious form of encephalitis and meningitis in dogs is that caused by the canine distemper virus. However, more often that not, canine encephalitis is NOT contagious.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to Encephalitis in Dogs — Symptoms And Treatment, we recommend you visit our Neurological diseases category.

www.animalwised.com

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Tick-borne Encephalitis

Introduction

Tick-borne encephalitis is spread through tick bites and can cause a flu-like illness, fever and headache or lead to meningitis and/or brain inflammation.

Recommendations for Travellers

All travellers planning to spend long periods of time in forested/rural areas of countries with TBE should be aware of how to avoid tick bites.

The most effective way to prevent TBE is through vaccination; this should be considered if you will be spending long periods of time in forested/rural areas of countries with TBE e.g. you are travelling to go hiking, camping, orienteering, walking, running, cycling etc.

Vaccination

The vaccine available in the UK is called TicoVac and TicoVac Junior for children. A vaccination course consists of 3 doses of vaccine, at least 2 doses of which are required before travel.

  • Patient Information Leaflet (PIL) for TicoVac
  • Patient Information Leaflet (PIL) for TicoVac junior
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Overview of Disease

TBE is a viral infection that can affect the central nervous system/brain and is transmitted to humans by a bite from an infected tick. Less commonly the disease can be spread through drinking unpasteurised milk from infected animals, especially goats.

TBE is found in parts of Europe (east, central and north), Russia, China, Japan and South Korea. TBE occurs from late spring until early autumn and is found mainly in rural/forested areas where ticks are common.

Most human infections are contracted during outdoor leisure pursuits such as forestry working, camping, rambling and mountain biking, during tick season (spring to early autumn).

The Illness

Most infections cause no symptoms. When symptoms do develop fever and a flu-like illness is followed by 2 -10 days of no symptoms, before inflammation of the central nervous system occurs with fever, headache and signs of meningitis and/or brain inflammation. Severe disease can cause permanent neurological damage including behavioural/mood changes and reduced concentration. About 1 in 100 patients will die from TBE.

Treatment

No specific treatment is available for TBE.

www.fitfortravel.nhs.uk

Encephalitis in humans: symptoms, treatment, prevention of tick-borne encephalitis

TBE is a viral infection that affects the central nervous system and may cause a spectrum of disease, from a mild short-lived illness to a more severe life-threatening illness

Tick-borne encephalitis

Content Sections

Key Messages

Tick-borne encephalitis (TBE) is a viral infection usually transmitted through the bite of an infected tick.
Areas with known TBE exist within a band that extends from central, eastern and northern Europe across Russia to parts of eastern Asia.
Typically the disease occurs in two stages: The first is a mild-flu like illness. The second is a potentially serious infection of the central nervous system (brain and spinal cord).
TBE is rarely fatal in Europe, however in Asia TBE may be fatal in up to 20 percent of cases. Long-term neurological complications are common.
TBE is a rare disease in UK travellers, however individuals are at increased risk if they visit areas where TBE is known to occur particularly in woodland or grassland e.g. when camping or hiking.
Travellers may reduce the risk of infection by avoiding risk areas and taking bite prevention measures. A vaccine is also available for travellers whose planned activities put them at increased risk.

Overview

Tick-borne encephalitis (TBE) is a viral infection that is transmitted predominantly through the bite of an infected Ixodes tick. The TBE virus belongs to a closely related group of viruses called flaviviruses. These include yellow fever, dengue and Japanese encephalitis. There are three different subtypes of TBE virus: European TBE virus, Siberian TBE virus and Far Eastern TBE virus.

TBE affects the central nervous system and may cause a spectrum of disease, from a mild short-lived illness to a more severe life-threatening illness with the potential for severe neurological complications. The disease occurs in parts of central, northern and Eastern Europe, Siberia and parts of Asia [1]. TBE is rarely fatal in Europe however in Asia may be fatal in up to 20 percent of cases. Long-term neurological problems are common [2].

Risk areas

Areas where TBE occurs exist within a band that extends from central, eastern and northern Europe across Russia to parts of eastern Asia, predominantly within the non-tropical regions of the Eurasian forest steppe. These areas are generally at altitudes lower than 1500m, however they have been noted at higher altitudes [3, 4]. Climate change is thought to have resulted in TBE risk areas moving northward and to higher altitudes. Social, political, ecological and demographic factors are also considered to be important [5]. Within this band TBE occurs in highly focal areas and from year to year the incidence (number of cases) may vary significantly according to local environmental conditions [6]. In Europe and Asia, approximately 10,000-12,000 TBE cases are reported annually [4]. Of these, approximately 2000 cases are reported in Europe each year [6-9].

The general geographical distribution of the three virus subtypes is as follows:

  • European TBE virus – prevalent in Europe and western Russia. Transmitted by Ixodes ricinus
  • Siberian TBE virus – prevalent in parts of Eastern Europe, all parts of Russia and parts of northern Asia. Transmitted by Ixodes persulcatus
  • Far Eastern TBE virus – prevalent in eastern Russia, China and Japan. Also transmitted by Ixodes persulcatus

Vaccination recommendations for countries highlighted in Figure 1 will depend on regions visited within a country, a traveller’s planned activities, the season of travel, and the medical history of the individual traveller. The Country Information pages should be consulted for specific guidance.

Fig 1: NaTHNaC Tick-borne encephalitis country risk map April 2017. This map should be interpreted with caution, as epidemiological information available from different countries may be limited and the risk may be different within a country

Further information on TBE Risk Class as detailed in this map is available in the rationale for country specific disease recommendations.

Risk for travellers

The risk of acquiring TBE infection is dependent on a number of factors including:

  • Destination of travel
  • Duration of travel in risk area
  • Season of travel
  • Activities undertaken
  • Tick activity in the country visited
  • Vaccination status of the traveller
  • Travellers to areas where TBE occurs may be at risk when walking, camping or working in woodland terrain where they will be exposed to the tick vector. Infection may also be acquired by consuming unpasteurised dairy products from infected animals [6]. In Europe the early spring through to late autumn are generally higher risk, but seasons vary according to location [8, 9].

As of December 2016, six confirmed cases of TBE have been reported in the UK since 2011. All the cases had history of travel to the TBE endemic areas of Czech Republic (one case), Latvia (one case), Sweden (three cases) and one case travelled to multiple destinations of (Latvia, Lithuania and Estonia) [10].

Transmission

TBE is usually transmitted through the bite of an infected Ixodes tick, the main vectors of TBE virus. The virus is maintained in nature by a number of animal ‘hosts’ including; small mammals (such as mice and voles), domestic livestock (including sheep, goats and cattle) and certain species of birds. This interaction between vector and host creates a reservoir of disease in the surrounding environment. Human infection occurs incidentally when individuals encroach on the area where the virus is present and are inadvertently bitten by infected ticks [5, 6].

Ticks are found on forest fringes within adjacent grassland, forest glades, riverside meadows and marshland, forest plantations with brushwood, and shrubbery. Ticks can also be found in parks and gardens. They tend to reside on ground level vegetation, on the underside of foliage, from where they can be brushed onto clothing. Ticks are capable of transmitting the TBE virus throughout their lifecycle stages (larvae, nymphs or adults), and once infected, carry the virus for life. Tick activity and development are affected by local climatic factors such as temperature, soil moisture and relative humidity.

The number of ticks infected within risk areas may vary markedly. The number of infected Ixodes ricinus ticks is often low. In some endemic countries in Central Europe the prevalence of the virus in ticks varies from 0.1 to 5% [11]. Unusually, humans may become infected after consumption of unpasteurised dairy produce [9].

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Signs and symptoms

Most people who are infected with TBE virus do not develop symptoms with approximately 2- 30% developing a temperature after an incubation period of around eight days, with a range of two to 28 days [12, 13]. Typically TBE follows two stages with the first stage of the disease lasting from up to a week characterised by a non-specific flu-like illness with fever, fatigue, headache and muscle pains [12, 13]. An interval of 1 to 20 days follows, during which time patients usually have no symptoms [2]. Approximately one third of those with the initial symptoms progress to the second stage of disease [14].

The second stage of TBE is heralded by a sudden rise in temperature with clinical features of: meningitis (inflammation affecting brain lining only), meningoencephalitis (affecting the brain and its lining), and meningoencephalomyelitis (the most severe form also affecting the spinal cord) in about 10 percent of symptomatic cases [12,13]. Cases that progress to the second stage develop long-term neurological complications. According to a 10-year follow-up survey, 80% of patients with the primary meningoencephalomyelitic form developed long term sequelae [14].

The second phase of illness in children is usually limited to meningitis whereas adults older than 40 years are at increased risk of developing meningoencephalitis or meningoencephalomyelitis, with higher mortality in those over the age of 60. The Far Eastern subtype appears to be more severe. TBE is rarely fatal in Europe (0.5 to 2%) however more deaths occur with the Siberian and Far East types [4].

Diagnosis and treatment

Diagnosis of TBE is made when antibodies to the TBE virus are detected in the blood or cerebrospinal fluid. During the first phase of the illness, TBE virus or viral RNA can sometimes be detected in blood samples by virus isolation or PCR. Treatment relies on supportive management; there is no specific anti-viral treatment for TBE. More severely affected individuals may need admission to intensive care with some requiring assisted ventilation [14]. Long-term support for neurological complications may be needed.

Preventing tick-borne encephalitis

Travellers should be advised to:

  • Avoid known heavily tick-infested areas of forest and woodland during the spring, summer and autumn where possible.
  • Practise bite avoidance methods: for example wear appropriate clothing and use effective insect repellents [13].
  • Check the body for ticks regularly. The larval forms of Ixodes ticks are tiny and difficult to see (they can be the size of a freckle or speck of dirt). Adult ticks, once they have fed and become engorged, may be the size of a coffee bean. Common areas for ticks to attach are at the hair-line, behind the ears, elbows, backs of knees, groin and armpits.
  • Remove ticks as soon as possible by using a pair of fine tipped tweezers or tick remover. After a tick has attached itself to the host it may not start feeding for approximately 12 hours [14, 15].
  • Travellers should also avoid consumption of unpasteurised dairy products in areas of risk.
  • If any signs of illness occur within 28 days of a tick bite, advice should be promptly sought from a medical practitioner.
  • TBE vaccination is available for those travellers intending to visit risk areas, or those whose occupation may put them at higher risk (see below).

TBE immunoglobulin (antibodies) was previously used as post-exposure prophylaxis after a tick bite in TBE endemic countries. However, there were concerns that it had a negative effect on the course of disease. TBE immunoglobulin is no longer recommended in the UK or other European countries for treatment.

Vaccine information

Indications for use of TBE vaccine

Tick-borne encephalitis vaccine should be considered for:

  • All persons living in TBE-endemic areas
  • Those at occupational risk in endemic areas, e.g. farmers, forestry workers, soldiers
  • Travellers at risk of disease. See ‘Risk for travellers’ section above
  • Laboratory workers who may be exposed to TBE

Vaccines

TicoVac and TicoVac Junior vaccines (known in some countries as FSME IMMUN and FSME IMMUN Junior) are licensed in the UK.

Details of these vaccines can be found in the summary table below.

Vaccine schedules

The Summary of Product Characteristics (SPC) for the individual vaccines should be consulted prior to the administration of any vaccine [18, 19].

Vaccine Schedule Accelerated schedule Length of protection Age range
TicoVac 0.5ml 3 doses on days 0, between 1 and 3 months, and 5 to 12 months after the second dose* 2nd dose can be given 2 weeks after the 1st dose **First booster no more than 3 years after 3rd dose. After this, boosters may be given at 5 year intervals if at risk Persons at least 16 years of age and older
TicoVac 0.25ml Junior 3 doses on days 0, between 1 and 3 months and 5 to 12 months after the second dose* 2nd dose can be given 2 weeks after the 1st dose First booster no more than 3 years after 3rd dose. After this, boosters may be given at 5 year intervals if at risk Children above 1 year of age and below 16 years of age
* After the first two doses, sufficient protection can be expected for the on-going tick season (protection rate over 90 percent after the second dose)

**In those aged > 60 years, booster intervals should not exceed three years (see below).

The optimum time to begin the course of vaccination against TBE is during the winter months in order to ensure protection prior to the start of the tick season in spring. TicoVac is probably effective against the Far Eastern subtype as well as the European subtype of TBE [18,19]. Booster doses continue to be recommended every three years in adults > 60 years [20].

Contraindications

  • Current febrile illness
  • Allergies to constituents of the vaccine, including severe reactions to egg

Precautions

  • Persons with known or suspected auto-immune disease
  • Persons with pre-existing cerebral disorders
  • Pregnancy
  • Lactation

Adverse events

Adverse reactions following TBE vaccine are most commonly mild and transient. In adults they include local reactions such as swelling, redness and pain at the injection site. Generalised reactions such as fatigue, malaise, headache, muscle pain and nausea have been reported but were transient and usually mild.

Studies in children reported mild local and systemic reactions. The most common local reactions reported were pain and tenderness at the injection site. The most frequently reported systemic reactions were fever and restlessness in young children, as well as headache in all children. Fever, particularly after the first dose, has been reported.

In rare cases, more serious reactions of meningitis and neuritis have occurred.

Resources

First Published : 06 Jul 2015
Last Updated : &nbsp 27 Apr 2017

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