| |
Encephalitis is most commonly caused by a viral infection, which can be contracted through insect bites, food, drink or skin contact. When the virus is in the bloodstream it localises in the brain. This causes swelling and can lead brain damagecaused by inflammation of the brain.
- Australian Encephalitis
Symptoms of Australian Encephalitis - vary from mild to severe with permanent brain damage or sometimes death. It has been found across the Australian mainland and is passed from water birds to humans via mosquitoes. Only one person in 500 infected becomes noticeably ill, although if they do the common symptoms are fever, anorexia and headache sometimes along with vomiting, nausea, diarrhoea and dizziness. In severe cases, brain function may be impaired after a few days and lethargy, irritability, drowsiness and confusion may set in. Convulsions and fits come next leading to the possibility of coma and death.
- California Encephalitis
Covers a group of viruses carried by mosquitoes and some mammals. It is most likely to affect children and many cases produce no symptoms. In those cases where they become apparent, symptoms are likely to be mild. They start with a slight fever or headache but fast develop into severe headache, high fever, muscle aches, stiffness in the back of the neck and disorientation. There is a risk of permanent brain damage in severe cases. As with other insect-borne disease, outbreaks are most likely to occur during mosquito breeding season.
- Colorado Tick Fever
The Colorado Tick Fever (CTF) virus is transmitted exclusively by female wood ticks and causes fever, chills, headaches along with nausea and vomiting. A small minority of patients suffer a more severe form of the disease, including anorexia and fatigue which takes several weeks to overcome, while children sometimes suffer from a pronounced rash and internal bleeding. The disease is limited to the western US and is most prevalent from March to August.
- Eastern Equine Encephalitis The eastern equine encephalitis virus has a complex life cycle involving birds and a specific type of mosquito, Culiseta melanura, that lives in marshes and swamps. These mosquitoes feed only on birds; they do not feed on humans and other mammals. In rare cases, however, the virus can escape from its marsh habitat in other mosquitoes that feed on both birds and mammals (including horses and humans). These mosquitoes can transmit the virus to animals and people. After infection, the virus invades the central nervous system, including the spinal cord and brain. It is found mainly on the east coast of the US. Some get symptoms similar to a mild case of flu - fever, headache, and sore throat - while others will suffer infection of the central nervous system, which leads to severe headache, seizures and coma. Symptoms appear within four to 10 days of infection. Young children and people over 55 are most at risk.
- Herpes Simplex Encephalitis
Herpes-related encephalitis can erupt rapidly, and may cause seizures or mental changes and even lead to coma or death. It occurs when the herpes simplex type I virus travels to the brain rather than moving through the body to the surface of the skin and producing its more common symptom, a cold sore. Early recognition and treatment of herpes encephalitis can be life saving.
- Hashimoto's Encephalitis
Hashimoto's encephalitis is a rare disease that is associated
with hypothyroidism. It is suspected that thyroid auto antibodies
in serum are raised which attack the healthy cells and organs
such as the brain. Symptoms such as dementia, myoclonus, ataxia,
and epileptic seizures were observed in patients.
- Japanese Encephalitis
Japanese Encephalitis -Mosquitoes transfer the virus that causes the disease from infected animals - usually pigs and wading birds - to humans. It occurs mainly in the rural areas of China and Korea, but is also found in most countries of South and East Asia. Most people who are infected show only mild symptoms or no symptoms at all, although, at advanced stages, the disease may be fatal. It begins like flu with headache, fever, and weakness, and vomiting, confusion and delirium may also be present. In about one of every 200 cases, the illness progresses to inflammation of the brain, with more than half of those cases ending in permanent disability or death.
- LaCrosse encephalitis
LaCrosse encephalitis gets its name from LaCrosse, Wisconsin, where the infection was first recognized in 1963. LaCrosse encephalitis is one of a group of mosquito-borne virus diseases that can affect the central nervous system and cause severe complications and even death. The LaCrosse encephalitis virus has a complex life cycle involving chipmunks and squirrels and a specific type of woodland mosquito (Aedes triseriatus). This mosquito breeds in tree holes and manmade containers and bites during the day. In rare cases, people who live in or visit an area where the virus lives can be infected by the bite of an infected mosquito.
- Murray Valley Encephalitis
Symptoms of Murray Valley Encephalitis - vary from mild to severe with permanent brain damage or sometimes death. It has been found across the Australian mainland and is passed from water birds to humans via mosquitoes. Only one person in 500 infected becomes noticeably ill, although if they do the common symptoms are fever, anorexia and headache sometimes along with vomiting, nausea, diarrhoea and dizziness. In severe cases, brain function may be impaired after a few days and lethargy, irritability, drowsiness and confusion may set in. Convulsions and fits come next leading to the possibility of coma and death.
- Rasmussen Encephalitis
Rasmussen's encephalitis is a rare progressive neurological disorder, characterized by frequent and severe seizures, loss of motor skills and speech, hemiparesis (paralysis on one side of body), encephalitis (inflammation of the brain), dementia, and mental deterioration. The disorder, which affects a single brain hemisphere, generally occurs in children under the age of 10. Although anti-epileptic drugs may be prescribed initially, they are usually not effective in controlling the seizures. Alternative treatments may include plasmapheresis (removal and reinfusion of blood plasma), ketogenic diet, and steroids.
- Russian spring-summer encephalitis
Russian spring-summer encephalitis, transmitted by Ix. persulcatus
ticks, occurs in China, Korea, Japan, and eastern areas of Russia.
A viral infection of the central nervous system transmitted by
bites of certain vector ticks. Human infections follow bites of
infected Ixodes ricinus ticks, usually in people who visit or
work in forests, fields, or pastures. Infection also can be acquired
by consuming un pasteurized dairy products from infected cows,
goats, or sheep.The severity of disease, incidence of sequelae,
and case-fatality rates are higher in the Far East and eastern
regions of Russia than in western and central Europe.
- St Louis Encephalitis
St Louis encephalitis (SLE) is one of the most common viral encephalitis in the US. It is thought to occur naturally in birds and is spread by a mosquito (primarily the Culex species) that become infected with St. Louis encephalitis virus (a flavivirus antigenically related to Japanese encephalitis). In severe infection, it produces flu-like symptoms such as headache, high fever, neck stiffness, disorientation, coma, tremors, occasional convulsions (especially in infants) and spastic paralysis. The elderly are most at risk from the virus. Incubation period for St. Louis encephalitis is usually 5 to 15 days.
- Tick borne Encephalitis
Tick borne encephalitis (TBE), also known as spring-summer encephalitis,
is a viral infection of the central nervous system transmitted
by bites of certain vector ticks. Human infections follow bites
of infected Ixodes ricinus ticks, usually in people who visit
or work in forests, fields, or pastures. Infection also can be
acquired by consuming un pasteurized dairy products from infected
cows, goats, or sheep. The disease occurs in Scandinavia, western
and central Europe, and countries that made up the former Soviet
Union. Risk of acquiring the disease is greatest from April through
August
.
- West Nile Encephalitis
West Nile Encephalitis is a viral disease spread mainly through the bite from an infected mosquito. The West Nile virus is carried long distances by infected birds and then spread locally by mosquitoes that bite these birds. The mosquitoes can pass the virus to humans when they bite. Symptoms include headache, weakness, fever and sometimes nausea and vomiting. In addition, skin rashes are common. It has been commonly found in humans, birds and other animals in Africa, Eastern Europe West Asia and the Middle East, and has only become present in North America since the summer of 1999.
- Western Equine Encephalitis
Western equine encephalitis is a disease that is spread to horses and humans by infected mosquitoes. It is one of a group of mosquito-borne virus
diseases that can affect the central nervous system and cause severe complications and even death. Western Equine Encephalitis is less often fatal
than its eastern namesake and is found in the western and central US. The effects of infection range from no symptoms to fatal disease. Milder effects
consist of a headache with, perhaps, a fever while the severe form causes sudden high fever, headache, drowsiness, irritability, nausea, and vomiting.
This is followed by confusion, weakness, and coma or, in young infants, seizures. Symptoms usually appear within five to 10 days of infection, there
is no cure and people of all ages are at equal risk. |
|
 |
