Viral encephalitis

1.  SOMBIR SINGH
 Ph.D
 Center for Biotechnology
MD University Rohtak
sombirkumar9195@gmail.com

2. Encephalitis is the inflammation of the brain
parenchyma, presents as diffuse and/ or focal
neuropsychological dysfunction.
• From an epidemiologic and pathophysiologic
perspective, encephalitis is distinct from
menningitis though on clinical evaluation the two
often coexist with the sign and symptoms of
meningeal inflammation such as photophobia,
headache or a stiff neck.
• Viral infection is the most common and important
cause, with over 100 viruses implicated worldwide

4.  Encephalitis is most often caused by a viral
infection.
 Many types of viruses may cause it.
 Exposure to viruses can occur through:
 Breathing in respiratory droplets from an
infected person
 Contaminated food or drink
 Mosquito, tick, and other insect bites
 Skin contact

5.  Some patients may have symptoms of a cold or stomach infection
before encephalitis symptoms begin.
 When a case of encephalitis is not very severe, the symptoms may
be similar to those of other illnesses, including:
1. Fever that is not very high
2. Mild headache
3. Low energy and a poor appetite
4. Clumsiness, unsteady gait
5. Confusion, disorientation
6. Drowsiness
7. Irritability or poor temper control
8. Light sensitivity
9. Stiff neck and back (occasionally)
10. Vomiting

7. • Herpes viruses – HSV-1, HSV-2, varicella zoster
virus, cytomegalovirus, Epstein-Barr virus, human
herpes virus 6
• Adenoviruses
• Influenza A
• Enteroviruses, poliovirus
• Measles, mumps, and rubella viruses
•Rabies

8. • Arboviruses – examples: Japanese encephalitis; St.
Louis encephalitis virus; West Nile encephalitis
virus; Eastern, Western and Venzuelan equine
encephalitis virus; tick borne encephalitis virus
• Bunyaviruses – examples: La Crosse strain of
California virus
• Reoviruses – example: Colorado tick fever virus
• Arenaviruses – example: lymphocytic
choriomeningitis virus

9. • Arboviruses = arthropod-borne viruses
• Arboviruses are maintained in nature through
biological transmission between susceptible
vertebrate hosts by blood-feeding arthropods
• Vertebrate infection occurs when the
infected arthropod takes a blood meal

10.  Flaviviridae – Japanese encephalitis – St.
Louis encephalitis – West Nile
 Togaviridae – Eastern equine encephalitis –
Western equine encephalitis
 Bunyaviridae – La Crosse encephalitis

11. • Flavivirus related to St. Louis encephalitis
• Most important cause of arboviral
encephalitis worldwide, with over 45,000
cases reported annually
• Transmitted by culex mosquito, which breeds
in rice fields
• Mosquitoes become infected by feeding on
domestic pigs and wild birds infected with
Japanese encephalitis virus. Infected
mosquitoes transmit virus to humans and
animals during the feeding process.

12.  Flavivirus
 Primary host – wild birds
 Principal arthropod vector – mosquitoes
 Geographic distribution - Africa, Middle
East, Western Asia, Europe, Australia, North
America, Central America

13.  Flavivirus
 Most common mosquitotransmitted human
pathogen in the US
 Leading cause of epidemic flaviviral
encephalitis

14. • Togavirus
• Caused by a virus transmitted to humans and
horses by the bite of an infected mosquito.
• 200 confirmed cases in the US 1964-present
• Human cases occur relatively infrequently,
largely because the primary transmission
cycle takes place in swamp areas where
populations tend to be limited.

15. • Togavirus
• Mosquito-borne
• 639 confirmed cases in the US since 1964
• Important cause of encephalitis in horses and
humans in North America, mainly in the
Western parts of the US and Canada

16. • Bunyavirus
• On average 75 cases per year reported
• Most cases occur in children under 16 years
old
• Zoonotic pathogen that cycles between the
daytime biting treehole mosquito, and
vertebrate amplifier hosts (tree squirrel) in
deciduous forest habitats
• 1963 – isolated in La Crosse, WI from the
brain of a child who died from encephalitis

17.  Herpes simplex virus type 1 (HSV-1), which is
responsible for cold sores
 HSV-2, which is responsible for genital herpes
 Varicella zoster virus, which causes chicken pox
and shingles
 Epstein-Barr virus, which causes mononucleosis
 Childhood viruses that can cause encephalitis
include:
 Measles (rubeola)
 German measles (rubella)
 Mumps

18.  Symptoms in newborns and younger infants
may not be as easy to recognize:
 Body stiffness
 Irritability and crying more often (these
symptoms may get worse when the baby is
picked up)
 Poor feeding
 Soft spot on the top of the head may bulge
out more
 Vomiting

19.  Loss of consciousness, poor responsiveness, stupor,
coma
 Muscle weakness or paralysis
 Seizures
 Severe headache
 Sudden change in mental functions:
 "Flat" mood, lack of mood, or mood that is
inappropriate for the situation
 Impaired judgment
 Inflexibility, extreme self-centeredness, inability to
make a decision, or withdrawal from social
interaction
 Less interest in daily activities
 Memory loss (amnesia), impaired short-term or long-
term memory

20.  Viral encephalitis is a serious medical condition.
 Although there are no specific medications to treat
it, people with symptoms are often given the
antiviral medication acyclovir (Zovirax).
 It works against herpes simplex and varicella-zoster
viruses.

21.  Acyclovir (Zovirax) -- treats encephalitis
caused by HSV, VZV,
 EBV Ganciclovir (Cytovene) -- treats
encephalitis caused by cytomegalovirus and
 HSV1 Anticonvulsant medications -- prevent
and treat seizures that may happen with
encephalitis

22.  The goals of treatment are to provide
supportive care (rest, nutrition, fluids) to
help the body fight the infection, and to
relieve symptoms.
 Reorientation and emotional support for
confused or delirious people may be helpful.
 Who can think of some examples of
treatments? Discuss and share.

23.  Eat antioxidant foods, including fruits (such as
blueberries, cherries, and tomatoes), and
vegetables (such as squash and bell peppers).
 Avoid refined foods, such as white breads, pastas,
and especially sugar.
 Eat fewer red meats and more lean meats, cold-
water fish, tofu (soy, if no allergy), or beans for
protein.
 Use healthy oils in foods, such as olive oil or
vegetable oil.
 Avoid caffeine, alcohol, and tobacco.
 Drink 6 - 8 glasses of filtered water daily.

24.  Give plenty of oral fluids.
 Maintain fluid balance
 Provide additional warmth by blanket if
needed
 Provide proper ventilation.

25.  Permanent brain damage may occur in
severe cases of encephalitis.
 It can affect:
 Hearing
 Memory
 Muscle control
 Sensation
 Speech
 Vision

26.  Over the past month, deaths of hundreds of
people in a fresh outbreak of encephalitis, in
the northern town of Gorakhpur U.P., have
increased.
 In recent monsoons, more than 500 have
died with 2 or 3 dying everyday just in
Gorakhpur U.P.
 Outbreak of encephalitis happen every year
due to monsoon rains.

28.  1. Further inpatient care:
Admission of the patient to the hospital, as
necessary.
• 2. Prevention
Immunization against JE is recommended for
those traveling into endemic areas during
high-risk times of year and this must be
explained to the patient

29.  Summarize what you have learned.
 Analyze the information provided and think
of ways to prevent encephalitis.
 Think of ways to help those who are
suffering
 Share this information with others.
 One of the best ways to master something is
to teach it to someone else.
 Be as safe, clean, and healthy as possible.

30. THANK YOU
Email ID- sombirkumar9195@gmail.com