viral diseases of human

1. HUMAN DISEASES CAUSED
BY VIRUSES

2. • When a cell is infected with a virus several effects
may be seen.
• Many viruses cause no harm or disease but some
may attack certain cells and multiply within them.
• Once mature the daughter viruses break the cell
and spread elsewhere.
• If the host immunity operates effectively the virus
infected cell may be killed by the host.

3. • Spread of virus occurs through different routes:-
Skin contact- HPV (warts)
Animal bite – rabies
Sexually – herpes 1 & 2 , hepatitis B
• A viral disease occurs when an organism’s body is
invaded by pathogenic viruses and infectious viral
particles (virions) attach to and enter susceptible
cells.

4. • Common viral diseases include :-
Chickenpox
Flu (influenza )
Herpes
HIV/AIDS
Infectious mononucleosis
Mumps , measles and rubella
Rabies

5. ACQUIRED IMMUNO DEFICIENCY
SYNDROME
• AIDS is a spectrum of conditions caused by infection
with the human immunodeficiency virus.
• Following initial infection , a person may experience a
brief period of influenza like illness.
• This is followed by a prolonged period without
symptoms.
• As infection progresses , it interfere more and more
with the immune system.

6. •SYMPTOMS
a) Acute infection
oInitial period.
oIndividuals develop an influenza like illness or a
mononucleosis like illness 2-4 weeks post
exposure.
oSymptoms include fever , large tender lymph
nodes , throat inflammation , rash , head ache ,
sores of mouth.

7. b) Clinical latency
oAsymptomatic / chronic HIV
oNear the end of this stage people experience fever ,
weight loss , gastrointestinal problems and muscle pain.
c) Acquired immunodeficiency syndrome
oIt is defined in terms of either a CD4+ T cell count
below 200μL or occurrence of specific diseases in
association with HIV infection.
oThe most common initial conditions that alert the
presence are pnemocystic pneumonia ,oesophageal
candidiasis .

9. •VIROLOGY
oHIV is a retrovirus that
primarily infects
components of human
immune system such as
CD4+ T cells ,
macrophages and
dendritic cells.
oIt directly and indirectly
destroys CD4+ T cells.

10. •TRANSMISSION
Unprotected sexual intercourse
Contaminated blood transfusions
Hypodermic needles
From mother to child during pregnancy ,
delivery or breast feeding.
Body fluids like saliva tears do not transmit HIV.

11. •TREATMENT
There is currently no cure or effective HIV vaccine.
Treatment consists of highly active antiretroviral
therapy (HAART) which slows down the
progression.
HAART:-
• Combinations of at least 3 medications.
• A Non-nucleoside reverse transcriptase inhibitor
(NNRTI)and two nucleoside analogue reverse
transcriptase inibitor (NRTIs).

12. SMALLPOX
• Infectious disease caused by either of two virus
variants ,Variola major and Variola minor.
• Infection is focused in small blood vessels of the
skin and in the mouth and throat.
• In the skin it results in a characteristic
maculopapular rash and later raised fluid- filled
blisters.

13. •SIGNS AND SYMPTOMS
a) Ordinary
• Macules(rash) raised papules fluid filled
vesicles  pustules Mature fluid leaks
deflate & dry up depigmented scars.
b) Modified
• Less severe
• Lesions fewer and evolve more quickly and may
not show typical characteristics of smallpox.

14. c) Malignant
• Lesions remains almost flush with the skin.
• Rash on tongue and palate is extensive.
• Vesicles contain little fluid.
d) Hemorrhagic
• Severe form.
• Extensive bleeding into skin , mucous membrane
and gastrointestinal tracts.
• Occurrence is mostly in adults.

16. •VIROLOGY
oIt is caused by the
infection with variola
virus.
oVirus infects only
humans in nature.

17. •TRANSMISSION
oInhalation of airborne variola virus.
oFace-to-face contact with infected person.
oDirect contact with infected bodily fluids and
contaminated objects.
•TREATMENT
oVaccination within 3 days of exposure prevent or
lessen severity.
oWound care , infection control , fluid-therapy.
oAnti-viral drugcidofovir (therapeutic agent).

18. RABIES
• A viral disease that causes acute inflammation of
brain in humans and warm-blooded animals.
• Caused by lyssaviruses including rabies virus and
Australian bat lyssavirus.
• The virus travels to the brain following peripheral
nerves.
• The disease can only be diagnosed after the start of
symptoms.

19. •SYMPTOMS
oViolent movements
oUncontrolled excitement
oFear of water
oInability to move body parts
oConfusion
oLoss of consciousness

20. • HYDROPHOBIA
oSet of symptoms in the later stages of disease.
oThe person has difficulty swallowing , shows
panic when presented with liquids to drink and
can not quench thirst.
oSalivary production is greatly increased.
oAttempts to drink causes painful spasms of the
muscles in throat and larynx.

21. •TRANSMISSION
oMost animals can be infected by the virus and
can transmit it to humans.
oInfected bats, monkeys, foxes, cattle, dogs and
cats present the greatest risk to humans.
oThe route of infection is usually by a bite.
oTransmission between humans is rare.

22. •TREATMENT
oThoroughly washing the wound as soon as possible
with soap and water for 5 minutes reduce the
number of viral particles.
oPovidone-iodine or alcohol is recommended further.
oOne dose of human rabies immunoglobulin(HRIG)
and four doses of rabies vaccine over a 14-day
period.

23. MEASLES
• Also known as morbilli, rubeola , red measles .
• Highly contagious disease caused by measles
virus.
• It is an airborne disease which spreads through
coughs and sneezes.
• It may also be spread through contact with saliva
or nasal secretions.

24. •SYMPTOMS
oInitial symptoms include fever, cough, runny
nose and red eyes.
oAfter 2-3 days small white spots may form inside
the mouth known as Koplik’s spots.
oRed flat rashes starts on the face and then
spreads to rest of the body.
oComplications include diarrhea, blindness,
inflammation of the brain and pneumonia.

25. 4 day measles rash

26. •TREATMENT
oAntibiotics for pneumonia, sinusitis and bronchitis.
oIbuprofen or paracetamol for fever and pain.
oFast acting medications to dilate airways for
coughing.
oUse of vit A during treatment to decrease the risk
of blindness.

27. SWINE FLU
• Swine influenza, also called pig influenza, swine
flu, hog flu and pig flu, is an infection caused by
any one of several types of swine influenza viruses.
• SIV strains include influenza C and the subtypes
of influenza A known as H1N1, H1N2,
H2N1, H3N1, H3N2, and H2N3.
• Swine influenza virus is common throughout pig
populations worldwide.

28. H1N1 influenza virus

29. •SYMPTOMS
oSymptoms include fever, sore throat, watery eyes,
body aches, shortness of breath, headache, weight
loss, sneezing, abdominal pain, lack of appetite
and fatigue.
oThe most common cause of death is respiratory
failure.
oOther causes of death are pneumonia high
fever, dehydration, electrolyte
imbalance and kidney failure.

30. •TREATMENT
oAntiviral drugs can make the illness milder and
make the patient feel better faster.
oBeside antivirals, supportive care at home or in a
hospital focuses on controlling fevers, relieving pain
and maintaining fluid balance, as well as identifying
and treating any secondary infections or other
medical problems.

31. BIRD FLU
• Bird flu, or avian influenza, is a viral infection spread from
bird to bird.
• H5N1 is a highly pathogenic avian influenza (HPAI) virus.
• It is deadly to humans and to other mammals that catch
the virus from birds.
• People catch bird flu by close contact with birds or bird
droppings.

32. •SYMPTOMS
ofever (above 38 C or 100.4 F),
ocough sore throat,
omuscle aches
onausea
ovomiting
odiarrhea
oheadache
ojoint pain
oinsomnia
oeye infections.

33. •TREATMENT
oresting
odrinking plenty of fluids and eating healthily.
otaking medication to help treat fever and pain,
such as aspirin and paracetamol.
oOseltamivir , Zanamivir and Peramivir help reduce
the severity of the condition, prevent
complications and improve the chances of
survival.

34. SEVERE ACUTE RESPIRATORY
SYNDROME (SARS)
• Viral respiratory disease caused
by corona virus.
• Infection causes acute
respiratory distress.
• Lead to pneumonia.
• Transmission is through infected
droplets spraying to air by
coughing or sneezing. SARS corona virus

36. •TREATMENT
oAntibiotics to treat bacteria that cause pneumonia.
oHigh doses of steroids to reduce swelling in lungs.
oOxygen , breathing support or chest therapy.