Viral Diseases

Viral Diseases
HIV/ AIDS
• HIV is a virus that attacks the immune system, which is our body’s
natural defence against illness. The virus destroys a type of white
blood cell in the immune system called a T-helper cell, and makes
copies of itself inside these cells. T-helper cells are also referred to
as CD4 cells.
• As HIV destroys more CD4 cells and makes more copies of itself, it
gradually breaks down a person’s immune system. This means
someone living with HIV, who is not receiving treatment, will find it
harder and harder to fight off infections and diseases.
• If HIV is left untreated, it may take up to 10 or 15 years for the
immune system to be so severely damaged it can no longer defend
itself at all. However, the speed HIV progresses will vary depending
on age, health and background.
Basic facts about HIV
• HIV stands for human immunodeficiency virus.
• There is effective antiretroviral treatment available
so people with HIV can live a normal, healthy life.
• The earlier HIV is diagnosed, the sooner treatment
can start – leading to better long term health. So
regular testing for HIV is important.
• HIV is found in semen, blood, vaginal and anal fluids,
and breast milk.
• HIV cannot be transmitted through sweat, saliva or
urine.
Rotaviruses
• Rotavirus infections are the leading cause of severe
diarrheal illness in children. The CDC reports that
roughly 55,000 children are hospitalized with
rotavirus each year in the U.S. More than 500,000
children die annually of the illness worldwide.
Rotavirus symptoms include abdominal pain,
vomiting and watery diarrhea, which persist for
three to eight days. Adults are susceptible to
rotavirus gastroenteritis, but the illness is typically
much milder than it is in young children.
Herpes Simplex Viruses
• Herpes simplex viruses are common worldwide. Two
versions of the virus, herpes simplex virus 1 and 2, cause
a wide spectrum of human infections. Genital herpes,
cold sores, herpes eye infections, herpes encephalitis
(brain infection) and congenital herpes are common HSV
infections. A distinguishing characteristic of HSV
infection is the cycle of dormancy and reactivation. Once
infected with HSV, the virus remains in the body. During
inactive periods, HSV remains dormant in nerve cells.
The viruses, however, are capable of reactivating and
causing another round of symptoms if triggered.
Influenza Viruses
• Humans commonly contract influenza viruses type A and B,
which cause seasonal flu. Influenza type A typically causes a
more severe form of the illness than does type B. Only
influenza type A causes pandemic influenza outbreaks. The
unpredictability, capacity for pervasiveness, and potential for
lethality of influenza viruses was demonstrated during the
global influenza pandemic of 1918, known as the Spanish flu.
In a 2006 article published in the CDC journal “Emerging
Infectious Diseases,” Drs.Taubenberger and Morens point out
that one-third of the worldwide population was infected
during the 1918 flu pandemic, which caused an estimated 50
million to 100 million deaths.
Human Papillomaviruses
• There are more than 100 types of human papillomaviruses.
They cause benign epithelial skin growths better known as
warts. Plantar warts commonly occur on the soles of the feet.
Common warts occur on the hands or feet. Plane warts are
most common in children and usually occur on the neck, face
or hands. Of greatest public health concern are sexually
transmitted genital warts caused by 30 different types of HPV.
The CDC reports 20 million Americans are currently infected
with genital warts; 6 million new infections occur annually. A
group of high-risk genital HPVs can lead to cervical cancer.
Vaccines that protect against infection with some—but not all
—of the high-risk HPVs are currently available.
Chikungunya Virus
Symptoms
• Most people infected with chikungunya virus will develop some symptoms.
• Symptoms usually begin 3–7 days after being bitten by an infected
mosquito.
• The most common symptoms are fever and joint pain.
• Other symptoms may include headache, muscle pain, joint swelling, or
rash.
• Chikungunya disease does not often result in death, but the symptoms can
be severe and disabling.
• Most patients feel better within a week. In some people, the joint pain
may persist for months.
• People at risk for more severe disease include newborns infected around
the time of birth, older adults (≥65 years), and people with medical
conditions such as high blood pressure, diabetes, or heart disease.
• Once a person has been infected, he or she is likely to be protected from
future infections.
Treatment
• There is no vaccine to prevent or medicine to treat chikungunya
virus.
• Treat the symptoms:
– Get plenty of rest.
– Drink fluids to prevent dehydration.
– Take medicine such as acetaminophen (Tylenol®) or paracetamol to
reduce fever and pain.
– Do not take aspirin and other non-steroidal anti-inflammatory drugs
(NSAIDS until dengue can be ruled out to reduce the risk of bleeding).
– If you are taking medicine for another medical condition, talk to your
healthcare provider before taking additional medication.
• If you have chikungunya, prevent mosquito bites for the first week
of your illness.
– During the first week of infection, chikungunya virus can be found in the
blood and passed from an infected person to a mosquito through
mosquito bites.
– An infected mosquito can then spread the virus to other people.
Dengue Fever
• Dengue fever is transmitted by the bite of an
Aedes mosquito infected with a dengue virus.
The mosquito becomes infected when it bites
a person with dengue virus in their blood. It
can’t be spread directly from one person to
another person.
Symptoms of Dengue
• Sudden, high fever
• Severe headaches
• Pain behind the eyes
• Severe joint and muscle pain
• Fatigue
• Nausea
• Vomiting
• Skin rash, which appears two to five days after the
onset of fever
• Mild bleeding (such a nose bleed, bleeding gums, or
easy bruising)
Treatment for Dengue Fever
There is no specific medicine to treat dengue

infection. If you think you may have dengue fever,
you should use pain relievers
with acetaminophen and avoid medicines
with aspirin, which could worsen bleeding. You
should also rest, drink plenty of fluids, and see
your doctor. If you start to feel worse in the first
24 hours after your fever goes down, you should
get to a hospital immediately to be checked for
complications.
Preventing Dengue Fever
• There is no vaccine to prevent dengue fever.

The best way to prevent the disease is to
prevent bites by infected mosquitoes,
particularly if you are living in or traveling to a
tropical area. This involves protecting yourself
and making efforts to keep the mosquito
population down.
Viruses and Cancer
• Viruses are capable of altering growth properties
of human cells they infect by triggering oncogene
expression.
– Association between hepatitis B infections and liver
cancer
– Cervical cancer linked to certain strains of HPV
(human papilomaviruses)
– 15% of all cancers worldwide
Others……
• Pneumonia
• Measels
• Hepatitis C
• Meningitis
• Viral infection
• Fever
• Common cold
M/A of Antiviral drugs
1. Inactivate extracellular virus particles.

2. Prevent viral attachment and/or entry.
3. Prevent replication of the viral genome.
4. Prevent synthesis of specific viral protein(s).
5. Prevent assembly or release of new infectious
virions.
Viruses in biological studies
• Viruses have been used extensively in molecular
and cellular biology studies. These viruses
provide the advantage of being simple systems
that can be used to manipulate and investigate
the functions of cells.Viruses have been used
extensively in genetics research and
understanding of the genes and DNA replication,
transcription, RNA formation, translation,
protein formation and basics of immunology.
• Viruses in medicine
• Viruses are being used as vectors or carriers that take the required
material for treatment of a disease to various target cells. They have been
studied extensively in management of inherited diseases and genetic
engineering as well as cancers.
• Viruses in bacteriophage therapy
• These are highly speciﬁc viruses that can target, infect, and (if correctly
selected) destroy pathogenic bacteria. Bacteriophages are believed to be
the most numerous type of viruses accounting for the majority of the
viruses present on Earth. These are basic tools in molecular biology. They
have been researched for their use in therapy.
• Viruses in nanotechnology
• Nanotechnology deals with microscopic particles. These have various uses
in biology and medicine and nanotechnology has been used in genetic
engineering. Viruses can be used as carriers for genetically modified
sequences of genomes to the host cells.
• Viruses in weapons and biological warfare
• Viruses may be tiny but have the capacity to cause death and devastation to
large populations in epidemics and pandemics. This has led to the concern
that viruses could be used for biological warfare.
• Viruses in agriculture
• Modification and genetic engineering methods can be used to make
modified genomes that can be carried into plants and animals by viruses
acting as vectors or vehicles. This method can lead to more productive
transgenic animals and plants.
• Viruses and vaccines
• Viruses have been used since the time of Edward Jenner in vaccines. Jenner
used cow pox viruses to inoculate people against small pox infection.
• Vaccines against polio, measles, chicken pox etc. use live and weakened
viruses causing the disease or dead virus particles. These, when introduced
into an healthy individual, help the immune system to recognise and mount
an immunity against the virus. The body remembers the organism and
attacks it in case of a later infection thus preventing the disease.
• Vaccines for cancer prevention
• Vaccines for hepatitis B and those for human papillomavirus
protect against liver and cervical cancer respectively. Both use
selected proteins of the virus (subunit vaccines).
• Virus-directed enzyme prodrug therapy (VDEPT)
• This is a therapy when the target cells are inserted with an
enzyme that can activate an inactive a precursor or inactive
form of a cytotoxic drug that is administered systemically. Thus,
the active, cytotoxic form of the drug is only produced where
the relevant enzyme is present and active.
• For example, an adenovirus expressing the thymidine kinase
(TK) enzyme of herpes simplex virus can be combined with
systemic administration of ganciclovir, which is converted by the
TK to its active form only in cells where this enzyme is present.
This is used in HIV treatment.
• Viruses and biological pest control
• Viruses can also be used to control damaging
pests. Traditionally this has been used in
agriculture, but applications exist in the
control of agents important to human health
as well.
• The types of agents used for this purpose may
prey on the target species, may be parasites
on the target pests, be pathogens or cause
disease in the target species or may be
competing species.

Viral Diseases

Uploaded by

Copyright:

Available Formats

Viral Diseases

Uploaded by

Document Information

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Viral Diseases

Uploaded by

Copyright:

Available Formats

Viral Diseases

There is no specific medicine to treat dengue

• There is no vaccine to prevent dengue fever.

1. Inactivate extracellular virus particles.

You might also like