What are viruses? Viruses are tiny microscopic infectious agent that replicates only inside the living cells of an organisms. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are classified in to two : DNA containing viruses, and RNA containing viruses. In this topic am talking about DNA VIRUSES, i hope you learn more about it.

1. Date:7/June/2022
Topic: DNA VIRUS
Presented By: Mr. Adnan Abdi

2. General Concept.
 A DNA virus is a virus that has a genome made of
deoxyribonucleic acid (DNA).They can be
divided between those that have two strands of
DNA in their genome, called double-stranded
DNA (dsDNA) viruses, and those that have one
strand of DNA in their genome, called single-
stranded DNA (ssDNA) viruses. dsDNA viruses
primarily belong to two Realms :Duplodnaviria
and varidnaviria and ssDNA viruses are almost
exclusively assigned to the realm:monodnaviria .

3. DNA Viruses are divided in to two major
Groups...
 Double Stranded DNA viruses {DsDNA}
1. Poxviridae
2. Hepadnaviridae
3. Herpesviridae
4. Human papillomavirus
 Single Stranded DNA Viruses {SsDNA}
1. Parvoviridae

4. Poxviridae...
Pox viruses are large enveloped viruses that
replacate in the cytoplasma and encode
proteins for DNA Replication and gene
expression. Diseases caused by pox viruses,
especially smallpox, have been known about
for centuries. One of the earliest suspected
cases is that of Egyptian pharaoh Ramses
V who is thought to have died from
smallpox.

5. Cont...
A century after Edward Jenner showed that
the less potent cow pox could be used to
effectively vaccinate against the more deadly
smallpox, a worldwide effort to vaccinate
everyone against smallpox began with the
ultimate goal to rid the world of the plague-
like epidemic. The last case of endemic
smallpox occurred in Somalia in 1977.
Extensive searches over two years detected
no further cases.

6. Hepadnaviridae...
Hepadnaviridae is a family of viruses. Humans,
apes, and birds serve as natural hosts. There
are currently 18 species in this family, divided
among 5 genera. Its best-known member is
hepatitis B virus.
Diseases associated with this family
include: liver infections, such as hepatitis,
hepatocellular carcinomas and cirrhosis.

7. Cont...
Hepatitis B is an infectious disease caused by
the hepatitis B virus (HBV) that affects
the liver; it is a type of viral hepatitis. It can
cause both acute and chronic infection. The
virus is transmitted by exposure to
infectious blood or body fluids. In areas
where the disease is common, infection
around the time of birth or from contact with
other people's blood during childhood are the
most frequent methods by which hepatitis B
is acquired.

8. Cont...
Hepatitis B infection has been preventable
by vaccination since 1982. The World
Health Organization (WHO) recommends
vaccination in the first day of life if
possible. Two or three more vaccine doses
are required at a later time for full effect.
This vaccine is about 95% effective in
preventing infection. About 180 countries
gave the vaccine as part of national
programs as of 2006.

9. Herpesviridae...
Herpesviridae is the name of a family
of enveloped, double-stranded DNA
viruses with relatively large complex
genomes. They replicate in the nucleus
of a wide range of vertebrate hosts,
including eight varieties isolated in
humans, several each in horses, cattle,
mice, pigs, chickens, turtles, lizards,
fish, and even in some invertebrates,
such as oysters.

10. Human Herpes Viruses {HHV}
 Eight human Herpes virus species are known
1. Herpes Simplex virus type 1 {HSV-1}
2. Herpes simplex virus type 2 {HSV-2}
3. Varicella zoster virus {VZV}
4. Cytomegalovirus {CMV}
5. Epstein-Barr virus {EBV}
6. Human Herpes virus type 6 {HHV-6}
7. Human Herpes virus type 7 {HHV-7}
8. Human Herpes virus type 8 {HHV-8}

12. Human papillomavirus (HPV)
Human papillomavirus (HPV) is a viral
infection that’s passed between people
through skin-to-skin contact. There are over
100 varieties of HPV, more than 40 Trusted
Source of which are passed through sexual
contact and can affect your genitals, mouth,
or throat. The virus that causes HPV infection
is transmitted through skin-to-skin contact.
Most people get a genital HPV infection
through direct sexual contact.

13. Cont...
Many people have HPV and don’t even know
it, which means you can still contract it even
if your partner doesn’t have any symptoms.
It’s also possible to have multiple types of
HPV. In rare cases, a mother who has HPV
can transmit the virus to her baby during
delivery. When this happens, the child may
develop a condition called recurrent
respiratory papillomatosis where they
develop HPV-related warts inside their throat
or airways.

14. Cont...
Most cases of HPV go away on their
own, so there’s no treatment for the
infection itself. Instead, your doctor
will likely want to have you come in
for repeat testing in a year to see if
the HPV infection persists and if any
cell changes have developed that need
further follow-up.

15. Parvoviridae.
What is parvovirus? What is a parvovirus infection (parvovirus
B19)?
The parvovirus in humans is different than the one by the same name found in
dogs and cats. Humans get a different type: B19. Parvovirus B19 is a common
infectious disease that is spread from person to person and most often results
in no or very mild symptoms. The virus sometimes targets the cells that mature
into red blood cells. Infection causes a temporary stoppage of the production of
these cells. The effect of this stoppage is only apparent in individuals who don’t
produce normal red blood cells.

16. Cont...
The parvovirus causes fifth disease also known
as “slapped cheek” disease, which is very
common in school-aged children
How is a parvovirus infection spread?
Human parvovirus is present in the nasal mucus,
spit or saliva. The virus can be spread through
airborne droplets when an infected person
coughs or sneezes. It may also spread through
blood or contaminated blood products.
Pregnant women who have been infected with
parvovirus can spread the virus to the fetus
through the placenta.