This document provides information on hepadnaviruses and hepatitis B virus (HBV). It discusses the morphology and structure of HBV particles, modes of transmission, infection and associated diseases, laboratory diagnosis, immunization, treatment, and prevention. HBV is a partially double-stranded DNA virus that infects liver cells and can cause both acute and chronic liver disease. It is transmitted through contact with infected blood and bodily fluids.

1. HEPADNAVIRUS
Clinical Microbiologist Mr. Manoj Mehta, Civil Service Hospital Of Nepal

2. Hepadnaviruses (from the Greek words “hepato” meaning liver and
“DNA virus”) are a family of viruses that primarily infect liver cells.
The best-known member of this family is the hepatitis B virus
(HBV)
Hepatitis B virus (HBV), also known as hepadnavirus, is a partially
double-stranded DNA virus that infects the liver and can cause both
acute and chronic liver disease.
These viruses have small, enveloped, spherical virions (virus
particles) that measure approximately 40–48 nanometers in diameter
HBV is a complex 42 nm double-shelled particle consist of an outer
envelope & an inner core
HEPATITIS B VIRUS

3. The outer surface or envelope of virus contains hepatitis B surface
antigen (HBsAg).
The core of the virus consists of an icosahedral 27nm nucleocapsid,
which contains Hepatitis B core antigen (HBcAg).
Inside the core is the genome, a circular dsDNA & a DNA polymerase.
HBV, antigenically, have been divided into 3 types of particles as:-
HBsAg – Hepatitis B Surface Antigen a.k.a. Australia antigen.
HBcAg – Hepatitis B core Antigen a.k.a. Core antigen.
HBeAg – Hepatitis B early Antigen a.k.a. Early antigen.
MORPHOLOGY OF HEPATITIS B VIRUS

4. MORPHOLOGY OF HEPATITIS B VIRUS

5. HBV is a blood-borne virus and the infection is transmitted by
Parenteral, Sexual & Perinatal route.
Parenteral Route: Blood, Saliva, Breast Milk, Semen, Vaginal
Secretions, Urine, Bile & Feces.
Sexual contact: Unprotected sex with an infected person.
Sharing needles: Contaminated needles and syringes.
Accidental needle sticks: A concern for healthcare workers.
Mother-to-child transmission: Infected pregnant women can pass
the virus to their babies during childbirth.
MODE OF TRANSMISSION

6. HBV primarily infects liver cells
 Liver cirrhosis, hepatocellular carcinoma & chronic
hepatitis are common
INFECTION AND DISEASES

7. The clinical features HBV are similar to that of the HAV
The incubation period is long, about 1-6 months
Yellowing of the skin and eyes
Loss of appetite
Nausea and vomiting
Weakness and fatigue
Abdominal pain
Dark urine
Light-colored stools
SIGNS AND SYMPTOMS

8. HBV infection can be carried out by detection of hepatitis B
antigens & antibodies
Detected by sensitive tests like ELISA & RIA.
 Hbcag is not detectable in the serum but can be demonstrated in
liver cells by immunofluorescence.
The DNA levels of HBV can also be detected in serum by PCR.
LABORATORY DIAGNOSIS

9. Surgeons,
Nurse
Phlebotomists
 ™
Paramedical workers
Sex workers especially homosexual males
 Recipients of blood transfusion
Organ transplantation
 Drug addicts
0.00001 ml of blood can be infectious „chance of transmission of HBV
following a contaminated needle prick
HIGH-RISK GROUPS

10. Safe injection practices: Use of the disposable syringes and
needles
Safe aseptic surgical practices
Health education
Screening for HbsAg & HbeAg: In blood donors, semen and
organ donors
Safe sex practices : Using condoms, avoiding multiple sex
partners
PROPHYLAXIS OF HEPATITIS B VIRUS

11. Intramuscular administration of the hepatitis b immunoglobulin
(HBIG) as soon as possible after any accidental exposure to HBV
infection,
Three doses of hepatitis b vaccine at 0, 1 & 6 months are administered
intramuscularly provides immunity against HBV for many years.
Combined immunization with HBIG and vaccine is more efficacious
than HBIG alone.
HBIG is recommended for neonates born to HBV infected mother,
where a single injection of 0.5 ml of HBIG is given to the neonate
immediately after the birth, followed by full course of vaccine (the first
dose being given within 12 hours of birth)
IMMUNIZATION

12. No specific antiviral treatment is available.
There is no cure for HBV, but there are treatments that can help
to slow the progression of the disease and reduce the risk of
complications.
Treatment options include antiviral medications,interferon
therapy, and liver transplantation.
TREATMENT OF HEPAITIST B VIRUS

13. A retrovirus is a type of virus that uses RNA as its genetic material.
Retroviruses are unique among viruses in that they use reverse
transcriptase, an enzyme that converts RNA into DNA, to create a
DNA copy of their genome.
This DNA copy is then integrated into the host cell's genome, where it
can be transcribed and translated to produce new viral proteins.
Retroviruses are responsible for a number of diseases in humans and
animals, including HIV/AIDS, leukemia, and lymphoma.
RETROVIRUS

14. Retroviruses are enveloped viruses, meaning that they have a lipid
membrane surrounding their protein coat.
Transmitted from one host to another through contact with infected
blood, semen, or breast milk.
Some examples of retroviruses
 Human t-lymphotropic virus-1 (HTLV-1), which causes adult t-cell
leukemia
Human immunodeficiency virus (HIV), which causes AIDS.
Human t-lymphotropic virus-3 (htlv-3), which causes a rare form of
leukemia.
RETROVIRUS

15. Parvovirus is a genus of small, single-stranded DNA viruses that
infect vertebrates.
 Parvoviruses are classified into two subgenera: parvovirus a and
parvovirus b.
Parvovirus a includes the human parvovirus b19, which causes fifth
disease, and the canine parvovirus, which causes parvovirus enteritis
in dogs.
The parvovirus causes fifth disease also known as “slapped cheek”
disease, which is very common in school-aged children.
PARVOVIRUS

16. Morphology:
 Extremely small viruses (18-26 nm in diameter).
 Nonenveloped, icosahedral capsid.
 Single-stranded DNA genome (4000-6000 bases in length).
 Negative-strand DNA.
 Encodes several proteins, including structural and
nonstructural proteins
MORPHOLOGY OF PARVOVIRUS

17. 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 people with parvovirus can spread the virus to the fetus
through the placenta.
MODE OF TRANSMISSION

18. Swollen and/or painful joints, Arthritis
Fatigue.
Low-grade fever.
Headache.
Upset stomach.
Gloves and socks syndrome
Fifth disease, also known as “Slapped Cheek” disease.
SIGNS AND SYMPTOMS

19. SIGNS AND SYMPTOMS

20. Wash your hands often with soap and water
Cover your mouth and nose when you cough or sneeze
Avoid touching your eyes, nose, and mouth
Avoid close contact with people who are sick
Stay home when you are sick
PREVENTION AND CONTROL

21. Parvovirus is usually self-limiting
No treatment is necessary.
However, you may want to try the following:
Take acetaminophen (like tylenol®) to relieve your
headache and fever.
Take nonsteroidal anti-inflammatory drugs like ibuprofen
(like advil®) for your joint pain and swelling.
Drink plenty of fluids and get enough rest.

22. Enzyme-linked immunosorbent assay (ELISA):Detects
antibodies against the parvovirus B19.
Hemagglutination assay: Confirms the presence of viruses
in the sample.
Electron microscopy: Detects the presence of antigen in the
sample.
Polymerase chain reaction (PCR): Detects the DNA of the
virus
LABORATORY DIAGNOSIS

23. Bunyaviruses are a diverse group of negative-sense single-
stranded RNA viruses.
They are found in various parts of the world.
Most bunyaviruses are vector-borne
Transmitted by arthropods, such as mosquitoes, ticks, and
sandflies.
BUNYAVIRUSES

24. MODE OF TRANSMISSION
Transmitted by arthropods, such as mosquitoes, ticks, and sandflies

25. Fever
Headache
 Muscle aches
Joint pain
Fatigue
Rash
In severe cases,cause encephalitis, meningitis, hemorrhagic
fever.
SIGNS AND SYMPTOMS

26. There are no specific antiviral treatments.
Some antiviral drugs may be effective against certain
viruses.
Avoiding contact with infected arthropods,
 Using insect repellent,
 Wearing protective clothing,
Taking precautions to reduce the risk of bites.
PREVENTION AND CONTROL

27. Rhabdoviruses are a diverse group of negative-sense,
single-stranded RNA viruses
 Infect a wide range of hosts, including humans, animals,
and plants.
 They are characterized by their bullet-shaped morphology
Cause a variety of diseases, including rabies, ebola, and
marburg virus infections.

28. Some notable examples of rhabdoviruses include:
Rabies virus: causes rabies, a fatal neurological disease in
humans and animals.
Marburg virus: causes Marburg virus disease, a severe
hemorrhagic fever.
Ebola virus: causes Ebola virus disease, another severe
hemorrhagic fever.
Vesicular stomatitis virus: causes vesicular stomatitis, a
disease that affects livestock.

29. Rabies is a global disease,
 but it is most common in Asia and Africa
Rabies is a zoonotic disease,
meaning that it can be transmitted from animals to humans.
The most common source of rabies infection in humans is
dogs,
 but the virus can also be transmitted by other animals,
such as cats, raccoons, skunks, and bats

30. The rabies virus is a member of the Lyssavirus genus of the
Rhabdoviridae family.
It is a single-stranded RNA virus with a bullet-shaped
morphology.
 The virus is enveloped and has a glycoprotein spike that
mediates attachment to host cells
MORPHOLOGY OF RABIES VIRUS

31. Transmitted by the bite of an infected animal.
The virus is present in the saliva of infected animals and
can be transmitted through contact with broken skin or
mucous membranes.
MODE OF TRANSMISSION

32. Fever
Headache
Confusion
Difficulty swallowing
Excessive salivation
Fear brought on by attempts to drink fluids because of
difficulty swallowing water
Fear brought on by air blown on the face
Partial paralysis
SIGNS AND SYMPTOMS

33. Regular rabies vaccinations for pets and domestic animals
Bans or restrictions on the import of animals from certain
countries
Widespread vaccinations of humans in some areas
Educational information and awareness
Enhanced access to medical care to people who receive
bites
Prevented by prompt vaccination after exposure to the
virus
PREVENTION AND CONTROL

34. There’s no approved treatment for rabies once you have
symptoms

35. Reoviruses are a diverse group of non-enveloped, single-
stranded RNA viruses that belong to the family reoviridae.
They are found in a wide variety of hosts, including
humans, animals, and plants.
Reoviruses are typically transmitted through contact with
contaminated food or water, or through inhalation of
aerosolized droplets
REOVIRUSES

36. Transmitted through contact with contaminated food or
water, or through inhalation of aerosolized droplets.
MODE OF TRANSMISSION

37. Rotaviruses are a group of highly contagious viruses that
cause gastroenteritis, a condition characterized by
inflammation of the stomach and intestines.
They are the leading cause of severe diarrhea among
children under the age of five worldwide

38. Rotaviruses are transmitted through the fecal-oral route,
meaning that they are spread when someone ingests food or
water that has been contaminated with the feces of an infected
person.
 The virus can survive for several days on surfaces and
objects, making it easy to spread

39. Symptoms of rotavirus infection typically develop within 2-3
days of exposure to the virus and can include:
Severe diarrhea
Vomiting
Fever
Abdominal pain
Dehydration
Loss of appetite
Lethargy
SIGNS AND SYMPTOMS

40. Rotavirus infection is a preventable disease, and vaccination
is the best way to protect children from this potentially serious
illness.
There are two vaccines available to prevent rotavirus
infection: rotarix and rotateq.
Both vaccines are given orally and are highly effective in
preventing severe rotavirus disease.
The vaccines are recommended for all children as part of
their routine immunization schedule.
PREVENTION AND CONTROL

41. Treatment for rotavirus infection is supportive and involves
replacing lost fluids and electrolytes to prevent dehydration.
 In severe cases, hospitalization may be necessary.

42. THANK YOU