Kaposi's Sarcoma

Kaposi's Sarcoma

Also called: KS
Kaposi's sarcoma is a cancer that causes patches of abnormal tissue to grow under the skin, in the lining of the mouth, nose, and throat or in other organs. The patches are usually red or purple and are made of cancer cells and blood cells. The red and purples patches often cause no symptoms, though they may be painful. If the cancer spreads to the digestive tract or lungs, bleeding can result. Lung tumors can make breathing hard.
Before the AIDS epidemic, KS usually developed slowly. In AIDS patients, though, the disease moves quickly. Treatment depends on where the lesions are and how bad they are. Treatment for the AIDS virus itself can shrink the lesions. However, treating KS does not improve survival from AIDS itself.


Diagnosis/Symptoms

Signs and symptoms of Kaposi sarcoma:

The first sign of Kaposi sarcoma (KS) is usually the development of skin lesions. Typical lesions begin as flat or slightly raised colored spots. Sometimes they develop under the skin and do not have any unusual coloring. The lesions can develop anywhere on the body, but most often they arise on the legs, nose (especially the tip), the feet, outside parts of the ears, mouth, or genitals. In time the lesions progress to larger nodules that range in color from pink or red to blue, purple, or brown. In dark-skinned people, the lesions may be dark brown or black. Sometimes a greenish "halo" appears around the lesion. Usually the lesions are not tender or sore.

MERRY MERRY CHRISTMAS!!

2008 CHRISTMAS IS KNOCKING ON OUR DOORS!!

HOHOHO!! SANTA CLAUS IS COMING TO TOWN!!

HE GIVES US PRESENTS!!

BUT WE WILL GIVE YOU....

BREAKING NEWS!!



TWINS BORN TODAY ON THIS SPECIAL OCCASION!!
Auckland's equine twins, Holly and Rio were born around dawn. Both are healthy. Blessings to them and their mum(:

Talking about horses, we came across an interesting article and would like to share it with you!! Two German virologists actually say a virus which kills horses could also help to trigger mental illness in human beings.

KILLER VIRUS COULD CAUSE HUMAN DEPRESSION??!!

The specialists say borna disease, which attacks animals' brains, could be the cause of more than half the cases of clinical depression in humans.

In 1994, Ludwig and Bode found the borna virus in the blood of people with clinical depression.

In 1996 they managed to extract it from three mentally ill patients and use it to infect rabbits, which became sluggish and withdrawn.

In January, they reported that the drug amantadine, which is used to treat parkinson's disease, stopped the borna virus from multiplying in human brain cells.

The men stress that borna disease is unlikely to be the sole cause of clinical depression, but have set up a trial in Hanover to compare amantadine with a placebo in 40 clinically depressed patients.

Juan de la Torre, a virologist at the Scripps Research Insti tute in La Jolla, California: "You have serious investigators who think the whole thing is bogus; there are others who think that the virus does cause neuropsychiatric disorders. Then there are people like me, and quite a few others, who say well, it's really too early to say anything.''

Since 1985 studies have reported borna virus antibodies in anywhere from four to 40 percent of patients with mental illnesses who were under observation.

Borna, first discovered in horses, was later found to naturally infect sheep, cattle, cats and ostriches. Scientists artificially infected rats and other animals and found the virus settled in parts of the brain that regulate basic emotions.

Anyway, we would like to wish everyone a joyful and blessful MERRY CHRISTMAS!! ENJOY(: CHEERS!!

Flaviviviridae

The word “flavi” is latin for yellow because one of the most famous flaviviruses is Yellow Fever Virus. Viruses in the flavivirus family are all single-stranded RNA viruses with linear non-segmented genomes. Viruses in this family are considered positive (+) sense because proteins are made directly from the template strand of RNA which is present in the viral capsid. Production of a complementary RNA strand is not necessary for viruses in this family to produce protein. The genome of these viruses are on average 11,000 nucleotides long - they encode around 10 genes. The capsid of viruses in this family are icosahedral shaped and around the viral capsid a spherical shaped envelope is present. The capsids are approximately 40-50 nanometers in diameter and are composed of a single type of capsid protein.

Replication:

Replication of Flaviviruses takes place in the cytoplasm. Flavivirus cannot replicate in the nucleus because, like most other RNA viruses, it uses the host cell's RNA dependant RNA polymerase to replicate. Primarily, the virus will make a full length copy of the complementary, minus strand genome. This complementary genome then serves as a template strand for further replication. Over the course of replication, about ten plus strands accumulate for each negative template strand. It has been shown that in order for Flaviviridae viruses to replicate successfully they must have complementary binding regions on both the 3’ and the 5’ ends of the genome which allow cyclization of the genome to occur.

Proteins:

Flaviviridae has three structural proteins as follows: C/V2 are the capsid proteins, M/V1 are the matrix proteins and E/V3 are the envelope proteins and glycoproteins. Flaviviridae encodes seven non-structural proteins whose functions are not entirely designated by include protease, helicase, replicase and virion maturation.

Viruses in the Flavi genera are transmitted by arthropods, mainly mosquitoes and ticks. Flaviviruses that are transmitted by arthropods are known as Group B Arboviruses. "Arboviruses" (viruses transmitted by arthropods) include Yellow Fever Virus, Dengue Fever Virus, and Japanese Encephalitis Virus (see list below for full inclusion). Viruses in the Hepaci genera, Hepatitis C and Hepatitis G, are transmitted parenterally (through blood) as well as sexually and vertically (from mother to child).

Prevention Vaccines exist for both Yellow Fever Virus and Japanese Encephalitis. Both vaccines are inactivated and have proved highly efficacious in labs and clinics. For more information about vaccines see Timeline. Otherwise the best ways to prevent infection with arboviruses are behavioral, such as using mosquito nets, bug repellent and protective clothing. With hepatitis viruses, behavioral preventative measures such as protected sex, refraining from injection drug use, and proper disposal of needles is suggested. Any blood or products that have come into contact with blood should be handled with utmost caution.

RNA Viruses- Picornaviridae and Orthomyxoviridae

Ahhhhhh CHOOOOOOOoooooo!!!


https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQuON4WQwZ5i6p5ocUlbZ6Vkmk-C6DKjhAQ25OAB0iYJ4AH45MN7G1lyj3B-iwUUBSfK3syID6KgRU6F5f5YDDIeSr0lpsYYDNf2I5L0ZJQEG5LDmVEzAkRtccdu-U9-Yu5WkV-mFTZZE/s320/sneeze1.jpg

Unique features of RNA Virus

1. Genome is infectious (+ RNA virus)
2. Unusual structural characteristics
   

Picornaviridae

Genome

1. One linear (+) RNA
2. Long untranslated region end of 5’end “clover leaf” structure
3. Single polyprotein
4. Both ends modified

Morphology

• Virions (naked)
• Nucleocapsid isometric
• Incomplete or empty capsids common

Picornaviridae- Rhinovirus

Orthmyxoviridae-Influenza

Genome of Influenza A&B

1. ss(-) RNA in 8 segments
2. 3 polymerase polypeptides with each segment
3. 5’ and 3’end of all segment highly conserved
   

Morphology

• Typically spherical
• Enveloped
• Pleomorphic (many forms)
• Spikes on envelope
• Groups of HA

What is the difference between Cold and Flu?
http://www.simcoemuskokahealth.org/images/Flu-cold-chart.gif

Antigenic Drift vs. Antigenic Shift

Antigenic drift is a mutation in the genetic code of surface antigens ( HA/NA)

Antigenic shift occurs when genes re-assort form different subtypes

Strain Naming Convention

Write according to this order:

1. Type

2. animal species (omitted if human)

3. place of isolation

4. number of isolate

5. year of first isolation

6. (H and N subtypes)

Enveloped DNA Viruses- Herpesviridae

Wait! Before you kiss, do you know that you could be at risk of contracting Herpes Simplex?

http://1heckofaguy.com/wp-content/photos/kiss%20lips%20350.jpg

Herpes virus Genome

http://stdgen.northwestern.edu/stdgen/bacteria/hhv2/herpes.diagram.jpg

All herpesvirus virions have four structural elements.

• Core - The core consists of a single linear molecule of dsDNA in the form of a torus.
• Capsid - Surrounding the core is an icosahedral capsid with a 100 nm diameter constructed of 162 capsomeres.
• Tegument - Between the capsid and envelope is an amorphous, sometimes asymmetrical, feature named the tegument. It consists of viral enzymes, some of which are needed to take control of the cell's chemical processes and subvert them to virion production, some of which defend against the host cell's immediate responses, and others for which the function is not yet understood.
• Envelope - The envelope is the outer layer of the virion and is composed of altered host membrane and a dozen unique viral glycoproteins. They appear in electron micrographs as short spikes embedded in the envelope.

Unique features of herpes virus

• Virus infects vertebrates.

• Following primary infection, virus remains latent until reactivation

Pathogenesis

1. Herpes Simplex Viruses

• HSV1 (cold sores) - oral cavity

• HSV2 (genital herpes) - genital

2. Varicella Zoster virus

• Varicella (chicken pox) - respiratory tract, pharyn
• Herpes Zoster (shingles)

Clinical Features- Herpes Simplex

http://i.ehow.com/images/GlobalPhoto/Articles/2041461/cold-sore-crop_Full.jpg

1. Cold sores- blister around mouth/eyes/gum for around 1 week
2. Genital herpes- blisters, burning sensation, discharge- 1-3 wks

Clinical Features- Varicella Zoster

http://www.childhoodhealth.com/images/varicella_large.jpg

1. Fever and lesion all over body.
2. Dangerous in pregnant women

Epidemiology and Control

Herpes simplex- avoid kissing, close proximity and risky sexual behaviours.

Varicella Zoster- vaccine available for VZV, avoid infected people.

Enveloped DNA Virus- Hepadnaviridae

LOOK HERE!

picture courtesy of http:// www.saddleback.edu/alfa/N172/images/jaundic.jpg

The picture above shows a symptom of acute hepatitis B- jaundice.

WHAT IS HEPADNAVIRIDAE?

Hepadnaviridae (Hepa = liver; dna = deoxyribonucleic acid)

As their names imply, all of the known hepadnaviruses are hepatotropic, infecting liver cells, and all can cause hepatitis in their known host. Hepatitis is the a syndrome characterized by inflammation of the liver.

Unique Features Of The Genome

1. Partial dsDNA

2. Endogenous DNA-dependent DNA polymerase

3. Use of overlapping reading frame

4. RNA intermediate

1 virus that is pathogenic to man: Hepatitis B virus(HBV)!

picture courtesy of http://www.hivandhepatitis.com/2006icr/ddw/images/cirrhosis-liver.jpg

Pathogenesis

Acute or chronic liver infection is dependent on age of infection. The younger a person is when she becomes infected with HBV, the more likely she is to be asymptomatic and become a chronic carrier of the disease. Babies born to infected mothers are at very high risk of to becoming carriers and developing liver pathology. About 90% of adults who acquire HBV recover from it completely and become immune to the virus. The other 10% of cases are the people who become chronic carriers.

Clinical features- Acute and Chronic

Clinical Features (Acute)

• loss of appetite, nausea, vomiting, fever, abdominal pain and jaundice
  
• about 90%-95% adults recover without sequelae
  
• 5%-10% become chronically infected.
  

Clinical Features (Chronic)

• Carrier state-have no symptoms and no abnormalities on lab testing.
  
• Some will develop cirrhosis
  

Lab Diagnosis

Hepatitis surface antigen (HBsAg) first appears in the blood during the incubation period, while the virus is actively 'replicating' in liver cells.

In acute infection, the HBsAg usually disappears within 3 months of onset. The Hepatitis envelope antigen (HBeAg) and HBV DNA can also be detected in blood while the virus is actively replicating in the liver.

Diagnosis of HBV infection is generally made on the basis of serology.

Antibody to HBcAg (anti-HBc) rises first. As a generalisation, the detection of IgM antibody specific to the hepatitis B core is the primary indicator of acute infection. It usually appears at or just before the onset of symptoms and remains detectable for at least 6 months. Subsequently,IgG antibodies against core are produced.

As acute infection resolves, IgG antibodies against core antigen persist and IgM and HBsAG becomes undetectable.

So, most people who have had acute infection continue to have IgG antibodies against core antigen for life. The diagnosis and prognosis of hepatitis B is confirmed and assessed by liver biopsy.

Epidemiology

Mode of transmission: blood and sexual contact

Control

- Avoid risky sexual behaviours and sharing of needles.

In this lecture we were taught about the Heptitis B virus and reminded of the dangers of risky sexual contacts. No! I don't want to risk having liver cancer. What about you?

Classification of Viruses

For our 1^st lecture of the semester we learnt about the Classification of Viruses! It was quite interesting to gain more insights of how the World of Virology works. But we guess it will mean more memory work for the coming exams!

So we classified what we learnt today into 3 groups:

A. Virus taxonomy

B. Lwoff’s Classification

C. Baltimore's Classification

Taxonomy and Classification is a mean to classify and identify living things.

There are 8 main taxonomic ranks: domain, kingdom, phylum, class, order, family, genus, species, and it gets more specific as it goes down the row.

The lecturer told us an easy and fun way to memorise this table!

Keep Plates Clean Or Family Gets Sick

Picture courtesy of flickr.com/photos/

Classification of Viruses

Morphology: Viruses are grouped on the basis of size and shape, chemical composition and structure of the genome, and mode of replication.

Chemical Composition and Mode of Replication: The genome of a virus may consist of DNA or RNA, which may be single stranded(ss) or double stranded(ds), linear or circular.

Hmm.. So how did the classification of viruses come about?

A. Virus Taxonomy-ICTV

International Committee on Taxonomy of Viruses

Taxonomy lies at the uneasy interface between biology and logic. The processing of information follows somewhat different rules in these two systems and the role of taxonomy is to reconcile them as tidily as possible. To thisend, the International Union of MicrobiologicalSocieties (IUMS) charged the International Committee onTaxonomy of Viruses (ICTV) with the task of developing,refining, and maintaining a universal virus taxonomy. The goal of this undertaking is tocategorize the multitude of known viruses into a single classification scheme that reflects their evolutionaryrelationships.

B. Lwoff's classification

In 1962 Lwoff, R. W. Horne, and P. Tournier advanced a comprehensive scheme for the classification of all viruses consisting of phylum - class - order - family - subfamily - genus -species - strain/type. Four main characteristics are used:

1. Nature of the nucleic acid:RNA or DNA

2. Symmetry of the capsid

3. Presence or absence of an envelope

4. Dimensions of the virion and capsid

C. Baltimore's Classification

The Baltimore classification is based on genetic contents and replication strategies of viruses.

According to Baltimore classification, viruses are divided into the following 7 classes:

photo coutesy of http://www.web-books.com

1.dsDNA viruses

2.ssDNA viruses

3.dsRNA viruses

4.(+)-sense ssRNA viruses

5.(-)-sense ssRNA viruses

6.RNA reverse transcribing viruses

7.DNA reverse transcribing viruses

WARM WELCOME TO THE WORLD OF VIROLOGY!!

YES!! YOU!! THAT'S RIGHT, YOU!! THE ONE WHO IS READING OUR BLOG NOW!!

We would like to say a big.....

to you!!!

ACCESS GRANTED!!

You have just entered to The World Of Virology!!

You must be wondering why we set up this blog for??

We would like to share our knowledge with everyone about viruses on what we have learnt during our lectures in school!!

WE LOVE SHARING!!!

However, note to take:

What we have learnt are the basics of virology (:

Want to know more about HIV, AIDS??

Or are curious about what is the cause of mad cow disease....?

STAY TUNE TO VIRUS RADIO STATION!!