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Dear ViroMag Viewers, Peace!

I think I shall ‘recruit’ more viewers from outside the field, and I intend to do so by teaching the public ‘BASIC VIROLOGY’, so that they can catch up with what we post here.

Here is my first attempt to do so, here is a nice animation summarizing basic processes concerning life cycle of a virus, spend some time exploring this animation and I’d be glad to answer questions that arise in your mind

And for those who don’t know what a virus is! (which is a prerequisite before you see this animation!)

“Viruses are distinct biological entities with the following properties:

1. A virus is an infectious, obligate intracellular parasite.

2. The genetic material of a virus is either DNA or RNA.

3. The genetic material of a virus enters a host cell and directs the production of the building blocks of new virus particles (called virions).

4. New virions are made in the host cell by assembly of these building blocks.5. The new virions produced in a host cell then transport the viral genetic material to another host cell or organism to carry out another round of infection.”

Here is the animation (waiting for questions!)

Peace be upon YoU, Here is a Nice Video about Flu, enjoy

Vodpod videos no longer available.

 

Immunodiffusion

Peace be upon you, yesterday in our weekly Medical Immunology section we were talking about ‘Immunodiffusion‘ we first talked about what is meant by immunoprecipitation? (the principle behind immunodiffusion techniques) which simply is ‘a technique in which an antigen is precipitated from solution by using an antibody’, we discussed a little the ‘point of equivalence’ where maximum precipitation takes place, when optimal proportions of antigens and antibodies are met ‘to cross link and form a lattice

then we talked about ‘Gel Immunodiffusion’ where reactants (antigen and antibodies) diffuse through a substance such as agar, and lines of precipitation are observed in Gel!

Immunodiffusion may be carried out as either ‘single radial immunodiffusion’ or ‘double immunodiffusion’ reactions, in single immunodiffusion reactions, only one reactant diffuse through the gel, and the other is ’embedded’ in the gel!, where results appear as a ring of precipitation around the well containing the diffusing reactant.

Second ‘double immunodiffusion’ which is also called ‘Ouchterlony Double Immunodiffusion‘ where both reactants (antigen and antibodies) diffuse in opposite directions towards each other forming an arc (not a ring!)

Immunodiffusion reactions can be done in Plates

like this one,

and it is obvious (as shown above) that they can be also made on slides !!!

I left them with a question to comment on the following figures, I’ll leave the answer to them, and we can discuss the answer in another post

Dear 4th year Microbiology/Special students, Peace be Upon You, here is the Animation I was talking about Last Section, watch and feel free to Leave your comments and questions

Vodpod videos no longer available.

Imagine being eaten alive — from the inside out! That is what happens to any caterpillar unlucky enough to become the nest for an egg laid by a caterpillar wasp.

Remarkably, some plants have evolved a way to use caterpillar wasps to defend them from attack by hungry wrigglers. Here’s how it works: When a caterpillar bites certain plants, it leaves behind a drop of saliva that causes the plant to release chemicals of its own, called terpenoids. Like a silent scream or a chemical distress signal, the terpenoids warn the wasps that caterpillars are nearby. The wasps then flock to the plant, laying eggs on the vulnerable caterpillars. Several days later, the tiny wasp larva hatches anCaterpillar waspd begins eating thecaterpillar alive!!!.

Some wasps get a little help from a special virus in protecting their newly laid eggs. they inject the virus into the caterpillar along with the egg. the virus prevents the caterpillar’s immune system from attacking the egg. In return, the wasp supports the virus by providing a host. The only loser in the arrangement is the hapless caterpillar.

Immune Evasion

Dear Viewers of ViroMag, Peace be upon You

A few days ago I had a conversation with a student which finally led us to talk about ‘Immune Evasion strategies’ adopted by viruses, she was asking about ‘How viruses could establish an infection, though presence of all these cellular defences?’, actually her question could be more broadly asked as ‘How viruses succeed in infecting our bodies, complete their life cycle, and cause disease in the presence of Immune System in our bodies?!’

We talked generally about the issue, but I think the answer lies in that viruses were created with capabilities which are strengthened by continuous evolution to ‘evade immune responses’ through many mechanisms, and here is ‘An Introduction to the Immune Evasion Strategies‘;

As invaders, parasites, and pathogens initiate the relationship with host species to support their own chances for survival, proliferation, and subsequent dissemination. A stable interaction, from their perspective, consists of a high prevalence rate among the host population and lifelong persistence with minimal symptoms of disease. Achieving such goals would guarantee sufficient time for reproduction and passage to new hosts.

The host immune system, however, mobilizes its molecular arsenal to prevent multiplication and eliminate the infectious agent.

Pathogens, in response, have evolved various strategies to deal with the threat of the host immune system.

What are the basic types of evasion strategies?

  • Passive Mechanisms:

  1. Viruses, such as herpes simplex virus, enter a state of latency in which viral protein production is drastically down-regulated.

  2. Other microbes reside in so-called privileged tissues (salivary glands, neurons) in which factors of the immune response are not active.

  3. Some pathogens exhibit antigenic variation to prevent the immune system from preparing for re-infection

  • Active Mechanisms:

  1. Host-specific active strategies often involve the production of pathogenic immune-modulatory proteins which alter normal host protein function and general immune function

  • Aggressive Mechanisms:

  1. Microbes, like HIV and the measles virus, infect cells essential for immune function (T and B lymphocytes, monocytes), thereby causing immunosuppression”

Dear Viewers, Peace be upon you all, Here is the answer to the question that I posted few days ago “Can Saliva Transmit Hepatitis C?“, but first, for those who have no information about Hepatitis C Virus, they can go back and read first a previous post here in this blog about Hepatitis C in Egypt, “HCV in Egypt – A HOT SPOT !

Now back to our question “Can Saliva Transmit Hepatitis C?“:

Here are some information for you;

  • The concentration of Hepatitis C virus in a drop of infected blood is exponentially higher than the concentration of HIV in a drop of infected blood (this explains why it is important to avoid anything that could possibly be tainted with any amount of blood)

  • Unlike many other viruses (like HIV), any potential source of blood to blood contact seems capable of carrying the Hepatitis C virus. This is true, even if the source is indirect, such as a used razor, making HCV far more transmissible than most other blood borne viruses

  • While not normally found in urine, semen, vaginal/cervical fluids, feces or saliva, injury or illness may cause some of these substances to be contaminated with blood

  • In nearly half the cases of Hepatitis C, the infected individuals cannot identify the source for their infection

Here are results from studies concerning the issue:

1. As published in the September 2006 issue of Journal of Viral Hepatitis, German researchers investigated the transmission of Hepatitis C via a toothbrush. A team from the University of Regensburg examined 30 patients with Hepatitis C to see whether they had contaminated their toothbrushes with the virus. They collected saliva samples from infected patients both before and after tooth brushing. Figures showed that 30 percent of infected patients tested positive for traces of the virus in their saliva before brushing their teeth, while 38 percent tested positive in their saliva after brushing. Additionally, about 40 percent of the water used to rinse the infected toothbrushes tested positive for the virus. This information confirms the caution against toothbrush sharing, and also sounds a possible Hepatitis C transitory alarm.

2. In September of 2003, evidence that saliva contains the Hepatitis C virus was disclosed at the Interscience Conference on Antimicrobial Agents and Chemotherapy. Scientists from the University of Washington in Seattle concluded that while saliva may be infectious, the strongest predictor of viral presence in the saliva is serum viral load. Researchers found that Hepatitis C was not found in saliva if the person’s viral load was under one million. Additionally, any risk of acquiring infection through salivary contact existed only in the presence of gum disease. Investigators attribute this risk to microscopic amounts of blood in the saliva and visually undetectable open mouth wounds present in gum disease.

All possibilities must be considered in trying to determine how unknown sources of Hepatitis C infection took place. Although Hepatitis C has been detected in saliva, the necessary conditions render it unlikey—but not impossible—to be transmitted by kissing or through the sharing of a toothbrush.

Before anybody panics about these potential risks, remember that there are conditions accompanying these possible modes of transmission:

  1. The person with the virus must have a viral load over one million.

  2. Both parties involved have gum disease.

While experts view the risk of transmitting this disease through saliva as extremely low, it is recommended to maintain good oral hygiene, and toothbrushes be used solely by their owners

NOTE of Importance;

Knowing that risk of transmitting the disease through saliva as extremely low, shouldn’t stop you from calling a physician, it will cost you nothing, just a phone call, or a regular visit, discuss the issue with him, he shall give you more specialized advice about how to avoid more risks in the future;

It is not my intention in this blog to give – by any means – any MEDICAL ADVICE at all!, seek a physician whenever you should do

Thanks for reading my blog, feel free to send me your comments