The ONLY human disease caused by VIRIODS!!

Hepatitis A?? B?? C?? THE CORRECT ANSWER SHOULD BE HEPATITIS D!!! This disease was previously attributed to a defective virus called the delta agent. However, it now is known that the delta agent is a viroid enclosed in a hepatitis B virus capsid. For hepatitis D to take place, there must be simultaneous infection of a cell with both the hepatitis B virus and the hepatitis D viroid. There is extensive sequence complementarity between the hepatitis D viroid RNA and human liver cell 7S RNA. The hepatitis D viroid causes liver cell death via sequestering this 7S RNA and or cleaving it. Hepatitis D viroid can only enter a human liver cell if it is enclosed in a capsid that contains a binding protein. It obtains this from the hepatitis B virus. The delta agent then enters the blood stream and can be transmitted through blood or serum transfusions.

Do APPLE get DISEASES??

The green apple in the picture taken above seemed to have suffered from some kind of "skin allergy"!! It looks just like those itchy rashes on our own skin and the colour of those spots is somehow simliar. However, it is not "skin allergy"!! This is a kind of apple disease, Apple Scar Skin. It is one of the most destructive diseases affecting apple which is caused by Apple Scar Skin viroid (ASSVd). Fruit dappling appeared on several cultivars in Korea and has been distributed to major cultivated areas since 2001. ASSVd was identified from infected fruits by using nucleic acid sequence-based amplification with electrochemiluminescence (NASBA-ECL). Affected fruit bears small circular spots near the calyx end of the fruit. As the fruit matures, the spots enlarge and the spots increasingly contrast with the darkening background color of the fruit.

The mastermind of the apple disease mentioned earlier is VIRIOD!!

Well well well what are viriods?? Have any idea?

They are the smallest known agents of infectious disease. Whereas conventional viruses are made up of nucleic acid encapsulated in protein (capsid), viriods are uniquely characterized by the absence of a capsid. In spite of their small size, viroid ribonucleic acids (RNAs) can replicate and produce characteristic disease syndromes when introduced into cells.

Potatoes that suffered from PSTVd

Another example of plant disease caused by Viriods is Potato Spindle Tuber Viriod (PSTVd). Potato is the main host of this disease! Infected tubers are small, elongated, characteristically spindle or dumb-bell shaped, often with prominent bud scales evenly distributed over the surface. Futhermore, growth cracks may also occur.

Recommendation of the day!!

Fatal Protein: The Story of CJD, BSE and Other Prion Diseases By Rosalind Ridley, Harry Baker

We would like to recommend this interesting book specially for those who are interested in knowing more about the history of scrapie in sheep, the spread of kuru through cannibalism in Papua New Guinea, and the BSE epidemic in Britain - "mad cow disease" - which claimed over 170,000 cattle and threatened the rest of Europe. The authors presented a detailed description of the human prion diseases, and also examined the evidence that the new variant of the Creutzfeld-Jakob disease results from eating infected by BSE. At the heart of this book lies a discussion of the still controversial idea that the infectious agent in prion diseases is a normal brain protein which takes on abnormal, mutant shape, the so-called "prion theory".

Symptoms of CJD, Mad Cow and Scrapie

Overview of transmission of PRIONS!!

SPONGE-LIKE Human Brain!!!

MRI scan of a CJD brain, showing its spongy appearance.

Look at the picture carefully!!

Are you able to spot those tiny winy holes in the brain??

Classic Creutzfeldt-Jakob disease (CJD) is a human prion disease and also a neurodegenerative disorder with characteristic clinical and diagnostic features. This disease is rapidly progressive and always deadly. Most importantly, we would like to state out a point that classic CJD is not related to "mad cow" disease. Infection with this disease leads to death usually within 1 year of onset of illness.

*Important Note: Classic CJD also is distinct from "variant CJD", another prion disease that is related to BSE.


Four types of CJD




Cause of CDJ
- a specific protein called a prion, which lacks nucleic acids, resists proteolytic digestion, and spontaneously aggregates in the brain.

The tissue slide above displays sponge-like lesions in the brain tissue of a classic CJD patient. This lesion is typical of many prion diseases. Most cases are sporadic; 5% to 15% are familial, with an autosomal dominant pattern of inheritance.

In the present, there is only treatment for relieving symptoms. Current clinical trials are testing promising antiviral drugs such as amantadine, which has proven helpful in treating Parkinson's disease. Some patients taking these antivirals have shown brief periods of improvement, with no harmful side effects. However, no treatment has been discovered that stops CJD completely. It is invariably fatal, often within a year of the onset of symptoms.

The SHEEPS’ and GOATS’ KILLER!!

This disease was known since the 18th century, but till the 60s that scientists began to suspect that it wasn’t a typical disease, self-replicating outside of the usual means of nucleic acids. This fatal and infectious disease is none other than scrapie, which cause horrible symptoms on animals it infect before death. If you are curious about how the name of scrapie come about, continue to read on….. The name of the disease came from the disturbing behaviour of infected sheep, to scrape off their fleece against rocks. It is quite saddening if you try to visualise yourself in the picture of this happening, witnessing the whole entire process.

Scrapie causes a degeneration of the central nervous system which eventually results in a variety of behavioral, locomotive changes and death. Sad to say that up till today, there is still neither cure nor treatment. In other words, the cruelty of this killing will continue to happen on any innocent sheep or goat.

Do you have any idea of what causes scrapie??

An agent that is smaller than a virus causes scrapie. It is either a protein called a prion or another substance closely associated with the prion protein. Scientists still have many to learning about the scrapie agent and exactly how it works. It is known that the scrapie agent is extremely resistant to heat as well to normal sterilization processes. Besides that, it does not evoke any detectable immune response or inflammatory reactions in host animals. The incubation period is usually two to five years. Ultimately, the scrapie agent attacks the brain, leaving holes in it much like swiss cheese or a sponge, hence the name spongiform encephalopathy.

Have you heard of MAD COW Disease??

MOO!! I bet almost everyone does! Not because it is COMMON, but because of its outbreak in countries such as Europe, Britain, U.S.A, Canada and Japan. In 1986, the first occurrence of mad cow disease took placed in England. The scientific name for Mad Cow Disease is bovine spongiform encephalopathy (BSE), a progressive neurological disorder of cattle which can be transmitted to other species, including human beings. The disease is so named as it causes the brain of the victim to degenerate into a sponge-like consistency.
The actual cause of BSE is still unknown, however, it is generally accepted by the scientific community that the likely cause is infectious forms of a type of protein, prions, normally found in animals cause BSE. In cattle with BSE, these abnormal prions initially occur in the small intestines and tonsils, after which are found in central nervous tissues, such as the brain and spinal cord as well as other tissues of infected animals experiencing later stages of the disease.