Antiviral medicines

Much like antibiotics, a particular set of antiviral is used to treat a particular set of virus. Viruses cannot reproduce on their own; they invade the human cell, attach themselves to it and replicate themselves. The drugs act by interfering with the virus and stopping it from entering the cell and replicating itself. Few antiviral drugs block the virus's entry into the cell itself, yet a few prevent the virus from replicating itself. A few anti-viral drugs stimulate the immune system so that the body can fight the viruses on its own. Antiviral drugs are used to cure conditions like common cold, flu, measles, mumps, chicken pox etc. Common antiviral drugs include Arbidol and Oseltamivir to treat influenza and Ritonavir - used to treat HIV infection.

CJD

This is a rare degenerative disease, a fatal brain disorder. One in every million worldwide is affected by Creutzfeldt Jakob disease which occurs about age 60, and about 90 percent of patients die within a year. Since first described in 1920, less than 1 percent of cases have acquired CJD.

Signs and symptoms

During the early stages of the disease failing memory, behavioral changes, lack of coordination and visual disturbances are exhibited. Impaired memory, judgment and thinking and insomnia, depression or unusual sensations are other symptoms. CJD may also cause fever or other flu-like symptoms. As the illness progresses, mental deterioration becomes severe. Involuntary movements, blindness and weakness of extremities are other symptoms.

Rapidly the disease progresses into dementia. Patients eventually lose the ability to move and speak and then enter a coma. Pneumonia and other infections may occur in these individuals and can lead to death. Some symptoms of CJD can be similar to Alzheimers or Huntington disease. CJD causes unique changes in brain tissue which can be seen at autopsy and the deterioration is more rapid than Alzheimer's disease or other types of dementia.

Major categories of CJD

Sporadic CJD: Here the disease appears even though the person may not exhibit any known risk factors. This is by far the most common type of CJD and 85 percent cases come under this category.

Variant CJD is caused by consuming meat from a cow that had Bovine Spongiform Encephalopathy (BSE) or mad cow disease, a prion disease similar to CJD. Strict controls have proved very effective since its discovery in 1996.

In hereditary CJD, the person has a family history of the disease and tests positive for a genetic mutation associated with CJD. About 5 to 10 percent of cases in the US are hereditary and the symptoms usually develop in early 50s.

In latrogenic CJD, the infection spreads from someone through medical or surgical treatment. A common instance of this is spread of CJD from someone with growth hormone treatment using human pituitary growth hormones extracted from deceased individuals who might have had CJD infection.
CJD is not contagious through casual contact with a CJD patient.

Causes

Researchers believe that an unusual slow virus or any other organism causes CJD. But they have never been able to isolate a virus or any organism in people with the disease. As the agent causing CJD has several characteristics other than known organisms such as bacteria and virus, it is difficult to destroy as it does not contain any genetic information in the form of nucleic acids. For example, prions are not destroyed by the extremes of heat and radiation used to kill bacteria and viruses, and antibiotics or antiviral medicines have no effect on them. It also incubates for a long period of time before the symptoms appear, as long as even 50 years. The leading scientific theory maintains that CJD is caused by a type of protein called as a prion. Also 5 to 10 percent of CJD cases are inherited. These cases arise from a mutation, or change in the gene that controls formation of the normal prion protein.

Diagnosis of CJD

There is no single diagnostic test for CJD. First, all treatable forms of dementia are ruled out. A neurological examination is performed and consultation with other physicians is sought. Spinal tap, electroencephalogram, CT and MRI and brain scans can reveal characteristic patterns of brain degeneration that can help diagnose CJD.

For a confirmed diagnosis of CJD, brain autopsy is the only way. A neurosurgeon removes a small piece of tissue from the patient's brain and it is examined by a neuropathologist. The procedure may be dangerous as it does not always obtain tissue from the affected part of the brain. Brain biopsy is discouraged unless it is needed to rule out a treatable disorder. In autopsy, the whole brain is examined after death. Special surgical and disinfection procedures can minimize the risk. Scientists are working to develop laboratory tests for CJD.

As such there is no treatment or cure to control CJD. Studies are on to try a variety of drugs but none of the treatments have shown consistent benefits in humans. Treatment aims at alleviating symptoms and making the patient as comfortable as possible. Opiate drugs can help relieve pain. During later stages of the disease, changing person's position frequently can keep them comfortable and help prevent bed sores. A catheter is used to drain urine if bladder control is lost. Intravenous fluids and artificial feeding are also used.

Avoid spreading CJD

To reduce the very low risk of CJD transmission from one person to another, it is better not to donate blood, tissues or organs if suspected or confirmed with CJD because of family history of the disease. As normal sterilization procedures such as cooking, washing and boiling do not destroy prions, the following precautions are suggested by the World Health Organization while dealing with patients contacted with CJD.

• Cuts and abrasions should be covered with waterproof dressings.
  
• Surgical gloves should be worn when handling a patient's tissues and fluids or dressing up patient's wounds.
  
• Avoid cutting or sticking with instruments contaminated by patient's blood or tissues.
  
• Use disposable bedclothes for contact with patient.
  
• Use face protection if there is risk of splashing contaminated material such as blood or cerebrospinal fluid.
  
• Soak instruments that have come in contact with patient in undiluted chlorine bleach for an hour or more and then autoclave to sterilize them in distilled water for at least one hour at 132-134 C.