I was just wondering how do we know the cold is virus related. The symptoms seem all similar such as sore throat, chills, headache, running nose and fever.

The virus that causes the flu or a cold or viral meningitis are independent entities and although some viruses give some symptoms, others may give those same symptoms and then others from its own particular make up. Flu viruses are potent and can cause death, the cold virus causes less severe symptoms. Last year there was, if you remember the world wide concern over swine flu.

Although essentially it is usually described by sufferers as an uncomplicated influenza-like illness, symptoms of fever, cough or sore throat being reported in most cases, mild respiratory illness, nasal congestion, rhinorrhea (runny nose) without fever and occasional severe disease also has been reported. Other symptoms reported with swine influenza A virus infection include vomiting, diarrhoea, myalgia (muscular aches) headache, chills, fatigue, and dyspnoea (shortness of breath) Some reports of conjunctivitis although rare, have been reported. Severe disease (pneumonia, respiratory failure) and fatal outcomes have been reported with swine influenza A virus infection.

The threat from swine flu came in its potential for exacerbation of underlying chronic medical conditions or invasive bacterial infection with swine influenza A virus infection which is usually the main concern and has been responsible for the deaths associated with this virus.

The following are conditions considered to make you vulnerable to the worse effects of swine flu:

chronic (long-term) lung disease, including people who have had drug treatment for their asthma within the past three years,
chronic heart disease,
chronic kidney disease,
chronic liver disease,
chronic neurological disease (neurological disorders include motor neurone disease, Parkinson's disease and multiple sclerosis),
suppressed immune systems (whether caused by disease or treatment),
diabetes,
pregnant women,
people aged 65 or older, and
young children under five

Indeed there are many questions that surround swine flu, and other viral infections, such as is it possible to become infected twice?

In fact it is because the virus can change or mutate. When you catch a virus, under normal circumstances, and in an otherwise healthy person, your body will produce antibodies against the virus and should you come into contact with that virus again, in the same form, your body will have the capability to fight it off. However if the virus does mutate, your immune system will have more trouble recognising it in its mutated form and you may become ill again. It is possible that having had the virus in one form previously may help your body protect you to some extent from the mutation.

Hi,
Old's tend to produce runny nose, congestion, sore throat. Influenza is more pronounced in that it infects the lungs, the joints and causes pneumonia, respiratory failure and even death. It tends to infect the intestinal tract more in kids, with diarrhea and vomiting. Because of the relative immaturity of the gut, they may absorb more virus and that wreaks more havoc on the intestines. Flu causes epidemics and pandemics with the potential for mortality, whereas the common cold is a nuisance for us.

Great reply Karl. I once remember someone saying the say that you can tell if you have a bad cold or flu is to imagine that in front of you on the floor is a $100 bill. If you could not be bothered to lean over and pick it up, then you have flu!

The effects although they act on the same systems of the body, differ in severity, as you pointed out Karl. Real flu can be a killer so don't be afraid to ask for help if you feel you need it!

Thanks paddy for that eg. i feel that when it is flu then the symptoms are much different then the other cough cold condition, we can see a pattern in the viral infection, some times we have virus attack and we notice that the fever stays for a day, and then without taking medicines it goes, and then on next day we feel fever. It is all about the different stages of attack of viruses, like in malaria we observe different pattern of attack, female anopheles complete its asexual as well as sexual life cycle in the peritrophic membrane of human liver, and thus there are different stages are observed in malaria.