Although the promise of spring is in the air, we have not seen the last of patients complaining of colds and flu. But what is what and when is it a cold and when is it flu? Both conditions are caused by viruses and therefore neither can be treated with antibiotics but the symptoms differ substantially. The common cold is centred in the nose. The three most frequent symptoms of a cold are nasal stuffiness, sneezing, and runny nose. Patients also complain of a throat irritation but do not present with a red throat. Adults and older children with colds generally have minimal or no fever. Depending on which virus is the culprit, the virus might also produce a headache, cough, postnasal drip, burning eyes, muscle aches, or a decreased appetite. Within one to three days, the nasal secretions usually become thicker and perhaps yellow or green. With the flu, the patient feels sick all over. Classically, the flu begins abruptly, with a fever, a flushed face, body aches, and marked lack of energy. Some people have other systemic symptoms such as dizziness or vomiting. Somewhere between day 2 and day 4 of the illness, the whole body symptoms begin to subside, and respiratory symptoms begin to increase. The virus can settle anywhere in the respiratory tract, producing symptoms of a cold, croup, sore throat, bronchiolitis, ear infection, and/or pneumonia. The most prominent of the respiratory symptoms is usually a dry, hacking cough. Most people also develop a sore (red) throat and a headache. Nasal discharge and sneezing are not uncommon. According to Prof. Elvis Irusen, clinical director of the University of Stellenbosch ’s lung unit at the Tygerberg Hospital , the influenza season lasts from April to August. Two strains of  the flu virus have been identified by WHO for the 2008 southern hemisphere influenza season: A/Solomon Islands/3/2006 (H1N1) – like virus A/Brisbane/10/2007 (H3N2) – like virus B/Florida/4/2006) – like virus or B/Brisbane/3/2007 The strain of virus predicted to be the most potent in a year is determined by a group of scientists who work for WHO and monitor the influenza virus all over the world. They then inform the pharmaceutical companies, who in turn prepare the influenza vaccine. Prof. Irusen single out a number of vulnerable groups such as people older that 65 years, children, people who share working and living space, those with chronic illnesses and people with suppressed immune systems such as people with HIV/Aids and TB. He also warns that persons who exercise a lot are also very susceptible to the flu virus as a result of the micro tears to the muscles. This leaves them predisposed to infections and puts the immune system under strain....