With the season about to change, the weather is hot and sticky. High humidity levels can play havoc with your immunity, warn doctors. Viral fever cases are on the rise and will not subside till weather conditions stabilise, they say.Fever-ish pitchViral fever refers to a broad spectrum of conditions, mostly associated with viral infections, that lead to a rise in body temperature. Though they require only symptomatic treatment, some are highly contagious. Generally not dangerous, they can at times prove fatal. “The body does not take well to the constantly changing weather. It affects immunity,” says Dr Anoop Misra, HoD, diabetes and metabolism, at Fortis Hospital in Delhi.The symptomsThough viral infections target specific organs, the symptoms are more or less the same. Here’s a checklist: Body ache, mild to high fever, running nose, cough, shivers, skin rashes, irritability, inflammation of the throat, redness of the eyes, pain in the muscles and joints, fatigue and swollen lymph glands in the neck.Common causesInfections are inevitable if you are not careful about what you eat. “Most viral infections are caused by the intake of contaminated water or food, or by direct contact. The infection spreads locally and then enters the blood stream or lymph channels,” explains Dr Misra. Once a virus enters the body, there is an incubation period during which it multiplies enough to cause an infection.Worry someAre viral infections serious? “It is usually selflimited, though the fatigue and cough may persist for weeks. But it’s dangerous if the illness is followed by bacterial infection. You might then need medication or even hospitalisation,” says Dr Misra. Viral infections can lead to pneumonia, vomiting, diarrhoea and jaundice.Risky businessThosewithkidney,heartandlungproblems, shouldtakecare.People ailingfromasthma,obstructiveairwaydiseaseandhydrosisofthelungs arepronetoviralinfections.Pregnantwomen, childrenandtheelderlyarealso vulnerable.The prescriptionThere aren’t any substantial preventive measures. Avoid crowded places. Also, if someone in your family has contracted some infection, chances are you will get it too. Ensure adequate fluid intake, and take rest if symptoms appear.