Doctors detected the first positive case of dengue fever of the season on Wednesday and warned of possible outbreak of the disease in the capital city. A Frontier Constabulary constable was the first to contract the disease from the barracks where he had been staying. He was later admitted to Polyclinic Hospital with high fever, where he is still being treated. "We are sure that he contracted the disease from there because he had not been out of the city for the past 30 days,' doctor treating him at the hospital said. Afterwards three of his other colleagues staying in the same barracks also acquired the disease. Their blood samples are being tested at National Institute of Health for confirmation. None of the reported cases are haemorrhagic. The barracks have been sprayed with insecticide to prevent further transmission of disease to other personnel residing there. Worried doctors said epidemiologically one positive case meant several others were in the pipeline. Islamabad has been regularly getting dengue fever cases over the past few years. The cases normally started coming in September and their figures peaked by November, but this year early monsoon has brought in early cases. "The rains have produced conditions conducive for the disease,' a doctor explained. Dengue fever is a disease caused by a family of viruses that are transmitted by mosquitoes Aedes aegypti. It is an acute illness with symptoms ranging from headache, fever, exhaustion, severe joint to muscle pain, swollen glands (lymphadenopathy), and rash. The deadly dengue virus was not a major health issue in the country a few years back. The first confirmed outbreak of dengue fever was reported in Pakistan in 1994. Since then only sporadic cases were reported till 2006, when a major outbreak was witnessed with over 1000 confirmed cases mostly from Sindh and Punjab. Prospects for reversing the recent trend of increased epidemic activity and geographic expansion of dengue fever are not promising, the health experts warn. With no new mosquito control technology available, public health authorities have emphasized disease prevention and mosquito control through community efforts to reduce larvae breeding sources. Aedes aegypti mosquito bites during the day, lives indoors in domestic settings and breeds in both clean and polluted water. While adult mosquito is killed in 38 degrees centigrade, the eggs can withstand desiccation and can hatch even the next year when conditions are conducive. Dengue fever, experts believe, was not a health issue alone and was also related to our environment. They contend that the role of municipal administration is all the more important since fumigation, fogging and removal of solid waste from the cities is their job but seldom performed satisfactorily. The World Health Organisation (WHO) endorses this view that proper vector control by involving municipal administrations and social mobilisation and education of the people about the disease can effectively contribute towards controlling the disease.