Dengue fever outbreak that began in Pakistan in July has become an epidemic, with at least 28 people dead and over 5,000 people infected, Pakistan media said on Saturday. Provincial authorities have closed schools in Punjab, the country\'s worst-hit province, for 10 days to prevent the further spread of fever. The dengue virus causes an infectious tropical disease known as dengue fever, which is characterized by headaches, severe joint pain, and a rash. In some cases, far more life-threatening hemorrhagic fever or shock syndrome can develop. Pakistan is trying to contain the outbreak of the mosquito-borne illness, but medical supplies in the region are running out. A team of experts from Sri Lanka is due to arrive in Pakistan in the coming days to help the government deal with the disease. Punjab is Pakistan\'s most-populous province, with 56 percent of the country\'s population of some 173 million living there. Pakistan is already coping with flooding that has killed more than 225 people in recent weeks. Experts say poor hygiene is responsible for the spread of the disease, but heavy monsoon rains are also providing a breeding ground for mosquitoes, carriers of dengue fever.