Infectious diseases, including dengue, respiratory illnesses and water-borne diseases like shigellosis are set to increase in the State in the coming weeks. Thiruvananthapuram, which has always had the dubious distinction as the State’s dengue capital, would likely see cases spiralling, it was pointed out at a review meeting of various district health administrations and district collectors, chaired by the Health Minister K. Muraleedharan, here on Wednesday.