Thiruvananthapuram, June 24 (ANI): With the onset of Monsoon there is a gradual rise in fever cases with as many as over 1000 cases, reported by the civic health department, seeking treatment in hospitals in southern India this month alone. The hospital in Thiruvananthapuram city of Kerala is crowded with patients complaining illnesses pertaining to monsoon. The monsoon may have come in as a respite for people from strong heat waves in Kerala, but it is proving negative as communicable diseases are on a high, claims the state health department. Patients have mostly come to hospitals with cough, cold and fever. While most are normal viral fevers, doctors are advising caution and adequate rest to ensure that things do not get out of hand. An alert for Leptospirosis, also known as field fever, has been issued as a precautionary measure, since monsoon struck the coastal state.