New Dehli, India ? Outbreaks of mosquito-borne diseases in northern and southern India left ordinarily overburdened hospitals and clinics swamped with patients Wednesday, and officials reported at least 87 deaths.

The surging cases of dengue in the north and chikungunya in the south come as the annual monsoon tapers off across much of the subcontinent, leaving behind countless small pools and puddles of dirty, stagnant water where infectious mosquitoes breed.

While a dengue outbreak is an annual post-monsoon occurrence in parts of northern India, this year’s has been particularly widespread, with more than 400 cases compared with last year’s 217 infections.