[dalke]

How do you know that's true about Dengue? http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3510884/ (from Indian J Med Res. 2012 Sep; 136(3): 373–390. ) says:

> The epidemiology of dengue fevers in the Indian subcontinent has been very complex and has substantially changed over almost past six decades in terms of prevalent strains, affected geographical locations and severity of disease. The very first report of existence of dengue fevers in India was way back in 1946[15]. Thereafter, for the next 18 years, there was no significant dengue activity reported anywhere in the country. In 1963-1964, an initial epidemic of dengue fever was reported on the Eastern Coast of India[7,16–20], it spread northwards and reached Delhi in 1967[21] and Kanpur in 1968

then continues with many more recent epidemics of Dengue in India throughout the decades.

I can think of several other hypotheses, besides a rise in mosquito-transmitted diseases, which can fit your observation:

1) you didn't pay attention to it 15-20 years ago, or your memory has faded, 2) other diseases, like polio and malaria, were more significant so played a larger role in health reporting, 3) people and news sources talk more about health issues now than then, 4) official counts which were deliberately under-stated are now becoming more realistic.