According to municipal reports, the three patients tested positive for the virus after conducting IgGm antibody tests through ELISA technology.
Of the 12 confirmed cases, nine are residents of Delhi, while three are from neighbouring states but are being treated in Delhi. Three cases have been confirmed from areas under the South corporation and two each from the North and East corporation areas. Last year, nine cases of dengue had been confirmed during the same period.
Municipal officials said there was no reason to anticipate a spike in cases this year. Every virus has annual cycles, so we are have been fumigating areas to control the spread of mosquitoes. With showers expected soon, we have doubled our efforts and issued instructions to hospitals to set up appropriate diagnostic tests. However, it is too early to say whether we will see a high number of cases this year, an official of the South corporation said.
Microbiologists say while anti-mosquito activities are important, the pattern of annual virus outbreaks in the past has shown that cases peaked every 2-3 years. Dengue has four strains. While Type I and III are the most common in Delhi, patterns change every few years. Last year we had identified considerable number of Type II for the first time since 1996, a microbiologist from AIIMS explained.
The Type II strain is known to cause severe symptoms such as haemorrhagic fever and shock. But after a few initial cases, we saw more of Type I and III last year. But if any strain is diagnosed late, especially after blood platelet levels start falling, it can lead to severe symptoms, the microbiologist said.
This year, serological tests are yet to be conducted to identify the strain of the virus.
Meanwhile,10 cases of malaria have been confirmed this year one in June against 28 cases last year, of which 11 were in June.
Malaria cases seem to be in control this year compared to the last few years. We are maintaining due vigilance but looking at trends from the last few years, we are likely to see a lull in malaria cases this year, a municipal corporation official explained.