Climate change-induced warmer temperature, the El Nino effect and unequal rainfall, increased vector density and changes in precipitation patterns have encouraged vector-borne mosquitoes to spread their wings across the country with 2,34,427 cases of dengue already reported till November 30 this year. One month to go, the dengue infection is already on the higher side when compared to last year’s 2,33,251 cases of dengue and 1,93,245 incidents in 2021.
The number for this year is likely to be record high given that the cases remain low every year from January to July whereas maximum cases are reported from August to December.
While dengue cases have been increasing at a rapid rate in several states across the country, most of the surge is witnessed in West Bengal, Odisha, Jharkhand and Maharashtra. The issue was raised in Parliament on Friday with Union Minister of State for Health S P Singh Baghel in reply to a question saying that transmission of dengue happens round the year in many states. However, cases increase during monsoon and continue till the post-monsoon season due to the abundance of vector breeding sites.
“For dengue transmission, environmental factors namely rainfall, humidity and temperature are mainly responsible. In the current year, due to the global climate change, El Nino effect and unequal rainfall, increased vector density led to an increase in the number of dengue cases reported across the country in the current year,” Baghel said.
On the development of a vaccine against dengue, he said it is very challenging mainly due to the existence of four different serotypes with no cross-protection, no well-established animal models to understand the immunopathogenesis of disease, no established correlates of protection and lack of good immunological assays.
“The WHO target product profile for dengue vaccine is not yet available, as informed by the Indian Council of Medical Research (ICMR). The ICMR has recently signed an MoU with Panacea Biotec and Serum Institute of India for clinical trials of a dengue vaccine candidate,” the minister stated.
The ICMR has been working on creating awareness through its research institutions in the form of outreach programmes and training and awareness programmes among masses through public lectures, live demonstrations, training and research, he said.
The ICMR is using the latest technologies like remote sensing and geographical information systems for risk mapping of areas and planning interventions, Baghel added.
According to health experts, most people infected with dengue show flu-like symptoms, ranging from relatively mild to very unpleasant, with fever, headache and joint pain. In more severe cases, though, blood vessels can become damaged by the virus, allowing blood to leak into the surrounding tissues.
This condition, known as dengue haemorrhagic fever, can produce bruising, and bleeding from the nose and gums. It can ultimately lead to organ failure and death as the body slips into shock.
The principal agent, or vector, in the transmission of dengue, is the Asian Tiger mosquito Aedes aegypti, although its cousin Aedes albopictus is also capable of spreading the virus, as per health experts.