Why in News? Dengue cases are skyrocketing in Latin America and Caribbean as more than 5.9 million cases were reported from January-April 2024.

What’s Happening? Brazil is the worst affected country with 4.2 million cases and more than 2,000 deaths by dengue in a single year. Many of Brazil’s states have declared a state of emergency along with Peru and Puerto Rico. Countries like Uruguay and Chile, which had never been seriously affected, have been badly hit.

Reasons-

• Soaring Temperatures- because of global warming have led to more frequent and extreme weather events; increased mosquito population as mosquitoes thrive in warmer temperatures; and extended mosquito seasons allowing a longer period for transmission.
• El Niño- which leads to abnormal warming of surface waters in equatorial Pacific Ocean, has increased temperatures even more across the region.
• Extreme Weather Events- Untimely rainfall, storms, flooding, and rising sea levels create shallow, stagnant pools of water for bugs to thrive. During drought, people collect and save water in containers which provide breeding places for mosquitoes.
• Rapid Urbanization- Latin America’s shantytowns have become breeding grounds as people store water in open tanks. Piles of uncollected rubbish also serves as a mosquito mecca.

Status of Dengue Vaccines- Dengue virus has four strains and the main challenge for scientists is to develop an affordable vaccine which works against all strains because available vaccines are either expensive (Qdenga developed by Japan costs $115per dose in Europe) or have serious limitations (Dengvaxia by French Pharma company can be administered only to ones already infected by dengue). A new single shot dengue vaccine created National Institutes of Health (NIH), USA which promises strong immunity, is undertrial. Serum Institute of India is also testing a single-shot dengue vaccine based on NIH data.