Dengue cases soar to record high in the Americas with 12.6 million suspected cases: All you need to know

Dengue cases have witnessed an unprecedented uptick this year with a record 12.6 million suspected cases of the mosquito-borne disease reported this year, which is nearly three times the count seen last year, as per health officials. Climate change which is leading to warmer temperatures in the Americas is fueling an explosion of cases as mosquitoes are known to multiply in hot and humid conditions.
Additionally, amid this worrying trend, deaths due to dengue are also on rise, as per The Pan American Health Organization —the regional office of the World Health Organization in the Americas. The death count has registered a 200% increase compared to the last year. Around 7,700 deaths have been reported in the Caribbean and the Americas so far in 2024, while the count stood at 2,467 deaths in 2023. This is the highest toll since 1980 as per PAHO. The virus has surged worldwide since last year and spread to areas previously free of dengue, according to PAHO.
The dengue virus is transmitted to humans through the bites of infected female mosquitoes, primarily the

Aedes aegypti mosquito

. Mosquitoes can also become infected by people who are viremic with the dengue virus. The mosquitoes that spread dengue are active during the day.

Types of dengue

There are four types of

dengue serotypes

classified by 1, 2, 3, and 4. Serotype 3 has been dominating in Mexico, Central America and parts of the Caribbean in the second half of the year, according to Thais dos Santos, PAHO’s advisor on arboviral diseases.

Over the past 20 years, dengue virus serotype 3 (DENV-3), subtype III, has caused severe dengue hemorrhagic fever (DHF) outbreaks in Sri Lanka, East Africa, and Latin America. Phylogenetic analysis reveals that these geographically distant epidemics are linked, with the virus originating in the Indian subcontinent. A new variant of DENV-3, subtype III, appeared in Sri Lanka in 1989, spreading to Africa in the 1980s and Latin America in the 1990s.

According to ScienceDirect, a DENV-2 is more related to shock and hemorrhagic manifestations, followed by DENV-3, while DENV-1 presented milder clinical manifestations and DENV-4 as well.
It is to be noted that infection with one serotype doesn’t provide immunity from the other, which means you can develop

dengue symptoms

if infected with a different serotype.
Most persons infected with dengue viruses are asymptomatic or develop dengue fever (DF). Severe complications like DHF and dengue shock syndrome (DSS), develop only in a minority of infected people.

Symptoms of dengue

Symptoms of dengue may start showing typically 4–10 days after infection and the disease can last for 2–7 days. Symptoms may include high fever, severe headache, pain behind the eyes, muscle and joint pains, nausea, vomiting, swollen glands and rash. People may experience severe abdominal pain, persistent vomiting, rapid breathing, bleeding from gums or nose, fatigue or restlessness even after they recover from fever.
Individuals who are infected for the second time are at greater risk of severe dengue.
Severe dengue symptoms often come after the fever has gone away. They include severe abdominal pain, persistent vomiting, rapid breathing, bleeding gums or nose, fatigue, restlessness, blood in vomit or stool, being very thirsty, pale and cold skin, and feeling weak.

Dengue prevention

It is important to minimise mosquito exposure and breeding grounds. Since the mosquitoes that transmit dengue are active during the day, wearing clothes that cover as much of the body as possible and using mosquito repellents containing DEET, Picaridin, or IR3535 is crucial. Sleeping under mosquito nets, ideally treated with insect repellent, and installing window screens can provide additional protection.
To prevent mosquito breeding, eliminate stagnant water by properly disposing of waste, cleaning domestic water containers weekly, and applying insecticides to outdoor water storage. Environmental management, such as removing man-made habitats that collect water, is also vital. Early detection and proper care, including rest, hydration, and the use of acetaminophen for pain, can help manage symptoms if infected, but medical attention is essential for severe cases.