May 30 (Reuters) - Dengue cases have substantially increased in the Americas this year, the World Health Organization (WHO) said on Thursday, which indicates the mosquito-borne viral illness remains a high-risk threat to public health.

The UN agency said the number of cases in the Americas exceeded 7 million by the end of April, already surpassing the annual high of 4.6 million in 2023.

In comparison, over 7.6 million dengue cases and about 3,000 deaths were reported globally during the same period.

Brazil, Argentina and Paraguay have been hit the hardest by dengue among 46 countries in North and South America.

In March, head of the Pan American Health Organization Dr. Jarbas Barbosa da Silva said this will probably be the worst dengue season they will have.

Even widespread vaccination would not have an immediate impact on interrupting the ongoing outbreak, Barbosa has warned.

Dengue symptoms include fever, headaches, vomiting, skin rashes, as well as muscle and joint pain. In some cases, it can cause a more severe hemorrhagic fever, resulting in bleeding that can lead to death.

Most dengue cases are usually seen between February and May. (Reporting by Christy Santhosh in Bengaluru; Editing by Shinjini Ganguli)