Is dengue contagious, and how does it spread? - #8664

Dengue is primarily transmitted through the bite of infected mosquitoes, specifically the Aedes aegypti and Aedes albopictus species. It is not contagious between humans like some other viral infections; direct human-to-human transmission does not occur outside of mosquito vectors. In rare cases, dengue can be transmitted through blood transfusion, organ donation, or from a pregnant person to their fetus, but these are not typical methods of spread. Yes, there are four distinct strains of the dengue virus (DENV-1, DENV-2, DENV-3, and DENV-4), and a person can indeed become infected multiple times, with subsequent infections potentially causing more severe disease. Previous infection with one strain does not confer immunity against the others and can increase the risk of developing severe complications, such as dengue hemorrhagic fever or dengue shock syndrome, during subsequent infections. Climate plays a significant role in the spread of dengue. Warm and humid conditions favor the breeding and activity of mosquitoes, which can lead to higher transmission rates. This is why dengue outbreaks are more common in tropical and subtropical regions, and during warmer months. While dengue hemorrhagic fever can occur upon a person's first infection, it is more frequently associated with individuals who have had prior infections with a different strain. Severe manifestations are often seen during subsequent infections because of the immune response triggered by the first strain, which can enhance the severity of the disease. Regarding vaccines, there is indeed a dengue vaccine called Dengvaxia, which is recommended for individuals aged 9-45 years who have had at least one previous dengue virus infection. However, for those without prior exposure, there are increased risks associated with vaccination. Prevention through mosquito control remains the most effective strategy to avoid dengue, including using mosquito repellents, wearing long sleeves, and eliminating standing water where mosquitoes breed. If someone in your household has dengue, it is advisable for others to take precautions. This includes using mosquito nets, repellents, and ensuring that there are no mosquito breeding sites in and around the home to minimize the risk of bites from affected mosquitoes. If you have further questions or if you or someone you are in contact with is showing symptoms of dengue, such as high fever, severe headache, pain behind the eyes, joint and muscle pain, or rash, I recommend contacting a healthcare professional for assessment and advice on the next steps to take.