Brazil is currently battling a growing outbreak of dengue fever just as the country prepares for its vibrant Carnival celebrations. Health officials are working tirelessly to contain the outbreak, which has seen a significant increase in cases compared to the same period last year. The surge in dengue cases is not unique to Brazil, as experts warn of a global increase in the disease, potentially fueled by climate change.
Dengue fever, also known as “breakbone fever” due to the severe muscle pain it causes, is caused by viruses transmitted through the bites of infected female mosquitoes, particularly the highly invasive Aedes aegypti. It is estimated that around 400 million people worldwide are infected with dengue each year, with half of the world’s population living in areas at risk of outbreaks.
The majority of dengue infections are asymptomatic or mild, with only around 25% of infected individuals experiencing flu-like symptoms such as fever, rash, headache, nausea, and vomiting. These symptoms often lead to confusion with other illnesses. However, approximately 1 in 20 people who become sick with dengue will develop severe dengue, a potentially fatal medical emergency that requires hospitalization. Severe dengue can cause severe muscle pain, shock, internal bleeding, and organ damage.
Currently, there is no specific medicine to treat dengue, and for most people, the disease will resolve on its own after a week or two. Rest, hydration, and the use of fever reducers and painkillers can help manage the symptoms. However, blood thinning drugs like aspirin and ibuprofen should be avoided. Without proper medical treatment, the mortality rate of severe dengue can be as high as 20%. Access to care and maintaining the patient’s body fluid volume are crucial in reducing the fatality rate.
In response to the outbreak, Brazil has launched a mass vaccination campaign to control the spread of dengue. Several states have declared emergencies, and troops have been deployed to eliminate breeding hotspots for mosquitoes. The country’s health ministry reported nearly 365,000 cases in the first five weeks of 2024, four times the number from the same period last year. The outbreak has already resulted in 40 confirmed deaths, with 265 more under investigation.
The situation in Brazil is part of a global upsurge in dengue cases that has alarmed health officials. In 2023 alone, there were over 6 million dengue cases and over 6,000 dengue-related deaths reported worldwide. The European Centre for Disease Prevention and Control highlighted that infections were reported from 92 different countries and territories, with the Americas being the most affected region. Countries such as Brazil, Bangladesh, Mexico, Peru, and Burkina Faso were identified as infection hotspots. The agency also warned of an increase in diseases carried by the same mosquitoes, including Zika and chikungunya.
While dengue cases in the United States are relatively rare, with 2,556 cases reported in 2023, experts caution that climate change could make the country more hospitable to the mosquitoes carrying the virus. Most cases in the US are linked to travel, but the potential expansion of the mosquito vectors’ range poses a concern.
Dengue is a significant global health issue, particularly in Asian and Latin American countries. Over the past 20 years, cases have risen eightfold, although improved reporting practices contribute to some extent to the alarming rise. Interestingly, global dengue cases appeared to have fallen during the Covid-19 pandemic due to pandemic restrictions preventing approximately 750,000 cases in 2020. However, the World Health Organization notes that the pandemic may have hampered reporting efforts in some countries.
The prevalence of dengue is of renewed importance as world leaders grapple with the growing climate crisis. Climate change could facilitate the spread of disease-carrying mosquitoes into new areas. Changes in weather patterns and flooding, particularly after hurricanes, pose challenges in preventing disease transmission. The mosquitoes that carry dengue and other pathogens like West Nile can multiply rapidly in floodwater and debris, posing a significant public health threat to those recovering from disasters.
One surprising fact about dengue is that there are four distinct types of virus that cause the disease. Infection with one type does not confer immunity against the others. In fact, prior dengue infection increases the risk of developing severe disease if infected with another variant. This phenomenon, which was once a contentious topic among scientists, is now believed to be due to the antibodies developed after infection actually aiding the new dengue variant virus in worsening the infection.
Efforts to develop a vaccine for dengue have been complicated by this increased risk of severe disease upon exposure to a different dengue variant. For many years, the only available vaccine has been for individuals who have previously been infected. However, a vaccine for those without prior infection is now available,
