Global Threat of Dengue Fever

Dengue fever (DF) is a rising threat among emerging infectious diseases. It is transmitted primarily by Aedes mosquitoes, particularly Ae. aegypti and Ae. albopictus. The dengue virus (DENV) is now a public health challenge for more than 100 countries, with nearly half the global population at risk. Scientists believe there are around 390 million dengue cases annually, with 96 million being symptomatic, underscoring the urgency of addressing this escalating crisis. Dengue's prevalence is mainly in tropical and subtropical regions, where approximately 70% of cases are concentrated in Asia. Rapid urbanization has exacerbated the situation, transforming cities into fertile breeding grounds for mosquitoes that are vectors for the dengue fever-causing virus transmission from infected to healthy individuals. In an era where global travel, urban sprawl, and climate change are inextricably linked, dengue fever's reach has expanded, facilitated by prolonged mosquito survival and extended transmission seasons.

Dengue fever is caused by four distinct serotypes: DENV-1, DENV-2, DENV-3, and DENV-4. The virus's primary transmission occurs through the bite of infected female Aedes mosquitoes, although secondary vectors have also been reported. The infection cycle initiates when mosquitoes, having fed on viremic hosts, disseminate the virus after an extrinsic incubation period (EIP) of 5-14 days.

Clinically, dengue presents a spectrum of manifestations, ranging from asymptomatic cases to severe, life-threatening conditions. Following an incubation period of 4-10 days, symptomatic DF typically begins with sudden flu-like symptoms, including fever, headache, muscle pain, and rashes. While many recover within a week, a significant number progress to severe dengue, characterized by dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS).

The World Health Organization's revised 2009 guidelines categorize dengue infections by severity:

1. Dengue without warning signs,
2. Dengue with warning signs and
3. Severe dengue.

Critical warning signs of dengue fever include:

• Persistent vomiting,
• Abdominal pain, and
• Mucosal bleeding
• High fever
• Headache
• Rashes

The disease progression involves a febrile phase, a critical phase marked by plasma leakage and risk of shock, and a convalescent phase. The critical phase, occurring around three days post-fever onset, is mainly highly morbid, with the potential for fatal outcomes due to disseminated intravascular coagulation, organ failure, and metabolic acidosis. The mounting threat of dengue fever demands a concerted global response. Public health strategies must prioritize mosquito control, surveillance, and community engagement to curb the spread. Innovations in vaccine development and antiviral treatments offer hope, but organizations such as WHO and other caring public health must accelerate their efforts. Equally crucial is addressing the broader issues of climate change and urbanization, which fuel dengue's spread.