17th June 2024

Arboviruses

Arboviruses are simply arthropod-borne viruses. These include zika virus, chikungunya virus, and dengue virus. This section will focus on dengue, due to its prevalence and potential for life-threatening consequences.

Dengue, a flavivirus, is transmitted by the Aedes mosquito in the tropics and subtropics. The clinical manifestations of the virus are fever, arthralgia, and a distinctive maculopapular rash. The illness is usually self-limiting, though a small proportion of patients may develop severe, life-threatening dengue. Interestingly, past infection with one of the four serotypes of dengue increases the risk of subsequent severe dengue, likely by a process called Antibody Dependent Enhancement. This makes vaccine development difficult. The term “dengue haemorrhagic fever” was previously used to denote severe dengue, however this has been superseded by the most recent WHO classifications of dengue, with or without warning signs, and severe dengue. Serology can be used for formal diagnosis, though diagnosis in endemic regions can normally be made on clinical and laboratory findings. Leukopenia and thrombocytopenia are common. Treatment of dengue is purely supportive.

Image Source: WHO/IRIS (2009). 10665, Licensed under a creative commons licence. Available for free at: https://apps.who.int/iris/handle/10665/44188 (Accessed: 24 January 2024).