VIROLOGY
Within Africa the similarity of common, non-specific clinical symptoms like malaria and other tropical febrile illnesses, limited laboratory diagnostic capacity, inadequate surveillance and case reporting may significantly underestimate the prevalence of dengue in these areas
unaffected by dengue.5 The WHO
suggests that since 2023 over five million cases and more than 5000 dengue- related deaths have been reported in over 80 countries.2
WHO online resources indicates areas affected and prevalence.2
Figure 1 taken from This clearly
shows that the dengue virus is on our doorstep. Interestingly Figure 1 also highlights
areas where the burden of disease is not well understood and may be significantly under reported.2
This is evident within
the African continent where the similarity of common, non-specific clinical symptoms like malaria and other tropical febrile illnesses, limited laboratory diagnostic capacity, inadequate surveillance and case reporting may significantly underestimate the prevalence of dengue in these areas.6 The WHO African regional office has endorsed a framework for integrated control, elimination and eradication of tropical and vector-borne diseases, with
the programme running until 2030.6 This programme alongside the regional global arbovirus initiative should give us a clearer picture of the burden of dengue and disease prevalence in the near future.6
Cases worldwide
Close to 80% of dengue cases have been reported in the Americas.2
On 29
March 2024 the Pan-American Health Organization (PAHO) reported a total of 4,569,464 dengue cases, which included 7665 severe cases leading to 2363 deaths within the Americas.7
The data
collected in 2024 indicate a continuation of a rise in cases, with 3,578,414 dengue cases, 2888 characterised as severe and 1039 deaths in weeks 1–12. This represents a more than three-fold rise compared to the same period in 2023.7 Figure 2 clearly indicates the recent rise in cases in the Americas, with the Southern cone region, which includes, Argentina, Chile, Uruguay and southern
states of Brazil seeing a continued significant rise in cases.7
The current
situation in the Americas has seen all types of dengue virus, DENV1 through DENV4 being identified throughout the outbreak.7
Local cases
Dengue is not considered endemic in the WHO European region, with current cases mainly being associated with travel to endemic areas. However, locally transmitted cases have been reported in Croatia, Israel, Italy, Portugal, Spain and even France.1 In 2023 three reported small autochthonous outbreaks were reported in Italy, France and Spain.6
Routine
testing without travel history and clinical suspicion is uncommon in these areas, suggesting the true number of cases is probably underestimated. As indicated the Aedes mosquito, the main vector of dengue virus in Europe, has been able to establish itself in southern Europe. These vectors have also been detected further north and within western Europe, and have the capacity to hibernate in the winter.6 Cold winters currently prevent year- round transmission. However, the effects of global warming, leading to flooding and stagnant water are creating favourable environments for these vectors within our region. It is interesting that we do not seem to have woken up to the threat that the Aedes mosquito and diseases it may carry poses, with most laboratories in the UK having to rely on reference laboratory facilities
Fig 1. Countries/territories/areas reporting autochthonous dengue cases (November 2022-November 2023). 30 JUNE 2024
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