Dengue is the main Aedes-borne viral diseases with nearly 390 million annual dengue infections and 96 million (67–136 million) clinical cases [1]. This disease is caused by the dengue virus (DENV1, DENV2, DENV3, and DENV4) belonging to the Flavivirus genus. The dengue virus is transmitted to humans by a bite of an infected Aedes mosquito notably Ae. aegypti and Ae. albopictus. Dengue was previously considered as scarce in Africa in general probably due to the under-diagnosis and the similar symptoms with malaria which is endemic in the region.
Symptoms
It will be interesting to highlight that the common symptoms of dengue are fever, severe headaches, pain behind the eyes, severe joint and muscle pain, fatigue, nausea, and vomiting.
Outbreaks and Occurrences
However, during the two last decades there has been a rise in dengue cases reported in Cameroon [2-7] suggesting the modification of epidemiology of this disease. Coincidentally, the emergence of this virus in urban areas in Cameroon matches the introduction of Ae. albopictus in the country. Aedes albopictus is an invasive species which originates from south East Asia and was reported for the first time in Cameroon circa 2000 [8] while Ae. aegypti is indigenous in Africa and documented in Cameroon since 1950. You should know, there is no efficient vaccine and specific treatment against dengue, vector control remains the cornerstone to prevent and control outbreaks.
Our works at the Centre for Research in Infectious Diseases (CRID) about dengue virus is to characterise dengue vectors and establish the entomological risks of outbreak occurrence. Drawing from our work, we demonstrate that Ae. aegypti is present across Cameroon while Ae. albopictus has a distribution limited in the southern part of the country [9] suggesting a climate limitation of invasion of this species in the North.
Our research also demonstrates that both species breed mainly in discarded tanks and used tyres in Cameroon as in other Central African countries [10, 11]. Having assessed the ability of Ae. aegypti and Ae. albopictus collected in different ecological settings in Cameroon, our analysis showed that Ae. aegypti can easily transmit dengue in areas where both species are found. However, in the North notably in Maroua and Benoue, Ae. aegypti populations were found resistant to dengue transmission [12]. Our data revealed the variable level of susceptibility according to the population origin and insecticides tested except to organophosphates (temephos and fenithrotion) which were fully susceptible [13]. These data are relevant to plan arbovirus vector control programmes in Cameroon which is currently lacking and help in facilitating further works.
It is important to draw the attention of the Ministry of Public Health to the fact that the entomological risk of outbreak occurrence is real and it has become urgent to set up a programme to fight against abovirus vectors in Cameroon.
And to the population, while waiting for an arbovirus vector control programme to be put in place, it is important to take action by elimiating every container that is no longer in use as well as get rid of used tires. This will greatly help reduce the ovipositing sites of Aedes and therefore reduce the density of adult mosquitoes.
