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- Franco, L, et al.
(author)
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Dengue in Africa : sustained and silent circulation of multiple serotypes and genotypes, detected in travelers from 2010 to 2014
- 2015
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In: Tropical medicine & international health. - : Wiley-Blackwell. - 1360-2276 .- 1365-3156. ; 20:Suppl. 1, s. 107-108
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Journal article (other academic/artistic)abstract
- Introduction: Dengue is caused by 4 different related viruses, DENV 1 to 4, transmitted to humans via Aedes mosquitoes. The disease is endemic in more than 100 countries. In Africa, the estimated dengue burden is 15 million of clinical cases and about 48 millions of inapparent infections. However, dengue remains largely unrecognized in Africa. Due to the lack of laboratory confirmation, a febrile syndrome is frequently misdiagnosed as malarial infection. The circulation of different dengue serotypes is also poorly documented. However, some information is provided by reports of dengue infections in travellers returning from Africa. In the present study we attempt the identification of dengue serotypes and genotypes circulating in Africa from 2010 to 2014 detected in travellers returning to Europe.Methods: We collected samples from viraemic travellers returning from Africa who attended TropNet clinics in Europé from 2010 to 2014. Sequences of the Envelope gene were used to identify the serotype and genotype.Results: During the study period we identified 3 DENV serotypes circulating in Africa. DENV 1 strains were detected in East Africa in 2010 (Eritrea) and in 2012 (Kenia), whereas in Central Africa in 2013(Angola and DRC). Strains from East Africa were grouped within Asian genotype, close to virus isolated in previous years in Djibouti and Kenia; we found American /African genotype in Central Africa. Both genotypes have circulated in West Africa for many years. DENV 2 strains were detected in West Africa (Senegal) and in East Africa (Tanzania) in 2014. Dengue 2 from Tanzania belongs to cosmopolitan genotype, but form a distinct clade different from the old African group. However, DENV 2 from Senegal surprisingly fell into genotype America /Asia. To our knowledge this is the first time identified in Africa. Finally, DENV 3 was detected in 2010 in Mali and Burkina Faso and again in Burkina Faso in 2013. All DENV 3 belong to genotype III and form a cluster with the African strains identified since 2008.Conclusion: DENV 1 of both genotypes was identified previously in Africa indicating endemic transmission as well as with DENV 3. Meanwhile, a new DENV 2 appeared in Tanzania, introduced from South East Asia, and in Senegal from the Americas. These results confirm silent and sustained circulation of dengue in Africa and show the usefulness of travelers for sentinel surveillance to unmask the dengue problem in Africa.Disclosure: Nothing to disclose.
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| 2. |
- Franco, L, et al.
(author)
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Dengue serotypes and genotypes circulating in recent years in the Caribbean and imported to Europe
- 2015
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In: Tropical medicine & international health. - : Wiley-Blackwell. - 1360-2276 .- 1365-3156. ; 20:Suppl. 1, s. 104-105
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Journal article (other academic/artistic)abstract
- Introduction: Dengue viruses (DENV) are the most widespread arthropod-borne viruses endemic in the tropics and transmitted to humans through the bites of Aedes mosquitoes. Travelers can act as vectors to introduce DENV to uninfected areas or regions. Travelers can also serve as sentinels for ongoing outbreaks and dominating serotypes and genotypes in the source countries. We set out to describe the importation of dengue virus from the Caribbean via travelers to Europe.Methods: From 2011 to 2014, we collected samples from viraemic travelers returning from the Caribbean with confirmed dengue to 11 TropNet clinics in Europe that are participating in the DengueTools project. Sequences of the Envelope gene were used to identify serotype and genotype.Results: The main countries of importation were Barbados, Cuba, Dominican Republic, Guadeloupe, Haiti, Martinique, Netherlands Antilles and Puerto Rico. All 4 DENV serotypes were identified. DENV 1 strains were grouped within genotype V creating a new clade. All DENV 2 sequences clustered within a clade in the American/Asian genotype which was recently also identified in other Caribbean and Brazilian strains. DENV 3 strains were grouped within genotype III. All DENV 4 strains were phylogenetically grouped within a modern Caribbean basin clade in genotype II.Conclusions: Travelers provides unique insights into the global picture of circulating DENV strains. This study from the Caribbean region led to the identification of novel clades. Moreover, we were be able to detect dengue strains circulating in Cuba from 2011 to 2013, although officially no dengue was reported during that time period. Travelers serve as sentinels to provide timely information about current distribution of dengue serotypes and genotypes associated or not with outbreaks and track the spread of DENV strains in areas with scarce epidemiological information.Disclosure: Nothing to disclose.
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| 3. |
- Franco, L., et al.
(author)
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Molecular epidemiology suggests Venezuela as the origin of the dengue outbreak in Madeira, Portugal in 2012-2013
- 2015
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In: Clinical Microbiology and Infection. - : Elsevier. - 1198-743X .- 1469-0691. ; 21:7, s. 713.e5-713.e8
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Journal article (peer-reviewed)abstract
- An explosive epidemic occurred in Madeira Island (Portugal) from October 2012 to February 2013. Published data showed that dengue virus type 1 introduced from South America was the incriminated virus. We aim to determine the origin of the strain introduced to Madeira by travellers returning to Europe. Using phylogeographic analysis and complete envelope sequences we have demonstrated that the most probable origin of the strain is Venezuela.
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