Rapid spread of the emerging cosmopolitan genotype of dengue virus serotype 2, and expansion of dengue virus serotype 1 genotype V in Peru

Current and Future Spatial Distribution of the Aedes aegypti in Peru Based on Topoclimatic Analysis and Climate Change Scenarios

Dengue, a febrile disease that has caused epidemics and deaths in South America, especially Peru, is vectored by the Aedes aegypti mosquito. Despite the seriousness of dengue fever, and the expanding range of Ae. aegypti, future distributions of the vector and disease in the context of climate change have not yet been clearly determined. Expanding on previous findings, our study employed bioclimatic and topographic variables to model both the present and future distribution of the Ae. aegypti mosquito using the Maximum Entropy algorithm (MaxEnt). The results indicate that 10.23% (132,053.96 km2) and 23.65% (305,253.82 km2) of Peru's surface area possess regions with high and moderate distribution probabilities, respectively, predominantly located in the departments of San Martín, Piura, Loreto, Lambayeque, Cajamarca, Amazonas, and Cusco. Moreover, based on projected future climate scenarios, it is anticipated that areas with a high probability of Ae. aegypti distribution will undergo expansion; specifically, the extent of these areas is estimated to increase by 4.47% and 2.99% by the years 2070 and 2100, respectively, under SSP2-4.5 in the HadGEM-GC31-LL model. Given the increasing dengue epidemic in Peru in recent years, our study seeks to identify tools for effectively addressing this pressing public health concern. Consequently, this research serves as a foundational framework for assessing areas with the highest likelihood of Ae. aegypti distribution in response to projected climate change in the second half of the 21st century.

Genotypic diversity and molecular characterization of DENV-2 in a Peruvian endemic region from 2016 to 2022: displacement of American/Asian genotype

Background

Dengue is the most prevalent acute febrile disease with serious clinical consequences in the tropical and subtropical regions of Asia and America. In Peru, it represents a significant public health issue due to its hyperendemic nature, with serotype 2 (DENV-2) being the predominant serotype that leads to the most severe clinical manifestations of the disease. This study focuses on the molecular characterization and analysis of the intraserotypic diversity of DENV-2 circulating in the endemic region of Cajamarca.

Methods

A total of 3,967 blood serum samples from patients with acute febrile illness (AFI) were analyzed between 2016 and 2022 to detect DENV and DENV-2 using real-time RT-PCR. The viral envelope (E) gene was then sequenced using the Sanger method. Finally, phylogenetic reconstruction was conducted using the maximum likelihood method.

Results

A total of 32 complete sequences of the envelope gene were obtained, and the phylogenetic and characterization analyses of the amino acid sequences revealed that, during the period from 2016 to 2022, two DENV-2 genotypes circulated: the Am/As genotype and the cosmopolitan genotype in lineages 2 and C, respectively.

Conclusion

Similarly, our findings showed that every studied outbreak was characterized by novel autochthonous variants of the Am/As genotype and by an imported variant of the cosmopolitan genotype; this demonstrates a temporal distribution of intraserotypic variability that indicates the displacement of the Am/As genotype around 2021 and the establishment of the cosmopolitan genotype. The need for ongoing genetic or genomic surveillance of the cosmopolitan virus arises in order to understand its distribution and diversification patterns in Peru.