Individual-based dengue virus surveillance in Aedes aegypti mosquitoes concurrently collected with suspected patients in Tarlac City, Philippines

Abstract Background: Vector control measures are critical in the prevention and reduction of dengue virus (DENV) transmission. In this context, an effective vector control is reliant not only on the knowledge of mosquito abundance, but also on the timely and accurate detection of mosquito infection. Mosquito-based virus surveillance programs typically rely on a pool-based mosquito testing, although whether individual-based mosquito testing could represent a feasible alternative is not largely studied. Applying an individual-based mosquito testing approach, we conducted a one-month DENV surveillance of adult Aedes (Ae.) aegypti mosquitoes around households of suspected dengue patients during the 2015 dengue peak season in Tarlac City, Philippines to more accurately assess the mosquito infection rate and identify the DENV serotypes and genotypes concurrently co-circulating in mosquitoes and patients.Methods: We performed a one-step multiplex real-time reverse transcription-polymerase chain reaction (RT-PCR) assay for the simultaneous DENV detection and serotyping in patients and individual female Ae. aegypti mosquito. Additionally, we performed sequencing and phylogenetic analyses to further characterize the detected DENVs in mosquitoes and patients at the genotype level.Results: We collected a total of 583 adult Ae. aegypti mosquitoes; of which, we individually tested 359 female mosquitoes for the presence of DENV. Ten (2.8%) among the 359 female mosquitoes were positive for the presence of DENV. We detected DENV-1, DENV-2, and DENV-4 in the field-collected mosquitoes, which were consistent with the serotypes concurrently infecting patients. Sequencing and phylogenetic analyses of the detected DENVs based on the partial envelope (E) gene revealed three genotypes concurrently present in the sampled mosquitoes and patients during the study period, namely: DENV-1 genotype IV, DENV-2 Cosmopolitan genotype, and DENV-4 genotype II.Conclusions: In this study, we demonstrate the utility of the one-step multiplex real-time RT-PCR assay in the individual-based DENV surveillance of mosquitoes. Our findings reinforce the significance of detecting and monitoring virus activity in local mosquito populations, which is critical for dengue prevention and control activities.

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Individual-based dengue virus surveillance in Aedes aegypti mosquitoes collected concurrently with suspected patients in Tarlac City, Philippines

10.21203/rs.3.rs-56950/v2 ◽

2020 ◽

Author(s):

Jean Claude Balingit ◽

Thaddeus M. Carvajal ◽

Mariko Saito-Obata ◽

Maribet Gamboa ◽

Amalea Dulcene Nicolasora ◽

...

Keyword(s):

Aedes Aegypti ◽

Dengue Virus ◽

Vector Control ◽

Real Time ◽

Phylogenetic Analyses ◽

Rt Pcr ◽

Pcr Assay ◽

Virus Surveillance ◽

One Step ◽

Mosquito Infection

Abstract Background: Vector control measures are critical in the prevention and reduction of dengue virus (DENV) transmission. In this context, effective vector control is reliant not only on knowledge of mosquito abundance, but also on the timely and accurate detection of mosquito infection. Mosquito-based virus surveillance programs commonly rely on pool-based mosquito testing, but whether individual-based mosquito testing could represent a feasible alternative is not largely studied. Applying an individual-based mosquito testing approach, we conducted a one-month DENV surveillance of adult Aedes aegypti mosquitoes around households of suspected dengue patients during the 2015 dengue peak season in Tarlac City, Philippines to more accurately assess the mosquito infection rate, and to identify the DENV serotypes and genotypes concurrently co-circulating in mosquitoes and patients. Methods: We performed a one-step multiplex real-time RT-PCR assay for the simultaneous detection and serotyping of DENV in patients and in individual female Ae. aegypti mosquito. Additionally, we performed sequencing and phylogenetic analyses to further characterize the detected DENVs in mosquitoes and patients at the genotype level. Results: We collected a total of 583 adult Ae. aegypti mosquitoes, of which we tested 359 female mosquitoes individually for the presence of the DENV. Ten mosquitoes (2.8%) from amongst 359 female mosquitoes were confirmed to be positive for the presence of the DENV. We detected DENV-1, DENV-2, and DENV-4 in the field-collected mosquitoes, which were consistent with the serotypes concurrently infecting patients. Sequencing and phylogenetic analyses of the detected DENVs based on the partial envelope (E) gene revealed three genotypes concurrently present in the sampled mosquitoes and patients during the study period, namely: DENV-1 genotype IV, DENV-2 Cosmopolitan genotype and DENV-4 genotype II. Conclusions: In this study, we demonstrate the utility of a one-step multiplex real-time RT-PCR assay in individual-based DENV surveillance of mosquitoes. Our findings reinforce the importance of detecting and monitoring virus activity in local mosquito populations, which is critical for dengue prevention and control activities.

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Surveillance of dengue virus in individual Aedes aegypti mosquitoes collected concurrently with suspected human cases in Tarlac City, Philippines

Parasites & Vectors ◽

10.1186/s13071-020-04470-y ◽

2020 ◽

Vol 13 (1) ◽

Author(s):

Jean Claude Balingit ◽

Thaddeus M. Carvajal ◽

Mariko Saito-Obata ◽

Maribet Gamboa ◽

Amalea Dulcene Nicolasora ◽

...

Keyword(s):

Aedes Aegypti ◽

Dengue Virus ◽

Vector Control ◽

Real Time ◽

Phylogenetic Analyses ◽

Simultaneous Detection ◽

Rt Pcr ◽

Pcr Assay ◽

Denv Serotypes ◽

One Step

Abstract Background Vector control measures are critical for the prevention and reduction of dengue virus (DENV) transmission. Effective vector control is reliant not only on knowledge of mosquito abundance, but also on the timely and accurate detection of mosquito-borne infection. Mosquito-based virus surveillance programs typically rely on pool-based mosquito testing, although whether individual-based mosquito testing is a feasible alternative to this has not been widely studied. Applying an individual-based mosquito testing approach, we conducted a 1-month surveillance study of DENV in adult Aedes aegypti mosquitoes in homes of suspected dengue patients during the 2015 peak dengue season in Tarlac City, Philippines to more accurately assess the mosquito infection rate and identify the DENV serotypes and genotypes concurrently co-circulating in mosquitoes and patients there. Methods We performed a one-step multiplex real-time reverse transcription-polymerase chain reaction (RT-PCR) assay for the simultaneous detection and serotyping of DENV in patients and individual female Ae. aegypti mosquitoes. Additionally, we performed sequencing and phylogenetic analyses to further characterize the detected DENV serotypes in mosquitoes and patients at the genotype level. Results We collected a total of 583 adult Ae. aegypti mosquitoes, of which we individually tested 359 female mosquitoes for the presence of DENV. Ten (2.8%) of the 359 female mosquitoes were positive for the presence of DENV. We detected DENV-1, DENV-2, and DENV-4 in the field-collected mosquitoes, which was consistent with the serotypes concurrently found in infected patients. Sequencing and phylogenetic analyses of the detected DENV serotypes based on the partial sequence of the evelope (E) gene revealed three genotypes concurrently present in the sampled mosquitoes and patients during the study period, namely DENV-1 genotype IV, DENV-2 Cosmopolitan genotype, and DENV-4 genotype II. Conclusions We demonstrated the utility of a one-step multiplex real-time RT-PCR assay for the individual-based DENV surveillance of mosquitoes. Our findings reinforce the importance of detecting and monitoring virus activity in local mosquito populations, which are critical for dengue prevention and control.

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