Evaluation of the relationship between urban remote sensors and positivity patterns of Aedes Aegypti ovitramps in the cities of Mancora and Sullana, endemic cities of northern Peru.
Universidad Nacional de Piura
CI-Emerge, Center of Emerging Diseases and Climate Change Research. Universidad Nacional de Piura, Piura, Peru. Department of Public Health, Faculty of Health Sciences, National University of Piura, Urb. Miraflores S/N, 20002 Piura, Peru.
Carlos Culquichicon, M.D.
Carlos Culquichicon, M.D.
English, Spanish
8 weeks
Cities/Months Jan Feb Mar Apr May Jun Jul Augt Sep Oct Nov Dec
Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes
Type of Research Project
- Clinical Project with Laboratory work
What is the background of the project?
Arboviral infections cause a great burden in tropical and subtropical areas, even more so in multiple viruses transmitted by co-circulating Aedes Aegypti such as Dengue Fever (DENV), Zika (ZIKV) and Chikungunya (CHIKV). DENV has been endemic in the Piura region of northern Peru since 1998 and the 2017 outbreak was the largest on record, reporting almost 50,000 cases, more than half of the total cases in Peru. The city of Sullana, located in the northern coastal region of Piura-Peru, has a population of almost 215,875 people distributed over approximately 16 km2 (3) and was the city with the highest incidence of arbovirus in the last years in Peru. CHIKV and ZIKV have also emerged in Piura in this complex scenario with 2770 and 852 cases in 2018 to date, respectively. Since 2016, the Ministry of Health of Peru has initiated entomological surveillance of A. Aegypti using ovitramps, which generated evidence on infestation, distribution and density of eggs in endemic areas, with special attention on the north coast and the Amazon basin. The positivity rates of the ovitrampes and the density of the eggs are indicators of Aedes infestation and can be used to assess the impact of control, although it is not clear exactly how environmental and urban factors influence these indicators.
What is the aim of the project?
To evaluate the relationship between urban remote sensors and ovitramp (insect egg incubation simulator that allows to measure the density of oviposition and therefore to infer the population density of the adult insect in a specific territory) positivity patterns in communities of Sullana and Mancora, Peru, 2019-21.
What techniques and methods are used?
1. A comprehensive community mapping will be conducted to identify and geolocate all reluctant/abandoned households as well as business premises. The spatial data will be obtained from the RapideEye satellite data system at® with a spatial resolution of 5 meters per side, estimating roof areas in 200 meters radius hexagons. 2. Density patterns of space-time Aedes will be estimated using the space-time statistic Gi * Getis-Ord (space-time implementation). 3. All spatial analyses will be performed within R Studio® and packages for emerging hot spot analyses. In addition, the correlation between Ovitrampa positivity and urban factors will be estimated using multilevel linear regression models in R Studio®. 4. The enzyme-linked immunosorbent assay (ELISA) to detect dengue antibodies in human serum samples will be performed with Euroimmun ELISA (Euroimmun AG, Lübeck, Germany). 5. Nucleic acids will be extracted using the viral mini-kit QIAamp (Qiagen 52906) according to the manufacturer's instructions and converted to cDNA using serotype-specific primers in the 3' terminal segments. 6. The extracted DNA will be stored at -20 °C until real time PCR (Polymerase chain reaction) is performed. 7. Samples that are positive to conventional PCR will be run in real time PCR. 8. MiSeq libraries will be used for the preparation of genomic libraries which will be built using enzymatically fragmented samples, Nextera DNA indexes (Illumina FC-121-1011) and Nextera DNA preparation kits (Illumina FC-121-1030). 9. The qualitative data retrieved will be analyzed using descriptive inductive analysis. The seroprevalence and prevalence of dengue virus will be estimated using accurate binomial methods. In addition, bivariate and multivariate logistic regressions will be used to assess the association between demographic, environmental and urban variables to dengue seropositivity in humans. 10. The genomic sequences obtained will be aligned with previously reported sequences available in GenBank using CLUSTAL-W to identify the dengue species circulating in Piura and their genetic variability.
What is the role of the student?
- The student will observe the practical experiments but will be highly involved in the analysis of the results
- If the project includes “lab work”
- the student will take active part in the practical aspect of the project
- The tasks will be done under supervision
What are the tasks expected to be accomplished by the student?
Literature survey for a project that may have been taken up again. Experimentation in the lab. Execution of ELISA tests (enzyme-linked immunosorbent assay) for the detection of antibodies in human serum with Euroimmun ELISA. Writing a paper or report. Epidemiological field operations or logistical implementation. Thermal cycler handling for conventional and real time PCR (Polymerase Chain Reaction) runs. Molecular characterization of dengue serotypes identified.
Will there be any theoretical teaching provided (preliminary readings, lectures, courses, seminars etc)
Preliminary readings related to the research project given on the first day. Training for epidemiological field logistics Training in report writing Laboratory supervision Monitoring for review of progress and/or doubts These activities will be provided by the tutor and the scientific advisors of the local association. We would like to have a videocall interview with the student before his/her exchange In case the student makes the exchange in May the duration will be until June.
What is expected from the student at the end of the research exchange? What will be the general outcome of the student?
- The student will prepare a poster
- The student will prepare a scientific report
What skills are required of the student? Is there any special knowledge or a certain level of studies needed?
Highly proactive, excellent teamwork performance. Basic handling of a thermal cycler. Management in the realization of ELISA tests. Basic knowledge in the use of statistical programs such as stata or R. Subjects passed: Epidemiology, Biostatistics,
Are there any legal limitations in the student’s involvement
Type of students accepted
This project accepts:
- Medical students
- 1. Rodriguez-Morales AJ; Villamil-Gómez WE; Franco-Paredes C. The arboviral burden of disease caused by co-circulation and co-infection of dengue; chikungunya and Zika in the Americas. Travel Medicine and Infectious Disease. 2016;14(3):177-9.
- 2. Palma-Pinedo H; Cabrera R; Yagui-Moscoso M. Factores detrás de la renuencia al control vectorial del dengue en tres distritos del norte del Perú.
- 3. Palma-Pinedo H; Cabrera R; Yagui-Moscoso M. Factores detrás de la renuencia al control vectorial del dengue en tres distritos del norte del Perú. Revista Peruana de Medicina Experimental y Salud Publica. 2016;33:13-20.