Projects | Nsa Dada, PhD

Mosquito Microbiome Consortium

Tue, 17 Nov 2020 00:00:00 +0000

G-AVENIR

Mon, 27 Apr 2020 00:00:00 +0000

Links between microbes and insecticide resistance in mosquito populations

Mon, 27 Apr 2020 00:00:00 +0000

Overview

It is no coincidence that the stall in malaria control progress over the past half decade overlaps with the scale up of insecticide-based malaria vector control tools, and the increasing prevalence and intensity of insecticide resistance in malaria mosquito populations. A better understanding of the mechanisms underlying insecticide resistance is thus needed to mitigate its threat to malaria control. So far, insecticide resistance research has focused on mosquito biology, behavior, and genetics. But mosquitoes, like all other living organisms, harbor microbes that influence their biology, behavior, and genetics.

Where we’ve worked so far

We hypothesized that the mosquito microbiome could be contributing to resistance following evidence in agricultural pest insects. Focusing on malaria vectors across Latin America and Sub-Saharan Africa; including Anopheles albimanus, An. gambiae s.s. and An. coluzzii, we studied how insecticide exposure; and resistance phenotypes, intensity, and genotype (kdr mutations), affect mosquito microbiota composition. Across all locations, Anopheles species, and insecticides considered, results consistently show significant mosquito microbiota alterations due to all factors tested except kdr mutations, which was fixed in the population studied regardless of insecticide resistance phenotype. Results also show specific microbes and putative microbial functions associated with either insecticide resistance or susceptibility. Of particular note are significantly higher abundance of Serratia in susceptible mosquitoes regardless of Anopheles species, location or insecticide class; and Lysinibacillus in pyrethroid resistant mosquitoes regardless of Anopheles species or location. Serratia is a known insect pathogen, and its pathogenicity could compromise the host’s ability to withstand insecticide exposure. Similarly, the pyrethroid-degrading ability of Lysinibacillus may contribute to resistance.

The figure below provides a summary of what we know so far

Furthermore, alteration of microbial composition due to insecticide exposure is suggestive of selection pressure on the mosquito microbiome that likely favors the resistance phenotype. Conversely, the identification of pathogenic microbial taxa in susceptible mosquitoes suggests a cause of insecticide susceptibility. Together, these findings suggest an underlying microbial mechanism of insecticide resistance. The lack of association between host insecticide genotype and microbial composition suggests that this microbial mechanism is likely of a metabolic nature that may not be related to known resistance-associated host genetics. Further work is being conducted to elucidate this microbial mechanism of insecticide resistance.

Please see below for publications associated with this project.

Collaborators/Partners

Kenya

Diana Omoke (KEMRI & KU)
Ezekiel Mugendi Njeru (KU)
Mathew Kipsum (KEMRI)
Samson Otieno (KEMRI)
Edward Esalimba (KEMRI)
Eric Ochomo (KEMRI)

Mexico

Pablo Manrique-Saide (UADY)
Azael Che-Mendoza (UADY)
Sergio Dzib Florez (UADY)
Lucio Ariel Alcocer Coronado (SSY)
Leonardo Daniel Ku Caamal (SSY)
Gilberto Castillo Chi (SSY)

Peru (Instituto Nacional de Salud)

Jesus Pinto

Benin (Tropical Infectious Diseases Research Centre)

Wassiyath Agnikè Mousse
Luc Djogbénou

Cote d’Ivoire (Centre Suisse de Recherches Scientifiques)

Edi Constant

UK (London School of Hygiene and Tropical Medicine)

Bethanie Pelloquin
Louisa Messenger

Italy (Sapienza University of Rome)

Verena Pichler
Beniamino Caputo

Guatemala

Norma Padilla (UVG)
Juan Carlos Lol (UVG)
Daniela Da’Costa (UVG)
Ana Christina Benedict (UVG)
Fransisco Lopez (UVG)
Pedro Peralta (UVG)
Adel Mejia (UVG)
Alfonso Salam (UVG)
Nelson Jimenez (MSPAS)
Ricardo Valle (MSPAS)
Ricardo Santos (MSPAS)

USA (CDC)

Audrey Lenhart
Kelly Liebman
Nicole Dzuris
Mili Sheth
Core Facility
Scientific Computing team
Entomology branch
Insecticide Resistance & Vector Control Team

Funding and support

Engage: Global Health. ASTMH 67th Annual Meeting, New Orleans, USA

Thu, 27 Apr 2017 00:00:00 +0000

Engage: Global Health. ASTMH 67th Annual Meeting, New Orleans, USA

ASTMH’s inaugural public health outreach event comprising fifteen stations showcasing different elements of the work we do as scientists and healthcare professionals in the field of tropical medicine.

I co-led the ‘There’s DNA everywhere’ station, where I demonstrated DNA extraction from strawberries to over 200 visiting high school students, their teachers/chaperones

Effects of microbes on Aedes aegypti infestation in domestic water containers

Mon, 01 Feb 2010 00:00:00 +0000

As part of a larger project aimed at understanding the links between dengue and diarrheal diseases, and how control measures for both can be integrated, I developed and led work on the relationships between dengue vector infestation and fecal contamination in household water storage containers. We focused on rural and suburban villages in northeastern Thailand and the south of Lao People’s Democratic Republic (Laos). Specific questions that I was interested in answering included whether:

there was any relationship between contamination levels of fecal bacteria and numbers of Aedes pupae (as a proxy for dengue transmission risk) in household water containers, and how this relationship varied by type of container
there were any differences in microbiota composition between immature Aedes aegypti and water from their breeding containers

I utilized a combination of classical and molecular biology/microbiology tools to quantify and characterize mosquito infestation and bacterial communities (using E. coli as a proxy for fecal contamination) in household water storage containers.

Results showed a positive correlation between fecal contamination levels and infestation levels of immature Aedes aegypti, suggesting that household water storage containers in these settings could represent a common denominator of dengue and diarrheal disease risk, and thus a potential target for integrated dengue and diarrheal disease control. Furthermore, Aedes aegypti larvae harbored bacteria acquired from their breeding habitat. However, their bacterial diversity was lower than those of their breeding water, suggesting the presence of a mechanism that controls microbial colonization within mosquitoes.

For more information please see associated publications below.

Funding and collaboration

Prevalence and intensity of STH infections in Sierra Leonean school children

Mon, 27 Apr 2009 00:00:00 +0000

Project description will be available shortly, please bear with me as I update the site. In the meantime, you can check out the publications associated with this project.

Spatio-temporal distribution of NTD vectors in Rhoko forest

Sun, 27 Apr 2008 00:00:00 +0000

Project description will be available shortly, please bear with me as I update the site. In the meantime, you can check out the publication associated with this project.