ANTI-VeC

Title: The Impact of feeding method on Anopheles mosquito midgut microbiota and P.falciparum infection rates

Principal Investigator: Mara Lawniczak (Wellcome Sanger Institute)

Co Investigator 1: Arthur Talman (Wellcome Sanger Institute)

Co Investigator 2: Abdoulaye Djimde (University of Science, Techniques and Technologies of Bamako, Mali)

Project Summary:

Malaria is solely transmitted through mosquitoes. Parasites invading the mosquito midgut can encounter environmental variation important in determining infectiousness of the parasite to the mosquito. Of particular interest is the mosquito gut microbiome, which is majorly altered during blood feeding. Current experiments looking into the importance of host microbiome and more generally measuring parasite transmission success typically use mosquitoes fed on an artificial membrane system that may not adequately represent natural skin feeding.

We propose to establish whether mosquito feeding mode alters mosquito microbiota and infectivity of the parasite mosquitoes. We will do so by comparing direct skin feed infections that fully recapitulate the natural infection process to the gold standard membrane feeding assay using blood from the same donor. Midgut microbiota will be characterized by 16S sequencing of the dissected mosquito midgut at peak bacterial growth postfeed, and dissections of mosquitoes retained for 8-10 days postfeed will reveal parasite infection rates.

The project will initiate long-term multi- project collaboration between Mali and Europe and will likely produce pilot data required to obtain further funding. Finally, the intellectual and logistics links created as part of this project are likely to benefit several young scientists currently seeking independent positions. In summary, this project will significantly enhance capacity in the field of medical entomology in Mali for scientists both local to the country and further afield.

Countries involved:

• Mali
• United Kingdom

Title: AnDAPT - Lab adaptation of Anopheles gambiae s.s

Principal Investigator:  Andrea Crisanti, (Imperial College London, UK)

Co-Investigator: Sekou Fantamady Traore, (University of Science, Techniques and Technologies of Bamako, Mali)

Project Summary:

Integrative approaches and creative new control and preventive tools and technologies are under development to reach the goal of the Global Malaria Eradication Programme. As one part of the integrative toolbox, newly developed vector control approaches aim to suppress mosquito population growth by releasing radiation-induced or genetically modified (GM) sterile mosquitoes (sterile insect technique SIT) or so-called gene-drive GM mosquitoes (e.g., paternal male biased strains) which origin from laboratory strains.

Insectary adaptation is very well known for several insect species and the transferability of results derived from laboratory experiments to a field situation is constantly debated. It is still unclear how closely the genome, the physiology and behaviour of laboratory-maintained individuals accurately match their wild counterparts. The proposed project AnDAPT aims to systematically explore the appearance and speed of lab adaptation at different biological levels in the malaria vector Anopheles gambiae s.s. collected from field in Mali.

The methodology focusses on monitoring changes in field collected Anopheles coluzzii s.s from Mali at genetic, phenotypic (e.g. ecophysiology) and behavioural level before and during rearing under insectary conditions in small and large sized cages. To distinguish genetic/phenotypic changes due to insectary bottleneck and inbreeding from those resulting for laboratory selection, a wild type field population of An. coluzzii s.s. is splitted into several replicate lines introducing the same number of adult mosquitoes into three small cages and two large cages. Each colony is allowed to diverge genetically from the original population source for 10 generations (~ 9 months). The quantity and quality of genetic/phenotypic/behavioral changes affected by bottleneck plus inbreeding should vary across replicates, whilst character changes resulting from lab selection should be stable and detectable in all replicates after 9 months. In addition, variation of genes with putative implication in male-female mating interaction and under lab selective pressure should exhibit a gradient distribution passing from small to large sized cages.

The data generated in the proposed project AnDAPT may help to support new approaches in genetic vector control which strongly depend on the ecophysiological performance, survival, and the mating behaviour of laboratory-reared mosquitoes in the field.

Countries involved:

• United Kingdom
• Mali

Title:   Role of insect-specific flaviviruses and immune priming in arbovirus transmission blocking in mosquitoes

Principal Investigator: Jandouwe Villinger (International Centre of Insect Physiology and Ecology)

Co Investigator 1: Seth Barribeau (University of Liverpool)

Co Investigator 2:  David Tchouassi (International Centre of Insect Physiology and Ecology)

Project Summary:

Vertically transmitted insect-specific flaviviruses (ISFVs), which do not infect mammals, are key to understanding the evolution of flaviviruses and, similar to Wolbachia, may potentially be exploited to control arbovirus transmission in blood-feeding insects.  Indeed, some ISFVs inhibit, whereas others enhance, replication of arboviruses in mosquito cells and/or mosquitoes.  The underlying mechanisms by which ISFVs modulate mosquito vectorial capacity remain poorly understood.  As ISFVs are both prevalent and critical to the transmission epidemiology of medically important flaviviruses, a better understanding of their role in altering arbovirus replication in mosquitos is essential.

ISFVs may modulate mosquito vectorial capacity either by directly and competitively preventing the establishment of subsequent arbovirus superinfections, or via host immune primed responses.  We propose to investigate how ISFVs modulate mosquito vectorial capacity using transcriptome sequencing to characterise both vector and viral gene expression responses and identify underlying mechanisms by which ISFVs affect the establishment of subsequent arbovirus superinfections.

This study will critically inform the potential of ISFVs and immune priming for blocking pathogen transmission in mosquitoes.

Countries involved:

• Kenya
• United Kingdom

Title: A Novel Malaria Transmission Blocking Strategy: Microsporidian Symbionts of Anopheles Mosquitoes

Principal Investigator: Jeremy Herren (International Centre of Insect Physiology and Ecology)

Co Investigator 1: Steven Sinkins (University of Glasgow)

Co Investigator 2: Mara Lawniczak (Wellcome Sanger Institute)

Project Summary:

We have discovered a novel microsporidian symbiont (microsporidia MB) that prevents the malaria mosquito (Anopheles gambiae) from transmitting the malaria parasite. 

The proposed research aims to study anopheles- microsporidia MB symbiosis and to determine how it can be usefully disseminated into mosquito populations to decrease their capacity to transmit malaria.  The multi-faceted approach involves an in-depth characterisation of microsporidia MB - host interactions on several levels.  Investigating microsporidia MB transmission dynamics and will enable us to determine the potential strategies that could be used to spread this symbiont through anopheline populations. 

In addition, we will examine the relationship between transmission routes and the malaria transmission blocking phenotype.  The proposed research will greatly improve our understanding of microsporidia MB - anopheline symbiosis and advance the prospect of utilising it to control the spread of vector borne disease.

Countries involved:

• Kenya
• United Kingdom

Title:  Targeted disruption of the steroid hormone inactivation pathway in Anopheline Mosquitos for malaria control

Principal Investigator: Mark Paine (Liverpool School of Tropical Medicine)

Co Investigator 1:  Luc Salako Djogbenou (University of Abomey-Calavi)

Co Investigator 2: Hanafy M Ismail (Liverpool School of Tropical Medicine)

Co Investigator 3: Gareth Lycett (Liverpool School of Tropical Medicine)

Project Summary:

Malaria, transmitted by Anopheline mosquitoes, remains a major cause of death worldwide.  At last count (2016) there 216 million malaria cases and 445,000 deaths, mainly in low and middle-income countries (LMIC), predominantly in Sub Saharan Africa (~80%).  Given the dependence of the malaria interventions on mosquito control intervention and the escalating resistance to existing insecticides, new targets for vector control intervention are urgently needed to reduce the disease transmission.  Disrupting the vectorial capacity and fertility of anopheles mosquitoes using novel transgenic technologies can potentially lead to powerful new interventions to reduce malaria transmission. 

This project will validate new targets for genetic and chemical control of malaria-transmitting mosquitoes based on the ecdysone (20E) pathway.  Tight regulation of 20E peak activity coordinates mosquito blood feeding, mating and reproduction.  However, the ortholog to the essential 20E deactivation enzyme from Drosophila (CYP18A1) is absent in An. gambiae, yet present in An. funestus, the second major African malaria vector, and many other insects.  This suggest critical differences that might be exploited to control the major malaria vectors in Sub Saharan Africa. 

This project will characterise the role of the An. funestus CYP18A1, opening the field to define alternative pathway targets in An. gambiae, and build a better multidisciplinary relationship to develop new genetic and chemical methods of vector control.

Countries involved:

• United Kingdom
• Benin

Title:   Determining heritable microbe incidence, prevalence and impact on sandfly vector species

Principal Investigator: Greg Hurst (University of Liverpool)

Co Investigator 1: Jandouwe Villinger (International Centre of Insect Physiology and Ecology)

Co Investigator 2:  Damaris Matoke-Muhia (International Centre of Insect Physiology and Ecology)

Co Investigator 3: Claudia Ximena Moreno Herrera (Universidad Nacional de Colombia)

Co Investigator 4: Rafael Vivero (Universidad Nacional de Colombia)

Co Investigator 5: Gloria Cadavid (Universidad Nacional de Colombia)

Project Summary:

Heritable microbes - viruses, bacteria and protists that pass from a female insect to her progeny - are common in insects, and biologically important.  Carrying a heritable microbe may allow a blood feeding vector to live on a blood diet alone and may modify its ability to transmit pathogens.  Research on these symbionts has largely focused on Wolbachia/mosquito interactions, which has developed into a tool for controlling vector borne diseases (mainly dengue). 

This project will examine the symbiotic interactions in sandflies, and their potential to modify vector competence for Leishmania transmission.  We will establish the delivery of endosymbionts in sandfly vectors on Colombia and Kenya and evaluate the impact they have on the vector competence of their insect host.  Our work will concentrate on two microbes: Wolbachia and Rickettsia. 

Through the Project, we will develop a wider understanding of the symbionts of vectors, their potential biological effects, and their potential utility in control of vector borne infections that impact on the health and wellbeing of people in Lower and Middle Income countries.

Countries involved:

• United Kingdom
• Kenya
• Colombia

Title:  Functional genetics tools for Anopheles funestus: opening the door to genetic control and to an understanding of its vector competence (FunFuncGen) 

Principal Investigator: Tony Nolan (Liverpool School of Tropical Medicine)

Co Investigator: Charles Wondji (Centre for Research in Infectious Diseases)

Project Summary:

A way to introduce precise genetics into an organism is essential for understanding how genes determine key phenotypic characteristics.  In the case of mosquito vectors such a technology, can allow us to understand the genetic nature of traits that make it such a resilient transmitter of the malaria parasite. Half the world's population are at risk from malaria and every year and, despite recent interventions that have had some success, close to half a million people die, most of these children.  Anopheles funestus is significant vector of malaria in many areas of Sub Saharan Africa, often being the dominant species responsible for the majority of transmission in some areas.  Despite this, it is relatively poorly studied in the lab, in part because it can be difficult to rear in the laboratory, in part because a technology to genetically transform it has yet to be developed. 

This project will bring together two research teams with unique and complimentary experience in the rearing of anopheles funestus and in genetic transformation of mosquitoes, respectively.  We will work to establish from wild-caught mosquitoes new laboratory colonies of A. funestus, providing varied genetic populations as a resource for the scientific community.  We will use precise genome editing tools such as CRISPR, to cut almost any mosquito DNA sequence of choice to introduce desired sequence changes. Such a technology permits confirmation of the role of genetic sequences that might previously have been associated with important traits like human biting preference or insecticide resistance.  It will also open the way for genetic control tools such as gene drive that looks to introduce traits that affect a population's ability to transmit parasites, yet ensures these traits show preferential inheritance to that a population can be rapidly transformed.

Countries involved:

• United Kingdom
• Cameroon

Title: Should tsetse symbiont, S. glossinidius, be engineered to control African trypanosomiasis?

Principal Investigator: Alvaro Acosta-Serrano (Liverpool School of Tropical Medicine)

Co Investigator 1: Daniel Masiga (International Centre of Insect Physiology and Ecology)

Co Investigator 2: Lee Haines (Liverpool School of Tropical Medicine)

Project Summary:

Tsetse symbionts play a prominent role in fly biology by supplementing vitamins (which the fly is unable to make) into nutritionally-poor blood meal.  In other insects, symbionts can also contribute to environmental adaptation, provide defences towards pathogen and parasites, dictate male selection, and be exploited via a novel disease control strategy called paratransgenesis.   Paratransgenesis involves genetically engineering a bacterial symbiont to produce a protein within the insect that specifically stops the insect from being able to transmit disease. 

A suggested strategy to control the spread of African sleeping sickness (a fatal parasitic disease spread by tsestse) focuses on using a tsetse-specific symbiont (Sodalis glossinidious) for paratransgenic  disease control. We have  a lab and insectary-based evidence suggesting this bacteria species may not resistance to parasite infection, which would lead to higher disease transmission.

Our main goal is to identify how Sodalis glossinidius manipulate the fly into accommodating a parasite infection.  We want to identify what molecules Sodalis release, to understand why these molecules influence fly biology and to examine how this vector-symbiont-parasite relationship impacts disease prevalence in wild tsetse populations in Kenya.  Using the information, we will incorporate symbiont prevalence into current epidemiological models, thereby improving accuracy for identifying potential disease hotspots, which will help vector control teams prioritise interventions.

Countries involved:

• United Kingdom
• Kenya

Title: Effects of co-infection of Wolbachia and the entomopathogenic fungus metarhizium pingshaense in Aedes aegypti

Principal Investigator: Abdoulaye Diabete (Institut de Recherche en Sciences de la Sante)

Co Investigator 1: Etienne Bilgo (Institut de Recherche en Sciences de la Sante)

Co Investigator 2: Steve Sinkins (University of Glasgow)

Co Investigator 3: Maria Vittoria Mancini (University of Glasgow)

Project Summary:

Vector borne diseases (VBD) account for a significant proportion of the global burden of infectious disease.  Nearly half of the world's population is infected with at least one type of vector borne pathogen.  In Burkina Faso, despite substantial efforts devoted to controlling infectious diseases, in the last two years the country has been severely hit with dengue outbreaks.  The spread of insecticide resistance in the vector Aedes aegypti has challenged the standard public health approaches to control these diseases, hence the scientific community is calling for massive investments in new tools.

Wolbachia mediated transmission-blocking pathogens is one of the most promising novel strategies.  Wolbachia is an intracellular and maternally inherited bacterium.  Bacteria species from this genus not only increase mosquitoes' resistance to malaria parasites and arthropod-borne viruses, but they also reduce their fitness and reproductive capacities.  Several trials with Wolbachia transinfected Aedes to evaluate effectiveness in reducing dengue are underway.  Different Wolbachia strains introduced into Ae. aegypti have different properties; wAu is an extremely efficient dengue transmission blocker but does not induce cytoplasmic incompatibility, the main mechanism used by Wolbachia to spread through populations, so alternative spreading methods are needed if this strain is to be used in disease control.

We will investigate the possibility that Wolbachia confer protection against Metarhizium pathogenic fungi in Ae aegypti and thus assess whether fungi might be used to spread this strain of Wolbachia through populations.  We will also introduce Wolbachia into a local genetic background by backcrossing, and examine the effects on the most important parameters with respect to its potential future use for dengue control in West Africa.

Countries involved:

• Burkina Faso
• United Kingdom

Title: Into the Wild: New Models for Community Engagement with Mosquito Releases

Principal Investigator: Ann Kelly (King's College London)

Co Investigator 1: Fredros Okumu (Ifakara Health Institute)

Co Investigator 2: Javier Lezaun (University of Oxford)

Co Investigator 3: Prosper Chaki (Ifakara Health Institute / PAMCA)

Co Investigator 4: Givemore Munhenga (University of Witwatersrand)

Co Investigator 5: Brian B Tarimo (Ifakara Health Institute)

Co Investigator 6: Marceline Finda (Ifakara Health Institute)

Project Summary:

A collaboration between social scientists, public health practitioners, entomologists and vector biologists, this project seeks to formulate and test a set of principles for effective community engagement with novel vector control interventions, specifically those that involve the release of laboratory-altered insects. 

The project combines research into past experiences of insect releases, international guideline development via the Pan-Africa Mosquito Control Association, and proof-of-principle stakeholder engagement process in Tanzania.

The project seeks to develop new models for robust community engagement with novel vector control interventions, grounded in systemic social scientific research and extensive input from stakeholders.

Countries involved:

• United Kingdom
• Tanzania
• Kenya
• South Africa

   

Title: In the eye of the swarm: Mapping the acoustic landscape of mosquito disease vectors

Principal Investigator: Joerg Albert (University College London)

Co Investigator 1: Sarah Moore (Ifakara Health Institute)

Co Investigator 2: Marta Andres (University College London)

Co Investigator 3: Matthew Su (University College London)

Project Summary:

Sound plays an essential role in the courtship of all major mosquito disease vectors.  It has been known for some time that males use detection of conspecific flight tones to locate females.  Recently, more complex interactions involving frequency-modulated signals and distortion products have been suggested.  While it is clear, that both males and females use sound to locate and identify respective mating partners, how they actually do this is unclear. Complicating things further, mosquitoes mate within - often large - swarms.  Swarms of Anopheles gambiae can contain up to thousands of males, with only small numbers of females entering the swarm from the edges.  All of the previous work has ignored that these mating interactions occur in the context of these chaotic aggregations and has predominately measured interactions between isolated couples.  As an environment for acoustic communication the swarm has remained a mystery.

Our project explores the acoustic landscape of - and acoustic behaviours within - the mosquito swarm.  In the field, we will map the swarm's sound emissions using custom-designed microphone/playback arrays that can be introduced to swarms of anopheles gambiae.  In the lab, we will test the auditory (or behavioural) responses of individuals (or groups) of males and females to the recorded sound stimuli (creating 'virtual swarm copies' in the lab). 

These approaches will directly inform novel vector control methods (traps and mating disruption) and contribute to ongoing efforts by providing novel assessment of reproductive (acoustic) fitness of genetic modified mosquitoes before their mass-release in the field.

Countries involved:

• United Kingdom
• Tanzania