Scent Sensors Are New Target for Repellents To Curb Insect Vector-Borne Diseases

A model of the interactions among a host population, an insect-vector population, which transmits virus from hosts to hosts, and a vector predator population is proposed based on virus-host, host-vector, and prey (vector)-enemy theories. The model is investigated to explore the indirect effect of natural enemies on host-virus dynamics by reducing the vector densities, which shows the basic reproduction numbersR01(without predators) andR02(with predators) that provide threshold conditions on determining the uniform persistence and extinction of the disease in a host population. When the model is absent from predator, the disease is persistent ifR01>1; in such a case, by introducing predators of a vector, then the insect-transmitted disease will be controlled ifR02<1. From the point of biological control, these results show that an additional predator population of the vector may suppress the spread of vector-borne diseases. In addition, there exist limit cycles with persistence of the disease or without disease in presence of predators. Finally, numerical simulations are conducted to support analytical results.

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The Gut Microbiome of the Vector Lutzomyia longipalpis Is Essential for Survival of Leishmania infantum

mBio ◽

10.1128/mbio.01121-16 ◽

2017 ◽

Vol 8 (1) ◽

Cited By ~ 57

Author(s):

Patrick H. Kelly ◽

Sarah M. Bahr ◽

Tiago D. Serafim ◽

Nadim J. Ajami ◽

Joseph F. Petrosino ◽

...

Keyword(s):

Gut Microbiota ◽

Leishmania Infantum ◽

Sand Fly ◽

Lutzomyia Longipalpis ◽

Insect Vector ◽

Sand Flies ◽

Microbial Composition ◽

Vector Borne Diseases ◽

Rdna Sequencing ◽

Vector Borne

ABSTRACT The vector-borne disease leishmaniasis, caused by Leishmania species protozoa, is transmitted to humans by phlebotomine sand flies. Development of Leishmania to infective metacyclic promastigotes in the insect gut, a process termed metacyclogenesis, is an essential prerequisite for transmission. Based on the hypothesis that vector gut microbiota influence the development of virulent parasites, we sequenced midgut microbiomes in the sand fly Lutzomyia longipalpis with or without Leishmania infantum infection. Sucrose-fed sand flies contained a highly diverse, stable midgut microbiome. Blood feeding caused a decrease in microbial richness that eventually recovered. However, bacterial richness progressively decreased in L. infantum-infected sand flies. Acetobacteraceae spp. became dominant and numbers of Pseudomonadaceae spp. diminished coordinately as the parasite underwent metacyclogenesis and parasite numbers increased. Importantly, antibiotic-mediated perturbation of the midgut microbiome rendered sand flies unable to support parasite growth and metacyclogenesis. Together, these data suggest that the sand fly midgut microbiome is a critical factor for Leishmania growth and differentiation to its infective state prior to disease transmission. IMPORTANCE Leishmania infantum, a parasitic protozoan causing fatal visceral leishmaniasis, is transmitted to humans through the bite of the sand fly Lutzomyia longipalpis. Development of the parasite to its virulent metacyclic state occurs in the sand fly gut. In this study, the microbiota within the Lu. longipalpis midgut was delineated by 16S ribosomal DNA (rDNA) sequencing, revealing a highly diverse community composition that lost diversity as parasites developed to their metacyclic state and increased in abundance in infected flies. Perturbing sand fly gut microbiota with an antibiotic cocktail, which alone had no effect on either the parasite or the fly, arrested both the development of virulent parasites and parasite expansion. These findings indicate the importance of bacterial commensals within the insect vector for the development of virulent pathogens, and raise the possibility that impairing the microbial composition within the vector might represent a novel approach to control of vector-borne diseases. IMPORTANCE Leishmania infantum, a parasitic protozoan causing fatal visceral leishmaniasis, is transmitted to humans through the bite of the sand fly Lutzomyia longipalpis. Development of the parasite to its virulent metacyclic state occurs in the sand fly gut. In this study, the microbiota within the Lu. longipalpis midgut was delineated by 16S ribosomal DNA (rDNA) sequencing, revealing a highly diverse community composition that lost diversity as parasites developed to their metacyclic state and increased in abundance in infected flies. Perturbing sand fly gut microbiota with an antibiotic cocktail, which alone had no effect on either the parasite or the fly, arrested both the development of virulent parasites and parasite expansion. These findings indicate the importance of bacterial commensals within the insect vector for the development of virulent pathogens, and raise the possibility that impairing the microbial composition within the vector might represent a novel approach to control of vector-borne diseases.

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Integrated Vector Management: Controlling Vectors of Malaria and Other Insect Vector Borne Diseases. By Graham Matthews. Hoboken (New Jersey): Wiley-Blackwell. $119.95. xi + 234 p.; ill.; index. ISBN: 978-0-4706-5966-3. 2011.

The Quarterly Review of Biology ◽

10.1086/670585 ◽

2013 ◽

Vol 88 (2) ◽

pp. 151-151

Author(s):

Andrew F. Read

Keyword(s):

New Jersey ◽

Insect Vector ◽

Integrated Vector Management ◽

Vector Borne Diseases ◽

Vector Management ◽

Vector Borne

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Biodiversity of Insect Vectors and Parasites: Prospects and Challenges in the 21st Century

Nigeria Journal of Entomology ◽

10.36108/nje/0202/63.01.20 ◽

2020 ◽

Vol 36 (1) ◽

pp. 11-21

Author(s):

Georgina Samuel Mwansat

Keyword(s):

21St Century ◽

Biological Diversity ◽

Ecological Integrity ◽

Insect Vector ◽

Insect Vectors ◽

Vector Borne Diseases ◽

Control Programs ◽

Insect Biodiversity ◽

Vector Borne ◽

The Way

This paper examines diversity of insect vectors and parasites/vector-borne diseases also the successes and challenges in vector control in the 21st century and the way forward suggested. The generally accepted insect biodiversity is estimated to be 5.5 million worldwide with only about 1.5 million described. Generally, four insect orders: Coloeptera, Lepidopera, Hymenoptera and Odonata have been well studied and broadly described. Majority of insect species are known to be beneficial to man and the environment however, insect vectors which are fewer have been identified as causes of morbidity. Mosquitoes which are hematophagous insect vectors are known to be the leading vector for human infectious agents. Insecticides majorly dichloro-diphenyl-trichloroethane (DDT) were therefore used for the control of insect vectors. This succeeded only for a short while in the 19th century due to insect vector resistance and the widely condemned ecological disadvantages. This led to the development of safer and more effective insecticides such as the pyrethriods although also plagued with the tendencies of insect vector resistance. However, it has been strongly indicated that there are links between drivers of global biodiversity modification and vector-borne diseases. This is identified as the strongest reason for control programs that are all encompassing, engaging different fields and institutions, communities and individuals. The Integrated Vector Management (IVM) is therefore, advocated as the way forward for control of insect vector in the 21st century. It is encouraged to be practised putting the basic principles of biodiversity conservation which are ensuring biological diversity, ecological integrity and resilience in proper perspective.

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Corn Stunt Disease: An Ideal Insect–Microbial–Plant Pathosystem for Comprehensive Studies of Vector-Borne Plant Diseases of Corn

Plants ◽

10.3390/plants9060747 ◽

2020 ◽

Vol 9 (6) ◽

pp. 747

Author(s):

Tara-kay L. Jones ◽

Raul F. Medina

Keyword(s):

Pest Control ◽

Plant Diseases ◽

Insect Vector ◽

Ongoing Research ◽

Severe Stunting ◽

Vector Borne Diseases ◽

Spiroplasma Kunkelii ◽

Corn Stunt ◽

Vector Borne ◽

Corn Plants

Over 700 plant diseases identified as vector-borne negatively impact plant health and food security globally. The pest control of vector-borne diseases in agricultural settings is in urgent need of more effective tools. Ongoing research in genetics, molecular biology, physiology, and vector behavior has begun to unravel new insights into the transmission of phytopathogens by their insect vectors. However, the intricate mechanisms involved in phytopathogen transmission for certain pathosystems warrant further investigation. In this review, we propose the corn stunt pathosystem (Zea mays–Spiroplasma kunkelii–Dalbulus maidis) as an ideal model for dissecting the molecular determinants and mechanisms underpinning the persistent transmission of a mollicute by its specialist insect vector to an economically important monocotyledonous crop. Corn stunt is the most important disease of corn in the Americas and the Caribbean, where it causes the severe stunting of corn plants and can result in up to 100% yield loss. A comprehensive study of the corn stunt disease system will pave the way for the discovery of novel molecular targets for genetic pest control targeting either the insect vector or the phytopathogen.

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Urbanization, land tenure security and vector-borne Chagas disease

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2014.1003 ◽

2014 ◽

Vol 281 (1789) ◽

pp. 20141003 ◽

Cited By ~ 33

Author(s):

Michael Z. Levy ◽

Corentin M. Barbu ◽

Ricardo Castillo-Neyra ◽

Victor R. Quispe-Machaca ◽

Jenny Ancca-Juarez ◽

...

Keyword(s):

Chagas Disease ◽

Land Tenure ◽

Construction Materials ◽

Triatoma Infestans ◽

Insect Vector ◽

Tenure Security ◽

Vector Borne Diseases ◽

Modern Cities ◽

Epidemiological Surveys ◽

Vector Borne

Modern cities represent one of the fastest growing ecosystems on the planet. Urbanization occurs in stages; each stage characterized by a distinct habitat that may be more or less susceptible to the establishment of disease vector populations and the transmission of vector-borne pathogens. We performed longitudinal entomological and epidemiological surveys in households along a 1900 × 125 m transect of Arequipa, Peru, a major city of nearly one million inhabitants, in which the transmission of Trypanosoma cruzi , the aetiological agent of Chagas disease, by the insect vector Triatoma infestans , is an ongoing problem. The transect spans a cline of urban development from established communities to land invasions. We find that the vector is tracking the development of the city, and the parasite, in turn, is tracking the dispersal of the vector. New urbanizations are free of vector infestation for decades. T. cruzi transmission is very recent and concentrated in more established communities. The increase in land tenure security during the course of urbanization, if not accompanied by reasonable and enforceable zoning codes, initiates an influx of construction materials, people and animals that creates fertile conditions for epidemics of some vector-borne diseases.

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Blocking the Transmission of a Noncirculative Vector-Borne Plant Pathogenic Bacterium

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-02-16-0032-r ◽

2016 ◽

Vol 29 (7) ◽

pp. 535-544 ◽

Cited By ~ 8

Author(s):

Fabien Labroussaa ◽

Adam R. Zeilinger ◽

Rodrigo P. P. Almeida

Keyword(s):

Cell Adhesion ◽

Plant Pathogens ◽

Control Strategies ◽

Hypothetical Protein ◽

Insect Vector ◽

Bacterial Populations ◽

Vector Borne Diseases ◽

Nontarget Effects ◽

Vector Borne

The successful control of insect-borne plant pathogens is often difficult to achieve due to the ecologically complex interactions among pathogens, vectors, and host plants. Disease management often relies on pesticides and other approaches that have limited long-term sustainability. To add a new tool to control vector-borne diseases, we attempted to block the transmission of a bacterial insect-transmitted pathogen, the bacterium Xylella fastidiosa, by disrupting bacteria–insect vector interactions. X. fastidiosa is known to attach to and colonize the cuticular surface of the mouthparts of vectors; a set of recombinant peptides was generated and the chemical affinities of these peptides to chitin and related carbohydrates was assayed in vitro. Two candidates, the X. fastidiosa hypothetical protein PD1764 and an N-terminal region of the hemagglutinin-like protein B (HxfB) showed affinity for these substrates. These proteins were provided to vectors via an artificial diet system in which insects acquire X. fastidiosa, followed by an inoculation access period on plants under greenhouse conditions. Both PD1764 and HxfAD1-3 significantly blocked transmission. Furthermore, bacterial populations within insects over a 10-day period demonstrated that these peptides inhibited cell adhesion to vectors but not bacterial multiplication, indicating that the mode of action of these peptides is restricted to limiting cell adhesion to insects, likely via competition for adhesion sites. These results open a new venue in the search for sustainable disease-control strategies that are pathogen specific and may have limited nontarget effects.

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