-
Insects Jan 2021Understanding vertebrate-vector interactions is vitally important for understanding the transmission dynamics of arthropod-vectored pathogens and depends on the ability... (Review)
Review
Understanding vertebrate-vector interactions is vitally important for understanding the transmission dynamics of arthropod-vectored pathogens and depends on the ability to accurately identify the vertebrate source of blood-engorged arthropods in field collections using molecular methods. A decade ago, molecular techniques being applied to arthropod blood meal identification were thoroughly reviewed, but there have been significant advancements in the techniques and technologies available since that time. This review highlights the available diagnostic markers in mitochondrial and nuclear DNA and discusses their benefits and shortcomings for use in molecular identification assays. Advances in real-time PCR, high resolution melting analysis, digital PCR, next generation sequencing, microsphere assays, mass spectrometry, and stable isotope analysis each offer novel approaches and advantages to bloodmeal analysis that have gained traction in the field. New, field-forward technologies and platforms have also come into use that offer promising solutions for point-of-care and remote field deployment for rapid bloodmeal source identification. Some of the lessons learned over the last decade, particularly in the fields of DNA barcoding and sequence analysis, are discussed. Though many advancements have been made, technical challenges remain concerning the prevention of sample degradation both by the arthropod before the sample has been obtained and during storage. This review provides a roadmap and guide for those considering modern techniques for arthropod bloodmeal identification and reviews how advances in molecular technology over the past decade have been applied in this unique biomedical context.
PubMed: 33418885
DOI: 10.3390/insects12010037 -
Pathogens (Basel, Switzerland) Oct 2021Vector behavioural traits, such as fitness, host-seeking, and host-feeding, are key determinants of vectorial capacity, pathogen transmission, and epidemiology of the... (Review)
Review
Vector behavioural traits, such as fitness, host-seeking, and host-feeding, are key determinants of vectorial capacity, pathogen transmission, and epidemiology of the vector-borne disease. Several studies have shown that infection with pathogens can alter these behavioural traits of the arthropod vector. Here, we review relevant publications to assess how pathogens modulate the behaviour of mosquitoes and ticks, major vectors for human diseases. The research has shown that infection with pathogens alter the mosquito's flight activity, mating, fecundity, host-seeking, blood-feeding, and adaptations to insecticide bed nets, and similarly modify the tick's locomotion, questing heights, vertical and horizontal walks, tendency to overcome obstacles, and host-seeking ability. Although some of these behavioural changes may theoretically increase transmission potential of the pathogens, their effect on the disease epidemiology remains to be verified. This study will not only help in understanding virus-vector interactions but will also benefit in establishing role of these behavioural changes in improved epidemiological models and in devising new vector management strategies.
PubMed: 34832532
DOI: 10.3390/pathogens10111376 -
Biology May 2022Vector-borne infectious diseases (e.g., malaria, dengue fever, and yellow fever) result from a parasite transmitted to humans and other animals by blood-feeding... (Review)
Review
Vector-borne infectious diseases (e.g., malaria, dengue fever, and yellow fever) result from a parasite transmitted to humans and other animals by blood-feeding arthropods. They are major contributors to the global disease burden, as they account for nearly a fifth of all infectious diseases worldwide. The interaction between vectors and their hosts plays a key role driving vector-borne disease transmission. Therefore, identifying factors governing host selection by blood-feeding insects is essential to understand the transmission dynamics of vector-borne diseases. Here, we review published information on the physical and chemical stimuli (acoustic, visual, olfactory, moisture and thermal cues) used by mosquitoes and other haemosporidian vectors to detect their vertebrate hosts. We mainly focus on studies on avian malaria and related haemosporidian parasites since this animal model has historically provided important advances in our understanding on ecological and evolutionary process ruling vector-borne disease dynamics and transmission. We also present relevant studies analysing the capacity of feather and skin symbiotic bacteria in the production of volatile compounds with vector attractant properties. Furthermore, we review the role of uropygial secretions and symbiotic bacteria in bird-insect vector interactions. In addition, we present investigations examining the alterations induced by haemosporidian parasites on their arthropod vector and vertebrate host to enhance parasite transmission. Finally, we propose future lines of research for designing successful vector control strategies and for infectious disease management.
PubMed: 35625454
DOI: 10.3390/biology11050726 -
Frontiers in Immunology 2023Haematophagous arthropods can harbor various pathogens including viruses, bacteria, protozoa, and nematodes. Insects possess an innate immune system comprising of both... (Review)
Review
Haematophagous arthropods can harbor various pathogens including viruses, bacteria, protozoa, and nematodes. Insects possess an innate immune system comprising of both cellular and humoral components to fight against various infections. Haemocytes, the cellular components of haemolymph, are central to the insect immune system as their primary functions include phagocytosis, encapsulation, coagulation, detoxification, and storage and distribution of nutritive materials. Plasmatocytes and granulocytes are also involved in cellular defense responses. Blood-feeding arthropods, such as mosquitoes and ticks, can harbour a variety of viral pathogens that can cause infectious diseases in both human and animal hosts. Therefore, it is imperative to study the virus-vector-host relationships since arthropod vectors are important constituents of the ecosystem. Regardless of the complex immune response of these arthropod vectors, the viruses usually manage to survive and are transmitted to the eventual host. A multidisciplinary approach utilizing novel and strategic interventions is required to control ectoparasite infestations and block vector-borne transmission of viral pathogens to humans and animals. In this review, we discuss the arthropod immune response to viral infections with a primary focus on the innate immune responses of ticks and mosquitoes. We aim to summarize critically the vector immune system and their infection transmission strategies to mammalian hosts to foster debate that could help in developing new therapeutic strategies to protect human and animal hosts against arthropod-borne viral infections.
Topics: Animals; Humans; Ecosystem; Mosquito Vectors; Arthropod Vectors; Arthropods; Host-Pathogen Interactions; Ticks; Culicidae; Virus Diseases; Mammals
PubMed: 36817439
DOI: 10.3389/fimmu.2023.1061899 -
Journal of Infection in Developing... Feb 2023Bluetongue (BT), once considered a disease of sheep confined to the southern African region, has spread all over the world. BT is a viral disease caused by the... (Review)
Review
Bluetongue (BT), once considered a disease of sheep confined to the southern African region, has spread all over the world. BT is a viral disease caused by the bluetongue virus (BTV). BT is regarded as an economically important disease in ruminants of compulsory notification to OIE. BTV is transmitted by the bite of Culicoides species. Research over the years has led to a better understanding of the disease, the nature of the virus life cycle between ruminants and Culicoides species, and its distribution in different geographical regions. Advances have also been made in understanding the molecular structure and function of the virus, the biology of the Culicoides species, its ability to transmit the disease, and the persistence of the virus inside the Culicoides and the mammalian hosts. Global climate change has enabled the colonization of new habitats and the spread of the virus into additional species of the Culicoides vector. This review highlights some of the current findings on the status of BT in the world based on the latest research on disease aspects, virus-host-vector interactions, and the different diagnostic approaches and control strategies available for BTV.
Topics: Animals; Sheep; Bluetongue virus; Insect Vectors; Ruminants; Bluetongue; Ceratopogonidae
PubMed: 36897898
DOI: 10.3855/jidc.16947 -
The American Journal of Tropical... Feb 2023Aedes (Stegomyia) albopictus (Skuse) (Diptera: Culicidae) transmits a variety of arboviruses (arthropod-borne viruses) and acts as one of the most dangerous mosquito... (Review)
Review
Aedes (Stegomyia) albopictus (Skuse) (Diptera: Culicidae) transmits a variety of arboviruses (arthropod-borne viruses) and acts as one of the most dangerous mosquito species in the world. Mosquito surveillance is the main means of evaluating vector density, vector-borne disease risk, and the efficacy of vector-control operations. The larval density of Ae. albopictus can be reflected by means of Breteau index and Route index, and egg density can be monitored by ovitrap and mosq-ovitrap, whereas mosquito surveillance methods mainly include human landing catch, human-baited double net trap, BG-Sentinel trap, autocidal gravid ovitrap, gravid Aedes trap, and mosquito magnet. This article describes different methods of Ae. albopictus surveillance and offers suggestions to improve surveillance.
Topics: Animals; Humans; Aedes; Mosquito Vectors; Arboviruses; Mosquito Control
PubMed: 36315996
DOI: 10.4269/ajtmh.20-0781 -
Biomolecules Jul 2023Arthropod-borne viruses (arboviruses) pose a significant threat to both human and animal health worldwide. These viruses are transmitted through the bites of mosquitoes,... (Review)
Review
Arthropod-borne viruses (arboviruses) pose a significant threat to both human and animal health worldwide. These viruses are transmitted through the bites of mosquitoes, ticks, sandflies, or biting midges to humans or animals. In humans, arbovirus infection often results in mild flu-like symptoms, but severe disease and death also occur. There are few vaccines available, so control efforts focus on the mosquito population and virus transmission control. One area of research that may enable the development of new strategies to control arbovirus transmission is the field of vector immunology. Arthropod vectors, such as mosquitoes, have coevolved with arboviruses, resulting in a balance of virus replication and vector immune responses. If this balance were disrupted, virus transmission would likely be reduced, either through reduced replication, or even through enhanced replication, resulting in mosquito mortality. The first step in mounting any immune response is to recognize the presence of an invading pathogen. Recent research advances have been made to tease apart the mechanisms of arbovirus detection by mosquitoes. Here, we summarize what is known about arbovirus recognition by the mosquito immune system, try to generate a comprehensive picture, and highlight where there are still gaps in our current understanding.
Topics: Animals; Humans; Arboviruses; Culicidae; Mosquito Vectors; Arbovirus Infections; Immune System
PubMed: 37509194
DOI: 10.3390/biom13071159 -
Science (New York, N.Y.) Jan 2023Ancestral signaling pathways serve critical roles in metazoan development, physiology, and immunity. We report an evolutionary interspecies communication pathway...
Ancestral signaling pathways serve critical roles in metazoan development, physiology, and immunity. We report an evolutionary interspecies communication pathway involving a central tick receptor termed Dome1, which acquired a mammalian cytokine receptor motif exhibiting high affinity for interferon-gamma (IFN-γ). Host-derived IFN-γ facilitates Dome1-mediated activation of the JAK-STAT pathway. This accelerates tick blood meal acquisition and development while upregulating antimicrobial components. The Dome1-JAK-STAT pathway, which exists in most Ixodid tick genomes, regulates the regeneration and proliferation of gut cells-including stem cells-and dictates metamorphosis through the Hedgehog and Notch-Delta networks, ultimately affecting vectorial competence. We highlight the evolutionary dependence of on mammalian hosts through cross-species signaling mechanisms that dually influence arthropod immunity and development.
Topics: Animals; Interferon-gamma; Ixodes; Janus Kinases; Signal Transduction; STAT Transcription Factors; Host-Parasite Interactions; Receptors, Cytokine; Arachnid Vectors
PubMed: 36634189
DOI: 10.1126/science.abl3837 -
Plants (Basel, Switzerland) Dec 2020Epidemiology is the science of how disease develops in populations, with applications in human, animal and plant diseases. For plant diseases, epidemiology has developed... (Review)
Review
Epidemiology is the science of how disease develops in populations, with applications in human, animal and plant diseases. For plant diseases, epidemiology has developed as a quantitative science with the aims of describing, understanding and predicting epidemics, and intervening to mitigate their consequences in plant populations. Although the central focus of epidemiology is at the population level, it is often necessary to recognise the system hierarchies present by scaling down to the individual plant/cellular level and scaling up to the community/landscape level. This is particularly important for diseases caused by plant viruses, which in most cases are transmitted by arthropod vectors. This leads to range of virus-plant, virus-vector and vector-plant interactions giving a distinctive character to plant virus epidemiology (whilst recognising that some fungal, oomycete and bacterial pathogens are also vector-borne). These interactions have epidemiological, ecological and evolutionary consequences with implications for agronomic practices, pest and disease management, host resistance deployment, and the health of wild plant communities. Over the last two decades, there have been attempts to bring together these differing standpoints into a new synthesis, although this is more apparent for evolutionary and ecological approaches, perhaps reflecting the greater emphasis on shorter often annual time scales in epidemiological studies. It is argued here that incorporating an epidemiological perspective, specifically quantitative, into this developing synthesis will lead to new directions in plant virus research and disease management. This synthesis can serve to further consolidate and transform epidemiology as a key element in plant virus research.
PubMed: 33327457
DOI: 10.3390/plants9121768 -
Journal of Cell Science Nov 2020Non-coding RNAs (ncRNAs) are nucleotide sequences that are known to assume regulatory roles previously thought to be reserved for proteins. Their functions include the... (Review)
Review
Non-coding RNAs (ncRNAs) are nucleotide sequences that are known to assume regulatory roles previously thought to be reserved for proteins. Their functions include the regulation of protein activity and localization and the organization of subcellular structures. Sequencing studies have now identified thousands of ncRNAs encoded within the prokaryotic and eukaryotic genomes, leading to advances in several fields including parasitology. ncRNAs play major roles in several aspects of vector-host-pathogen interactions. Arthropod vector ncRNAs are secreted through extracellular vesicles into vertebrate hosts to counteract host defense systems and ensure arthropod survival. Conversely, hosts can use specific ncRNAs as one of several strategies to overcome arthropod vector invasion. In addition, pathogens transmitted through vector saliva into vertebrate hosts also possess ncRNAs thought to contribute to their pathogenicity. Recent studies have addressed ncRNAs in vectors or vertebrate hosts, with relatively few studies investigating the role of ncRNAs derived from pathogens and their involvement in establishing infections, especially in the context of vector-borne diseases. This Review summarizes recent data focusing on pathogen-derived ncRNAs and their role in modulating the cellular responses that favor pathogen survival in the vertebrate host and the arthropod vector, as well as host ncRNAs that interact with vector-borne pathogens.
Topics: Animals; Arthropod Vectors; Disease Vectors; Eukaryotic Cells; Host-Pathogen Interactions; RNA, Untranslated
PubMed: 33154170
DOI: 10.1242/jcs.246744