Host-pathogen interaction in arthropod vectors: Lessons from viral infections

Abstract

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.

Genes, inflammatory response, tolerance, and resistance to virus infections in migratory birds, bats, and rodents

“…In addition to the sustained virome surveillance of bats, rodents and migratory birds, arthropods are another essential source of information for the future control of pandemics ( 132 – 134 ). As in mammals and birds, arthropods also react to potential threatens with an innate immune system response comprising both cellular and humoral components ( 135 ). Arthropods harbor numerous arboviruses that may spread through migratory birds and bats, at stopover sites, to other species, or to other individuals of the same species, and many of these arboviruses are of great epidemiological interest ( 136 , 137 ).…”

“…Arthropods harbor numerous arboviruses that may spread through migratory birds and bats, at stopover sites, to other species, or to other individuals of the same species, and many of these arboviruses are of great epidemiological interest ( 136 , 137 ). For example, mosquito-borne and tick-borne viruses cause some of the most severe diseases with high fatality rates in humans and animals and continue to threat human and livestock health globally ( 135 , 138 , 139 ).…”

Insect-pathogen crosstalk and the cellular-molecular mechanisms of insect immunity: uncovering the underlying signaling pathways and immune regulatory function of non-coding RNAs

“…Viruses may infect insects just like any other kind of organisms (12,177). Some viruses only infect insect cells and are confined to them, whereas other viruses are spread to mammals by insects that bite them (8).Thus, understanding how insect's innate immune systems protect themselves against viruses is of paramount importance from a medical and economic standpoint.…”

“…A variety of B lymphocytes and T lymphocytes are involved in adaptive immunity by recognizing infectious agents (11). Although insects lack an adaptive immune system, their innate immune system is still very effective at recognizing and targeting foreign substances (12).…”

A Comprehensive Review on the Roles of Metals Mediating Insect–Microbial Pathogen Interactions

“…Moreover, the study investigated that metals are pertinent to many physiological processes in insects, plants, and microbial pathogens, including digestion, respiration, and immunity [ 6 ]. However, metals can also limit the growth and virulence of microbial pathogens and act as a defense mechanism for insects against infection [ 7 ]. Understanding the role of metals in the interactions between insects and microbial pathogens can provide insights into the mechanisms of disease transmission and the development of new strategies to control insect pests and microbial pathogens.…”