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Viruses Oct 2023Flaviviruses are a family of enveloped viruses with a positive-sense RNA genome, transmitted by arthropod vectors. These viruses are known for their broad cellular... (Review)
Review
Flaviviruses are a family of enveloped viruses with a positive-sense RNA genome, transmitted by arthropod vectors. These viruses are known for their broad cellular tropism leading to infection of multiple body systems, which can include the central nervous system. Neurologic effects of flavivirus infection can arise during both acute and post-acute infectious periods; however, the molecular and cellular mechanisms underlying post-acute sequelae are not fully understood. Here, we review recent studies that have examined molecular and cellular mechanisms that may contribute to neurologic sequelae following infection with the West Nile virus, Japanese encephalitis virus, Zika virus, dengue virus, and St. Louis encephalitis virus. Neuronal death, either from direct infection or due to the resultant inflammatory response, is a common mechanism by which flavivirus infection can lead to neurologic impairment. Other types of cellular damage, such as oxidative stress and DNA damage, appear to be more specific to certain viruses. This article aims to highlight mechanisms of cellular damage that are common across several flavivirus members and mechanisms that are more unique to specific members. Our goal is to inspire further research to improve understanding of this area in the hope of identifying treatment options for flavivirus-associated neurologic changes.
Topics: Animals; Humans; Culicidae; Mosquito Vectors; Flavivirus Infections; Flavivirus; West Nile virus; Zika Virus; Zika Virus Infection
PubMed: 38005878
DOI: 10.3390/v15112200 -
Frontiers in Cellular and Infection... 2023Mosquitoes are responsible for the transmission of numerous viruses of global health significance. The term "vector competence" describes the intrinsic ability of an... (Review)
Review
Mosquitoes are responsible for the transmission of numerous viruses of global health significance. The term "vector competence" describes the intrinsic ability of an arthropod vector to transmit an infectious agent. Prior to transmission, the mosquito itself presents a complex and hostile environment through which a virus must transit to ensure propagation and transmission to the next host. Viruses imbibed in an infectious blood meal must pass in and out of the mosquito midgut, traffic through the body cavity or hemocoel, invade the salivary glands, and be expelled with the saliva when the vector takes a subsequent blood meal. Viruses encounter physical, cellular, microbial, and immunological barriers, which are influenced by the genetic background of the mosquito vector as well as environmental conditions. Collectively, these factors place significant selective pressure on the virus that impact its evolution and transmission. Here, we provide an overview of the current state of the field in understanding the mosquito-specific factors that underpin vector competence and how each of these mechanisms may influence virus evolution.
Topics: Animals; Mosquito Vectors; Arthropod Vectors; Culicidae; Saliva
PubMed: 38188633
DOI: 10.3389/fcimb.2023.1330600 -
Trends in Parasitology May 2022Vector management is a cornerstone in the fight against vector-borne pathogens. However, the impact on ecosystem functioning of reducing or eliminating arthropod vector... (Review)
Review
Vector management is a cornerstone in the fight against vector-borne pathogens. However, the impact on ecosystem functioning of reducing or eliminating arthropod vector populations remains poorly understood. Vectors are members of complex ecological communities, and recent studies suggest that their population suppression alters food web dynamics (bottom-up and top-down trophic cascades), inter- and intraspecific competition, and plant pollination. Other possible overlooked roles are also proposed. In this review, with examples from vectors of plant, animal, and human pathogens, we highlight that, although the ecological roles of most vector species might be redundant with other non-vector species, changes in vector abundance alter biotic interactions and, thus, are unlikely to be neutral in terms of ecosystem functioning.
Topics: Animals; Arthropod Vectors; Biodiversity; Disease Vectors; Ecosystem; Food Chain; Humans; Plants
PubMed: 35421326
DOI: 10.1016/j.pt.2022.01.004 -
Parasites & Vectors Jan 2022Human and animal pathogens that are transmitted by arthropods are a global concern, particularly those vectored by ticks (e.g. Borrelia burgdorferi and tick-borne... (Review)
Review
Human and animal pathogens that are transmitted by arthropods are a global concern, particularly those vectored by ticks (e.g. Borrelia burgdorferi and tick-borne encephalitis virus) and mosquitoes (e.g. malaria and dengue virus). Breaking the circulation of pathogens in permanent foci by controlling vectors using acaricide-based approaches is threatened by the selection of acaricide resistance in vector populations, poor management practices and relaxing of control measures. Alternative strategies that can reduce vector populations and/or vector-mediated transmission are encouraged worldwide. In recent years, it has become clear that arthropod-associated microbiota are involved in many aspects of host physiology and vector competence, prompting research into vector microbiota manipulation. Here, we review how increased knowledge of microbial ecology and vector-host interactions is driving the emergence of new concepts and tools for vector and pathogen control. We focus on the immune functions of host antibodies taken in the blood meal as they can target pathogens and microbiota bacteria within hematophagous arthropods. Anti-microbiota vaccines are presented as a tool to manipulate the vector microbiota and interfere with the development of pathogens within their vectors. Since the importance of some bacterial taxa for colonization of vector-borne pathogens is well known, the disruption of the vector microbiota by host antibodies opens the possibility to develop novel transmission-blocking vaccines.
Topics: Animals; Antibodies; Arthropod Vectors; Disease Transmission, Infectious; Hemolymph; Host-Pathogen Interactions; Humans; Salivary Glands; Vaccine Development
PubMed: 34983601
DOI: 10.1186/s13071-021-05122-5 -
Microbiology Spectrum Sep 2023Many vector-borne pathogens establish multiple-strain infections in the vertebrate host and the arthropod vector. Multiple-strain infections in the host influence strain...
Many vector-borne pathogens establish multiple-strain infections in the vertebrate host and the arthropod vector. Multiple-strain infections in the host influence strain acquisition by naive vectors. Whether multiple-strain infections in the vector influence strain-specific transmission to naive hosts remains unknown. The spirochete, , causes Lyme borreliosis and multiple-strain infections are common in both the tick vector and vertebrate host. Our study used two strains: Fin-Jyv-A3 and NE4049. Donor mice were infected with Fin-Jyv-A3 alone, NE4049 alone, or with both strains. Larval ticks fed on donor mice and molted into nymphal ticks infected with either strain or both strains. These nymphs were fed on test mice to determine whether multiple-strain infections in the nymph influence nymph-to-host transmission (NHT). Multiple-strain infection in the donor mice reduced the acquisition of both strains by ticks by 23%. Thus, a substantial fraction of infected nymphs from the multiple strain treatment were infected with the "wrong" competitor strain rather than the "right" focal strain. As a result, nymphs from the multiple strain treatment were 46% less likely to infect the test mice with the focal strain compared to nymphs from the single strain treatment. However, multiple-strain infection in the nymphal tick had no effect on the NHT of either strain. The nymphal spirochete load of Fin-Jyv-A3 was 1.9 times higher compared to NE4049. NHT of Fin-Jyv-A3 (79%) was 1.5 times higher compared to NE4049 (53%). Our study suggests that strains with higher nymphal spirochete loads have higher NHT. IMPORTANCE For many vector-borne pathogens, multiple-strain infections in the vertebrate host or arthropod vector are common. Multiple-strain infections in the host reduce strain acquisition by feeding vectors. Whether multiple-strain infections in the vector influence strain transmission to the host remains unknown. In our study, we used two strains of the tick-borne spirochete , which causes Lyme borreliosis, to investigate whether multiple-strain infections in the nymphal tick influenced nymph-to-host transmission (NHT) of strains. Multiple-strain infections in mice reduced the acquisition of both strains by nymphal ticks. As a result, nymphs from the multiple strain treatment were less likely to infect naive test mice with the focal strain. Multiple-strain infection in the nymphal ticks did not influence the NHT of either strain. The strain with the higher bacterial abundance in the nymph had higher NHT. Our study suggests that pathogen abundance in the arthropod vector is important for vector-to-host transmission.
PubMed: 37676027
DOI: 10.1128/spectrum.01675-23 -
Viruses Jan 2021Mosquito-borne arthropod-borne viruses (arboviruses) such as the dengue virus (DENV), Zika virus (ZIKV), and chikungunya virus (CHIKV) are important human pathogens that... (Review)
Review
Mosquito-borne arthropod-borne viruses (arboviruses) such as the dengue virus (DENV), Zika virus (ZIKV), and chikungunya virus (CHIKV) are important human pathogens that are responsible for significant global morbidity and mortality. The recent emergence and re-emergence of mosquito-borne viral diseases (MBVDs) highlight the urgent need for safe and effective vaccines, therapeutics, and vector-control approaches to prevent MBVD outbreaks. In nature, arboviruses circulate between vertebrate hosts and arthropod vectors; therefore, disrupting the virus lifecycle in mosquitoes is a major approach for combating MBVDs. Several strategies were proposed to render mosquitoes that are refractory to arboviral infection, for example, those involving the generation of genetically modified mosquitoes or infection with the symbiotic bacterium . Due to the recent development of high-throughput screening methods, an increasing number of drugs with inhibitory effects on mosquito-borne arboviruses in mammalian cells were identified. These antivirals are useful resources that can impede the circulation of arboviruses between arthropods and humans by either rendering viruses more vulnerable in humans or suppressing viral infection by reducing the expression of host factors in mosquitoes. In this review, we summarize recent advances in small-molecule antiarboviral drugs in mammalian and mosquito cells, and discuss how to use these antivirals to block the transmission of MBVDs.
Topics: Aedes; Animals; Antiviral Agents; Arbovirus Infections; Arboviruses; Cells, Cultured; Drug Discovery; Drug Evaluation, Preclinical; Humans; Mosquito Control; Mosquito Vectors; Vector Borne Diseases; Virus Replication
PubMed: 33466915
DOI: 10.3390/v13010108 -
Molecules (Basel, Switzerland) Nov 2020Discovering and validating effective drugs to manage arthropod-borne diseases (ABD) is a timely and important research challenge with major impacts on real-world control...
Discovering and validating effective drugs to manage arthropod-borne diseases (ABD) is a timely and important research challenge with major impacts on real-world control programs at the time of quick resistance development in the targeted pathogens. This editorial highlights major research advances in the development of drugs for the control of vector-borne diseases, with a significant focus on malaria, Chagas disease, dengue, human African trypanosomiasis, leishmaniasis, and Zika. Broad reviews providing new insights on ABD recently published in have also been covered in "The Editors' pick" section.
Topics: Animals; Antimalarials; Antiviral Agents; Arthropod Vectors; Dengue; Drug Development; Humans; Leishmaniasis; Malaria, Falciparum; Trypanocidal Agents; Zika Virus Infection
PubMed: 33172077
DOI: 10.3390/molecules25215175 -
Turkiye Parazitolojii Dergisi Sep 2020Vector-borne zoonotic diseases (VBZDs) are a major problem for public health and animal welfare all over the world. In recent years, there has been an alarming increase... (Review)
Review
Vector-borne zoonotic diseases (VBZDs) are a major problem for public health and animal welfare all over the world. In recent years, there has been an alarming increase in VBZDs, mainly caused by new or re-emerging arboviruses, bacteria and parasites. The World Health Organization enumerated 10 threats to global health for 2019, notably emphasizing climate change and emerging pathogens as growing priorities. It is important to review potential threats and develop new control programs for rising threats against human health and safety. Changes in host and vector population diversity and density may affect pathogen transmission patterns and influence VBZD emergence processes. In addition to environmental and climate-related changes, human and animal migratory patterns pose future threats. The geographic location and habitat features of Turkey support the establishment of many arthropod species as vectors of various diseases. To date, a total of 107 zoonotic infections have been reported originating from Turkey. Arthropods transmit 19 of 107 such infections, including 2 mosquito-borne, 9 tick-borne, 1 sandfly-borne, 3 flea-borne, 1 simuliid-borne, 1 mite-borne and 2 fly-borne diseases. In this review, we focus on the present status of knowledge on VBZDs as a rising threat to public health in Turkey to provide a foundation for future control efforts.
Topics: Animals; Ecosystem; Humans; Mosquito Vectors; Public Health; Turkey; Zoonoses
PubMed: 32928726
DOI: 10.4274/tpd.galenos.2020.6985 -
Nature Reviews. Microbiology Mar 2021Transmission of arthropod-borne viruses (arboviruses) involves infection and replication in both arthropod vectors and vertebrate hosts. Nearly all arboviruses are RNA... (Review)
Review
Transmission of arthropod-borne viruses (arboviruses) involves infection and replication in both arthropod vectors and vertebrate hosts. Nearly all arboviruses are RNA viruses with high mutation frequencies, which leaves them vulnerable to genetic drift and fitness losses owing to population bottlenecks during vector infection, dissemination from the midgut to the salivary glands and transmission to the vertebrate host. However, despite these bottlenecks, they seem to avoid fitness declines that can result from Muller's ratchet. In addition, founder effects that occur during the geographic introductions of human-amplified arboviruses, including chikungunya virus and Zika virus, can affect epidemic and endemic circulation, as well as virulence. In this Review, we discuss the role of genetic drift following population bottlenecks and founder effects in arboviral evolution and spread, and the emergence of human disease.
Topics: Animals; Arbovirus Infections; Arboviruses; Culicidae; Genetic Drift; Genomics; Humans; Vector Borne Diseases
PubMed: 33432235
DOI: 10.1038/s41579-020-00482-8 -
Vaccines Jan 2021Arthropod-borne viruses (Arboviruses) continue to generate significant health and economic burdens for people living in endemic regions. Of these viruses, some of the... (Review)
Review
Arthropod-borne viruses (Arboviruses) continue to generate significant health and economic burdens for people living in endemic regions. Of these viruses, some of the most important (e.g., dengue, Zika, chikungunya, and yellow fever virus), are transmitted mainly by mosquitoes. Over the years, viral infection control has targeted vector population reduction and inhibition of arboviral replication and transmission. This control includes the vector control methods which are classified into chemical, environmental, and biological methods. Some of these control methods may be largely experimental (both field and laboratory investigations) or widely practised. Perceptively, one of the biological methods of vector control, in particular, -based control, shows a promising control strategy for eradicating -borne arboviruses. This can either be through the artificial introduction of , a naturally present bacterium that impedes viral growth in mosquitoes into heterologous mosquito vectors (vectors that are not natural hosts of ) thereby limiting arboviral transmission or via mosquitoes, which naturally harbour infection. These strategies are potentially undermined by the tendency of mosquitoes to lose infection in unfavourable weather conditions (e.g., high temperature) and the inhibitory competitive dynamics among co-circulating strains. The main objective of this review was to critically appraise published articles on vector control strategies and specifically highlight the use of based control to suppress vector population growth or disrupt viral transmission. We retrieved studies on the control strategies for arboviral transmissions via arthropod vectors and discussed the use of control strategies for eradicating arboviral diseases to identify literature gaps that will be instrumental in developing models to estimate the impact of these control strategies and, in essence, the use of different strains and features.
PubMed: 33435566
DOI: 10.3390/vaccines9010032