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ELife Oct 2020Vector-borne illnesses comprise a significant portion of human maladies, representing 17% of global infections. Transmission of vector-borne pathogens to mammals... (Review)
Review
Vector-borne illnesses comprise a significant portion of human maladies, representing 17% of global infections. Transmission of vector-borne pathogens to mammals primarily occurs by hematophagous arthropods. It is speculated that blood may provide a unique environment that aids in the replication and pathogenesis of these microbes. Lipids and their derivatives are one component enriched in blood and are essential for microbial survival. For instance, the malarial parasite and the Lyme disease spirochete , among others, have been shown to scavenge and manipulate host lipids for structural support, metabolism, replication, immune evasion, and disease severity. In this , we will explore the importance of lipid hijacking for the growth and persistence of these microbes in both mammalian hosts and arthropod vectors.
Topics: Animals; Borrelia; Culicidae; Humans; Insecta; Lipid Metabolism; Ticks; Trypanosomatina; Vector Borne Diseases
PubMed: 33118933
DOI: 10.7554/eLife.61675 -
Frontiers in Cellular and Infection... 2022
Topics: Animals; Arthropod Vectors; Arthropods; Feeding Behavior; Insect Vectors; Saliva
PubMed: 35909959
DOI: 10.3389/fcimb.2022.977511 -
Frontiers in Cellular and Infection... 2020
Topics: Animals; Arthropod Vectors; Arthropods; Saliva; Ticks
PubMed: 33585290
DOI: 10.3389/fcimb.2020.630626 -
Microorganisms Aug 2022Yellow fever virus (YFV) is a mosquito-borne flavivirus circulating throughout the tropical and sub-tropical regions of Africa and South America. It is responsible for... (Review)
Review
Yellow fever virus (YFV) is a mosquito-borne flavivirus circulating throughout the tropical and sub-tropical regions of Africa and South America. It is responsible for an estimated 30,000 deaths annually, and while there is a highly successful vaccine, coverage is incomplete, and there is no approved treatment for YFV infection. Despite advancements in the field, animal models for YFV infection remain scarce, and care must be taken to select an appropriate model for a given hypothesis. Small animal models require either adapted YFV strains or immunocompromised hosts. Non-human primates (NHPs) recapitulate human disease, but they require specialized facilities and training, are often in short supply and cost-prohibitive, and can present ethical concerns. The limitations in studying the mosquito vectors for YFV infection include inconsistency in the laboratory environment, the requirement for a high containment insectary, and difficulty in maintaining sylvatic mosquitoes. In this review, we discuss the roles of animal models and arthropod vector studies in understanding epidemic emergence.
PubMed: 36013996
DOI: 10.3390/microorganisms10081578 -
The Journal of General Virology Jan 2020Peribunyaviruses are enveloped and possess three distinct, single-stranded, negative-sense RNA segments comprising 11.2-12.5 kb in total. The family includes globally...
Peribunyaviruses are enveloped and possess three distinct, single-stranded, negative-sense RNA segments comprising 11.2-12.5 kb in total. The family includes globally distributed viruses in the genera , , and . Most viruses are maintained in geographically-restricted vertebrate-arthropod transmission cycles that can include transovarial transmission from arthropod dam to offspring. Others are arthropod-specific. Arthropods can be persistently infected. Human infection occurs through blood feeding by an infected vector arthropod. Infections can result in a diversity of human and veterinary clinical outcomes in a strain-specific manner. Segment reassortment is evident between some peribunyaviruses. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the family , which is available at ictv.global/report/peribunyaviridae.
Topics: Animals; Arthropod Vectors; Arthropods; Genome, Viral; Humans; Phylogeny; RNA Viruses; Virion
PubMed: 31846417
DOI: 10.1099/jgv.0.001365 -
Parasites & Vectors Jan 2023The availability of molecular techniques has significantly increased our understanding of bacteria of the order Rickettsiales, allowing the identification of distinct... (Review)
Review
BACKGROUND
The availability of molecular techniques has significantly increased our understanding of bacteria of the order Rickettsiales, allowing the identification of distinct species in both vector and host arthropods. However, the literature lacks studies that comprehensively summarize the vast amount of knowledge generated on this topic in recent years. The purpose of this study was to conduct a comprehensive analysis of the distribution of Rickettsiales in arthropod vectors, animals and humans in the WHO European Region in order to provide useful information to predict the emergence of certain diseases in specific geographical areas and to formulate hypotheses regarding the possible pathogenetic role of some rickettsial species in the etiology of human pathological conditions.
METHODS
A systematic review of the literature in the PubMed and EMBASE databases was conducted following the PRISMA methodology using the search terms "Spotted fever" OR "rickettsiosis" OR "ricketts*" AND all the countries of the WHO European Region, from 1 January 2013 to 12 February 2022. Only studies that identified rickettsiae in human, animal or arthropod samples using molecular techniques were included in the review.
RESULTS
A total of 467 articles considering 61 different species of Rickettsiales with confirmed or suspected human pathogenicity were analyzed in the review. More than 566 identifications of Rickettsiales DNA in human samples were described, of which 89 cases were assessed as importation cases. A total of 55 species of ticks, 17 species of fleas, 10 species of mite and four species of lice were found infected. Twenty-three species of Rickettsiales were detected in wild and domestic animal samples.
CONCLUSION
The routine use of molecular methods to search for Rickettsiales DNA in questing ticks and other blood-sucking arthropods that commonly bite humans should be encouraged. Molecular methods specific for Rickettsiales should be used routinely in the diagnostics of fever of unknown origin and in all cases of human diseases secondary to an arthropod bite or animal contact.
Topics: Animals; Humans; One Health; Rickettsia; Rickettsia Infections; Rickettsiales; Ticks; World Health Organization
PubMed: 36717936
DOI: 10.1186/s13071-022-05646-4 -
Cell Reports Aug 2023Arthropod-borne viruses (arboviruses) transmitted by Aedes aegypti mosquitoes are an increasing threat to global health. The small interfering RNA (siRNA) pathway is...
Arthropod-borne viruses (arboviruses) transmitted by Aedes aegypti mosquitoes are an increasing threat to global health. The small interfering RNA (siRNA) pathway is considered the main antiviral immune pathway of insects, but its effective impact on arbovirus transmission is surprisingly poorly understood. Here, we use CRISPR-Cas9-mediated gene editing in vivo to mutate Dicer2, a gene encoding the RNA sensor and key component of the siRNA pathway. The loss of Dicer2 enhances early viral replication and systemic viral dissemination of four medically significant arboviruses (chikungunya, Mayaro, dengue, and Zika viruses) representing two viral families. However, Dicer2 mutants and wild-type mosquitoes display overall similar levels of vector competence. In addition, Dicer2 mutants undergo significant virus-induced mortality during infection with chikungunya virus. Together, our results define a multifaceted role for Dicer2 in the transmission of arboviruses by Ae. aegypti mosquitoes and pave the way for further mechanistic investigations.
Topics: Animals; Humans; Arboviruses; Aedes; Mosquito Vectors; Zika Virus; RNA, Small Interfering; Zika Virus Infection
PubMed: 37573505
DOI: 10.1016/j.celrep.2023.112977 -
Modern Pathology : An Official Journal... Jun 2023Flaviviruses are a genus of single-stranded RNA viruses that impose an important and growing burden to human health. There are over 3 billion individuals living in areas... (Review)
Review
Flaviviruses are a genus of single-stranded RNA viruses that impose an important and growing burden to human health. There are over 3 billion individuals living in areas where flaviviruses are endemic. Flaviviruses and their arthropod vectors (which include mosquitoes and ticks) take advantage of global travel to expand their distribution and cause severe disease in humans, and they can be grouped according to their vector and pathogenicity. The mosquito-borne flaviviruses cause a spectrum of diseases from encephalitis to hepatitis and vascular shock syndrome, congenital abnormalities, and fetal death. Neurotropic infections such as Zika virus and West Nile virus cross the blood-brain barrier and infect neurons and other cells, leading to meningoencephalitis. In the hemorrhagic fever clade, there are yellow fever virus, the prototypical hemorrhagic fever virus that infects hepatocytes, and dengue virus, which infects cells of the reticuloendothelial system and can lead to a dramatic plasma cell leakage and shock syndrome. Zika virus also causes congenital infections and fetal death and is the first and only example of a teratogenic arbovirus in humans. Diagnostic testing for flaviviruses broadly includes the detection of viral RNA in serum (particularly within the first 10 days of symptoms), viral isolation by cell culture (rarely performed due to complexity and biosafety concerns), and histopathologic evaluation with immunohistochemistry and molecular testing on formalin-fixed paraffin-embedded tissue blocks. This review focuses on 4 mosquito-borne flaviviruses-West Nile, yellow fever, dengue, and Zika virus-and discusses the mechanisms of transmission, the role of travel in geographic distribution and epidemic emergence, and the clinical and histopathologic features of each. Finally, prevention strategies such as vector control and vaccination are discussed.
Topics: Animals; Humans; Flavivirus; Zika Virus; Pathologists; West Nile Fever; Mosquito Vectors; Yellow Fever; Culicidae; Dengue; Zika Virus Infection
PubMed: 37059228
DOI: 10.1016/j.modpat.2023.100188 -
MSphere Dec 2022Ngari virus (NRIV) is a mosquito-borne reassortant orthobunyavirus that causes severe febrile illness and hemorrhagic fever in humans and small ruminants. Due to limited...
Ngari virus (NRIV) is a mosquito-borne reassortant orthobunyavirus that causes severe febrile illness and hemorrhagic fever in humans and small ruminants. Due to limited diagnostics and surveillance, NRIV has only been detected sporadically during Rift Valley fever virus outbreaks. Little is known on its interepidemic maintenance and geographic distribution. In this study, sera from cattle, goats, and sheep were collected through a cross-sectional survey after the rainy seasons between 2020 and 2021 in two pastoralist-dominated semiarid ecosystems, Baringo and Kajiado counties in Kenya. NRIV was detected in 11 apparently healthy animals (11/2,039, 0.54%) by RT-PCR and isolated in cell culture from seven individuals. Growth analyses displayed efficient replication in cells from sheep and humans in contrast to weak replication in goat cells. NRIV infection of a wide variety of different vector cells showed only rapid replication in Aedes albopictus cells but not in cells derived from other mosquito species or sandflies. Phylogenetic analyses of complete-coding sequences of L, M, and S segments of four viruses showed that the Kenyan sequences established a monophyletic clade most closely related to a NRIV sequence from a small ruminant from Mauritania. NRIV neutralizing reactivity in cattle, goats, and sheep were 41.6% (95% CI = 30 to 54.3), 52.4% (95% CI = 37.7 to 66.6), and 19% (95% CI = 9.7 to 33.6), respectively. This is the first detection of NRIV in livestock in Kenya. Our results demonstrate active and undetected circulation of NRIV in the three most common livestock species highlighting the need for an active one-health surveillance of host networks, including humans, livestock, and vectors. Surveillance of vectors and hosts for infection with zoonotic arthropod-borne viruses is important for early detection and intervention measures to prevent outbreaks. Here, we report the undetected circulation of Ngari virus (NRIV) in apparently healthy cattle, sheep, and goats in Kenya. NRIV is associated with outbreaks of hemorrhagic fever in humans and small ruminants. We demonstrate the isolation of infectious virus from several animals as well as presence of neutralizing antibodies in 38% of the tested animals. Our data indicate active virus circulation and endemicity likely having important implications for human and animal health.
Topics: Animals; Cattle; Humans; Sheep; Kenya; Rift Valley Fever; Livestock; Cross-Sectional Studies; Phylogeny; Ecosystem; Mosquito Vectors; Rift Valley fever virus; Ruminants; Goats; Aedes
PubMed: 36472449
DOI: 10.1128/msphere.00416-22 -
Frontiers in Immunology 2020Understanding what influences the ability of some arthropods to harbor and transmit pathogens may be key for controlling the spread of vector-borne diseases. Arthropod... (Review)
Review
Understanding what influences the ability of some arthropods to harbor and transmit pathogens may be key for controlling the spread of vector-borne diseases. Arthropod immunity has a central role in dictating vector competence for pathogen acquisition and transmission. Microbial infection elicits immune responses and imparts stress on the host by causing physical damage and nutrient deprivation, which triggers evolutionarily conserved stress response pathways aimed at restoring cellular homeostasis. Recent studies increasingly recognize that eukaryotic stress responses and innate immunity are closely intertwined. Herein, we describe two well-characterized and evolutionarily conserved mechanisms, the Unfolded Protein Response (UPR) and the Integrated Stress Response (ISR), and examine evidence that these stress responses impact immune signaling. We then describe how multiple pathogens, including vector-borne microbes, interface with stress responses in mammals. Owing to the well-conserved nature of the UPR and ISR, we speculate that similar mechanisms may be occurring in arthropod vectors and ultimately impacting vector competence. We conclude this Perspective by positing that novel insights into vector competence will emerge when considering that stress-signaling pathways may be influencing the arthropod immune network.
Topics: Animals; Arthropod Vectors; Host-Pathogen Interactions; Humans; Immunity, Innate; Signal Transduction; Unfolded Protein Response
PubMed: 33659000
DOI: 10.3389/fimmu.2020.629777