scholarly journals Vector Competence of Eucampsipoda africana (Diptera: Nycteribiidae) for Marburg Virus Transmission in Rousettus aegyptiacus (Chiroptera: Pteropodidae)

Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2226
Author(s):  
Janusz T. Pawęska ◽  
Petrus Jansen van Vuren ◽  
Nadia Storm ◽  
Wanda Markotter ◽  
Alan Kemp
Keyword(s):  
Vector Competence ◽  
Virus Transmission ◽  
Marburg Virus ◽  
Mechanical Transmission ◽  
Virus Concentration ◽  
Post Inoculation ◽  
Rt Pcr ◽  
Bat Flies ◽  
Filial Generation ◽  
Contaminated Blood

This study aimed to determine the vector competence of bat-associated nycteribiid flies (Eucamsipoda africana) for Marburg virus (MARV) in the Egyptian Rousette Bat (ERB), Rousettus aegyptiacus. In flies fed on subcutaneously infected ERBs and tested from 3 to 43 days post infection (dpi), MARV was detected only in those that took blood during the peak of viremia, 5–7 dpi. Seroconversion did not occur in control bats in contact with MARV-infected bats infested with bat flies up to 43 days post exposure. In flies inoculated intra-coelomically with MARV and tested on days 0–29 post inoculation, only those assayed on day 0 and day 7 after inoculation were positive by q-RT-PCR, but the virus concentration was consistent with that of the inoculum. Bats remained MARV-seronegative up to 38 days after infestation and exposure to inoculated flies. The first filial generation pupae and flies collected at different times during the experiments were all negative by q-RT-PCR. Of 1693 nycteribiid flies collected from a wild ERB colony in Mahune Cave, South Africa where the enzootic transmission of MARV occurs, only one (0.06%) tested positive for the presence of MARV RNA. Our findings seem to demonstrate that bat flies do not play a significant role in the transmission and enzootic maintenance of MARV. However, ERBs eat nycteribiid flies; thus, the mechanical transmission of the virus through the exposure of damaged mucous membranes and/or skin to flies engorged with contaminated blood cannot be ruled out.

scholarly journals Putative Role of Arthropod Vectors in African Swine Fever Virus Transmission in Relation to Their Bio-Ecological Properties

Viruses ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 778 ◽  
Author(s):  
Sarah I. Bonnet ◽  
Emilie Bouhsira ◽  
Nick De Regge ◽  
Johanna Fite ◽  
Florence Etoré ◽  
...  
Keyword(s):  
African Swine Fever Virus ◽  
Vector Competence ◽  
Virus Transmission ◽  
African Swine Fever ◽  
Mechanical Transmission ◽  
Vector Ecology ◽  
Trade Restrictions ◽  
Indirect Transmission ◽  
Baltic Countries ◽  
Management Measures

African swine fever (ASF) is one of the most important diseases in Suidae due to its significant health and socioeconomic consequences and represents a major threat to the European pig industry, especially in the absence of any available treatment or vaccine. In fact, with its high mortality rate and the subsequent trade restrictions imposed on affected countries, ASF can dramatically disrupt the pig industry in afflicted countries. In September 2018, ASF was unexpectedly identified in wild boars from southern Belgium in the province of Luxembourg, not far from the Franco-Belgian border. The French authorities rapidly commissioned an expert opinion on the risk of ASF introduction and dissemination into metropolitan France. In Europe, the main transmission routes of the virus comprise direct contact between infected and susceptible animals and indirect transmission through contaminated material or feed. However, the seasonality of the disease in some pig farms in Baltic countries, including outbreaks in farms with high biosecurity levels, have led to questions on the possible involvement of arthropods in the transmission of the virus. This review explores the current body of knowledge on the most common arthropod families present in metropolitan France. We examine their potential role in spreading ASF—by active biological or mechanical transmission or by passive transport or ingestion—in relation to their bio-ecological properties. It also highlights the existence of significant gaps in our knowledge on vector ecology in domestic and wild boar environments and in vector competence for ASFV transmission. Filling these gaps is essential to further understanding ASF transmission in order to thus implement appropriate management measures.

scholarly journals In Vitro Rearing of Perkinsiella saccharicida and the Use of Leaf Segments to Assay Fiji disease virus Transmission

2008 ◽  
Vol 98 (7) ◽  
pp. 810-814 ◽  
Author(s):  
G. L. Hughes ◽  
P. G. Allsopp ◽  
S. M. Brumbley ◽  
K. N. Johnson ◽  
S. L. O'Neill
Keyword(s):  
Disease Virus ◽  
Vector Competence ◽  
Virus Transmission ◽  
Subsequent Development ◽  
Leaf Segment ◽  
Rt Pcr ◽  
Additional Measure ◽  
Fiji Disease Virus ◽  
Leaf Segments

Fiji leaf gall (FLG) is caused by the Reovirus, Fiji disease virus (FDV), which is transmitted to sugarcane by planthoppers of the genus Perkinsiella. Low vector transmission rates and slow disease symptom development make experimentation within the FDV-Perkinsiella-sugarcane system inherently difficult. A laboratory-based technique was devised to rear the vector using sugarcane leaves as a food source. Planthoppers were reared on sugarcane leaf segments embedded in agarose enclosed within plastic containers. To provide a nondestructive assay for determination of the inoculation potential of planthoppers, FDV was detected by reverse transcription-polymerase chain reaction (RT-PCR) in newly infected sugarcane leaf segments following exposure to viruliferous planthoppers. Leaf segment inoculation correlated with development of FLG symptoms in whole plants that were fed on by the same planthoppers. Analysis of FDV RNAs within the planthopper, measured by quantitative RT-PCR (qRT-PCR), indicated that FDV RNA concentration was associated with successful inoculation of the leaf segment, transmission of FDV to sugarcane and subsequent development of FLG in plants. Quantification of FDV RNA within planthoppers provided an additional measure to assess vector competence in individuals.

scholarly journals Combination therapy protects macaques against advanced Marburg virus disease

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Robert W. Cross ◽  
Zachary A. Bornholdt ◽  
Abhishek N. Prasad ◽  
Viktoriya Borisevich ◽  
Krystle N. Agans ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Rhesus Monkeys ◽  
Viral Infections ◽  
Virus Disease ◽  
Marburg Virus ◽  
Therapeutic Window ◽  
Post Inoculation ◽  
Primate Model ◽  
Lethal Infection ◽  
Human Primate

AbstractMonoclonal antibodies (mAbs) and remdesivir, a small-molecule antiviral, are promising monotherapies for many viruses, including members of the genera Marburgvirus and Ebolavirus (family Filoviridae), and more recently, SARS-CoV-2. One of the major challenges of acute viral infections is the treatment of advanced disease. Thus, extending the window of therapeutic intervention is critical. Here, we explore the benefit of combination therapy with a mAb and remdesivir in a non-human primate model of Marburg virus (MARV) disease. While rhesus monkeys are protected against lethal infection when treatment with either a human mAb (MR186-YTE; 100%), or remdesivir (80%), is initiated 5 days post-inoculation (dpi) with MARV, no animals survive when either treatment is initiated alone beginning 6 dpi. However, by combining MR186-YTE with remdesivir beginning 6 dpi, significant protection (80%) is achieved, thereby extending the therapeutic window. These results suggest value in exploring combination therapy in patients presenting with advanced filovirus disease.

scholarly journals Sequential Infection of Aedes aegypti Mosquitoes with Chikungunya Virus and Zika Virus Enhances Early Zika Virus Transmission

Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 177 ◽  
Author(s):  
Tereza Magalhaes ◽  
Alexis Robison ◽  
Michael Young ◽  
William Black ◽  
Brian Foy ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Blood Meal ◽  
Zika Virus ◽  
Chikungunya Virus ◽  
Vector Competence ◽  
Virus Transmission ◽  
Mosquito Vector ◽  
Molecular Aspects ◽  
Virus Interactions ◽  
Sequential Infection

In urban settings, chikungunya, Zika, and dengue viruses are transmitted by Aedes aegypti mosquitoes. Since these viruses co-circulate in several regions, coinfection in humans and vectors may occur, and human coinfections have been frequently reported. Yet, little is known about the molecular aspects of virus interactions within hosts and how they contribute to arbovirus transmission dynamics. We have previously shown that Aedes aegypti exposed to chikungunya and Zika viruses in the same blood meal can become coinfected and transmit both viruses simultaneously. However, mosquitoes may also become coinfected by multiple, sequential feeds on single infected hosts. Therefore, we tested whether sequential infection with chikungunya and Zika viruses impacts mosquito vector competence. We exposed Ae. aegypti mosquitoes first to one virus and 7 days later to the other virus and compared infection, dissemination, and transmission rates between sequentially and single infected groups. We found that coinfection rates were high after sequential exposure and that mosquitoes were able to co-transmit both viruses. Surprisingly, chikungunya virus coinfection enhanced Zika virus transmission 7 days after the second blood meal. Our data demonstrate heterologous arbovirus synergism within mosquitoes, by unknown mechanisms, leading to enhancement of transmission under certain conditions.

Susceptibility of the Mongolian gerbil (Meriones unguiculatus) to Western equine encephalitis

1972 ◽  
Vol 18 (6) ◽  
pp. 941-944 ◽  
Author(s):  
L. B. Hayles
Keyword(s):  
Mongolian Gerbil ◽  
Standard Dose ◽  
Clinical Signs ◽  
Meriones Unguiculatus ◽  
Virus Concentration ◽  
Post Inoculation ◽  
Equine Encephalitis Virus ◽  
Western Equine Encephalitis Virus ◽  
Peripheral Infection ◽  
Western Equine Encephalitis

The Mongolian gerbil (Meriones unguiculatus) was highly susceptible to peripheral infection with Western equine encephalitis virus. Small doses of virus ranging from 0.1 to 10 intracerebral 3-week-old mouse LD50 which induced no clinical response in 3-week-old mice when inoculated subcutaneously, caused death in 4-week-old gerbils. At this age, a standard dose of virus produced uniform viremia patterns between individuals. Peak virus concentration approaching 105.0 intracerebral 3-week-old mouse LD50 per 0.03 milliliter of blood, was attained at 48 h post inoculation. Resistance to infection increased with age but 10-week old gerbils remained susceptible and exhibited marked clinical signs of encephalitis during the course of infection. Brains from animals, which died within 10 days of infection, yielded large amounts of virus.

scholarly journals Transstadial Transmission and Replication Kinetics of West Nile Virus Lineage 1 in Laboratory Reared Ixodes ricinus Ticks

Pathogens ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 780
Author(s):  
Cristian Răileanu ◽  
Oliver Tauchmann ◽  
Ana Vasić ◽  
Ulrike Neumann ◽  
Birke Andrea Tews ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Ixodes Ricinus ◽  
Tick Species ◽  
Vector Competence ◽  
Virus Transmission ◽  
Viral Agent ◽  
West Nile ◽  
Transstadial Transmission ◽  
Kinetics Of

West Nile virus (WNV) is a mosquito-borne agent that has also been isolated from several tick species. Vector competence of Ixodes ricinus, one of the most common tick species in Europe, has been poorly investigated for WNV to date. As such, to evaluate the vector competence, laboratory reared Ixodes ricinus nymphs were in vitro fed with WNV lineage 1 infectious blood, allowed to molt, and the resulting females artificially fed to study the virus transmission. Furthermore, we studied the kinetics of WNV replication in ticks after infecting nymphs using an automatic injector. Active replication of WNV was detected in injected nymphs from day 7 post-infection until 28 dpi. In the nymphs infected by artificial feeding, the transstadial transmission of WNV was confirmed molecularly in 46.7% of males, while virus transmission during in vitro feeding of I. ricinus females originating from infected nymphs was not registered. The long persistence of WNV in I. ricinus ticks did not correlate with the transmission of the virus and it is unlikely that I. ricinus represents a competent vector. However, there is a potential reservoir role that this tick species can play, with hosts potentially acquiring the viral agent after ingesting the infected ticks.

scholarly journals Vector Competence of Italian Populations of Culicoides for Some Bluetongue Virus Strains Responsible for Recent Northern African and European Outbreaks

Viruses ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 941 ◽  
Author(s):  
Valentina Federici ◽  
Maria Goffredo ◽  
Giuseppe Mancini ◽  
Michela Quaglia ◽  
Adriana Santilli ◽  
...  
Keyword(s):  
Bluetongue Virus ◽  
Vector Competence ◽  
Oral Infection ◽  
Balearic Islands ◽  
Rt Pcr ◽  
Vector Species ◽  
Vaccination Programs ◽  
Culicoides Obsoletus ◽  
Culicoides Imicola ◽  
Virus Strains

The distribution of Bluetongue virus (BTV) in Europe can be represented by two distinct and interconnected epidemiological systems (episystems), each characterized by different ecological characteristics and vector species. This study investigated the vector competence of Italian populations of Culicoides imicola and Culicoides obsoletus/scoticus to some representative BTV strains after artificial oral infection. The BTV strains were selected according to their ability to spread to one or both episystems and included BTV-4 ITA, responsible of the recent Italian and French BTV-4 outbreaks; the BTV-2 strain which caused the first BTV incursion in Italy, Corsica, and Balearic Islands; BTV-4 MOR, responsible for the epidemic in Morocco; and BTV-8, the strain which spread through Europe between 2006 and 2008. Blood-soaked cotton pledgets and Hemotek membrane feeder using Parafilm® membrane were used to artificially feed midges. For each population/strain, recovery rates (positive/tested heads) were evaluated using serogroup- and serotype-specific RT-PCR. The trial demonstrated that, except for the Abruzzo population of C. obsoletus/C. scoticus, which was refractory to BTV-4 MOR infection, all the investigated Culicoides populations are susceptible to the selected BTV strains and that, if prompt vaccination programs and restriction measures had not been implemented, BTV-2 and BTV-4 MOR could have spread all over Europe.

scholarly journals Co-Circulation and Excretion Dynamics of Diverse Rubula- and Related Viruses in Egyptian Rousette Bats from South Africa

Viruses ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 37 ◽  
Author(s):  
Marinda Mortlock ◽  
Muriel Dietrich ◽  
Jacqueline Weyer ◽  
Janusz T. Paweska ◽  
Wanda Markotter
Keyword(s):  
South Africa ◽  
Temporal Dynamics ◽  
Virus Transmission ◽  
Sample Type ◽  
Limited Extent ◽  
Human Pathogens ◽  
Polymerase Gene ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Viral Excretion

The Egyptian rousette bat (Rousettus aegyptiacus) has previously been implicated as the natural host of a zoonotic rubulavirus; however, its association with rubulaviruses has been studied to a limited extent. Urine, spleen, and other organs collected from the R. aegyptiacus population within South Africa were tested with a hemi-nested RT-PCR assay targeting a partial polymerase gene region of viruses from the Avula- and Rubulavirus genera. Urine was collected over a 14-month period to study the temporal dynamics of viral excretion. Diverse rubulaviruses, including viruses related to human mumps and parainfluenza virus 2, were detected. Active excretion was identified during two peak periods coinciding with the host reproductive cycle. Analysis of additional organs indicated co-infection of individual bats with a number of different putative rubulaviruses, highlighting the limitations of using a single sample type when determining viral presence and diversity. Our findings suggest that R. aegyptiacus can harbor a range of Rubula- and related viruses, some of which are related to known human pathogens. The observed peaks in viral excretion represents potential periods of a higher risk of virus transmission and zoonotic disease spill-over.

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