Vector competence of certain Culex and Aedes mosquitoes for the Chittoor virus, the Indian variant of the Batai virus

2018 ◽  
Vol 64 (8) ◽  
pp. 581-588
Author(s):  
A.B. Sudeep ◽  
Neda Shaikh ◽  
Y.S. Ghodke ◽  
V.S. Ingale ◽  
M.D. Gokhale
Keyword(s):  
Neutralizing Antibodies ◽  
Vector Competence ◽  
Mosquito Species ◽  
Horizontal Transmission ◽  
Clinical Manifestations ◽  
Hemorrhagic Fever ◽  
Wide Distribution ◽  
Genetic Reassortment ◽  
Aedes Mosquitoes ◽  
Batai Virus

Chittoor virus (CHITV), a mosquito-borne bunyavirus (Orthobunyavirus: Bunyaviridae) isolated in India, has been found to be antigenically close to the Batai virus (BATV), which has a wide distribution across Asia, Europe, and Africa. The latter virus causes influenza-like illness in humans and mild illness in sheep and goats. BATV has been involved in genetic reassortment with other bunyaviruses, generating novel genome combinations and causing severe clinical manifestations including hemorrhagic fever. Conversely, CHITV has never been associated with any major outbreaks in India, although neutralizing antibodies have been detected in humans and domestic animals. Repeated isolations and seroprevalence have prompted us to determine the vector competence of three important mosquito species, viz., Culex quinquefasciatus, Culex tritaeniorhynchus, and Aedes aegypti, for CHITV. The three mosquito species replicated CHITV to titers of 6.3, 5.0, and 5.2 log10 TCID50/mL, respectively, and maintained the virus for substantial periods. Both of the Culex species demonstrated vector competence, while A. aegypti did not. Horizontal transmission to infant mice was also demonstrated by both Culex species. Active circulation of the virus and the availability of both susceptible hosts and competent vector mosquitoes pose a serious threat to public health should there be a reassortment.

A Simple PCR Assay for Discrimination of Dengue Vectors from Nsukka LGA, Nigeria

2020 ◽  
Vol 10 (1) ◽  
pp. 67-77
Author(s):  
Amos Watentena ◽  
Ikem Chris Okoye ◽  
Ikechukwu Eugene Onah ◽  
Onwude Cosmas Ogbonnaya ◽  
Emmanuel Ogudu
Keyword(s):  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Mosquito Species ◽  
Public Health Problem ◽  
Major Public Health Problem ◽  
Mosquito Vector ◽  
Aedes Mosquitoes ◽  
Allele Specific ◽  
Arboviral Diseases ◽  
Dengue Vectors

Mosquitoes of Aedes species are vectors of several arboviral diseases which continue to be a major public health problem in Nigeria. This study among other things, morphologically identified Aedes mosquitoes collected from Nsukka LGA and used an allele specific PCR amplification for discrimination of dengue vectors. Larval sampling, BG-sentinel traps and modified human landing catches were used for mosquito sampling in two selected autonomous communities of Nsukka LGA (Nsukka and Obimo). A total of 124 Aedes mosquitoes consisting of five (5) different species were collected from April to June, 2019 in a cross-sectional study that covered 126 households, under 76 distinct geographical coordinates. Larvae was mainly collected from plastic containers 73% (n=224), metallic containers 14% (n=43), earthen pots 9% (n=29) and used car tyres 3% (n=9), reared to adult stage 69.35% (n=86), and all mosquitoes were identified using standard morphological keys. Five (5) Aedes mosquito species were captured; Aedes aegypti 83(66.94%), Aedes albopictus 33(26.61%), Aedes simpsoni (4.48%), Aedes luteocephalus (≤1%) and Aedes vittatus (≤1%). Nsukka autonomous community had higher species diversity than Obimo. Allele specific amplification confirmed dengue vectors, Aedes aegypti and Aedes albopictus species on a 2% agarose gel. Since the most recent re-emergence of arboviral diseases is closely associated with Aedes species, findings of this study, therefore, give further evidence about the presence of potential arboviral vectors in Nigeria and describe the role of a simple PCR in discriminating some. Further entomological studies should integrate PCR assays in mosquito vector surveillance.

scholarly journals Microbiota identified from preserved Anopheles

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Bianca E Silva ◽  
Zvifadzo Matsena Zingoni ◽  
Lizette L. Koekemoer ◽  
Yael L. Dahan-Moss
Keyword(s):  
Microbial Diversity ◽  
Vector Competence ◽  
Mosquito Species ◽  
Anopheles Funestus ◽  
Cost Effective ◽  
Diversity Indices ◽  
Malaria Vectors ◽  
Microbial Composition ◽  
Culture Independent ◽  
Culture Dependent

Abstract Background Mosquito species from the Anopheles gambiae complex and the Anopheles funestus group are dominant African malaria vectors. Mosquito microbiota play vital roles in physiology and vector competence. Recent research has focused on investigating the mosquito microbiota, especially in wild populations. Wild mosquitoes are preserved and transported to a laboratory for analyses. Thus far, microbial characterization post-preservation has been investigated in only Aedes vexans and Culex pipiens. Investigating the efficacy of cost-effective preservatives has also been limited to AllProtect reagent, ethanol and nucleic acid preservation buffer. This study characterized the microbiota of African Anopheles vectors: Anopheles arabiensis (member of the An. gambiae complex) and An. funestus (member of the An. funestus group), preserved on silica desiccant and RNAlater® solution. Methods Microbial composition and diversity were characterized using culture-dependent (midgut dissections, culturomics, MALDI-TOF MS) and culture-independent techniques (abdominal dissections, DNA extraction, next-generation sequencing) from laboratory (colonized) and field-collected mosquitoes. Colonized mosquitoes were either fresh (non-preserved) or preserved for 4 and 12 weeks on silica or in RNAlater®. Microbiota were also characterized from field-collected An. arabiensis preserved on silica for 8, 12 and 16 weeks. Results Elizabethkingia anophelis and Serratia oryzae were common between both vector species, while Enterobacter cloacae and Staphylococcus epidermidis were specific to females and males, respectively. Microbial diversity was not influenced by sex, condition (fresh or preserved), preservative, or preservation time-period; however, the type of bacterial identification technique affected all microbial diversity indices. Conclusions This study broadly characterized the microbiota of An. arabiensis and An. funestus. Silica- and RNAlater®-preservation were appropriate when paired with culture-dependent and culture-independent techniques, respectively. These results broaden the selection of cost-effective methods available for handling vector samples for downstream microbial analyses.

scholarly journals Yellow Fever Outbreak in Eastern Senegal, 2020–2021

Viruses ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1475
Author(s):  
Moussa Moïse Diagne ◽  
Marie Henriette Dior Ndione ◽  
Alioune Gaye ◽  
Mamadou Aliou Barry ◽  
Diawo Diallo ◽  
...  
Keyword(s):  
Yellow Fever ◽  
Yellow Fever Virus ◽  
Mosquito Species ◽  
Virus Transmission ◽  
Genomic Analysis ◽  
Hemorrhagic Fever ◽  
Fever Virus ◽  
World Health ◽  
Effective Vaccine ◽  
Ministry Of Health

Yellow fever virus remains a major threat in low resource countries in South America and Africa despite the existence of an effective vaccine. In Senegal and particularly in the eastern part of the country, periodic sylvatic circulation has been demonstrated with varying degrees of impact on populations in perpetual renewal. We report an outbreak that occurred from October 2020 to February 2021 in eastern Senegal, notified and managed through the synergistic effort yellow fever national surveillance implemented by the Senegalese Ministry of Health in collaboration with the World Health Organization, the countrywide 4S network set up by the Ministry of Health, the Institut Pasteur de Dakar, and the surveillance of arboviruses and hemorrhagic fever viruses in human and vector populations implemented since mid 2020 in eastern Senegal. Virological analyses highlighted the implication of sylvatic mosquito species in virus transmission. Genomic analysis showed a close relationship between the circulating strain in eastern Senegal, 2020, and another one from the West African lineage previously detected and sequenced two years ago from an unvaccinated Dutch traveler who visited the Gambia and Senegal before developing signs after returning to Europe. Moreover, genome analysis identified a 6-nucleotide deletion in the variable domain of the 3′UTR with potential impact on the biology of the viral strain that merits further investigations. Integrated surveillance of yellow fever virus but also of other arboviruses of public health interest is crucial in an ecosystem such as eastern Senegal.

scholarly journals Epidemiology of West Nile virus in Africa: An underestimated threat

2022 ◽  
Vol 16 (1) ◽  
pp. e0010075
Author(s):  
Giulia Mencattelli ◽  
Marie Henriette Dior Ndione ◽  
Roberto Rosà ◽  
Giovanni Marini ◽  
Cheikh Tidiane Diagne ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Disease Burden ◽  
Vector Competence ◽  
Mosquito Species ◽  
Global Scale ◽  
Reference List ◽  
African Continent ◽  
West Nile ◽  
Scientific Papers ◽  
Epidemiological Pattern

Background West Nile virus is a mosquito-borne flavivirus which has been posing continuous challenges to public health worldwide due to the identification of new lineages and clades and its ability to invade and establish in an increasing number of countries. Its current distribution, genetic variability, ecology, and epidemiological pattern in the African continent are only partially known despite the general consensus on the urgency to obtain such information for quantifying the actual disease burden in Africa other than to predict future threats at global scale. Methodology and principal findings References were searched in PubMed and Google Scholar electronic databases on January 21, 2020, using selected keywords, without language and date restriction. Additional manual searches of reference list were carried out. Further references have been later added accordingly to experts’ opinion. We included 153 scientific papers published between 1940 and 2021. This review highlights: (i) the co-circulation of WNV-lineages 1, 2, and 8 in the African continent; (ii) the presence of diverse WNV competent vectors in Africa, mainly belonging to the Culex genus; (iii) the lack of vector competence studies for several other mosquito species found naturally infected with WNV in Africa; (iv) the need of more competence studies to be addressed on ticks; (iv) evidence of circulation of WNV among humans, animals and vectors in at least 28 Countries; (v) the lack of knowledge on the epidemiological situation of WNV for 19 Countries and (vii) the importance of carrying out specific serological surveys in order to avoid possible bias on WNV circulation in Africa. Conclusions This study provides the state of art on WNV investigation carried out in Africa, highlighting several knowledge gaps regarding i) the current WNV distribution and genetic diversity, ii) its ecology and transmission chains including the role of different arthropods and vertebrate species as competent reservoirs, and iii) the real disease burden for humans and animals. This review highlights the needs for further research and coordinated surveillance efforts on WNV in Africa.

scholarly journals Wolbachia prevalence in the vector species Culex pipiens and Culex torrentium in a Sindbis virus-endemic region of Sweden

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Alexander Bergman ◽  
Jenny C. Hesson
Keyword(s):  
Culex Pipiens ◽  
Sindbis Virus ◽  
Vector Competence ◽  
Horizontal Transmission ◽  
Vector Species ◽  
Endemic Region ◽  
Species Determination ◽  
Terrestrial Arthropods ◽  
Endosymbiotic Bacteria ◽  
Vector Borne

Abstract Background Wolbachia pipientis are endosymbiotic bacteria present in a large proportion of terrestrial arthropods. The species is known to sometimes affect the ability of its host to transmit vector-borne pathogens. Central Sweden is endemic for Sindbis virus (SINV), where it is mainly transmitted by the vector species Culex pipiens and Culex torrentium, with the latter established as the main vector. In this study we investigated the Wolbachia prevalence in these two vector species in a region highly endemic for SINV. Methods Culex mosquitoes were collected using CDC light traps baited with carbon dioxide over 9 years at 50 collection sites across the River Dalälven floodplains in central Sweden. Mosquito genus was determined morphologically, while a molecular method was used for reliable species determination. The presence of Wolbachia was determined through PCR using general primers targeting the wsp gene and sequencing of selected samples. Results In total, 676 Cx. pipiens and 293 Cx. torrentium were tested for Wolbachia. The prevalence of Wolbachia in Cx. pipiens was 97% (95% CI 94.8–97.6%), while only 0.7% (95% CI 0.19–2.45%) in Cx. torrentium. The two Cx. torrentium mosquitoes that were infected with Wolbachia carried different types of the bacteria. Conclusions The main vector of SINV in the investigated endemic region, Cx. torrentium, was seldom infected with Wolbachia, while it was highly prevalent in the secondary vector, Cx. pipiens. The presence of Wolbachia could potentially have an impact on the vector competence of these two species. Furthermore, the detection of Wolbachia in Cx. torrentium could indicate horizontal transmission of the endosymbiont between arthropods of different species. Graphical abstract

scholarly journals The conservation of a core virome in Aedes mosquitoes across different developmental stages and continents

2020 ◽  
Author(s):  
Chenyan Shi ◽  
Lu Zhao ◽  
Evans Atoni ◽  
Weifeng Zeng ◽  
Xiaomin Hu ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Vector Competence ◽  
Metagenomic Dataset ◽  
Aedes Mosquitoes ◽  
Stable Species ◽  
Core Set ◽  
Laboratory Colonies ◽  
Novel Virus ◽  
Species Specific ◽  
Great Burden

AbstractMosquitoes belonging to the genus Aedes can efficiently transmit many pathogenic arboviruses, placing a great burden on public health worldwide. In addition, they also carry a number of insect specific viruses (ISVs), and it was recently suggested that some of these ISVs might form a stable species-specific “core virome” in mosquito populations. However, little is known about such a core virome in laboratory colonies and if it is present across different developmental stages. In this study, we compared the viromes in eggs, larvae, pupae and adults of Aedes albopictus mosquitoes collected from the field as well as from a lab colony. The virome in lab-derived Ae. albopictus is very stable across all stages, consistent with a vertical transmission route of these viruses, forming a “vertically transmitted core virome”. The different stages of field collected Ae. albopictus mosquitoes also contains this stable vertically transmitted core virome as well as another set of viruses shared by mosquitoes across different stages, which might be an “environment derived core virome”. Both these vertically and environmentally transmitted core viromes in Ae. albopictus deserve more attention with respect to their effects on vector competence for important medically relevant arboviruses. To further study this core set of ISVs, we screened 46 publically available SRA viral metagenomic dataset of mosquitoes belonging to the genus Aedes. Some of the identified core ISVs are identified in the majority of SRAs. In addition, a novel virus, Aedes phasmavirus, is found to be distantly related to Yongsan bunyavirus 1, and the genomes of the core virus Phasi Charoen-like phasivirus is highly prevalent in the majority of the tested samples, with nucleotide identities ranging from 94% to 99%. Finally, Guadeloupe mosquito virus, and some related viruses formed three separated phylogenetic clades. How these core ISVs influence the biology of mosquito host, arboviruses infection and evolution deserve to be further explored.

BACKGROUND OF THE CCHF PATHOGEN CIRCULATION IN THE SOUTHERN REGION OF KAZAKHSTAN AND LABORATORY DIAGNOSTICS OF THE CONGO-CRIMEAN HEMORRHAGIC FEVER

Vestnik ◽  
2021 ◽  
pp. 29-34
Author(s):  
У.А. Укибаева ◽  
Г.М. Омашева ◽  
А.Б. Даниярова ◽  
Э.У. Бойбосинов ◽  
А.А. Белходжаев ◽  
...  
Keyword(s):  
Laboratory Tests ◽  
Molecular Genetic ◽  
Clinical Manifestations ◽  
Hemorrhagic Fever ◽  
Southern Region ◽  
Favorable Outcome ◽  
Laboratory Evaluation ◽  
Laboratory Diagnostics ◽  
Timely Diagnosis ◽  
Adequate Therapy

Своевременная диагностика ККГЛ, прогнозирование геморрагического синдрома и адекватная терапия часто определяют благоприятный исход заболевания. Лабораторная оценка клинических проявлений ККГЛ проводится гематологическими, биохимическими, гемостазиологическими лабораторными испытаниями. Подтверждение диагноза осуществляется иммунологическими, молекулярно-генетическими и вирусологическими методами. Timely diagnosis of CCHF, prognosis of hemorrhagic syndrome and adequate therapy often determine a favorable outcome of the disease. Laboratory evaluation of clinical manifestations of CCHF is carried out by hematological, biochemical, and hemostasiological laboratory tests. Confirmation of the diagnosis is carried out by immunological, molecular-genetic and virological methods.

Alphaviruses

2010 ◽  
pp. 557-561
Author(s):  
E.E. Ooi ◽  
L.R. Petersen ◽  
D.J. Gubler
Keyword(s):  
Mosquito Species ◽  
Clinical Manifestations ◽  
Febrile Illness ◽  
Domestic Animals ◽  
Human Infection ◽  
Tissue Samples ◽  
The Family ◽  
Polymerase Chain ◽  
Complex Transmission ◽  
Diagnosis Of Infection

There are 29 registered alphaviruses belonging to the family Togaviridae, 16 of which are known to cause human infection. They are RNA viruses with global geographical distribution and complex transmission cycles between wild or domestic animals or birds and one or more mosquito species; humans are infected by mosquito bites. They cause a spectrum of clinical manifestations ranging from nonspecific febrile illness to acute encephalitis and death. Diagnosis of infection is made serologically by detection of IgM and IgG antibodies, virus isolation, and polymerase chain reaction, or by immunohistochemistry on tissue samples....

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