scholarly journals Pre-existing Microfilarial Infections of American Robins (Passeriformes: Turdidae) and Common Grackles (Passeriformes: Icteridae) Have Limited Impact on Enhancing Dissemination of West Nile Virus in Culex pipiens Mosquitoes (Diptera: Culicidae)

2020 ◽  
Author(s):  
Jefferson A Vaughan ◽  
Juanita Hinson ◽  
Elizabeth S Andrews ◽  
Michael J Turell
Keyword(s):  
West Nile Virus ◽  
Viral Infection ◽  
Culex Pipiens ◽  
Mosquito Species ◽  
Immature Stages ◽  
West Nile ◽  
Limited Impact ◽  
Nematode Parasites ◽  
American Robins ◽  
Specific Virus

Abstract Microfilariae (MF) are the immature stages of filarial nematode parasites and inhabit the blood and dermis of all classes of vertebrates, except fish. Concurrent ingestion of MF and arboviruses by mosquitoes can enhance mosquito transmission of virus compared to when virus is ingested alone. Shortly after being ingested, MF penetrate the mosquito’s midgut and may introduce virus into the mosquito’s hemocoel, creating a disseminated viral infection much sooner than normal. This phenomenon is known as microfilarial enhancement. Both American Robins and Common Grackles harbor MF—that is, Eufilaria sp. and Chandlerella quiscali von Linstow (Spirurida: Onchocercidae), respectively. We compared infection and dissemination rates in Culex pipiens L. mosquitoes that fed on birds with and without MF infections that had been infected with West Nile virus (WNV). At moderate viremias, about 107 plaque-forming units (pfu)/ml of blood, there were no differences in infection or dissemination rates among mosquitoes that ingested viremic blood from a bird with or without microfilaremia. At high viremias, >108.5 pfu/ml, mosquitoes feeding on a microfilaremic Grackle with concurrent viremia had significantly higher infection and dissemination rates than mosquitoes fed on viremic Grackles without microfilaremia. Microfilarial enhancement depends on the specific virus, MF, and mosquito species examined. How virus is introduced into the hemocoel by MF differs between the avian/WNV systems described here (i.e., leakage) and various arboviruses with MF of the human filarid, Brugia malayi (Brug) (Spirurida: Onchocercidae) (i.e., cotransport). Additional studies are needed to determine if other avian species and their MF are involved in the microfilarial enhancement of WNV in nature.

Target Site Insensitivity Detection in Deltamethrin Resistant Culex pipiens Complex in Iran

2020 ◽  
Author(s):  
Reza ZEIDABADINEZHAD ◽  
Hassan VATANDOOST ◽  
Mohammad Reza ABAI ◽  
Navid DINPARAST DJADID ◽  
Abbasali RAZ ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Insecticide Resistance ◽  
Real Time ◽  
Real Time Pcr ◽  
Culex Pipiens ◽  
Mosquito Species ◽  
Knockdown Resistance ◽  
West Nile ◽  
Culex Pipiens Complex ◽  
Novel Approach

Background: Some mosquito species which belong to the Culex. pipiens complex are primary vectors for West Nile virus, Sindbis, Dirofilaria immitis, and many arboviruses. Knockdown resistance (kdr) mutations in the voltage-gated sodium channel (VGSC) gene of Cx. pipiens that is inherited, is one of the important threats for the efficacy of pyrethroids insecticides. Knockdown resistance (kdr) mutation, L1014F, is a well-defined mechanism of resistance to pyrethroids and DDT in many insect species. The aim of study was to determine the mechanisms of Insecticide resistance in this species Methods: Specimens of Cx. pipiens, the major vector of West Nile virus, were obtained in Tehran, Iran by collecting larvae from polluted wastewater in Qarchak of Tehran. In 2016 Insecticide susceptibility tests were performed according to WHO methods with deltamethrin 0.05%. We focused on determination of this point mutation in the VGSC gene of Cx. pipiens by Real-time PCR. Results: Our results revealed high levels of resistance to deltamethrin 0.05%. The lethal times i.e. LT50 and LT90 for deltamethrin were 2.1530 and 8.5117 h respectively. The result of Real-time PCR confirmed the presence of resistant genotype in all the members of tested population. This study is the first report on kdr genotyping of Cx. pipiens from Tehran and our results on the VGSC gene in position L1014F confirmed the TTA to TTT nucleotide change. Conclusion: This finding will provide a clue for management of insecticide resistance in mosquito which are vectors of arboviruses and decision for replacement of novel approach for vector control.

scholarly journals Surveillance of West Nile virus infection in Kashgar Region, Xinjiang, China, 2013–2016

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yanping Zhang ◽  
Wenwen Lei ◽  
Yali Wang ◽  
Haitian Sui ◽  
Bo Liu ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Neutralizing Antibodies ◽  
Culex Pipiens ◽  
Mosquito Species ◽  
Mainland China ◽  
West Nile Virus Infection ◽  
Viral Meningitis ◽  
Immunoglobulin M ◽  
West Nile ◽  
Epidemiological Characteristics

AbstractWest Nile virus (WNV) was first isolated in mainland China from mosquitoes in Jiashi County, Kashgar Region, Xinjiang in 2011, following local outbreaks of viral meningitis and encephalitis caused by WNV. To elaborate the epidemiological characteristics of the WNV, surveillance of WNV infection in Kashgar Region, Xinjiang from 2013 to 2016 were carried out. Blood and CSF samples from surveillance human cases, blood of domestic chicken, cattle, sheep and mosquitoes in Kashgar Region were collected and detected. There were human 65 WNV Immunoglobulin M (IgM) antibody positive cases by ELISA screening, 6 confirmed WNV cases by the plaque reduction neutralization test (PRNT) screening. These cases occurred mainly concentrated in August to September of each year, and most of them were males. WNV-neutralizing antibodies were detected in both chickens and sheep, and the positive rates of neutralizing antibodies were 15.5% and 1.78%, respectively. A total of 15,637 mosquitoes were collected in 2013–2016, with Culex pipiens as the dominant mosquito species. Four and 1 WNV-positive mosquito pools were detected by RT-qPCR in 2013 and 2016 respectively. From these data, we can confirm that Jiashi County may be a natural epidemic foci of WNV disease, the trend highlights the routine virology surveillance in WNV surveillance cases, mosquitoes and avian should be maintained and enhanced to provide to prediction and early warning of outbreak an epidemic of WNV in China.

scholarly journals Screening of Mosquitoes for West Nile Virus and Usutu Virus in Croatia, 2015–2020

2021 ◽  
Vol 6 (2) ◽  
pp. 45
Author(s):  
Ana Klobucar ◽  
Vladimir Savic ◽  
Marcela Curman Posavec ◽  
Suncica Petrinic ◽  
Urska Kuhar ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Culex Pipiens ◽  
Rt Pcr ◽  
West Nile ◽  
Usutu Virus ◽  
Culex Pipiens Complex ◽  
Mammalian Origin ◽  
Mosquito Pool ◽  
The City ◽  
Generation Sequencing

In the period from 2015 to 2020, an entomological survey for the presence of West Nile virus (WNV) and Usutu virus (USUV) in mosquitoes was performed in northwestern Croatia. A total of 20,363 mosquitoes were sampled in the City of Zagreb and Međimurje county, grouped in 899 pools and tested by real-time RT-PCR for WNV and USUV RNA. All pools were negative for WNV while one pool each from 2016 (Aedes albopictus), 2017 (Culex pipiens complex), 2018 (Cx. pipiens complex), and 2019 (Cx. pipiens complex), respectively, was positive for USUV. The 2018 and 2019 positive pools shared 99.31% nucleotide homology within the USUV NS5 gene and both clustered within USUV Europe 2 lineage. The next-generation sequencing of one mosquito pool (Cx. pipiens complex) collected in 2018 in Zagreb confirmed the presence of USUV and revealed several dsDNA and ssRNA viruses of insect, bacterial and mammalian origin.

scholarly journals Population dynamics of mosquito species in a West Nile virus endemic area in Madagascar

Parasite ◽  
2017 ◽  
Vol 24 ◽  
pp. 3 ◽  
Author(s):  
Luciano Michaël Tantely ◽  
Catherine Cêtre-Sossah ◽  
Tsiriniaina Rakotondranaivo ◽  
Eric Cardinale ◽  
Sébastien Boyer
Keyword(s):  
Population Dynamics ◽  
West Nile Virus ◽  
Endemic Area ◽  
Mosquito Species ◽  
West Nile

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.

Sign in / Sign up

Export Citation Format

Share Document