Sentinel Site-Enhanced near-Real Time Surveillance Documenting West Nile Virus Circulation in Two Culex Mosquito Species Indicating Different Transmission Characteristics , Djibouti City , Djibouti

2012 ◽  
Vol 42 (2) ◽  
pp. 461-474 ◽  
Author(s):  
Michael K. Faulde ◽  
Michael Spiesberger ◽  
Babiker Abbas
Author(s):  
Reza ZEIDABADINEZHAD ◽  
Hassan VATANDOOST ◽  
Mohammad Reza ABAI ◽  
Navid DINPARAST DJADID ◽  
Abbasali RAZ ◽  
...  

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.


Author(s):  
Martina Ferraguti ◽  
Hans Heesterbeek ◽  
Josué Martínez‐de la Puente ◽  
Miguel Ángel Jiménez‐Clavero ◽  
Ana Vázquez ◽  
...  

Parasite ◽  
2017 ◽  
Vol 24 ◽  
pp. 3 ◽  
Author(s):  
Luciano Michaël Tantely ◽  
Catherine Cêtre-Sossah ◽  
Tsiriniaina Rakotondranaivo ◽  
Eric Cardinale ◽  
Sébastien Boyer

2013 ◽  
Vol 194 (1-2) ◽  
pp. 146-153 ◽  
Author(s):  
Stephanie M. Lim ◽  
Penelope Koraka ◽  
Albert D.M.E. Osterhaus ◽  
Byron E.E. Martina

2022 ◽  
Vol 16 (1) ◽  
pp. e0010075
Author(s):  
Giulia Mencattelli ◽  
Marie Henriette Dior Ndione ◽  
Roberto Rosà ◽  
Giovanni Marini ◽  
Cheikh Tidiane Diagne ◽  
...  

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.


2009 ◽  
Vol 6 (1) ◽  
pp. 55-59 ◽  
Author(s):  
Shi Li-Jun ◽  
Lu Mao-Min ◽  
Li Gang ◽  
Li Cheng-Yao ◽  
Zhang Jin-Gang

AbstractA rapid real-time polymerase chain reaction (RT-PCR) for detecting West Nile virus (WNV) was established. Primers were designed according to the sequence of the capsid protein gene of WNV by Primer Premier 5.0. In this way, an inexpensive assay using the intercalating dye SYBR Green I was developed and validated. The amplifying curve showed that this method could successfully amplify 102 copies/μl of the WNV gene, while reference to Japanese encephalitis virus (JEV) and blank control were all negative. Tenfold successive dilutions of positive WNV DNA were used to measure the sensitivity of RT-PCR. The assay system showed high reproducibility with coefficient of variation (CV) <2%. Thus the newly established RT-PCR assay was shown to be a rapid, sensitive and specific test for detecting WNV.


2007 ◽  
Vol 146 (1-2) ◽  
pp. 355-358 ◽  
Author(s):  
Sonja Linke ◽  
Heinz Ellerbrok ◽  
Matthias Niedrig ◽  
Andreas Nitsche ◽  
Georg Pauli

Author(s):  
Jefferson A Vaughan ◽  
Juanita Hinson ◽  
Elizabeth S Andrews ◽  
Michael J Turell

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, &gt;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.


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