West Nile virus in Tunisia, 2014: First isolation from mosquitoes

BackgroundThe Culex pipiens complex (Diptera: Culicidae) includes the most widespread mosquito species in the world. Members of this complex are the primary enzootic and epidemic vectors of the West Nile virus (genus Flavivirus) in several countries. The two recognized forms of Cx. pipiens (Linnaeus, 1758) - pipiens and molestus - exhibit behavioral and physiological differences. Natural populations of Cx. pipiens were investigated in several sites in Tunisia to evaluate the ecophysiological and molecular characteristics of their forms.ResultsThe analysis showed the sympatric presence of Cx. pipiens forms and hybrids in all studied sites. Of all the tested larvae of Cx. pipiens, 33.5% were identified as pipiens, 30.8% were identified as molestus, and 35.6% were identified as hybrids. The molestus and hybrid forms were positively correlated with urban habitats and belowground sites while the pipiens form was positively correlated with rural habitats and aboveground sites. Autogeny was expressed in all types of habitats and breeding sites. By contrast with the microsatellite CQ11, the two molecular markers, ace-2 and cytb, did not allow differentiation between the Cx. pipiens forms.ConclusionsOur study shows the ubiquitous distribution and the plasticity of the different forms of Cx. pipiens in a wide range of ecological conditions. It suggests that the behavioral traits assigned to the forms of Cx. pipiens seem to be more flexible than previously assumed. Our analysis also proves that the microsatellite CQ11 remains an efficient tool for distinguishing between Cx. pipiens forms.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-017-2265-7) contains supplementary material, which is available to authorized users.

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“…This mosquito species occurs throughout temperate latitudes and is involved in the transmission of West Nile virus in Tunisia [5, 34]. …”

Section: Discussionmentioning

confidence: 99%

Ecophysiological characterization and molecular differentiation of Culex pipiens forms (Diptera: Culicidae) in Tunisia

et al. 2017

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“…During the summer-autumn of 2012, a WNV infection outbreak occurred in Tunisia after an apparent silent period following the 2003 epidemic, although epidemiological and clinical surveys have demonstrated WNV circulation in humans 5 , 10 – 12 , as well as in mosquitoes 24 , and seropositivity has been reported in equids 20 – 22 , dromedaries 23 , and wild birds 19 in the years since the first WNV epidemic in 1997. However, to date, no information on the epidemiological characteristics of the WNV transmission cycle in the Tunisian Sahel region has been available.…”

Section: Discussionmentioning

confidence: 99%

“…Entomological surveys conducted after WNV outbreaks in Tunisia showed the abundance and role of Cx. pipiens as potential WNV vectors in Tunisia 11 , 24 , 26 , 51 , 52 . WNV-positive Cx.…”

Section: Discussionmentioning

confidence: 99%

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A four-year survey (2011–2014) of West Nile virus infection in humans, mosquitoes and birds, including the 2012 meningoencephalitis outbreak in Tunisia

Monastiri

Mechri

Vázquez

et al. 2018

Emerging Microbes & Infections

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A West Nile virus (WNV) outbreak occurred in Tunisia between mid-July and December 2012. To assess the epidemiological features of the WNV transmission cycle, human cerebrospinal fluid samples from patients with suspected cases (n = 79), Culex pipiens mosquitoes (n = 583) and serum specimens from domestic and migratory birds (n = 70) were collected for 4 years (2011–2014) in the Tunisian Sahel region. Viral testing was performed by polymerase chain reaction (PCR). The WNV genome was detected in 7 patients (8.8%), 4 Culex pipiens pools, and a domestic mallard (Anas platyrhynchos). All PCR-positive samples were from the Monastir region. Phylogenetic analysis revealed that two different WNV strain groups circulated, and isolates from the reservoir (bird), vector (Culex pipiens), and dead-end hosts (humans) were closely related. The Monastir region is a hot-spot for WNV infection, and the reiterative presence of WNV over the years has increased the risk of viral reemergence in Tunisia, which highlights the need for more enhanced and effective WNV surveillance in humans with public awareness campaigns strengthened by monitoring mosquitoes and maintaining avian surveillance for early detection of WNV circulation.

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“…In addition to their nuisance, mosquitoes cause vector-borne diseases [1][2][3] and their impact on human health is very considerable [4]. Worldwide, mosquito species such as Culex are responsible for the transmission of parasitic diseases such as filariasis, yellow fever and West Nile virus [5,6].…”

Section: Introductionmentioning

confidence: 99%

Pirimiphos-Methyl Resistance Status of Field Populations of Culex pipiens (Diptera: Culicidae) From Grand Tunis Area, Northeast Tunisia

Tabbabi¹,

Daaboub²,

Laamari³

et al. 2017

Hereditary Genet

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Mosquito species are responsible for the transmission of many parasitic diseases and their control leads to the phenomenon of resistance to insecticides. Five Culex pipiens samples were collected from various localities of Grand Tunis area, Northeast Tunisia, between June 2003 and November 2005. All the studied samples were resistant to pirimiphos methyl (organophosphorus insecticide). Our results showed the implication of insensitive acetylcholinesterase and overproduced esterases in the résistance of the Tunisian populations of Culex pipiens. Results were discussed in relation to resistance mechanism.

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West Nile virus in Tunisia, 2014: First isolation from mosquitoes

Cited by 17 publications

References 28 publications

Ecophysiological characterization and molecular differentiation of Culex pipiens forms (Diptera: Culicidae) in Tunisia

Ecophysiological characterization and molecular differentiation of Culex pipiens forms (Diptera: Culicidae) in Tunisia

A four-year survey (2011–2014) of West Nile virus infection in humans, mosquitoes and birds, including the 2012 meningoencephalitis outbreak in Tunisia

Pirimiphos-Methyl Resistance Status of Field Populations of Culex pipiens (Diptera: Culicidae) From Grand Tunis Area, Northeast Tunisia

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