Seroprevalence of West Nile virus in horses in different Moroccan regions

Benjelloun, Abdennasser; Harrak, Mehdi El; Calistri, Paolo; Loutfi, Chafiqa; Kabbaj, Hafsa; Conte, Annamaria; Ippoliti, Carla; Danzetta, Maria Luisa; Belkadi, Bouchra

doi:10.1002/vms3.71

Cited by 23 publications

(26 citation statements)

References 24 publications

(32 reference statements)

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“…Benjelloun and his collaborators studied seroprevalence of WNV in different regions of Morocco in 2011. They found a seroprevalence rate of WNV similar to our study 35% and 31% respectively by cELISA and MNT (Benjelloun et al, 2017). Another study carried out with 297 military working horses and 231 dogs in Morocco have described, respectively, a rate of 60% and 62% of seroprevalence by cELISA (Durand et al, 2016).…”

Section: Discussionsupporting

confidence: 87%

“…WNV has been circulating for a very long time in the Mediterranean region (Murgue et al, 2001) affecting mainly humans and horses (Benjelloun et al, 2016;Johnson et al, 2018;Papa, 2019). In Morocco, several outbreaks of WNV have been reported: (i) in 1996 with 94 equine cases including 42 deaths and only one human case (El Harrack et al, 1997;Tber Abdelhaq, 1996), (ii) in September and October of 2003 when WNV circulated among horses in Kenitra (Schuffenecker et al, 2005), (iii) in in horses (World Animal Health Information Database, 2010 ;Benjelloun et al, 2017;Durand et al, 2016;El Rhaffouli et al, 2013). The two strains of WNV (outbreaks in 1996 and 2003) belonged to clade 1a of lineage 1 (schuffenecker et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

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Evidence of circulation of West Nile virus in Culex pipiens mosquitoes and horses in Morocco

et al. 2020

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West Nile virus (WNV) is one of the most widely distributed mosquito-borne viruses in the world. In North Africa, it causes human cases of meningoencephalitis with fatalities in Algeria and in Tunisia, whereas only horses were affected in Morocco. The aims of this study were to detect WNV in mosquitoes and to determine seroprevalence of WNV in Moroccan horses by the detection of IgG antibodies. A total of 1,455 mosquitoes belonging to four different species were grouped by collection site, date, and sex with 10 specimens per pool and tested for 38 arboviruses using a high-throughput chip based on the BioMark Dynamic array system. Out of 146 mosquito pools tested, one pool was positive for WNV. This positive pool was confirmed by real time RT-PCR. The serosurvey showed that 33.7% (31/92) of horses were positive for competitive enzyme-linked immunosorbent assay (cELISA) test. The flavivirus-sphere microsphere immnoassay (MIA) test, targeting three flaviviruses (WNV, Usutu virus (USUV) and Tick borne encephalitic virus (TBEV)) showed that 23 sera out of 31 were positive for WNV, two for USUV, two for USUV or WNV, and four for an undetermined flavivirus. Virus neutralization tests with USUV and WNV showed that 28 of 31 sera were positive for WNV and all sera were negative for USUV. This study reports, for the first time, the detection of WNV from Culex pipiens mosquitoes in Morocco and its circulation among horses. This highlights that the detection of arboviruses in mosquitoes could serve as an early warning signal of a viral activity to prevent future outbreaks in animals and humans.

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Section: Discussionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Evidence of circulation of West Nile virus in Culex pipiens mosquitoes and horses in Morocco

et al. 2020

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“…West Nile Virus (WNV), Flavivirus: Flaviviridae, is an important mosquito-borne virus inducing a zoonotic disease called West Nile fever (WNF). The virus is transmitted by mosquitoes as biological vectors, birds as a natural reservoir, and equines and humans representing dead-end hosts (Calistri et al, 2010;Benjelloun et al, 2017). The temperature plays an important role in speeding the cycle, the transmission period, as well as on the survival of mosquitoes (Elhaig et al, 2017;Selim et al, 2018); whenever the local ecological conditions are appropriate for viral amplification, humans and equines could easily be infected (Komar et al, 2001;DeGroote et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

The Recent Update of the Situation of West Nile Fever among Equids in Egypt after Three Decades of Missing Information

Selim¹,

Radwan²,

Arnaout³

et al. 2019

PVJ

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West Nile virus (WNV) is a viral disease transmitted by mosquitoes to equids and has a zoonotic impact on humans. Although the WNV infection was reported in many countries in the Middle East; a little is known about its prevalence in equine populations in Egypt for the last three decades. We have carried out serosurvey on 400 horses and 150 donkeys in five governorates located in northern Egypt. Antibodies against WNV were found in 83 samples (seroprevalence 20.7%) in horses and 19 (seroprevalence 12.7%) in donkeys. Some risk factors for seropositivity to WNV infection in Egypt as the breed, age, and sex of horses were identified; it is more prevalent among gelding, mixed breed, and the middle age of horses. The infection could be attributed to the absence of control measures or vaccine programs besides the suitable habitat which enhances vector bioavailability. This study revealed the circulation of WNV in northern Egypt; as a result, there is a potential risk of exposure to human populations and there is a necessity for further assessment of the disease circumstances in the upcoming years in Egypt to control it.

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“…However, as most WNV infections in horses are asymptomatic or consist of a mild fever, cases can be missed when using syndromic surveillance alone. In surveys from European and African countries, WNV IgM antibodies have been used to detect recent infection in dead-end hosts, such as horses [ 4 , 6 ]. Our dataset contains a comparable number of sentinel horses from a region of the UK that is hypothesised to be at higher risk of WNV emergence as it is considered to be at higher risk for the introduction of other arthropod-borne viruses such as bluetongue virus [ 13 ].…”

Section: Discussionmentioning

confidence: 99%

“…Critically, early detection of the emergence and transmission of a virus enables public health and veterinary services to plan for potential cases and helps to achieve more general epidemiological monitoring. One method for the early detection of WNV is the serosurveillance of sentinel horses, as reported from Spain [ 4 ], Germany [ 5 ] and Africa [ 6 ], for example. However, confounding factors in serosurveillance studies are the use of vaccination and potential serum cross-reactivity with related viruses [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

Equine seroprevalence of West Nile virus antibodies in the UK in 2019

et al. 2020

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Background West Nile virus (WNV) is a single-stranded RNA virus that can cause neurological disease in both humans and horses. Due to the movement of competent vectors and viraemic hosts, WNV has repeatedly emerged globally and more recently in western Europe. Within the UK, WNV is a notifiable disease in horses, and vaccines against the virus are commercially available. However, there has been no investigation into the seroprevalence of WNV in the UK equine population to determine the extent of vaccination or to provide evidence of recent infection. Methods Equine serum samples were obtained from the Animal and Plant Health Agency’s equine testing service between August and November 2019. A total of 988 serum samples were selected for horses resident in South East England. WNV seroprevalence was determined using two enzyme-linked immunosorbent assays (ELISAs) to detect total flavivirus antibodies and WNV-specific immunoglobulin M (IgM) antibodies. Positive IgM results were investigated by contacting the submitting veterinarian to establish the clinical history or evidence of prior vaccination of the horses in question. Results Within the cohort, 274 samples tested positive for flavivirus antibodies, of which two subsequently tested positive for WNV-specific IgM antibodies. The follow-up investigation established that both horses had been vaccinated prior to serum samples being drawn, which resulted in an IgM-positive response. All the samples that tested positive by competition ELISA were from horses set to be exported to countries where WNV is endemic. Consequently, the positive results were likely due to previous vaccination. In contrast, 714 samples were seronegative, indicating that the majority of the UK equine population may be susceptible to WNV infection. Conclusions There was no evidence for cryptic WNV infection in a cohort of horses sampled in England in 2019. All IgM-seropositive cases were due to vaccination; this should be noted for future epidemiological surveys in the event of a disease outbreak, as it is not possible to distinguish vaccinated from infected horses without knowledge of their clinical histories.

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Seroprevalence of West Nile virus in horses in different Moroccan regions

Cited by 23 publications

References 24 publications

Evidence of circulation of West Nile virus in Culex pipiens mosquitoes and horses in Morocco

Evidence of circulation of West Nile virus in Culex pipiens mosquitoes and horses in Morocco

The Recent Update of the Situation of West Nile Fever among Equids in Egypt after Three Decades of Missing Information

Equine seroprevalence of West Nile virus antibodies in the UK in 2019

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