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Renaud Lancelot - One of the best experts on this subject based on the ideXlab platform.
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Mapping the serological prevalence rate of west Nile fever in Equids, Tunisia
Transboundary and emerging diseases, 2015Co-Authors: Ramzi Bargaoui, Sylvie Lecollinet, Renaud LancelotAbstract:West Nile fever (WNF) is a viral disease of wild birds transmitted by mosquitoes. Humans and Equids can also be affected and suffer from meningoencephalitis. In Tunisia, two outbreaks of WNF occurred in humans in 1997 and 2003; sporadic cases were reported on several other years. Small-scale serological surveys revealed the presence of antibodies against WN virus (WNV) in Equid sera. However, clinical cases were never reported in Equids, although their population is abundant in Tunisia. This study was achieved to characterize the nationwide serological status of WNV in Tunisian Equids. In total, 1189 sera were collected in 2009 during a cross-sectional survey. Sera were tested for IgG antibodies, using ELISA and microneutralization tests. The estimated overall seroprevalence rate was 28%, 95% confidence interval [22; 34]. The highest rates were observed (i) in the north-eastern governorates (Jendouba, 74%), (ii) on the eastern coast (Monastir, 64%) and (iii) in the lowlands of Chott El Jerid and Chott el Gharsa (Kebili, 58%; Tozeur, 52%). Environmental risk factors were assessed, including various indicators of wetlands, wild avifauna, night temperature and chlorophyllous activity (normalized difference vegetation index: NDVI). Multimodel inference showed that lower distance to ornithological sites and wetlands, lower night-time temperature, and higher NDVI in late spring and late fall were associated with higher serological prevalence rate. The model-predicted nationwide map of WNF seroprevalence rate in Tunisian Equids highlighted different areas with high seroprevalence probability. These findings are discussed in the perspective of implementing a better WNF surveillance system in Tunisia. This system might rely on (i) a longitudinal survey of sentinel birds in high-risk areas and time periods for WNV transmission, (ii) investigations of bird die-offs and (iii) syndromic surveillance of equine meningoencephalitis.
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Mapping the Serological Prevalence Rate of West Nile fever in Equids, Tunisia
Transboundary and emerging diseases, 2013Co-Authors: Ramzi Bargaoui, Sylvie Lecollinet, Renaud LancelotAbstract:West Nile fever (WNF) is a viral disease of wild birds transmitted by mosquitoes. Humans and Equids can also be affected and suffer from meningoencephalitis. In Tunisia, two outbreaks of WNF occurred in humans in 1997 and 2003; sporadic cases were reported on several other years. Small-scale serological surveys revealed the presence of antibodies against WN virus (WNV) in Equid sera. However, clinical cases were never reported in Equids, although their population is abundant in Tunisia. This study was achieved to characterize the nationwide serological status of WNV in Tunisian Equids. In total, 1189 sera were collected in 2009 during a cross-sectional survey. Sera were tested for IgG antibodies, using ELISA and microneutralization tests. The estimated overall seroprevalence rate was 28%, 95% confidence interval [22; 34]. The highest rates were observed (i) in the north-eastern governorates (Jendouba, 74%), (ii) on the eastern coast (Monastir, 64%) and (iii) in the lowlands of Chott El Jerid and Chott el Gharsa (Kebili, 58%; Tozeur, 52%). Environmental risk factors were assessed, including various indicators of wetlands, wild avifauna, night temperature and chlorophyllous activity (normalized difference vegetation index: NDVI). Multimodel inference showed that lower distance to ornithological sites and wetlands, lower night-time temperature, and higher NDVI in late spring and late fall were associated with higher serological prevalence rate. The model-predicted nationwide map of WNF seroprevalence rate in Tunisian Equids highlighted different areas with high seroprevalence probability. These findings are discussed in the perspective of implementing a better WNF surveillance system in Tunisia. This system might rely on (i) a longitudinal survey of sentinel birds in high-risk areas and time periods for WNV transmission, (ii) investigations of bird die-offs and (iii) syndromic surveillance of equine meningoencephalitis. (Resume d'auteur)
Sanjay Kumar - One of the best experts on this subject based on the ideXlab platform.
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Seroprevalence and Risk Factor Associated with Endemicity of Theileria equi Infection in Horses in Rajasthan State, India
Indian Journal of Animal Research, 2021Co-Authors: Rakesh J. Bhojani, Rajender Kumar, Anju Chahar, Vikram S. Dewal, Kruti D. Mandal, Sneh L. Chauhan, Yash Pal, Sanjay KumarAbstract:Background: Equine piroplasmosis is a haemoprtozoan disease of Equids and enzootic in Rajasthan prefecture of India. In endemic areas, the subclinical condition is more common, as infected Equids recover from the disease and become latently infected. This study aimed to investigate the seroepidemiology and risk factors associated with the endemicity of Theileria equi infection in Rajasthan state. Methods: A cross-sectional study on the seroprevalence of Theileria equi, was performed. Total of 151 serum samples collected from different areas of Rajasthan. The serum samples were screened by ELISA for assessment of seroprevalence of T. equi infection.Result: Overall seroprevalence of T. equi was 49.66%. A total of 75 T. equi seropositive horses were detected and one horse was clinically positive for T. equi infection. The clinical signs observed were - fever, haemoglobinuria, mild colic, anaemia and icteric conjunctival mucous membrane. Theileria equi infection is endemic among horses in Rajasthan state and Ajmer district found the most endemic. Haematological observations in T. equi clinically infected and healthy horses were studies. A decreased haemoglobin concentration, packed cell volume, total erythrocytic counts were observed in T. equi infected horse in comparison to healthy horses. This observation showed anaemic condition in T. equi clinically infected equine. An increased concentration of liver enzymes – AST, ALP, GGT in T. equi infected equine was also recorded, which indicated the liver damage.
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risk factor analysis associated with theileria equi infected equines in semi arid and sub humid ecological enzootic zones of india
Veterinary Parasitology: Regional Studies and Reports, 2018Co-Authors: Rajender Kumar, Yash Pal, Rajesh K Dahiya, Raj Kumar Salar, Kruti Debnath Mandal, B N Tripathi, Sanjay KumarAbstract:Equine piroplasmosis is a haemoprtozoan disease of equines and enzootic in tropical and subtropical countries. A cross-sectional study on sero-prevalence of Theileria equi, the causative agent of EP, was performed in semi-arid and sub-humid ecological endemic zones of India including Rajasthan, Haryana and Gujarat states, in order to evaluate the enzootic status/level of exposure to equine population due to this infection and addressed associated risk factors. Serum samples were collected from a total of 1021 Equids that comprised of 792 horses, 168 donkeys and 61 mules and evaluated for T. equi specific antibodies in equine merozoite antigen-2 (EMA-2) based on indirect ELISA. The state with high sero-prevalence rate was Rajasthan (71.40%), followed by Haryana (60.39%) and Gujarat (48.92%). Overall T. equi sero-positivity in equines was 64.44%. Species-wise T. equi sero-prevalence was 66.29%, 51.19% and 91.80% in horses, donkeys and mules respectively. The association and risk factor among age, gender and species in relation with T. equi infection was statistically analyzed at 95% level of significance (p<0.05). A very high T. equi sero-positivity was recorded in 0-1year age group of equines (60%), indicating that this naive age group contacts with T. equi infected ticks and remains infected throughout its lifetime. The sero-prevalence rate was significantly associated with the species of animal (p<0.05). The risk factor analysis kept mules at higher risk (Odd's ratio; 5.696; 95% confidence interval: 2.25-14.38) of getting infection as compared to horses and donkeys. This study has demonstrated high enzootic nature of T. equi infection in semi-arid and sub-humid ecological zones of India. Mules, in comparison to horses and donkeys were found at higher risk of getting T. equi infection, indicating that disease prevalence is associated with species of the infected host.
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spatial distribution risk factors and haemato biochemical alterations associated with theileria equi infected Equids of punjab india diagnosed by indirect elisa and nested pcr
Acta Tropica, 2016Co-Authors: Deepak Sumbria, Sanjay Kumar, Amrita Sharma, L. D. Singla, Rajesh K Dahiya, Raj SetiaAbstract:Equine piroplasmosis is a febrile, tick-borne disease of Equids predominately caused by obligatory intra-erythrocytic protozoa Theileria equi in the Indian sub-continent. A cross-sectional study was carried out on 464 Equids (426 horses and 38 donkeys/mules) in Punjab, India to assess the level of exposure to equine piroplasmosis by 18S rRNA gene nested polymerase chain reaction (nPCR) and equine merozoite antigen-2 (EMA2) indirect-ELISA (enzyme linked immunosorbent assay), to investigate risk factors and haemato-biochemical alterations associated with the infection. The endemicity of the disease was confirmed by positive PCR amplification in 21.77% and positive antibody titers in 49.78% Equid samples. There was a fair agreement between these two diagnostic techniques (Kappa coefficient=0.326). The spatial distribution analysis revealed an increasing trend of T. equi prevalence from north-eastern to south-western region of Punjab by both the techniques correspondingly, which proffered a direct relation with temperature and inverse with humidity variables. The relatively prominent risk factor associated with sero-positivity was the presence of other domestic animals in the herd, while the propensity of finding a positive PCR amplification was higher in donkeys/mules, animal kept at unorganised farm or those used for commercial purposes as compared to their counterparts. There was a significant increase in globulins, gamma glutamyl-transferase, total bilirubin, direct bilirubin, indirect bilirubin, glucose levels and decrease in total erythrocyte count, haemoglobin, packed cell volume by animals, which were revealed positive by nPCR (may or may not positive by indirect-ELISA) and increase in creatinine, total bilirubin, direct bilirubin, glucose and decrease in total erythrocytes count by animals, which were revealed positive by indirect-ELISA (alone). To our knowledge, this study, for the first time, brings out a comprehensive report on the status on spatial distribution of T. equi in Punjab (India) state, thoroughly investigated by molecular and serological techniques, evaluating various environmental and demographic risk factors along with the haemato-biochemical alterations in the exposed animals.
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multiplex pcr for detection of trypanosoma evansi and theileria equi in Equids of punjab india
Veterinary Parasitology, 2015Co-Authors: Deepak Sumbria, Amrita Sharma, L. D. Singla, Mandeep Singh Bal, Sanjay KumarAbstract:Abstract Multiplex PCR for simultaneous detection of Trypanosoma evansi and Theileria equi in single-step reaction was optimized and employed on 108 Equids (99 horses and 9 donkeys/mules) blood samples collected from two agro-climatic zones (Sub-mountain undulating zone and Undulating plain zone) of Punjab to evaluate the status of concurrent infection and associated risk factors. The amplification products of 257 and 709 bp targeting repetitive nucleotide sequence of variable surface glycoproteins of T. evansi and 18S rRNA gene of T. equi, respectively expressed high fidelity of the primer pairs with sequence homology to neighboring geographic isolates. The overall prevalence of T. evansi and T. equi was 3.7 and 1.85%, with Undulating plain zone at higher infection risk for T. equi (OR = 3.24, 95% CI = 0.28–83.65); and Sub-mountain undulating zone (OR = ∞, 95% CI = 0.25–∞) for T. evansi. Multiplex PCR revealed higher risk of infection of both T. equi (OR = 6.75, 95% CI = 0.58–175.38) and T. evansi (OR = 2.11, 95% CI = 0.05–80.36) in the farms with inappropriate management system. The risk factor associated with the type of host species had an odds ratio of 12.35 (95% CI = 0.29–508.37) for donkeys/mules versus horses for T. evansi infection. This group was also at higher risk of infection with Odds ratio (OR) of 4 (95% CI = 0.14–53.99) for T. equi. The current investigation brings out various commodities at risk of infection pertaining to Equid trypanosomosis and theileriosis evaluated by a rapid and sensitive multiplex PCR assay.
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theileria equi merozoite antigen 2 interacts with actin molecule of equine erythrocyte during their asexual development
Experimental Parasitology, 2012Co-Authors: Sanjay Kumar, Noboru Inoue, Ikuo Igarashi, Chihiro Sugimoto, Naoaki Yokoyama, Xuenan Xuan, Jungyeon Kim, Sabine BorkmimmAbstract:Theileria equi is a tick-transmitted intraerythrocytic protozoan parasite in Equids. Equine merozoite antigen (EMA)-1 and EMA-2 of T. equi have been identified as immunodominant proteins co-expressed on the surface of extra-erythrocytic merozoites. Additionally, only the EMA-2 is shed into the cytoplasm of infected erythrocyte or inside the erythrocytic membrane during their early developmental stage. In this study, we initially performed West-Western blot analysis on Triton X-100-insoluble erythrocytic skeleton collected from a healthy horse, using a glutathione S-transferase (GST)-tagged recombinant EMA-1t or EMA-2t of T. equi. The results indicated positive interactions of actin and band 4.1 molecules in the equine erythrocytic skeleton only with the recombinant EMA-2t. Subsequently, we carried out GST pull-down assay using the recombinant antigens (as above) against solubilized lysate of equine erythrocytic skeleton, and confirmed the co-precipitation of actin molecule with EMA-2t, but not with the EMA-1t. The interaction of EMA-2 with host erythrocytic actin indicated its role in the pathobiology of T. equi infection within host erythrocytes.
F.j. López-cachero - One of the best experts on this subject based on the ideXlab platform.
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Equid use and provision during the Early Iron Age in Can Roqueta (NE Iberian Peninsula). Zooarchaeological study and first strontium isotope result (87Sr/86Sr)
Journal of Archaeological Science: Reports, 2019Co-Authors: S. Albizuri, S. Valenzuela-lamas, Delphine Bosch, M. Fernandez, F.j. López-cacheroAbstract:This article reports the results of a zooarchaeological study (including, mortality profiles, and anatomical and pathological descriptions) of the Early Iron Age (8th-6th c. BCE) Equid remains at the Can Roqueta site (Sabadell, Barcelona), together with the first strontium isotope results to determine their geographical origin. The zooarchaeological study reveals a remarkable number of Equid remains at the site, the bone pathologies of which suggest their use for riding, drafting and load carrying. The mortality and sex profiles point to the presence of adult animals, while the absence of neonatal and juvenile remains raises the question as to whether these individuals may have originated from other sites specialised in Equid breeding. The strontium values obtained from six individuals suggest that some Equids were reared in a geological area with a similar strontium signature to that of the Vallès area, where the site is located. However, three Equids present a different strontium signature, pointing to a possibly different geographical origin.
Deepak Sumbria - One of the best experts on this subject based on the ideXlab platform.
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molecular survey in relation to risk factors and haemato biochemical alteration in theileria equi infection of equines in punjab province india
Veterinary Parasitology: Regional Studies and Reports, 2017Co-Authors: Deepak Sumbria, Amrita Sharma, L. D. Singla, Mandeep Singh Bal, C S RandhawaAbstract:Equine piroplasmosis caused by Theileria equi, an apicomplexan intracellular haemoprotozoan parasite effects Equids throughout the world. Current investigation is the first detailed epidemiological survey report based on conventional (blood smear) and primary polymerase chain reaction (PCR) for the detection of T. equi on 464 Equids (426 horses and 38 donkeys/mules) in Punjab province of India. PCR targeting 18S rRNA gene of T. equi produced high fidelity 709bp amplification products with 100% concordance with blood films. The prevalence of infection was proportional (P≤0.01) to temperature and aridness of the regions, which turned out to be the most important physical factor pertaining to T. equi infection. Spatial distribution analysis revealed an increasing trend of disease prevalence from north-eastern to south-western region of Punjab by both the techniques. Haemato-biochemical analysis revealed significant decrease in total erythrocyte count and haemoglobin; and increase in mean corpuscular haemoglobin, serum globulin, glucose, creatinine, aspartate aminotransferase and bilirubin levels (P≤0.05). This study divulges the endemicity of equine theileriosis in Punjab with the prominence of various odds of infection, emphasising the pathophysiological manifestation associated with latent infection of T. equi detectable by PCR.
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spatial distribution risk factors and haemato biochemical alterations associated with theileria equi infected Equids of punjab india diagnosed by indirect elisa and nested pcr
Acta Tropica, 2016Co-Authors: Deepak Sumbria, Sanjay Kumar, Amrita Sharma, L. D. Singla, Rajesh K Dahiya, Raj SetiaAbstract:Equine piroplasmosis is a febrile, tick-borne disease of Equids predominately caused by obligatory intra-erythrocytic protozoa Theileria equi in the Indian sub-continent. A cross-sectional study was carried out on 464 Equids (426 horses and 38 donkeys/mules) in Punjab, India to assess the level of exposure to equine piroplasmosis by 18S rRNA gene nested polymerase chain reaction (nPCR) and equine merozoite antigen-2 (EMA2) indirect-ELISA (enzyme linked immunosorbent assay), to investigate risk factors and haemato-biochemical alterations associated with the infection. The endemicity of the disease was confirmed by positive PCR amplification in 21.77% and positive antibody titers in 49.78% Equid samples. There was a fair agreement between these two diagnostic techniques (Kappa coefficient=0.326). The spatial distribution analysis revealed an increasing trend of T. equi prevalence from north-eastern to south-western region of Punjab by both the techniques correspondingly, which proffered a direct relation with temperature and inverse with humidity variables. The relatively prominent risk factor associated with sero-positivity was the presence of other domestic animals in the herd, while the propensity of finding a positive PCR amplification was higher in donkeys/mules, animal kept at unorganised farm or those used for commercial purposes as compared to their counterparts. There was a significant increase in globulins, gamma glutamyl-transferase, total bilirubin, direct bilirubin, indirect bilirubin, glucose levels and decrease in total erythrocyte count, haemoglobin, packed cell volume by animals, which were revealed positive by nPCR (may or may not positive by indirect-ELISA) and increase in creatinine, total bilirubin, direct bilirubin, glucose and decrease in total erythrocytes count by animals, which were revealed positive by indirect-ELISA (alone). To our knowledge, this study, for the first time, brings out a comprehensive report on the status on spatial distribution of T. equi in Punjab (India) state, thoroughly investigated by molecular and serological techniques, evaluating various environmental and demographic risk factors along with the haemato-biochemical alterations in the exposed animals.
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Theileria equi and Babesia caballi infection of Equids in Punjab, India: a serological and molecular survey
Tropical Animal Health and Production, 2016Co-Authors: Deepak Sumbria, Lachhman Das Singla, Amrita SharmaAbstract:A cross-sectional study was conducted in Submountain undulating, Undulating plain, Western and Western plain agro-climatic zones of Punjab province, India, to determine the prevalence, agreement between diagnostic tests and associated related risk factors of Theileria equi and Babesia caballi infection in Equids (horses, donkey, mules). An overall prevalence of 14.14 and 0.0 % of T. equi and B. caballi was recorded by multiplex polymerase chain reaction targeting 18S ribosomal RNA (rRNA) for both the parasites and 75 and 1.11 % by competitive enzyme-linked immunosorbent assay in a representative sample of 180 animals. Only two animals with positive antibody titre from B. caballi and none with PCR indicated T. equi as the predominant haemoprotozoan responsible for equine piroplasmosis in the study area. Among the PCR-positive animals, presence of tick vectors in farm vicinity was the most influential associated with T. equi infection ( P = 0.002; odds ratio (OR) 9.30; 95 % confidence interval (CI) = 3.32–27.10). For animals with higher anti- T. equi antibody titres, strong association of sero-prevalence for T. equi was recorded with age, sex, usage, tick infestation and deworming/vaccination status of host animals and farm management strategies. The study has demonstrated the possible absence of B. caballi in both conducive and non-conducive areas of Punjab and demonstrated T. equi as the potential agent of equine piroplasmosis in Punjab.
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multiplex pcr for detection of trypanosoma evansi and theileria equi in Equids of punjab india
Veterinary Parasitology, 2015Co-Authors: Deepak Sumbria, Amrita Sharma, L. D. Singla, Mandeep Singh Bal, Sanjay KumarAbstract:Abstract Multiplex PCR for simultaneous detection of Trypanosoma evansi and Theileria equi in single-step reaction was optimized and employed on 108 Equids (99 horses and 9 donkeys/mules) blood samples collected from two agro-climatic zones (Sub-mountain undulating zone and Undulating plain zone) of Punjab to evaluate the status of concurrent infection and associated risk factors. The amplification products of 257 and 709 bp targeting repetitive nucleotide sequence of variable surface glycoproteins of T. evansi and 18S rRNA gene of T. equi, respectively expressed high fidelity of the primer pairs with sequence homology to neighboring geographic isolates. The overall prevalence of T. evansi and T. equi was 3.7 and 1.85%, with Undulating plain zone at higher infection risk for T. equi (OR = 3.24, 95% CI = 0.28–83.65); and Sub-mountain undulating zone (OR = ∞, 95% CI = 0.25–∞) for T. evansi. Multiplex PCR revealed higher risk of infection of both T. equi (OR = 6.75, 95% CI = 0.58–175.38) and T. evansi (OR = 2.11, 95% CI = 0.05–80.36) in the farms with inappropriate management system. The risk factor associated with the type of host species had an odds ratio of 12.35 (95% CI = 0.29–508.37) for donkeys/mules versus horses for T. evansi infection. This group was also at higher risk of infection with Odds ratio (OR) of 4 (95% CI = 0.14–53.99) for T. equi. The current investigation brings out various commodities at risk of infection pertaining to Equid trypanosomosis and theileriosis evaluated by a rapid and sensitive multiplex PCR assay.
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equine piroplasmosis current status
2014Co-Authors: Deepak Sumbria, Aman Dev Moudgil, L. D. SinglaAbstract:Equine piroplasmosis (EP) caused by apicomplexan haemoprotozoan parasites , Babesia caballi and Theileria equi poses a threat to intercontinental maneuver of Equids. It is diff used by infected ixodid ticks, contaminated blood s ources needlesand also by transplacental route. For potent chemotherapy to be effective, timely confirmation is required along w ith a swift test to provide an early diagnosis . Affirmation of EP in blood smear or by in vitro technique is an utter method of confirmation, but f or this well-furnished laboratory, experienced person and more time is required. So, many different serodiagno stic tests such as the complement fixation test (CFT), indirect fluorescen t antibody test (IFAT), enzyme linked immuneosorbent assay (ELISA) has been recommended for detecting the presence of anti bodies to Babesia spp. These have several disadvantages, including lo w sensitivity for detecting latent infections and fal se-positive results. To increase sensitivity and di fferentiate between current and past infection ELISA may be an alternative, but its main demerit is its poor specificity and limited a ntigen supply. Now a day’s more specific and accurate techniques are available for the direct detection of the parasites, i.e. Po lymerase chain reaction (PCR) targeting different genes of DNA probes. Since ther e is no vaccine available for EP, thus, the control must include effective tick control, serological, molecular monitoring of Equid s and the application of antiprotozoal drugs.
Ramzi Bargaoui - One of the best experts on this subject based on the ideXlab platform.
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Mapping the serological prevalence rate of west Nile fever in Equids, Tunisia
Transboundary and emerging diseases, 2015Co-Authors: Ramzi Bargaoui, Sylvie Lecollinet, Renaud LancelotAbstract:West Nile fever (WNF) is a viral disease of wild birds transmitted by mosquitoes. Humans and Equids can also be affected and suffer from meningoencephalitis. In Tunisia, two outbreaks of WNF occurred in humans in 1997 and 2003; sporadic cases were reported on several other years. Small-scale serological surveys revealed the presence of antibodies against WN virus (WNV) in Equid sera. However, clinical cases were never reported in Equids, although their population is abundant in Tunisia. This study was achieved to characterize the nationwide serological status of WNV in Tunisian Equids. In total, 1189 sera were collected in 2009 during a cross-sectional survey. Sera were tested for IgG antibodies, using ELISA and microneutralization tests. The estimated overall seroprevalence rate was 28%, 95% confidence interval [22; 34]. The highest rates were observed (i) in the north-eastern governorates (Jendouba, 74%), (ii) on the eastern coast (Monastir, 64%) and (iii) in the lowlands of Chott El Jerid and Chott el Gharsa (Kebili, 58%; Tozeur, 52%). Environmental risk factors were assessed, including various indicators of wetlands, wild avifauna, night temperature and chlorophyllous activity (normalized difference vegetation index: NDVI). Multimodel inference showed that lower distance to ornithological sites and wetlands, lower night-time temperature, and higher NDVI in late spring and late fall were associated with higher serological prevalence rate. The model-predicted nationwide map of WNF seroprevalence rate in Tunisian Equids highlighted different areas with high seroprevalence probability. These findings are discussed in the perspective of implementing a better WNF surveillance system in Tunisia. This system might rely on (i) a longitudinal survey of sentinel birds in high-risk areas and time periods for WNV transmission, (ii) investigations of bird die-offs and (iii) syndromic surveillance of equine meningoencephalitis.
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Mapping the Serological Prevalence Rate of West Nile fever in Equids, Tunisia
Transboundary and emerging diseases, 2013Co-Authors: Ramzi Bargaoui, Sylvie Lecollinet, Renaud LancelotAbstract:West Nile fever (WNF) is a viral disease of wild birds transmitted by mosquitoes. Humans and Equids can also be affected and suffer from meningoencephalitis. In Tunisia, two outbreaks of WNF occurred in humans in 1997 and 2003; sporadic cases were reported on several other years. Small-scale serological surveys revealed the presence of antibodies against WN virus (WNV) in Equid sera. However, clinical cases were never reported in Equids, although their population is abundant in Tunisia. This study was achieved to characterize the nationwide serological status of WNV in Tunisian Equids. In total, 1189 sera were collected in 2009 during a cross-sectional survey. Sera were tested for IgG antibodies, using ELISA and microneutralization tests. The estimated overall seroprevalence rate was 28%, 95% confidence interval [22; 34]. The highest rates were observed (i) in the north-eastern governorates (Jendouba, 74%), (ii) on the eastern coast (Monastir, 64%) and (iii) in the lowlands of Chott El Jerid and Chott el Gharsa (Kebili, 58%; Tozeur, 52%). Environmental risk factors were assessed, including various indicators of wetlands, wild avifauna, night temperature and chlorophyllous activity (normalized difference vegetation index: NDVI). Multimodel inference showed that lower distance to ornithological sites and wetlands, lower night-time temperature, and higher NDVI in late spring and late fall were associated with higher serological prevalence rate. The model-predicted nationwide map of WNF seroprevalence rate in Tunisian Equids highlighted different areas with high seroprevalence probability. These findings are discussed in the perspective of implementing a better WNF surveillance system in Tunisia. This system might rely on (i) a longitudinal survey of sentinel birds in high-risk areas and time periods for WNV transmission, (ii) investigations of bird die-offs and (iii) syndromic surveillance of equine meningoencephalitis. (Resume d'auteur)