SEARCH · Search PubMed

Results for “Seroepidemiology”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

15 recordsLinked to original sources

PubMed2026

Toxoplasma gondii IgG seroprevalence in Mauritanian dromedary camels: First multi-regional survey.

Toxoplasma gondii is a globally distributed zoonotic parasite, and dromedary camels are important intermediate hosts in arid and semi-arid regions. However, information on T. gondii exposure in camels is lacking in Mauritania, which harbors one of the largest camel populations in West Africa. This study reports the first multi-regional seroepidemiological survey to estimate T. gondii seroprevalence and identify associated risk factors in Mauritanian dromedaries. Between 2023 and 2024, serum samples were collected from 953 camels across eight climatically distinct regions. Anti-T. gondii IgG antibodies were detected using the Modified Agglutination Test (MAT; cutoff≥1:20). Risk factors investigated included geographical region, sex, age group, and season of sampling, using multivariable logistic regression and a mixed-effects linear probability model accounting for regional clustering. The overall seroprevalence was 15.0% (143/953). Exposure varied markedly across regions, ranging from 0% in the hyper-arid northern regions of Adrar and Tagant to 41.7% in the southern Sahelian region of Guidimakha. This pronounced spatial gradient is consistent with contrasting climatic and ecological conditions, as higher rainfall and humidity in the south are hypothesized to favor environmental oocyst survival compared to the extreme aridity of the north. Geographical region and age were independent predictors of seropositivity. Compared with camels from Nouakchott, those from Guidimakha had higher odds of exposure (aOR = 2.63), whereas camels from Trarza had a markedly lower risk (aOR = 0.09). Camels older than 6 years were more than twice as likely to be seropositive as those aged 3-5 years, whereas sex and season were not associated with seropositivity. These findings indicate that T. gondii exposure is widespread in Mauritanian dromedaries and that ecological conditions may influence exposure patterns. The marked spatial heterogeneity supports targeted surveillance and One Health interventions to reduce the potential zoonotic risk associated with camel-derived food products.

Animals↗

PubMed2024

Identification and epidemiological study of an uncultured flavivirus from ticks using viral metagenomics and pseudoinfectious viral particles.

During their blood-feeding process, ticks are known to transmit various viruses to vertebrates, including humans. Recent viral metagenomic analyses using next-generation sequencing (NGS) have revealed that blood-feeding arthropods like ticks harbor a large diversity of viruses. However, many of these viruses have not been isolated or cultured, and their basic characteristics remain unknown. This study aimed to present the identification of a difficult-to-culture virus in ticks using NGS and to understand its epidemic dynamics using molecular biology techniques. During routine tick-borne virus surveillance in Japan, an unknown flaviviral sequence was detected via virome analysis of host-questing ticks. Similar viral sequences have been detected in the sera of sika deer and wild boars in Japan, and this virus was tentatively named the Saruyama virus (SAYAV). Because SAYAV did not propagate in any cultured cells tested, single-round infectious virus particles (SRIP) were generated based on its structural protein gene sequence utilizing a yellow fever virus-based replicon system to understand its nationwide endemic status. Seroepidemiological studies using SRIP as antigens have demonstrated the presence of neutralizing antibodies against SAYAV in sika deer and wild boar captured at several locations in Japan, suggesting that SAYAV is endemic throughout Japan. Phylogenetic analyses have revealed that SAYAV forms a sister clade with the Orthoflavivirus genus, which includes important mosquito- and tick-borne pathogenic viruses. This shows that SAYAV evolved into a lineage independent of the known orthoflaviviruses. This study demonstrates a unique approach for understanding the epidemiology of uncultured viruses by combining viral metagenomics and pseudoinfectious viral particles.

Animals↗

PubMed2026

Does Toxoplasma gondii infection have a causal impact on human psychopathology? A Mendelian randomization analysis.

Toxoplasma gondii (T. gondii) is a prevalent zoonotic parasite that has been implicated in influencing human psychiatric disorders and risk-taking behaviors. Using genome-wide association study (GWAS) data, we selected 25 and 76 single-nucleotide polymorphisms as instrumental variables for anti-T. gondii IgG seropositivity and anti-T. gondii IgG levels, respectively, and conducted two-sample Mendelian randomization (MR) analyses across 18 GWAS datasets to investigate potential causal effects on addiction, bipolar disorder, obsessive-compulsive disorder, schizophrenia, and risk-taking behavior in European populations. Contrary to previous epidemiological evidence, our MR analyses do not support a significant causal association between T. gondii infection and any of the studied psychiatric disorders or risk-taking behavior. Collectively, these results establish that any true causal effect of genetic liability to T. gondii infection is likely to be small (OR < 1.18 for schizophrenia, < 1.29 for bipolar disorder) and below the effect sizes typically reported in observational seroepidemiological studies, although small or infection-phase-specific effects cannot be excluded.

Humans↗

PubMed2025

Integrated Seroprevalence and Genome-Based Study of SARS-CoV-2 Viral Strains in N'Djamena: Insights Into Chad's COVID-19 Epicenter.

The COVID-19 epidemic has shown regional variations in transmission and outcomes. As a primary hotspot in Chad, N'Djamena is crucial for comprehensive epidemiological investigation. Our study employed two methodologies: seroprevalence data collection and whole-genome sequencing of SARS-CoV-2 strains. This dual approach assessed population exposure and virus genetic diversity. Seroprevalence data indicated broader exposure than confirmed cases suggested, and genome sequencing identified multiple strains, including globally recognized variants of concern. Integrating these data provided insights into transmission dynamics, potential herd immunity thresholds, and the impact of specific variants on disease progression. Our findings underscore the importance of integrated, multidisciplinary research in infectious disease epidemiology and inform targeted public health strategies, including social measures and vaccination, to combat infectious diseases in N'Djamena.

Humans↗

PubMed2025

Seroprevalence of Chikungunya and O'nyong-nyong Viruses in Senegal, West Africa.

Arthritogenic alphaviruses such as chikungunya (CHIKV) and o'nyong-nyong (ONNV) viruses have shown capacity to cause widespread epidemics, with recurrent and sporadic outbreaks occurring throughout sub-Saharan Africa. We analyzed the seroprevalence for CHIKV and ONNV in 470 non-febrile subjects from three regions in Senegal (Sindia, 2018; Thies, 2018; and Kedougou, 2022/2023) using retrospective samples. We assessed the presence of anti-CHIKV IgG and neutralizing antibody titers against CHIKV and ONNV via enzyme-linked immunosorbent assay (ELISA) and microneutralization tests, respectively, and determined risk factors of CHIKV and ONNV exposure by binary logistic regression. The overall alphavirus seroprevalence based on an anti-CHIKV virus like particle (VLP) IgG ELISA was 38.5%, with rates varying geographically: Kedougou (48.6%), Thies (31.9%), and Sindia (14.9%). Neutralizing antibody titers revealed CHIKV and ONNV seroprevalence rates of 7.4% and 9.8%, respectively, with significant variations by region and age group. Cross-reactivity analysis showed that 82.9% of CHIKV cases exhibited a neutralizing response to ONNV, while 71.7% of ONNV cases cross-neutralized CHIKV. Residents of Thies had significantly higher odds of CHIKV infection (aOR, 3.147; 95% CI: 1.164-8.510) while ONNV infection was more likely in Kedougou (aOR, 3.888; 95% CI: 1.319-11.466). Furthermore, older age (> 40 years) was a significant risk factor both CHIKV (aOR, 2.094; 95% CI: 0.846-5.185) and ONNV infection (aOR, 2.745; 95% CI: 1.212-6.216). Our study confirms the co-circulation of CHIKV and ONNV in Senegal, highlighting their geographic and demographic distribution. These findings underscore the need for continued surveillance, alphavirus testing, and tailored public health strategies to mitigate their impact in Senegal.

Humans↗

PubMed2025

Seropositivity to Dengue, Zika, Yellow Fever, and West Nile Viruses in Senegal, West Africa.

West Africa serves as a critical region for the co-circulation of mosquito-borne flaviviruses, which often precipitate sporadic outbreaks. This study investigated the seropositivity to dengue virus serotypes 1-4 (DENV-1-4), Zika virus (ZIKV), yellow fever virus (YFV), and West Nile virus (WNV) in three regions of Senegal: Sindia, Thies, and Kedougou. We retrospectively analyzed 470 serum samples for flavivirus immunoglobulin G (IgG) using a DENV-2 envelope (E) ELISA. Our findings revealed an overall flavivirus seroprevalence of 37.23%. Among the DENV-2 E IgG positive samples, the proportion of subjects with IgG to DENV-1-4, ZIKV, YFV, or WNV NS1 was 57.14%, 12.57%, 80.57%, and 17.14%, respectively, with 66.86% harboring neutralizing antibodies against two or more flaviviruses. We also identified that residents in Sindia (ZIKV, aOR, 9.428; 95% CI: 1.882-47.223 and WNV, aOR, 6.039; 95% CI: 1.855-19.658) and Kedougou (ZIKV, aOR, 7.487; 95% CI: 1.658-33.808 and WNV, aOR, 1.142; 95% CI: 0.412-3.164) were at significant risk for ZIKV and WNV exposure. This study underscores the complexity of flavivirus epidemiology in West Africa and the necessity for enhanced surveillance to inform public health strategies.

Humans↗

PubMed2026

Epidemiological status of bovine viral diarrhea virus in water buffalo (Bubalus bubalis): A global systematic review and meta-analysis.

Bovine viral diarrhea virus (BVDV) remains a neglected viral disease in water buffalo despite its significant economic impact in production systems. Although limited epidemiological studies have been reported worldwide, the serostatus and active infection in buffalo have not been systematically reviewed. A systematic review and meta-analysis were conducted to estimate BVDV prevalence in water buffalo and identify associated epidemiological factors. Relevant studies published up to January 31, 2026, were retrieved from five electronic databases. A total of 49 studies were identified from 15 different countries were found for inclusion. A random-effects model was used to estimate pooled-prevalence and assess heterogeneity among studies. A meta-analysis of 37 studies (9270 buffalo) estimated a pooled BVDV seroprevalence of 30.5%, while analysis of 16 studies (7189 animals) indicated an antigen prevalence of 16.5%. Continent-wise analysis revealed the highest BVDV seroprevalence in South-America (44.0%), while antigen prevalence was highest in Africa (21.2%) followed by Asia at 12.2%, and no BVDV data reported from North-America. Among the different countries, the highest BVDV seroprevalence was detected in Turkey (61.6%) and Argentina (59.0%), while antigen prevalence was highest in Egypt (21.2%), with lower estimates in Brazil (11.8%) and Iraq (11.3%). Notably, high heterogeneity (I2 > 90%) was observed in the all-pooled estimates, indicating variations in sampling period, age, sex, sample source and types, diagnostic methods, production-system, and study quality. These findings demonstrate the widespread presence of BVDV in water buffalo populations and indicate the need for targeted control strategies to mitigate its impact on health and productivity.

Animals↗

PubMed2026

A systematic review and meta-analysis to estimate the global prevalence of leptospirosis in sheep.

Leptospirosis in sheep is a zoonotic concern considering sheep may act as potential reservoirs for Leptospira spp. infection to humans. This study aimed to estimate the pooled prevalence of leptospirosis in sheep worldwide. A comprehensive literature search was conducted across databases following PRISMA guidelines. Meta-analyses were performed using a random effect model in R software (version 4.3.1) to calculate pooled prevalence with 95% confidence intervals (CI). Subgroup analyses were performed based on prevalence types, diagnostic methods and continental regions to explore sources of heterogeneity. A total of 138 studies comprising 54,174 samples and 10,299 positive detections were included in this study. The global pooled prevalence of leptospirosis in sheep was 15.69% (95% CI: 12.69-19.25) with overall heterogeneity (I2) 98%. The prediction interval ranged from 1.09% to 75.91%, indicating wide inter-study variability. The seroprevalence was 16.16% (95% CI: 12.91-20.04) and infection prevalence was 12.98% (95% CI: 8.07-20.22), showing no significant difference (P = 0.40). In addition, the prevalence of leptospirosis in sheep differed significantly across diagnostic methods and continents (P < 0.01), indicating substantial variation influenced by both methodological and geographical factors. The funnel plot revealed marked asymmetry, suggesting potential publication bias which was confirmed by Egger's regression test (P < 0.01). In conclusion, leptospirosis is widely prevalent in sheep globally, with marked geographical and methodological heterogeneity. These findings highlight the epidemiological importance of sheep in leptospirosis transmission and underscore the need for improved surveillance, standardized diagnostic approaches, and targeted control strategies within a One Health framework.

Animals↗

PubMed2026

Seroefficacy of a 10-valent pneumococcal conjugate vaccine (Pneumosil®) compared with other pneumococcal conjugate vaccines in children.

BACKGROUND: A new 10-valent pneumococcal conjugate vaccine (PCV10SII) was prequalified by WHO in 2019 for children based on non-inferiority of immunogenicity to PCV13 and PCV10GSK. However, the efficacy of PCV10SII against pneumococcal carriage or disease has not been compared with other PCVs. We compared the risk of seroinfection in PCV10SII with PCV10GSK and PCV13-vaccinated infants. METHODS: Data were available for 716 infants from two randomised trials comparing the immunogenicity of PCV10SII with PCV13 and PCV10GSK. Serotype-specific IgG levels were measured from serum samples collected at four weeks after the primary vaccination series and at the time of booster vaccination. We defined seroinfection as any increase in serotype-specific IgG between post-primary vaccination and the booster dose, indicating likely colonisation, subclinical infection, or disease. We compared the relative risk (RR) of seroinfection between PCVs. RESULTS: There was no difference in the risk of seroinfection between PCV10SII and PCV10GSK for the shared serotypes, but PCV10SII showed better protection against 6A and 19A, not included in PCV10GSK. Compared with PCV13, the risk of seroinfection was 65% lower in PCV10SII for serotype 14 (RR = 0.35, 95% CI: 0.22, 0.57), 2.27-fold (95% CI: 1.40, 3.68) and 2.91-fold (95% CI: 1.84, 4.60) higher for 6A and 6B seroinfection, and similar for the remaining serotypes. CONCLUSION: PCV10SII demonstrated comparable seroefficacy as PCV10GSK against colonisation by serotypes common to both and may offer better coverage in countries with high prevalence of 6A and 19A disease. The serotype-specific differences in seroefficacy between PCV10SII and PCV13 should be considered when evaluating cost effectiveness. Funding Gates Foundation (INV-056261_2023).

Humans↗

PubMed2026

Detection of Rickettsia species with seroreactivity to Rickettsia tillamookensis and Rickettsia rickettsii subsp. californica in domestic dogs in Northern California.

Rickettsia species phylotype G022 (G022) and Rickettsia tillamookensis both maintain a low infection prevalence in Ixodes pacificus ticks and share a close phylogenetic history with pathogenic Rickettsia species. The transmission mechanisms and pathogenic potential of I. pacificus-borne Rickettsia are poorly understood. The low prevalence of G022 and R. tillamookensis suggests that vertebrate species are utilized for maintenance, though identification of vertebrate amplifier and reservoir hosts utilized by Rickettsia is limited. To evaluate the molecular occurrence of G022 and R. tillamookensis and the sentinel utility of domestic dogs, a molecular survey was conducted. Buffy coat and blood plasma samples from 175 domestic dogs collected from Humboldt and Sonoma counties in northern California were screened for rickettsial DNA and anti-rickettsial antibodies, respectively. Dogs were screened for antibodies against Rickettsia spp. and tested for seroreactivity against R. tillamookensis, Rickettsia rickettsii subsp. californica, and Rickettsia rhipicephali. Because G022 has not yet been isolated, this Rickettsia species was omitted from the serological survey. Of the 175 dogs tested, three (1.71%; 95% CI: 0.58%-4.90%) were seropositive for Rickettsia spp. by indirect immunofluorescence antibody assay (IFA); two dogs (1.14%; 95% CI: 0.31%-4.10%) demonstrated seroreactivity by enzyme-linked immunosorbent assay (ELISA), suggesting previous exposure to Rickettsia spp. Among dogs from Sonoma County, 2.88% (3/104; 95% CI: 1.0%-8.14%) of plasma samples were seropositive for Rickettsia spp. by IFA, and 1.92% (2/104; 95% CI: 0.53%-6.74%) demonstrated seroreactivity by ELISA, while all the dogs from Humboldt County were seronegative for both methods. Although the ELISA results were not considered species-specific, two plasma samples demonstrated the greatest seroreactivity against R. tillamookensis and R. rickettsii subsp. californica, respectively, suggesting previous exposure to Rickettsia spp. with epitope similarity to R. tillamookensis and R. rickettsii subsp. californica, respectively. No DNA was detected for G022 or R. tillamookensis by quantitative real-time PCR, with a limit of detection of approximately 3.6 target copies per reaction for G022 and 1 genomic copy per 2 μl of template DNA per reaction for R. tillamookensis.

Animals↗

PubMed2026

Global Seroprevalence of Q Fever Antibodies to Coxiella burnetii in Children and Adolescents : A Systematic Review and Meta-analysis.

OBJECTIVE: To comprehensively determine global estimates of Q fever seroprevalence in children and adolescents by conducting a systematic review and meta-analysis. DATA SOURCES: Searches of published articles in MEDLINE, Embase and Scopus databases were conducted from inception until February 2025. STUDY SELECTION: Cross-sectional studies reporting seroprevalence of Q fever/ Coxiella burnetii antibodies, using any established laboratory test, in any population of healthy children and adolescents <20 years old were included. The quality of eligible articles was assessed using a modified Newcastle-Ottawa Scale. DATA EXTRACTION: Data from eligible articles were extracted using a standardized form, which included year of publication, year(s) the study was conducted, numbers of antibody-positive cases/specific population, age, country, geographic region, serology test used and antibody titer cutoff value. DATA SYNTHESIS: DerSimonian and Laird random effects models were used to calculate pooled seroprevalence estimates and 95% confidence intervals in data from 41 eligible articles reporting 42 studies comprising 9841 children and adolescents. Q fever seroprevalence was observed in multiple countries across 7 geographic regions, and varied markedly between countries and regions, with the highest estimate observed by an individual country in Ethiopia (45%) and by region in the Middle East (14%). Seroprevalence estimates were higher in older children and adolescents ≥10 years (15%) compared with younger children <10 years of age (8%). CONCLUSION: Despite varying geographical prevalence, our findings demonstrate that widespread exposure to Q fever antigens occurs across multiple global regions in children and adolescents to potentially serious C. burnetii infection, indicating that diagnostic surveillance and preventive measures should be considered in both endemic and previously unreported areas.

Humans↗

PubMed2022

Concordance of SARS-CoV-2 Antibody Results during a Period of Low Prevalence.

Accurate, highly specific immunoassays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are needed to evaluate seroprevalence. This study investigated the concordance of results across four immunoassays targeting different antigens for sera collected at the beginning of the SARS-CoV-2 pandemic in the United States. Specimens from All of Us participants contributed between January and March 2020 were tested using the Abbott Architect SARS-CoV-2 IgG (immunoglobulin G) assay (Abbott) and the EuroImmun SARS-CoV-2 enzyme-linked immunosorbent assay (ELISA) (EI). Participants with discordant results, participants with concordant positive results, and a subset of concordant negative results by Abbott and EI were also tested using the Roche Elecsys anti-SARS-CoV-2 (IgG) test (Roche) and the Ortho-Clinical Diagnostics Vitros anti-SARS-CoV-2 IgG test (Ortho). The agreement and 95% confidence intervals were estimated for paired assay combinations. SARS-CoV-2 antibody concentrations were quantified for specimens with at least two positive results across four immunoassays. Among the 24,079 participants, the percent agreement for the Abbott and EI assays was 98.8% (95% confidence interval, 98.7%, 99%). Of the 490 participants who were also tested by Ortho and Roche, the probability-weighted percentage of agreement (95% confidence interval) between Ortho and Roche was 98.4% (97.9%, 98.9%), that between EI and Ortho was 98.5% (92.9%, 99.9%), that between Abbott and Roche was 98.9% (90.3%, 100.0%), that between EI and Roche was 98.9% (98.6%, 100.0%), and that between Abbott and Ortho was 98.4% (91.2%, 100.0%). Among the 32 participants who were positive by at least 2 immunoassays, 21 had quantifiable anti-SARS-CoV-2 antibody concentrations by research assays. The results across immunoassays revealed concordance during a period of low prevalence. However, the frequency of false positivity during a period of low prevalence supports the use of two sequentially performed tests for unvaccinated individuals who are seropositive by the first test. IMPORTANCE What is the agreement of commercial SARS-CoV-2 immunoglobulin G (IgG) assays during a time of low coronavirus disease 2019 (COVID-19) prevalence and no vaccine availability? Serological tests produced concordant results in a time of low SARS-CoV-2 prevalence and no vaccine availability, driven largely by the proportion of samples that were negative by two immunoassays. The CDC recommends two sequential tests for positivity for future pandemic preparedness. In a subset analysis, quantified antinucleocapsid and antispike SARS-CoV-2 IgG antibodies do not suggest the need to specify the antigen targets of the sequential assays in the CDC's recommendation because false positivity varied as much between assays targeting the same antigen as it did between assays targeting different antigens.

Humans↗

PubMed2025

Lanka virus, a Mus booduga-borne orthohantavirus infection-associated febrile illness in Sri Lanka.

BACKGROUND: In Sri Lanka, a high seroprevalence of antibodies against hantaviruses was reported in communities affected by chronic kidney disease of unknown etiology (CKDu). Recently, two rodent-borne hantaviruses, Lanka virus and Anjozorobe virus, were identified in these areas. However, it is unclear which virus is the source of infection in humans, and its pathogenicity is unknown. METHODOLOGY/PRINCIPAL FINDINGS: A total of 181 sera from febrile patients from two CKDu-endemic regions, Girandurukotte and Polonnaruwa, were examined and Lanka virus genome was detected in two IgM-positive febrile patients. Of 76 serum samples from patients with fever of unknown etiology collected during 2016 examined to identify hantavirus genomes, antibodies, and serotypes, 10 were IgG-positive with five of them having IgM also. They were all without clinical features of hemorrhagic fever with renal syndrome, but three patients required treatment in the intensive care unit. A serotyping strategy was established based on the antigenic difference of the glycoprotein Gn of Lanka and Anjozorobe viruses. Using this method, febrile patients were found to be infected with the Lanka virus and none of the patient sera showed Anjozorobe virus infection pattern. Additionally, a total of 373 previously diagnosed seropositive serum samples from CKDu patients and healthy residents were serotyped to categorize 87% of seropositives as Lanka virus infection. CONCLUSIONS/SIGNIFICANCE: Lanka virus carried by little Indian field mouse (Mus booduga) is transmitted to humans, likely causing febrile illness occasionally while leading to severe disease in some of the febrile patients.

Humans↗

PubMed2025

Crimean-Congo Hemorrhagic Fever Outbreak in Podor, Northern Senegal in 2022: Two Independent Emergences and Unprecedented Mortality.

Crimean-Congo hemorrhagic fever (CCHF) is a lethal zoonotic disease transmitted through tick bites and contact with infected animals or humans. As CCHF continues to expand worldwide, we report on the first severe outbreak in Senegal (Podor, Saint-Louis region) in 2022. We conducted a comprehensive outbreak investigation after a confirmed CCHF human case in Podor. This included sample collections from humans, animals, and ticks from the household and surrounding area. Human and animal samples were tested by ELISA for antibodies to CCHF virus and by reverse transcription polymerase chain reaction (RT-PCR) for CCHF virus RNA, whereas tick samples underwent CCHF RT-PCR only. Positive RT-PCR samples underwent viral genome sequencing for genetic characterization. We determined three CCHF human cases, with two deaths, as well as virus circulation in 11 ticks and in livestock, with an overall seroprevalence of 42.5%. CCHF IgG antibodies were detected in human contact cases, showing its prior prevalence in the area. Phylogenetic analyses revealed high genetic diversity within CCHF genotypes, with existence of reassortants and cocirculation of two different isolates from various origins in Mboyo and Nenette villages, where human cases were detected. The data showed a correlation between the strains identified in humans and ticks in each village, showing two independent emergences in Podor. The outbreak in Podor was probably because of the high abundance of animal hosts in this sylvopastoral area, the diversity of tick populations with the presence of the main CCHF vectors, and the increasing prevalence of CCHF virus. The surveillance in this area needs to be strengthened.

Humans↗

PubMed2025

First surveillance study of avian orthoavulavirus type 1 in wild birds in Morocco: Insights and implications for future monitoring.

BACKGROUND: Wild birds, particularly migratory species, can act as natural reservoirs and vectors of avian orthoavulavirus type 1 (AOAV-1) or Newcastle disease virus (NDV), contributing to its spread across regions and potentially threatening domestic poultry populations. AOAV-1, also known as NDV, is a major pathogen affecting avian species and poses a global threat to poultry production. It belongs to the Paramyxoviridae family and is an RNA virus encoding six key proteins, including the fusion (F) protein, which determines pathogenicity. AOAV-1 is classified into three pathotypes based on virulence: velogenic (highly pathogenic), mesogenic (moderately pathogenic), and lentogenic (mild or asymptomatic). In Morocco, AOAV-1 is endemic in poultry production systems, as evidenced by recent studies reporting a 52.1% seroprevalence and active viral RNA detection in backyard chickens in the Khemisset and Skhirat-Temara provinces; however, effective vaccination strategies have contributed to controlling the clinical signs and widespread dissemination of the virus. AIM: The main objective of this study was to investigate the presence of AOAV-1 in wild bird populations across Morocco, providing insights into possible transmission of infection affecting domestic poultry. METHODS: From November 2016 to April 2022, a total of 1984 samples were collected from 840 individual birds, encompassing 79 species, 25 families, and 12 orders. The majority of the samples belonged to Charadriiformes, Anseriformes, Pelecaniformes, and Passeriformes. Sampling was conducted at 17 wetlands and six additional locations throughout Morocco. Viral detection was performed using real-time reverse transcriptase PCR (RT-qPCR) targeting Matrix (M) and RNA polymerase (L) genes to confirm the presence of AOAV-1. RESULTS: Although the study spanned 6 years and included a large number of samples from bird orders considered primary AOAV-1 reservoirs, all samples tested negative for NDV RNA using both M and L gene targets. CONCLUSION: This study represents the first effort in Morocco to monitor wild birds for AOAV-1. The samples analyzed were initially collected for avian influenza surveillance, which shares epidemiological similarities with Newcastle's disease. However, to improve future surveillance efforts, sample collection should be optimized to target scenarios with the highest probability of virus detection.

Animals↗