RESUMO
Foot-and-mouth disease (FMD) is an ailment that causes serious damage to the productive chain, and its control through vaccination is of utmost importance for its eradication. Brazil initiated the National Foot-and-Mouth Disease Surveillance Program (PNEFA) with the aim of making the country FMD-free by 2026. As part of the program, notifications of vesicular lesions became mandatory for the Official Veterinary Service (OVS), which is responsible for verifying them. Due to its size, border areas with countries that do not have FMD-free status pose a risk to Brazil and require greater attention. This study described the profile of notifications of suspected outbreaks of vesicular syndrome in Brazil and analyzed the performance of the surveillance system. The results showed 7134 registered notifications of suspected vesicular syndrome outbreaks from 2018 to 2022, with 2022 having the highest number (n = 2343 or 32.85â¯%). The species that generated the most notifications were swine (90.99â¯%), cattle and buffaloes (7.54â¯%), goats and sheep (1.44â¯%), and others (0.03â¯%). The sources of notification were "Veterinary medicine professionals" (61.82â¯%), "Owners or employees" (13.66â¯%), "Third parties" (8.90â¯%), "OVS" (7.20â¯%), and "others" (2.66â¯%). 41.69â¯% of notifications originated from non-border municipalities, and 58.32â¯% from border areas. Only the state of Paraná account for 51.73â¯% of the total notifications. This state also accounted for 66.70â¯% of the 32.47â¯% of notifications with a final diagnosis of "absence of clinically compatible signs or susceptible animals", indicating a certain lack of knowledge in the area, leading to unnecessary notifications and system overload. The performance of the OVS was evaluated based on the service response time from notification registration trough Logistic and Negative binomial regressions. A total of 27.83â¯% of notifications did not meet the Brazilian legally specified time, and the zone related to the state of Parana needs improvements in performance. The presence and peaks of Senecavirus A cases may have influenced an increased number of swine notifications and led to a decrease in OVS response time. The results demonstrate better performance of surveillance in border areas. Given the vast territory of Brazil, it is not expected that 100â¯% of responses occur within the legal timeframe, however, the performance of the surveillance system proved to be adequate, with 86â¯% complied to the legislation. The performance indicators could be used as a monitoring tool, along with indicators to demonstrate system overload. Continued education actions are crucial for strengthening PNEFA.
Assuntos
Doenças dos Bovinos , Surtos de Doenças , Febre Aftosa , Brasil/epidemiologia , Animais , Febre Aftosa/epidemiologia , Febre Aftosa/prevenção & controle , Surtos de Doenças/veterinária , Surtos de Doenças/prevenção & controle , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/virologia , Doenças dos Bovinos/prevenção & controle , Suínos , Notificação de Doenças/estatística & dados numéricos , Ovinos , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/virologia , Doenças dos Suínos/prevenção & controle , Vigilância da População/métodos , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/virologia , Doenças dos Ovinos/prevenção & controle , Doenças das Cabras/epidemiologia , Doenças das Cabras/virologia , Doenças das Cabras/prevenção & controle , Cabras , Búfalos , Monitoramento Epidemiológico/veterináriaRESUMO
This study aims to analyze if the results from different serological assays, used alone or combined, could match the outcome of challenge infection with foot-and-mouth disease virus (FMDV) after vaccination in cattle. Day-of-challenge sera from animals that had been vaccinated 21 days before with monovalent formulations containing inactivated A Iran 96 or A Iran 99 virus strains were used. Challenge and serology were performed with A22 Iraq strain. IgG1 titers and total-IgG avidity indexes were significantly higher in protected animals (p < 0.01) while IgG2-titers were not related to protection (p > 0.05). An IgG1 avidity ELISA was developed to analyze in one step, IgG1 levels and avidity. This assay estimated protection with 96 % accuracy. A strong agreement with challenge results was achieved (K = 0.85), suggesting a role of high-affinity IgG1 in protection against FMDV. These results support the assessment of the single dilution IgG1-Avidity ELISA to predict cross-protection in FMDV-vaccinated cattle.
Assuntos
Anticorpos Antivirais , Afinidade de Anticorpos , Doenças dos Bovinos , Proteção Cruzada , Ensaio de Imunoadsorção Enzimática , Vírus da Febre Aftosa , Febre Aftosa , Imunoglobulina G , Vacinação , Vacinas Virais , Animais , Febre Aftosa/prevenção & controle , Febre Aftosa/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Bovinos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Vírus da Febre Aftosa/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Vacinas Virais/imunologia , Doenças dos Bovinos/prevenção & controle , Doenças dos Bovinos/imunologia , Proteção Cruzada/imunologia , Vacinação/métodosRESUMO
Foot-and-mouth disease is a highly contagious disease affecting cloven-hoofed animals, resulting in considerable economic losses. Its causal agent is foot-and-mouth disease virus (FMDV), a picornavirus. Due to its error-prone replication and rapid evolution, the transmission and evolutionary dynamics of FMDV can be studied using genomic epidemiological approaches. To analyze FMDV evolution and identify possible transmission routes in an Argentinean region, field samples that tested positive for FMDV by PCR were obtained from 21 farms located in the Mar Chiquita district. Whole FMDV genome sequences were obtained by PCR amplification in seven fragments and sequencing using the Sanger technique. The genome sequences obtained from these samples were then analyzed using phylogenetic, phylogeographic, and evolutionary approaches. Three local transmission clusters were detected among the sampled viruses. The dataset was analyzed using Bayesian phylodynamic methods with appropriate coalescent and relaxed molecular clock models. The estimated mean viral evolutionary rate was 1.17 × 10- 2 substitutions/site/year. No significant differences in the rate of viral evolution were observed between farms with vaccinated animals and those with unvaccinated animals. The most recent common ancestor of the sampled sequences was dated to approximately one month before the first reported case in the outbreak. Virus transmission started in the south of the district and later dispersed to the west, and finally arrived in the east. Different transmission routes among the studied herds, such as non-replicating vectors and close contact contagion (i.e., aerosols), may be responsible for viral spread.
Assuntos
Vírus da Febre Aftosa , Picornaviridae , Animais , Vírus da Febre Aftosa/genética , Argentina/epidemiologia , Teorema de Bayes , FilogeniaRESUMO
Foot and mouth disease is a highly contagious viral disease that poses a significant economic threat to cloven-hoofed animals, including cattle and sheep. The emergence of a novel foot and mouth disease virus-A isolate, FMDV-A-Egy-AHRI-RL385-Ven-2022, in Egypt in 2022 has raised concerns about its potential impact on existing vaccination programs. Given that vaccination is a key strategy for foot and mouth disease virus control, the present study was aimed to assess the cross-protective efficacy of both local and imported inactivated vaccines against this new threat. Through challenge experiments and serum neutralization tests, we observed limited effectiveness of both vaccine types. The calculated r1-values at 28 days post-vaccination indicated a minimal immune response to FMDV-A-Egy-AHRI-RL385-Ven-2022 (0.176 and 0.175 for local and imported vaccines, respectively). Challenge experiments further confirmed these findings, revealing 0percent protection from the local vaccine and only 20percent rotection from imported vaccines by day 7 post-challenge. These results underscore the urgent need to update existing foot and mouth disease virus vaccines in Egypt by incorporating the newly circulating FMDV-A-Egy-AHRI-RL385-Ven-2022 strain. This proactive measure is crucial to prevent future outbreaks and ensure effective disease control(AU)
La fiebre aftosa es una enfermedad vírica muy contagiosa que supone una importante amenaza económica para los animales biungulados, entre ellos el ganado vacuno y ovino. La aparición de un nuevo aislado del virus A de la fiebre aftosa, el FMDV-A-Egy-AHRI-RL385-Ven-2022, en Egipto en 2022 ha suscitado preocupación por su posible impacto en los programas de vacunación existentes. Dado que la vacunación es una estrategia clave para el control del virus de la fiebre aftosa, el objetivo del presente estudio fue evaluar la eficacia protectora cruzada de las vacunas inactivadas locales e importadas frente a esta nueva amenaza. Mediante experimentos de desafío y pruebas de seroneutralización, observamos una eficacia limitada de ambos tipos de vacuna. Los valores r1 calculados a los 28 días posvacunación indicaron una respuesta inmunitaria mínima frente a FMDV-A-Egy-AHRI-RL385-Ven-2022 (0,176 y 0,175 para las vacunas local e importada, respectivamente). Los experimentos de provocación confirmaron aún más estos resultados, revelando un 0 por ciento de protección de la vacuna local y sólo un 20 por ciento de protección de las vacunas importadas al séptimo día después de la provocación. Estos resultados subrayan la urgente necesidad de actualizar las vacunas existentes contra el virus de la fiebre aftosa en Egipto incorporando la nueva cepa circulante FMDV-A-Egy-AHRI-RL385-Ven-2022. Esta medida proactiva es crucial para prevenir futuros brotes y garantizar un control eficaz de la enfermedad(AU)
Assuntos
Animais , Surtos de Doenças , Gado , Febre Aftosa/epidemiologia , Vacinas , EgitoRESUMO
The role of water buffaloes in foot-and-mouth disease (FMD) epidemiology as one of the major hosts of the virus that can develop persistent asymptomatic infection highlights the importance of sustaining surveillance on the antibody response elicited by vaccination in these animals. There is gap in the knowledge on how serological assays that measure antibodies against capsid proteins perform with buffalo samples and which would be the most reliable test to substitute the virus neutralization test (VNT) a cumbersome and low-throughput tool for field surveillance. Alternatively, the liquid-phase blocking sandwich ELISA (LPBE) is commonly used. Previous data from our laboratory demonstrated that the vaccine-induced antibodies assessed by the LPBE yielded low specificity with buffaloes' samples. In contrast, a single-dilution avidity ELISA (AE) aimed to detect high-avidity antibodies against exposed epitopes, combined with an indirect ELISA (IE) to assess IgG levels, produced more reliable results. Here we analyzed for the first time the kinetics of the antibodies induced by vaccination in two different buffalo herds (n = 91) over 120 days using AE, IE, LPBE, and the VNT. Kinetics were similar in the different assays, with an increase of antibodies between 0- and 14-days post-vaccination (dpv) which were maintained thereafter. VNT and AE results were concordant (Kappa value = 0.76), and both assays revealed a decay in the antibody response in calves with maternal antibodies at 90 and 120 dpv, which was not evidenced by the LPBE. These results show that kinetics of antibody responses to FMD vaccination are similar in buffalo and cattle, and support the use of indirect ELISA assays, in particular Avidity ELISA, as alternatives to the VNT for vaccine-immunity monitoring irrespectively of the animal's passive or active immune status.
RESUMO
FMD remains endemic in many Asian and African countries where multiple variants of serotypes O and A, among others, currently circulate. Due to lack of cross-protection between serotypes and incomplete protection between some strains even within a serotype, an important challenge for the application of effective vaccination programs is to select highly immunogenic and widely cross-reactive vaccine strains. Adaptation of a candidate field virus for use as a vaccine can be quite complex, so that whenever possible, the use of well-established vaccine viruses could have enormous advantages. FMD vaccine strains harmonized for use in South America have shown excellent results in FMD control, not only in the region, where it is still used systematically as a preventive measure, but also more recently in some Asian countries. To gain further insight into the immunogenic spectrum of these strains, VN tests (VNT) were performed with sera from cattle and/or pigs vaccinated with monovalent (type O) or trivalent (types O and A) formulations against 122 type O and 32 type A field viruses isolated from 35 countries in Asia and Africa, belonging to different lineages. Almost all VNT titers obtained were within the expected protective level, indicating the wide immunogenic spectrum of high potency FMD vaccines formulated with O1 Campos, A24 Cruzeiro and A Argentina 2001 South American vaccine strains belonging to EURO-SA topotypes against currently active viruses from other topotypes. These in vitro results are in line with previously reported in vivo challenge tests in pigs against three A/ASIA/Sea-97 isolates and two isolates belonging to type O lineages O/SEA/Mya-98 and O/ME-SA/Ind-2001e.
Assuntos
Doenças dos Bovinos , Vírus da Febre Aftosa , Febre Aftosa , Vacinas Virais , Bovinos , Animais , Suínos , Febre Aftosa/epidemiologia , Argentina/epidemiologia , Antígenos Virais , Sorogrupo , Anticorpos AntiviraisRESUMO
Quantitative risk assessment was used to estimate the risk of introducing foot-and-mouth disease (FMD) through bone-in beef from Argentina (FMD-free with vaccination status) into other FMD-free countries. A stochastic model was built to characterize all the steps from primary production to bone-in beef export and introduction into an FMD-free country. The probability that bone-in beef from at least one animal infected with the FMD virus (FMDV) was exported during a year was 5.27 × 10-3 (95% CI <10-10 - 5.19 x 10-2) or in other words one case in 190 years. The risk of FMDV introduction was sensitive to the probability of an outbreak occurring in Argentina (r [Spearman´s rank correlation] = 0.99) and the number of herds affected during an outbreak (r = 0.10). Additionally, the probability that susceptible animals in the importing country came into contact with infective material (bones) and generated an outbreak was 6.16 × 10-4 (95% CI <10-10 - 6.20 ×10-3) or one FMD outbreak every 1623 years on average. Based on the quantitative risk assessment results, the probability of FMDV introduction into a FMD-free country where vaccination is not practiced from a FMD-free country where vaccination is practiced associated with bone-in beef trade from Argentina was negligible. The risk of an FMD outbreak caused by the potential introduction of the FMDV was associated with the existing conditions in the country. Thus, maintaining the FMD-free status with or without vaccination would not be relevant.
Assuntos
Doenças dos Bovinos , Vírus da Febre Aftosa , Febre Aftosa , Animais , Bovinos , Febre Aftosa/epidemiologia , Febre Aftosa/prevenção & controle , Argentina/epidemiologia , Medição de Risco , Vacinação/veterinária , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/prevenção & controleRESUMO
Introduction: Physical and non-physical processes that occur in nature may influence biological processes, such as dissemination of infectious diseases. However, such processes may be hard to detect when they are complex systems. Because complexity is a dynamic and non-linear interaction among numerous elements and structural levels in which specific effects are not necessarily linked to any one specific element, cause-effect connections are rarely or poorly observed. Methods: To test this hypothesis, the complex and dynamic properties of geo-biological data were explored with high-resolution epidemiological data collected in the 2001 Uruguayan foot-and-mouth disease (FMD) epizootic that mainly affected cattle. County-level data on cases, farm density, road density, river density, and the ratio of road (or river) length/county perimeter were analyzed with an open-ended procedure that identified geographical clustering in the first 11 epidemic weeks. Two questions were asked: (i) do geo-referenced epidemiologic data display complex properties? and (ii) can such properties facilitate or prevent disease dissemination? Results: Emergent patterns were detected when complex data structures were analyzed, which were not observed when variables were assessed individually. Complex properties-including data circularity-were demonstrated. The emergent patterns helped identify 11 counties as 'disseminators' or 'facilitators' (F) and 264 counties as 'barriers' (B) of epidemic spread. In the early epidemic phase, F and B counties differed in terms of road density and FMD case density. Focusing on non-biological, geographical data, a second analysis indicated that complex relationships may identify B-like counties even before epidemics occur. Discussion: Geographical barriers and/or promoters of disease dispersal may precede the introduction of emerging pathogens. If corroborated, the analysis of geo-referenced complexity may support anticipatory epidemiological policies.
RESUMO
Large epidemics provide the opportunity to understand the epidemiology of diseases under the specific conditions of the affected population. Whilst foot-and-mouth disease (FMD) epidemics have been extensively studied in developed countries, epidemics in developing countries have been sparsely studied. Here we address this limitation by systematically studying the 2001 epidemic in Uruguay where a total of 2,057 farms were affected. The objective of this study was to identify the risk factors (RF) associated with infection and spread of the virus within the country. The epidemic was divided into four periods: (1) the high-risk period (HRP) which was the period between the FMD virus introduction and detection of the index case; (2) the local control measures period (LCM) which encompassed the first control measures implemented before mass vaccination was adopted; (3) the first mass vaccination, and (4) the second mass vaccination round. A stochastic model was developed to estimate the time of initial infection for each of the affected farms. Our analyses indicated that during the HRP around 242 farms were probably already infected. In this period, a higher probability of infection was associated with: (1) animal movements [OR: 1.57 (95% CI: 1.19-2.06)]; (2) farms that combined livestock with crop production [OR: 1.93 (95% CI: 1.43-2.60)]; (3) large and medium farms compared to small farms (this difference was dependent on regional herd density); (4) the geographical location. Keeping cattle only (vs farms that kept also sheep) was a significant RF during the subsequent epidemic period (LCM), and remained as RF, together with large farms, for the entire epidemic. We further explored the RF associated with FMDV infection in farms that raised cattle by fitting another model to a data subset. We found that dairy farms had a higher probability of FMDV infection than beef farms during the HRP [OR: 1.81 (95% CI: 1.12-2.83)], and remained as RF until the end of the first round of vaccination. The delay in the detection of the index case associated with unrestricted animal movements during the HRP may have contributed to this large epidemic. This study contributes to the knowledge of FMD epidemiology in extensive production systems.