Publications by authors named "Anna B Ludi"

Multiple transboundary animal diseases (TADs) circulate in Plateau State, Nigeria, where livestock keeping is common and contributes to both the physical and socio-economic well-being of a large proportion of the population. In this study, we explored the potential for environmental sampling to detect viruses causing TADs circulating in the region. Electrostatic dust cloths were used to swab areas of the environment likely to have contact with secretions and excretions from infected animals.

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Article Synopsis
  • A study examined foot-and-mouth disease (FMD) outbreaks in Asiatic black bears and Malayan sun bears at a Vietnamese rescue center, analyzing data from 79 bears and blood samples from 23 bears over time.
  • The outbreaks showed significant attack rates (18.75% and 77.77%) and basic reproduction numbers (1.11 and 1.92), indicating the disease spreads easily among bears.
  • Results revealed that older bears were less likely to exhibit clinical signs, and while most bears without symptoms tested positive for antibodies post-outbreak, it demonstrated that FMD can cause both clinical and subclinical diseases, leading to long-lasting immunity.
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Vaccination is widely used to control foot-and-mouth disease (FMD), but maternal antibodies may interfere with the response to vaccination in calves. This study, conducted on a regularly vaccinated Malaysian dairy farm, aimed to optimise the vaccination regime by measuring the in vitro neutralising virus antibody responses of 51 calves before and after vaccination with a one or two dose vaccination regime starting at 2-7 months old. The presence of maternal antibodies was associated with poor post-vaccination antibody responses after a single dose of vaccine in calves less than 6 months old.

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The recent introduction of foot-and-mouth disease (FMD) virus serotype O (O/EA-2 topotype) in Southern Africa has changed the epidemiology of the disease and vaccine requirements of the region. Commercial and subsistence cattle herds in Zambia were vaccinated with an FMD virus serotype O Manisa vaccine according to a double- or single-dose vaccination schedule. Heterologous antibody responses induced by this vaccine against a representative O/EA-2 virus from Zambia were determined.

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Vaccines are a critical tool for the control strategy for foot-and-mouth disease (FMD) in Mongolia where sporadic outbreaks regularly occur. A two-dose primary vaccination course is recommended for most commercial vaccines though this can be logistically challenging to deliver among nomadic pastoralist systems which predominate in the country. Although there is evidence that very high potency vaccines can provide prolonged duration of immunity, this has not been demonstrated under field conditions using commercially available vaccines.

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Controlling foot-and-mouth disease (FMD) by vaccination requires adequate population coverage and high vaccine efficacy under field conditions. To assure veterinary services that animals have acquired sufficient immunity, strategic post-vaccination surveys can be conducted to monitor the coverage and performance of the vaccine. Correct interpretation of these serological data and an ability to derive exact prevalence estimates of antibody responses requires an awareness of the performance of serological tests.

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Many small ruminants infected with foot-and-mouth disease (FMD) remain asymptomatic, with the capacity to promote silent viral spread within domestic and wildlife species. However, little is known about the epidemiological role played by small ruminants in FMD. In particular, there are few studies that examine FMD seroprevalence, spatial patterns and risk factors for exposure in small ruminants.

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Antigen banks have been established to supply foot-and-mouth disease virus (FMDV) vaccines at short notice to respond to incursions or upsurges in cases of FMDV infection. Multiple vaccine strains are needed to protect against specific FMDV lineages that circulate within six viral serotypes that are unevenly distributed across the world. The optimal selection of distinct antigens held in a bank must carefully balance the desire to cover these risks with the costs of purchasing and maintaining vaccine antigens.

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Serology is widely used to predict whether vaccinated individuals and populations will be protected against infectious diseases, including foot-and-mouth disease (FMD), which affects cloven-hoofed animals. Neutralising antibody titres to FMD challenge viruses correlate to protection against FMD, for vaccinated cattle that are infected with the same strain as in the vaccine (homologous protection). Similar relationships exist for cross-strain protection between different vaccine and challenge viruses, although much less data are available for these heterologous studies.

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Crimean-Congo hemorrhagic fever (CCHF) is a priority emerging disease. CCHF, caused by the CCHF virus (CCHFV), can lead to hemorrhagic fever in humans with severe cases often having fatal outcomes. CCHFV is maintained within a tick-vertebrate-tick cycle, which includes domestic animals.

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Antibodies to the foot-and-mouth disease virus (FMDV) capsid induced by infection or vaccination can provide serotype-specific protection and be measured using virus neutralization tests and viral structural-protein (SP-)ELISAs. Separate tests are needed for each serotype, but cross-serotype reactions complicate serotyping. In this study, inter-serotypic responses were quantified for five SP-ELISA formats by testing 294 monovalent mainly bovine sera collected following infection, vaccination, or vaccination and infection with one of five serotypes of FMDV.

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Background And Aim: Serological assays are widely used to monitor the performance of foot-and-mouth disease (FMD) vaccines to estimate vaccination coverage and to ensure that vaccinated animals generate adequate immune responses. This study aimed to measure the FMD virus (FMDV)-specific responses in cattle and sheep after a single dose of a trivalent FMD vaccine containing serotypes A, O, and Asia-1, and to use these sera to calibrate virus neutralization tests (VNTs) and serotype-specific serological enzyme-linked immunoassays (ELISAs) that can measure post-vaccination responses.

Materials And Methods: Sera were collected from cattle (n=10) and sheep (n=10) on 0, 21, and 56 days after immunization with an imported aqueous formulated FMD vaccine.

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Foot-and-mouth disease (FMD) is a highly contagious animal disease caused by an RNA virus subdivided into seven serotypes that are unevenly distributed in Asia, Africa, and South America. Despite the challenges of controlling FMD, since 1996 there have been only two outbreaks attributed to serotype C, in Brazil and in Kenya, in 2004. This article describes the historical distribution and origins of serotype C and its disappearance.

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The recent emergence and circulation of the A/ASIA/G-VII (A/G-VII) lineage of foot-and-mouth disease virus (FMDV) in the Middle East has resulted in the development of homologous vaccines to ensure susceptible animals are sufficiently protected against clinical disease. However, a second serotype A lineage called A/ASIA/Iran-05 (A/IRN/05) continues to circulate in the region and it is therefore imperative to ensure vaccine strains used will protect against both lineages. In addition, for FMDV vaccine banks that usually hold a limited number of strains, it is necessary to include strains with a broad antigenic coverage.

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The presence of foot-and-mouth disease virus (FMDV) of the O/ME-SA/Ind-2001e sublineage within Pakistan was initially detected in two samples collected during 2019. Analysis of further serotype O FMDVs responsible for disease outbreaks in 2019-2020 in the country has now identified the spread of this sublineage to 10 districts within two separate provinces in North-Eastern and North-Western Pakistan. Phylogenetic analysis indicates that these viruses are closely related to those circulating in Bhutan, Nepal and India.

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Outbreaks that occur as a result of zoonotic spillover from an animal reservoir continue to highlight the importance of studying the disease interface between species. One Health approaches recognise the interdependence of human and animal health and the environmental interplay. Improving the understanding and prevention of zoonotic diseases may be achieved through greater consideration of these relationships, potentially leading to better health outcomes across species.

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Serologic assays used to detect antibodies to nonstructural proteins (NSPs) of foot-and-mouth disease virus (FMDV) are used for disease surveillance in endemic countries, and are essential to providing evidence for freedom of the disease with or without vaccination and to recover the free status of a country after an outbreak. In a 5-site inter-laboratory study, we compared the performance of 2 commercial NSP ELISA kits (ID Screen FMD NSP ELISA single day [short] and overnight protocols, ID.Vet; PrioCHECK FMDV NS antibody ELISA, Thermo Fisher Scientific).

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Since 2015, outbreaks of foot-and-mouth disease (FMD) in the Middle East have been caused by a new emerging viral lineage, A/ASIA/G-VII. vaccine matching data indicated that this virus poorly matched (low r-value) with vaccines that were being used in the region as well as most other commercially available vaccines. The aim of this study was to assess the performance of two candidate vaccines against challenge with a representative field virus from the A/ASIA/G-VII lineage.

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Foot-and-mouth disease (FMD) is a high impact viral disease of livestock for which vaccines are extensively used in control. Mongolia has regular incursions of FMD virus that are typically limited to the eastern region although large epidemics are occasionally reported in the normally disease-free western areas. Vaccines are imported and form an important component of the control strategy.

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The genome sequences of three serotype O foot-and-mouth disease viruses (FMDVs) isolated from outbreaks in Pakistan in 2016 and 2017 are described. Despite all three isolates being classified in the same FMDV genetic sublineage, two of them displayed a distinct antigenic phenotype against commonly used vaccine strains.

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Livestock production in Africa is key to national economies, food security and rural livelihoods, and > 85% of livestock keepers live in extreme poverty. With poverty elimination central to the Sustainable Development Goals, livestock keepers are therefore critically important. Foot-and-mouth disease is a highly contagious livestock disease widespread in Africa that contributes to this poverty.

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In 2015, outbreaks of foot-and-mouth disease (FMD) in the Middle East were discovered to be caused by a viral lineage (A/ASIA/G-VII), which has recently emerged from the Indian sub-continent. In vitro vaccine matching data generated by the World Reference Laboratory (WRLFMD) indicated that A/ASIA/G-VII field viruses were poorly matched with vaccines (A-SAU-95, A22 IRQ and A-IRN-05) that are already used in the region. In order to assess the likely performance of one of these commercially available FMD vaccines, sixteen cattle were vaccinated with a polyvalent vaccine which contained two serotype A components (A-SAU-95 and A-IRN-05) with a homologous potency of at least 6PD, and two cattle were left unvaccinated as controls.

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In 2015, foot-and-mouth disease (FMD) viruses of the A/ASIA/G-VII lineage emerged from the Indian sub-continent to cause outbreaks in the Middle and Near East. A factor which has been proposed to have contributed to the rapid spread of this lineage is the poor in vitro vaccine-match of field isolates to vaccine strains that are commonly used in the region. This study used data from outbreaks on four large-scale dairy farms using routine vaccination in Saudi Arabia, to evaluate the impact of vaccination and learn how to manage outbreaks more effectively in this setting.

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Outbreaks of foot-and-mouth disease (FMD) in North Africa (2013) and the Gulf States (2013) of the Middle East have been caused by a FMD viral lineage (O/ME-SA/Ind-2001) that was before 2013 restricted to the Indian Sub-continent. This study was undertaken to assess the in vivo efficacy of a FMD virus emergency vaccine type O Manisa against heterologous challenge with a representative field virus (O/ALG/3/2014) from this emerging lineage. This widely available vaccine was selected since in vitro vaccine-matching results gave inconclusive results as to whether or not it would be protective.

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