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1.
PLoS One ; 15(5): e0232489, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32453749

RESUMO

The foot-and-mouth disease is an ever-present hazard to the livestock industry due to the huge economic consequences following an outbreak that necessitates culling of possibly infected animals in vast numbers. The disease is highly contagious and previous epizootics have shown that it spreads by many routes. One such route is airborne transmission, which has been investigated in this study by means of a detailed multilevel model that includes all scales of an outbreak. Local spread within an infected farm is described by a stochastic compartment model while the spread between farms is quantified by atmospheric dispersion simulations using a network representation of the set of farms. The model was applied to the Swedish livestock industry and the risk for an epizootic outbreak in Sweden was estimated using the basic reproduction number of each individual livestock-holding farm as the endpoint metric. The study was based on comprehensive official data sets for both the current livestock holdings and regional meteorological conditions. Three species of farm animals are susceptible to the disease and are present in large numbers: cattle, pigs and sheep. These species are all included in this study using their individual responses and consequences to the disease. It was concluded that some parts of southern Sweden are indeed preconditioned to harbor an airborne epizootic, while the sparse farm population of the north renders such events unlikely to occur there. The distribution of the basic reproduction number spans over several orders of magnitudes with low risk of disease spread from the majority of the farms while some farms may act as very strong disease transmitters. The results may serve as basic data in the planning of the national preparedness for this type of events.


Assuntos
Febre Aftosa/transmissão , Modelos Biológicos , Microbiologia do Ar , Movimentos do Ar , Animais , Número Básico de Reprodução , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/transmissão , Simulação por Computador , Surtos de Doenças/veterinária , Expiração , Fazendas , Febre Aftosa/epidemiologia , Febre Aftosa/virologia , Vírus da Febre Aftosa/isolamento & purificação , Vírus da Febre Aftosa/patogenicidade , Gado , Análise Multinível , Estações do Ano , Ovinos , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/transmissão , Sus scrofa , Suécia/epidemiologia , Suínos , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/transmissão
2.
PLoS One ; 15(1): e0219805, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31917824

RESUMO

Footrot is a worldwide economically important, painful, contagious bacterial foot disease of domestic and wild ungulates caused by Dichelobacter nodosus. Benign and virulent strains have been identified in sheep presenting with mild and severe lesions, respectively. However, in Alpine ibex (Capra ibex ibex), both strains have been associated with severe lesions. Because the disease is widespread throughout sheep flocks in Switzerland, a nationwide footrot control program for sheep focusing on virulent strains shall soon be implemented. The aim of this cross-sectional study was to estimate the nationwide prevalence of both strain groups of D. nodosus in four wild indigenous ruminant species and to identify potential susceptible wildlife maintenance hosts that could be a reinfection source for domestic sheep. During two years (2017-2018), interdigital swabs of 1,821 wild indigenous ruminant species (Alpine ibex, Alpine chamois (Rupicapra rupicapra), roe deer (Capreolus capreolus), red deer (Cervus elaphus)) were analysed by Real-Time PCR. Furthermore, observed interspecies interactions were documented for each sample. Overall, we report a low prevalence of D. nodosus in all four indigenous wild ruminants, for both benign (1.97%, N = 36, of which 31 red deer) and virulent (0.05%, N = 1 ibex) strains. Footrot lesions were documented in one ibex with virulent strains, and in one ibex with benign strains. Interspecific interactions involving domestic livestock occurred mainly with cattle and sheep. In conclusion, the data suggest that wild ungulates are likely irrelevant for the maintenance and spread of D. nodosus. Furthermore, we add evidence that both D. nodosus strain types can be associated with severe disease in Alpine ibex. These data are crucial for the upcoming nationwide control program and reveal that wild ruminants should not be considered as a threat to footrot control in sheep in this context.


Assuntos
Animais Selvagens/microbiologia , Doenças dos Bovinos/epidemiologia , Dichelobacter nodosus/patogenicidade , Pododermatite Necrótica dos Ovinos/epidemiologia , Doenças dos Ovinos/epidemiologia , Animais , Bovinos , Doenças dos Bovinos/patologia , Doenças dos Bovinos/transmissão , Estudos Transversais , Cervos/microbiologia , Dichelobacter nodosus/classificação , Dichelobacter nodosus/genética , Monitoramento Epidemiológico , Pododermatite Necrótica dos Ovinos/patologia , Pododermatite Necrótica dos Ovinos/transmissão , Cabras/microbiologia , Prevalência , Rupicapra/microbiologia , Ovinos/microbiologia , Doenças dos Ovinos/patologia , Doenças dos Ovinos/transmissão , Suíça/epidemiologia
3.
Transbound Emerg Dis ; 67(1): 223-233, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31482692

RESUMO

Foot-and-mouth disease (FMD) is highly contagious and easily transmitted among species of cloven-hoofed animals. To investigate the transmission of FMD virus (FMDV) among different animal species, experimental infections using the O/JPN/2010 strain were performed in cows, goats and pigs. One cow or two goats/pigs were housed with a different species of inoculated animals, and clinical observations, virus shedding and antibody responses were analysed daily. Whilst all cows and goats were infected horizontally by contact with inoculated pigs, transmission from cows to goats/pigs and from goats to cows/pigs was not observed in all in-contact animals. In particular, no pigs were infected horizontally by contact with inoculated goats. Comparison with our previous study on experimental infections among animals of the same species indicates that horizontal transmission occurred more easily between animals of the same species than between those of the different species. These findings will be useful for establishing and performing species-specific countermeasures in farms and regions where multiple species of animals coexist in potential future outbreaks.


Assuntos
Anticorpos Antivirais/sangue , Doenças dos Bovinos/epidemiologia , Surtos de Doenças/veterinária , Vírus da Febre Aftosa/imunologia , Febre Aftosa/transmissão , Doenças das Cabras/epidemiologia , Doenças dos Suínos/epidemiologia , Animais , Bovinos , Doenças dos Bovinos/transmissão , Doenças dos Bovinos/virologia , Feminino , Febre Aftosa/epidemiologia , Febre Aftosa/virologia , Vírus da Febre Aftosa/fisiologia , Doenças das Cabras/transmissão , Doenças das Cabras/virologia , Cabras , Especificidade de Hospedeiro , Suínos , Doenças dos Suínos/transmissão , Doenças dos Suínos/virologia , Eliminação de Partículas Virais
4.
Theriogenology ; 141: 41-47, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31518727

RESUMO

Bovine leptospirosis is often associated with host-adapted leptospires infections, such as strains belonging to the Sejroe serogroup. Although bovine leptospirosis by adapted strains may result in abortions, fetal death, premature births and the birth of weak and/or low-weight calves, this infection is more closely associated with subtler syndromes, such as subfertility and early embryonic death. In this way, this silent disease can go unnoticed and undiagnosed, compromising reproductive efficiency with a consequent decrease in the productivity of herds over long periods. For many years, genital tract infection has been considered a secondary effect of renal infection with the assumption being that leptospires are found in the genital tract due to bacteremia caused by renal colonization. In contrast to this hypothesis, there is some evidence in the literature that suggests that genital leptospirosis should be considered a specific syndrome dissociated from renal/systemic disease. Therefore, this paper aims to gather and critically analyze information about genital leptospirosis in cattle, considering the disease a distinct syndrome, herein denominated bovine genital leptospirosis (BGL), that requires a unique approach to diagnosis and treatment.


Assuntos
Doenças dos Bovinos/microbiologia , Leptospirose/veterinária , Doenças Bacterianas Sexualmente Transmissíveis/veterinária , Aborto Animal/microbiologia , Animais , Bovinos , Doenças dos Bovinos/transmissão , Leptospira/classificação , Leptospira/fisiologia , Leptospirose/patologia , Leptospirose/transmissão , Doenças Bacterianas Sexualmente Transmissíveis/patologia
5.
BMC Vet Res ; 15(1): 437, 2019 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-31801536

RESUMO

BACKGROUND: Tuberculosis remains a major public health challenge globally with increasing risks for inter-transmission between pastoralists and cattle in Nigeria. This study was aimed at using molecular tools to establish zoonotic transmission of tuberculosis between pastoralists and their cattle in Ebonyi State, Nigeria. Sputum (n = 149) and milk (n = 144) samples from pastoralists and cattle, respectively were screened on the assumption of subclinical infections considering unguarded human-livestock interactions. Isolates obtained were analysed using deletion typing, spoligotyping and 24-Mycobacterial Interspersed Repetitive Unit-Variable Number Tandem Repeats (MIRU-VNTR). RESULTS: Fifty-four MTC were confirmed by deletion typing and were differentiated accordingly (M. tuberculosis: pastoralists =42, cattle = 2; M. bovis: pastoralists =1; M. africanum: pastoralists =9). Spoligotyping indicated 59.2% Uganda I/SIT46 (pastoralists =28; cattle = 1), 16.3% Latin American Mediterranean/SIT61 (pastoralists =8), 2.0% T/SIT53 (pastoralists =1) strains of M. tuberculosis and new strains of M. bovis and M. africanum. The 24-MIRU-VNTR of selected predominant cluster isolates shared by cattle and pastoralists (Uganda I/SIT46: pastoralists =9; cattle = 1) showed the same number of copies at each of the repetitive loci. CONCLUSIONS: Mycobacterium bovis was confirmed in humans and a reverse zoonotic tuberculosis transmission from an emerging Uganda I M. tuberculosis strain between pastoralists and cattle in Nigeria evidenced by MIRU-VNTR. Using molecular tools will help mitigate disease burden through informed epidemiological insights.


Assuntos
Doenças dos Bovinos/microbiologia , Doenças Transmissíveis Emergentes/veterinária , Mycobacterium tuberculosis/genética , Tuberculose Bovina/microbiologia , Zoonoses/microbiologia , Animais , Técnicas de Tipagem Bacteriana/veterinária , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/transmissão , Doenças Transmissíveis Emergentes/microbiologia , Doenças Transmissíveis Emergentes/transmissão , DNA Bacteriano , Humanos , Leite/microbiologia , Epidemiologia Molecular , Mycobacterium tuberculosis/isolamento & purificação , Nigéria/epidemiologia , Escarro/microbiologia , Tuberculose Bovina/epidemiologia , Tuberculose Bovina/transmissão , Zoonoses/epidemiologia , Zoonoses/transmissão
6.
J Microbiol Biotechnol ; 29(12): 2022-2025, 2019 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-31752068

RESUMO

Several animal species including pigs are directly involved in the zoonotic transmission of the hepatitis E virus (HEV) to humans. This study was conducted to detect HEV in bovine and porcine raw livers by nested reverse transcription-polymerase chain reaction. Zoonotic HEV strains were identified in 1.0 and 3.0% of the tested bovine and porcine livers, respectively. HEV-4 was detected in the bovine livers, but both HEV-3 and HEV-4 were identified in the porcine livers. These results indicate that zoonotic transmission of HEV may occur via consumption of raw or undercooked livers of pigs and cattle.


Assuntos
Vírus da Hepatite E/isolamento & purificação , Hepatite E/virologia , Fígado/virologia , Animais , Bovinos , Doenças dos Bovinos/transmissão , Doenças dos Bovinos/virologia , Contaminação de Alimentos , Hepatite E/transmissão , Vírus da Hepatite E/classificação , Vírus da Hepatite E/genética , Filogenia , Suínos , Doenças dos Suínos/transmissão , Doenças dos Suínos/virologia
7.
PLoS Pathog ; 15(10): e1008003, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31581229

RESUMO

Specific Escherichia coli isolates lysogenised with prophages that express Shiga toxin (Stx) can be a threat to human health, with cattle being an important natural reservoir. In many countries the most severe pathology is associated with enterohaemorrhagic E. coli (EHEC) serogroups that express Stx subtype 2a. In the United Kingdom, phage type (PT) 21/28 O157 strains have emerged as the predominant cause of life-threatening EHEC infections and this phage type commonly encodes both Stx2a and Stx2c toxin types. PT21/28 is also epidemiologically linked to super-shedding (>103 cfu/g of faeces) which is significant for inter-animal transmission and human infection as demonstrated using modelling studies. We demonstrate that Stx2a is the main toxin produced by stx2a+/stx2c+ PT21/28 strains induced with mitomycin C and this is associated with more rapid induction of gene expression from the Stx2a-encoding prophage compared to that from the Stx2c-encoding prophage. Bacterial supernatants containing either Stx2a and/or Stx2c were demonstrated to restrict growth of bovine gastrointestinal organoids with no restriction when toxin production was not induced or prevented by mutation. Isogenic strains that differed in their capacity to produce Stx2a were selected for experimental oral colonisation of calves to assess the significance of Stx2a for both super-shedding and transmission between animals. Restoration of Stx2a expression in a PT21/28 background significantly increased animal-to-animal transmission and the number of sentinel animals that became super-shedders. We propose that while both Stx2a and Stx2c can restrict regeneration of the epithelium, it is the relatively rapid and higher levels of Stx2a induction, compared to Stx2c, that have contributed to the successful emergence of Stx2a+ E. coli isolates in cattle in the last 40 years. We propose a model in which Stx2a enhances E. coli O157 colonisation of in-contact animals by restricting regeneration and turnover of the colonised gastrointestinal epithelium.


Assuntos
Doenças dos Bovinos/transmissão , Células Epiteliais/microbiologia , Infecções por Escherichia coli/veterinária , Escherichia coli O157/efeitos dos fármacos , Íleo/microbiologia , Organoides/microbiologia , Toxina Shiga II/farmacologia , Animais , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/microbiologia , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Infecções por Escherichia coli/tratamento farmacológico , Infecções por Escherichia coli/microbiologia , Escherichia coli O157/isolamento & purificação , Íleo/citologia , Íleo/metabolismo , Masculino , Organoides/crescimento & desenvolvimento , Organoides/metabolismo , Virulência
8.
Parasit Vectors ; 12(1): 464, 2019 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-31585545

RESUMO

BACKGROUND: Bluetongue disease of ruminants is a typical insect-borne disease caused by bluetongue virus (BTV) of the genus Orbivirus (family Reoviridae) and transmitted by some species of Culicoides (Diptera: Ceratopogonidae). Recently, the detection of BTV in yaks in high altitude meadows of the Shangri-La district of Yunnan Province, China, prompted an investigation of the Culicoides fauna as potential vectors of BTV. METHODS: A total of 806 Culicoides midges were collected by light trapping at three sites at altitudes ranging from 1800 to 3300 m. The species were identified based on morphology and the DNA sequences of cytochrome c oxidase subunit 1 (cox1). PCR and quantitative PCR following reverse transcription were used to test for the presence of BTV RNA in Culicoides spp. A phylogenetic analysis was used to analyze the cox1 sequences of some specimens. RESULTS: Four species dominated these collections and cox1 barcoding revealed that at least two of these appear to belong to species new to science. Culicoides tainanus and a cryptic species morphologically similar to C. tainanus dominated low altitude valley collections while C. nielamensis was the most abundant species in the high-altitude meadow. A species related to C. obsoletus occurred at all altitudes but did not dominate any of the collections. BTV RT-qPCR analysis detected BTV RNA in two specimens of C. tainanus, in one specimen closely related to C. tainanus and in one specimen closely related to C. obsoletus by barcode sequencing. CONCLUSIONS: This study suggests that BTV in high altitude areas of Yunnan is being transmitted by three species of Culicoides, two of which appear to be new to science. This research may be useful in improving understanding of the effects of global warming on arboviral disease epidemiology and further study is important in research into disease control and prevention.


Assuntos
Bluetongue/transmissão , Doenças dos Bovinos/transmissão , Ceratopogonidae/virologia , Insetos Vetores/virologia , Altitude , Animais , Sequência de Bases , Bluetongue/epidemiologia , Vírus Bluetongue/classificação , Vírus Bluetongue/genética , Vírus Bluetongue/isolamento & purificação , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/virologia , Ceratopogonidae/classificação , China/epidemiologia , Código de Barras de DNA Taxonômico/veterinária , DNA Viral/química , DNA Viral/isolamento & purificação , Complexo IV da Cadeia de Transporte de Elétrons/genética , Cabras , Insetos Vetores/classificação , Filogenia , RNA Viral/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Transcrição Reversa , Ruminantes , Estudos Soroepidemiológicos
9.
J Parasitol ; 105(4): 651-658, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31442380

RESUMO

Piroplasmosis is a disease of domestic and wild animals caused by tick-borne protozoa of the genera Theileria and Babesia. Piroplasmosis leads to substantial economic losses in the livestock industry. This disease has been frequently reported in subtropical and tropical regions worldwide. However, information regarding the prevalence of piroplasma in ticks collected from dogs and cattle is lacking in most areas. To assess the potential threat of piroplasmosis in South China, 671 ticks were collected in Guangxi Province. Deoxyribonucleic acid (DNA) was extracted from these ticks to evaluate the presence of piroplasma through a reverse line blot (RLB) hybridization assay using the hypervariable V4 region of the piroplasmic 18S ribosomal ribonucleic acid (r)RNA genes as probes to detect Theileria and Babesia species. The RLB results indicated that 144/671 (21.46%) ticks were infected with piroplasma species belonging to the genera Theileria or Babesia. Theileria buffeli, Babesia vogeli, Theileria annulata, and Theileria luwenshuni were present in the ticks at frequencies of 60/671 (8.94%), 21/671 (3.13%), 6/671 (0.89%), and 6/671 (0.89%), respectively. Mixed infections with 2 or more piroplasma species were present in 8/671 (1.19%) tick samples. The hypervariable V4 region of the piroplasmic 18S rRNA genes from 6 tick DNA samples with single infections was cloned, sequenced, and aligned to related sequences from GenBank. The Theileria and Babesia sequences were analyzed separately. 18S rRNA gene fragment sequences of T. annulata and T. buffeli were compared with previously reported homologous sequences. All 3 B. vogeli sequences examined in this study were grouped into the same cluster and belonged to the same genotype. The present study provides important epidemiological information regarding piroplasmosis occurrence in China. The existence of tick-borne piroplasma likely leads to high infection risks among the local animals in the studied areas.


Assuntos
Vetores Aracnídeos/parasitologia , Babesia/isolamento & purificação , Doenças dos Bovinos/parasitologia , Doenças do Cão/parasitologia , Theileria/isolamento & purificação , Carrapatos/parasitologia , Animais , Babesia/classificação , Babesia/genética , Babesiose/transmissão , Bovinos , Doenças dos Bovinos/transmissão , China , Clonagem Molecular , DNA de Protozoário/isolamento & purificação , Doenças do Cão/transmissão , Cães , Hibridização In Situ/métodos , Hibridização In Situ/veterinária , Filogenia , RNA Ribossômico 18S/genética , Theileria/classificação , Theileria/genética , Theileriose/transmissão , Infestações por Carrapato/parasitologia , Infestações por Carrapato/veterinária
10.
Prev Vet Med ; 170: 104744, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31434021

RESUMO

Bluetongue virus serotype 8 (BTV-8) was reported for the first time in Europe in 2006, causing the largest bluetongue outbreak ever recorded. France was mostly impacted in 2007/09. Trade restrictions were implemented all along. Vaccination became available from 2008: a limited number of doses was first administered in an emergency vaccination campaign, followed by two nationwide compulsory vaccination campaigns in 2009 and 2010. France regained a disease-free status in December 2012, but BTV may have kept circulating undetected as infected herds have been reported again since August 2015. We developed a stochastic dynamic compartmental model of BTV transmission in cattle and sheep to analyze the relative importance of vector active flight and host movements in disease spread, and assess the effectiveness of control measures. We represented BTV transmission both within and between French administrative subdivisions called cantons, during the 2007/09 outbreak and until the end of 2010, when compulsory vaccination was interrupted. Within-canton transmission was vector-borne, and between canton transmission could occur through three contact networks that accounted for movements of: (i) vectors between pastures located at close distance; (ii) cattle and sheep between pastures of the same farm; (iii) traded cattle. We estimated the model parameters by approximate Bayesian computation, using data from the 2007 French outbreak. With this framework, we were able to reproduce the BTV-8 epizootic wave. Host movements between distant pastures of the same farm were found to have a major contribution to BTV spread to disease-free areas, thus raising practical questions about herd management during outbreaks. We found that cattle trade restrictions had been well complied with; without them, the whole French territory would have been infected by winter 2007. The 2008 emergency vaccination campaign had little impact on disease spread as almost half vaccine doses had likely been administered to already immune cattle. Alternatively, establishing a vaccination buffer zone would have allowed a better control of BTV in 2008: limiting its spatial expansion and decreasing the number of infected cattle and sheep. We also showed a major role of compulsory vaccination in controlling the outbreak in 2009 and 2010, though we predicted a possible low-level circulation after the last detection.


Assuntos
Bluetongue/epidemiologia , Bluetongue/transmissão , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/transmissão , Surtos de Doenças/veterinária , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/transmissão , Animais , Teorema de Bayes , Bovinos , França/epidemiologia , Modelos Teóricos , Prevalência , Estudos Soroepidemiológicos , Ovinos
11.
Parasit Vectors ; 12(1): 419, 2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-31455385

RESUMO

BACKGROUND: Babesia bovis is the causal agent of Asiatic redwater, transmitted by the pandemic tick Rhipicephalus (Boophilus) microplus. Disease control may target the tick vector using acaricides or anti-tick vaccines, or the parasite using chemoprophylaxis or anti-parasite vaccines. Current anti-parasite vaccines comprise live blood vaccines using attenuated B. bovis strains. Attenuation is attained by rapid passage that may result in different phenotypes such as reduced virulence, non-transmissibility by the tick vector, inability to sequester in the host (lack of limiting dilution) and limited genetic diversity. Attenuation and phenotypes may be linked to selection of subpopulations during rapid passage. The South African B. bovis S24 vaccine strain comprise a subpopulation that present low virulence, non-transmissibility, lack of limiting dilution phenotype and the presence of a single A558 Bv80 allele. The S24 strain could be co-transmitted with a field strain (05-100) suggesting sexual recombination. The present study investigated the change in phenotype for the S24 vaccine strain during rapid passage and co-transmission. METHODS: Vaccine phenotype change during passage as well as co-transmissibility was monitored using Bv80 allele specific PCR, limiting dilution and Illumina-based genome sequencing. RESULTS: The S24 population could not be rescued from the S16 passage as previously attained suggesting that selection of the S24 vaccine strain was a serendipitous and stochastic event. Passage from S16 to S24 also resulted in loss of the limiting dilution phenotype. Genome sequencing indicated sexual recombination during co-transmission with the 05-100 field strain. Analysis of the recombinant strain indicate that VESA1, smORF and SBP2 family members are present and may be responsible for the limiting dilution phenotypes, while various regions may also be responsible for the tick transmission phenotype. CONCLUSIONS: The molecular basis for tick transmission and limiting dilution phenotypes may be defined in future using selection based on these traits in combination with sexual recombination.


Assuntos
Babesia bovis/genética , Babesiose/parasitologia , Rhipicephalus/parasitologia , Animais , Babesiose/prevenção & controle , Babesiose/transmissão , Bovinos/parasitologia , Doenças dos Bovinos/parasitologia , Doenças dos Bovinos/prevenção & controle , Doenças dos Bovinos/transmissão , Feminino , Genoma de Protozoário , Fenótipo , Vacinas Protozoárias/genética , África do Sul , Vacinas Atenuadas/genética , Virulência , Sequenciamento Completo do Genoma
12.
Vet Res ; 50(1): 60, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31429807

RESUMO

Johne's disease (JD) is a chronic enteritis caused by Mycobacterium avium subsp. paratuberculosis (MAP), with control primarily aimed at preventing new infections among calves. The aim of the current study was to quantify calf-to-calf transmission of MAP among penmates in an experimental trial. Newborn Holstein bull calves (n = 32) were allocated into pens of 4, with 2 inoculated (IN) calves and 2 calves that were contact exposed (CE). Calves were group-housed for 3 months, with frequent collection of fecal and blood samples and tissue collection after euthanasia. The basic reproduction ratio (R0) was estimated using a final size (FS) model with a susceptible-infected model, based on INF-γ ELISA and tissue culture followed by qPCR. In addition, the transmission rate parameter (ß) for new shedding events was estimated using a general linearized method (GLM) model with a susceptible-infected-susceptible model based on culture, followed by qPCR, of fecal samples collected during group housing. The R0 was derived for IN and CE calves separately, due to a difference in susceptibility, as well as differences in duration of shedding events. Based on the FS model, interferon-γ results from blood samples resulted in a R 0 IG of 0.90 (0.24, 2.59) and tissue culture resulted in a R 0 T of 1.36 (0.45, 3.94). Based on the GLM model, the R0 for CE calves to begin shedding (R 0 CE ) was 3.24 (1.14, 7.41). We concluded that transmission of MAP infection between penmates occurred and that transmission among calves may be an important cause of persistent MAP infection on dairy farms that is currently uncontrolled for in current JD control programs.


Assuntos
Doenças dos Bovinos/transmissão , Abrigo para Animais , Mycobacterium avium subsp. paratuberculosis/fisiologia , Paratuberculose/transmissão , Alberta , Criação de Animais Domésticos/métodos , Animais , Bovinos , Masculino
13.
J Vet Med Sci ; 81(10): 1496-1503, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31447461

RESUMO

A surveillance of Culicoides biting midges with light suction traps was conducted in the northern region of Honshu, main island of Japan, during the summers and autumns of 2009 and 2010. A total of 106 trap collections across 37 cattle farms were investigated for the structure and distribution of Culicoides species. Forty-thousand and one hundred forty-nine specimens of Culicoides biting midges were identified at the species level, and ≥19 species were included in the specimens. Culicoides oxystoma, which is a known major vector of Akabane virus (AKAV), appeared not to have expanded in northern Honshu during the surveillance. Of the potential AKAV vectors suggested by a previous laboratory experiment, C. tainanus and C. punctatus widely infested cowsheds across northern Honshu. The AKAV circulation was confirmed by serological surveillance of sentinel cattle in northern Honshu during the summer and autumn of 2010 and, consequently, >200 calves affected by the virus were identified as of spring 2011. Our surveillance demonstrated that C. tainanus and C. punctatus were widely spread and often dominated at cattle farms in/around the seroconverted regions, and our results thus suggest that these species played a critical role in the AKAV transmission in 2010. Because the distribution ranges of C. tainanus and C. punctatus cover almost all of mainland Japan, a potential risk of AKAV transmission might be expected even in areas outside the range of C. oxystoma.


Assuntos
Doenças dos Bovinos/transmissão , Doenças dos Bovinos/virologia , Ceratopogonidae/virologia , Insetos Vetores/virologia , Orthobunyavirus , Animais , Bovinos , Surtos de Doenças , Japão/epidemiologia , Testes Sorológicos
14.
PLoS Comput Biol ; 15(8): e1007184, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31465448

RESUMO

The dynamics of infectious diseases are greatly influenced by the movement of both susceptible and infected hosts. To accurately represent disease dynamics among a mobile host population, detailed movement models have been coupled with disease transmission models. However, a number of different host movement models have been proposed, each with their own set of assumptions and results that differ from the other models. Here, we compare two movement models coupled to the same disease transmission model using network analyses. This application of network analysis allows us to evaluate the fit and accuracy of the movement model in a multilevel modeling framework with more detail than established statistical modeling fitting methods. We used data that detailed mobile pastoralists' movements as input for 100 stochastic simulations of a Spatio-Temporal Movement (STM) model and 100 stochastic simulations of an Individual Movement Model (IMM). Both models represent dynamic movement and subsequent contacts. We generated networks in which nodes represent camps and edges represent the distance between camps. We simulated pathogen transmission over these networks and tested five network metrics-strength, betweenness centrality, three-step reach, density, and transitivity-to determine which could predict disease simulation outcomes and thereby be used to correlate model simulation results with disease transmission simulations. We found that strength, network density, and three-step reach of movement model results correlated with the final epidemic size of outbreak simulations. Betweenness centrality only weakly correlated for the IMM model. Transitivity only weakly correlated for the STM model and time-varying IMM model metrics. We conclude that movement models coupled with disease transmission models can affect disease transmission results and should be carefully considered and vetted when modeling pathogen spread in mobile host populations. Strength, network density, and three-step reach can be used to evaluate movement models before disease simulations to predict final outbreak sizes. These findings can contribute to the analysis of multilevel models across systems.


Assuntos
Febre Aftosa/transmissão , Modelos Biológicos , Migração Animal , Animais , Camarões/epidemiologia , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/transmissão , Biologia Computacional , Simulação por Computador , Epidemias/estatística & dados numéricos , Epidemias/veterinária , Febre Aftosa/epidemiologia , Interações entre Hospedeiro e Microrganismos , Humanos , Análise Espaço-Temporal , Processos Estocásticos
15.
Epidemiol Infect ; 147: e189, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-31364529

RESUMO

Foot and mouth disease (FMD) is a highly contagious and economically important disease of cloven-hoofed animals, which is endemic in Ethiopia. An outbreak follow-up study was undertaken to quantify the transmission parameters of FMD in the crop-livestock mixed (CLM) system and commercial dairy farms in selected areas of northwest Ethiopia. The transmission parameters were quantified using a generalised linear model (GLM) based on a susceptible-infectious-recovered (SIR) epidemic model. The per day average transmission rate between animals was 0.26 (95% CI 0.22-0.32) and 0.33 (95% CI 0.21-0.57) in the CLM system and in the commercial dairy farms, respectively. The average basic reproduction ratio of FMD was 1.68 (95% CI 1.42-2.07) in the CLM system and 1.98 (95% CI 1.26-3.42) in the commercial dairy farms. The medium per day transmission rate and moderate basic reproduction ratio observed in this study indicated that a vaccination coverage needed to stop transmission of the disease in these populations might not be very high.


Assuntos
Doenças dos Bovinos/transmissão , Febre Aftosa/transmissão , Doenças das Cabras/transmissão , Doenças dos Ovinos/transmissão , Animais , Bovinos , Etiópia , Seguimentos , Vírus da Febre Aftosa , Cabras , Ovinos
16.
Biomed Res Int ; 2019: 3794876, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31341897

RESUMO

Leptospirosis is a reemerging zoonosis and ranges in severity from benign to sometimes fatal. In cattle, infection may be responsible for abortion and infertility cases causing economic losses. Humans may be contaminated through direct contact with urine of infected animals or indirectly though interaction with urine-contaminated environment. Many wildlife species living close to cattle, especially commensal rodents may play a role in the transmission of leptospires. Because little is known on the epidemiology of nonmaintenance Leptospira serovars, appropriate management is still limited. On a French farm where human and cattle leptospirosis were detected, the transmission cycle was explored to propose appropriate mitigation measures. For that, commensal rodents present on the farm were trapped and their leptospires carriage was studied by molecular methods. Trapped mice were shown to carry two pathogenic Leptospira species (L. interrogans and L. kirschneri). Since these 2 serogroups were simultaneously detected in the trapped mice and in the cows of this farm, we suspected an initial Leptospira transmission from mice to cows requiring an effective management of mice on this farm. Because resistance to anticoagulant rodenticides due to Vkorc1 mutations has been largely described in rodents and first-generation anticoagulant rodenticides seemed to be inefficient in controlling mice on this farm, susceptibility of these mice to anticoagulants has been characterized by Vkorc1 sequencing. 50% of the trapped mice carried mutations in the Vkorc1 gene leading to severe resistance to first-generation anticoagulants. The management of such mice that are a real sanitary threat can be achieved only by using the most toxic second-generation anticoagulants or nonanticoagulant solutions.


Assuntos
Doenças dos Bovinos/transmissão , Leptospirose/transmissão , Camundongos/microbiologia , Animais , Anticoagulantes , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/microbiologia , Feminino , Humanos , Leptospira/isolamento & purificação , Leptospira interrogans/isolamento & purificação , Leptospirose/epidemiologia , Leptospirose/veterinária , Proteínas de Membrana/genética , Roedores , Rodenticidas , Sorogrupo , Vitamina K Epóxido Redutases/genética , Zoonoses/transmissão
19.
J Infect Public Health ; 12(6): 884-889, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31229413

RESUMO

BACKGROUND: Shiga-toxin producing Escherichia coli (STEC) O26:H11 is the second most common cause of severe diarrhea and hemolytic uremic syndrome worldwide. The implementation of whole genome sequencing (WGS) enhances the detection and in-depth characterization of these non-O157 STEC strains. The aim of this study was to compare WGS to phenotypic serotyping and pulse field gel electrophoresis (PFGE) for characterization of STECO26 strains following a zoonotic outbreak from cattle to humans. METHODS AND RESULTS: This study evaluated seven E. coli strains; two strains isolated from two children with gastrointestinal symptoms and five strains from five calves suspected as the source of infection. Six of these isolates were serotyped phenotypically and by WGS as E. coli O26:H11 while one bovine isolate could be serotyped only by WGS as E. coli O182:H25. Stx1 was detected in two human- and two bovine-isolates using PCR and WGS. Using WGS, all four STECO26 isolates belong to sequence type (ST) 21 while the two stx1 negative E. coli O26 were ST29. All four STECO26 isolates were indistinguishable by PFGE. However, the data generated by WGS linked the two human STECO26 isolates to only one bovine STECO26 strain by having identical high-quality single nucleotide polymorphisms (hqSNPs) and identical virulence factor profiles while the remaining bovine STECO26 isolate differed by 7 hqSNPs and lacked virulence factor toxB. CONCLUSIONS: These data demonstrated that WGS provided significant information beyond traditional epidemiological tools allowing for comprehensive characterization of the STEC. Using this approach, WGS was able to identify the specific source of infection in this study.


Assuntos
Doenças dos Bovinos/epidemiologia , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/veterinária , Sorogrupo , Escherichia coli Shiga Toxigênica/classificação , Sequenciamento Completo do Genoma/métodos , Zoonoses/epidemiologia , Animais , Bovinos , Doenças dos Bovinos/microbiologia , Doenças dos Bovinos/transmissão , Criança , Diarreia/epidemiologia , Diarreia/microbiologia , Diarreia/veterinária , Eletroforese em Gel de Campo Pulsado , Infecções por Escherichia coli/microbiologia , Feminino , Genótipo , Humanos , Masculino , Epidemiologia Molecular/métodos , Tipagem Molecular , Escherichia coli Shiga Toxigênica/genética , Escherichia coli Shiga Toxigênica/isolamento & purificação , Zoonoses/microbiologia , Zoonoses/transmissão
20.
BMC Vet Res ; 15(1): 156, 2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-31109324

RESUMO

BACKGROUND: Bovine respiratory syncytial virus (BRSV) is an important respiratory pathogen worldwide, detrimentally affecting the economy and animal welfare. To prevent and control BRSV infection, further knowledge on virus shedding and transmission potential in individual animals is required. This study aimed to detect viral RNA and infective virions during BRSV infection to evaluate duration of the transmission period and correlation with clinical signs of disease. The outcome of BRSV re-exposure on calves, their housing environment and effect of introduction of sentinel calves was also investigated. A live animal experiment including 10 calves was conducted over 61 days. Initially, two calves were inoculated with a non-passaged BRSV field isolate. Two days later, six naïve calves (EG: Exposed group) were introduced for commingling and four weeks later, another two naïve calves (SG: Sentinel group) were introduced. Seven weeks after commingling, EG animals were re-inoculated. Clinical examination was performed daily. Nasal swabs were collected regularly and analysed for viral RNA by RT-ddPCR, while virus isolation was performed in cell culture. BRSV serology was performed with ELISA. RESULTS: All the EG calves seroconverted and showed clinical signs of respiratory disease. Viral RNA was detected from days 1-27 after exposure, while the infective virus was isolated on day 6 and 13. On day 19, all animals were seropositive and virus could not be isolated. Total clinical score for respiratory signs corresponded well with the shedding of viral RNA. The SG animals, introduced 27 days after exposure, remained negative for BRSV RNA and stayed seronegative throughout the study. Inoculation of the EG calves seven weeks after primary infection did not lead to new shedding of viral RNA or clinical signs of disease. CONCLUSION: Viral RNA was detected in nasal swabs from the calves up to four weeks after exposure. The detection and amount of viral RNA corresponded well with the degree of respiratory signs. The calves were shedding infective virions for a considerable shorter period, and naïve calves introduced after four weeks were not infected. Infected calves were protected from reinfection for at least seven weeks. This knowledge is useful to prevent spread of BRSV.


Assuntos
Doenças dos Bovinos/transmissão , Infecções por Vírus Respiratório Sincicial/veterinária , Vírus Sincicial Respiratório Bovino/fisiologia , Animais , Anticorpos Antivirais/sangue , Bovinos , Doenças dos Bovinos/patologia , Doenças dos Bovinos/virologia , Cavidade Nasal/virologia , RNA Viral/isolamento & purificação , Infecções por Vírus Respiratório Sincicial/patologia , Infecções por Vírus Respiratório Sincicial/transmissão , Infecções por Vírus Respiratório Sincicial/virologia , Vírus Sincicial Respiratório Bovino/isolamento & purificação , Fatores de Tempo , Eliminação de Partículas Virais
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