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Models to assess the risk of introduction of selected animal viral diseases through the importation of live animals as a key part of risk analysis
2021
Gierak, Anna | Śmietanka, Krzysztof
Introduction of an animal viral disease, especially a notifiable disease, into an importing country or region free from the disease may lead to serious epidemiological consequences and economic losses. Trade in live animals is historically considered one of the most important risk pathways. To estimate the magnitude of such risk, the likelihood of a virus’ entry into a country and the consequences of this event should be jointly evaluated. Depending on data availability, the urgency of the problem and the detail level of the objectives, a risk assessment may be conducted in a qualitative, semi-quantitative or quantitative way. The purpose of this review was firstly to provide a brief description of each step of the risk analysis process, with particular emphasis on the risk assessment component, and subsequently to supply examples of different approaches to the assessment of the risk of the introduction of selected animal viral diseases. Based on the reviewed models, the overall likelihood of introduction of particular diseases was generally estimated as low. The output risk value was strongly dependent on the duration of the silent phase of the epidemic in the country of origin. Other parameters with some bearing upon the risk derived from the epidemiological situation in the country of origin and the biosecurity or mitigation measures implemented in the country of destination. The investigated models are universal tools for conducting assessment of the risk of introduction of various animal diseases to any country. Their application may lead to timely implementation of appropriate measures for the prevention of the spread of a disease to another country or region.
显示更多 [+] 显示较少 [-]Selected aspects related to epidemiology, pathogenesis, immunity, and control of African swine fever
2016
Woźniakowski, Grzegorz | Frączyk, Magdalena | Niemczuk, Krzysztof | Pejsak, Zygmunt
African swine fever (ASF) is currently one of the most severe viral infections of domestic pigs, wild boars, and other hosts belonging to Suidae family. ASF is also considered as the most complex and devastating infectious and haemorrhagic disease of swine due to its severe socio-economic impact and transboundary character. ASF it is a notifiable disease and due to the lack of specific treatment and vaccine, the disease can be only limited by the administrative measures comprising wild boar hunting and stamping out of affected pigs. ASF occurred for the first time in Kenya in 1921 while in Europe (Portugal) the virus was detected at the end of the 1950s. In spite of successful eradication of this threat in a number of affected regions, the virus remains endemic in both feral and domestic pigs in Africa and Sardinia. The ‘new era’ of ASF started in 2007 after its re-introduction to Georgia. Following its intensive expansion, the virus spread to other Caucasian countries, including the territory of the Russian Federation. In 2014 the virus reached Ukraine, Belarus, and, consequently, European Union countries: Lithuania, Latvia, Estonia, and Poland. The occurrence of ASF in wild boars and pigs had a severe impact on both epidemiology and economy because of the national and international transport and trade consequences. Up to date, starting from the February 2014, eighty ASF cases in wild boar and three outbreaks in domestic pigs have been diagnosed. Taking into account the diverse rate of spread in Poland, this review aims to present and discuss the current state of knowledge on ASF including its epidemiology, pathology, transmission, and perspectives of control.
显示更多 [+] 显示较少 [-]African swine fever (ASF) and ticks. No risk of tick-mediated ASF spread in Poland and Baltic states
2017
Frant, Maciej | Woźniakowski, Grzegorz | Pejsak, Zygmunt
Infectious diseases of swine, particularly zoonoses, have had a significant influence on nutritional safety and availability of pig meat as high-energy protein product since the time that pigs were domesticated back in the 7ᵗʰ century BC. The main sources of swine infectious diseases include the so-called primary sources (direct infection, i.e. through contact with infected and sick animals) and secondary sources (contaminated meat products, slaughter products, and vectors, including ticks). At present, the most serious epidemiological and economic threat to swine breeding in Europe is African swine fever (ASF). This disease, originally coming from Africa, is incurable and causes death of infected pigs and wild boars during 7−10 days after infection. Among the various factors that influence the spread of ASF, important role is played by ticks from the genus Ornithodoros, mainly from the species Ornithodoros moubata. Research on the ASF indicates that other species of ticks can also transmit the virus to healthy pigs in laboratory conditions. Sylvatic and domestic cycles of ASF virus transmission, which have been described so far, require further studies and updating in order to point the potential new vectors in the Caucasus and Eastern Europe affected by the ASF. Effective methods of control and biosecurity may significantly slow down the spread of ASF, which undoubtedly is a major threat to world pig production and international swine trade.
显示更多 [+] 显示较少 [-]Surveillance for Mycobacterium bovis transmission from domestic cattle to wild ruminants in a Mexican wildlife-livestock interface area
2012
Objective: To assess the prevalence of Mycobacterium bovis infection in cattle and wild ruminants (WRs) in a wildlife-livestock interface area (WLIA) of the Mexican highland plateau. Animals: 24,400 cattle from 793 herds (including 17,351 commercially slaughtered cattle) and 142 WRs (110 white-tailed deer [Odocoileus virginianus], 20 red deer [Cervus elaphus], and 12 North American elk [Cervus canadensis]) harvested via controlled hunting. Procedures: Cattle were serially tested for M bovis infection via caudal fold tuberculin and comparative cervical tuberculin tests during field surveillance. Carcasses of cattle and WRs were inspected for gross lesions; samples suggestive of tuberculosis were analyzed via histologic evaluation and mycobacterial culture (HMC). A PCR assay to detect Mycobacterium tuberculosis complex organisms was performed to confirm positive results of HMC. Results: WRs had inflammatory lesions in lungs and lymph nodes, although HMC results did not indicate M bovis infection. Eight cattle had positive results for both tuberculin tests, and 31 had positive results for HMC of grossly detected lesions; all were from 7 herds, and ≥ 1 cow in each herd had positive PCR assay results. These 7 herds were depopulated; adjacent herds and herds related via commerce were quarantined. Calculated true prevalence of M bovis infection was 0.86% (95% confidence interval, 0.24% to 1.49%) in cattle; M bovis was not detected in any WRs. Conclusions and Clinical Relevance: M bovis infection was present in cattle. Although transmission to WRs in this WLIA was not detected, diagnosis and prevention activities should be implemented and consolidated to prevent potential M bovis transmission between cattle and WRs.
显示更多 [+] 显示较少 [-]Evaluation of a Campylobacter fetus subspecies venerealis real-time quantitative polymerase chain reaction for direct analysis of bovine preputial samples
2012
Chaban, Bonnie | Chu, Shirley | Hendrick, Steven | Waldner, Cheryl | Hill, Janet E.
The detection and subspeciation of Campylobacter fetus subsp. venerealis (CFV) from veterinary samples is important for both clinical and economic reasons. Campylobacter fetus subsp. venerealis is the causative agent of bovine genital campylobacteriosis, a venereal disease that can lead to serious reproductive problems in cattle, and strict international regulations require animals and animal products to be CFV-free for trade. This study evaluated methods reported in the literature for CFV detection and reports the translation of an extensively tested CFV-specific polymerase chain reaction (PCR) primer set; including the VenSF/VenSR primers and a real-time, quantitative PCR (qPCR) platform using SYBR Green chemistry. Three methods of preputial sample preparation for direct qPCR were evaluated and a heat lysis DNA extraction method was shown to allow for CFV detection at the level of approximately one cell equivalent per reaction (or 1.0 × 10(3) CFU/mL) from prepuce. The optimized sample preparation and qPCR protocols were then used to evaluate 3 western Canadian bull cohorts, which included 377 bulls, for CFV. The qPCR assay detected 11 positive bulls for the CFV-specific parA gene target. DNA sequence data confirmed the identity of the amplified product and revealed that positive samples were comprised of 2 sequence types; one identical to previously reported CFV parA gene sequences and one with a 9% sequence divergence. These results add valuable information towards our understanding of an important CFV subspeciation target and offer a significantly improved format for an internationally recognized PCR test.
显示更多 [+] 显示较少 [-]Brazilian donkey slaughter and exports from 2002 to 2019
2021
Mariana Bombo Perozzi Gameiro | Vanessa Theodoro Rezende | Adroaldo José Zanella
The international demand for donkeys has increased sharply in recent years, motivated by China’s growing interest in producing ejiao (a traditional medicine made from donkey skin) and, in a smaller proportion, donkey meat. Since the Chinese donkey population dropped by 75.4% in the past 25 years, the country has searched for supply in the international market, mainly in Africa and South America. Aiming to understand the participation of Brazil in this scenario, this paper presents and discusses official data on donkey slaughter and donkey meat and skin exports in Brazil from 2002 to 2019. After the recent news reports of donkey trade-related mistreatment in the Brazilian Northeast, the issue has attracted attention from public authorities, the media, and civil society, but it lacked a quantitative description that could give a tangible dimension to the situation. The interpretation of these data is made with the collaboration of qualitative research methods, emphasizing some aspects of human-animal relations.
显示更多 [+] 显示较少 [-]Analysis of the cattle trade network in the state of Mato Grosso, Brazil
2020
Rísia Lopes Negreiros | José Henrique Hildebrand Grisi-Filho | Ricardo Augusto Dias | Fernando Ferreira | José Soares Ferreira Neto | Raul Ossada | Marcos Amaku
We characterized the network of cattle movements in Mato Grosso, Brazil—a state responsible for a significant amount of Brazilian beef exports. In this analysis, we were particularly interested in the importance of slaughterhouses in the network of cattle movements, in the characteristics of the trade for different purposes (especially for reproduction, fattening, and slaughter), and about the importance of the main traders. We found that the median distance of all movements was 79.0 km, with an interquartile range between 37.2 and 163.2 km, which suggests a relatively short-range trade pattern; roughly 20% of the premises purchasing more animals were responsible for 95% of the animals purchased and 20% of the premises selling more animals were responsible for 86% of the animals sold, indicating the importance of the cattle trade hubs. Fitting the degree distribution using a power-law distribution, we obtained a scaling parameter of 2.59, indicating that the cattle movement network of Mato Grosso is less dense than other observed cattle movement networks. The networks for fattening, reproduction, and slaughtering only comprised 73%, 56%, and 25% of all nodes and 52%, 30%, and 17% of all edges, respectively; and slaughterhouses had the highest in-degrees and total degrees, followed by markets and farms, playing the role of main cattle trade hubs. Therefore, slaughterhouses are potentially useful as surveillance points to detect cases, and controlling important trader premises may optimize the use of resources for controlling diseases.
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