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2.
Prev Vet Med ; 224: 106115, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38219433

ABSTRACT

Bovine brucellosis, primarily caused by Brucella abortus, severely affects both animal health and human well-being. Accurate diagnosis is crucial for designing informed control and prevention measures. Lacking a gold standard test makes it challenging to determine optimal cut-off values and evaluate the diagnostic performance of tests. In this study, we developed a novel Bayesian Latent Class Model that integrates both binary and continuous testing outcomes, incorporating additional fixed (parity) and random (farm) effects, to calibrate optimal cut-off values by maximizing Youden Index. We tested 651 serum samples collected from six dairy farms in two regions of Henan Province, China with four serological tests: Rose Bengal Test, Serum Agglutination Test, Fluorescence Polarization Assay, and Competitive Enzyme-Linked Immunosorbent Assay. Our analysis revealed that the optimal cut-off values for FPA and C-ELISA were 94.2 mP and 0.403 PI, respectively. Sensitivity estimates for the four tests ranged from 69.7% to 89.9%, while specificity estimates varied between 97.1% and 99.6%. The true prevalences in the two study regions in Henan province were 4.7% and 30.3%. Parity-specific odds ratios for positive serological status ranged from 1.2 to 2.2 for different parity groups compared to primiparous cows. This approach provides a robust framework for validating diagnostic tests for both continuous and discrete tests in the absence of a gold standard test. Our findings can enhance our ability to design targeted disease detection strategies and implement effective control measures for brucellosis in Chinese dairy farms.


Subject(s)
Brucellosis, Bovine , Brucellosis , Cattle Diseases , Female , Humans , Cattle , Animals , Brucella abortus , Bayes Theorem , Latent Class Analysis , Sensitivity and Specificity , Agglutination Tests/veterinary , Brucellosis/epidemiology , Brucellosis/veterinary , Enzyme-Linked Immunosorbent Assay/veterinary , Brucellosis, Bovine/diagnosis , Brucellosis, Bovine/epidemiology , Antibodies, Bacterial , Serologic Tests/veterinary
3.
Math Biosci ; 367: 109125, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38072124

ABSTRACT

Avian influenza scare is a human psychological factor that asserts both positive and negative effects on the transmission of zoonotic avian influenza. In order to study the dichotomous effect of avian influenza scare on disease transmission, taking H7N9 avian influenza as a typical case, a two-patch epidemic model is proposed. The global dynamics and the threshold criteria are established by LaSalle invariant principle and the theory of asymptotic autonomous system. To mitigate the negative effects and curb illegal poultry trade, a game-theoretic model is adopted to explore the optimal policy of culling subsidies to reasonably compensate stakeholders for their economic losses resulting from the scare. The optimal policy of culling subsidy is found to heavily depend on the penalty of illegal poultry trade, the stakeholders' income, the intensity of control measures, and the prevalence level of the disease. The negative effect of avian influenza scare on disease transmission is considerably more significant than the positive effect. In order to avoid a widespread outbreak of zoonotic avian influenza across the region, a comprehensive national global control strategy is essential and effective, even in the presence of the negative effect of the avian influenza scare.


Subject(s)
Influenza A Virus, H7N9 Subtype , Influenza in Birds , Influenza, Human , Animals , Humans , Influenza, Human/epidemiology , Disease Outbreaks/prevention & control , Poultry , China/epidemiology
5.
J Proteome Res ; 22(9): 2985-2994, 2023 09 01.
Article in English | MEDLINE | ID: mdl-37531193

ABSTRACT

Chimeric antigen receptor (CAR)-modified T cells have demonstrated remarkable efficacy in treating B-cell leukemia. However, treated patients may potentially develop side effects, such as cytokine release syndrome (CRS), the mechanisms of which remain unclear. Here, we collected 43 serum samples from eight patients with B-cell acute lymphoblastic leukemia (B-ALL) before and five time points after CD19-specific CAR-T cell treatment. Using TMTpro 16-plex-based quantitative proteomics, we quantified 1151 proteins and profiled the longitudinal proteomes analysis of each patient. Seven days after therapy, we found the most dysregulated inflammatory proteins. Lipid metabolism proteins, including APOA1, decreased after therapy, reached their minimum after 7 days, and then gradually recovered. Hence, APOA1 has been selected as a potential biomarker of the CRS disease progression. Furthermore, we identified CD163 as a potential biomarker of CRS severity. These two biomarkers were successfully validated using targeted proteomics in an independent cohort. Our study provides new insights into CAR-T cell therapy-induced CRS. The biomarkers we identified may help develop targeted drugs and monitoring strategies.


Subject(s)
Precursor Cell Lymphoblastic Leukemia-Lymphoma , Receptors, Chimeric Antigen , Humans , Receptors, Chimeric Antigen/therapeutic use , Proteomics , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Biomarkers , Antigens, CD19 , Cell- and Tissue-Based Therapy
6.
One Health ; 16: 100513, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37363255

ABSTRACT

Streptococcus suis (S. suis) is one of the most important pathogens affecting pig production worldwide. It can be also transmitted to human through the behaviors of eating undercooked pork or slaughtering sick pigs. A meta-analysis was conducted to estimate the prevalence across different geographical areas in China. Forty-three articles were included and distributed in 22 provinces of China. The prevalence of S. suis infection in pigs varied from 4.2% to 93.7%, with a summary estimate of 40.8% (95%CI, 32.9-48.6%). Six provinces, classified as frequent outbreaks in human cases, had a higher prevalence (52.7%, 95%CI: 43.7-61.6%) than other provinces (36.0%, 95%CI: 27.0-44.9%). Jiangsu province had the highest prevalence with 73.1% (95%CI: 70.42-75.68%), followed by Hunan (59.64%, 95%CI: 55.83-63.37%), Shanxi (55.56%, 95%CI: 47.05-63.83%), and Guangxi (50.55%, 95%CI: 49.45-51.64%). The prevalence has been decreasing gradually, from 47.6% (95%CI: 38.1-57.1%) before 2010, then dropped to 39.1% (95%CI: 25.5-52.8%) during 2011-2015, and reached the lowest in recent five years (2016-2020), with 34.3% (95%CI: 23.1-45.4%). The study findings showed that S. suis was presented in pig populations of most provinces of China, which indicated that effective control measures in pigs should be implemented. Our results also provided solid evidence for the early warning and prevention of human S. suis infection in China, which would mitigate the risk to humans.

7.
Ecol Evol ; 12(10): e9409, 2022 Oct.
Article in English | MEDLINE | ID: mdl-36254297

ABSTRACT

Rattus norvegicus and Rattus tanezumi are dominant species of Chinese house rats, but the colonization and demographic history of two species in China have not been thoroughly explored. Phylogenetic analyses with mitochondrial DNA including 486 individuals from 31 localities revealed that R. norvegicus is widely distributed in China, R. tanezumi is mainly distributed in southern China with currently invading northward; northeast China was the natal region of R. norvegicus, while the spread of R. tanezumi in China most likely started from the southeast coast. A total of 123 individuals from 18 localities were subjected to 2b-RAD analyses. In neighbor-joining tree, individuals of R. tanezumi grouped into geographic-specific branches, and populations from southeast coast were ancestral groups, which confirmed the colonization route from southeast coast to central and western China. However, individuals of R. norvegicus were generally grouped into two clusters instead of geographic-specific branches. One cluster comprised inland populations, and another cluster included both southeast coast and inland populations, which indicated that spread history of R. norvegicus in China was complex; in addition to on-land colonization, shipping transportation also have played great roles. ADMIXTURE and principal component analyses provided further supports for the colonization history. Demographic analyses revealed that climate changes at ~40,000 to 18,000 years ago and ~4000 years ago had led to population declines of both species; the R. norvegicus declined rapidly while the population of R. tanezumi continuously expanded since ~1500 years ago, indicating the importance of interspecies' competition in their population size changes. Our study provided a valuable framework for further investigation on phylogeography of two species in China.

8.
Bioresour Technol ; 365: 128179, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36283669

ABSTRACT

Glycerol is an ideal co-substrate for xylitol production with Kluyveromyces marxianus. This study demonstrated that K. marxianus catabolizes glycerol through the Gut1-Gut2 pathway instead of the previously speculated NADPH-dependent Gcy1-Dak1 pathway using the transient clustered regularly interspaced short palindromic repeats/ CRISPR-associated protein 9 (CRISPR/Cas9) system. Additionally, Utr1p was demonstrated to mediate NADPH generation through NADH phosphorylation. YZB392, which was constructed by integrating Utr1 into the Ypr1 site in the strain overexpressing NcXyl1 and CiGxf1 and harboring disrupted Xyl2, exhibited enhanced glycerol utilization for xylitol production (from 2.50- to 3.30- g/L after consuming 1 g/L glycerol). Fed-batch fermentation at 42 °C with YZB392 yielded 322.07 g/L xylitol, which is the highest known xylitol titer obtained via biological method. Feeding crude glycerol, xylose mother liquor, and corn steep liquor powder into a bioreactor resulted in the production of 235.69 g/L xylitol. This study developed a platform for xylitol production from industrial by-products.


Subject(s)
Kluyveromyces , Xylitol , Glycerol/metabolism , CRISPR-Associated Protein 9/metabolism , NADP/metabolism , Temperature , Kluyveromyces/genetics , Kluyveromyces/metabolism , Xylose/metabolism , Fermentation
9.
Vector Borne Zoonotic Dis ; 22(7): 391-396, 2022 07.
Article in English | MEDLINE | ID: mdl-35736787

ABSTRACT

Background: Pseudorabies virus (PRV) is a common pathogen found in pigs. The pathogenicity of PRV in humans is under researched and there are few confirmed cases of PRV infections in humans, which has led to a lack of clinical consensus. Methods: We presented a case of viral encephalitis caused by PRV in China. We performed a systematic review of the literature to investigate the clinical features and prognosis of PRV encephalitis and included 12 patients with PRV encephalitis. Results: All the patients had a history of direct or indirect contact with living pigs or pork before the onset of the disease, accompanied by prodromal symptoms, such as fever and headache. They presented with a series of lesions involving the central nervous system (CNS) and respiratory system, such as acute encephalitis syndrome, respiratory failure, retinitis, or endophthalmitis. Conclusions: The differential diagnosis of an acute attack of CNS infection should include PRV encephalitis, which should be diagnosed by a head magnetic resonance imaging (MRI), fundus examination, and cerebrospinal fluid next-generation sequencing. Intravenous immunoglobulin, glucocorticoid, antiviral, and symptomatic support treatment should be administered as early as possible to improve the prognosis.


Subject(s)
Encephalitis , Herpesvirus 1, Suid , Pseudorabies , Swine Diseases , Animals , China , Encephalitis/veterinary , Herpesvirus 1, Suid/genetics , Humans , Pseudorabies/diagnosis , Pseudorabies/pathology , Swine
10.
Sensors (Basel) ; 22(6)2022 Mar 17.
Article in English | MEDLINE | ID: mdl-35336496

ABSTRACT

Thermal compensation control can correct errors caused by the thermal deformation of phased array antenna (PAA) panels. Thermal deformation of the panel is needed to calculate the compensation value. While the PAA is working, thermal deformation is unconditional to measure, but predicting it by temperature is feasible. However, thermal deformation is also affected by other factors, such as the structural shape, assembly method, and material parameters, and it is difficult to measure these parameters of PAA because of the complex structure. In contrast, the measurement method of the temperature and thermal deformation of the PAA in the laboratory is much easier. Therefore, a comprehensive influence parameters (CIPs)-finite element method (FEM) method was proposed in this study, it can extract the influence of above parameters on thermal deformation from temperature and thermal deformation measurement data and build a thermal deformation prediction model. Experiments have verified that the CIPs-FEM can greatly reduce the difficulty of thermal deformation modeling and have a high prediction accuracy.

11.
Appl Opt ; 61(4): 1057-1067, 2022 Feb 01.
Article in English | MEDLINE | ID: mdl-35201079

ABSTRACT

In this paper, a joint communication interference integration signal waveform is proposed to satisfy the need of electronic system integration in civil and military uses, and mitigate the tension of spectrum resource. We design the system structure of the integrated signal model and propose the communication receiving processing flow of the integrated system. We utilize the dense false-target jamming style to raise the constant false alarm rate detection threshold via the delay superposition of multiple groups of frequency modulation (FM) slope mismatch jamming signals, which can play a role in protecting our target from being detected. Furthermore, linear frequency modulation (LFM) signals with different FM slopes and Doppler frequencies are obtained via the modulation mapping of communication data; thus, a single LFM signal can carry n bit data. Through correlation processing and frequency detection, code sequence information can be obtained to achieve communication function. The simulation results show that the integrated signal has the effect of shielding and jamming the pulse compression radar. Moreover, the system has a better bit error rate and a high communication rate, which can ensure that the communication task of sending accurate instructions is completed while implementing effective interference.

12.
Sensors (Basel) ; 22(1)2022 Jan 05.
Article in English | MEDLINE | ID: mdl-35009936

ABSTRACT

The data volume and computation task of MIMO radar is huge; a very high-speed computation is necessary for its real-time processing. In this paper, we mainly study the time division MIMO radar signal processing flow, propose an improved MIMO radar signal processing algorithm, raising the MIMO radar algorithm processing speed combined with the previous algorithms, and, on this basis, a parallel simulation system for the MIMO radar based on the CPU/GPU architecture is proposed. The outer layer of the framework is coarse-grained with OpenMP for acceleration on the CPU, and the inner layer of fine-grained data processing is accelerated on the GPU. Its performance is significantly faster than the serial computing equipment, and satisfactory acceleration effects have been achieved in the CPU/GPU architecture simulation. The experimental results show that the MIMO radar parallel simulation system with CPU/GPU architecture greatly improves the computing power of the CPU-based method. Compared with the serial sequential CPU method, GPU simulation achieves a speedup of 130 times. In addition, the MIMO radar signal processing parallel simulation system based on the CPU/GPU architecture has a performance improvement of 13%, compared to the GPU-only method.


Subject(s)
Algorithms , Radar , Computer Graphics , Computer Simulation , Signal Processing, Computer-Assisted
13.
Prev Vet Med ; 200: 105580, 2022 Mar.
Article in English | MEDLINE | ID: mdl-35032782

ABSTRACT

China launched a H7N9 vaccination program in poultry, starting from the Guangxi and Guangdong provinces in July 2017, followed by other provinces in September 2017, as a response to a steep increase of H7N9 influenza human infections from September 2016. Since then, H5-H7 bivalent vaccine has been used in the nationwide avian influenza compulsory vaccination program to replace the existing H5N1 vaccine. However, the economic returns of the H7N9 vaccination program in China have never been adequately assessed. This study was designed to evaluate the economic value of the H7N9 vaccination program in Guangxi by assessing the benefits and costs of the program compared to not vaccinating against H7N9. A benefit-cost analysis (BCA) was undertaken to evaluate the adoption of a vaccination program against H7N9 in each of three consecutive years from July 2017 to June 2020 with the baseline scenario (the absence of H7N9 vaccination in the 12-month period July 2016 to June 2017). Both animal and public health perspectives were included in the BCA framework and took account of both the private and public sectors. Benefit-Cost Ratio (BCR) of the three-year H7N9 vaccination program was 18.6 (90 %PI: 15.4; 21.8), and total Net Present Values reached to CNY 1.63 billion (90 %PI: 1.37 billion; 1.89 billion). The extra revenue generated by the yellow broiler industry comprised 93.8 % of the total benefits after adoption of H7N9 vaccination program in Guangxi. While cost-savings in public health and animal health expenditure avoided were 3.6 % and 2.6 %, respectively. Total costs arising from adoption of the revised vaccination program over the three years were CNY 12.46 million (90 %PI: 11.49 million; 14.14 million), CNY 34.87 million (90 %PI: 31.88 million; 40.06 million), and CNY 44.28 million (90 %PI: 39.66 million; 52.27 million), respectively. Sensitivity analysis found the yellow broiler wholesale prices contributed 97.7 % of the variance of the total NPV of three vaccination years. The study results demonstrate the significant economic advantage of implementing a vaccination program against H7N9 in Guangxi. It also offers a new set of evidence to China's H7N9 vaccination policy and debates around economic values of conducting routine avian influenza vaccination.


Subject(s)
Influenza A Virus, H5N1 Subtype , Influenza A Virus, H7N9 Subtype , Influenza in Birds , Influenza, Human , Animals , Chickens , China , Cost-Benefit Analysis , Humans , Influenza in Birds/prevention & control , Influenza, Human/prevention & control , Poultry , Vaccination/veterinary
14.
Transbound Emerg Dis ; 69(4): e775-e787, 2022 Jul.
Article in English | MEDLINE | ID: mdl-34693647

ABSTRACT

Most Chinese provinces have a daily-updated database of live animal movements; however, the data are not efficiently utilized to support interventions to control H7N9 and other avian influenzas. Based on official records, this study assessed the spatio-temporal patterns of live broilers moved out of and within Guangxi in 2017. The yearly and monthly networks were analyzed for inter- and intra-provincial movements, respectively. Approximately 200,000 movements occurred in 2017, involving the transport of 200 million live broilers from Guangxi. Although Guangxi exported to 24 out of 32 provinces of China, 95% of inter-provincial movements occurred with three bordering provinces. Within Guangxi, counties were highly connected through the live broiler movements, creating conditions for rapid virus spreading throughout the province. Interestingly, a peak in movements during the Chinese Lunar New Year celebrations, late January in 2017, was not observed in this study, likely due to H7N9-related control measures constraining live bird trading. Both intra- and inter-provincial movements in March 2017 were significantly higher than in other months of that year, suggesting that dramatic price changes may influence the movement's network and reshape the risk pathways. However, despite these variations, the same small proportion of counties (less than 20%) exporting/importing more than 90% of inter- and intra-provincial movements remains the same throughout the year. Interventions, particularly surveillance and improving biosecurity, targeted to those counties are thus likely to be more effective for avian influenza risk mitigation than implemented indiscriminately. Additionally, simulations further demonstrated that targeting counties according to their degree or betweenness in the movement network would be the most efficient way to limit disease transmission via broiler movements. The study findings provide evidence to support the design of risk-based control interventions for H7N9 and all other avian influenza viruses in broiler value chains in Guangxi.


Subject(s)
Influenza A Virus, H7N9 Subtype , Influenza in Birds , Animals , Chickens , China/epidemiology , Influenza in Birds/epidemiology , Influenza in Birds/prevention & control , Poultry
15.
Transbound Emerg Dis ; 69(4): e646-e658, 2022 Jul.
Article in English | MEDLINE | ID: mdl-34655504

ABSTRACT

Since the outbreak of African swine fever (ASF) in Shengyang, it has continued spreading in China. In the early stage of the epidemic, multi-point and concentrated outbreaks were mainly in the swill feeding areas. In this paper, we developed compartmental models to investigate the transmission of ASF in several raising units including Guquan, Jinba and Liancheng. Using the data collected from these three infected premises, we calibrated the models to estimate that the average incubation period was between 8 and 11 days, the onset period was about 2-3 days and the basic reproductive number was about 4.83-11.90. We also estimated the infection on the day before culling to be 45.24% (Guquan), 89.20% (Jinba) and 16.35% (Liancheng), respectively. The infection rate of Guquan could reach about 74.8% if culling were postponed by 2 days. We found that the infection was significantly higher than the morbidities (22.11% (Guquan), 49.35% (Jinba) and 12.94% (Liancheng)) calculated by actual statistical data. Besides, we simulated and compared the control effect of stopping transport, disinfecting, stopping swill and culling. Our findings suggest that any single measure was not enough to prevent the spread of ASF on a regional level but the combined measures is the key. Under the current situation, fully culling was recognized as most effective in controlling the epidemic, despite the culling of uninfected pigs.


Subject(s)
African Swine Fever Virus , African Swine Fever , Swine Diseases , Animals , Basic Reproduction Number/veterinary , China/epidemiology , Disease Outbreaks/veterinary , Swine , Swine Diseases/epidemiology
16.
Transbound Emerg Dis ; 69(4): e224-e235, 2022 Jul.
Article in English | MEDLINE | ID: mdl-34379893

ABSTRACT

In response to a sudden increase in H7N9 human infections, China introduced an H5/H7 bivalent inactivated vaccine for poultry in Guangxi and Guangdong provinces in July 2017, which subsequently became integrated into the existing compulsory national H5N1 vaccination programme from September 2017. Although the vaccination programme effectively reduced H7N9 infections in humans and poultry, there are ongoing arguments against continuing this long-term vaccination. These discussions have drawn policymakers to think about the possibility of stopping routine vaccination for H7N9 avian influenza viruses (AIVs) in China; however, they have not considered the poultry industry stakeholders' practices on and attitudes towards this vaccination. This study investigated H7N9 vaccination practices in the yellow broiler industry in Guangxi and stakeholders' attitudes on H7N9 vaccination, using a mixed methods design. The study found H7N9 vaccination was well adopted in the yellow broiler industry in Guangxi regardless of the source of the vaccines. Most stakeholders believed vaccination was the best measure to control H7N9 and H5N1 AIVs, and they showed a strong willingness to continue with vaccination even without government subsidies or freely provided vaccines. The motivations by stakeholders for using vaccines to control H7N9 and H5N1 were different due to the epidemiological differences between the two strains. Understanding poultry industry stakeholders' practices and attitudes on H7N9 vaccination has important practical implications in planning vaccination policies, particularly when considering the possibility of vaccination withdrawal.


Subject(s)
Influenza A Virus, H5N1 Subtype , Influenza A Virus, H7N9 Subtype , Influenza Vaccines , Influenza in Birds , Influenza, Human , Animals , Chickens , China , Humans , Influenza in Birds/prevention & control , Influenza, Human/prevention & control , Poultry , Vaccination/veterinary
17.
Cell Mol Biol (Noisy-le-grand) ; 68(9): 102-108, 2022 Sep 30.
Article in English | MEDLINE | ID: mdl-36905267

ABSTRACT

The neuroprotection of acute cerebral infarction (ACI) model by edaravone dexborneol (ED)-mediated Keap1-Nrf2/ARE signal pathway was investigated. Sham operation was set as a control to prepare the ACI model with cerebral artery occlusion. The abdominal cavity was injected with edaravone (ACI+Eda group) and ED (ACI+ED group). Then, neurological deficit scores, cerebral infarct volume, oxidative stress ability, inflammatory reaction level, and the status of the Keap1-Nrf2/ARE signal pathway of rats in all groups were explored. It was demonstrated that the neurological deficit score and cerebral infarct volume of rats in the ACI group apparently increased versus those in the Sham group (P<0.05), suggesting that the ACI model was successfully prepared. Versus those in the ACI group, the neurological deficit score and cerebral infarct volume of rats in the ACI+Eda and ACI+ED groups decreased. In contrast, the activity of cerebral oxidative stress superoxide dismutase (SOD) and glutathione-peroxidase (GSH-Px) increased. Malondialdehyde (MDA) and the expressions of cerebral inflammation indicators (interleukin (IL)-1ß, IL-6, and tumor necrosis factor-α messenger ribonucleic acid (TNF-α mRNA)) and cerebral Keap1 reduced. The expressions of Nrf2 and ARE increased (P<0.05). Versus those in the ACI+Eda group, all indicators of rats in the ACI+ED group were improved more apparently and were more similar to those in the Sham group (P<0.05). The above findings suggested that both edaravone and ED could mediate Keap1-Nrf2/ARE signal pathway to play a neuroprotective role in ACI. Versus edaravone, ED improved ACI oxidative stress and inflammatory reaction level and played a neuroprotective role more apparently.


Subject(s)
Brain Ischemia , NF-E2-Related Factor 2 , Rats , Animals , Edaravone , NF-E2-Related Factor 2/metabolism , Kelch-Like ECH-Associated Protein 1/metabolism , Rats, Sprague-Dawley , Neuroprotection , Cerebral Infarction/pathology , Oxidative Stress , Inflammation
18.
J Theor Biol ; 526: 110798, 2021 10 07.
Article in English | MEDLINE | ID: mdl-34097915

ABSTRACT

African swine fever virus (ASFV) leads to a highly contagious, lethal and economically devastating disease among pigs. Since no effective treatment for the disease, it is crucial to investigate its transmission mechanism and control strategies in large-scale pig farms. We first established a toy model to explore ASFV spread in one pig unit. Then a switching patch model was developed to capture its spread from one initial epidemic pig house consecutively to others, even the whole farm. Assessing innocent culling rates of three large-scale epidemic pig farms in Jiangsu Province showed that it is unnecessary to slaughter all pigs in the farms compulsively. Then we explored how the disinfection and fixation of employees impact ASFV spread in the farms. To control ASFV, we can block or slow down its spreading by improving the efficiency of disinfection and decreasing employee population to some extend. We can also shrink potential areas to be infected by properly improving the matching refinement degree among employees and houses. Some essential requirements for large-scale pig farms are presented to reduce their ASFV spreading risk, which can be helpful for animal health authorities in establishing regulation to standardize large-scale pig farms.


Subject(s)
African Swine Fever Virus , African Swine Fever , Epidemics , African Swine Fever/epidemiology , African Swine Fever/prevention & control , Animals , Disease Outbreaks/prevention & control , Disease Outbreaks/veterinary , Farms , Swine
19.
Prev Vet Med ; 190: 105328, 2021 May.
Article in English | MEDLINE | ID: mdl-33765448

ABSTRACT

Yellow broilers are the primary source of poultry consumption in China and the predominant trade of live poultry. However, knowledge of the value chain is limited, which is vital evidence for the effective control of H7N9 and other zoonotic avian influenzas. The aim of the study was to map the yellow broiler value chain in Guangxi Zhuang Autonomous Region, China and investigate its governance structure and practices relevant to the risk of H7N9 transmission. A value chain analysis was conducted in five areas of Guangxi from May to August 2018. To map the value chain, three focus group discussions (FGDs) were conducted and stakeholders, products and premises involved and their interactions were identified. Then, 55 key informant interviews (KIIs) collected qualitative data on stakeholders' profile, practices and interactions with other stakeholders and rules/norms that exist along the value chain. On-site observations were also carried out at different types of premises along the value chain to complement and validate findings of KIIs and FGDs. Participants were also asked to provide proportional estimates of each component in the value chain where possible. The qualitative data from FGDs, KIIs and on-site observations were analysed to create stakeholder profiles and a diagram of product flows and stakeholders' interactions. Thematic analysis was used to identify the governance structure of the value chains and practices relevant to the risk of H7N9 transmission. The stakeholders and premises involved in Guangxi yellow broiler production, wholesale and retail were described, as well as their interactions. Contract farming is extensively adopted in Guangxi; consequently yellow broiler grower companies are the dominant stakeholders. The trading platform was identified as a key premise linking farms and live bird markets. The thematic analysis highlighted poor biosecurity practices in different premises along the value chain, which was supported by on-site observations. The operation of trading platforms reported in this study presents a disease risk but is not considered in the current H7N9 control programs. The study suggested that biosecurity management gaps need to be addressed through government-industry partnerships that require engagement with private stakeholders in the planning and implementation of H7N9 control strategies incentivising participation of grower companies, wholesalers and retailers.


Subject(s)
Influenza A Virus, H7N9 Subtype , Influenza in Birds , Agriculture , Animals , Chickens , China , Commerce , Influenza in Birds/epidemiology , Influenza in Birds/prevention & control , Poultry
20.
J Theor Biol ; 512: 110558, 2021 03 07.
Article in English | MEDLINE | ID: mdl-33346020

ABSTRACT

In China, foot-and-mouth disease (FMD) serotype O remains prevalent, and its main host is pigs. Infected but undiscovered pigs can carry foot-and-mouth disease virus (FMDV) for a longtime. And, the virus can spread among farms through pig trade. Although individual vaccination at least 2 times a year and monthly monitoring disease and culling all individual in same group for pigs are adopted vigorously in China, the epidemic remains prevalent. Therefore, in this paper, based on these propagation characteristics and control measures of the epidemic in China, we take the pig farms as research individuals, the trade among farms as transmission routes to establish a dynamic model with nonlinear incidence. In addition, we use this model to assess the impact of trade and transport of pigs among farms on the spread of foot-and-mouth disease virus (FMDV), and to assess the effect of the immunization, monitoring and culling adopted presently in China on the control of the epidemic. By the dynamical analysis of the model, it is found that there will appear backward branching under some conditions, which means that there are two spreading thresholds for the disease, and the disease development trend is also related to the current epidemic situation. Besides, we give the threshold conditions of key parameters to control the spread of FMD. By carrying out data fitting and parameter estimation, we confirm the model rationality, and give four evaluation indexes: the basic reproduction number R0 of FMD serotype O in China, the value of the infected farms at the equilibria, annual probability of a susceptible farm being infected and annual transmission intensity of an infected farm. By carrying out the sensitivity analysis of key parameters on four evaluation indexes, the effect of parameters on the spread of the disease can be intuitively observed. All these can provide a theoretical basis for understanding of the trading-based transmission mechanism, control and prevention of foot-and-mouth disease in pigs in China.


Subject(s)
Foot-and-Mouth Disease Virus , Foot-and-Mouth Disease , Animals , Basic Reproduction Number , China/epidemiology , Disease Outbreaks , Foot-and-Mouth Disease/epidemiology , Foot-and-Mouth Disease/prevention & control , Risk Factors , Swine
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