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1.
We explored observed risk factors and drivers of infection possibly associated with African swine fever (ASF) epidemiology in Uganda. Representative sub-populations of pig farms and statistics were used in a case-control model. Indiscriminate disposal of pig viscera and waste materials after slaughter, including on open refuse dumps, farm-gate buyers collecting pigs and pig products from within a farm, and retention of survivor pigs were plausible risk factors. Wire mesh-protected windows in pig houses were found to be protective against ASF infection. Sighting engorged ticks on pigs, the presence of a lock for each pig pen and/or a gate at the farm entrance were significantly associated with infection/non-infection; possible explanations were offered. Strict adherence to planned within-farm and community-based biosecurity, and avoidance of identified risk factors is recommended to reduce infection. Training for small-scale and emerging farmers should involve multidimensional and multidisciplinary approaches to reduce human-related risky behaviours driving infection.  相似文献   
2.
We conducted a matched case-control study to evaluate risk factors for infection with highly pathogenic avian influenza (HPAI) H5N1 virus in poultry farms during the epidemic of 2006-2007 in Nigeria. Epidemiologic data were collected through the use of a questionnaire from 32 case farms and 83 control farms. The frequency of investigated exposure factors was compared between case and control farms by using conditional logistic regression analysis. In the multivariable analysis, the variables for (i) receiving visitors on farm premises (odds ratio [OR]=8.32; 95% confidence interval [CI]=1.87, 36.97; P<0.01), (ii) purchased live poultry/products (OR=11.91; 95% CI=3.11-45.59; P<0.01), and (iii) farm workers live outside the premises (OR=8.98; 95% CI=1.97, 40.77; P<0.01) were identified as risk factors for HPAI in poultry farms. Improving farm hygiene and biosecurity should help reduce the risk for influenza (H5N1) infection in poultry farms in Nigeria.  相似文献   
3.
Avian influenza virus (H5N1) is a rapidly disseminating infection that affects poultry and, potentially, humans. Because the avian virus has already adapted to several mammalian species, decreasing the rate of avian–mammalian contacts is critical to diminish the chances of a total adaptation of H5N1 to humans. To prevent the pandemic such adaptation could facilitate, a biology‐specific disease surveillance model is needed, which should also consider geographical and socio‐cultural factors. Here, we conceptualized a surveillance model meant to capture H5N1‐related biological and cultural aspects, which included food processing, trade and cooking‐related practices, as well as incentives (or disincentives) for desirable behaviours. This proof of concept was tested with data collected from 378 Egyptian and Nigerian sites (local [backyard] producers/live bird markets/village abattoirs/commercial abattoirs and veterinary agencies). Findings revealed numerous opportunities for pathogens to disseminate, as well as lack of incentives to adopt preventive measures, and factors that promoted epidemic dissemination. Supporting such observations, the estimated risk for H5N1‐related human mortality was higher than previously reported. The need for multidimensional disease surveillance models, which may detect risks at higher levels than models that only measure one factor or outcome, was supported. To develop efficient surveillance systems, interactions should be captured, which include but exceed biological factors. This low‐cost and easily implementable model, if conducted over time, may identify focal instances where tailored policies may diminish both endemicity and the total adaptation of H5N1 to the human species.  相似文献   
4.
A case of a rapidly fatal disease in polo horses caused by African horsesickness (AHS) virus serotype 2 is described. The pattern of polo tournaments, environmental/management conditions (moist and warm), as well as probable importation strategies with no regard for import control and quarantine, favored introduction and spread of the virus. The outbreak, which involved a large number of horses, was characterized by severe respiratory distress, fever, supraorbital edema, and death. This is the first time a widespread epidemic of AHS has been reported in Nigeria and this is the first report of AHSV serotype 2 in the northern hemisphere. In addition, we amplified the complete genome of the virus using RNA extracted from clotted blood. This report indicates that AHS is expanding its geographical territory northwards and assuming a new microbial ecology.  相似文献   
5.
The main objective of this research was to construct accurate near-infrared reflectance (NIR) models of wood chemistry. Wet chemistry procedures and high-performance liquid chromatography methods were employed to analyze the chemical composition of southern pine. The NIR spectra were collected from 21 wood samples, which were milled down to different particle size classes. NIR calibration and prediction models were established using two modeling methods with different pretreatments. Furthermore, the spectrum range used in the NIR models was refined to achieve higher prediction accuracy. Results showed that NIR model precision could be improved considerably by decreasing the particle size to a very fine powder coupled with a targeted spectrum range. Superior prediction models for lignin and holocellulose content were constructed, while models for extractives and cellulose contents were also strong.  相似文献   
6.
Availability of gram quantities of purified soybean lectin (SBL) to scientists will foster discovery of novel biomedical applications of the lectin and provide the opportunity to investigate the antinutritional effects of SBL in soybean-consuming food animals and poultry. Therefore, a semi-pilot-scale procedure for isolating and purifying SBL was designed. Defatted soyflour was extracted overnight with 0.9% NaCl at 4 degrees C. The extract obtained was filtered (0.45 microm membrane) and subjected to affinity chromatography using a column containing N-acetyl-D-galactosamine resin that is specific for SBL. Bound SBL was eluted off the column with 0.14 M galactose solution. The eluent was ultrafiltered (30 kDa), and the resulting solution (SBL and water) was freeze-dried. Electrophoretic analysis and hemagglutination assay revealed that the freeze-dried SBL was similar to Sigma-grade SBL in purity and activity (35 and 33 HU/mg protein, respectively). The procedure yielded 141 mg of SBL/100 g of soyflour.  相似文献   
7.

Cattle production is the major livestock production activity and the mainstay of Namibia’s economy. Sustained beef exports are contingent on a sound sanitary environment where diseases such as brucellosis are under control. In this retrospective study, 49,718 bovine brucellosis testing results from 2004 to 2018 were analyzed to determine the proportion of sero-positive cattle and herds, and the spatial distribution of positive reactors from commercial and communal areas. In total, 244 positive reactors were identified based on the Rose Bengal Test (RBT) and the Complement Fixation Test (CFT) in series, giving an overall proportion of infected animals of 0.49% (244/49,718; 95% CI, 0.43–0.56%) and an overall proportion of infected herds of 9.26% (78/842; 95% CI, 7.49–11.41%). There was a higher proportion of sero-positive communal herds (33.09%) and cattle (10.27%) than commercial herds (4.67%) and cattle (0.24%; p < 0.05). Annually, the proportion of positive reactors was 0–1.37% in the commercial area and 0–52.38% in the communal areas, with a clear decline in positive reactors in the communal areas. Within the commercial sector, the proportion of positive reactor dairy, beef, and export cattle was 0.19% (51/27,067; 95% CI, 0.14–0.25%), 0.30% (48/16,098; 95% CI, 0.22–0.40%), and 0.33% (16/4811; 95% CI, 0.20–0.54%), respectively. Abortions were found to be the major reason for Brucella testing in the communal areas. About 12.65% (96/759) of abortion-linked sera tested positive in the communal areas, but none were positive in beef or dairy cattle. Widespread vaccination of cattle and robust planned surveillance is recommended to reduce the incidence of the disease, its associated production losses and public health risk.

  相似文献   
8.
In January 2006, an outbreak of a highly pathogenic avian influenza (HPAI) was recorded in Nigeria for the first time. This present work describes an estimation of possible costs associated with a vaccination-based control policy added to other measures to restrict HPAI H5N1 virus infections. The evaluations used epidemiological and production data, including budgets necessary for the vaccine acquisition, distribution and administration in arriving at the final costs. Using decision tree and cost benefit analysis the economical benefits for Nigeria and countries with similar veterinary infrastructures, biosecurity and farming systems are calculated. The result indicated that a halting in the continued spread of the virus through effective control measure will be 52 times better than taking no action. This should help policy makers in deciding in favour of vaccination combined with other tools as an effective means of controlling avian influenza H5N1. * Control of HPAI H5N1 will best be understood by policy makers in financial terms. * Effective control through vaccination of poultry is much cheaper and reduces the chances of human zoonoses. * Poultry vaccination combined with other control measures will be the most effective means of control in most developing economies.  相似文献   
9.
The control of Newcastle disease (ND) in South Africa has proved difficult since 2002 following the introduction of lineage 5d/VIId Newcastle disease virus (NDV) strain ("goose paramyxovirus" - GPMV) to which commercially available ND vaccines appeared less effective. Most of the ND infections, even in fully vaccinated hens were characterized consistently by a drop in egg production. In this study, commercial and SPF hens-in-lay were vaccinated with La Sota vaccine and challenged with a GPMV isolate. Immunohistochemical labeling was used to determine the distribution of viral antigen in the oviduct of the hens. Following reports that cloacal vaccination offered better protection against egg production losses than the oro-nasal route, the efficacy of cloacal and ocular routes of vaccination against challenge were compared. Results showed that La Sota vaccine offered birds 100% protection against the virulent ND (GPMV) virus challenge from clinical disease and death, but not against infection and replication of the GPMV, as birds showed varying degrees of macropathology. Histopathology of the oviduct of infected birds revealed multifocal lymphocytic inflammation in the interstitium as well as mild glandular ectasia and mild edema. Finely granular NDV-specific immunolabeling was demonstrated in the cytoplasm of epithelial cells and mononuclear (lymphohistiocytic) cells in the interstitium of the oviduct. Both vaccine and virulent GPMV showed greatest tropism for the uterus (versus the magnum and isthmus). There was no clear difference in the protection of the oviduct and in the distribution of oviductal GPMV antigens between the two routes of vaccination.  相似文献   
10.
South African pig sector is a contributor to the agricultural industry. A study was conducted to identify the production constraints and compare the management practices in smallholder pig farms in Mpumalanga, South Africa. A total of 220 selected smallholder pig farmers were interviewed. Smallholder pig farming was predominated by male (64 %), age above 50 years (54 %), black Africans (98.6 %), and three quarters of the smallholder farmers were poor to just below average. Majority (80 %) have no pig husbandry training, while only 33 % received assistance from government’s Agricultural Department. In terms of stock, mixed breeds (89 %) from exotic pigs were mostly kept and majority (87 %) of the farmers kept ≤10 sows in their herds. Many farmers (75 %) engaged in risky behavior of buying auctioned-sourced boars, free-range boars, and untested boars from neighbors and relatives. Few (17 %) farmers practiced vaccination and only 10 % kept farm records. Majority of the responses on pre-weaning mortality (50 %) and post-weaning mortality (90 %) were within acceptable range of 1–10 and 1–5 % mortality rates, respectively. The lead causes of mortality were weak piglets and crushing (46 %), diarrhea (27 %), poor management knowledge (19 %), and malnutrition (16 %). Agricultural training and government incentives will facilitate improved productivity in smallholder pig farming.  相似文献   
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