Scott J Wells

Prof. Scott J Wells


Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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13 June 2019 in BMC Veterinary Research
Verified
Journal Article
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RWRichard J. Whittington
Richard J. Whittington
KDKarsten Ulrich Donat
Karsten Ulrich Donat
MWMaarten F. Weber
Maarten F. Weber
DKDavid Kelton
David Kelton
SNSøren Nielsen
Søren Nielsen
JWJacobus H. De Waard
Jacobus H. De Waard
Paratuberculosis, a chronic disease affecting ruminant livestock, is caused by Mycobacterium avium subsp. paratuberculosis (MAP). It has direct and indirect economic costs, impacts animal welfare and arouses public health concerns. In a survey of 48 countries we found paratuberculosis to be very common in livestock. In about half the countries more than 20% of herds and flocks were infected with MAP. Most countries had large ruminant populations (millions), several types of farmed ruminants, multiple husbandry systems and tens of thousands of individual farms, creating challenges for disease control. In addition, numerous species of free-living wildlife were infected. Paratuberculosis was notifiable in most countries, but formal control programs were present in only 22 countries. Generally, these were the more highly developed countries with advanced veterinary services. Of the countries without a formal control program for paratuberculosis, 76% were in South and Central America, Asia and Africa while 20% were in Europe. Control programs were justified most commonly on animal health grounds, but protecting market access and public health were other factors. Prevalence reduction was the major objective in most countries, but Norway and Sweden aimed to eradicate the disease, so surveillance and response were their major objectives. Government funding was involved in about two thirds of countries, but operations tended to be funded by farmers and their organizations and not by government alone. The majority of countries (60%) had voluntary control programs. Generally, programs were supported by incentives for joining, financial compensation and/or penalties for non-participation. Performance indicators, structure, leadership, practices and tools used in control programs are also presented. Securing funding for long-term control activities was a widespread problem. Control programs were reported to be successful in 16 (73%) of the 22 countries. Recommendations are made for future control programs, including a primary goal of establishing an international code for paratuberculosis, leading to universal acknowledgment of the principles and methods of control in relation to endemic and transboundary disease. An holistic approach across all ruminant livestock industries and long-term commitment is required for control of paratuberculosis.

1 January 2016 in Preventive Veterinary Medicine
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Journal Article
Closed access
Kimberly VanderWaalKimberly VanderWaal
Kimberly VanderWaal
Catalina Picasso RissoCatalina Picasso Risso
Catalina Picasso Risso
EEEva Enns
Eva Enns
MCMeggan E Craft
Meggan E Craft
JAJulio Alvarez
Julio Alvarez
SWScott J Wells
Scott J Wells

1 October 2006 in Clinical and Vaccine Immunology
Verified
Journal Article
Closed access
SWScott J Wells
Scott J Wells
MCMichael T. Collins
Michael T. Collins
KFKay S. Faaberg
Kay S. Faaberg
CWCarrie Wees
Carrie Wees
STSaraya Tavornpanich
Saraya Tavornpanich
RWRobert H. Whitlock
Robert H. Whitlock
A high-throughput TaqMan PCR assay for detection of bovine paratuberculosis was evaluated by using fecal samples from 1,808 dairy cattle in seven naturally infected herds and 347 dairy cattle in seven herds considered free of paratuberculosis. Fecal, blood, and milk samples were submitted to laboratories where the PCR-based assay, three different fecal culture procedures forMycobacterium aviumsubsp.paratuberculosis(centrifugation, sedimentation, and the BACTEC filter concentration method), two serologic enzyme-linked immunosorbent assays (ELISAs), and one milk ELISA were performed. Results from testing of dairy cattle in herds free ofM. aviumsubsp.paratuberculosisshowed that the PCR assay's specificity was 99.7%. Twenty-three percent of the dairy cows that were fecal culture positive by at least one of the three methods were positive by the PCR assay. By Bayesian non-“gold standard” analysis methods, the TaqMan PCR assay had a higher specificity than the serum ELISAs (99.3%; 95% confidence interval [CI] = 98.6 to 99.7%) and a test sensitivity similar to that of the serum ELISAs (29%; 95% CI = 24 to 35%). By classical methods, the estimated relative sensitivity of the fecal PCR assay was 4% for light and moderate fecal shedders (compared to 12 to 13% for the ELISAs) and 76% for heavy fecal shedders (compared to 67% for the milk ELISA). The PCR assay has higher sensitivity for detection of heavy fecal shedders than the evaluated milk ELISA but lower sensitivity than a serum or milk ELISA for detection of light and moderate fecal shedders. This assay can be used as a quick test for detection of cattle with heavy fecal shedding, those cattle with the highest risk of transmitting infection to susceptible cattle.

12 October 2010 in BMC Genomics
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Journal Article
Open access
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HJHarish K Janagama
Harish K Janagama
ELElise A Lamont
Elise A Lamont
SGSajan Daniel George
Sajan Daniel George
JBJohn Bannantine
John Bannantine
WXWayne W Xu
Wayne W Xu
Srinand SreevatsanSrinand Sreevatsan
Srinand Sreevatsan
Background: Mycobacterium avium subsp. paratuberculosis (MAP) persistently infects intestines and mesenteric lymph nodes leading to a prolonged subclinical disease. The MAP genome sequence was published in 2005, yet its transcriptional organization in natural infection is unknown. While prior research analyzed regulated gene sets utilizing defined, in vitro stress related or advanced surgical methods with various animal species, we investigated the intracellular lifestyle of MAP in the intestines and lymph nodes to understand the MAP pathways that function to govern this persistence. Results: Our transcriptional analysis shows that 21%, 8% and 3% of the entire MAP genome was represented either inside tissues, macrophages or both, respectively. Transcripts belonging to latency and cell envelope biogenesis were upregulated in the intestinal tissues whereas those belonging to intracellular trafficking and secretion were upregulated inside the macrophages. Transcriptomes of natural infection and in vitro macrophage infection shared genes involved in transcription and inorganic ion transport and metabolism. MAP specific genes within large sequence polymorphisms of ancestral M. avium complex were downregulated exclusively in natural infection. Conclusions: We have unveiled common and unique MAP pathways associated with persistence, cell wall biogenesis and virulence in naturally infected cow intestines, lymph nodes and in vitro infected macrophages. This dichotomy also suggests that in vitro macrophage models may be insufficient in providing accurate information on the events that transpire during natural infection. This is the first report to examine the primary transcriptome of MAP at the local infection site (i.e. intestinal tissue). Regulatory pathways that govern the lifecycle of MAP appear to be specified by tissue and cell type. While tissues show a "shut-down" of major MAP metabolic genes, infected macrophages upregulate several MAP specific genes along with a putative pathogenicity island responsible for iron acquisition. Many of these regulatory pathways rely on the advanced interplay of host and pathogen and in order to decipher their message, an interactome must be established using a systems biology approach. Identified MAP pathways place current research into direct alignment in meeting the future challenge of creating a MAP-host interactome.

27 February 2017 in Avian Diseases
Verified
Journal Article
Closed access
SWScott J Wells
Scott J Wells
MKM. M. Kromm
M. M. Kromm
EVE. T. VanBeusekom
E. T. VanBeusekom
ESE. J. Sorley
E. J. Sorley
MSM. E. Sundaram
M. E. Sundaram
JBJ. Bender
J. Bender
SUMMARY In 2015, an outbreak of H5N2 highly pathogenic avian influenza (HPAI) occurred in the United States, severely impacting the turkey industry in the upper midwestern United States. Industry, government, and academic partners worked together to conduct a case-control investigation of the outbreak on turkey farms in the Upper Midwest. Case farms were confirmed to have HPAI-infected flocks, and control farms were farms with noninfected turkey flocks at a similar stage of production. Both case and control farms were affiliated with a large integrated turkey company. A questionnaire administered to farm managers and supervisors assessed farm biosecurity, litter handling, dead bird disposal, farm visitor and worker practices, and presence of wild birds on operations during the 2 wk prior to HPAI confirmation on case premises and the corresponding time frame for control premises. Sixty-three farms, including 37 case farms and 26 control farms were included in the analysis. We identified several factors sig... RESUMEN Investigación epidemiológica de la influenza aviar altamente patógena H5N2 en granjas de pavos en la parte norte del medio oeste de los Estados Unidos en el año 2015. En el año 2015, se produjo un brote de influenza aviar altamente patógena H5N2 en los Estados Unidos, lo que afectó severamente a la industria del pavo en el medio oeste de este país. La industria, el gobierno y el sector académico trabajaron juntos para llevar a cabo un estudio de casos y controles con relación al brote en granjas de pavos en la parte norte del medio oeste de los Estados Unidos. Se confirmó que las granjas de los casos tenían parvadas infectadas por la influenza aviar y las granjas de control eran granjas con parvadas de pavos no infectadas en una etapa similar de producción. Tanto las granjas de casos como las controles estaban afiliadas a una gran empresa integrada de pavos. Se administró un cuestionario a los gerentes y supervisores de la granja que evaluó la bioseguridad de la granja, el manejo de la cama, la el...

25 January 2018 in BMC Veterinary Research
Verified
Journal Article
Open access
PDF file
GMGustavo Machado
Gustavo Machado
KKKaushi S.T. Kanankege
Kaushi S.T. Kanankege
VSVal Schumann
Val Schumann
SWScott J Wells
Scott J Wells
APAndres Perez
Andres Perez
JAJulio Alvarez
Julio Alvarez
Mycobacterium avium subsp. paratuberculosis (MAP) is a widespread chronic disease of ruminants that causes severe economic losses to the dairy cattle industry worldwide. The objective of this study was to evaluate the association between individual cow MAP-ELISA and relevant milk production predictors in dairy cattle using data routinely collected as part of quality and disease control programs in the Midwest region of the U.S. Milk ELISA results of 45,652 animals from 691 herds from November 2014 to August 2016 were analyzed. The association between epidemiological and production factors and ELISA results for MAP in milk was quantified using four individual-level mixed multivariable logistic regression models that accounted for clustering of animals at the farm level. The four fitted models were one global model for all the animals assessed here, irrespective of age, and one for each of the categories of < 4 year-old, 4–8 year-old, and > 8 year-old cattle, respectively. A small proportion (4.9%; n = 2222) of the 45,652 tested samples were MAP-seropositive. Increasing age of the animals and higher somatic cell count (SCC) were both associated with increased odds for MAP positive test result in the model that included all animals, while milk production, milk protein and days in milk were negatively associated with MAP milk ELISA. Somatic cell count was positively associated with an increased risk in the models fitted for < 4 year-old and 4–8 year-old cattle. Variables describing higher milk production, milk protein content and days in milk were associated with significantly lower risk in the models for 4–8 year-old cattle and for all cattle. Our results suggest that testing cows with high SCC (> 26 × 1000/ml), low milk production and within the first 60 days of lactation may maximize the odds of detecting seropositive animals. These results could be useful in helping to design better surveillance strategies based in testing of milk.