EpiX Analytics LLC

Boulder City, CO, United States

EpiX Analytics LLC

Boulder City, CO, United States
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Weber M.F.,GD Animal Health Service | Groenendaal H.,EpiX Analytics LLC
Veterinary Microbiology | Year: 2012

In many epidemiological models for paratuberculosis, it is assumed that infected young stock (<2 years of age) do not shed Mycobacterium avium subsp. paratuberculosis (MAP) before adulthood. If this assumption were true, the effective separation of young stock from adult cattle (≥2 years) would largely prevent postnatal infections, provided that uninfected adult cattle are highly resistant to infection. However, this assumption is in contrast with observed faecal shedding of MAP in young stock. Consequently, this assumption may have resulted in an underestimation of the effects of MAP transmission in herds participating in certification-, surveillance-, and control programmes for paratuberculosis. Therefore, the aim of the present study was to evaluate the long-term effects of transmission of MAP amongst young stock on key output parameters of certification-, surveillance-, and control programmes for paratuberculosis in simulated closed dairy herds. Closed Dutch dairy herds participating in a paratuberculosis programme were simulated with a stochastic model, JohneSSim. Various test schemes, preventive management measures, distributions of age at onset of faecal shedding and rates of effective contacts between young stock were simulated. The results indicate that transmission of MAP amongst young stock has no relevant effects on the animal-level prevalence and milk quality of herds that are certified in a paratuberculosis programme. However, transmission of MAP amongst young stock increased the economic losses due to paratuberculosis and costs of participation in a programme. Moreover, it substantially decreased the beneficial effect of the separation of young stock from adult cattle on the probability of being certified. However, even in the presence of transmission of MAP amongst young stock, preventive management measures to separate young stock from adult cattle remain important. © 2011 Elsevier B.V.


Espejo L.A.,University of Minnesota | Zagmutt F.J.,EpiX Analytics LLC | Groenendaal H.,EpiX Analytics LLC | Munoz-Zanzi C.,University of Minnesota | Wells S.J.,University of Minnesota
Journal of Dairy Science | Year: 2015

The objective of this study was to evaluate the performance of bacterial culture of feces and serum ELISA to correctly identify cows with Mycobacterium avium ssp. paratuberculosis (MAP) at heavy, light, and non-fecal-shedding levels. A total of 29,785 parallel test results from bacterial culture of feces and serum ELISA were collected from 17 dairy herds in Minnesota, Pennsylvania, and Colorado. Samples were obtained from adult cows from dairy herds enrolled for up to 10 yr in the National Johne's Disease Demonstration Herd Project. A Bayesian latent class model was fitted to estimate the probabilities that bacterial culture of feces (using 72-h sedimentation or 30-min centrifugation methods) and serum ELISA results correctly identified cows as high positive, low positive, or negative given that cows were heavy, light, and non-shedders, respectively. The model assumed that no gold standard test was available and conditional independency existed between diagnostic tests. The estimated conditional probabilities that bacterial culture of feces correctly identified heavy shedders, light shedders, and non-shedders were 70.9, 32.0, and 98.5%, respectively. The same values for the serum ELISA were 60.6, 18.7, and 99.5%, respectively. Differences in diagnostic test performance were observed among states. These results improve the interpretation of results from bacterial culture of feces and serum ELISA for detection of MAP and MAP antibody (respectively), which can support on-farm infection control decisions and can be used to evaluate disease-testing strategies, taking into account the accuracy of these tests. © 2015 American Dairy Science Association.


PubMed | University of Minnesota and EpiX Analytics LLC
Type: Journal Article | Journal: Journal of dairy science | Year: 2015

The objective of this study was to evaluate the performance of bacterial culture of feces and serum ELISA to correctly identify cows with Mycobacterium avium ssp. paratuberculosis (MAP) at heavy, light, and non-fecal-shedding levels. A total of 29,785 parallel test results from bacterial culture of feces and serum ELISA were collected from 17 dairy herds in Minnesota, Pennsylvania, and Colorado. Samples were obtained from adult cows from dairy herds enrolled for up to 10 yr in the National Johnes Disease Demonstration Herd Project. A Bayesian latent class model was fitted to estimate the probabilities that bacterial culture of feces (using 72-h sedimentation or 30-min centrifugation methods) and serum ELISA results correctly identified cows as high positive, low positive, or negative given that cows were heavy, light, and non-shedders, respectively. The model assumed that no gold standard test was available and conditional independency existed between diagnostic tests. The estimated conditional probabilities that bacterial culture of feces correctly identified heavy shedders, light shedders, and non-shedders were 70.9, 32.0, and 98.5%, respectively. The same values for the serum ELISA were 60.6, 18.7, and 99.5%, respectively. Differences in diagnostic test performance were observed among states. These results improve the interpretation of results from bacterial culture of feces and serum ELISA for detection of MAP and MAP antibody (respectively), which can support on-farm infection control decisions and can be used to evaluate disease-testing strategies, taking into account the accuracy of these tests.


Kouame-Sina S.M.,Nanguy Abrogoua University | Makita K.,Kenya International Livestock Research Institute | Makita K.,Rakuno Gakuen University | Costard S.,Royal Veterinary College | And 5 more authors.
Food and Nutrition Bulletin | Year: 2012

Background. Animal-source foods are important causes of food-borne illness, and milk and dairy products can contain pathogenic microorganisms. Objective. We conducted a stochastic assessment of the risk of ingesting milk contaminated with specific microbial pathogens (Escherichia coli, Staphylococcus aureus, and Enterococcus spp.) in Abidjan, Côte d'Ivoire. Methods. We carried out structured interviews and focus group discussions with farmers (n = 15), vendors (n = 17), and consumers (n = 188) to characterize dairy production systems and milk consumption behavior. Microbiological sampling was conducted at different points between milking and sale. A risk model was developed, and the risk of consuming contaminated raw milk was estimated by Monte Carlo simulation. Results. The investigation into local raw milk consumption patterns showed that the proportion of raw milk consumption was 51.6% in people who consume milk. The probability of ingestion of marketed raw milk that failed to meet standards for this group of bacteria was 29.9% and about 652 consumers per day were estimated to ingest contaminated milk. Microbiological tests from the farm showed that 7.2% of samples taken from milkers' hands, 4.4% of water samples (water used to rinse milk containers or milking utensils (calabash, plastic bottle, filters, buckets), 4.4% of environmental samples (air pollution), 13.2% of samples from milking utensils, and 4.9% of samples from cows' udders were contaminated with one or more of these pathogens. About 624.6 L of marketed raw milk would need to be discarded per day if discarding milk was chosen as the option of risk reduction. The destruction of this milk would result in a potential loss of €623.9 per day for all producers. Conclusions. The risk of human illness from consumption of raw milk could be mitigated by raising awareness about heat treatment of milk and good hygiene practices in the dairy chain. © 2012, The United Nations University.


Espejo L.A.,EpiX Analytics LLC | Costard S.,EpiX Analytics LLC | Zagmutt F.J.,EpiX Analytics LLC
Epidemiology and Infection | Year: 2015

Expansion of sandflies and increasing pet travel have raised concerns about canine leishmaniasis (CanL) spread to new areas of Europe. This study aimed to estimate the probability of CanL introduction and persistence following movements of infected dogs. Stochastic modelling was used to estimate the probabilities of (1) CanL infection during travels or imports of infected dogs (Pinf and PinfCA, respectively), (2) CanL persistence in a dog network with sandflies after introduction of an infected dog (Pper), and (3) persistence in a CanL-free region (Pper region) for N dogs moving between endemic and free regions. Different mitigation measures (MMs) were assessed. Pinf [7·8%, 95% predictive interval (PI) 2·6-16·4] and Pper (72·0%, 95% PI 67·8-76·0) were reduced by use of repellent, vaccine, prophylactic medication, and insecticide, in decreasing order of effectiveness. Testing and exclusion of positive dogs was most effective in reducing Pper region for a small N. The spread of CanL to CanL-free areas with sandflies is thus likely, but can be reduced by MMs. Copyright © Cambridge University Press 2014.


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EpiX Analytics LLC | Date: 2013-05-21

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PubMed | EpiX Analytics LLC
Type: Journal Article | Journal: Epidemiology and infection | Year: 2015

Expansion of sandflies and increasing pet travel have raised concerns about canine leishmaniasis (CanL) spread to new areas of Europe. This study aimed to estimate the probability of CanL introduction and persistence following movements of infected dogs. Stochastic modelling was used to estimate the probabilities of (1) CanL infection during travels or imports of infected dogs (P inf and P infCA, respectively), (2) CanL persistence in a dog network with sandflies after introduction of an infected dog (P per), and (3) persistence in a CanL-free region (P per region) for N dogs moving between endemic and free regions. Different mitigation measures (MMs) were assessed. P inf [7.8%, 95% predictive interval (PI) 2.6-16.4] and P per (72.0%, 95% PI 67.8-76.0) were reduced by use of repellent, vaccine, prophylactic medication, and insecticide, in decreasing order of effectiveness. Testing and exclusion of positive dogs was most effective in reducing P per region for a small N. The spread of CanL to CanL-free areas with sandflies is thus likely, but can be reduced by MMs.

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