Prediction of province-level outbreaks of foot-and-mouth disease in Iran using a zero-inflated negative binomial model.

To identify events that could predict province-level frequency of foot-and-mouth disease (FMD) outbreaks in Iran, 5707 outbreaks reported from April 1995 to March 2002 were studied. A zero-inflated negative binomial model was used to estimate the probability of a 'no-outbreak' status and the number of outbreaks in a province, using the number of previous occurrences of FMD for the same or adjacent provinces and season as covariates. For each province, the probability of observing no outbreak was negatively associated with the number of outbreaks in the same province in the previous month (odds ratio [OR]=0.

Factors associated with spatial clustering of foot-and-mouth disease in Nepal.

The purpose of this study was to quantify associations between hypothesized epidemiological factors and the spatial distribution of foot-and-mouth disease (FMD) in Nepal. Spatial clustering of reports of at least one FMD case by Village Development Committee (VDC) in 2004 was examined by use of the spatial scan statistic. A Bayesian Poisson multivariate regression model was used to quantify the association between the number of reports and 25 factors hypothesized to be associated with FMD risk.

Visualization and analysis of the Danish 2006 highly pathogenic avian influenza virus H5N1 wild bird surveillance data by a prototype avian influenza BioPortal.

Infection with highly pathogenic avian influenza virus H5N1 occurred for the first time in Denmark in 2006 during the last part of the European epidemic that mainly affected migrating wild birds. The total number of Danish wild bird cases was 45, of which only one was found through active surveillance using fecal sampling from resting areas for migrating species, whereas passive surveillance of dead wild birds provided 44 cases. One backyard, mixed poultry flock also became infected late in the epidemic.

Automatic online news monitoring and classification for syndromic surveillance.

Syndromic surveillance can play an important role in protecting the public's health against infectious diseases. Infectious disease outbreaks can have a devastating effect on society as well as the economy, and global awareness is therefore critical to protecting against major outbreaks. By monitoring online news sources and developing an accurate news classification system for syndromic surveillance, public health personnel can be apprised of outbreaks and potential outbreak situations.

A web-based system for near real-time surveillance and space-time cluster analysis of foot-and-mouth disease and other animal diseases.

Considerable attention has been given lately to the need for global systems for animal disease surveillance that support real-time assessment of changing temporal-spatial risks. Until recently, however, prospects for development of such systems have been limited by the lack of informatics tools and an overarching collaboration framework to enable real-time data capturing, sharing, analysis, and related decision-making. In this paper, we present some of the tools of the FMD BioPortal System (www.

Fluorescence-based multiplex real-time RT-PCR arrays for the detection and serotype determination of foot-and-mouth disease virus.

This study reports the development of distinct fluorescence-based multiplex rRT-PCR arrays, which are comprised of unique primer pairs that are statistically modeled from publicly available sequences, for overall foot-and-mouth disease virus and serotype-specific detection. Performance of the multiplex pan FMDV (MpFMDV) array was compared to the 5' UTR and two 3D(pol) assays, following tests on the Miniopticon (BioRad) and 7900HT SDS (ABI) platforms. The MpFMDV array and a recently developed alternative 3D(pol) assay correctly identified all 31 isolates that represented all seven serotypes, including 10 isolates reported previously to be undetectable by both OIE recommended assays (5' UTR and 3D(pol) assay).

Variation in the VP1 gene of foot-and-mouth disease virus serotype A associated with epidemiological characteristics of outbreaks in the 2001 epizootic in Argentina.

A mixed binomial Bayesian regression model was used to quantify the relation between nucleotide differences in the VP1 gene of Foot-and-mouth disease virus (FMDV) serotype A, and epidemiologic characteristics of the outbreaks from which the viruses were obtained between January and December 2001 in Argentina. An increase in the probability of different nucleotides between isolates was associated with a longer time between isolation dates, a greater distance between isolation locations, an increase in the difference between attack rates, and an increase in the difference in outbreak durations. The farther apart the outbreak herds were in the southerly and easterly directions, the greater the difference in nucleotide changes.

Prediction model for sequence variation in the glycoprotein gene of infectious hematopoietic necrosis virus in California, U.S.A.

The influence of spatio-temporal factors on genetic variation of infectious hematopoietic necrosis virus (IHNV) is an active area of research. Using host-isolate pairs collected from 1966 to 2004 for 237 IHNV isolates from California and southern Oregon, we examined genetic variation of the mid-G gene of IHNV that could be quantified across times and geographic locations. Information hypothesized to influence genetic variation was environmental and/or fish host demographic factors, viz.

Temporal-spatial epidemiology of foot-and-mouth disease outbreaks in Mongolia, 2000 - 2002.

Prior to 2000, foot-and-mouth disease (FMD) had not been observed in Mongolia since 1973; however, between April 2000 and July 2002, Mongolia reported 44 FMD outbreaks that affected cattle, sheep, goats, and camels. The objectives of this study were to describe the distributions of the 44 reported FMD outbreaks in Mongolia and to assess their spatial clustering and directions of movement. Official reports were collected to obtain the number and species of animals both affected and at risk, and the date and geographical coordinates of each outbreak.

Results of a survey of owners of miniature swine to characterize husbandry practices affecting risks of foreign animal disease.

Objective: To characterize husbandry practices that could affect the risks of foreign animal disease in miniature swine.

Design: Survey study.

Study Population: 106 owners of miniature swine.

Modeled detection time for surveillance for foot-and-mouth disease virus in bulk tank milk.

Objective: To estimate when foot-and-mouth disease virus (FMDV) would first be detected in bulk tank milk of dairies after exposure to FMDV.

Sample Population: Hypothetical dairy herds milking 100, 500, or 1,000 cows.

Procedures: For each day after herd exposure to FMDV, infection, milk yield, and virolactia were simulated for individual cows with low and high rates of intraherd transmission to estimate when a PCR assay would detect virus in bulk tank milk.

Spatial distribution of foot-and-mouth disease in Pakistan estimated using imperfect data.

We estimated the spatial distribution of foot-and-mouth disease (FMD) in Pakistan; we used a probability co-kriging model and the number of FMD outbreaks reported between 1996 and 2000 by Pakistan to the Office International des Epizooties. We used a k-Bessel model and small-ruminant and human densities as surrogate covariates for the population at risk and for livestock markets and movements, respectively. Compared to no or only one covariate, the co-kriging model with both densities provided the best fit to independently obtained data on the spatial distribution of virus isolations (P=0.

Factors affecting sensitivity and specificity of pooled-sample testing for diagnosis of low prevalence infections.

Testing of pooled samples has been proposed as a low-cost alternative for diagnostic screening and surveillance for infectious agents in situations where the prevalence of infection is low and most samples can be expected to test negative. The present study extends our previous work in pooled-sample testing (PST) to evaluate effects of the following factors on the overall PST sensitivity (SE(k)) and specificity (SP(k)): dilution (pool size), cross-contamination, and cross-reaction. A probabilistic model, in conjunction with Monte Carlo simulations, was used to calculate SE(k) and SP(k), as applied to detection of bovine viral diarrhea virus (BVDV) persistently infected (PI) animals using RT-PCR.

Diagnosis using predictive probabilities without cut-offs.

Standard diagnostic test procedures involve dichotomization of serologic test results. The critical value or cut-off is determined to optimize a trade off between sensitivity and specificity of the resulting test. When sampled units from a population are tested, they are allocated as either infected or not according to the test outcome.

Use of the scan statistic on disaggregated province-based data: foot-and-mouth disease in Iran.

The spatial scan statistic was applied to density-smoothed data that approximated the spatial distribution within the area and reduced the potential bias produced when location data have been aggregated for large areas. The method is illustrated, using data on the location of foot-and-mouth disease (FMD) outbreaks in Iran. Data examined were 4477 FMD outbreaks reported on a per province basis between June 1996 and September 2003.

Evaluation of Mycobacterium avium subsp paratuberculosis infection of dairy cows attributable to infection status of the dam.

Objective: To estimate the extent to which infection with Mycobacterium avium subsp paratuberculosis (MAP) of cows in a large dairy was attributable to the infection status of their dams.

Design: Retrospective longitudinal study.

Animals: 625 dam-daughter pairs of Holstein cows.

Mycoplasma otitis in California calves.

A retrospective study of Mycoplasma otitis in California calves submitted for necropsy between 1993 and 2002 was conducted to characterize the demographic features of the disease and the pathologic findings associated with infection. Sixty-one confirmed cases of Mycoplasma otitis were identified among 20,525 necropsied cattle. All affected animals were calves, ranging in age from 2 weeks to 4 months and with a median age of 1.

Influence of age and production type on liver copper concentrations in calves.

A retrospective study of necropsy reports was undertaken to assess the relation between liver copper concentration and age, sex, and production class for calves that did not have a history compatible with copper toxicosis or with copper deficiency. Results of a generalized least squares regression analysis of 601 records found that copper concentration was as much as 60 mg/kg wet weight higher for dairy calves than for beef calves (P < 0.00001, R2 = 0.

Influence of age, sex, and production class on liver zinc concentration in calves.

Determination of zinc concentrations in the liver of calves and young stock is commonly requested by practitioners and nutritionists to assess whether they receive an appropriate amount of zinc in their diet. However, interpretation of liver zinc concentrations is currently based on information reported for adult cattle for which the health status was unknown and irrespective of production class, sex, and age. A retrospective study of necropsy reports was undertaken to assess the relationships between liver zinc concentrations and age, sex, and production class for calves that did not have a history compatible with zinc toxicosis or zinc deficiency.

Effect of multiple sampling on diagnostic sensitivity.

Overall diagnostic sensitivity is the probability that a diagnostic procedure will detect an agent if the tested animal is indeed infected. The overall or effective sensitivity is a function of both the probability that the assay will detect the agent if it is present in the sample tested and the probability that the agent will be present in the sample tested if the animal is infected with the agent. Thus, even with a highly sensitive assay, the probability of detecting an infected animal may be low or nil if the sampling procedure failed to capture the agent in samples tested by the assay.

Effect of bovine viral diarrhea virus infection on fertility of dairy heifers.

A prospective field study in heifers from birth to first breeding was undertaken on two commercial dairies to assess the effect of bovine viral diarrhea virus (BVDV) congenital and post-natal infection (PNI) on fertility. A high BVDV Type 2 antibody titer (1:4096) at 10 months of age was associated with 32 more days to conceive, compared with a low titer (1:128). Conversely, infection with BVDV by 5-6 months of age and high BVDV Type 2 titers 1 month before conception or breeding was associated with improved fertility.

A simulation model of intraherd transmission of foot and mouth disease with reference to disease spread before and after clinical diagnosis.

Intraherd transmission of foot and mouth disease virus (FMDV) was examined using a simulation model for a hypothetical 1,000-cow dairy, assuming clinical diagnosis was made when at least 1% (10 cows) or 5% (50 cows) had clinical signs of FMD, I index case cow, and transition state distributions for the latent, subclinically infectious, and clinically infectious periods of FMD calculated from published data. Estimates assumed for the number of animal-to-animal contacts (k) adequate for transmission ranged from 0.6 to 9.

Conceptual foundations for infectious disease surveillance.

The purpose of this report is to offer concepts for consideration in developing infectious disease surveillance systems, defined here as active, formal, and systematic processes intentionally directed to rapidly seek out and identify infectious disease agents or disease. Performance of surveillance systems can be judged by their accuracy (sensitivity and specificity), precision (repeatability), timeliness, multiple utility, and value. Surveillance system operation and function necessary to achieve high performance are defined in part by characteristics of the specific infectious disease, including disease transition state dynamics, that define probabilities of being in the latent, infectious, or clinical phase of disease.

Changes in proportion of canine urinary calculi composed of calcium oxalate or struvite in specimens analyzed from 1981 through 2001.

The objective of this report was to characterize 20-year changes in proportion of calcium oxalate (CaOx) calculi and struvite calculi in dogs, and associations with breed, age, and sex. In this retrospective study, results of analysis of urinary calculi from dogs were reviewed for specimens received between July 1, 1981, and December 31, 2001. Breed, sex, age, year of submission of the specimen, and mineral type(s) were analyzed statistically.