Methods to investigate spatial and temporal clustering in veterinary epidemiology

Carpenter, Tim E.

doi:10.1016/s0167-5877(00)00199-9

Cited by 86 publications

(64 citation statements)

References 65 publications

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“…Clusters of diseases can occur within a group, pasture, herd, or region. Not accounting for clustering when it occurs may lead to false conclusions (Carpenter, 2001). The REML analyses partially account for clustering by considering contemporary groups, which averages out the effects of years and pastures from the sire effects.…”

Section: Resultsmentioning

confidence: 99%

Genetic and environmental factors associated with incidence of infectious bovine keratoconjunctivitis in preweaned beef calves1

Snowder

Vleck

Cundiff

et al. 2005

Journal of Animal Science

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Infectious bovine keratoconjunctivitis (IBK) is one of the most economically important diseases in preweaned calves. This study examined the health records of 45,497 calves over a 20-yr period to determine environmental and genetic factors influencing the incidence of IBK. Three data sets were analyzed with an animal model. The first data set (n = 41,986) evaluated environmental factors and genetic differences among nine purebred (Angus, Braunvieh, Charolais, Gelbvieh, Hereford, Limousin, Pinzgauer, Red Poll, and Simmental) and three composite breeds (MARC I, MARC II, and MARC III). Weaning weights of calves diagnosed with IBK were 8.9 kg lighter (P < 0.05) than weights of healthy calves. Incidence of IBK was related to age of the calf and the seasonal life cycle of the face fly (Musca autumnalis). Incidence of IBK increased in the spring (June), peaked during the summer months (July to September), and then decreased in the fall. Herefords were the most susceptible breed (P < 0.05) compared with all other purebreds and composites. Estimates of direct heritability for the incidence of IBK were generally low and ranged from 0.00 to 0.28 by breed. The maternal permanent environmental and

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Section: Resultsmentioning

confidence: 99%

Genetic and environmental factors associated with incidence of infectious bovine keratoconjunctivitis in preweaned beef calves1

Snowder

Vleck

Cundiff

et al. 2005

Journal of Animal Science

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“…Geographic and temporal clustering of overall carcass retrieval and temporal clustering of each primary cause of death were evaluated by the scan test (Carpenter, 2001). This test evaluates whether carcass retrieval was uniform using the binomial distribution to estimate the probability of the maximum observed number of cases within sequential distances of 5 km, 10 km, 15 km, and 20 km for geographic clustering and within 1, 2, 3 and 4 mo for temporal clustering.…”

Section: Statistical Analysesmentioning

confidence: 99%

Patterns of Mortality in Southern Sea Otters (Enhydra Lutris Nereis) From 1998–2001

Kreuder

Miller

Jessup

et al. 2003

Journal of Wildlife Diseases

234

178

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Detailed postmortem examination of southern sea otters (Enhydra lutris nereis) found along the California (USA) coast has provided an exceptional opportunity to understand factors influencing survival in this threatened marine mammal species. In order to evaluate recent trends in causes of mortality, the demographic and geographic distribution of causes of death in freshly deceased beachcast sea otters necropsied from 1998-2001 were evaluated. Protozoal encephalitis, acanthocephalan-related disease, shark attack, and cardiac disease were identified as common causes of death in sea otters examined. While infection with acanthocephalan parasites was more likely to cause death in juvenile otters, Toxoplasma gondii encephalitis, shark attack, and cardiac disease were more common in prime-aged adult otters. Cardiac disease is a newly recognized cause of mortality in sea otters and T. gondii encephalitis was significantly associated with this condition. Otters with fatal shark bites were over three times more likely to have preexisting T. gondii encephalitis suggesting that shark attack, which is a long-recognized source of mortality in otters, may be coupled with a recently recognized disease in otters. Spatial clusters of cause-specific mortality were detected for T. gondii encephalitis (in Estero Bay), acanthocephalan peritonitis (in southern Monterey Bay), and shark attack (from Santa Cruz to Point Añ o Nuevo). Diseases caused by parasites, bacteria, or fungi and diseases without a specified etiology were the primary cause of death in 63.8% of otters examined. Parasitic disease alone caused death in 38.1% of otters examined. This pattern of mortality, observed predominantly in juvenile and prime-aged adult southern sea otters, has negative implications for the overall health and recovery of this population.

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“…It is different from a timespace clustering because it detects a temporal clustering of events in specific locations, simultaneously, without regards to the proximity of locations to one another [8]. It was used to check if the time distribution of the trimester of birth varied between regions.…”

Section: Analysis Of Clusters In Space and Timementioning

confidence: 99%

A spatio-temporal analysis of BSE cases born before and after the reinforced feed ban in France

Ducrot¹,

Abrial²,

Calavas³

et al. 2005

Vet. Res.

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-A spatio-temporal analysis was carried out to see how the risk distribution of bovine spongiform encephalopathy (BSE) in France changed depending on the period of birth. The data concerned the 539 BSE cases born in France after the ban (BAB) of meat and bone meal (MBM) in 1990 and detected between July 1, 2001 and December 31, 2003, when the surveillance of BSE was comprehensive. Seventy-two of these cases were born after the reinforced (second) ban (BASB) in 1996, which involved the removal of BSE-risk materials and cadavers from the processing of MBM. The Ederer-Myers-Mantel (EMM) time and space cluster test was applied, after classifying the cases by trimester and region of birth, BAB or BASB status, and dairy or beef status. Then disease mapping was performed for four successive birth periods, three for the BAB cases (January 1991 through June 1994, July 1994 through June 1995, July 1995 through June 1996), and one for the BASB (July 1996 through October 1998). It was elaborated with the Bayesian graphical modelling methods and based on a Poisson distribution with spatial smoothing. The parameters were estimated by a Markov Chain Monte Carlo (MCMC) simulation method. The main finding was that the areas with the highest risk of BSE changed largely from one birth period to another; from the west, it reached the east of France for birth cohort 1994-1995 and the southwest for birth cohort 1995-1996. The EMM test identified a peak risk in this region both for dairy and beef cattle in the fall 1995. The spatial distribution of the risk for the BASB cases matched the spatial pattern of risk for the preceding BAB birth cohort quite well; this was in favour of a common origin of the infection of the BAB and BASB cases, despite the complementary control measures.BSE / bovine / spatio-temporal / disease mapping / Ederer-Myers-Mantel

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Methods to investigate spatial and temporal clustering in veterinary epidemiology

Cited by 86 publications

References 65 publications

Genetic and environmental factors associated with incidence of infectious bovine keratoconjunctivitis in preweaned beef calves1

Genetic and environmental factors associated with incidence of infectious bovine keratoconjunctivitis in preweaned beef calves1

Patterns of Mortality in Southern Sea Otters (Enhydra Lutris Nereis) From 1998–2001

A spatio-temporal analysis of BSE cases born before and after the reinforced feed ban in France

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