The use of discriminant analysis in predicting the distribution of bluetongue virus in Queensland, Australia

Mp, Ward

doi:10.1007/bf01839261

Cited by 10 publications

(2 citation statements)

References 24 publications

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“…Similar stress effects could suppress populations of C. bolitinos in hotter environments. Modelling done on an allopatric, identical sister species C. brevitarsis in Australia found that mean maximum temperatures could predict BTV infection (and thus C. brevitarsis distribution) with an accuracy of ~75% [ 50 ]. Considering the notable similarity of C. bolitinos and C. brevitarsis in morphology, habitat and habit, it is possible that it could be similarly employed.…”

Section: Discussionmentioning

confidence: 99%

Thermal limits of two biting midges, Culicoides imicola Kieffer and C. bolitinos Meiswinkel (Diptera: Ceratopogonidae)

2014

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BackgroundCulicoides imicola Kieffer and Culicoides bolitinos Meiswinkel (Diptera: Ceratopogonidae) are both of veterinary importance, being vectors of Schmallenberg, bluetongue and African horse sickness (AHS) viruses. Within South Africa, these Culicoides species show a marked difference in their abundances according to altitude, with C. imicola highly abundant in lower altitudes, but being replaced as the dominant species by C. bolitinos in cooler, high-altitude regions.MethodsThe thermal physiology of field collected adults of each species was determined to evaluate whether it could account for differences in their distribution and abundance. Critical thermal maxima (CTmax) and minima (CTmin), as well as upper and lower lethal temperatures (ULT and LLT) were assessed after acclimation temperatures of 19ˌC, 24ˌC and 29ˌC. Critical thermal limits were determined using an ecologically relevant rate of temperature change of 0.06ˌC.min−1.ResultsSignificant differences in CTmin and CTmax were found between acclimation temperatures for C. imicola and C. bolitinos. In C. bolitinos, the LLT of individuals acclimated at 24ˌC was significantly improved (LLT50 = −6.01ˌC) compared with those acclimated at the other temperatures (LLT50 = −4ˌC). Acclimation had a weak (difference in LLT50 of only 1ˌC) but significant effect on the LLT of C. imicola. When CTmin, CTmax, LLT and ULT were superimposed on daily maximum and minimum temperature records from locations where each tested Culicoides species is dominant, it was found that temperatures frequently declined below the CTmin and LLT of C. imicola at the location where C. bolitinos was dominant.ConclusionsThe distribution and abundance of C. imicola is likely directly constrained by their relatively poor tolerance of lower temperatures. Results for C. bolitinos suggest that the adult phase is hardy, and it is hypothesised that the thermal biology of other life stages could determine their range.Electronic supplementary materialThe online version of this article (doi:10.1186/1756-3305-7-384) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Thermal limits of two biting midges, Culicoides imicola Kieffer and C. bolitinos Meiswinkel (Diptera: Ceratopogonidae)

2014

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“…The negative and positive results of iELISA test were classified as 0 and 1 respectively. Mean value of each climate parameter corresponding to the location of sample collection was analyzed using linear discriminant analysis (Ward 1994) to determine the parameter discriminating the negative and positive sample…”

Section: Linear Discriminant Analysismentioning

confidence: 99%

Seroprevalence of Trypanosoma evansi in cattle and analysis of associated climatic risk factors in Mizoram, India

et al. 2020

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Surra, a haemoprotozoan parasitic disease even in subclinical form poses a challenge in terms of diagnosis and management to animal health practitioners and policy makers as well; eventually imparting financial loss to the livestock holders. A systematic study was designed to assess the seroprevalence of surra in cattle and associated climatic risk factors, by collecting 480 serum samples across the eight districts of Mizoram during 2017-2019. The apparent and true seroprevalence detected by card agglutination test was 37.08% (CI at 95%: 32.88-41.49) and 36.59% (CI at 95%: 32.4-40.99) whereas by recombinant Variable Surface Glycoprotein based indirect ELISA was 41.88% (CI at 95%: 37.5-46.3) and 40.35% (CI at 95%: 36.02-44.76) respectively. Climate parameters which influence vector population were extracted from their respective database and were correlated with seroprevalence data. Linear discriminant analysis revealed that air temperature, relative humidity and diurnal temperature range, leaf area index and soil moisture as significant risk factors discriminating seropositive and seronegative data sets classified by indirect ELISA. This study is the first report on seroprevalence of surra in cattle of Mizoram and the situation demands deployment of intervention strategies in order to assess the endemicity of the disease and thereby preventing the economic losses.

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Climatic factors associated with the infection of herds of cattle with bluetongue viruses

1996

Veterinary Research Communications

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The incidence of bluetongue virus infection of 15 cattle herds in Queensland, Australia, was determined by a serum neutralization test. The maximum temperature (degree C), minimum temperature (degree C) and rainfall (mm) data were obtained from the meteorological recording stations closest to each herd. Using unweighted least-squares regression analysis, the best statistical model explaining the most variability in the herd incidence rate included the ratio between the maximum and minimum temperature recorded at both 1 month and 6 months preceding seroconversion, and rainfall recorded at both 2 months and 6 months preceding seroconversion. More than 90% of the variability in the incidence of bluetongue virus infection in the herds was explained by the model, a considerable improvement on previous models that used prevalence data. The prospective nature of the study also supports a strong causal relationship between climatic factors and the occurrence of infection in cattle herds.

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The use of discriminant analysis in predicting the distribution of bluetongue virus in Queensland, Australia

Cited by 10 publications

References 24 publications

Thermal limits of two biting midges, Culicoides imicola Kieffer and C. bolitinos Meiswinkel (Diptera: Ceratopogonidae)

Thermal limits of two biting midges, Culicoides imicola Kieffer and C. bolitinos Meiswinkel (Diptera: Ceratopogonidae)

Seroprevalence of Trypanosoma evansi in cattle and analysis of associated climatic risk factors in Mizoram, India

Climatic factors associated with the infection of herds of cattle with bluetongue viruses

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