Simulating transmission and control of Taenia solium infections using a Reed-Frost stochastic model

The transmission dynamics of the human-pig zoonotic cestode Taenia solium are explored with both deterministic and stochastic versions of a modified Reed-Frost model. This model, originally developed for microparasitic infections (i.e. bacteria, viruses and protozoa), assumes that random contacts occur between hosts and that hosts can be either susceptible, infected or 'recovered and presumed immune'. Transmission between humans and pigs is modelled as susceptible roaming pigs scavenging on human faeces infected with T. solium eggs. Transmission from pigs to humans is modelled as susceptible humans eating under-cooked pork meat harbouring T. solium metacestodes. Deterministic models of each scenario were first run, followed by stochastic versions of the models to assess the likelihood of infection elimination in the small population modelled. The effects of three groups of interventions were investigated using the model: (i) interventions affecting the transmission parameters such as use of latrines, meat inspection, and cooking habits; (ii) routine interventions including rapid detection and treatment of human carriers or pig vaccination; and (iii) treatment interventions of either humans or pigs. It is concluded that mass-treatment can result in a short term dramatic reduction in prevalence, whereas interventions targeting interruption of the life cycle lead to long-term reduction in prevalence.     

A recombinant CHSE-214 cell line expressing an Mx1 promoter-reporter system responds to both interferon type I and type II from salmonids and represents a versatile tool to study the IFN-system in teleost fish

A transgenic cell line for the detection of salmon interferons (IFNs) has been established. It is based on a CHSE-214 cell line containing a reporter construct expressing firefly luciferase under the control of the rainbow trout promoter for the IFN-induced Mx1 gene. This cell line, named CHSE-Mx10, showed IFN-induced luciferase expression after more than 80 passages, confirming the stability of this cell line. Interestingly, the Mx promoter was shown to respond to both salmon IFN-alpha/beta and trout IFN-gamma in a dose-dependent manner, while there was no response to TNF-alpha and IL-1beta. IFN-alpha/beta activity could be measured at a range of 9-150 U/ml, and IFN-gamma showed activity between 10 and 100 ng/ml. The reproducibility of both responses was good. The CHSE-Mx10 reporter system constitutes a versatile tool to study the induction and regulation of IFN signaling in teleost fish. A preliminary study presented herein suggests that both infectious pancreas necrosis virus (IPNV) and salmon pancreas disease virus (SPDV) may block activation of the Mx promoter in CHSE-Mx10 stimulated with IFN-alpha/beta.     

The same allele of translation initiation factor 4E mediates resistance against two Potyvirus spp. in Pisum sativum

Pathogenicity of two sequenced isolates of Bean yellow mosaic virus (BYMV) was established on genotypes of Pisum sativum L. reported to carry resistance genes to BYMV and other potyviruses. Resistance to the white lupin strain of BYMV (BYMV-W) is inherited as a recessive gene named wlv that maps to linkage group VI together with other Potyvirus resistances. One of these, sbm1, confers resistance to strains of Pea seedborne mosaic virus and previously has been identified as a mutant allele of the eukaryotic translation initiation factor 4E gene (eIF4E). Sequence comparison of eIF4E from BYMV-W-susceptible and -resistant P. sativum genotypes revealed a polymorphism correlating with the resistance profile. Expression of eIF4E from susceptible plants in resistant plants facilitated BYMV-W infection in inoculated leaves. When cDNA of BYMV-W was agroinoculated, resistance mediated by the wlv gene frequently was overcome, and virus from these plants had a codon change causing an Arg to His change at position 116 of the predicted viral genome-linked protein (VPg). Accordingly, plants carrying the wlv resistance gene were infected upon inoculation with BYMV-W derived from cDNA with a His codon at position 116 of the VPg coding region. These results suggested that VPg determined pathogenicity on plants carrying the wlv resistance gene and that wlv corresponded to the sbm1 allele of eIF4E.     

What is the Value of a Good Map? An Example Using High Spatial Resolution Imagery to Aid Riparian Restoration

Riparian areas contain structurally diverse habitats that are challenging to monitor routinely and accurately over broad areas. As the structural variability within riparian areas is often indiscernible using moderate-scale satellite imagery, new mapping techniques are needed. We used high spatial resolution satellite imagery from the QuickBird satellite to map harvested and intact forests in coastal British Columbia, Canada. We distinguished forest structural classes used in riparian restoration planning, each with different restoration costs. To assess the accuracy of high spatial resolution imagery relative to coarser imagery, we coarsened the pixel resolution of the image, repeated the classifications, and compared results. Accuracy assessments produced individual class accuracies ranging from 70 to 90% for most classes; whilst accuracies obtained using coarser scale imagery were lower. We also examined the implications of map error on riparian restoration budgets derived from our classified maps. To do so, we modified the confusion matrix to create a cost error matrix quantifying costs associated with misclassification. High spatial resolution satellite imagery can be useful for riparian mapping; however, errors in restoration budgets attributable to misclassification error can be significant, even when using highly accurate maps. As the spatial resolution of imagery increases, it will be used more routinely in ecosystem ecology. Thus, our ability to evaluate map accuracy in practical, meaningful ways must develop further. The cost error matrix is one method that can be adapted for conservation and planning decisions in many ecosystems.     

A mitogenomic approach to the taxonomy of pollocks: <Emphasis Type="Italic">Theragra chalcogramma</Emphasis> and <Emphasis Type="Italic">T. finnmarchica</Emphasis> represent one single species

Background  

The walleye pollock (Theragra chalcogramma) and Norwegian pollock (T. finnmarchica) are confined to the North Pacific and North Atlantic Oceans, respectively, and considered as distinct species within the family Gadidae. We have determined the complete mtDNA nucleotide sequence of two specimens of Norwegian pollock and compared the sequences to that of 10 specimens of walleye pollock representing stocks from the Sea of Japan and the Bering Sea, 2 specimens of Atlantic cod (Gadus morhua), and 2 specimens of haddock (Melanogrammus aeglefinus).