12 research outputs found
Transmission and Control of African Horse Sickness in The Netherlands: A Model Analysis
African horse sickness (AHS) is an equine viral disease that is spread by Culicoides spp. Since the closely related disease bluetongue established itself in The Netherlands in 2006, AHS is considered a potential threat for the Dutch horse population. A vector-host model that incorporates the current knowledge of the infection biology is used to explore the effect of different parameters on whether and how the disease will spread, and to assess the effect of control measures. The time of introduction is an important determinant whether and how the disease will spread, depending on temperature and vector season. Given an introduction in the most favourable and constant circumstances, our results identify the vector-to-host ratio as the most important factor, because of its high variability over the country. Furthermore, a higher temperature accelerates the epidemic, while a higher horse density increases the extent of the epidemic. Due to the short infectious period in horses, the obvious clinical signs and the presence of non-susceptible hosts, AHS is expected to invade and spread less easily than bluetongue. Moreover, detection is presumed to be earlier, which allows control measures to be targeted towards elimination of infection sources. We argue that recommended control measures are euthanasia of infected horses with severe clinical signs and vector control in infected herds, protecting horses from midge bites in neighbouring herds, and (prioritized) vaccination of herds farther away, provided that transport regulations are strictly applied. The largest lack of knowledge is the competence and host preference of the different Culicoides species present in temperate regions
Evaluation of the Family Start programme: Synthesis of process and impact evaluation findings
This report provides findings from an evaluation of the Family Start programme (âFamily Startâ), a
voluntary home-visiting programme that supports whÄnau to improve childrenâs health, learning
and relationships, whÄnau circumstances, environment and safety
The use of soluble African horse sickness viral protein 7 as an antigen delivery and presentation system
We have investigated the use of soluble chimeric trimers of the major capsid protein VP7 of
African horse sickness virus (AHSV) as a vaccine delivery system by targeting some of the
natural hydrophilic loops on the VP7 top domain for the insertion of foreign peptides. Key to this
trimer display strategy is the solubility of AHSV VP7 and how the solubility of this hydrophobic
protein can be manipulated by inserting peptides into the top domain. To investigate, we
generated different cloning vectors by inserting multiple cloning sites at three different positions
in the VP7 gene. These modifications inserted six amino acids at the cloning sites and in some
cases this converted VP7 to a largely soluble protein without affecting the ability of the modified
proteins to form trimers. The vectors were used to generate a number of soluble VP7 fusion
proteins including a fusion with a 36 amino acid insert that overlaps important immunological
domains on protein VP1 of foot and mouth disease virus (FMDV) as well as a 110 amino acid
peptide derived from AHSV VP2. Soluble trimers of these fusion proteins were able to elicit a
good insert-specific immune response in guinea pigs. l-Arginine was found to reverse protein
aggregation and was employed as an effective strategy to isolate relatively pure soluble chimeric
VP7 trimers. Another factor that increased VP7 solubility in both wild-type VP7 and one of the
VP7 vector proteins was the substitution of the leucine residue in position 345 of the VP7 Cterminus
with a hydrophilic arginine residue.The work was largely supported by BioPad Bric grant BP050 with additional support from the
National Research Foundation.www.elsevier.com/locate/virusre