Publications

Coccidiosis is an economically important disease in chickens, caused by infection with Eimeria species parasites. Diagnosis of coccidiosis is frequently based on oocyst enumeration in pooled faecal samples or litter. In studies on infection dynamics and for monitoring in the field, samples from individual chickens may be more appropriate as these support the determination of infection status of individual birds and more accurately reflect oocyst output at time of sampling. Faecal samples from individual birds can be collected, but the counting procedure limits the number of samples that can be processed and unequivocal microscopic differentiation between Eimeria species is very difficult. A test that overcomes these drawbacks would improve efficiency and quality of the diagnosis. The aim of this study was to compare two methods for Eimeria oocyst quantification in samples from individual birds. A real-time PCR that quantifies oocysts in cloacal swabs (qPCR) and oocyst counts in single droppings were compared to the standard procedure of oocyst counts in bulked 24 h faeces. Faecal samples were collected daily from 30 broiler chickens, inoculated with different doses of Eimeria acervulina. The three techniques produced comparable oocyst counts for all inoculation doses. Single dropping counts are applicable for small sample sizes and when a single Eimeria species is used. For larger sample sizes qPCR is preferable as it can be carried out on samples that have been frozen for storage. Furthermore, qPCR can identify and quantify different Eimeria species, which makes it a valuable diagnostic tool for field or experimental work.

This publication bears 82 authors including Michael Watson (IAHC).

Background: The chemokine and chemokine receptor families play critical roles in both the healthy and diseased organism mediating the migration of cells. The chemokine system is complex in that multiple chemokines can bind to one chemokine receptor and vice versa. Although chemokine receptors have been well characterised in humans, the chemokine receptor repertoire of cattle is not well characterised and many sequences are yet to be experimentally validated. Results: We have identified and sequenced bovine homologs to all identified functional human chemokine receptors. The bovine chemokine receptors show high levels of similarity to their human counterparts and similar genome arrangements. We have also characterised an additional bovine chemokine receptor, not present in the available genome sequence of humans or the more closely related pigs or horses. This receptor shows the highest level of similarity to CCR1 but shows significant differences in regions of the protein that are likely to be involved in ligand binding and signalling. We have also examined the mRNA abundance levels of all identified bovine chemokine receptors in mononuclear phagocytic cells. Considerable differences were observed in the mRNA abundance levels of the receptors, and interestingly the identified novel chemokine receptor showed differing levels of mRNA abundance to its closest homolog CCR1. The chemokine receptor repertoire was shown to differ between monocytes, macrophages and dendritic cells. This may reflect the differing roles of these cells in the immune response and may have functional consequences for the trafficking of these cells in vivo. Conclusions: In summary, we have provided the first characterisation of the complete bovine chemokine receptor gene repertoire including a gene that is potentially unique to cattle. Further study of this receptor and its ligands may reveal a specific role of this receptor in cattle. The availability of the bovine chemokine receptor sequences will allow further characterisation of the function of these genes and will confer wide-reaching benefits to the study of this important aspect of the bovine immune response.

Developmental lesions of the central nervous system (CNS) have been described associated with transplacental infection with bluetongue virus (BTV) in cattle (MacLachlan and others 1985) and sheep (Osburn 1972). In the past, the development of these deformations was mostly associated with laboratory-adapted BTV strains, in particular live attenuated vaccine virus strains (Schultz and Delay 1955, Kirkland and Hawkes 2004). However, in 2008, reports from northern European countries revealed an upsurge of similar CNS lesions in calves and lambs following the infection of pregnant cows and ewes with a field strain of BTV serotype 8 (Desmecht and others 2008, Vercauteren and others 2008, Wouda and others 2008). This short communication describes the clinical, virological and pathological findings in two calves born in England during 2008 to cows infected with BTV while pregnant in autumn 2007, and reports bluetongue-associated hydranencephaly, with an affected 'dummy' calf surviving until seven months old.