Salivary excretion of rabies virus was evaluated in 14 adult vampire bats (Desmodus rotundus) intramuscularly injected with a large dose (10(6) MICLD50) of vampire rabies virus variant CASS88. Saliva samples were obtained from surviving bats every other day for 30 days, then weekly for 2 months, and finally 1 and 2 years later. Rabies virus was isolated in murine neuroblastoma cells and in randomly selected cases by PCR. Rabies virus was not detected in the saliva of any of the 11 animals that succumbed (somewhat early) to rabies challenge, nor in the control bats. In contrast, virus was detected early, and only once (days 6, 6 and 21) in each of the three animals that survived rabies challenge and remained healthy for at least 2 years after challenge. At that time even vigorous dexamethasone and cyclosporine administration failed to provoke further viral excretion.

No abstract

A field trial of fox vaccination against rabies using a vaccinia-rabies recombinant virus was carried out in Belgium on October 24, 1987. Each vaccine capsule contained a suspension of 10(8) TCID50 of the recombinant virus and was introduced into a chicken head. Each chicken head contained 150 mg of tetracycline as a marker of uptake. Two hundred and fifty heads were distributed in an area of 6 km2 situated within a military zone. The bait uptake was monitored for 15 days after the distribution. Sixty-three per cent of the chicken heads were taken by wild animals within that period. The trial was controlled according to the rules defined by the World Health Organisation.

Puumala hantavirus (PUUV) sequences were recovered from red bank voles (Clethrionomys glareolus) trapped between 1996 and 1998 in four localities of southern Belgium: Thuin, Montbliart, Momignies and Couvin. In addition, three PUUV isolates originating from bank voles trapped in the 1980s in southern (Montbliart) and northern (Turnhout) Belgium were genetically characterized. Analysis of the complete S and partial M segment sequences showed that the Belgian PUUV strains constitute a genetic lineage, distinct from other known PUUV lineages from Europe and Japan. This lineage also includes a wild strain (Cg-Erft) originating from a neighbouring area of Germany. Within the Belgian lineage, geographical clustering of genetic variants was observed. In the Montbliart site, the range of diversity between the most temporally distant strains (from 1986 and 1996-1998) was higher than between those from 1996 and 1998, suggesting slight genetic drift via accumulation of neutral or quasi-neutral substitutions with time.

Optimal activation of T lymphocytes depends on TCR interaction with peptide/MHC complexes in conjunction with costimulatory signals, which are delivered by specialized cells called antigen-presenting-cells (APC). The population of APC is heterogeneous and includes dendritic cells, B cells and macrophages. The family of dendritic cells (DC) is widely distributed in tissues and plays a major role in the induction of primary T-dependent immune responses. The aim of this paper was to isolate and characterize dendritic cells from cattle. Two methods are described that have been used to isolate dendritic cells from bovine peripheral blood. One method involves sequential depletion of other cells, adherence and isolation of low buoyant density cells on Metrizamide column. The second involves enrichment of cells displaying receptors for plasma fibronectin, followed by adherence and separation on Metrizamide. Both preparations were characterized morphologically by flow cytometry and functionally. Both procedures produced enriched populations that did not express molecules typical of T cells (CD3, CD4, CD8, WC1), B cells (sIg, CD21) and monocytes (CD14, Fc gamma 2R). Procedure 2 yielded cells with a typical veiled DC morphology that were highly effective at stimulating allogeneic T cells. Procedure 1 yielded cells that did not have the veiled morphology and were less effective in the MLR which may represent a more immature stage.