Effective vaccination against rabies in puppies in rabies endemic regions.

In rabies endemic regions, a proportionally higher incidence of rabies is often reported in dogs younger than 12 months of age, which includes puppies less than 3 months of age; this presents a serious risk to public health. The higher incidence of rabies in young dogs may be the effect of low vaccination coverage in this age class, partly as a result of the perception that immature immune systems and maternal antibodies inhibit seroconversion to rabies vaccine in puppies less than three months of age. Therefore, to test this perception, the authors report the virus neutralising antibody titres from 27 dogs that were vaccinated with high quality, inactivated rabies vaccine aged three months of age and under as part of larger serological studies undertaken in Gauteng Province, South Africa, and the Serengeti District, Tanzania. All of these dogs seroconverted to a single dose of vaccine with no adverse reactions reported and with postvaccinal peak titres ranging from 2.0 IU/ml to 90.5 IU/ml. In light of these results, and the risk of human beings contracting rabies from close contact with puppies, the authors recommend that all dogs in rabies endemic regions, including those less than three months of age, are vaccinated with high quality, inactivated vaccine.Funding for the study in Zenzele was provided by the International Fund for Animal Welfare (IFAW) and World Animal Protection (WAP). Funding for the study in Tanzania was provided by the RCVS Small Grant Programme and the University of Edinburgh Small Grant Scholarship Program. Dog vaccines for the Serengeti study were donated by MSD Animal Health. Partial funding for the APHA was provided by the UK Department for Environment and Rural Affairs (Project SV3500). JW receives support from the Alborada Trust and the Research and Policy for Infectious Disease Dynamics Program of the Science and Technology Directorate, Department of Homeland Security, Fogarty International Centre, National Institute of Health.This is the author accepted manuscript. The final version is available from BMJ Group via http://dx.doi.org/10.1136/vr.10297

Solid-liquid mass transfer during leaching of calcium from dilute slurries of flyash

Flyashes obtained by burning Curragh and Tarong coal were air elutriated into seven size fractions. Samples were then leached with deionised water in shaken and stirred vessels. All size fractions were leached in an orbital shaker at 1:25 ash water ratio. The results suggest that ions from a surface shell and from the particle interior make distinct contributions to the conductivity of the leachate. The fine fractions (d ~ 2 microns) were also leached in an unbaffled turbine mixer at a minimum speed, so that the particles remained in suspension. The leaching of calcium as calcium hydroxide into the diffuse double layer which forms around the negatively charged particles was examined. A mass transfer model was developed, based on rate expressions derived for the transport of calcium as calcium hydroxide from the surface of the particle into the diffuse double layer, from the diffuse double layer into the boundary layer and from the boundary layer into the bulk solution. Changes in the thickness of the diffuse double layer were taken into consideration. The model assumes rapid leaching of ions from the surface shell and a uniform calcium concentration across the diffuse double layer. From the experimentally measured concentration data for calcium ions in the diffuse double layer and in the bulk solution, transport values for the model were deduced. It was found that mass transfer from the surface of the flyash into the diffuse double layer is the rate controlling step