In the course of certain recent experiments (1) it was observed that the chance of a virus preparation causing infection in an animal could not be predicted solely by the amount of virus injected and by the host's resistance but was influenced by still another variable. I t seemed possible that this variable might be the tissue mass (number of cells) exposed to each virus particle. If this were...

newcastle disease is one of the most important diseases of poultry. it usually causes a great loss inpoultry industry and domestic village chickens. since domestic chickens in villages are free ranging for food,the chance of their contact with wild birds that may act as reservoirs is high. to determine the role ofdomestic chickens in the epizootiology of newcastle disease virus in villages of i...

The presence or evolution of immune escape variants has been proposed to account for the failure of recombinant envelope vaccines to protect macaques against challenge with simian immunodeficiency virus (SIVmac). To address this issue, two groups of three cynomolgus macaques were immunized with recombinant SIV Env vaccines using two different vaccine schedules. One group of macaques received fo...

The biguanide concentration of polyhexamethylene biguanide hydrochloride (PHMB-HCl) was measured by non-aqueous titration with HClO4, argentometric titration, the Kjeldhal method, and colloidal titration. The summation value of non-aqueous titration and argentometric titration corresponded to two titrable nitrogens in five nitrogens per one unit of PHMB-HCl, and consisted with the result of the...

The establishment of a successful plaque method for counting infectious virus particles by Dulbecco (1952), with subsequent refinements by Dulbecco and Vogt (1953, 1954a), makes it possible to quantitatively assay animal viruses with a high degree of accuracy in a manner comparable to assays of bacterial viruses. Two methods of assay commonly used in characterizing any particular Newcastle dise...

Orf virus, a member of the Parapoxvirus genus, causes a contagious pustular dermatitis in sheep, goats, and humans. Previous studies have demonstrated the activity of (S)-1-[3-hydroxy-2-(phosphonomethoxy)propyl]cytosine (HPMPC; cidofovir; Vistide) against orf virus in cell culture and humans. We have evaluated a broad range of acyclic nucleoside phosphonates (ANPs) against several orf virus str...

Touching of contaminated objects and surfaces is a well-known method of virus transmission. Once they are attached to the hands, viruses can easily get adsorbed and initiate infection. Hence, disinfection of frequently touched surfaces is of major importance to prevent virus spreading. Here we studied the antiviral activity of a glucoprotamin-containing disinfectant against influenza A virus an...

The infectivity of rotavirus particles is dependent on proteolytic cleavage of the outer capsid protein, VP4, at a specific site. This cleavage event yields two fragments, identified as VP5* and VP8*. It has been hypothesized that the particle is more stable, but non-infectious, when VP4 is in the uncleaved state. Uncleaved VP4 and the resultant increased stability might be advantageous for the...