ABSTRACT
Due to possible presence and spread of contagious animal viruses via natural sausage casings the international trade in these food products is subject to veterinary and public health requirements. In order to manage these restrictions we determined the effect of casing preservation on four highly contagious viruses for livestock: foot-and-mouth-disease virus (FMDV), classical swine fever virus (CSFV), swine vesicular disease virus (SVDV) and African swine fever virus (ASFV). We used an in vitro 3D collagen matrix model in which cells, infected with the four different viruses were embedded in a bovine collagen type I gel matrix and treated with either saturated salt (NaCl) or phosphate supplemented saturated salt at four different temperatures (4, 12, 20 and 25 °C) during a period of 30 days. The results showed that all viruses were faster inactivated at higher temperatures, but that stability of the various viruses at 4 °C differed. Inactivation of FMDV in the 3D collagen matrix model showed a clear temperature and treatment effect on the reduction of FMDV titres. At 4 and 12 °C phosphate supplemented salt showed a very strong FMDV inactivation during the first hour of incubation. Salt (NaCl) only had a minor effect on FMDV inactivation. Phosphate supplemented salt treatment increased the effect temperature had on inactivation of CSFV. In contrast, the salt (NaCl) treatment only increased CSFV inactivation at the higher temperatures (20 °C and 25 °C). Also SVDV inactivation was increased by phosphate supplemented salt, but salt (NaCl) treatment only resulted in a significant decrease of SVDV titre at a few time points. The ASFV results showed that both salt (NaCl) and phosphate supplemented salt were capable to inactivate ASFV within 48 h. In contrast to the other viruses (FMDV, CSFV and SVDV), ASFV was the most stable virus even at higher temperatures. The results obtained in this in vitro model underline the efficacy of a combined treatment using phosphate supplemented salt and storage at 20 °C or higher for a period of 30 days. This treatment may therefore be useful in reducing the animal health risks posed by spread of contagious animal viruses by international trade of natural sausage casings.
Subject(s)
Meat Products/virology , Phosphates/pharmacology , Sodium Chloride/pharmacology , Virus Inactivation , African Swine Fever Virus/drug effects , Animals , Cattle , Cell Line , Classical Swine Fever Virus/drug effects , Collagen , Enterovirus B, Human/drug effects , Food Contamination/prevention & control , Food Microbiology , Foot-and-Mouth Disease Virus/drug effects , Swine , TemperatureABSTRACT
BACKGROUND: In the Netherlands, 500,000 blood donors are active. Blood of all donors is currently typed serologically for ABO, the Rh phenotype, and K. Only a subset of donors is typed twice for a larger set of red cell (RBC) and/or platelet (PLT) antigens. To increase the direct availability of typed RBCs and PLTs, a high-throughput technique is being developed to genotype the whole donor cohort for all clinically relevant RBC and PLT antigens. STUDY DESIGN AND METHODS: A multiplex polymerase chain reaction was developed to both amplify and fluorescently label 19 gene fragments of RBC and PLT antigens in one reaction. To test the setup of the genotyping method by microarray, a pilot study with human PLT antigen (HPA)-typed donor samples was performed. On each slide, 12 arrays are present containing 20 probes per PLT antigen system (28 for HPA-3). The allele-specific oligohybridization method was used to discriminate between two different alleles. RESULTS: Two blinded panels encompassing 94 donors were genotyped for HPA-1 through -5 and -15; no discrepancies were found compared to their serologic typing (HPA-1, -2, -3, -4, and -5) and genotyping (HPA-15; TaqMan, Applied Biosystems). CONCLUSION: This study shows that the HPA microarray provides a reliable and fast genotyping procedure. With further development an automated throughput for complete typing of large donor cohorts can be obtained.
