[Biosafety and biosecurity in the medical laboratory. Update and trends]. / Biosiguranta si biosecuritatea în laboratorul medical. Actualitati si tendinte.

Biosafety includes the protective measures against the risks of contamination with pathogen germs in the laboratories that handle pathogens, or stock or manipulate potentially contaminated products, or perform microbiological tests for medical or scientific research purposes, as well as the means of protecting the environment and the human collectivities against hazard contaminations that have as starting point these laboratories. Besides, lately, a new notion emerged, that of biosecurity, which refers to the sum of measures designed to protect workers, environment and population against the loss, theft, use and release in the environment of pathogenic biological agents. The work overviews the present concerns for the regulation of these two notions and the way in which a system for the management of the biological risks in a laboratory that handles pathogens should be documented and implemented. The need for the continuous professional training of the staff and for the establishment of individual and collective responsibilities for preventing biosafety incidents and trespassing biosecurity rules are as well emphasized. The main biosafety measures are pointed out and a series of considerations regarding biosafety and bioterrorism in correlation with the medical laboratory are as well mentioned.

Evolution of the Sabin type 1 poliovirus in humans: characterization of strains isolated from patients with vaccine-associated paralytic poliomyelitis.

Attenuated strains of the Sabin oral poliovirus vaccine replicate in the human gut and in rare cases cause vaccine-associated paralytic poliomyelitis (VAPP). Reversion of vaccine strains toward a pathogenic phenotype is probably one of the main causes of VAPP, a disease most frequently associated with type 3 and type 2 strains and more rarely with the type 1 (Sabin 1) strain. To identify the determinants and mechanisms of safety versus pathogenicity of the Sabin 1 strain, we characterized the genetic and phenotypic changes in six Sabin 1-derived viruses isolated from immunocompetent patients with VAPP. The genomes of these strains carried either few or numerous mutations from the original Sabin 1 genome. As assessed in transgenic mice carrying the human poliovirus receptor (PVR-Tg mice), all but one strain had lost the attenuated phenotype. Four strains presented only a moderate neurovirulent phenotype, probably due at least in part to reversions to the wild-type genotype, which were detected in the 5' noncoding region of the genome. The reversions found in most strains at nucleotide position 480, are known to be associated with an increase in neurovirulence. The construction and characterization of Sabin 1 mutants implicated a reversion at position 189, found in one strain, in the phenotypic change. The presence of 71 mutations in one neurovirulent strain suggests that a vaccine-derived strain can survive for a long time in humans. Surprisingly, none of the strains analyzed were as neurovirulent to PVR-Tg mice as was the wild-type parent of Sabin 1 (Mahoney) or a previously identified neurovirulent Sabin 1 mutant selected at a high temperature in cultured cells. Thus, in the human gut, the Sabin 1 strain does not necessarily evolve toward the genetic characteristics and high neuropathogenicity of its wild-type parent.

High diversity of poliovirus strains isolated from the central nervous system from patients with vaccine-associated paralytic poliomyelitis.

To establish the etiology of vaccine-associated paralytic poliomyelitis (VAPP), isolates from the central nervous system (CNS) from eight patients with VAPP were compared with stool isolates from the same patients. The vaccine (Sabin) origin was checked for all of the available isolates. Unique and similar strains were recovered from paired stool and CNS samples for five of the eight VAPP cases and the three wild-type cases included in the study. In the remaining three VAPP cases, the stool samples and, in one case, the CNS samples contained mixtures of strains. In two of these cases an equivalent of the CNS isolate was found among the strains separated by plaque purification from stool mixtures, and in one case different strains were isolated from CNS and stool. This shows that the stool isolate in VAPP might not be always representative of the etiologic agent of the neurological disease. A wide variety of poliovirus vaccine genomic structures appeared to be implicated in the etiology of VAPP. Of nine CNS vaccine-derived strains, four were nonrecombinant and five were recombinant (vaccine/vaccine or even vaccine/nonvaccine). The neuropathogenic potential of the isolates was evaluated in transgenic mice sensitive to poliovirus. All of the CNS-isolated strains lost the attenuated phenotype of the Sabin strains. However, for half of them, the neurovirulence was lower than expected, suggesting that the degree of neurovirulence for transgenic mice is not necessarily correlated with the neuropathogenicity in humans.

Genomic modifications in naturally occurring neurovirulent revertants of Sabin 1 polioviruses.

Five type 1 Sabin-like poliovirus strains were isolated from paralytic cases of poliomyelitis. Their Sabin origin was confirmed by antigenic analysis with monoclonal antibodies and restriction fragment length polymorphism (RFLP) assay. Several nucleotide positions known to play a role in the reversion towards neurovirulence were examined: viz 480, 2741, 6203, 7441. Analysis was performed by enzymatic restriction and partial sequencing of PCR-amplified genomic segments. All the strains bore the reversion G > A at residue 480; in four of the five viruses, only this reversion was found. The fifth strain presented four additional reversions and several new mutations. These results indicate that, during multiplication in the human gut, Sabin 1 poliovirus carrying one or several mutations related to reversion towards neurovirulence can be selected.

[Presence of the rotavirus antigen in newborn infants at maternity hospitals in Moldavia]. / Présence de l'antigène rotaviral de groupe chez des nouveau-nés des maternités de Moldavie.

Studies conducted on 417 feces samples collected from newborn infants from seven maternity homes revealed the presence of rotavirus in 1.2 to 9.5% of the subjects. The infants get infection during the first 24 to 48 hours of life (1.8%) and the positivity rate reaches a peak the 7th day (9.7%). Enteroviruses were found in 3.4% and enterobacteria in 11.8% of the samples.

[Detection of the rotavirus group antigen by a screening test using the ELISA-IC kit in subjects with acute gastroenteritis, at the pediatric services of Moldavia]. / Détection de l'antigène rotaviral de groupe par le test de screening à l'aide de la trousse ELISA-IC chez des sujets atteints de gastro-entérite aiguë, des services de pédiatrie de Moldavie.

The rotaviral antigen was detected by a screening test using the ELISA-IC kit in 17.6% out of 415 children with acute gastroenteritis. The highest frequency (28.9%) was found in children hospitalized in pediatric services with a diagnosis of diarrhoeic disease associated to acute respiratory infection. The rotavirus infection incidence was about three times higher during the cold season than during summer (30.4% versus 10.5%). The 6-11 month age group was the most severely affected.

WHO collaborative studies on poliovirus type 3 strains isolated during the 1968 poliomyelitis epidemic in Poland.

In 1968 in Poland an extensive outbreak of poliomyelitis, caused by type 3 poliovirus, began about four months after small vaccine trials with the Leon 12a(1)b (Sabin) and USOL-D bac vaccine strains had been carried out. Because of the temporal association, and because the first cases appeared in the province in which the USOL-D vaccine trial was carried out, a detailed investigation of the strains isolated from cases in the epidemic was made in four laboratories in an attempt to determine whether they were related to the two vaccine strains or to a "wild" strain. All the studies were made under code. The rct marker was of no help in determining the relationship of the epidemic strains to the vaccine strains. The McBride test and the elution marker test clearly separated the Leon 12a(1)b strains from those from the cases, but were incapable of detecting whether the epidemic strains were related to the USOL-D bac strain or to wild type 3 strains. Thus the studies did not provide valid information on the origin of the epidemic.