Effect of membrane length, membrane resistance, and filtration conditions on the fractionation of milk proteins by microfiltration.

We investigated the fractionation of casein micelles and the whey protein ß-lactoglobulin (ß-LG) of skim milk by crossflow microfiltration (0.1 µm) for the first time by a novel approach as a function of membrane length and membrane resistance. A special module was constructed with 4 sections and used to assess the effects of membrane length by measuring flux and ß-LG permeation (or transmission) as a function of transmembrane pressure and membrane length. Depending on the position, the membranes were partly controlled by a deposit layer. A maximum for ß-LG mass flow through the various membrane sections was found, depending on the position along the membrane. To study the effect of convective flow toward the membrane, membranes with 4 different intrinsic permeation resistances were assessed in terms of the permeation and fouling effects along the flow channel. From these findings, we derived a ratio between transmembrane pressure and membrane resistance, which was useful in reducing the effect of deposit formation and, thus, to optimize the protein permeation. In addition, the fouling effect was investigated in terms of reversible and irreversible fouling and, in addition, by differentiation between pressure-induced fouling and adsorption-induced (pressure-independent) fouling, again as a function of membrane length.

[Emergent pathogens, international surveillance and international health regulations (2005)]. / Les pathogènes émergents, la veille internationale et le Règlement sanitaire international (2005).

In order to address the vitality of the microbial world, to detect emerging infectious diseases, to determine their potential threat to public health, and to establish effective interventions, the World Health Organization (WHO) has developed and coordinates the Global Outbreak Alert and Response Network (GOARN) which connects several surveillance networks. Some of these networks are specific to epidemic-prone diseases, such as influenza, dengue, yellow fever or meningitis. Others were especially designed to track unusual events--such as the emergence of SARS--that are naturally-occurring, accidental, or deliberately created (biological weapons, bio-terrorism). Lastly, a special effort is being made at the international level to modernize the International Health Regulations, now obsolete, and to support all the countries in the reinforcement of their outbreak alert and response capacity.

[Outbreak of Ebola hemorrhagic fever in the Republic of the Congo, 2003: a new strategy?]. / L'épidémie de fièvre hémorragique à virus Ebola en République du Congo, 2003: une nouvelle stratégie?

This article describes the last Ebola haemorrhagic fever (EHF) outbreak that occurred in the Cuvette Ouest Region of the Republic of Congo from January to April 2003. Epidemiological study demonstrated that the first patient, in whom diagnosis was made retrospectively, became ill on December 25, 2002. Subsequently until May 7, 2003, a total of 143 cases were recorded in the Mbomo and Kéllé health districts including 129 fatalities. Thirteen cases were laboratory confirmed and 130 were epidemiologically linked. Fifty-three percent of patients were male. Age ranged form 5 days to 80 years. Transmission involved direct contact with an infected person especially within families. Epidemiological data traced introduction of Ebola virus into the population to three primary cases mainly involving hunters. In all three cases development of the disease followed contact with non-human primates (gorillas) and other mammals (antelope) that had either been killed or found dead. Three health care workers were infected during the epidemic but nosocomial transmission played a minor role in the epidemic. On June 5, the Minister of Health and Population of the Congo Republic officially declared that the outbreak of EHF was over in the Cuvette Ouest Region. The last case was recorded on April 22 in the small village of Ndjoukou.

Intervention epidemiology training: a European perspective.

Within the widening European Union, large-scale movements of people, animals and food-products increasingly contribute to the potential for spread of communicable diseases. The EU was given a mandate for public health action only in 1992, under the Treaty of European Union ("Maastricht Treaty"), which was broadened in the 1997 with the Treaty of Amsterdam. While all EU countries have statutory requirements for notifying communicable diseases, national and regional communicable disease surveillance practices vary considerably. The Network Committee (NC) for the Epidemiological Surveillance and Control of Communicable Diseases in the EU was established in 1998 to harmonise these activities.

Day-care and meningococcal disease in young children.

The Republic of Ireland has the highest incidence of meningococcal disease in Europe with 40% of all cases occurring in children under the age of 5 years. Attending day-care increases the risk of certain infections, including Haemophilus influenzae type b (Hib) meningitis. The risk of meningococcal disease associated with day-care is not known. We conducted a case-control study among pre-school children with 130 laboratory-confirmed cases and 390 controls, matched on age, gender and place of residence, to determine if day-care attendance was a risk factor for meningococcal disease. Multivariate analysis showed that day-care attenders had a lower risk of disease than non-attenders (OR 0.3, 95% CI 0.1-0.7) whereas the number of adults in a household, and household crowding were independent risk factors for disease. Asymptomatic carriers of Neisseria meningitidis are the main source of transmission and these carriers are usually adults. Regular day-care attendance may reduce this risk by removing children from close and prolonged contact with adults.

Rumors of disease in the global village: outbreak verification.

Emerging infectious diseases and the growth of information technology have produced new demands and possibilities for disease surveillance and response. Increasing numbers of outbreak reports must be assessed rapidly so that control efforts can be initiated and unsubstantiated reports can be identified to protect countries from unnecessary economic damage. The World Health Organization has set up a process for timely outbreak verification to convert large amounts of data into accurate information for suitable action. We describe the context and processes of outbreak verification and information dissemination.

An outbreak of multidrug-resistant Salmonella typhimurium food poisoning at a wedding reception.

An outbreak of gastrointestinal illness among 127 persons attending a wedding reception in Dublin was investigated. One hundred and fifteen wedding guests were interviewed and information obtained about demographic and clinical characteristics, and food consumed at the reception. Faecal samples from ill guests were submitted for microbiological examination and environmental investigations conducted at the catering facilities. Fifty-eight cases (diarrhoea within three days after having eaten at the reception) were identified. Forty-six cases submitted stool samples, of which 39 were culture positive for Salmonella typhimurium. Two isolates were phage-typed and found to be DT 104. Turkey was identified as a potential vehicle for this outbreak. A sample of litter from young birds at the poultry farm which had supplied the turkeys also tested positive for Salmonella Typhimurium DT104. In the Republic of Ireland S.typhimurium accounts for almost 50% of all human salmonella isolates. Epidemiological and microbiological studies which relate the human and animal spectrum of this disease need to be undertaken as a priority.

7-Deaza-2'-deoxyadenosine and 3-deaza-2'-deoxyadenosine replacing dA within d(A6)-tracts: differential bending at 3'- and 5'-junctions of d(A6).d(T6) and B-DNA.

7-Deaza-2'-deoxyadenosine (1, c7Ad) and 3-deaza-2'-deoxyadenosine (2, c3Ad) have been incorporated into d(AAAAAA) tracts replacing dA at various positions within oligonucleotides. For this purpose suitably protected phosphonates have been prepared and oligonucleotides were synthesized on solid-phase. The oligomers were hybridized with their cognate strands. The duplexes were phosphorylated at OH-5' by polynucleotide kinase and self-ligated to multimers employing T4 DNA ligase. Oligomerized DNA-fragments were analyzed by polyacrylamide gel electrophoresis and the bending was determined from anomalies of electrophoretic mobility. Replacement of dA by c3Ad decreased the bending more than replacement by c7Ad. Reduction of bending was much stronger when the modified nucleosides replaced one or several dA residues at the 3'-site of an d(AAAAAA)-tract whereas replacement at the 5'-site showed no significant influence [1, 2].