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Following a school ski-trip to Austria from 10 to 18/02/2017, nine of 25 participants of the group from Lower Saxony (Germany) developed gastroenteritis. The students and teachers (17–41 years) shared meals in a hotel. Active case finding revealed further cases among German school groups from North Rhine-Westphalia and Schleswig-Holstein, staying at the same hotel in February 2017. We conducted two retrospective cohort studies using self-administered questionnaires on clinical symptoms and food consumption. We defined a case as a trip participant in February 2017, staying at the aforementioned hotel and developing diarrhoea, vomiting or abdominal pain during or within ten days after the trip and/or who had a stool sample tested positive for STEC within four weeks after the trip. During the outbreak investigation, Austrian authorities detected that unlabeled raw cow milk delivered by a dairy farm had been offered at the hotel for breakfast during January and February 2017. Stool samples of participants, samples of milk served in the hotel and fecal samples of various animals kept at the milk-delivering farm were examined by culture and polymerase chain reaction. STEC isolates were typed using Pulsed-field Gel Electrophoresis (PFGE) and Whole-Genome Sequencing (WGS). All 25 participants from Lower Saxony completed the questionnaire on symptoms and milk consumption; 14 were cases (56%). Thirteen of 20 participants who had consumed cold milk fell ill (risk ratio (RR): 3.25; 95%-confidence interval (CI): 0.55–19.32). Of 159 trip participants from North Rhine-Westphalia, 81 completed the questionnaire (51%), 25 were cases (31%); RR for cold milk was 2.11 (CI: 0.89–5.03). The combined RR for cold milk in both groups was 2.49 (CI: 1.16–5.35). Shiga toxin 1a-gene and eaeA-gene positive STEC O103:H2 were detected in nine of 32 patients’ stool samples and in two of 18 dairy farm cattle. Nine isolates from human stool samples and two isolates from cattle fecal samples yielded the same strain with an almost identical PFGE-pattern and WGS-profile. Microbiological and epidemiological evidence identified raw cow milk as the vehicle. Results may have been compromised by misclassification of cases due to a recall bias and mild symptoms. As a result of this outbreak investigation, the Austrian authorities enforced Austrian law in the hotel, to provide milk only when pasteurized. We recommend re-emphasizing the risk of raw milk consumption to providers.

With the intention to deepen the knowledge of the vertical transmission of particular subtypes of Salmonella enterica from “the stable to the table” a case1–case2 analysis in Lower Saxony, Germany, was conducted. The data collection was based on standardised telephone interviews with 1741 Salmonella case persons. Single-factor-analyses revealed statistically significant associations between S. Typhimurium infections and animal keeping (odds ratio (OR): 1.4; 95%-Confidence-interval (CI): 1.2–1.7), especially rodents (OR 1.5; CI 1.2–2.1), and with consumption of meat (OR 1.9; CI 1.3–2.8), raw ground pork (OR 3.0; CI 2.1–4.2) and uncooked pork sausage (OR 2.1; CI 1.6–2.9). The S. Typhimurium phage type DT 104 was associated most with consumption of uncooked pork sausage (OR 3.6; CI 1.3–8.5). Multiple logistic regression analyses confirmed the associations between S. Typhimurium infection and consumption of raw ground pork and with animal contact. The results circumstantiate the assumption of raw pork products still being a relevant source for S. Typhimurium infections in Germany. Therefore, it is recommended to intensify efforts to reduce salmonella infections caused by raw pork products. S. Enteritidis infection was associated statistically significantly with travelling abroad (OR 2.1; CI 1.6–3.3), consumption of raw tomatoes (OR 1.8; CI 1.5–2.1), dried herbs (OR 2.1; CI 1.0–1.8), and undercooked eggs (OR 1.3; CI 1.1–1.6) compared with other serovars. These results were confirmed in multiple logistic regression analyses, as well.

In May 2011 one of the worldwide largest outbreaks of haemolytic uraemic syndrome (HUS) and bloody diarrhoea caused by Shiga toxin-producing Escherichia coli (STEC) serotype O104:H4 occurred in Germany. One of the most affected federal states was Lower Saxony. We present the investigation of a cluster of STEC and HUS cases within this outbreak by means of a retrospective cohort study. After a 70th birthday celebration which took place on 7th of May 2011 among 72 attendants seven confirmed cases and four probable cases were identified, two of them developed HUS. Median incubation period was 10 days. Only 35 persons (48.6%) definitely answered the question whether they had eaten the sprouts that were used for garnishing the salad. Univariable analysis revealed different food items, depending on the case definition, with Odds Ratio (OR)>1 indicating an association with STEC infection, but multivariable logistic regression showed no increased risk for STEC infection for any food item and any case definition. Sprouts as the source for the infection had to be assumed based on the results of a tracing back of the delivery ways from the catering company to the sprouts producer who was finally identified as the source of the entire German outbreak. In this large outbreak several case-control studies failed to identify the source of infection.

Three micro solid phase immunoassays (a micro-SPRIA and two ELISA techniques) were developed and tested for the detection of anti-HBs antibodies. Two different crosslinkers (glutaraldehyde and N-succinimidyl 3-(2-pyridyldithio) propionate) were used to couple a goat anti-mouse IgG reagent to alkaline phosphatase for use as enzyme-labeled probes in the two ELISA tests. With the latter crosslinker, a defined conjugate with a 1 : 1 antibody-enzyme molar ratio was obtained. The sensitivities of micro-SPRIA and the two types of ELISA were compared to that of the commercial solid phase radioimmunoassay AUSAB test. All three microtests were significantly more sensitive than theAUSAB test. The ELISA using the glutaraldehyde cross-linked conjugate was 3—5 times less sensitive than micro-SPRIA, while the ELISA using the disulfide-linked conjugate was 2.6–4.0 times more sensitive than micro-SPRIA.

Twelve subhuman primates [eight baboons ( Papio anubis ) and four rhesus ( Macaca mulatta )] were inoculated with varying amounts of human plasma containing HB s Ag with Dane particles. Serial blood specimens and liver, kidney, bone marrow, and lymph node biopsies were obtained from each animal over 10–12 mo. No measurable evidence of HB s Ag production was observed in any animal after the initial clearance of antigen, although the presence of anti-HB s in most of the animals studied might have precluded its detection. Two baboons developed progressive focal glomerulonephritis with mesangial alterations over a 4- to 10-mo period of time. Liver biopsies from these baboons and one rhesus monkey revealed the presence of 26-nm intranuclear particles in the hepatocytes at 4 mo postinoculation. The intranuclear particles were similar in morphology and in size to the cores of Dane particles. Kinetic analysis of antigen clearance implied a rapid uptake of HB s Ag from the blood to the liver and spleen over an 8 to 24-hr period of time and an in vivo clearance rate ( T 1 2 ) of 28.2 hr.

A computer program was developed for use on an Apple IIe that utilized the parameters developed by Hopp and Woods (T. P. Hopp and K. R. Woods, 1983, Mol. Immunol. 20, 483-489) for predicting the hydrophilic regions of a given protein. This program will produce a listing of the hydrophilic sequence averages and graphically illustrates the peak areas. The hydrophilic averages over a hexapeptide length can be used to predict protein structure. In conjunction with the Chou-Fasman predictive scheme for protein secondary structure determination, the possible antigenic determinants for the envelope glycoprotein of three viruses isolated from patients with acquired immunodeficiency syndrome (AIDS) were predicted. These predicted determinants could be used to generate synthetic peptides that represent a potential vaccine preparation or in developing a diagnostic assay that specifically detects the agent.

A polyamide-based solid-phase support containing an acid-stable p-(oxymethyl)benzoic acid handle to anchor the COOH-terminal amino acid was utilized in the production of synthetic peptides analogous to amino acid sequences 503-532 from the human immunodeficiency virus (HIV) envelope glycoprotein. The resin-bound peptide was used to induce an antibody response to the native form of glycoprotein 120 in both rabbits and mice. This epitope was detected on the surface of HIV-infected cells and was capable of inducing an in vitro neutralizing HIV antibody response. In addition, sera from some individuals exposed to HIV react with this peptide bound to the resin in a solid-phase immunoassay. These data indicate that we have identified a neutralizing antigenic determinant present on the amino-terminal glycoprotein 120 subunits of HIV by utilizing resin-bound synthetic peptides.

A sensitive, specific immunoassay for detection of hepatitis B surface antigen (HBsAg) is described. The assay combines enzyme-linked immunosorbent assay and solid-phase radioimmunoassay and is termed enzyme potentiated radioimmunoassay (EPRIA). HBsAg was quantitated by enzymatic conversion of L -[14C]glutamic acid to 14CO2 and gamma-aminobutyric acid by glutamate decarboxylase (GDC) conjugated with goat anti-HBs IgG. Conjugation of IgG and GDC was by a thiol-disulfide bond exchange reaction after reacting N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP) with each reagent. A positive/negative ratio of 2.2 was established as significant by examination of 40 normal sera negative for HBsAg. This value was the mean cpm plus 3 standard deviations. By an identical statistical analysis of sensitivity, EPRIA was found to be approximately 100-fold more sensitive than Austria II (Abbott Laboratories, North Chicago, IL).

The nature of the receptor site responsible for the hemagglutinating activity of adenoviruses was investigated by oxidation of viral antigen preparations and purified virus with sodium metaperiodate. Low concentrations of periodate reduced the hemagglutinating activity of adenovirus (Ad) types 7 and 14, while 25- and 50-fold higher levels of periodate were required to alter the activity of the Ad-2 hemagglutinin. It was also noted that a similar relative sensitivity was observed in the loss of infectivity when purified Ad-2 or Ad-7 virions were oxidized with periodate. Periodate oxidation had no effect on the antigens associated with the hexon. Immunization of animals with oxidized and control preparations of unfractionated antigens, purified pentons or purified virus substantiated the conclusion that the site affected by periodate oxidation was associated with the penton. Animals immunized with oxidized material produced only 4–7% as much hemagglutinin-inhibiting antibody as those which were immunized with control material. However, neutralizing and group-specific complement-fixation antibody titers were not substantially affected by oxidizing the immunizing material. While the mild oxidation conditions employed in the study indicate the possibility that a carbohydrate moiety is associated with the hemagglutinin-reactive site, they are also consistent with the alternative possibility that certain amino acid residues such as those of serine, threonine or cysteine may be essential for the reactive site.

The biotin/avidin system was incorporated into the enzyme-linked immunosorbent assay (ELISA) technique to increase the sensitivity of the standard ELISA for the detection of mouse antibody to hepatitis B surface antigen ((anti-HBs and HBsAg, respectively). Two biotin/avidin ELISA designs were studied. In both assays, 96-well polystyrene plates were coated with HBsAg, post-coated with 0.5% gelatin and incubated with dilutions of mouse anti-HBs. In the biotin/avidin (BA) ELISA, reagents were added to antibody reacted wells in the following sequence: biotinylated goat anti-mouse IgG (b-GAMG), avidin-alkaline phosphatase (Av-AP) and substrate. The order of reactants after mouse antibody in the biotin/avidin/biotin (BAB) ELISA was b-GAMG, avidin, biotinylated alkaline phosphatase (b-AP) and substrate. The sensitivities of BA ELISA, BAB ELISA and a standard ELISA using a glutaraldehyde conjugated goat anti-mouse enzyme were compared to AUSAB (a commercial radioimmunoassay) using a panel of 23 mouse anti-HBs sera. All 3 ELISAs were more sensitive than AUSAB; the standard ELISA, BAB ELISA and BA ELISA were respectively 50, 1173 and 4134 times more sensitive than AUSAB for detection of mouse anti-HBs activity.

The amino acid composition was determined on the proteins of naked nucleocapsids from several isolates of herpesvirus types 1 (HSV-1) and 2 (HSV-2). The viral nucleocapsids were isolated from whole infected cell lysates and partially purified by treatment with Nonidet P-40 followed by centrifugation through a discontinuous sucrose gradient. The partially purified virions were freed of residual fragments of envelope by treatment with a combination of deoxycholate and Tween-40. Highly purified HSV-1 and HSV-2 nucleocapsids had a similar amino acid composition. Arginine was not present in unusually high levels in the HSV nucleocapsid.