An Hasidic Jewish community has experienced recurrent hepatitis A outbreaks since 1980. To assess risk factors for illness during a 1985–6 outbreak, the authors reviewed case records and randomly selected 93 households for an interview and serologic survey. In the outbreak, 117 cases of hepatitis A were identified, with the highest attack rate (4·2%) among 3–5 year olds. Among the survey households, the presence of 3–5 year olds was the only risk factor that increased a household's risk of hepatitis A (indeterminant relative risk, P=0·02). Furthermore, case households from the outbreak were more likely to have 3–5 year olds than were control households from the survey (odds ratio=16·4, P<0·001). Children 3–5 years old were more likely to have hepatitis A and may have been the most frequent transmitters of hepatitis A in this community. Hepatitis A vaccination of 3–5 year olds can protect this age group and might prevent future outbreaks in this community.

An M-antibody capture radioimmunoassay (MACRIA) for anti-rubella IgM was developed. Under optimum conditions positive serum specimens bound up to 20 times as much radioactivity as negative specimens. Positive reactions were expressed in arbitrary units/ml by comparison with a calibration curve derived from results obtained with dilutions of a standard serum.

The specificity of the assay was confirmed by testing IgM and IgG rich fractions of positive sera. One hundred and forty specimens from blood donors, patients whose sera contained rheumatoid factor and patients with acute, non-rubella, virus infections were tested by MACRIA. No significant non-specific reactions were detected.

Paired sera from acute rubella (25 patients) and individual sera from suspected rubella (69 patients) were tested for anti-rubella IgM by MACRIA and by haemagglutination inhibition following sucrose-density-gradient fractionation. There was close agreement between the two methods. The capture assay was more sensitive and could be used to detect the weak IgM response in women given RA 27/3 vaccine. After the natural infection, the MACRIA was strongly positive for two months and remained weakly so for a further two months. Repeat testing of sera demonstrated good reproducibility of the assay.

MACRIA proved a simple, sensitive and specific test for anti-rubella IgM and compared favourably with currently used techniques.

For Salmonella typhimurium from humans in England and Wales, the incidence of multiple resistance more than doubled over the 8-year period 1981–8 and, over the next 2 years, increased by a further 7%. From 1981 to 1988 both resistance and multiple resistance also increased significantly in S. virchow and although multiple resistance did not increase over the next 2 years, the overall incidence of resistance has continued to rise. In 1990 the majority of S. typhimurium from cattle were multiply-resistant and the occurrence of such resistance has quadrupled since 1981. Multiple resistance has also increased in S. typhimurium from pigs and, to a lesser extent, from poultry. In contrast, multiple resistance has remained uncommon in the poultry-associated serotype S. enteritidis. For S. virchow, multiple resistance was common in a phage type frequently associated with poultry meat imported from France.

The continuing use of a range of different antimicrobials in calf husbandry has been an important factor in promoting the emergence of multiply-resistant strains of S. typhimurium in cattle. In contrast, multiple resistance has remained rare in those serotypes associated with poultry, where the use of such antimicrobials has been less intensive.

It is hoped that recent recommendations discouraging, in veterinary medicine, the prophylactic use of antibiotics with cross resistances to those used in human medicine will result in a reduction in the occurrence of multiresistant strains in food animals and subsequently in humans.

Surveillance systems for varicella in Europe are highly heterogeneous or completely absent. We estimated the varicella incidence based on seroprevalence data, as these data are largely available and not biased by under-reporting or underascertainment. We conducted a systematic literature search for varicella serological data in Europe prior to introduction of universal varicella immunization. Age-specific serological data were pooled by country and serological profiles estimated using the catalytic model with piecewise constant force of infection. From the estimated profiles, we derived the annual incidence of varicella infection (/100·000) for six age groups (<5, 5–9, 10–14, 15–19, 20–39 and 40–65 years). In total, 43 studies from 16 countries were identified. By the age of 15 years, over 90% of the population has been infected by varicella in all countries except for Greece (86·6%) and Italy (85·3%). Substantial variability across countries exists in the age-specific annual incidence of varicella primary infection among the <5 years old (from 7052 to 16 122 per 100 000) and 5–9 years old (from 3292 to 11 798 per 100 000). The apparent validity and robustness of our estimates highlight the importance of serological data for the characterization of varicella epidemiology, even in the absence of sampling or assay standardization.

We examined stool specimens for viral pathogens from 50 children referred to hospital due to acute gastroenteritis (AGE) resulting from consuming drinking water contaminated with sewage in a Finnish community using PCR methods. Rotavirus was detected in 33 (66%), human calicivirus in 31 (62%), and both in 40% of cases. Of the caliciviruses, 20/31 (65%) were noroviruses and 11 (35%) sapoviruses. Furthermore, Aichi virus was detected in 25 (50%), adenovirus in six (12%) and bocavirus in four (8%) cases. Campylobacter jejuni was present in 20 (61%) and Salmonella in four (12%) of the 33 stools cultured for bacteria. On a 20-point scale median severity score of AGE in the 28 hospitalized children was 17; the severity was similar regardless of viruses detected. Bloody diarrhoea occurred only when C. jejuni was present. To conclude, massive exposure to several AGE viruses caused mixed infections and severe AGE regardless of the aetiological agents.

Each year, countries that participate in the European Surveillance Scheme for Travel Associated Legionnaires' Disease (EWGLINET) are requested to complete a set of standardized reporting forms that provide epidemiological and microbiological information on the total number of cases (non-travel as well as travel-related cases) detected in their country. Trends at the national and aggregated European level have been analysed for 2000–2002. For this period, 10322 cases of Legionnaires' disease were reported and national infection rates ranged from 0 to 34·1 cases per million population. A total of 189 outbreaks were associated with nosocomial infection, community exposure or travel. The upward trend in diagnosis through the urinary antigen detection test has resulted in a higher ascertainment of cases in many countries. However, the decline in diagnosis by culture of the organism is likely to severely hamper outbreak investigations in the future if fewer clinical isolates are available for matching with environmental isolates. This important data-set has been used for studying the effectiveness of surveillance and legionella control and prevention programmes within Europe.

This study determined the prevalence of the eaeA gene and its relationship to serotype and type of verotoxin produced in a collection of 432 verotoxigenic Escherichia coli (VTEC) obtained from the faeces of healthy cows and calves in a systematic random survey involving 80 dairy farms in Southwest Ontario. A PCR amplification procedure involving primer pairs which target the conserved central region of the O157:H7 eaeA. gene showed that 151 (35·2%) strains were positive for the eaeA gene. All isolates (9–21 for each O group) of O groups 5, 26, 69, 84, 103, 111, 145 and 157 were positive, whereas all isolates (7–34 for each O group) of O groups 113, 132, and 153 and serotype O156:NM (38 isolates) were negative for eaeA. Seventy-three percent of 130 isolates of eaeA-positive serotypes produced VT1 only compared with 20% of 253 isolates of eaeA-negative serotypes. We conclude that there is a strong association between certain O groups and the eaeA gene, that serotypes of eaeA-positive and eaeA-negative VTEC implicated in human and cattle disease are present at high frequency in the faeces of healthy cattle, that VT1 is more frequently associated with eaeA-positive than with eaeA-negative serogroups, and that the eaeA gene is more frequently found in VTEC from calves compared with VTEC from adult cattle.

1. The strain HFEM of herpes simplex virus is highly virulent for the 5-week-old mouse when inoculated intracerebrally; the LD50 and the ID50 both being close to the egg infectious unit. It is also virulent when given intraspinally.

2. When inoculated peripherally it seldom causes nervous symptoms in the normal mouse but regularly does so if inoculated into skin which has previously been given a subcutaneous injection of 10% sodium chloride.

3. After intradermal inoculation of pretreated mice with strain HFEM, the paralysis is preceded by the appearance of infective virus in the blood, the sciatic nerve and the central nervous system. Invasion of the central nervous system is prevented by interruption of the local peripheral nerve.

4. There is no evidence that virus enters the central nervous system by way of the lymphatics or by direct extension through the tissues.

5. After intravenous inoculation virus does not invade the central nervous system unless (a) massive inocula are used or (b) the brain is traumatized by injecting sterile saline. After peripheral inoculation insufficient virus to infect even traumatized brain seems to circulate in the cerebral vessels. Paralysis and invasion of the central nervous system are not prevented by circulating neutralizing antibody given 18 hours after inoculation.

It therefore appears that invasion of the central nervous system takes place only by way of the peripheral nerve.

The distribution of inhaled bacterial aerosols has been studied in guinea-pigs, monkeys and mice, using Bacillus subtilis spores labelled with radiophosphorus. Particle sizes from about 1 to 12μ have been used.

The guinea-pig shows the expected change of distribution with particle size; the proportion retained in the head increases with increased particle size. The figures correspond closely with those for man. Monkeys show similar results but are more irregular.

The subsequent fate of the retained particles has been studied and accords with what is known about ciliary removal.

The work is intended to link with parallel investigations of respiratory infection in closely similar conditions, and its implications are discussed in a paper on that subject (Druett et al. 1953).

African swine fever virus (ASFV) continues to cause outbreaks in domestic pigs and wild boar in Eastern European countries. To gain insights into its transmission dynamics, we estimated the pig-to-pig basic reproduction number (R0) for the Georgia 2007/1 ASFV strain using a stochastic susceptible-exposed-infectious-recovered (SEIR) model with parameters estimated from transmission experiments. Models showed that R0 is 2·8 [95% confidence interval (CI) 1·3–4·8] within a pen and 1·4 (95% CI 0·6–2·4) between pens. The results furthermore suggest that ASFV genome detection in oronasal samples is an effective diagnostic tool for early detection of infection. This study provides quantitative information on transmission parameters for ASFV in domestic pigs, which are required to more effectively assess the potential impact of strategies for the control of between-farm epidemic spread in European countries.

Isolates from the intestinal Escherichia coli flora of 28 members of five families (including parents, children, and household pets) in Amherst, Massachusetts, and Rochester, New York, were characterized by the electrophoretic mobilities of 12 enzymes to estimate the extent of sharing of strains among associated and unassociated hosts. Among the 655 isolates examined, 60 different combinations of electromorphs (electrophoretic types or ETs), each representing a distinctive multilocus genotype, were identified, of which 85% were recovered from only a single individual. On average, 11 % of the ETs isolated from the same family were shared by two or more members; 4·9% of ETs were shared among members of unassociated families living in the same city; and only 2% were shared by families in different cities. All three ETs that were recovered from multiple hosts in the present study are widespread clones that have been isolated from many other host individuals in North America and Sweden.

Samples of blood, spleen and legs from 112 culled roe deer (Capreolus capreolus) were collected from nine sites widespread in the United Kingdom. The prevalence of infection with Ehrlichia phagocytophila was determined by serology and polymerase chain reaction. Means of 58% of 102 plasma or serum samples were seroreactive by IFA, 38% of 84 blood samples and 29% of 82 spleen samples were positive by PCR. Ticks on legs of 71 roe deer were Ixodes ricinus larvae, nymphs and adults and 83% of legs were infested. Numbers of ticks corresponded positively to the percentage of samples positive for E. phagocytophila by serology and PCR for different sampling sites. Ixodes ricinus nymphs collected from the vegetation at one site with infected deer were analysed for infection with E. phagocytophila by examination of Feulgen stained salivary glands. Of 135 nymphs 5% were infected. These results confirm that roe deer are commonly parasitized by both E. phagocytophila and its vector tick in such a way that it is likely to be an important natural mammalian reservoir of E. phagocytophila.

An outbreak of waterborne cryptosporidiosis affecting 27 persons, diagnosed stool positive, occurred in Ayrshire in April 1988. Twenty-one of the 27 confirmed cases required some form of fluid replacement therapy. Local general practitioners indicated a two- to fivefold increase in diarrhoeal disease during the outbreak, and following enquiries made by Environmental Health Officers it became apparent that many hundreds of people had suffered a diarrhoeal illness at that time. Cryptosporidium spp. oocysts were detected in the treated chlorinated water supply system, in the absence of faecal bacterial indicators. Oocyst contamination of a break-pressure tank containing final water for distribution was the cause of this waterborne outbreak. An irregular seepage of oocyst-containing water, which increased during heavy rains, was the cause of the break-pressure tank contamination, rather than a failure of the water-treatment processes. The waterborne route should be considered when clusters of cryptosporidiosis associated with potable water occur. Waterborne cryptosporidiosis can occur in the absence of other faecal indicators of contamination.

The prevalence of Clostridium botulinum type E gene in fish and fishery products of commercial importance in Finland was determined using a quantitative PCR analysis. The contamination level in 438 raw fish samples from intestines, surface and whole fish and 208 fish roe samples varied from 10–40% and from 4–14% respectively, depending on the fish species studied. The presence of C. botulinum in European wild freshwater fish and roe was demonstrated for the first time by isolation of the organism from PCR-positive samples. Five percent of 214 vacuum-packed and 3% of 123 air-packed fishery product samples examined at retail level were positive for the botulinum neurotoxin type E gene. A contamination level of 10% in vacuum-packed hot-smoked whitefish was detected. The results demonstrate that C. botulinum type E poses a serious health risk for those consuming fishery products from the Baltic Sea area.

Cowpox is an orthopoxvirus infection endemic in European wild rodents, but with a wide host range including human beings. In this longitudinal study we examined cowpox in two wild rodent species, bank voles Clethrionomys glareolus and wood mice Apodemus sylvaticus, to investigate the dynamics of a virus in its wild reservoir host. Trapping was carried out at 4-weekly intervals over 3 years and each animal caught was uniquely identified, blood sampled and tested for antibodies to cowpox. Antibody prevalence was higher in bank voles than in wood mice and seroconversion varied seasonally, with peaks in autumn. Infection was most common in males of both species but no clear association with age was demonstrated. This study provides a model for studying other zoonotic infections that derive from wild mammals since other approaches, such as one-off samples, will fail to detect the variation in infection and thus, risk to human health, demonstrated here.

The model was based on grasping a fabric-covered bottle contaminated with a strain of Staphylococcus saprophyticus, then grasping a sterile fabric-covered bottle and counting the organisms transferred. When the donor fabric was moist 10% of the available cells passed onto the hands, but this fell to 0·05% when the inoculum dried. Transfer from wet hands to the fabric amounted to 85%, but in the complete model only 0·06% of the available cells were transferred. The model was used to assess simple methods of degerming the hands. Washing the hands reduced transfer by 95%, while washing in 70% alcohol reduced transfer by 99·99%. Lesser procedures investigated included applying 0·2 ml of 80% ethanol to the hands, which reduced transfer by 93%.

Effective primary prevention of congenital toxoplasmosis requires up to date information on locally relevant risk factors for infection in pregnant women. In Naples, risk factors for toxoplasma infection were compared in recently infected women (as assessed by detection of specific IgM in serum) and susceptible, IgG negative women. Recent infection was strongly associated with frequency of consumption of cured pork and raw meat. Eating cured pork or raw meat at least once a month increased the risk of toxoplasma infection threefold.

This simple study design for determining locally relevant sources of toxoplasma infection is the first report of cured pork as a risk factor for infection. Further research is required to determine cyst viability in cured pork products. Our findings suggest that in southern Italy, cured pork and raw meat should be avoided by susceptible pregnant women.

Mathematical models of transmission dynamics of infectious diseases provide a useful tool for investigating the impact of community based control measures. Previously, we used a dynamic (constant force-of-infection) model for lymphatic filariasis to describe observed patterns of infection and disease in endemic communities. In this paper, we expand the model to examine the effects of control options against filariasis by incorporating the impact of age structure of the human community and by addressing explicitly the dynamics of parasite transmission from and to the vector population. This model is tested using data for Wuchereria bancrofti transmitted by Culex quinquefasciatus in Pondicherry, South India. The results show that chemotherapy has a larger short-term impact than vector control but that the effects of vector control can last beyond the treatment period. In addition we compare rates of recrudescence for drugs with different macrofilaricidal effects.

An outbreak of febrile gastroenteritis affected consumers of on-farm manufactured dairy products from a summer farm in Sweden. Symptoms included diarrhoea, fever, stomach cramps and vomiting in 88, 60, 54 and 21% of cases identified. The median incubation period was 31 h. A cohort study with 33 consumers showed an attack rate of 52% and an association between the total amount of product eaten and illness (P=0·07). Twenty-seven of 32 (84%) stool samples cultured for Listeria monocytogenes tested positive, although there was no association between clinical disease and the isolation of L. monocytogenes. In addition, gene sequences for VTEC and ETEC were detected in 6 and 1 subjects, respectively. Bacteriological analysis of cheese samples revealed heavy contamination with L. monocytogenes and coagulase positive staphylococci in all of them and gene markers for VTEC in one of them. Molecular profiles for L. monocytogenes isolated from dairy products, stool samples and an abscess from 1 patient who developed septic arthritis were identical. Results of both microbiological and epidemiological analyses point to L. monocytogenes as the most likely cause of this outbreak. The finding of markers for VTEC in some humans and cheese samples means that a mixed aetiology at least in some cases cannot be conclusively ruled out.

We compared gastroenteritis cases that consulted a general practitioner (GP) with those who did not in a community-based study and also with those in a GP-based study. We aimed to identify factors associated with consultation, and with inclusion of cases by GPs, and secondly to study the effects on the frequency of detection of pathogens. Furthermore, we estimated the under-ascertainment by GPs. Both studies were performed in The Netherlands in the same population in an overlapping time-period. Overall, 5% of community cases consulted a GP. Cases who consulted suffered from more severe episodes than non-consulting cases. Inclusion of cases by GPs, instead of a study team, caused a selection of more severe cases with more chronic symptoms. When extrapolating data from GP-based studies, it should be taken into account that, in general practice, gastroenteritis due to bacteria and Giardia lamblia is a relatively large proportion of that in the community and gastroenteritis due to Norwalk-like viruses is a relatively small proportion. The incidence of gastroenteritis in general practices was estimated between 14 and 35 per 1000 person years.