HIV and HTLV seroprevalence was determined by means of unlinked anonymous testing of 2144 sera, originally obtained from primary care patients by representative sampling of the Spanish population aged 15-39 years in 1996. HIV-1 seroprevalence was 4·3 per 1000 population in the 15–39 years age group [95% confidence interval (CI), 1·5–10·7] and 5·6 per 1000 (95% CI, 1·8–15·3) in the 20–39 years age group. Seroprevalence proved higher in males and urban residents. No antibodies to HIV-2 and HTLV-I were detected in any of the sera studied. However, presence of antibodies to HTLV-II was confirmed in one serum sample, while HTLV seroreactivity, though detected in another, could not be typed. The two HTLV-positive results equated to a seroprevalence of 1·9 per 1000 in the 20–39 years age group (95% CI, 0·3–8·6). HIV-1 seroprevalence was consistent with previous estimates yielded by back-calculation. The level of HTLV seroprevalence found suggests endemicity.

Nasopharyngeal secretions were taken during the acute phase of illness from 66 infants and children admitted to hospital with lower respiratory tract infections. Second secretions were taken, after an interval of 7 days, from 33 of these patients. A significant increase in neutralizing activity to R.S. virus was demonstrated in the nasopharyngeal secretions of patients in response to severe R.S. virus infection. Seventeen out of 25 patients (68%) with R.S. virus infections developed a rise in secretory neutralizing titre, compared with only 1 out of 8 patients (13%) with respiratory infections not involving R.S. virus.

A high titre of secretory neutralizing activity was found more often in the acute phase of illness in patients with R.S. virus infections, especially bronchiolitis, than in patients with respiratory infections not involving R.S. virus. Fifteen out of 34 patients (44%) with R.S. virus bronchiolitis were found to possess a neutralizing titre of 1/4 or more in their first secretions, compared with 4 out of 12 patients (33%) with R.S. virus infections other than bronchiolitis and 3 out of 20 patients (15%) with respiratory infections not involving R.S. virus.

A quantitative analysis of the immunoglobulins present in the secretions indicated that IgA was the only immunoglobulin consistently present at a detectable concentration. The geometric mean values of IgA, IgM and IgG in the secretions examined were found to be 22·3, 4·3 and 5·3 mg./lOO ml. respectively.

The neutralizing activity against R.S. virus, present in the secretions, was shown to be due to specific IgA antibody. This was accomplished by removing the neutralizing activitv in two secretions bv absorotion with anti-IaA serum.

Commercially reared chickens were challenged with Salmonella enteritidis phage-type (PT) 4 by aerosol, or via the conjunctiva. Inhalation of 2·9 × 102 or 4·2 × 103 S. enteritidis resulted in the production of IgG antibodies to the lipopolysaccharide (LPS) of S. enteritidis PT4. When the aerosol inoculum was increased to 2·4 × 105 bacteria per bird the antibody produced were predominantly of the IgM-class. Chickens challenged with 103S. enteritidis PT4 via the conjunctiva mounted only a poor immune response. Increasing the challenge dose to 108 S. enteritidis resulted in the production of high-titre serum antibodies of both the IgG and IgM classes. Results from this study suggest that aerosols containing small numbers of S. enteritidis PT4 might be responsible for intraflock infection of poultry.

It has not yet been possible to breed hedgehogs in laboratory cages, but they have been bred and reared successfully in pens in the open, twenty-seven young being produced by five females in seven litters. The methods adopted in breeding and maintaining this stock are described.

Although social networks are known to play an important role in drug-using behaviours associated with hepatitis C virus (HCV) infection, literature on social networks and HCV is inconsistent. This exploratory study examined HCV RNA distribution within a social network of anti-HCV-positive non-medical prescription opioid users (NMPOUs) in rural Appalachia. Participants were tested serologically for HCV RNA, and behavioural, demographic, and network data were collected using interview-administered questionnaires. Multivariate analyses were performed using logistic regression. Behavioural and demographic characteristics did not differ by RNA status. In the multivariate model, recent injecting drug users (IDUs) were more likely to be RNA positive [odds ratio (OR) 4·06, 95% confidence interval (CI) 1·04–15·83], and turnover into an IDU's drug network was significantly protective (OR 0·15, 95% CI 0·03–0·75). This is the first study to date to examine HCV distribution in rural NMPOUs from a network perspective and demonstrates that network characteristics significantly contribute to the epidemiology of HCV in this understudied, high-risk population.

Six hundred and twenty-four Vibrio cholerae O1 strains, 623 serotype Ogawa and one serotype Inaba, isolated in Romania between 1977–95 were tested to detect all changing traits concerning serogroup, serotype, biotype, phage type and resistotype patterns and subsequently, the possible epidemiological relationship among these strains. Biotyping revealed one classical, 580 eltor strains and 43 intermediary variants. When tested with Mukerjee phages, 546 (87%) strains were sensitive and 78 (13%) resistant. One phage type (M4) dominated during 1977–90, two phage types (M4 and M5) exhibited the same high frequencies during 1991, a diversity of types occurred during 1993–4 whereas in 1995, two phage types (M4 and M5) showed similar distributions again. Five patterns of drug susceptibility were successively described during 1977–95. The most prominent changes in Vibrio cholerae O1 strains were noticed during 1993–4: the highest number of non-typable strains and intermediary variants, the widest spectrum of phage types and of multidrug resistance. In 1995, the strains reverted to the previous typable forms but a new drug resistance pattern was noticed.

The complement-fixing antigen activity of canine hepatitis virus is due to particles which are estimated to measure from 70 to 105 mμ and which probably can form larger aggregates. The active particles in the original virus tissue suspension were of sizes similar to those in the purified preparations, their serological properties being identical. The chemical properties of the antigen are those of protein, probably ribonucleoprotein. No evidence has been obtained to explain the association of a high concentration of the antigen with the presence of numerous intranuclear inclusion bodies in the lesions. It is evident, however, from these experiments that the inclusion bodies are not just deposits of the serologically active material. Since the intranuclear inclusion bodies and also the antigen are probably composed of ribonucleoprotein, it is possible that they both represent certain stages in the formation of virus protein by a catalytic reaction from the denatured host proteinogen.

In summer 2008, we investigated an outbreak of diarrhoeal illness in participants of a mountain-bike event in Wales (UK) which had been affected by heavy rain. We conducted a retrospective cohort study to investigate the cause using an internet-based questionnaire. Fifty-three percent of those contacted responded, and 161 (46·5%) out of the 347 responders, reported gastrointestinal symptoms. Median day of onset was 3 days following the event. Ten riders reported receiving a laboratory-confirmed diagnosis of Campylobacter. Multivariate logistic regression analysis identified the inadvertent ingestion of mud (OR 2·5, 95% CI 1·5–4·2, P<0·001) and eating ‘other’ food during the event (OR 2·1, 95% CI 1·2–3·6, P=0·01) as significant risk factors for illness. We concluded that the outbreak was caused by Campylobacter, spread to the riders by the inadvertent ingestion of mud which had been contaminated with sheep faeces from the rural course. Mountain-bike race organizers should consider microbiological hazards when risk-assessing potential race courses. The internet is an efficient tool for the investigation of outbreaks in computer-literate populations.

During a period of five years 1192 water samples from swimming pools were examined for staphylococci and 338 for coliform organisms only. Eighty-nine different pools were sampled.

Numbers of staphylococci, estimated by the membrane filtration technique did not bear any significant relation to either bathing load or concentration of free chlorine.

Wide variation in the staphylococcal count was observed when different parts of a pool were sampled on the same occasion.

The only practicable standard for pool samples in relation to staphylococci would appear to be that these organisms should be absent from 100 ml. water when the pool has been out of use during at least ten hours before sampling if filtration and chlorination are adequate.

Small rodents were collected live in two different locations within a nephropathia epidemica (NE) endemic area, and tested for both antiviral serum antibodies and viral antigens in lung sections. In one location, only Apodemus sylvaticus (woodmice) were found in the traps, in the other, both A. sylvaticus and Clethrionomys glareolus (bank voles) were collected.

Among the woodmice from the former location the prevalence of NE virus markers was significantly lower than for either woodmice or bank voles from the other location, and no NE antigen-positive animals was found. The woodmice co-existing with bank voles had a lower prevalence of NE antigen and antibodies than the bank voles, and fewer woodmice had both antibodies and antigen. The results emphasize the important role of bank voles as a major NE virus reservoir and probable source of human infections.

The aim of this study was to investigate the relationship between dog and cat ownership and gastroenteritis in young children. A diary study of 965 children aged 4–6 years living in rural or semi-rural South Australia was undertaken. Data were collected on pet ownership, drinking water and other risk factors for gastroenteritis. Overall 89% of households had pets and dog ownership was more common than cat ownership. The multivariable models for gastroenteritis and pet ownership indicated that living in a household with a dog or cat was associated with a reduced risk of gastroenteritis (adj. OR 0·71, 95% CI 0·55–0·92; OR 0·70, % CI 0·51–0·97 respectively). This paper adds to the evidence that pets are not a major source of gastroenteritis in the home and lends support to the health benefits of pet ownership. However, this must be weighed against the potential negative consequences, such as dog bites, particularly for this age group.

The study's objectives were to investigate the prevalence, incidence, persistence, and associated risk factors of syphilis in female sex workers (FSWs) in Kaiyuan City, Yunnan, China. Three serial cross-sectional surveys were conducted and biological specimens were collected and tested for HIV, sexually transmitted infections, and drug use. The logistic Generalized Estimating Equation regression model was used to identify risk factors for prevalent syphilis. The prevalence of syphilis was 7·5%, 8·4% and 8·8%, respectively, in the three survey periods. Estimated syphilis incidence was 1·07 cases/100 person-years, and the persistence of syphilis per person at 6 months was 90·4%. In multivariate analysis, the factors associated with syphilis were age, lower education level, number of clients in a week, inconsistent condom use with clients, herpes simplex virus type 2 (HSV-2), and Chlamydia trachomatis. Persistent syphilis in this population of FSWs is a serious public health concern.

During a 6-month period an epidemiological survey of the carriage of Klebsiella was conducted in a hospital ward where no outbreak of nosocomial infection occurred. In this endemic situation the regular sampling of several sites on patients, members of the nursing staff, and the environment, and the biotyping of Klebsiella made it possible to analyse the patterns of transmission between sites. There was abundant evidence for striking transmission of Klebsiella between the throat, hands, and faeces of patients. Transmission between patients seemed to be mainly through hands. The role of nurses' hands in transmission was not evident from this survey, probably due to the relatively long interval (a week) between samplings. Through the hands of patients, wash stands and the surrounding floor were contaminated with Klebsiella. The biotyping of Klebsiella facilitated the epidemiological analysis of the results.

A time-series analysis was performed to identify the impact of bed occupancy rates and length of hospital stay on the incidence of Clostridium difficile infections (CDI). Between January 2003 and July 2008, a mean incidence of 0·5 CDI cases/1000 patient days was recorded. Application of a multivariate model (R2=0·50) showed that bed occupancy rates on general wards (P<0·01) and length of stay in intensive care units (ICUs) (P<0·01) influenced the incidence of CDI. Overcrowding on general wards and long periods in ICUs were identified as being positively associated with the incidence of CDI.

The incidence, morbidity, and mortality associated with Clostridium difficile gastrointestinal infections has increased greatly over recent years, reaching epidemic proportions; a trend due, in part, to the emergence of hypervirulent and antibiotic-resistant strains. The need to identify alternative, non-antibiotic, treatment strategies is therefore urgent. The ability of bacteria in faecal matter transplanted from healthy individuals to displace pathogen populations is well recognized. Further, there is growing evidence that such faecal microbiota transplantation can be of benefit in a wide range of conditions associated with gut dysbiosis. Recent technical advances have greatly increased our ability to understand the processes that underpin the beneficial changes in bacterial community composition, as well as to characterize their extent and duration. However, while much of the research into faecal microbiota transplantation focuses currently on achieving clinical efficacy, the potential for such therapies to contribute to the transmission of infective agents also requires careful consideration.

A method has been devised whereby the potency of any given carcinogenic agent can be compared with that of a standard agent. This is called the standard carcinogenic potency of the agent (P.). The relative potency of the agent (R.P.), calculated from P., permits one to estimate the effect on the agent of different chemical treatments, dilutions, etc., the percentage increase or decrease in activity of the agent being at once shown. A unit of carcino-genicity (U.C.) has been established, and a concentration of 500 carcinogenic units per cubic centimetre is considered to induce the maximum relative response on animals when the agent is applied twice a week. These standards have been devised as a natural sequence to the accumulation of a vast amount of experimental data the correlation of which necessitated some expedient more rapid and covering a wider field than the graphs formerly utilized.

One hundred and ninety-two strains of Neisseria gonorrhoeae isolated from migrant mine-workers were tested for their susceptibility to antibiotics, auxotyped and serotyped. Of the total, 93 (48%) were acquired locally and 64 (33%) from different geographical locations. Plasmid-mediated resistance to penicillin was found in 28 (14·6%) strains and was associated predominantly with the presence of 5·0 kb penicillinase encoding plasmid (18/28, 64%). Chromosomal resistance to penicillin (MIC ≥ 1 mg/l) was detected in 14 (7·3%) strains. Resistance to tetracycline was chromosomally and not plasmid-mediated. Antibiotic resistance was encountered most commonly among strains acquired in Natal. The overall gonococcal population was sensitive to ceftriaxone, ciprofloxacin. spectinomycin and azithromycin. Nine auxotype/serovar (A/S) classes were encountered among penicillinase-producing N. gonorrhoeae (PPNG) compared to 24 A/S classes among non-PPNG strains. The most common A/S class was NR/IA-6 which accounted for 38% of PPNG and 15% of non-PPNG.

Campylobacter spp. is a commonly reported food-borne disease with major consequences for morbidity. In conjunction with predicted increases in temperature, proliferation in the survival of microorganisms in hotter environments is expected. This is likely to lead, in turn, to an increase in contamination of food and water and a rise in numbers of cases of infectious gastroenteritis. This study assessed the relationship of Campylobacter spp. with temperature and heatwaves, in Adelaide, South Australia.

We estimated the effect of (i) maximum temperature and (ii) heatwaves on daily Campylobacter cases during the warm seasons (1 October to 31 March) from 1990 to 2012 using Poisson regression models.

There was no evidence of a substantive effect of maximum temperature per 1 °C rise (incidence rate ratio (IRR) 0·995, 95% confidence interval (95% CI) 0·993–0·997) nor heatwaves (IRR 0·906, 95% CI 0·800–1·026) on Campylobacter cases. In relation to heatwave intensity, which is the daily maximum temperature during a heatwave, notifications decreased by 19% within a temperature range of 39–40·9 °C (IRR 0·811, 95% CI 0·692–0·952). We found little evidence of an increase in risk and lack of association between Campylobacter cases and temperature or heatwaves in the warm seasons. Heatwave intensity may play a role in that notifications decreased with higher temperatures. Further examination of the role of behavioural and environmental factors in an effort to reduce the risk of increased Campylobacter cases is warranted.

The nasal carriage of 407 mothers before, during and after admission to a maternity hospital and that of their babies during and after hospital stay was investigated together with the nasal carriage by the hospital staff.

The nasal carrier rate among mothers admitted to hospital was 38%, 40% of these strains being resistant to penicillin.

The nasal carrier rate among the nursing staff was 38 and 72% of these were resistant to penicillin.

If a population is swabbed only once approximately 25% of the carriers will be missed. Those showing slight carriage were no more likely to be missed than those showing heavy carriage. The concentration of organisms in the nose is evidently varying continuously.

Heavy carriers are no more likely to transmit than light carriers and it is therefore not right to report on the profusion or otherwise of growth if that implies a greater chance of transmission.

The biggest increase in resistance among nursing staff strains occurred in the non-typable group which could be explained by resistance to phage developing concurrent with resistance to antibiotics.

The difference in phage-distribution between patient and staff strains centred in group II which formed 19% of patient strains but only 7% of hospital strains.

The carrier rate was no higher for those with a history of hospital admission within 12 months or without a history of staphylococcal sepsis.

Those giving a history of penicillin therapy had the same resistance rate as those without a history of such therapy.