Feeding tests were carried out in the laboratory to evaluate WBA 8119 as a potential new rodenticide against wild common rats (Rattus norvegicus), ship rats (R. rattus) and house mice (Mus musculus). The results obtained are compared with data previously obtained for difenacoum, another member of the same series of 4-hydroxycoumarin anticoagulants.

With warfarin-resistant and non-resistant common rats, complete kills were obtained using a concentration of 0·0005% for 2 days, or 0·001 % for 1 day: a 1-day test at 0·0005% killed 6 out of 10 and 17 out of 20 of the two types respectively. At 0·005% complete kills of resistant ship rats were obtained after 2 days exposure and of resistant house mice after 1 day, but at 0·002% for 2 days there was some survival. Non-resistant ship rats and house mice were all killed after 2 days feeding on 0·002% bait.

In 2-day palatability tests, R. norvegicus showed no significant aversion to the poison at 0·002% and 100% mortality was obtained. The poison was significantly unpalatable to R. rattus at 0·005% and to M. musculus at 0·005% and 0·002 %, although with the last species these concentrations gave complete kills.

It is concluded that WBA 8119 has greater activity than other known anticoagulants against the three commensal species examined. The laboratory results suggest that concentrations between 0·0005% and 0·002% would be suitable for field use against common rats, and between 0·002% and 0·005% for ship rats and house mice.

An ordinary differential equation model was developed to simulate dynamics of Staphylococcus aureus mastitis. Data to estimate model parameters were obtained from an 18-month observational study in three commercial dairy herds. A deterministic simulation model was constructed to estimate values of the basic (R0) and effective (Rt) reproductive number in each herd, and to examine the effect of management on mastitis control. In all herds R0 was below the threshold value 1, indicating control of contagious transmission. Rt was higher than R0 because recovered individuals were more susceptible to infection than individuals without prior infection history. Disease dynamics in two herds were well described by the model. Treatment of subclinical mastitis and prevention of influx of infected individuals contributed to decrease of S. aureus prevalence. For one herd, the model failed to mimic field observations. Explanations for the discrepancy are given in a discussion of current knowledge and model assumptions.

Sheep infected with FMDV strains of different epizootiological origin developed a carrier state which persisted in the majority of animals for 1–5 months.

The sites of virus persistence and multiplication in the convalescent animal were identified by titration of suspensions of mucosae and epithelia taken post mortem. Virus was recovered most frequently and in highest titre from the tonsillar area and less frequently from the pharynx and dorsal surface of the soft palate. No virus was found in samples taken from the nasal passages, the trachea or the rumen.

A multiethnic cohort of adult members of the Kaiser Permanente Medical Care Program (55300 men and 65271 women) was followed for 15 years (1979–93) to assess the association between total cholesterol and risk of infections (other than respiratory and HIV) diagnosed in the in-patient setting. Using multivariate Cox regression, total cholesterol was inversely and significantly related to urinary tract, venereal, musculo-skeletal, and all infections among men; and to urinary tract, all genito-urinary, septicaemia or bacteraemia, miscellaneous viral site unspecified, and all infections among women. The reduction of risk of all infections associated with a 1 s.d. increase in total cholesterol was 8% in both men (95% CI, 4–12%) and women (95% CI, 5–11%). For urinary tract infections among men, as for septicaemia or bacteraemia and nervous system infections among women, the risk relation was restricted to persons aged 55–89 years. Nervous system infections were positively related to total cholesterol among women aged 25–54. In both genders, the significant inverse association with all infections persisted after excluding the first 5 years of follow-up. Collectively, these data are suggestive of an inverse association, although not entirely consistent, between total cholesterol and incidence of infections either requiring hospitalization or acquired in the hospital. Further research is needed to elucidate whether these associations are biologically plausible or represent uncontrolled confounding by unmeasured risk factors.

Vaccination can be a useful tool for the control of avian influenza (AI) outbreaks, but its use is prohibited in most of the countries worldwide because of its interference with AI surveillance tests and its negative impact on poultry trade. AI vaccines currently in use in the field increase host resistance to the disease but have a limited impact on the virus transmission. To control or eradicate the disease, a carefully conceived vaccination strategy must be accompanied by strict biosecurity measures. Some countries have authorized vaccination under special circumstances with contradictory results, from control and disease eradication (Italy) to endemicity and antigenic drift of the viral strain (Mexico). Extensive vaccination programmes are ongoing in South East Asia to control the H5N1 epidemic. This review provides practical information on the available AI vaccines and associated diagnostic tests, the vaccination strategies applied in Asia and their impact on the disease epidemiology.

Oral administration of strains of food poisoning salmonellas to day-old chickens produced a profound inhibition in the subsequent colonization of the caeca by a strain of Salmonella typhimurium given one day later. Closely related genera were unable to produce a similar inhibition. The inhibition was not the result of bacteriophages produced by the first strain. Neither was it the result of an immunological response by the host induced by the first strain. In additional experiments in day-old chickens, inhibition of an Escherichia coli Nalr strain and of a Citrobacter sp. Nalr strain was produced by the antibiotic-sensitive forms of the homologous strains while strains from other genera did not produce any inhibition. When an avirulent mutant of S. typhimurium was used for pre-treatment a statistically significant reduction in the excretion of the super-infecting S. typhimurium Nalr strain over several weeks was produced. A genus specific inhibition was reproduced in vitro by mixed culture experiments. Live cultures were necessary for in vitro inhibition. Killed cells or a culture supernatant produced no inhibition.

Meningococcal serogroup W strains have been emerging throughout the current century with most of the isolates belonging to the sequence type (ST11)/electrophoretic type (ET37) clonal complex (ST11/E37 CC), particularly since the international outbreak following Hajj 2000. That outbreak appears to have triggered off that trend, contributing to the spread of W ST11/ET37 CC strains globally; however, local strains could be also responsible for increases in the percentage and/or incidence rates of this serogroup in some countries. More recently, unexpected increases in the percentage and incidence rate of W has been noticed in different countries located in the South Cone in Latin America, and W ST11/ET37 CC strains now appear as endemic in the region and an extensive immunization programme with tetravalent conjugate vaccine (covering serogroups A, C, Y and W) has been recently implemented in Chile. It is difficult to ascertain whether we are observing the emergence of W ST11 CC strains in different geographical areas or whether the Hajj 2000 strain is still spreading globally. Several aspects of the evolution of that situation are analysed in this paper, reviewing also the implications in immunization programmes. Closely related with the analysis of this potential evolution, it will be very interesting to monitor the evolution of serogroup W in the African meningitis belt after implementation of the extensive immunization programme with serogroup A conjugate vaccine that is currently underway. More data about carriers, transmission, clonal lineages, etc. are needed for taking decisions (target groups, outbreak control, defining the extent, etc.) to adapt the response strategy with potential interventions with broad coverage vaccines against the emergent serogroup W.

Eight cases of Salmonella senftenberg infection in infants were identified in the first half of 1995 in England, five were indistinguishable S. senftenberg strains. A case-control study showed an association between illness and consumption of one brand of baby cereal (P=0·03). The cereal manufacturer reported isolating S. senftenberg in June 1994 from an undistributed cereal batch. Outbreak strains and the cereal strain were all plasmid-free in contrast to other human isolates of S. senftenberg in the same period. Changes in the production process were implemented to prevent further contamination.

Surveillance centres should strengthen the detection and investigation of outbreaks of gastrointestinal infection in susceptible groups, especially young children. In this outbreak, the study of only five cases led to identification of the vehicle of infection. Even when few cases are reported, epidemiological investigation in conjunction with molecular typing may lead to public health action which prevents continuing or future outbreaks.

Considerable and reproducible differences were observed in the amount and duration of faecal excretion when in-bred lines of chickens were infected orally with S. enterica serovar Typhimurium at 6 weeks of age after being given a gut flora preparation when newly hatched. Similar but less pronounced results were observed with S. Enteritidis or S. Infantis. Differences in the viable numbers of the inoculated bacteria in caecal contents were detectable within 24 h of inoculation. No major differences were seen in Salmonella-specific serum IgA or IgG titres. Small differences were seen in the numbers of circulating heterophilic cells. Caecal contents taken from the more resistant lines immediately prior to challenge appeared to be no more inhibitory for Salmonella in vivo than contents taken from susceptible lines. The more resistant lines showed a slightly higher rate of intestinal flow, as indicated by the rate of production of faecal droppings, although there was no difference in the rate of emptying of the caeca. In an F1 generation resistance was dominant and not sex-linked. There was no MHC linkage or any association with SAL1, the gene implicated in resistance to systemic salmonellosis in chickens, or NRAMP1.

A survey of Campylobacter species in the faeces or rectal contents of domestic animals was carried out using direct and enrichment culture methods. Campylobacters were isolated from 259 (31 %) of 846 faecal specimens. The highest isolation rate was found in pigs (66%); lower rates were found in cattle (24%) and sheep (22%). In pigs all the isolates were C. coli, in sheep and cattle about 75% were C. jejuni. Only five isolations of C. fetus suhsip. fetus were made, all from cattle. More pigs with diarrhoea had C. coli in their faeces than healthy pigs (77% vs 47 %), but such a clear difference in isolation rate between sick and healthy animals was not seen in cattle or sheep.

The enrichment method increased the total isolation rate of C. jejuni and C. coli by 33%, but for cattle specimens it increased it by 69% (from 6·5% to 21%). However, the enrichment method failed to detect 16% of positive specimens (mainly C. coli), so direct and enrichment methods should be used for the culture of campylobacters from animal faeces. The results show that cattle, sheep and pigs constitute a large potential source of campylobacter infection for man.

The Netherlands experienced an unprecedented outbreak of Q fever between 2007 and 2010. The Jeroen Bosch Hospital (JBH) in 's-Hertogenbosch is located in the centre of the epidemic area. Based on Q fever screening programmes, seroprevalence of IgG phase II antibodies to Coxiella burnetii in the JBH catchment area was 10·7% [785 tested, 84 seropositive, 95% confidence interval (CI) 8·5–12·9]. Seroprevalence appeared not to be influenced by age, gender or area of residence. Extrapolating these data, an estimated 40 600 persons (95% CI 32 200–48 900) in the JBH catchment area have been infected by C. burnetii and are, therefore, potentially at risk for chronic Q fever. This figure by far exceeds the nationwide number of notified symptomatic acute Q fever patients and illustrates the magnitude of the Dutch Q fever outbreak. Clinicians in epidemic Q fever areas should be alert for chronic Q fever, even if no acute Q fever is reported.

The aim of this study was to analyse the spatio-temporal dynamics of Toxoplasma gondii infection in long-term monitoring of domestic cats (8–15 years) in three populations living in rural France. Overall seroprevalence was 52·7% (modified agglutination test ⩾1:40). Incidence was 0·26–0·39 seroconversions/cat per year, and the estimated rate of soil contamination by T. gondii oocysts ranged between 31 and 3600 oocysts/m2 per year, depending on the population. Incidence risk in cats was related to mean precipitation, explaining both the spatial and temporal variability in risk: local conditions explained differences between the three study sites and incidence risk increased during rainy years. This study brings rare quantitative information on the level of contamination of the environment by T. gondii oocysts, and suggests that the spatio-temporal distribution of incidence risk in cats may reflect both the influence of rain on prey populations and infectivity of T. gondii oocysts.

We analysed data on laboratory or epidemiologically confirmed cases (n = 856 539) and on outbreaks (n = 31 644) notified during week 31 (2001) to week 30 (2009), and performed molecular typing of specimens from 665 outbreaks. We aimed at identifying demographic and molecular characteristics to inform on potential additional approaches to prevent disease spread in the population. The mean incidence by norovirus season (week 31 in one year to week 30 in the following year) was 130 (range 19–300) cases/100 000 population and was highest in persons aged <5 years (430/100 000) and ⩾75 years (593/100 000). The proportion hospitalized in community-acquired cases was 8–19% per season. The mean norovirus-associated mortality was 0·05/100 000 per season and 0·5/100 000 in the ⩾75 years age group. Most outbreaks with known setting (75%) occurred in hospitals (32%), nursing homes (28%), households (24%) and childcare facilities (10%). GII strains dominated in the outbreak specimens. GII.4 strains were found in 82% of nursing home outbreaks, 85% of hospital outbreaks, and 33% of childcare facility and school outbreaks. Cases in younger individuals were notified earlier during the season than adult cases, and outbreaks in childcare facilities and schools preceded those in nursing/residential homes, hospitals and private households. We suggest future studies to investigate more closely potential transmission patterns between children and adults.

Acute diarrhoea remains a major public health challenge in developing countries. We examined the role of a probiotic in the prevention of acute diarrhoea to discover if there was an effect directed towards a specific aetiology. A double-blind, randomized, controlled field trial involving 3758 children aged 1–5 years was conducted in an urban slum community in Kolkata, India. Participants were given either a probiotic drink containing Lactobacillus casei strain Shirota or a nutrient drink daily for 12 weeks. They were followed up for another 12 weeks. The primary outcome of this study was the occurrence of first episodes of diarrhoea. We assessed this during 12 weeks of intake of study agent and also for 12 weeks of follow-up. There were 608 subjects with diarrhoea in the probiotic group and 674 subjects in the nutrient group during the study period of 24 weeks. The level of protective efficacy for the probiotic was 14% (95% confidence interval 4–23, P<0·01 in adjusted model). The reduced occurrence of acute diarrhoea in the probiotic group compared to nutrient group was not associated with any specific aetiology. No adverse event was observed in children of either probiotic or nutrient groups. The study suggests that daily intake of a probiotic drink can play a role in prevention of acute diarrhoea in young children in a community setting of a developing country.

An antiglobulin enzyme-linked immunosorbent assay for rubella-specific IgG1 and IgG3 was adapted to measure antibody avidity by incorporating a mild protein denaturant, diethylamine (DEA), into the serum diluent. Sera were tested at varying dilutions, both with and without DEA, if they contained sufficient specific IgG1 or IgG3. The optical density (OD) was measured and curves were plotted. The highest OD (V) was noted and halved (V/2). The distance between the OD curves at V/2 was measured as the DEA shift value.

Sera were examined from people whose sera contained rubella-specific antibodies as a consequence of infection or vaccination in the distant past (24 sera), recent primary rubella (66 sera), symptomatic reinfection (11 sera) or asymptomatic reinfection (64 sera). For specific IgG1 the DEA shift value was <O·6 for cases of rubella in the distant past, compared with >0·8 for the first month after primary infection. The maximum DEA shift value for the sera from cases of reinfection was 0·65.

No serum from cases of rubella in the distant past contained sufficient specific IgG3 to estimate avidity. The sera collected within 1 month of onset of primary rubella gave DEA shift values >O·7 compared with sera from reinfections, which gave DEA shift values <O·6, except for two sera from a case of symptomatic reinfection.

Thus the assessment of specific IgG subclass avidity is of value in differentiating serologically primary rubella from reinfection.

Effective infection control measures during norovirus outbreaks are urgently needed in places where vulnerable individuals gather. In the present study, the effect of a number of measures was investigated in daily practice. Forty-nine Dutch nursing homes were monitored prospectively for norovirus outbreaks during two winter seasons. A total of 37 norovirus outbreaks were registered. Control measures were most effective when implemented within 3 days after onset of disease of the first patient. Measures targeted at reduced transmission between persons, via aerosols, and via contaminated surfaces reduced illness in staff and in residents. Reducing illness in staff results in fewer costs for sick leave and substitution of staff and less disruption in the care of residents. The effect of control measures on outbreak duration was limited. This is the first intervention study examining the effect of control measures. Further research is needed to extend and refine the conclusions.

We evaluated whether the increased immunogenicity provided by an MF59-adjuvant influenza vaccine translates into increased protection among the elderly. Residents of 25 long-term care facilities received either the adjuvant or a non-adjuvant vaccine. The odds ratios (OR) of influenza-like illness were calculated for non-adjuvant vs. adjuvant vaccine recipients, also stratifying for chronic cardiovascular, respiratory, and renal diseases. The risk was higher for the non-adjuvant vaccine recipients and highest for those with respiratory disease (OR 2·27, 95% CI 1·09–4·82) and cardiovascular disease (OR 1·88; 95% CI 1·31–2·72). In this study the MF59-adjuvant vaccine provided superior clinical protection among the elderly, especially those with chronic diseases.

The 2013 multistate outbreaks contributed to the largest annual number of reported US cases of cyclosporiasis since 1997. In this paper we focus on investigations in Texas. We defined an outbreak-associated case as laboratory-confirmed cyclosporiasis in a person with illness onset between 1 June and 31 August 2013, with no history of international travel in the previous 14 days. Epidemiological, environmental, and traceback investigations were conducted. Of the 631 cases reported in the multistate outbreaks, Texas reported the greatest number of cases, 270 (43%). More than 70 clusters were identified in Texas, four of which were further investigated. One restaurant-associated cluster of 25 case-patients was selected for a case-control study. Consumption of cilantro was most strongly associated with illness on meal date-matched analysis (matched odds ratio 19·8, 95% confidence interval 4·0–∞). All case-patients in the other three clusters investigated also ate cilantro. Traceback investigations converged on three suppliers in Puebla, Mexico. Cilantro was the vehicle of infection in the four clusters investigated; the temporal association of these clusters with the large overall increase in cyclosporiasis cases in Texas suggests cilantro was the vehicle of infection for many other cases. However, the paucity of epidemiological and traceback information does not allow for a conclusive determination; moreover, molecular epidemiological tools for cyclosporiasis that could provide more definitive linkage between case clusters are needed.

The sheep and goat pox viruses isolated in Kenya are not host specific as in the Middle East and India. The virus strains from one species are of a similar patho-genicity for the other, and the same virus appears to occur in field outbreaks in mixed flocks. A silent infection with no skin lesions occurs in the field outbreaks.

The virus grows well in lamb testis cell cultures, it does not haemadsorb nor haemagglutinate and is ether sensitive. Most strains could not readily be adapted to grow on the chorioallantoic membrane of embryonated eggs; one isolation only was made in this way. Staining of the virus inclusions showed that they were of DNA; the virus resembled that of lumpy skin disease in many characteristics.

It was possible to cross-protect both species with virus of sheep or goat origin. A vaccine was made from tissue culture virus adsorped onto aluminium hydroxide gel and treated with formalin.

Results of a surveillance on cholera conducted with patients seen at the Children Hospital in Bangkok, Thailand from August 1993 to July 1995 are presented. Annually, isolation rates for Vibrio cholerae varied between 1·7 and 4·4% of patients with diarrhoea. V. cholerae O1 serotype Ogawa accounted for between 31 and 47% of patients cultured positive for V. cholerae, whereas the O139 serotype dominated in early 1994 after which it disappeared. Non-O1, non-O139 strains were isolated at similar rates as serotype O1 in 1993 and 1994, but accounted for 69% of V. cholerae culture positive specimens in 1995. However, the annual proportion of the isolation of non-O1, non-O139 strains showed little variation and remained low between 1·0 and 1·3%. Serotyping of 69 epidemiological unrelated non-O1, non-O139 strains produced 37 different O-serotypes. BglI ribotyping of serotypes containing more than two strains demonstrated a high degree of heterogeneity within and between serotypes, except seven serotype O37 strains which showed an identical ribotype suggesting clonality. None of the 69 strains hybridized with a cholera toxin probe and only two strains hybridized with a heat-stable enterotoxin probe. Susceptibility testing to 12 antibiotics showed that 40 of 69 (58%) non-O1, non-O139 strains were resistant to colistin, streptomycin and sulphisoxazole and 28 of 69 (41%) were multiple antibiotic resistant (MAR; [ges ]4 antibiotics). Although 26 of 69 (38%) strains contained one or more plasmids, the plasmids were of low molecular weights and did not seem to encode antibiotic resistance. The results of the present study showed that a high proportion of heterogenous MAR V. cholerae non-O1, non-O139 strains were isolated from children at the hospital. With reference to the emergence of V. cholerae O139 in 1992, we suggest that non-O1, non-O139 strains should be monitored carefully to detect new serotypes with a possible epidemic potential, but also to determine the development and mechanism of antibiotic resistance.