This review examines the current situation of bovine tuberculosis (bTB) in southern African savannah systems, and uses theory on multi-species host–pathogen systems to suggest possible options for future research and management. In southern Africa, the buffalo (Syncerus caffer) and the Kafue lechwe [Marsh antelope] (Kobus leche) have been found to be maintenance hosts for this disease, but the importance of other host species is becoming apparent. The role of other host species in the maintenance and spread of the disease varies, depending on the spatial distribution and resource utilization patterns of the species, disease susceptibility, transmission modes and the ecology of both host(s) and vector(s). Future research needs to identify the pathogenicity of bTB in each of the host species, and the mechanisms and rates of inter- and intra-specific transmission among different species, in order to develop multi-host models to understand the development and spread of the disease.

An outbreak of gastroenteritis affected a school attended by children aged 4–11 years. Epidemiological features suggested this was due to Norwalk-like virus (NLV) and this was confirmed by polymerase chain reaction (PCR). Nucleotide sequence analysis of the PCR amplicons revealed identical strains in all five positive stool samples. Pupils were significantly more likely to become ill following an episode of vomiting within their classroom (adjusted odds ratio 4·1, 95% CI 1·8–9·3). The times from exposure to illness were consistent with direct infection from aerosolized viral particles where exposure to vomiting was high.

Cleaning with quaternary ammonium preparations made no impact on the course of the outbreak. However, the outbreak stopped after the school closed for 4 days and was cleaned using chlorine-based agents. This study confirms the importance of vomiting in the transmission of NLV and provides evidence that direct infection with aerosolized viral particles occurs.

EuroRotaNet, a laboratory network, was established in order to determine the diversity of co-circulating rotavirus strains in Europe over three or more rotavirus seasons from 2006/2007 and currently includes 16 countries. This report highlights the tremendous diversity of rotavirus strains co-circulating in the European population during three years of surveillance since 2006/2007 and points to the possible origins of these strains including genetic reassortment and interspecies transmission. Furthermore, the ability of the network to identify strains circulating with an incidence of ⩾1% allowed the identification of possible emerging strains such as G8 and G12 since the beginning of the study; analysis of recent data indicates their increased incidence. The introduction of universal rotavirus vaccination in at least two of the participating countries, and partial vaccine coverage in some others may provide data on diversity driven by vaccine introduction and possible strain replacement in Europe.

Norovirus is the most frequent cause of acute infectious gastroenteritis and it is difficult to control in crowded environments like hospitals and nursing homes. Transmission depends on oral intake of virus deposited in the environment by infectious subjects. Data from volunteer studies indicate that virus concentrations in stool are highly variable, but systematic studies of the time-course of shedding and its individual variation are lacking. This paper quantifies norovirus shedding in a large population of 102 subjects, including asymptomatic shedders, and uses a longitudinal model to generalize shedding patterns. Enhanced surveillance for studies of transmission of norovirus in hospital outbreaks has yielded a considerable number of faecal samples from symptomatic and asymptomatic shedders, both from patients and staff. Norovirus concentrations were determined by real-time PCR. A quantitative dynamic model was fitted to the shedding data, in a multilevel Bayesian framework, to study the time-course of shedding and its variation. The results indicate that shedding in asymptomatic subjects is similar to that in symptomatic infections, both showing considerable variation in peak levels (average 105−109 /g faeces) as well as duration of virus shedding (average 8–60 days). Patients appear to shed higher numbers of virus than staff, for slightly longer durations, but the differences are too small to be significant. Given equal shedding, the greater contribution of symptomatic cases to transmission must be caused by their higher efficiency in spreading these viruses. The results of this study will be helpful for risk studies that need to quantify the deposition of virus in the environment.

Between April and September 1993, a nationwide outbreak of salmonellosis occurred in Germany which was traced to contaminated paprika and paprika-powdered potato chips. Of the estimated 1000 cases, children below 14 years were principally affected. Levels of 0·04–0·45 organisms per gram were found in the snacks. The infective dose was estimated at 4–45 organisms with an attack rate of 1 in 10000 exposed persons. The unique feature of the outbreak was the variety of serovars involved. S. saintpaul, S. rubislaw and S. javiana were isolated during the same time period from paprika powder, spice mixtures, snacks and patients. Their clonal identity was confirmed by molecular typing methods. Furthermore, monophasic and non-motile strains of rare salmonella O-groups were isolated from both paprika products and patients. This is the largest documented outbreak due to contaminated spices which proved that even extremely low numbers of salmonellae adapted to the dry state were able to cause illness.

1. A new phage-typing scheme for Salm. typhi-murium is described which initially defines thirty-four types of the organism.

2. Types recognizable with the older scheme of Felix and Callow remain distinct with the new system. However, the latter method offers a finer subdivision of the organism than does the former.

3. Thirteen of the twenty-nine typing phages used in the new scheme were prepared by adaptation of Salm. paratyphi B typing phage 3b, and nineteen are serologically indistinguishable from this phage.

4. The lysogenic properties of the new types are discussed. Twenty-three out of the thirty-three type strains yielded both thermolabile and thermostable phages and a further three yielded thermolabile phages only. No phages could be isolated from the remainder.

5. The distinctive host ranges of the phages carried by most types can be used for type identification.

I am indebted to Miss Alison M. Dykes for her valuable assistance with this work; to Mr F. J. Flynn for help in the preparation of phage stocks; and to Dr E. S. Anderson for many helpful discussions and advice in the preparation of this paper.

When Theodor Escherich (1885a, b) first described Escherichia coli he looked on it as a saprophytic organism. Soon several investigators found that colibacteria could be isolated from intestinal infections and from many infections outside the intestine, like urinary tract infections (UTI), cholecystitis, wound infections, meningitis, septicaemia, pulmonary infections, and many more. Uhlenhuth (1897) showed that coli strains from pathological processes were more pathogenic in animal experiments than strains isolated from the normal intestine. Smith (1927), who examined strains from white scours in calves, showed that spontaneous acapsular mutants could be obtained from certain colibacteria, and that such mutants were less virulent when injected intra-peritoneally into guinea-pigs.

Leafy vegetables are an essential component of a healthy diet; however, they have been associated with high-profile outbreaks causing severe illnesses. We reviewed leafy vegetable-associated outbreaks reported to the Centers for Disease Control and Prevention between 1973 and 2012. During the study period, 606 leafy vegetable-associated outbreaks, with 20 003 associated illnesses, 1030 hospitalizations, and 19 deaths were reported. On average, leafy vegetable-associated outbreaks were larger than those attributed to other food types. The pathogens that most often caused leafy vegetable-associated outbreaks were norovirus (55% of outbreaks with confirmed aetiology), Shiga toxin-producing Escherichia coli (STEC) (18%), and Salmonella (11%). Most outbreaks were attributed to food prepared in a restaurant or catering facility (85%). An ill food worker was implicated as the source of contamination in 31% of outbreaks. Efforts by local, state, and federal agencies to control leafy vegetable contamination and outbreaks should span from the point of harvest to the point of preparation.

It is generally accepted that the reservoir hosts of cowpox virus are wild rodents, although direct evidence for this is lacking for much of the virus's geographic range. Here, through a combination of serology and PCR, we demonstrate conclusively that the main hosts in Great Britain are bank voles, wood mice and short-tailed field voles. However, we also suggest that wood mice may not be able to maintain infection alone, explaining the absence of cowpox from Ireland where voles are generally not found. Infection in wild rodents varies seasonally, and this variation probably underlies the marked seasonal incidence of infection in accidental hosts such as humans and domestic cats.

The aim of this study was to compare the responses of colistin treatment alone vs. a combination of colistin and rifampicin in the treatment of ventilator-associated pneumonia (VAP) caused by a carbapenem-resistant A. baumannii strain. Forty-three patients were randomly assigned to one of two treatment groups. Although clinical (P = 0·654), laboratory (P = 0·645), radiological (P = 0·290) and microbiological (P = 0·597) response rates were better in the combination group, these differences were not significant. However, time to microbiological clearance (3·1 ± 0·5 days, P = 0·029) was significantly shorter in the combination group. The VAP-related mortality rates were 63·6% (14/22) and 38·1% (8/21) for the colistin and the combination groups (P = 0·171), respectively. Our results suggest that the combination of colistin with rifampicin may improve clinical and microbiological outcomes of VAP patients infected with A. baumannii.

In Salmonella typhimurium phage type 204c isolated in Britain, gentamicin resistance is specified by plasmids of the I1 compatibility group which also confer resistance to apramycin. These plasmids have been subdivided into three types within the I1 group on the basis of their antibiotic resistance specificity, their ability to produce colicin Ib and their restriction enzyme digest fragmentation patterns. All three have been identified in strains from cattle, but as yet only two types have been found in strains from humans.

It is suggested that the use of apramyein in animal husbandry is responsible for the appearance of gentamicin resistance in multiresistant strains of phage type 204 c, a phage type already epidemic in bovine animals and with an increasing incidence in humans.

A retrospective study of 191 cases of septic arthritis was undertaken at Royal Darwin Hospital in the tropical north of Australia. Incidence was 9·2 per 100000 overall and 29·1 per 100000 in Aboriginal Australians (RR 6·6; 95% CI 5·0–8·9). Males were affected more than females (RR 1·6; 95% CI 1·2–2·1). There was no previous joint disease or medical illness in 54%. The commonest joints involved were the knee (54%) and hip (13%). Significant age associations were infected hips in those under 15 years and infected knees in those over 45 years. Seventy-two percent of infections were haematogenous. Causative organisms included Staphylococcus aureus (37%), Streptococcus pyogenes (16%) and Neisseria gonorrhoeae (12%). Unusual infections included three melioidosis cases. Polyarthritis occurred in 17%, with N. gonorrhoeae (11/23) more likely to present as polyarthritis than other organisms (22/168) (OR 6·0; 95% CI 2·1–16·7). Univariate and multivariate analysis showed the hip to be at greater risk for S. aureus than other joints. Open arthrotomy was a more successful treatment procedure than arthroscopic washout or needle aspiration.

An epidemiological investigation was conducted to identify risk factors related to hygiene and husbandry practices which determine the introduction of Campylobacter spp. into broiler chicken flocks. All 176 broiler farms in an area in southeastern Norway participated in the study. Each farm was represented by one flock selected at random during a one-year period. The flocks were examined for Campylobacter colonization at slaughter, and the flock managers were sub-sequently interviewed about hygiene and husbandry practices. Campylobacter spp. were recovered from 32 (18%) of the flocks. The proportion of colonized flocks varied geographically and seasonally with a peak in the autumn. The following variables were found to be independently associated with an increased risk of Campylobacter colonization using logistic regression analysis: (i) feeding the broilers undisinfected water (odds ratio (OR) = 3·42, P = 0·045), (ii) tending other poultry prior to entering the broiler house (OR = 6·43, P = 0·007), (iii) tending pigs before entering the house (OR = 4·86, P = 0·037), (iv) geographic region (Hedmark versus Østfold county) (OR = 2·91), P = 0·023, (v) season (autumn versus other seasons) (OR = 3·43, P = 0·008). Presence of rats on the farm was associated with an increased risk, but this factor did not reach statistical significance (OR = 3·96, P = 0·083). Preventive measures should include dis-infection of drinking water and strict hygienic routines when the farm workers enter the rearing room. The results indicated that disinfection of drinking water is the preventive measure most likely to have the greatest impact on the prevalence of Campylobacter among broiler chicken flocks in the study area (population attributable fraction = 0·53).

A protracted outbreak of Norwalk-like virus (NLV)-associated gastroenteritis occurred in a large hotel in North-West England between January and May 1996. We investigated the pattern of environmental contamination with NLV in the hotel during and after the outbreak. In the ninth week, 144 environmental swabs taken from around the hotel were tested for NLV by nested RT–PCR. The sites were categorized according to the likelihood of direct contamination with vomit/faeces. The highest proportion of positive samples were detected in directly contaminated carpets, but amplicons were detected in sites above 1·5 m which are unlikely to have been contaminated directly. The trend in positivity of different sites paralleled the diminishing likelihood of direct contamination. A second environmental investigation of the same sites 5 months after the outbreak had finished were all negative by RT–PCR. This study demonstrates for the first time the extent of environmental contamination that may occur during a large NLV outbreak.

A relatively simple and safe apparatus for the study of airborne infection is described.

Cloud sampling and assessment techniques are described and critically discussed. Evidence is given concerning the satisfactory reproducibility of in vitro and in vivo assays.

Limitations to the usefulness of the apparatus are noted.

The world's first documented toxoplasmosis outbreak associated with a municipal water supply was recognized in 1995 in Victoria, British Columbia, Canada. It was hypothesized that domestic cat (Felis catus) or cougar (Felis concolor) faeces contaminated a surface water reservoir with Toxoplasma gondii oocysts. An extensive investigation of the Victoria watershed 1 year following the outbreak documented the presence of an endemic T. gondii cycle involving the animals inhabiting the area. Cats and cougars were observed throughout the watershed. Serological evidence of T. gondii infection was demonstrated among domestic cats living in the Victoria area. Cougars were found to shed T. gondii oocysts. Serological evidence of T. gondii infection in deer mice living in the riparian environments of the watershed suggested that T. gondii oocysts were being shed near the water edge. Contamination of Victoria's water supply with T. gondii oocysts potentially occurred during the study period and future waterborne toxoplasmosis outbreaks in this and other communities are possible.

Until recently, reports on methicillin-resistant Staphylococcus aureus (MRSA) in food production animals were mainly limited to occasional detections in dairy cattle mastitis. However, since 2005 a MRSA clone, CC398, has been reported colonizing pigs, veal calves and broiler chickens and infecting dairy cows. Many aspects of its prevalence in pigs remain unclear. In other livestock, colonizing capacity and reservoir status still require elucidation. MRSA CC398 has also been detected in meat, but, as for other MRSA, the risk this poses is somewhat unclear. Currently, the most worrying aspect of MRSA CC398 appears to be its capacity to spread to humans. This might complicate MRSA control measures in human healthcare, urging research into risk factors and transmission routes. Although infections with MRSA CC398 are much less reported than carriage, more investigation into its pathogenic potential is required. Moreover, the origin and evolution of this clone remain unknown.

Wild boars are important disease reservoirs. It is well known that abundance estimates are needed in wildlife epidemiology, but the expense and effort required to obtain them is prohibitive. We evaluated a simple method based on the frequency of faecal droppings found on transects (FBII), and developed a spatial aggregation index, based on the runs test statistic. Estimates were compared with hunting data, and with porcine circovirus and Aujeszky's disease virus seroprevalences and Mycobacterium tuberculosis complex and Metastrongylus spp. prevalence. The FBII and the aggregation index were correlated with the hunting index, but both of the former estimates correlated better than the latter with the disease prevalences. Hence, at least in habitats with high wild boar densities, the FBII combined with the aggregation index constitutes a cheap and reliable alternative for wild boar abundance estimation that can be used for epidemiological risk assessment, even outside the hunting season and in areas with no available data on hunting activities.

The haemolytic streptococci associated with scarlet fever, tonsillitis, septic conditions, etc., belong to one group or species designated Streptococcus pyogenes.

Cultural and serological aids to the identification of Str. pyogenes are described.

The epidemiologically significant types of Str. pyogenes appear to be about 20 in number, though probably more than thirty type sera will be necessary for the complete analysis of the group. So far twenty-seven individual serological types have been defined.

The irregularities which have been observed in the agglutination reactions of streptococcal cultures are ascribed chiefly to variations in type-specificity.

Different colonies may give “type-specific” or “group” agglutination, and these distinctions are revealed macroscopically in the case of certain types by growth on homologous agglutinating serum agar.

Some examples are given of observations on the epidemiology of streptococcal infections in schools and other institutions.

The principles involved in the serological classification of a bacterial group are discussed.

Our aim was to obtain knowledge of how meteorological conditions affect community epidemics of respiratory syncytial virus (RSV) infection. To this end we recorded year-round RSV activity in nine cities that differ markedly in geographic location and climate. We correlated local weather conditions with weekly or monthly RSV cases. We reviewed similar reports from other areas varying in climate. Weekly RSV activity was related to temperature in a bimodal fashion, with peaks of activity at temperatures above 24–30°C and at 2–6°C. RSV activity was also greatest at 45–65% relative humidity. RSV activity was inversely related to UVB radiance at three sites where this could be tested. At sites with persistently warm temperatures and high humidity, RSV activity was continuous throughout the year, peaking in summer and early autumn. In temperate climates, RSV activity was maximal during winter, correlating with lower temperatures. In areas where temperatures remained colder throughout the year, RSV activity again became nearly continuous. Community activity of RSV is substantial when both ambient temperatures and absolute humidity are very high, perhaps reflecting greater stability of RSV in aerosols. Transmission of RSV in cooler climates is inversely related to temperature possibly as a result of increased stability of the virus in secretions in the colder environment. UVB radiation may inactivate virus in the environment, or influence susceptibility to RSV by altering host resistance.