The prevalence and spatial distribution of Escherichia coli serogroups O26, O103, O111 and O145 in calves <7 days old in New Zealand and their relationship with serum IgG, weight and sex was determined by collecting recto-anal mucosal swabs (RAMS) (n = 299) and blood samples (n = 299) from two slaughter plants in the North Island. Real-time PCR of RAMS enrichment cultures revealed that 134/299 samples were positive for O26, 68/299 for O103 and 47/299 for O145, but none were positive for O111. Processing of positive enrichment cultures resulted in 49 O26, four O103 and five O145 isolates. Using multiplex PCR 25/49 (51%) O26 isolates were positive for stx1, eae, ehxA, 17/49 (34·7%) for eae, ehxA and 7/49 (14·2%) for eae only. All O103 and O145 isolates were positive for eae, ehxA only. O26 isolates were grouped into four clusters (>70% similarity) using pulsed field gel electrophoresis. Mapping of the farms showed the presence of farms positive for O26, O103 and O145 in three important dairy producing regions of the North Island. Calves positive for O103 were more likely to be positive for O26 and vice versa (P = 0·04). Similarly, calves positive for O145 were more likely to be positive for O103 and vice versa (P = 0·03). This study demonstrates that non-O157 E. coli serogroups of public health and economic importance containing clinically relevant virulence factors are present in calves in the North Island of New Zealand.

Much evidence of immunogenic heterogeneity among the LC strains of Mycoplasma mycoides ssp. mycoides emerged from cross-immunization and hyperimmunization experiments in mice in which three LC strains (Vom/Plum Island, 74/2488, and Mankefår 2833) were used for challenge purposes. All heterologous LC-strain vaccines cross-immunized against the three challenge strains, but protection was usually only ‘partial’, i.e. significantly less than that given by homologous vaccine. Cross-hyperimmunization with all heterologous LC but not SC strains produced protection against challenge with Vom/Plum Island that was virtually ‘complete’, i.e. similar to that produced by homologous vaccine. Challenge with 74/2488 gave generally similar results; but against Mankefår 2833 six heterologous LC vaccines gave complete protection and six did not.

Vaccines prepared from the Smith (1423) strain of M. mycoides ssp. capri gave some protection against Vom/Plum Island but none against 74/2488 or Mankefrr 2833. The cross-immunizing ability of three further M. mycoides ssp. capri strains appeared to resemble that of Smith (1423).

In a cross-hyperimmunization experiment, vaccines prepared from SC strains of M. mycoides ssp. mycoides varied greatly in their ability to protect against challenge with strains 74/2488 and Mankefår 2833.

Clostridium botulinum causes infant botulism by colonising the intestines and producing botulinum neurotoxin in situ. Previous reports have linked infant botulism cases to C. botulinum spores in household dust, yet the baseline incidence of C. botulinum spores in residential households is currently unknown. Vacuum cleaner dust from 963 households in 13 major Canadian cities was tested for C. botulinum using a novel real-time PCR assay directed against all known subtypes of the botulinum neurotoxin gene. None of the samples tested positive for C. botulinum. Analysis of a random subset of samples by MALDI Biotyper revealed that the most common anaerobic bacterial isolates were of the genus Clostridium and the most common species recovered overall was Clostridium perfringens. Dust that was spiked with C. botulinum spores of each toxin type successfully produced positive real-time PCR reactions. These control experiments indicate that this is a viable method for the detection of C. botulinum spores in household dust. We make several recommendations for future work that may help discover a common environmental source of C. botulinum spores that could lead to effective preventative measures for this rare but deadly childhood disease.

Case identification is an ongoing issue for the COVID-19 epidemic, in particular for outpatient care where physicians must decide which patients to prioritise for further testing. This paper reports tools to classify patients based on symptom profiles based on 236 severe acute respiratory syndrome coronavirus 2 positive cases and 564 controls, accounting for the time course of illness using generalised multivariate logistic regression. Significant symptoms included abdominal pain, cough, diarrhoea, fever, headache, muscle ache, runny nose, sore throat, temperature between 37.5 and 37.9 °C and temperature above 38 °C, but their importance varied by day of illness at assessment. With a high percentile threshold for specificity at 0.95, the baseline model had reasonable sensitivity at 0.67. To further evaluate accuracy of model predictions, leave-one-out cross-validation confirmed high classification accuracy with an area under the receiver operating characteristic curve of 0.92. For the baseline model, sensitivity decreased to 0.56. External validation datasets reported similar result. Our study provides a tool to discern COVID-19 patients from controls using symptoms and day from illness onset with good predictive performance. It could be considered as a framework to complement laboratory testing in order to differentiate COVID-19 from other patients presenting with acute symptoms in outpatient care.

Fluoroquinolone use before tuberculosis (TB) diagnosis delays the time to diagnosis and treatment, and increases the risk of fluoroquinolone-resistant TB and death. Ascertainment of fluoroquinolone exposure could identify such high-risk patients. We compared four methods of ascertaining fluoroquinolone exposure in the 6 months prior to TB diagnosis in culture-confirmed TB patients in Tennessee from January 2007 to December 2009. The four methods included a simple questionnaire administered to all TB suspects by health department personnel (FQ-Form), an in-home interview conducted by research staff, outpatient and inpatient medical record review, and TennCare pharmacy database review. Of 177 TB patients included, 72 (41%) received fluoroquinolones during the 6 months before TB diagnosis. Fluoroquinolone exposure determined by review of inpatient and outpatient medical records was considered the gold standard for comparison. The FQ-Form had 61% [95% confidence interval (CI) 48–73] sensitivity and 93% (95% CI 85–98) specificity (agreement 79%, kappa = 0·56) while the in-home interview had 28% (95% CI 18–40) sensitivity and 99% (94–100%) specificity (agreement 68%, kappa = 0·29). A simple questionnaire administered by health department personnel identified fluoroquinolone exposure before TB diagnosis with moderate reliability.

H9 avian influenza virus played a key role during generation of the novel H7N9 virus. A surveillance programme was conducted to assess the H9 virus in relation to the risk of H7N9 virus contamination in the environment. Risk of H7N9 virus contamination in the presence of H9 virus was higher than without (adjusted odds ratio 4·49, 95% confidence interval 3·79–5·31). Adjusted odds ratios of the H7N9 virus associated with co-presence of H9 virus and interacting factors were 4·93 (rural vs. urban area), 46·80 (live poultry markets vs. other premises), 6·86 (Huzhou vs. Hangzhou prefecture), 40·67 (year 2015 vs. 2013), and 9·63 (sewage from cleaning poultry vs. poultry faeces). Regular surveillance on gene variability of H7N9 and H9 viruses should be conducted and extra measures are needed to reduce co-circulation of H7N9 and H9 viruses in the environment.

We have no desire to claim for the tests described above that they will be found applicable to every strain of organism belonging to any particular group. Our experiments were necesarily limited to a few races of each—many of these being probably avirulent from long subcultivation on artificial media. We merely wish to indicate the general methods we would adopt in any case of difficult bacteriological diagnosis, although as a matter of fact the only tests we found it necessary to use in the course of our work were the method of cutaneous and subcutaneous inoculation into animals and the stalactite test.

The tests referred to in this paper may be summarised thus:

1. The plague bacillus gives a fairly characteristic type of colony on neutral agar; it forms typical stalactites in neutral broth; it gives certain definite fermentation reactions.

2. B. pseudotuberculosis resembles B. pestis more closely than any other organism. The animal test on white rats is probably the best for its differentiation.

3. Bacilli of the haemorrhagic septicaemia group appear to be inhibited in their growth in media containing sodium taurocholate.

4. Bacilli of the B. enteritidis (Gaertner) group are the most readily distinguished of all; the appearance of agar cultures, the negative stalactite test, and their fairly definite fermentation sugar reactions are sufficient to mark them off from the plague bacillus.

The conclusions I seek to draw from this part of my investigations are:—

1. That a malarial form of horse-sickness probably occurs naturally.

2. That when animals which are either naturally relatively susceptible, such as the donkey, ox, and goat, or animals which have acquired protection, e.g. “salted” horses, are inoculated with virulent horse-sickness blood, their blood conveys a modified infection of horse-sickness which is malarial in type.

3. That this malarial from is associated with the presence of parasites within the red corpuscles of the blood of the infected animal.

4. That the blood of “salted” horse which have been previously regularly inoculated during several months is of a dangerous order of virulence. Vide former experiments.

5. That the blood of “salted” horses which have only been once inoculated after several months' rest conveys a fairly severe fever.

6. That the blood of “salted” horses, which have not been inoculated for even a year, can still convey infection.

7. That “unsalted” horses which have been inoculated a year previously with “salted” blood convey only a week infection.

8. That a severe attack of malarial horse-sickness gives a considerable degree of protection against subsequent inoculation with “salted” blood.

9. That when regularly inoculated “salted” horses are used to produce blood giving severe fever, such fever may become so severe as to cause death with symptoms of horse-sickness.

10. That the blood of the latter animals which die can produce virulent horse-sickness in clean horses, if used in a considerable dose, i.e. 20 c.c.

Among 30 strains of leptospires isolated from samples of sewage taken before and during treatment at two sewage plants in England, only one appeared to belong to Leptospira interrogans, the species that comprises the leptospires that are pathogenic to man and animals. That strain, Compton 746, was isolated from settled sewage, before treatment at a treatment plant that deals mainly with human sewage. It was shown serologically to belong to serogroup Tarassovi and appears to represent a new serovar that has been named mogdeni after the name of the sewage plant, Mogden, from which it was isolated.

Attention was first directed to the presence of a substance in milk acting as a complement by Pfaundler and Moro(1) and from that time onwards there has been much conflicting evidence published on this subject. Kopf(2) stated that complement could not be demonstrated in milk, using the method of Pfaundler and Moro, and the work of Sassenhagen and Bauer(3) would seem to show that complement is not present in milk unless the milk of cows suffering from mastitis be present. Sassenhagen(4) in a later paper states that complement is present in the colostrum of cows and goats and that it disappears as lactation progresses. Lane-Claypon(5) has followed Pfaundler and Moro and states that complement can be found in almost any milk.

A bacteriological survey on the distribution and occurrence of coliforms and pathogenic indicators of pollution within the surf-zone and near-shore waters along a section of the Natal coast before the use of submarine outfalls was reported previously. In that report more than half the beaches in the region were found to be of Class IV or III quality. After the submarine outfalls became operational, ten further sampling runs were made. A considerable improvement in the sea-water quality was apparent, most of the beaches being regraded to Class II or I, notably in the bathing areas.

Samples of frozen precooked rock lobster meat from five South Australian fish-processing plants situated in the West Coast and south-east regions were tested over a period of six months during the 1974/5 lobster fishing season. The most probable number (MPN) of E. coli and coliforms, Staphylococcus aureus and Salmonella, as well as total plate count (TPC) were determined in 480 samples. Monthly geometric mean TPC ranged from 1600/g to 25,000/g. The highest geometric mean of the MPN of coliforms and E. coli were 4·9/g and 1·8/g respectively. The highest geometric mean number of staphylococci was 18·6/g. Salmonella was not detected in the 480 units tested. Only 0·4% of the samples had TPC exceeding 100,000/g. Coliforms and E. coli were not present in 76·1% and 92·7% respectively of the samples tested. Staphylococcus aureus was not detected in 67·7% of the samples. The numbers of organisms in 82% of the samples fall within the microbiological standards proposed by the National Health and Medical Research Council of Australia for frozen precooked foods. The results of this study demonstrate the microbial quality of precooked lobster meat attainable when good manufacturing practices are used.

DURING the last six years (1899—1904) some fifteen thousand examinations of material from throats for the diphtheria bacillus have been made at the Lister Institute. The localities from which this material has been derived have naturally been widespread and varied; much of the work however has been done for local authorities in and near London, and the sources of origin of the major part of the material have not varied very much during the whole period under review.

No information from official or non-official sources is available on the prevalence of enteric fevers in Palestine in pre-war days. Since the establishment of the British Administration (1919) the Annual Reports of the Government Department of Health invariably emphasise the high incidence of enteric fevers. Several papers dealing with the epidemiology of the disease appeared in the Hebrew periodicals Briuth Haam and Harefuah and in 1926 an elaborate Report was submitted to the Department of Health by a Committee of Enquiry appointed by the Department to consider and advise on the situation as regards enteric fever in the country. The data thus accumulated, although very valuable for the local health authorities, did not reveal any peculiar features of more than local interest. Their publication abroad seemed, therefore, superfluous.

“Virulence” is an ill-defined term and its use frequently gives rise to disputes, which remain unresolved because the disputants have no common basis other than that the term applies to organisms which cause disease. Thus it is imperative that the writer clearly defines the meaning of the term virulence as used in this paper, that the issue may not be confused by the reader approaching the subject from a different point of view.

1. Coliform and paracolon β strains agglutinated to a high titre with OB antisera from two strains of Escherichia coli O111B4H2.

2. The presence of β antigen in some strains of Esch. coli O111B4H2 has been shown and therefore such strains should be classified as plus β forms. This factor could not be demonstrated by agglutination tests but was evident by its ability to produce and absorb β antibodies.

3. The dissociation and complex nature of β forms was discussed.

The writer wishes to express her thanks to Prof. S. D. Rubbo for his helpful criticism of the manuscript.

A modification of the metabolic inhibition test for titrating poliomyelitis antibody is described. The method depends on the substitution of galactose for glucose in the initial medium to eliminate colour change during the period of virus activity. Neutralization is detected by the addition of glucose at the end of the period, when the usual colour changes associated with this type of test occur. A statistical analysis of the results obtained is given.

This method can also be used for titrating antibodies to other enteric viruses.

Thanks are due to Dr Hélène Mair, Dr D. R. Gamble and Dr A. D. Macrae for strains of enteroviruses, and to Miss Patricia Jerram, for valuable technical assistance in the early days of this work.

1. In a group of boys, revaccinated 12 years after primary vaccination in infancy, 37 per cent, gave “immune” reactions to vaccine virus.

2. Immune reactions were more than twice as common in those boys with two or more old vaccination scars than those with one.

3. When the number of scars was held constant there was no tendency for groups with large scars to be more immune than those with small scars.

4. The average area of a single old scar was smaller in the “immunes” than in the rest of the group.

5. The substitution of a vaccination technique consisting of one insertion of lymph with a minimum of trauma, for two or three insertions by “crosshatched” scarifications was followed by nearly a threefold fall in the recorded vaccinia morbidity, and a halving of the number of days' sickness attributed to vaccinia.

The following account of a milk-spread epidemic of scarlet fever in the burgh of Elgin may be of interest to those who are at times faced with similar problems.

HISTORY

The number of cases of scarlet fever notified in the burgh each year from 1920 to 1938 is given in Table 1. This table also shows that the periods of

Table 1. Scarlet fever notifications, 1920–38

maximal incidence, centring on 1921, 1926 and 1934, are related roughly to the periods of maximal incidence of all cases in the area, which area includes the counties of Moray and Nairn and the burghs situated within the counties. A prolonged epidemic occurred in the whole area from 1933 to 1935, the age distribution of cases at different stages of that epidemic (Douglas, 1935) being given in Table 2. It is regretted that present circumstances do not permit of a more detailed analysis of the age and sex distributions of this epidemic. There was no evidence that the disease was spread by milk.