A carrier has been found of at least three phage types of Salmonella paratyphi B. Investigation has shown that phage-mediated conversion could account for this multiplicity of types according to the following scheme.

It is not possible, however, to exclude the actual occurrence of repeated infection with different phage types.

I am grateful to Dr E. S. Anderson of the Central Enteric Reference Laboratory, Colindale, for his interest and advice during the course of this investigation, and to Dr Helen A. Wright of the University of Edinburgh who provided the many cultures and so introduced me to this problem.

The laboratory method here outlined and utilized by us over the past 11 years, of examining and judging ice-cream on a milk basis, appears to pro-vide a sieve of mesh generous enough to let through the passably ‘fit’ while stopping the presumably ‘doubtful’ and ‘unfit’.

Eighty-six samples of Alexandria milk ice-creams collected from various vendors in the city by Army Inspectors during the autumn months of 1944 showed, on this method, about 19% ‘unfit’—a result in remarkable agreement with fifty-eight samples from Municipal sampling, collected earlier in the year during summer months, which showed 16% ‘unfit’.

A small number of samples collected after hygienic control of the process of manufacture by Army Inspectors resulted in a total disappearance of unfit samples. The improvement arising from this controlled experiment was estimated at a lowering of 60% in total bacteria per c.c., and a reduction of 77% in coliforms.

The results of the latter experiment show what good results can be achieved in the betterment of milk ice-creams by simple hygienic measures, and should be more widely known in all centres where members of the Services are large consumers of ice-cream.

Acknowledgements are due to Lieut. J. T. S. Templeman, R.A.M.C., and his staff for their part in this investigation; and to Lieut.-Col. G. P. M. Marshall, R.A.M.C., A.D.H., for instigating the experiments on hygienic control of production.

Effective use of data linkage is becoming an increasingly important focus in the new healthcare system in England. We linked data from the results of a multiplex PCR assay for respiratory viruses for a population of 230 inpatients at a UK teaching hospital with their patient administrative system records in order to compare the mortality and length of stay of patients who tested positive for influenza A(H1N1)pdm09 with those positive for another influenza A virus. The results indicated a reduced risk of death among influenza A(H1N1)pdm09 patients compared to other influenza A strains, with an adjusted risk ratio of 0·25 (95% confidence interval 0·08–0·75, P = 0·01), while no significant differences were found between the lengths of stay in the hospital for these two groups. Further development of such methods to link hospital data in a routine fashion could provide a rapid means of gaining epidemiological insights into emerging infectious diseases.

It has been reported that foetal death follows a seasonal pattern. Influenza virus infection has been postulated as one possible contributor to this seasonal variation. This ecological study explored the temporal association between the influenza activity and the frequency of foetal death. Time series analysis was conducted using weekly influenza-like illness consultation proportions from the Danish sentinel surveillance system and weekly proportions of spontaneous abortions and stillbirths from hospital registers from 1994 to 2009. The association was examined in an autoregressive (AR) integrated (I) moving average (MA) model and subsequently analysed with cross-correlation functions. Our findings confirmed the well-known seasonality in influenza, but also seasonality in spontaneous abortion. No clear pattern of seasonality was found for stillbirths, although the analysis exposed dependency between observations. One final AR integrated MA model was identified for the influenza-like illness (ILI) series. We found no statistically significant relationship between weekly influenza-like illness consultation proportions and weekly spontaneous abortion proportions (five lags: P = 0.52; 11 lags: P = 0.91) or weekly stillbirths (five lags: P = 0.93; 11 lags: P = 0.40). Exposure to circulating influenza during pregnancy was not associated with rates of spontaneous abortions or stillbirths. Seasonal variations in spontaneous abortion were confirmed and this phenomenon needs further investigation.

A village epidemic of brucellosis, due to Brucella melitensis, contracted from infected sheep and goats owned by the vifiagers is described. Of the 309 inhabitants eighty-four became infected and seventy-nine were clinically ill with brucellosis. The investigation covered 232 of the total population and nearly all those not examined belonged to the age group, 0–5 years, not directly exposed to infection by contact with diseased animals.

The population of the village was made up of forty-six families, only nine of which escaped infection. In the affected families, the incidence varied from one to seven in each case. The size of the family varied from three to eleven but there was no correlation between the size of the family and the number contracting brucellosis, neither did sex play any part in the incidence. All age groups were susceptible but the morbidity increased with age and this was correlated with increased risk of exposure to infection of the older age groups.

There was considerable variation in the severity of the clinical illness but there were no fatiities and all patients responded to antibiotic therapy.

Brucella melitensis was isolated from twenty-eight of the thirty-six patients subjected to blood culture and specific agglutinins at an acceptable level were demonstrated in all but three of those with a clinical illness.

The number of persons without evidence of clinical brucellosis who possessed significant brucella agglutinins was very small and the assumption that in an endemic area the number of infected persons is much greater than the number clinically ill was not borne out in the outbreak described here.

Persistence of specific agglutinins up to 2 years after recovery from the clinical illness is recorded.

We wish to pay tribute to the late Professor J. Gurevitch for his constant interest and helpful advice.

Thanks are due to Prof. M. Ruiz Castaneda for providing us with the Castaneda bottles for blood culture work, to Dr E. Neeman of the Government Brucella Reference Laboratory for supplying the Standard Brucella Antigen and for examining the strains of Brucella isolated, and to Colonel H. J. Bensted for his interest and help in preparing the paper. Finally, we are indebted to Mrs Aliza Abut Kayner, social worker in the village health centre, for her valuable help in gathering statistical data.

Coronavirus disease 2019 (COVID-19) emerged from a city in China and has now spread as a global pandemic affecting millions of individuals. The causative agent, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is being extensively studied in terms of its genetic epidemiology using genomic approaches. Andhra Pradesh is one of the major states of India with the third-largest number of COVID-19 cases with a limited understanding of its genetic epidemiology. In this study, we have sequenced 293 SARS-CoV-2 genome isolates from Andhra Pradesh with a mean coverage of 13324X. We identified 564 high-quality SARS-CoV-2 variants. A total of 18 variants mapped to reverse transcription polymerase chain reaction primer/probe sites, and four variants are known to be associated with an increase in infectivity. Phylogenetic analysis of the genomes revealed the circulating SARS-CoV-2 in Andhra Pradesh majorly clustered under the clade A2a (20A, 20B and 20C) (94%), whereas 6% fall under the I/A3i clade, a clade previously defined to be present in large numbers in India. To the best of our knowledge, this is the most comprehensive genetic epidemiological analysis performed for the state of Andhra Pradesh.

The supernatant fluids of batch and continuous cultures of Brucella strains contained up to 100 mg/i of soluble RNA which could be recovered by precipitation with lysozyme. This RNA fraction had many of the properties of ribosomal RNA and was single-stranded, sensitive to ribonuclease, with an approximate sedimentation constant of 5S, a molecular weight of about 35000 daltons and an adenine; guanine; cytosine; uracil content of 17·5 26·5 33; 23 mol% respectively. RNA fractions from lysozyme precipitates evoked high titres of Brucella agglutinins on injection into rabbits and induced acute inflammatory responses in guinea-pig skin. Highly purified RNA fractions prepared by phenol extraction of lysozyme precipitates did not evoke antibodies to Brucella abortus.

The poliomyelitis epidemic of 1937 in Denmark was investigated by means of information obtained about each individual case.

It occurred in the usual season, culminating in September. The districts involved were limited largely to Zealand, including Copenhagen. It is of particular interest that the disease occurred also in rural districts that were the sites of similar epidemics in 1933 and 1934.

It is noted as a peculiar fact that poliomyelitis seems to be unable to invade the whole of Denmark within one season.

The 1937 epidemic comprised 1200 notified cases, of whom 599 developed paralysis and 113 died. Everything suggests that the number of non-paralytic cases was far greater than the number of cases notified. Influenza and angina were notified with striking frequency in the districts where poliomyelitis prevailed.

The morbidity, frequency of paralysis and mortality were greater among males than among females.

A change in the age distribution during the past 35 years is pointed out. In 1937, 30% of the patients were over 15 years, and about 14% over 20 years; of those who died 45% were over 15 years, 20% over 20 years.

Convalescent serum was not employed in Copenhagen, but in the provinces 489 patients were treated with, and 400 without, serum. The principles of the treatment were the same as in 1934. Serum was given early in the disease, as a rule intravenously.

The clinical and microbiological characteristics of catheter-related bloodstream infection (CR-BSI) due to uncommon microorganisms was assessed in a retrospective case-control study over a 9-year period in a tertiary teaching hospital. Uncommon microorganisms were defined as those representing <0·5% of all CR-BSI. Diagnosis of CR-BSI required that the same microorganism was grown from at least one peripheral venous blood culture and a catheter tip culture. Thirty-one episodes of CR-BSI were identified due to 13 different genera and these accounted for 2·3% of all CR-BSI in the hospital. Although these infections were not associated with increased mortality, they occurred in patients with more severe underlying conditions who were receiving prolonged antibiotic therapy.

Our data suggest that there are four different thermolabile antigens in S. dysenteriae (Shiga) appearing in different combinations in the five variants described. These antigens are:

1. The agglutination-inhibiting factor ‘I’, found in variants 1 and 3, which is a typical surface antigen.

2. A precipitinogen, ‘N’, probably identical with the neurotoxin, found in variants 1, 2 and 5.

3. A labile precipitinogen, ‘A’, in the extracts of variants 1 and 2, occurring in the deeper layers of the bacterial cell.

4. An additional precipitinogen, ‘B’, found in extracts of variants 1, 2, 3 and 4. It differs from the other labile antigens as its combining- and immunizing-powers are not destroyed by heating at 100° C. for 2 hr.

THe experiments recorded here were initiated following upon the occurrence in this country of foot-and-mouth disease in a cow, which a short time previously had been injected for the purpose of inducing oestrus with a pituitary extract imported from the Continent. Mr D. A. E. Cabot, M.R.C.V.S., Chief Veterinary Officer of the Ministry of Agriculture, made reference to this interesting case in a discussion on foot-and-mouth disease at the First Imperial Veterinary Conference held in London (1938). Confirmation of the nature of the infection was obtained by the inoculation of test animals under experimental conditions with suitable material collected from the injected animal. Further investigations were made. Three ampoules containing pituitary extract were obtained from the distributors in London of the imported commercial preparation under discussion. These ampoules belonged to the same batch as the ampoule with the extract from which the cow had been inoculated. Messrs A. Eccles, M.R.C. V.S. and A. M. Graham, M.R.C.V.S., at the Experimental Station of the Foot-and-Mouth Disease Research Committee at Pirbright, tested this material for virus infectivity by the inoculation of cattle and guinea-pigs. They reported that all three samples of pituitary extract were contaminated with the virus of footand-mouth disease. In addition they produced evidence that the immunological type of the virus recovered from the extract in the ampoules was the same as that of the virus recovered from the cow, viz. Vallée and Carré 0. This and additional information left no doubt that the outbreak of the disease had been produced by the inoculation of the pituitary extract, and further that this extract had been prepared from the pituitary glands of cattle, which were very probably in the early stages of infection with foot-and-mouth disease at the time of slaughter.

Sera from healthy blood donors from different parts of New Zealand, collected between 1977 and 1980, were analysed by the microagglutination technique for antibodies against Brucella abortus. Populations from both urban and rural areas were studied. The technique was shown to be capable of handling the 3351 sera studied and thus to be a useful screening test to assess the immune status of large populations. The results demonstrated some of the effects on the human population of the successful bovine brucellosis eradication programme.

In a previous paper (Williams and Hoy, 1927) it was shown that living and virulent tubercle bacilli could be demonstrated in the faeces of six apparently healthy cows from among a total of 391 which were examined. All these cows were living the normal life of the herds in which they were discovered, and three of them were brought to the Institute in order that a study might be made of the frequency with which tubercle bacilli could be found in their faeces.

Readmission of asymptomatic methicillin-resistant Staphylococcus aureus (MRSA) carriers may contribute to the hospital reservoir. Using an electronic alert system, we assessed the weight of readmission of known MRSA carriers on MRSA colonization pressure in a hospital setting. During the 2004–2010 period, 2058 alerts were generated for 1060 inpatients. A total of 486/1060 patients (46%) were readmitted at least once, and 330/486 (64·4%) were readmitted <3 months after discharge. A mean of 20 MRSA patients were present on the same day (from 40 in 2004 to eight in 2010). The number of MRSA patient-days was 34 575, i.e. 2·5% of the 1 366 277 patient-days of the study period, and 17 737 (51·3%) MRSA patient-days were due to readmission of known MRSA carriers. The number of new MRSA cases was partly correlated with the number of MRSA patients hospitalized (R2 = 0·49). Rapid electronic identification of these patients proved essential in decreasing the global burden of MRSA in our hospital.

Recent New Zealand and Australian isolates of Salmonella typhimurium phage type 179 were studied for relatedness by colony incompatibility. This established that all but one strain of the New Zealand groups probably formed a clone despite carrying a variety of plasmids. The Australian strains showed a far greater diversity. This study demonstrates the epidemiological usefulness of the colony incompatibility reactions.

In a study of the influence of environmental and other conditions on the growth and nutrition of the children of the poorer classes in the city of Glasgow, it seemed desirable to determine how far a homogeneous stock was being dealt with since there was some danger that racial variations might modify the results of the investigation.

1. During the summer months 1928–9 an epizootic occurred in De Aar and neighbouring districts among small veld rodents, mainly affecting Namaqua gerbilles (Desmodillus auricularis).

2. Many of the animals dying showed a haemorrhagic septicaemia, the causative organism of which appeared to be a Pasteurella rather smaller in size than Pasteurella (Bacillus) pestis.

3. In a considerable proportion of the animals found dead there was no obvious septicaemia.

4. A description is given of the Pasteurella, which is believed to be a hitherto undescribed species, and for which the name Pasteurella desmodilli is suggested.

5. This organism was found to be highly pathogenic for rabbits, less so for guinea-pigs and mice, and non-pathogenic for rats and fowls.

6. It was found by Rhodes to be highly pathogenic for Lobengula gerbilles (Tatera lobengulae) from Cape Town, but for animals of this species from Johannesburg it proved to be much less virulent, and even when it killed them there was frequently no septicaemia.

7. The above observation seems to indicate the presence of a considerable degree of immunity among the Johannesburg lobengulas, as compared with those from Cape Town.

8. It is suggested that a similar condition of partial immunity among the Namaqua gerbilles (for which there is other evidence adduced) might account for the finding of many of them dead without obvious septicaemia.

9. The existence of this disease introduces a complication in the diagnosis of plague among veld rodents.

Monitoring of malaria intensity in terrain regions of Arunachal Pradesh, India is very difficult as the dynamics of mosquito populations varies to a large extent due to altitude and frequent changes in climatic conditions. There is a scarcity of information on the influence of climatic factors on malaria morbidity in Arunachal Pradesh. Hence, a pilot study was conducted from 2006 to 2010 to understand malaria transmission dynamics, seasonal distribution and disease morbidity. Plasmodium vivax and P. falciparum are the two major parasites for malaria transmission in Arunachal Pradesh. Out of 142 558 malaria cases analysed from 2006 to 2010, P. vivax infection contributed 72·1% followed by P. falciparum (27·9%). However, the overall morbidity of malaria declined from 37/1000 in 2006 to 18/1000 population in 2010. From this study it was observed that the temporal distribution of malaria cases varied between districts and high morbidity rates were reported mostly during the wet season. To understand malaria transmission dynamics in the study area, the Richards model was used to predict malaria cases. The output of the results from this model predicted a higher number of malaria cases (K) during 2006 and a gradual decline in subsequent years. Similarly, the growth rate r, and exponential deviation α, were almost identical for all the years, which shows that the Richards model is the most suitable model for the prediction of malaria cases.

The purpose of the present study was to identify Echinococcus multilocularis infection in follow-up of 95 subjects initially seropostive by Emc-ELISA or Emf-ELISA antibody assays and to compare the utility of these assays with specific Em2plus-ELISA and ultrasound screening for E. multilocularis infection. At follow-up seven subjects were seropositive with both methods, while three were seropositive only with Emc-ELISA and 11 only with Emf-ELISA. All subjects were seronegative with Em2plus-ELISA. There were no manifestations of E. multilocularis infestation by ultrasonographic screening. Seropositivity on Emc-ELISA and Emf-ELISA screening tests does not appear to correlate with manifest alveolar echinococcosis identified by ultrasound. A recommendation for further follow-up of subjects found to be seropositive with Emc-ELISA and Emf-ELISA but with no sonographic evidence of disease is not justified at this time.