1. An epidemic of a dysenteroid nature, largely ambulatory, due to B. dysenteriae (Sonne), affecting some 100 nurses without transference to any hospital case in the wards served by this section of the nursing staff, is described.

2. Sonne's bacillus was isolated from sixteen out of forty-two cases examined.

3. The probable cause was infection of food during preparation in the kitchens by a carrier.

4. A case of infection from laboratory cultures is described.

5. Notes are given of investigations upon the colonial appearance, biochemical and agglutinogenic reactions and pathogenicity to rabbits of the organism isolated, and also upon the presence of agglutinins in the blood of infected cases.

6. One case of infection in a rabbit by feeding experiments is described.

A virus was isolated from fifteen of nineteen children living in an infants' home during an outbreak of diarrhoea. The virus possesses many of the characteristics of the enterovirus group but is serologically distinct from any of the accepted members of this group. It is non-pathogenic for unweaned mice, non-cytopathic in tissue cultures of monkey kidney, but is rapidly cytopathic for tissue-cultured cells of human origin. It is serologically similar to virus Hu 659 isolated by Abrahams in the United States (personal communication).

I should like to thank the Director-General of Public Health and State Psychiatric Services, New South Wales, for permission to publish.

Amongst 1267 healthy children 6 months to 4.5 years of age in Adelaide, the pneumococcal carriage rate from a single nasal swab sampling was 29% in the period 1980–1. Of 269 children, sampled monthly on five occasions, 91% carried a pneumococcus on one or more occasions: 55% carried a single type, 33% carried two types, 2% carried three types and 1% carried four types; 18% carried a pneumococcus on either 4 or 5 occasions. The commonest types encountered were types 6, 19 and 23 in that order, and these three types constituted 57% of the total: other common types(> 5% of the total) were types 14, 15 and 11, and the six commonest types constituted 77% of the total. Of these, types 6, 14, 19 and 23 commonly cause systemic disease in children; on the other hand types 11 and 15 cause disease infrequently. The number of strains showing antimicrobial drug resistance was low: on quantitative testing 0.7%of 291 isolates examined showed relative resistance to benzylpenicillin and 0.7% were resistant to tetracycline; 10.9% of 230 isolates examined showed resistance to co-trimoxazole; dual or multiple drug resistance was not detected, and all isolates tested were susceptible to chloramphenicol, erythromycin, lincomycin and rifampicin.

The work contained in the following paper demonstrates that valuable evidence of the relative incidence of bovine and human tuberculosis may probably be obtained by a careful record of the chances of contact infection in each case.

The material dealt with was derived from a central clinic in a large industrial Country Borough(Newport, Mon.) and from a series of smaller clinics. Two of the latter were in industrial (coal and iron) districts and three in small country towns containing semi-urban and rural populations.

A transportable surgery cross-flow unit has been tested under ‘operational conditions’. By the use of artificial aerosols and a volunteer surgical team, or dummies, it was found that, at an air velocity of 0·45 m./sec., a detectable transfer to above the table occurred only when quite highly concentrated aerosols (of more than 103·6 bacteria/m.3 of air or more) existed underneath the table. The short disappearance time under these conditions and the quite stable flow pattern above the table found when a surgical team was working, standing along both sides of the table, make it unlikely that an aerosol of detectable concentration can develop during surgery, at this site. The chance that particles, liberated from the heads of the surgical team, settle on the table, was found to be strongly reduced when a cross-flow tunnel operated at an air velocity of 0·45 m./sec. The transfer from outside the unit to the inside was prevented by closing the upper part of the open front side.

The villages selected for the present series of observations were Dhand and Kasel in the Arnritsar District of the Punjab. They are situated about 10 miles south-west of Amritsar City and within a distance of ¾ mile of each other. They are typical Punjab villages of about 2,000 and 4,000 inhabitants respectively.

A survey has been made of the different theories put forth to explain the nature of ultra-microscopic viruses, and it has been concluded as probable that they are representatives of some precellular forms of life. The writer's views have been given, and the probabilities have been expounded regarding the constitution of these forms, their evolution towards a composite cell, the conditions under which they exist, the means by which they obtain the necessary energy for their vital processes, and their food requirements. It has been suggested that at times some unit of a cell may undergo a partial or complete reversion to the independent precellular form. The possibility of the existence of other primitive forms of life, belonging to another biological world, has also been considered. The theories discussed have been analysed in relation to the known facts concerning virus diseases, transmissible bacteriolysis and cancers.

The reorganisation of the laboratories and the fitting up of various electrical and timing equipment, which were necessary to test the theories experimentally, have been explained, and a description has been given of some of the special pieces of apparatus made in the workshop for the experiments.

Experiments were carried out on an extensive scale with animal and vegetable materials containing known viruses, with muds, etc., presumed to contain precellular forms of life, and with bacteriolytic agents. Certain delicate bacteria, isolated from porcelain filtrates, were used as controls.

Attention was first given to indicators for growth, and it was found that minute quantities of selenium oxychloride incorporated in media resulted in many bacteria growing with a bright red colour.

From an extensive series of experiments on nutritive requirements, it was determined that beef extracts usually act detrimentally on bacteria, and they should not be used. The detrimental effect was marked with the bacteriolytic agents. Good agar media were gradually evolved. Rain water proved to be better than water from a town supply. A watery extract from certain clays supplied sufficient nourishment for many bacteria, but the media were improved by the addition of watery extracts of bracken ash and of the fronds of certain ferns, notably those belonging to the Asplenium group.

The associated conditions used during cultivation were varied in many ways, particular attention being given to the influence of solar rays and the energy emitted from projector lamps. In different experiments the wave energy was modified by reflection or filtration, different bands being tested both consecutively and intermittently. The materials used consisted of lenses, prisms, natural rocks and crystals, as well as animal, vegetable and chemical filters.

Many bacteria were found to tolerate solar rays when cultivations were made on suitable media, particularly if the action was intermittent. They were least tolerant to the region of the spectrum around 4000 Å.

A spore-bearing bacillus has been obtained from cultures of a mud nitrate on a leaf mould extract medium, placed under the intermittent influence of filtered solar rays. A group of the colonies developed a homogeneous waxy change, which was proved to be associated with a dissolution of the spores. It is suggested that the change is due to the presence of a “sporolytic agent”, although it has not been found possible to demonstrate the agent in a porcelain filtrate.

In a number of cases pleomorphic bacilli have been cultivated from old porcelain filtrates obtained from various diseased plants and muds. Many were found to be very sensitive as to their nutritive requirements. Most of them grew well in subdued daylight and under the influence of a 100-watt projector lamp.

Other porcelain filtrates produced granules on the surface of certain experimental media. When subcultures were made, granules associated with a marked milky opalescence of the medium occurred along the line of inoculation. No bacterium could be found in films made from the granules. The phenomenon appeared only on tubes of media which were autoclaved, set and inoculated on the same day. The milky opalescence can be produced without the presence of an unheated filtrate. The significance of the granules is being investigated.

Many comparative experiments have been carried out with suspensions of dead micrococci, either uninoculated or inoculated with living micrococci or a bacteriolytic agent or with both. It has been shown that suspensions of dead bacteria undergo more marked clearing when placed under the influence of solar or other rays than when placed in darkness. The effect is increased when the suspensions are prepared from cultures grown on tubes of media which have been autoclaved, set and inoculated on the same day, and it is particularly marked when the suspensions have been inoculated with living micrococci. The significance of these and other results has been considered, and attention has been called to the utilisation of the factors concerned for the purpose of freeing intracellular toxins in the preparation of various vaccines.

In conclusion I should like to record my appreciation of the valuable services rendered by my only assistant, Mr H. Frankham, the laboratory attendant and caretaker of the Institution.

In August 1988 an increase was noted in the number of cases of cryptosporidiosis identified by the microbiology laboratory at Doncaster Royal Infirmary. By 31 October, 67 cases had been reported. Preliminary investigations implicated the use of one of two swimming pools at a local sports centre and oocysts were identified in the pool water. Inspection of the pool revealed significant plumbing defects which had allowed ingress of sewage from the main sewer into the circulating pool water. Epidemiological investigation confirmed an association between head immersion and illness. The pools were closed when oocysts were identified in the water and extensive cleaning and repair work was undertaken. The pool water was retested for cryptosporidial oocysts and found to be negative before the pool re-opened.

1. When chick embryo cell monolayers were infected with ultrasonically treated elementary body suspension by a short period of adsorption some of the adsorbed virus lost infectivity in a few minutes. This was followed by a more gradual loss during incubation of the cultures. The lowest point was reached at 4–6 hr. followed by a rise in titre due to production of new virus at 7–8 hr. The quantitative assessment of these changes is discussed.

2. In such cultures, titration of intact and disintegrated cells after incubation for 4–5 hr., indicated an eclipse phase by showing an absence of infective virus in cells which ultimately produced it. The process of eclipse continued for several hours. With inoculum that had not been subjected to ultrasonic treatment it was not possible to show this by infecting HeLa cell monolayers.

3. Ultrasonically treated inoculum, compared with a similar, but untreated inoculum, had a three to flvefold higher titre. The virus units in it were more uniformly capable of infecting cells. After its adsorption to monolayers a rapid loss of some infective virus occurred within a few minutes which was not demonstrable with untreated inoculum. During incubation of monolayers infected with treated inoculum the loss of infectivity was faster, there was a more rapid production of new virus and a greater yield. The nature of the changes in the virus which were brought about by ultrasonic treatment have not been explained, but the use of such an inoculum markedly affected the results of experiments.

4. Treatment of infected monolayers with trypsin or EDTA caused the cells to shed as much as half their virus. This virus would not be released spontaneously into the medium or removed from monolayers by washing. This applied to all periods of incubation up to 24 hr. or more when marked increase of virus had occurred.

5. The disintegration of infected cells by ultrasonic treatment was efficient in releasing infective virus from them, although it was not possible to be certain all the virus in the cells was rendered detectable by this technique.

6. The effect of some technical procedures on the interpretation of results is discussed.

The use of a single-radial-haemolysis technique for the detection of antibody to rubella virus is described. The single-radial-haemolysis test was compared with the standard HI methods for the detection of antibody to rubella virus. A close correlation between the two methods was observed in a survey of over two thousand serum samples and the study indicated that single-radial-haemolysis was highly satisfactory as an assay method for IgG antibodies to rubella virus. It was found that the immuno-globulins active in SRH tests sedimented in the 7S range in sucrose rate gradients and were presumably immunoglobulins of the IgG class, but 19S iinmunoglobulins did not produce haemolysis.

We have recently had the opportunity of studying a plague epidemic that broke out on Terceira Island, Azores, in 1908. Terceira Island contains a population of 45,000 souls, the epidemic spread over 27 parishes. About 260 persons were attacked, with a mortality of about 48%.

Restriction fragment length polymorphism of the gene encoding rRNA (ribotyping) was used in combination with conventional epidemiological markers to study phenotypic variations among Streptococcus agalactiae of bovine origin and the possible epidemiological interrelationship between the bovine and human reservoirs of Streptococcus agalactiae.

The bovine material constituted 53 strains (9 antigen combinations) isolated from 11 herds. Herds with a uniform as well as heterogenic antigenic pattern were included. Furthermore, strains isolated in the course of time from the same persistently infected quarters were examined. The human material constituted 16 strains, 4 each of 4 serotypes, isolated from healthy carriers. Finally, nine serotype- and the group reference strains were examined. All strains were serotyped by double diffusion in agarose gel, biotyped (lactose ±), and ribotyped using two restriction enzymes, Hind III and Hha I.

All isolates could be typed by ribotyping and seven ribotypes were identified among the reference strains. The restriction enzymes used alone or in combination gave typing results that allowed discrimination between and within serotype. Combined use of serotype, HindIII and HhaI ribotypes produced 11 types among the 16 human strains. Ribotype analysis discriminated between herds infected with the same serotype. Strains of varying antigenic patterns from the same herd had the same ribotype. Phenotypic variations in serotype observed in persistent intramammary infection were not related to genetic changes as monitored by ribotype. Two ribotypes were represented among both bovine and human strains. The discriminating capability of lactose fermentation was of limited value.

A mathematical model was used to estimate malaria transmission rates based on serological data. The model is minimally stochastic and assumes an age-dependent force of infection for malaria. The transmission rates estimated were applied to a simple compartmental model in order to mimic the malaria transmission.

The model has shown a good retrieving capacity for serological and parasite prevalence data.