Wild Norway rats (Rattus norvegicus) from several habitats were tested for their susceptibility and resistance to warfarin. Animals were fed 0·005% warfarin in ground oatmeal for periods varying from 1 to 12 days. Rats having no prior exposure to anticoagulants were shown to be susceptible, none having survived a 6-day feeding period. Resistant rats were found on two farms where anticoagulant materials had been used intensively for about 20 years.

Methods are described for the isolation and identification of aerobic bacteria occurring naturally in the hind-gut of the cockroach Blatta orientalis captured from a number of wild sources, to establish whether or not human pathogens occurred naturally within the gut. During the investigation an organism was frequently found which could not be classified in any described species, and for which we propose the name Escherichia blattae.

Particle concentration in patient rooms at various ventilation rates and with differing methods of air supply has been investigated experimentally in a specially built test room. The size of the test room corresponded to an ordinary bedroom for two patients. Air was supplied isothermally to this test room, either through induction units or through a perforated ceiling, and the number of air changes per hour varied from 1 to 16. When the air was supplied by means of induction units, tests with different airflow patterns in the room were also carried out. The principle of the measurements was to estimate the decrease in particle concentration at certain points when the initial concentration was uniform all over the room and no generation took place during the measuring period. Talc powder was used as test dust, and the particle concentration was measured at up to six points in the room with a particle counter.

Salmonella javiana, a serotype rarely isolated in Australia, has been recovered from the faeces of a 14-month-old infant with symptoms of enteritis.

The child had been closely associated with a marsupial species, the quokka, during a vacation on Rottnest Island in Western Australia, and S. javiana was isolated from faecal pellets from adult quokkas, and also from a snake collected on the island.

Sampling revealed a high incidence of Salmonella infection in the quokkas. In all, 62 out of 87 animals (71%) were found to be infected, and 17 Salmonella and 3 Arizona serotypes were identified from 100 isolations comprising 92 salmonellas and 8 arizonas. Multiple infections were frequently detected and up to four serotypes were recovered from individual animals. S. javiana was isolated from four quokkas.

A close parallel was observed between the serotypes isolated from quokkas and sea-gulls on the island, and abattoir effluents, lake waters, bird droppings and reptiles sampled on the adjacent mainland.

The epidemiological significance of Salmonella and Arizona infections in the quokka population and their possible association with the seasonal decline in condition and numbers of animals on Rottnest Island is discussed.

Salmonella typhimurium strain 1566 administered to mice by the intraperitoneal route was considerably more lethal than the same dose administered subcutane-ously. This could be measured hi terms of mortality, infectivity and mean survival time of those mice that died.

Intranasal vaccines of inactivated or living attentuated A2/Hong Kong influenza viruses were compared for clinical acceptability, serological effects and protective efficiency against natural epidemic influenza in a large industrial and clerical population.

Methods of maintaining and feeding and of infecting cockroaches with pathogenic organisms were investigated.

Cockroaches fed on known concentrations of Escherichia coli 0119, Esch. coli O1, Alkalescens Dispar O group 2 and Shigella dysenteriae 1 (Shiga's Bacillus) were maintained in Petri dishes. The effect of various diets on the survival of these organisms within the hind-gut and faeces was observed. With a ‘normal’ diet of gruel Esch. coli 0119 was isolated for up to 20 days, Esch. coli O1 for 17 days and ADO 2 for 15 days. Sh. dysenteriae 1 was isolated only sporadically to the third day.

The sequential development of the immune response in nasal washings was studied in 54 volunteers immunized with either attenuated or inactivated influenza B/Eng/13/65 virus vaccines.

Eleven of the 15 volunteers given the inactivated vaccine by deep subcutaneous inoculation showed no rise in nasal wash protein or immunoglobins due to the immunization procedure nor was specific neutralizing antibody detected in their nasal washings after immunization. Neutralizing antibody was detected in nasal washings of three volunteers in this group who also showed a 20-fold or greater increase in serum haemagglutinin-inhibiting antibody after immunization and in one volunteer who had antibody present in pre-trial nasal washings.

Eleven of 15 volunteers who were successfully infected by the live attenuated vaccine showed a characteristic rise in protein and IgA and IgG immunoglobin concentrations in nasal washings 5–14 days after the administration of the live virus vaccine. Neutralizing antibody was detected in the nasal washings of these 11 volunteers and appeared at the same time as or 1–2 days after the initial rise of protein and immunoglobin. Neutralizing antibody was also detected in the nasal washings of one other volunteer who did not show a rise in protein or immunoglobin concentration in nasal washings after immunization.

IgA was detected (⋟ 3 mg./lOO ml.) in the majority (84%) of nasal wash specimens which had a protein concentration of 0·2 mg./ml. or greater while IgG was not detected (⋟ 4·5 mg./lOO ml.) until the protein concentration rose to 0·4 mg./ml. or greater. The geometric mean concentration for normal nasal wash protein in this study was 0·3 + 0·1 mg./ml.

Regression analysis indicated that the concentrations of both IgA and IgG immunoglobins were directly proportional to the protein concentration in nasal washings but that this relationship varied considerably between individuals.

Absorption studies indicated that neutralizing and haemagglutinin-inhibiting antibodies in nasal secretion to influenza B/Eng/13/65 virus were predominantly associated with the IgA class of immunoglobin.

An analysis was made of the spread of foot-and-mouth disease during the epidemic in Hampshire in January and February 1967. To explain the pattern of spread, it had to be postulated that virus was present seven days before the first outbreak was reported. It is suggested that the disease occurred initially in pigs fed on infected meat and that the virus was subsequently disseminated from the local abattoir, where the pigs were killed, to four farms by movement of animals, slaughterhouse waste, people or vehicles, and to fifteen by the airborne route. Subsequent spread from these farms was by movement in two instances and by the airborne route in five. The source and route of infection of the last farm in the outbreak were not determined.

The risk of spread through movement was associated more with carriage of infected slaughterhouse waste, movement of animals, people or vehicles carrying animals than through collection of milk, artificial insemination or movement of other types of vehicles. Outbreaks of disease among pigs gave rise to more secondary spread than outbreaks in cattle. Secondary outbreaks attributed to airborne spread occurred only in ruminants. Most airborne spread was into areas of high livestock density and cattle in the larger herds became infected. Airborne spread could be correlated with wind direction and speed but not with rain. The reduction in the number of outbreaks at the end of the epidemic could be attributed to the elimination of the largest sources of virus, the control of movements and the fact that in all instances except two the wind was blowing virus over towns and out to sea, to areas of low stock density and to areas where animals had been killed.

Two different types of inclusion bodies have been found by electron-microscopy in the cytoplasm of sectioned lymphocytes from children infected with measles.

The first is tubular, 18 nm. internal diameter, embedded in osmiophilic material, and is found during the incubation period. It is not thought to be specific for measles, and is probably identical with structures recently reported in HEp-2 cell lines and tumour tissue.

The second type is less obviously tubular and morphologically resembles measles nucleocapsid. This was found only after the rash had appeared.

After one passage of influenza A2/Singapore/l/57 virus in mice treated with 150 mg./kg./day of aminoadamantane, a partially drug-resistant strain of virus was detected in 1 of 12 mice. The isolation rate of aminoadamantane-resistant viruses increased to 8 after three passages in drug-treated mice. Some virus strains showed a 500-fold increase in resistance to aminoadamantane and to the structurally related compounds α-methyl-1-adamantane methylamine and 2-adamantanamine sulphate. No aminoadamantane-resistant viruses were detected after passage of influenza four times in mice treated with lower (15 or 1·5 mg./kg./day) concentrations of aminoadamantane. Aminoadamantane had no detectable effect on the development of lung lesions in mice infected with the drug-resistant influenza strain, whereas lung lesions were reduced in aminoadamantane treated mice infected with a control strain of influenza A2/Singapore virus. No differences were detected in the buoyant density in caesium chloride, morphology or serology between control and aminoadamantane-resistant strains of virus. These drug-resistant influenza viruses may be useful for detailed studies of the mode of action of aminoadamantane.

Recent studies have established that the occurrence of common cold epidemics amongst men in Antarctica shows a pattern similar to that seen in other isolated communities such as Tristan da Cunha (Cameron & Moore, 1968; Shibli, Gooch, Lewis & Tyrrell, 1971). Colds occur during relief periods when ships and aircraft call, and disappear during the months of winter isolation, but no statistical analysis of the incidence of such colds is available.

Summer thermal sensations of secondary schoolchildren in England are compared with those earlier published for winter. Heat stress, contrary to expectation, is seen to decrease during the warm months, and neutrality is found to increase by some 6° F. (3·5° C.) air temperature, which is more than double the increases observed for adults under similar circumstances.

Six of 12 men wintering at an isolated Antarctic base sequentially developed symptoms and signs of a common cold after 17 weeks of complete isolation. Examination of specimens taken from the men in relation to the outbreak has not revealed a causative agent.

Relative rates of proportionate mortality from cancer of six sites based on total cancer deaths and the proportions expected in all towns, and from four types of cardiovascular disease based on total deaths from all causes, have been related in the 80 county boroughs of England and Wales to the sources of water supply and to the average hardness of water in. the towns. The sources of water, from upland surfaces, artesian wells and rivers, were classified in eight groups, and significant associations were found for cancers of the stomach, oesophagus, prostate, male bladder and female breast, and for hypertensive and chronic rheumatic heart disease. No associations were apparent with intestinal cancer, vascular disease of the nervous system or arteriosclerotic heart disease. Hardness or softness of the water was classified in seven groups and significant associations were found for the same diseases as for source of water, none being evident for coronary disease.

Two tests are described for detecting antibody to the type-specific opacity factor (OF) of group A streptococci. This antibody was detected among patients convalescent from streptococcal sore throat in two communities in which out-breaks due to opacity factor-producing strains of group A streptococci occurred.

In an outbreak due to streptococci of M-type 22 there was a close correspondence between the distribution of anti-OF and of bactericidal M-antibody for the type. In a smaller outbreak due to M-type 58 streptococci, however, M-antibody was detected more often than antibody of OF.

The somatic and flagellar serum agglutinin titre were determined in paired samples obtained from seventy-seven cases of bovine abortion associated with Salmonella dublin infection. The cases could be divided into four serological groups with an active infection being demonstrated in most cases. The serum agglutination test was shown to be a relatively specific diagnostic test but was of more limited value in the retrospective identification of convalescent cases.

Regular examination of rectal swabs revealed the presence of very low numbers of trimethoprim resistant Escherichia coli in the faeces of 10 batches of calves successively reared in the same shed and none of these strains transferred trimethoprim resistance to E. coli K12. All the calves had received oral doses of 30 mg/kg day of trimethoprim-sulphadiazine for 5 consecutive days. From two subsequent batches of calves reared in the same shed, however, several isolations were made of E. coli with transmissible R factors determining trimethoprim and streptomycin resistance. Shortly before these strains were detected, isolations of E. coli with similar properties had been made from other calves, in a different shed, which had been fed much higher doses of trimethoprim-sulphadiazine. Serological evidence indicated that all the E. coli isolated carrying this R factor belonged to the same strain, which had apparently spread from the second shed to the first. No evidence of ‘in vivo’ transfer of the R factor to other enteric bacteria was obtained.

Data for mortality from cancer of the cervix in England and Wales by 5-year age groups and four quinquennia (1951–70) are analysed. The logarithms of the mortality rates are regressed on age group, epoch of death and epoch of birth. The factors obtained are considered in relation to particular features of the mortality pattern, such as the reversal of trend in certain age groups.

To find out the salmonella carrier rate, 1980 samples comprising faeces, mesenteric lymph nodes, liver and spleen were collected from 812 sheep and 683 goats slaughtered for food. In all 72 salmonella strains from 51 animals (25 sheep and 26 goats) were isolated. These represented 22 salmonella serotypes. The public health significance of these findings is discussed.