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.

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.

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 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.

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.

Modified Moore's swabs, placed in sewers for 5 days, were used to concentrate salmonellas from sewage. Duplicate cultures of swab strips in selenite broth were incubated at 41 and 37°C. respectively. Salmonella organisms were recovered consistently from the swabs when the enrichment broths were incubated at 41°C., However, when equal portions of the same swabs were incubated at 37°C., only 22% of them yielded Salmonella organisms. These results indicate an advantage in incubating the selenite broths at 41°C. rather than 37°C. in attempting to isolate salmonellas from sewage.

One hundred and fifty faecal samples were examined for salmonellas by culture in selenite broths incubated at 41 and 37°C. Twelve (8%) samples were positive at 41°C. compared to only 10 (6·7%) positive samples at 37°C. This difference is not statistically significant to indicate an advantage of the elevated-temperature of incubation over the conventional temperature in attempting to isolate salmonellas from human faeces. Moreover, results of the recovery rates of S. paratyphi B, S. typhi, and S. typhimurium indicate that an incubation temperature of 37°C. is more appropriate for recovering salmonellas from artificially infected faecal samples than an incubation temperature of 41°C. This stresses the inability of laboratory studies to mimic conditions in nature.

H phase II → phase I conversion of Salmonella thompson was studied at different temperatures. All strains were isolated from one outbreak, and a convenient method of phase conversion was sought. In our hands this was best effected at 20° C.

This report has been complied by the Secretary, Dr P. Nicolle, from the material provided by the Directors of National Centres and of some Regional Centres of the ICEPT. It was delivered at the meeting of the ICEPT during the 10th International Congress of Microbiology on 8 August 1970 in Mexico. The English version was prepared and edited by the Chairman, Dr E. S. Anderson.

The incidence of Salmonella in tortoises and frogs captured in Istanbul was studied. From 31 out of 40 tortoises (77·5%) and from 16 out of 311 frogs (5·1%) salmonella strains belonging to 18 and 14 serotypes respectively were isolated.

Respiratory disease on Tristan da Cunha has been observed since the islanders returned in 1962. An epidemic of unprecedented severity occurred in the winter of 1971 and involved 273 (96%) of 284 islanders, 92 of whom had two attacks. The epidemic was apparently introduced by the Tristania.

The illness of both first and second attacks ranged from mild to severe but there were some differences. There were two deaths, both in elderly persons with chronic chest disease and heart failure. Serological evidence suggests that this was due to influenza A2 of the Hong Kong serotype H3N2

Ferrets infected with influenza virus A2/Hong Kong/3/68 responded with a febrile reaction; the temperature was elevated by 1·0°C. or greater to a level of 40°C. or more. In addition, relatively high titres of virus were recovered from nasal washings taken 3 days after virus infection, serum antibody was produced, increased nasal protein was detected and nasal washings contained both HI and neutralizing antibody. Of four ferrets immunized with 400 CCA units of inactivated influenza virus A2/Aichi/2/68 in saline, only one produced detectable serum HI antibody, and none produced detectable nasal antibody. These ferrets were subsequently found to be susceptible to intranasal infection with influenza virus A2/Hong Kong/3/68. Thus, the temperature response, the titre of virus recovered from nasal washings and the serum HI antibody response found after virus infection was similar to that found after infection of non-immunized ferrets. However, the increase in protein concentration and the titre of HI and neutralizing antibody found in nasal washings after virus infection was detectably less than that found after virus infection of non-immunized ferrets.

Four ferrets were immunized with 400 CCA units of inactivated A2/Aichi/2/68 virus in adjuvant 65, and these ferrets produced relatively high titres of serum HI antibody but no detectable nasal antibody. After subsequent virus infection with influenza virus A2/Hong Kong/3/68, these ferrets showed a modified temperature response, reduced titres of virus in nasal washings compared to that found in nasal washings from non-immunized ferrets, no increase in nasal protein and no detectable nasal HI antibody. Thus, immunization with inactivated virus in adjuvant 65 resulted in a significant modification of the response of ferrets to challenge virus; however, the immunity was not complete, and appreciably less than that found after infection with live homologous virus.

Necropsy blood from cases diagnosed as dying from influenza A was examined for specific antibody in the IgG, IgA and IgM fractions and a specific diagnosis of recent infection was made if either IgM or IgA antibody and low titres of IgG antibody were found. By these criteria a diagnostic rate of 77% was found in those cases from whom no virus was isolated. The use of infected cell monolayers grown on polytetrafluoroethylene-coated slides gave a simple method of carrying out these antibody assays, and the use of necropsy blood did not require any special methods of transport of specimens to the virus laboratory.

The high incidence (80·1%) of Pseudomonas aeruginosa pyocine type 1 in bovine mastitis in Israel suggested some degree of selectivity under local conditions. Contrary to other reports, cattle and calves showed a high rate of faecal carriage of this organism. The water supply on farms was often contaminated. The presence of certain pyocine types in the udder, gut or water occasionally led to their transmission from one reservoir to another; however, many types did not seem to spread.

P. aeruginosa was found in association with infections in various animals and was present in many locations such as a mouse breeding house and a chick hatchery.

The direct fluorescent antibody test was assessed for detection of Brucella abortus in bovine abortion material. Br. abortus organisms could be readily detected as characteristic intra-cellular clumps, in smears stained with fluorescent antibody. Counterstaining with Evans Blue was necessary to suppress tissue auto-fluorescence. The method was specific and enabled brucella infection to be differentiated, inter alia, from Q-fever infection.

The extraction of group A streptococcal antigens by group C phage-associated lysin has been confirmed. In addition to the T antigen the extract contained M-protein, group-specific polysaccharide and mucopeptide antigen which was difficult to remove. This method of extraction of the T antigen was compared with the trypsin method. The latter method was found to be of advantage in giving a pure specific antigen.

The results of routine bacterial and viral studies on 483 patients with whooping cough, investigated at one hospital over a five year period are presented. The possible role of respiratory viruses in the aetiology of the disease is discussed.

The socio-economic status of 80 patients with infectious mononucleosis was compared with the socio-economic distribution of the general population in the same area of south-west London. An excess incidence of infectious mononucleosis was observed among subjects from upper socio-economic groups. A possible relationship between this observation and the epidemiology of the Epstein—Barr virus is discussed.

Serological investigations were carried out on 147 patients with Paul—Bunnell positive infectious mononucleosis (IM) from the general population. All possessed antibody to the Epstein—Barr virus (EBV) and 63% showed serological evidence of recent infection. Contacts of 132 patients, 306 in all, were followed serologically; within 6 months of the index cases' illness twenty one contacts developed evidence of EBV infection or re-infection and of these five developed overt IM. The secondary attack rate of EBV infection among susceptible contacts was at least 19%; the corresponding figure for clinically apparent IM was 6%. EBY antibody prevalence among patients' siblings was significantly lower than among age-matched controls, suggesting that cases of IM come from families with a lower than normal previous experience of the virus. Of thirteen patients with persistently Paul—Bunnell negative ‘glandular fever’ four had serological evidence of recent EBV infection and two had probable cytomegalovirus mononucleosis. Recent EBV infection may have been associated with the illnesses of five of the remaining patients.

The virulence of T-mycoplasmas for cattle was tested by examining their ability to produce mastitis in cows. It was found that both virulent and avirulent strains of T-mycoplasmas can be isolated from cattle. All of four strains from pneumonic calf lungs and a strain from a case of bovine kerato-conjunctivitis caused mastitis but only two of four strains isolated from the urogenital tract of cows were virulent. None of the human, simian or canine T-mycoplasmas examined were able to cause mastitis in cattle. However, a bovine strain was found to be capable of causing mastitis in goats. Virulent and avirulent strains from the same and different species contain common antigens detected by the metabolic inhibition test. Pathogenicity could not be shown to be characteristic of any particular serotype. The possibility is raised of some species barrier being responsible for the inability of non-bovine strains to infect cattle.

A one-year epidemiological investigation was made in an isolation ward for burned patients. The transmission of Staphylococcus aureus was mainly studied. In spite of the design of the ward the cross-infection rate was high. In all, 49 of 69 patients were infected 114 times. Twenty-six of the strains causing infection were found in a patient only, 10 in a member of the staff only and 23 in both patients and staff the week before they caused a new infection. There were three epidemic outbreaks caused by three strains of Staph. aureus all belonging to phage group III; one was resistant to methicillin. Environmental studies with settle plates showed that the number of staphylococci dispersed by a burned patient was often very high. In 8% of the observations in occupied bedrooms the air count of Staph. aureus was more than 1800 col./m.2 hr. However, the counts of Staph. aureus in the corridor and service areas were low. This seems to indicate a rather good protection against airborne transfer of bacteria. Other routes of infection were probably of greater importance.