Sera from 823 wild rabbits (Oryctolagus cuniculus) collected from a number of geographic regions of Victoria, Australia over the past eight years were examined for antibodies to Encephalitozoon cuniculi, along with sera from 46 hares (Lepus europaeus) (Pallas) and 57 New Zealand wild rabbits. No sera were positive, implying that this common laboratory rabbit parasite is absent from wild rabbits in these areas. However, wild rabbits were found to be readily infected by the oral route with small numbers of tissue-culture-grown spores of E. cuniculi. A possible explanation for the absence of encephalitozoonosis in wild rabbits is that E. cuniculi infection places them at a biological disadvantage for survival. The natural hygiene habit of wild rabbits may also significantly decrease post-natal infection.

In a study comparing the responses of institutionnalized Down's syndrome (DS) and non-Down's (ND) inmates to enterovirus infections, the frequency of wild enteric viruses and the excreation patterns of oral polio vaccine (OPV) viruses were similar in both groups. Antibody titres developed to poliovirus types 2 nad 3 following vaccination were similar in DS and ND and ND vaccinees, but the responses to type I virus was signifcantly less in DS vaccinees. As judged by the development of poliovirus antibody in non-vaccinees, the spread of virus from OPV-immunized to unimmunized subjects in the institution was not noticeably different in DS and ND subjects.

An unexpected finding was that the excretion patterns of all three serotypes of poliovirus were strikingly similar for each individual to individual. The similarity of excreation occurred despite wide differences within an individual in the titres of neutralizing serum antibodies to the three serotypes. It is suggested that the rate at which a given individual eliminates enteroviruses may be largely determined by factors, the activities of which atre not reflected in serum antibody titres.

The sex ratios and the emergence patterns of the European rabbit flea bred under animal house conditions were examined. An overall preponderance of female fleas was found. This was due to the greater preponderance of female fleas in the primary emergence, whereas the sex ratios in the secondary emergence were about 1:1.

Serological typing was used as an epidemiological tool in the investigation of 524 outbreakes of Clostridium perfringens food poisoning in the United Kingdom and 37 outbreaks in other countries.

Five thousand five hundred and fifty-four (77%) of 7245 strains of C. perfringens association 561 outbreaks were typable with the 75 Food Hygiene Laboratory antisera; in 354 (63%) of these outbreaks were typable with the 75 Food Hygiene Laboratory antisera; in 354 (63%) of these outbreaks a specific serotype was established as being responsible for the outbreak.

An assessment is made of the ability of two additional sets of antisera, prepared against 34 American and 34 Japanese strains of C. perfringens, to increase the number of strains which can be typed. The extent of cross-reaction between the three sets of antisera was determined and the results are discussed in relation to the source and history of the type strains.

Gram-negative anaerobic bacilli isolated from specimens submitted to the routine diagnostic bacteriology laboratory and regarded as significant pathogens were identified by conventional bacteriological tests; 399 strains isolated from 356 specimens submitted from 332 patients were studied and most were readily identified by the results of a combined set of morphological, biochemical, tolerance and antibiotic disk resistance tests. B. fragilis has particular pathogenic potential and was the commonest species isolated, accounting for < 50% of strains. The next commonest was B. asaccharolyticus with 55 strains, and 16 other species or groups were represented by smaller numbers. Many (68%) were from infections related to the gastro-intestinal tract, but there were significant numbers from infections of the male and female genito-urinary tracts, the head, neck and central nervous system and from a variety of soft tissue infections. Most infections were mixed, and a pure culture of a Bacteroides sp. was obtained from only 26% of infections; two or more strains of Bacteroides were recovered from 55 infections. The specific identification of Bacteroides may help the bacteriologist to judge the significance of laboratory findings, influence the patient's management and prognosis and help determine the source of infection.

Biotyping by the scheme of Duguid et al. (1975) of 2010 cultures of Salmonella typhimurium received by the Scottish Salmonella Reference Laboratory in 1974–6, the definitive phage types of which were known, revealed 137 different phage type/biotype groups. Four major epidemic clones, comprising 52 % of the cultures, were recognized: 1/2a, 49/26a, 56/17g and 141/9f. The sources of each of these four groups of strains were primarily bovine (587 cultures) and human (361), suggesting a close association between infections in the two hosts.

Epidermiological evidence showed that most of the outbreaks were caused by cultures of a single phage type/biotype, suggesting that both phage typing and biotyping characters were usually stable in the course of spread of epidemic strains.

Thirty-two of the 63 phage types contained strains of more than one biotype. Cultures from 11 of the phage types were of two or more closely related biotypes and those from 21 others were of unrelated or distantly related biotypes. The combined use of phage typing and biotyping made it possible to detect occasional variations in the phage type or biotype in epidemic clones during their spread, e.g. phage type 49 to 204, 56 to 193, 141 to 193 and biotype 2a to lOa, 9f to 9bf, or 9cf, 26a to 26f.

The increasing use of intensive cytotoxic chemotherapy for patients with solid tumors enhances the risk of opportunistic infection to levels formerly seen only in patients with acute leukaemia, and prevention of infection is a major concern. A relatively simple regimen of isolation, topical antisepsis, and orally administered non-absorbable antibiltics was stuidied in 18 patients. Sixteen of 21 studies were performed using portable laminar ait flow apparatus and five with isolation only. All patients became severly neutropenic but there were no major infections. Microbiological results showed effective decontamination of the skin, which was maintained without recolonization or acquisition of new organisms. The ears, nose and throat were effectively decontaminated only when the regimen was intensified. Colonization with Pseudomonas aeruginosa, a major pathogen in compromised hosts, did not occur. The propective regimen is less expensive than regimens previously desribed, is acceptable to patients, and requires no modification of existing hospital rooms. It merits further evaluation in patients with common cancers who receive intensive cytotoxic drug therapy.

Surveys conducted since 1956 on the antibiotic resistance of the Escherichia coli in faecal specimens from pigs entering Chelmsford Market have revealed that despite the implementation of the Swann Report in 1971 pigs are still an enormous reservior of tetracycline-resistant E. coli with conjugative ability.

Increasingly large amounts of E. coli resistant to streptomycin and sulphonamides were found in specimens examined in recent years unitl in 1979 the amounts present approached those of tetracycline-resistant organisms.

E. coli resistant to chloramphenicol, ampicillin, neomycin, furazolidone or spectinomycin were present, usually in low concentration, in a considerable proportion of the specimens at each yearly examination but the concentration and incidence of these organisms showed no obvious sign of increasing with time. Much of this resistance, except to furazolidone, was of the transferable type.

Until 1979 the incidence of faecal specimens containing trimethoprim-resistant E. coli was very low. It increased significantly in that year, most of the resistance being plasmid-, or possibly transposon-determined.

The result of surveys performed in a Cambridgeshire market in 1978 and 1979, which showed that a high proportion of faecal specimens contained low concentrations of trimethoprim-resistant E. coli, in general resembled those of the corresponding Chelmsford surveys, suggesting that all the Chelmsford surveys may have accurately reflected the position in the national pig herd.

The baseliiie susceptibility of the lesser bandicoot rat, Bandicota bengalensis, from Rangoon, Burma, to five anticoagulant rodenticides was established with no-choice feeding in the laboratory. The susceptibility of lesser bandicoots to the several poisons (brodifacoum, difenacoum, diphacinone, coumatetralyl, and warfarin) was such that they were offered at a 0·001 % concentration. B. bengalensis was most susceptible to brodifacoum, and in descending order, difenacoum, coumatetralyl, diphacinone and warfarin. In comparison with Rattus norvegicus on warfarin at 0·005 %, B. bengalensis proved more susceptible. Feeding tests at 0·005 % concentration indicated that a 1-day feeding on broclifacoum and difenacoum would result in complete mortality, whereas coumatetralyl and warfarin would require 4 days feeding to a 100 % kill. Brodifacoum and difenacoum are recommended at 0·002–0·005 % bait concentrations and coumatetralyl at 0 001 % concentrations for the control of B. bengalensis in the field in Rangoon. The use of any anticoagulant material in rat control should be alternated with acute toxicants to retard the possible development of anticoagulant resistance.

Inoculated orally, 16 Salmonella typhimurium strains belonging to 12 phage types varied greatly in their abilityto kill 1-day-old chickens; variation was noted even between strains of the same phage type. Fourteen strains belonging to 11 food poisoning serotypes other than S. typhimurium were practically non-lethal whenexamined in this manner. All of them were lethal by the intramuscular route but some were more so than others. Twowere more lethal by this route than one of the S. typhimurium strains that was highly lethal when given orally.With age, chickens rapidly became resistant to fatal infection with the food poisoning strains; given orally, a S.typhimurium strain killed 79 % of 1-day-old chickens but only 3 % of 2-day-old chickens. Of 2 specific poultrypathogenic strains, one, of S. gallinarum, was lethal by oral inoculation to chickens of all ages but the other, of S. pullorum, was only lethal to very young ones.

Some salmonella strains, such as those of S. infantis and S. menston, were more efficient at infecting and colonizing the alimentary tract of chickens than were the more virulent S. typhimurium strains, the S. gallinarum and S. pullorum strains and a S. cholerae-suis strain.

The continuous administration of food containing 10 mg/kg of avoparcin to groups of 28 chickens in contact with five chickens experimentally infected with a nalidixic acid-resistant (nalr) mutant of a salmonella strain strongly favoured the colonization of their alimentary tracts with salmonella organisms. Bacitracin, 10 mg/kg, either had no effect or only slightly favoured salmonella colonization and sodium arsenilate usually hindered it.

A Most Probable Number (MPN) method involving Differential Reinforced Clostridial Medium followed by streaking on Willis & Hobbs medium was com pared with direct plating of samples on Tryptose-Suiphite-Cycloserine agar with out egg yolk, and two forms of Oleandomycin-Polymyxin-Suiphadiazine-Per fringens agar, one being prepared from a commercial, dehydrated product.

With skin samples taken from chicken carcasses at different stages of processing, the three direct plating media gave similar counts of Cl. perfringens whereas results obtained with the MPN method were consistently lower.

Although counts of Cl. perfringens from various further processed products were usually < 10/g, the three plating media showed similar specificity for this organism.

All media supported good growth of reference strains of Clostridium perfringens but it was founsi that physiologically similar species, including Cl. absonum, Cl. paraperfringens and Cl. perenne also grew uninhibited in these media and produced colonies identical with those of Cl. perfringens, thus indicating the need for confirmatory tests for Cl. perfringens when examining natural samples.