This paper describes a solid-phase microtitre plate enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to equine influenza viruses. Using egg-grown influenza viruses as the antigens attached to the solid phase, crossreactions were observed between an H7N7 equine virus (designated A1) and an H3N8 equine influenza virus (designated A2) when untreated antisera were tested. Absorption of antisera with egg-grown A/Porcine/Shope/1/33 influenza virus eliminated cross-reactive antibodies so that specific detection of anti-equine influenza A1 or A2 antibodies was possible.

Examination of horse sera following vaccination with A1 and/or A2 isolates showed that antibodies were produced against antigen associated with egg allantoic fluid as well as against virus. Such antibodies were eliminated following the absorption of antisera with porcine influenza virus. Results using sera from horses with known vaccination histories confirmed that the ELISA preferentially detected antibodies homologous to the antigen attached to the solid phase and methods to evaluate the current serological state of individual horses by relating the titres of specific antibodies against equine influenza A1 and A2 isolates are shown. This ELISA provides a simple and rapid method of assessing specific antibodies from horse sera and offers advantages over the ‘routine’ HI and SRH assessments since it gives high precision, is economical of reagents and has the capacity to handle large numbers of serum samples.

Samples of milk from 1501 cows with mastitis were negative for Campylobacter jejuni. The faeces of 74 healthy Friesian cows were screened for C. jejuni: 13% of the samples were positive during the summer when the cows were on pasture, and 51% were positive in the winter when the cows were housed. Positive samples contained on average 1 × 104 campylobacters per g faeces.

It is concluded that faecal contamination rather than udder infection is the means by which campylobacters enter milk and thereby infect man.

Infection of domestic ruminants with bluetongue virus (BTV) is widespread in the Sudan but there are no records of vector species of Culicoides in that country. Therefore, light-trap collections of Culicoides for virus isolation procedures were made in the Khartoum and Um Benein areas of the Sudan during September–October 1982.

Two virus isolates were made from pools of unengorged, female Culicoides. An isolate from a pool of C. kingi (schultzei gp) is a member of the Epizootic Haemorrhagic Disease (EHD) serogroup. The other isolate from a pool of C. imicola, a known BTV vector in other parts of Africa, is type-5 BTV.

In laboratory experiments, the North American vector of BTV, C. variipennis, supported replication of both Sudanese isolates to a high titre and transmission occurred after 10 days' incubation.

This paper records the first isolation in the Sudan of arboviruses from Culicoides, with the identification of a BTV serotype and the presence of a member of the EHD (genus orbivirus, family Reoviridae) serogroup.

Bacteriocin production (P)-typing of 75 M-type 49 group-A streptococci obtained from a variety of epidemiological incidents in different countries gave no evidence of production under the usual aerobic test conditions. However, with anaerobic incubation, 28% of the strains gave a pattern of inhibitory activity against the indicator strains which was indistinguishable from that previously attributed to the bacteriocin, streptococcin A-FF22 (SA-FF22). Isolation and partial purification of the M type 49 bacteriocin (SA-M49) by freeze–thaw elution from anaerobically grown lawn cultures, followed by ammonium sulphate precipitation and Sephadex chromatography, showed the activity to be associated with a heat-stable proteinaceous molecule of molecular weight approximately 8000 – properties similar to those of SA-FF22. SA-FF22 and SA-M49 were found to have identical inhibitory spectra including immunity of the producer strains to the inhibitory activity of both the homologous and heterologous bacteriocin preparations. SA-M49 production occurred in some strains of phage subtypes II, III and provisional VI and. since it was a consistent property for all isolates from single outbreaks of infection, it provides a means of discriminating between strains of each of these three phage subtypes. There was no evidence of any increased incidence of SA-M49 production in M-type 49 strains associated with nephritic sequelae

In a preliminary seroepidemiological survey a total of 780 serum samples derived from various domestic animals of the Sudan were examined for Rift Valley fever (RVF) virus precipitating antibodies. The incidence was approximately 34·3% in sheep, 33·2% in cattle, 22%in goats, 7·9% in camels and 4% in donkeys. The findings indicated that RVF is mainly prevalent in the rich savanna areas of the south as well as the irrigated areas close to the Nile in the north.

Circumstantial evidence suggests that the detected antibodies were induced by a long-standing cryptically cycling infection and that resurgence of extensive epizootics is unlikely although limited outbreaks may occur. It is concluded that RVF virus circulates across the country in a south–north range along the Nile Valley with little or no extension to the drier lands to the east and west, and that ruminants are the primary species involved in virus maintenance. These species evidently serve as main amplifiers of infection during epizootics, but whether or not they also serve as sole virus reservoirs in inter-epizootic periods has yet to be determined.

Sera from patients with Crohn's disease more often than those from other subjects contain agglutinins against anaerobic coccoid rods, identified as Peptostreptococcus productus, Eubacterium contortum (two strains) and Coprococcus comes. The presence of antigens of the four coccoid rods in faeces of patients with Crohn's disease and healthy subjects was investigated by inoculation of rats with faecal suspensions. Antigens of the coccoid rods were detected in faeces from both patients with Crohn's disease and healthy subjects.

Rotaviruses present in products of wastewater treatment were assayed in MA 104 cells by indirect immunofluorescence. Levels in settled sewage, activated sludge and effluent were greater than 103 per litre in March and April but virus was not detected during later months. This pattern correlated with the decline in laboratory reports of human rotavirus infection.

Routine examination of the water system in an establishment where showers were used by staff after work or leisure activities revealed the presence of Legionella pneumophila. Descaling and steaming cleared the system but six months later recolonization was found to have occurred. L. pneumophila was isolated from air samples collected in the shower room whilst the shower was in operation. No clinical cases have occurred. Serological examination of those using the showers throughout the six month period together with a control group showed no evidence of infection.

Klebsiella vaccine was prepared from strains of Klebsiella aerogenes with capsular types Kl, K36, K44 and K Cross (a type which cross-reacts in vitro with sera from many klebsiella capsular types). The vaccine was extracted by dialysis and ultrafiltration from capsular material released during growth of the bacteria in a five-day batch culture.

Mice given one dose of vaccine from K1a (l·0 μg/mouse) survived lethal intraperitoneal challenge of 11/11 homologous klebsiella strains four days after vaccination; 14 days after vaccination protection against the same challenge strains had declined to 5/11 strains. Vaccines from Kla, b, c, K3G, K44 and K Cross induced homologous protection and protected mice against different ranges of heterologous klebsiella capsular types.

The protective response of the mice was greatly enhanced by administering three doses of the vaccines. Vaccines from Kl, K36, K44 and K Cross protected mice against 14/20, 11/20, 10/20 and 9/20 homologous and heterologous klebsiella challenge strains respectively.

None of the klebsiella vaccines was toxic for mice at the immunizing dose (l·0 μg/mouse). Vaccine from K36 was the most lethal, killing mice at 103 immunizing doses. The least toxic vaccine was from K44, which killed mice at 104 immunizing doses.

A study of cleaning and disinfection methods in a variety of types of catering premises has been carried out. The level of bacterial contamination of the hands and of equipment was related to cleaning methods and to the type of catering establishment. Wiping cloths were frequently contaminated with Escherichia coli, and these may be important reservoirs of bacteria for contamination of the hands of catering staff. Regular and efficient cleaning of food surfaces and equipment was found to be more important than the use of a disinfectant as part of the cleaning process. Methods for reducing the risks of cross-contamination in catering premises are discussed.

Thirty six people suffered from severe vomiting and diarrhoea 15 min to 3 h after eating vanilla slices from the same bakery. Five patients were admitted to hospital, and one developed unusual skin lesions after admission. Staphylococcus aureus was isolated in large numbers from vanilla slices of the same batch as those giving rise to symptoms, and from five faecal specimens obtained from affected persons. Bacillus cereus and Bacillus subtilis were also isolated from the slices. Unbaked custard provides an ideal environment for bacterial multiplication, especially when (as on this occasion) the ambient temperature is persistently high.

This investigation was designed to determine the prevalence of Corynebacterium suis in the preputial diverticulum of pigs of various age groups, located in different parts of the U.K., and to demonstrate whether the organism is transmissible between male pigs.

C. suis was isolated from almost 90% of 224 adult males, distributed among 25 pig units in widely separated regions of the country and in 96 % of 66 pigs aged 5–6 months originating from six different herds in East Anglia. The rate of isolation of C. suis from younger pigs depended, at least in part, on the system of husbandry practised. Thus, in one herd, A, in which young pigs were maintained in comparative isolation, none of 26 pigs aged 5–8 weeks harboured C. suis; however, in the same herd, the organism was isolated from 77 % of 64 pigs aged 9–15 weeks which were in close contact with male pigs aged up to 6 months. In another herd, B, in which individual litters were housed in the same pen from birth to 5 months of age, C. suis was isolated once from only one of 36 pigs in the age range 5–17 weeks, sampled on two occasions, with an interval of 5 weeks between each sampling. In a third herd, C, in which adult males had never been present, C. suis was not isolated from any of 26 pigs aged 4 months.

In each of two herds at the Royal Veterinary College colonization of the preputial diverticulum by C. suis was shown to have occurred by the age of 5 weeks in all of 38 pigs examined in a Large White herd and in all of 29 pigs in a Göttingen miniature pig herd.

Transmission experiments clearly demonstrated the ease and rapidity with which the preputial diverticulum became colonized with C. suis when non-infected pigs were placed in close contact with pigs which harboured the organism.

The efficacy of five rodenticides for use in bait against the golden hamster (Mesocricetus auratus Waterhouse) was investigated in the laboratory. The species proved to be resistant to warfarin (up to 0·5%) and difenacoum (0·005%), but brodifacoum (0·005%) gave complete mortality after three days' feeding. Calciferol (0·1%), though toxie, was significantly unpalatable. Zinc phosphide (5·0%) presented in a choice test for two days against unpoisoned feed gave 100% mortality, and appears to be the most suitable of these compounds for the control of M. auratus in the field.