Drinking water is a recognized mode of transmission of various parasitic and bacterial infections and high prevalence rates of water-borne infection have been found during past studies in rural areas of the Nile Delta (Farag et al. 1979; Khairy. Barakat & Omar, 1978).

Whilst the major danger associated with drinking water is that it may be contaminated with sewage or human excreta, the danger of pollution from animals must not be overlooked. Outbreaks of infection from drinking water are frequently reported (Melnick & Gerba, 1979) and high prevalence rates of diarrhoeal diseases have been found in the Nile Delta (Sallam et al. unpublished data). The supply of potable water is a critically urgent national problem and is of especial importance to communities which must rely on poorly designed supply systems and which lack even the minimum quality control services.

Twelve antimicrobial drugs were studied for their effect on the endogenous aerobic potentially pathogenic bacteria (Enterobacteriaceae, Streptococcus faecalis) in the intestines and on the colonization resistance (CR) of the digestive tract. Three subclasses of antimicrobial drugs could be recognized: (1) those which suppress the CR following low oral doses (rifamycin, penicillin V, cloxacillin, fenethicillin); (2) those in which the CR is suppressed only following relatively high oral doses (amoxycillin); and (3) those in which no obvious suppression of the CR was noticed even following substantial oral doses (nalidixic acid, cinoxacin, co-trimoxazole, oral cephalosporins, piv-mecillinam and doxycyclin). Some of the drugs in the third category were found to suppress endogenous Enterobacteriaceae (nalidixic acid, co-trimoxazole, piv-mecillinam and doxycyclin) and S. faecalis (doxycyclin) at dose levels at which they did not decrease CR.

The results of typing all group A streptococci isolated in one laboratory in 5 years were reviewed to see if the collected information showed epidemiological patterns. The great majority of the 5858 streptococci typed came from patients seen in general practice: 72% from throat swabs and 11 % from skin lesions. Eight types, M types 1, 2, 3, 4, 6, 12, 22 and type 28 R accounted for 65% of strains. These eight types had different patterns: types 2 and 6 caused small circumscribed outbreaks and were uncommon between epidemics; types 3, 4 and 12 caused larger, wider epidemics, whereas types 1, 22 and 28 R had a more stable pattern. Type 4 was more commonly resistant to tetracycline than most other types, a finding which affected the apparent incidence of tetracycline resistance in group A streptococci. Streptococci from superficial sites were more likely to have serum opacity factor and to lack a detectable M-antigen than strains isolated from the throat. Routine typing of streptococci helped to detect outbreaks of infection in special groups. It is concluded that regular streptococcal typing should be continued in some places.

The frequency distribution is presented of the Vi-phage types of Salmonella typhi and of the phage types of S. paratyphi A and S. paratyphi B, examined by the National Centres represented in the IFEPT from 1970 to 1974. The most common types encountered in this international study were A and E1 (= E1 a), as has been previously observed. There was, however, a wide range of types, many of which are characteristic of particular geographical zones. The occurrence of such types out of their habitual context indicates their ‘exotic’ origin, providing a useful clue to their probable source.

Plasmid-mediated chloramphenicol resistance appeared in epidemic typhoid fever for the first time during this period. It occurred in Mexico, India, Vietnam and Thailand, and has assumed important proportions. All the plasmids concerned belonged to compatibility group H 1. The study of this phenomenon continues, and the findings will appear in future reports.

An immunosorbent assay using solid-phase attachment of red cells (SPARC) was used for the detection of rubella-specific IgM. The method is described and the results compared with those obtained by the IgM antibody capture radioimmunoassay (MACRIA). One hundred and ninety-nine sera were investigated for the presence of rubella-specific IgM and only one discrepant result occurred, namely a false positive obtained by MACRIA in a patient with infectious mononucleosis. Rheumatoid factor, heterophile antibody, and rubella-specific IgG did not interfere with the results obtained by the SPARC technique. Advantages of the SPARC technique include the ease and lack of expense of testing large numbers of sera, the small volume of sample required and the fact that pretreatment of serum is not necessary.

The development of the bacterial flora of neonates with congenital abnormalities of the gastro-intestinal tract was studied in 31 infants during the first 10 days of life. Specimens were collected from the umbilicus, mouth and gastro-intestinal tract on the pre-operative day, at operation and on post-operative days 1, 2, 3, 5, 7 and 10. Bacteria were isolated semi-quantitatively on a variety of plain and selective media and identified by conventional methods.

Staphylococcus albus was the predominant species isolated from the umbilicus; it was recovered from 24 of the 31 babies. The viridans group of streptococci and Streptococcus salivarius were the commonest species isolated from the mouth; there were no differences between the babies with different abnormalities and treatment with antibiotics had no effect on the bacterial flora. Ten babies were colonized by each species on the pre-operative day, and 25 and 19 respectively by the tenth post-operative day. Anaerobic gram-positive cocci were the predominant oral anaerobes. Bacteria were not isolated from the rectal swabs of babies with tracheo-oesophageal fistula (TOF) or small bowel atresia on the pre-operative days. Post-operatively the predominant faecal isolates from babies with TOF were Str. faecalis, Escherichia coli and Clostridium perfringens. About 80% of the babies with small bowel atresia were colonized by Str. faecalis and Bacteroides vulgatus, 60% each by E. coli, Klebsiella aerogenes and Str. faecium. The five babies with necrotizing enterocolitis were colonized by Str. faecalis, E. coli, Cl. perfringens and Cl. difficile; Bacteroides spp. were not recovered from any of them. The commonest facultative species recovered from babies with large bowel obstruction were Str. faecalis and E. coli. B. vulgatus, Cl. perfringens and Bifidobacterium spp. were the commonest anaerobes and anaerobes outnumbered aerobes. No significant isolates were recovered from the wound swabs and none of the babies developed post-surgical sepsis.

Salmonella mbandaka was isolated from cattle on three dairy farms. The duration of infection was less than four weeks and none of the animals became clinically ill. The animals had all consumed a diet containing a vegetable fat supplement contaminated with S. mbandaka and this was shown to be the source of the infections. It is significant that a feed containing purely vegetable components was incriminated.

Surveillance of influenza in England and Wales is made by monitoring weekly data. Principal indices are deaths, sickness-benefit claims (SBC), laboratory reports and observations from general practitioners (GPs). The 12 winters 1968/9 to 1979/80 have been studied to see which indices best described size and timing of influenza epidemics. A method of plotting the data (called cusums) is suggested which makes it easier to see the effect of small epidemics.

Cusums for GP statistics and respiratory deaths were found to be the most helpful indices for describing both size and timing of the epidemics, followed by total deaths and SBC, which were less specific to influenza, and influenza deaths, which lagged behind other indices. Deaths certified as pneumonia have been increasing over these years, whereas bronchitis deaths have been decreasing and these indices should not be used separately for monitoring.

The laboratory reporting system is important. It confirms the presence of influenza virus in the community and indicates prevalent strains. Because it is a voluntary system with no defined population base the reports are not reliable numerically for estimating relative size of epidemics or for developing cusums.

Cusum plots were unanimous in describing the winter of 1980/1 as one of little influenza activity.

Attempts were made to isolate viruses from babies' stools that contained adenoviruses detected by electron microscopy. One hundred and fifty-nine specimens from 71 children were studied and adenoviruses of established serotypes were isolated from 81 stools. Serial stool samples containing adenovirus particles were obtained from 35 children, and prolonged shedding of recognized serotypes was common. Simultaneous and sequential infections by different serotypes were also observed. Thirty-six children shed adenoviruses that could not be isolated using cell cultures normally used to detect adenoviruses, and nine of these children also shed adenoviruses of established serotypes. Passage in Chang conjunctival cell cultures allowed characterization of fastidious adenoviruses from 14 children as members of a previously unrecognized serotype.

Two Bordetella pertussis antigen preparations, outer membrane protein (OMP) and filamentous haemagglutinin (FHA), and a standard vaccine were used to immunize rabbits, and the effects on nasopharyngeal colonization by the organism were determined. Antibodies were measured in serum and in nasal washes by ELISA before and after challenge of the rabbits with 106 bacteria of strain M2. Recoveries of B. pertussis in nasal washes were used to assess colonization, which in controls persisted for at least 65 days. Some rabbits of all the immunized groups showed enhanced clearance, but there was no correlation between the elimination of B. pertussis and serum antibodies to OMP, FHA, lipopolysaccharide, lymphocytosis-promoting factor or agglutinogen 3. In contrast, nasal IgA antibody to FHA showed significant inverse correlation with bacterial persistence. Such antibody was induced by the OMP preparation as well as by FHA, but to different extents depending on the immunization schedule and adjuvant used.

A selective membrane filtration medium is described for use in the rapid assessment of water quality in tropical countries where the incidence of faecal coliforms other than E. coli presents problems in the interpretation of results. The medium gives comparable results to MPN values obtained in the multiple tube dilution test using modified Gray's glutamate medium, and to membrane filtration counts obtained using M-FC broth and membrane-enriched Teepol broth, whilst differentiation of E. coli is enhanced.

Lumpy skin disease virus strains isolated in Kenya over a period of some 20 years have proved to be serologically identical. They were indistinguishable by indirect fluorescent antibody and serum neutralization tests from the South African Neethling and West African serotypes. These two serological methods proved of value in studying the antibody responses to infection.

While epizootic spread of LSD has occurred in Kenya, most cases are of a sporadic nature and are thought to be the result of accidental contacts with a maintenance cycle. There is evidence of antibody to LSD in the African buffalo (Syncerus coffer) in those areas where LSD is considered to be enzootic in Kenya, and also in small numbers of domestic cattle. No buffalo or bovine sera contained antibody to cowpox virus. An area enzootic for LSD is proposed and it is suggested that the maintenance cycle involves the buffalo. No antibody was found in the other wild ruminant species examined.

The production of enterotoxin A and B by strains of Staphylococcus aureus isolated from nasal swabs of healthy carriers, from lesions of hospital patients and from foods unconnected with outbreaks of food-poisoning was investigated. Sixty-six strains of S. aureus were obtained from human beings, two produced enterotoxin A, 45 produced enterotoxin B. seven produced enterotoxins A + B. Thirty-six strains were isolated from 111 samples of food, one produced enterotoxin A, 16 produced enterotoxin B. The relative incidence of A, B and A + B enterotoxigenicity was assessed.

Dispersal of non-sporeforming anaerobic bacteria was studied. Skin samples were taken from the subjects, and dispersal from different parts of the body was examined.

The number of anaerobic bacteria dispersed was not correlated to their density on the surface of skin area exposed. The highest density of anaerobic bacteria on the skin was found in the face and upper trunk, but the highest yield of anaerobic bacteria dispersed came from the lower trunk.

The dominant anaerobic bacteria dispersed were Propionibacterium acnes, but Propionibacterium avidum, Propionibacterium granulosum and Gram-positive cocci were also isolated from the dispersal samples. Peptococcus magnus was the most common coccus isolated. For the less frequently isolated bacteria, the best correlation was found between the perineal flora and airborne bacteria.

A comparison was also made of bacterial dispersal by naked and dressed subjects. The dispersal of both aerobic and anaerobic bacteria was higher when the subjects were dressed in conventional operating theatre cotton clothing than when they were naked.

The increased dispersal of anaerobic bacteria when the subjects were dressed was mainly due to increased dispersal of Propionibacterium sp.

The susceptibility to antimicrobial agents of 569 salmonella isolates collected in 1977–8 from patients in hospitals in Rome was tested. Fifty-nine per cent of all isolates were resistant to one or more antimicrobials. Resistance was most common to sulphathiazole, tetracycline, streptomycin, whereas colistin, gentamicin, tobramycin, trimethoprim-sulphamethoxazole and nalidixic acid were the most active in vitro.

Multiple resistance was most frequently found in strains of Salmonella wien and S. typhimurium (94% and 38% respectively).

A significant change in the resistance pattern of S. wien was observed between 1977 and 1978, with a significant increase of susceptibility to some antimicrobials in 1978.

Twenty-one R-plasmids transmissible to E. coli K12 were derived from 46 resistant strains of S. typhimurum.

In May 1980 an extensive outbreak of gastroenteritis occurred in a private school in the city of Rio de Janeiro. Examination of faeces and paired sera showed that this outbreak was caused by both rotavirus and a virulent strain of Shigella sonnei. In the first 19 stool samples collected seven (37%) had rotavirus only, six (32%) had Sh. sonnei only, while four (21 %) had both agents. Examination of the second and third stool collections revealed only the presence of Sh. sonnei. The 18 paired sera showed seroconversion for rotavirus in four cases (22%) and in seven cases (39 %) for Sh. sonnei. The overall attack rate of the disease was approximately 75 %, the nursery and kindergarten having higher attack rates. Students in all grades became sick at the same time, and the unimodal curve of the onset dates of symptoms indicates a common source outbreak. Evidence suggested a contaminated water supply.

Groups of pigs were brought to an abattoir by truck and approximately 25 were killed on each of the next 3 days.

While the pigs were in lairage they were given water but were not fed. After slaughter the caecal contents of all pigs were cultured to detect Salmonella spp. The organism was isolated from 70% of 145 pigs killed after 1 day in lairage, 49% of 143 pigs that had been in lairage for 2 days and 41% of 135 pigs that had been held for 3 days.

The laboratory surveillance of influenza in the UK has continued to demonstrate the regularity of influenza outbreaks each winter even in the absence of increase in the other indices which reflect the morbidity and mortality associated with influenza.

The period of five years from 1976 to 1981 has seen the appearance of a second sub-type of influenza A with the return of the historic H1N1 virus; and the continued circulation of H3N2 concurrently with H1N1 virus. Variants of both these influenza A viruses have been demonstrated as well as further changes in the strains of influenza B virus isolated during this time.

Strains of Escherichia coli were isolated from laparotomy specimens from Chinese patients with recurrent pyogenic cholangitis in Hong Kong. A large variety of serotypes were found. Several sites were sampled in each patient. While only one serotype was normally isolated from one site, different sites often yielded different serotypes in the same patient. Generally the ‘O’ types found did not correspond to those found in the faeces of the Hong Kong Chinese population.