The strength and diversity of antibody responses to infection are the basis for many of the most rapid and sensitive tests in virology, yet the need to obtain the patient's consent and co–operation, to collect blood from a vein and to separate the serum before the test often deters investigators, particularly if children are involved or if there is added risk, difficulty or cost in doing the venepuncture.

Community-based immunization is the primary method available today by which to reduce the scale of morbidity, and, in certain countries, mortality, associated with the most common childhood viral and bacterial infections. The decline in the incidences of a number of important vaccine preventable infections, such as polio, diphtheria and measles, in many countries, and the worldwide eradication of the smallpox virus, is testimony to the effectiveness of this method of control.

Thirty-seven isolates of cytomegalovirus (CMV) were obtained from a group of 20 promiscuous homosexual men, either suffering from the acquired immunodeficiency syndrome (AIDS) at the time of CMV isolation, or who developed AIDS subsequently. The isolates of CMV were characterized by the method of DNA restriction analysis. All epidemiologically unrelated strains of CMV exhibited different fragment migration patterns and no one strain appeared to be associated with AIDS or any particular disease pattern in these patients.

Sequential isolates of CMV were obtained from nine patients in the study group either from different sites at the same time or from the same site on different dates. In the case of seven of the men, viruses with minor differences in restriction profile were obtained, possiblyrepresenting sub-populations of an endogenous strain of CMV. In two of the patients, reinfection with different strains was apparent. We conclude that reinfections with CMV in AIDS patients can occur, but the isolation of strains exhibiting major differences in genome structure seen by restriction enzyme analysis was uncommon.

IgM antibodies specific for cytomegalovirus (CMV) were demonstrated in 15 (2.6%) of 575 umbilical cord sera obtained from newborns in Kuwait. Some 93% and 50% of these CMV-IgM positive cord sera displayed markedly raised (more than normal mean + 2 S.D.) content of total IgM and IgA respectively. In contrast, only 0.2 and 1.8% of the CMV-IgM negative cord sera had elevated total IgM and IgA. respectively. Rheumatoid factor (RF) was demonstrable. at concentrations of 30 IU/ml or more, in 67% of the CMV-IgM positive as compared with 3.2% of the CMV-IgM negative sera whereas interferon alpha was found in the serum of only one of these infants. These results indicate that raised total immunoglobulin. in particular IgM. concentrations and the detection of RF in cord blood are useful non-specific markers for the identification of congenital CMV infection.

A prevalence study of personnel on a Royal Naval Air Station revealed that 23·0% of 2479 personnel were carrying a meningococcus. Selected groups of personnel were subsequently swabbed monthly for a year. We have shown that it is only by repeated swabbing and the use of optimal methods including enrichment media that one can have a hope of identifying the ‘true’ carriage rate. A presumed virulent strain of Neisseria meningitidis B 15 P1·16 was repeatedly isolated from three personnel who remained well, as did their colleagues both at their work place and socially. The study served to emphasize our lack of knowledge of the virulence factors associated with N. meningitidis.

Thirty-eight isolates of the SII biotype of coagulase negative staphylococci were examined by phage typing, antibiograms, DNA and immunoblot fingerprinting. Multiple isolates were available from 5 patients with clinically proven infections and from 12 further patients who were epidemiologically distinct. Only 3 of the isolates were phage typable and antibiograms produced only 9 types. All isolates were typable by both DNA and immunoblot fingerprinting and reproducibility was excellent provided the conditions were standardized. Discrimination was better with immunoblot fingerprinting (17 types) than DNA fingerprinting (11 types). Both techniques were successful in assessing the significance of multiple isolates from a single patient.

An outbreak of infection due to Streptococcus zooepidemicus (Lancefield Group C) is described. At least 11 patients were affected and the infection was responsible for, or contributed to, the deaths of seven of these. Clinical features included septicaemia, meningitis and endocarditis. The source of infection was unpasteurized milk from a dairy herd with mild intermittent mastitis.

From July 1985 to March 1987, the occurrence of motile Aeromonas sp. in stool, food and environmental specimens was investigated to assess their pathogenic significance and to determine sources and routes of infection. A total of 9366 stool specimens were examined; Aeromonas was isolated from 11.1% of diarrhoeal stools and 2.2% of normal stools (P 0.001). Aeromonas counts in food specimens, which included minced beef, pork and chicken, seafood and various vegetables and their products, were unexpectedly high suggesting that infection might be food–borne rather than water–borne. About 70% of the isolates from meat products were A. hydrophila and A. sobria, while A. Caviae was the most common in sea–fish, vegetables and their products. Most A. hydrophila and A. sobria strains produced haemolysin, but haemagglutinin was found more frequently in A. Sobria.

Isolates of adenovirus types 1 and 2, obtained from 11 infants with prolonged faecal excretion (up to 515 days), were compared by DNA restriction analysis with seven standard endonucleases which recognize hexanucleotides and two additional endonucleases which recognize tetranucleotides. In all instances identical genome types were identified in isolates obtained early and late after infection. Our interpretation of these data is that a chronic persistent infection occurred in these children. and not a reinfection with the same serotype.

Recovery of Yersinia enterocolitica and related strains from faecal samples enriched in 1% buffered peptone water (pH 7·2) and incubated at 4 °C for 17–21 days was compared with recovery from 1% peptone water buffered to pH 8·0 and incubation over the temperature range 4–26°C. Best recovery was obtained by use of the alkaline medium incubated at 9°C. Greatest recovery was obtained after incubation for 10–14 days, but most strains (> 75%) were recovered after 1 week.

A total of 201 new cases of tuberculosis due to bovine tubercle bacilli was confirmed in South–East England between 1977 and 1987 inclusive. This represents about 1% of all cases of tuberculosis in this region. Most cases occurred amongst older individuals of indigenous white British origin, although some younger patients of Southern European and Indian subcontinent ethnic origin were also diagnosed. The lung was the most frequent site of disease, followed by the genitor–urinary tract. In view of the known risk of transmission of disease from man to cattle via the respiratory and urinary tracts, continued surveillance of this relatively uncommon form of tuberculosis is still indicated.

Information was collected on confirmed outbreaks of western equine encephalitis (WEE) in North America east of the Rockies for 1981 and 1983 (epidemic years) and 1980 and 1982 (non-epidemic years). The initial pattern of outbreaks in Manitoba, Minnesota and North Dakota was determined for each year. Backward (and in some instances forward) wind trajectories were computed for each day 4–15 days (incubation period) before the initial outbreaks of WEE in a given area of province or state.

Captive, healthy, adult badgers have blood containing haemoglobin at 13·3 g/dl, and 8·4×1012/l red cells with an MCV of 46·2 f1 and an MCH of 15·6 pg. They have 5·1×109 white cells/1 of which 3·29×109 are polymorphs, 1·49×109 are lymphocytes, 0·26×109 are monocytes, 0·07×109 are eosinophils and 0·01×109 are basophils. These values are somewhat less in adult animals just trapped from the wild, and are lower still in wild cubs.

Changes associated with tuberculosis are a rise, and then a fall in red blood count and white blood count, an increase in the proportion of polymorphs and momocytes and a fall in lymphocytes late in the disease. This picture is similar to that seen in widespread, disseminated, tuberculin negative, tuberculosis in humans, a type of disease similar to that occurring in many badgers.

BCG vaccination of badgers did not produce any measurable change in the blood picture.

Rabbit polyclonal hyperimmune antibodies to Yersinia pestis, and a mouse monoclonal antibody against the capsular antigen fraction 1 (F1) were compared in immunofluorescence (IF) tests. Fluorescent antibody conjugates were prepared from polyclonal antisera to four F1 positive Y. pestis strains; the conjugated antibody to strain A1122 gave the strongest IF staining of F1 positive and F1 negative Y. pestis strains. Indirect assays were rejected in favour of direct assays utilizing polyclonal and monoclonal reagents because the increased background staining reduced the effective contrast of bacterial visualisation. Polyclonal conjugates gave fairly homogeneous staining of Y. pestis bacterial populations, but in monoclonal assays a skew distribution of fluorescence intensity was observed, the majority of bacteria being poorly stained. The proportion of cells stained well by the monoclonal sufficed for easy identification of Y. pestis of the F1 positive phenotype however, and staining was not affected by washing the bacteria or treating them with formaldehyde. Y. pestis strains of the F1 positive genotype reacted with the monoclonal if bacteria were grown at 37 °C but not if the growth temperature was reduced to 25°C thus preventing capsule production. The polyclonal conjugate reacted with bacteria of these strains that had been grown at either temperature. Strains of F1 negative genotype grown at either temperature. Strains of F1 negative genotype grown at either temperature reacted with the polyclonal conjugate but not with the monoclonal. Cross reactions between the polyclonal reagents and Y. enterocolitica biovar 2, serovar O 8 could not be removed by selective absorption; however, the monoclonal antibody gave no cross reaction.

The F1 phenotypic status of bacterial preparations was verified by ELISA measurement of the fraction 1 antigen concentration. Antigen levels for F1 positive and F1 negative phenotypes differed by about three logs for suspensions of Y. pestis harvested from solid media.

The polyclonal and monoclonal direct IF tests applied to spleen and blood smears of laboratory mice infected with Y. pestis were able to differentiate between lethal infection with an F1 positive strain carrying all four classical virulence determinants, an F1 positive vaccine strain, and an F1 negative strain.

Three hundred and seventy-six patients attending their general practitioner with cutaneous warts at five health centres in Northern Ireland were screened for human papilloma virus (HPV) types 1 and 2 IgM antibody using an indirect immunofluorescence test. Eighty-eight (23·4%) patients were positive for HPV type 1 IgM and 156 (41·5%) for HPV type 2 IgM. HPV 1 IgM antibody was significantly more likely to be associated with plantar warts than warts elsewhere (P 0·0001). HPV 2 IgM was present in 45 (34·1%) patients with plantar warts and 99 (45·6%) patients with warts at other sites (P=0·1). Evidence of multiple infection by HPV types 1 and 2 was demonstrated by the finding of HPV 1 and 2 IgM antibodies in the sera of 16 (4·3%). HPV 4 was found in only 1 out of 30 biopsies and HPV 4 IgM was undetectable in 50 randomly chosen sera.

African swine fever (ASF) has been reported in the Eastern Province of Zambia since 1912 and is now considered to be enzootic there. A survey of the distribution of ASF virus in Zambia was carried out by virus isolation from Ornithodoros moubata ticks collected from animal burrows in National Parks and Game Management Areas in northern, eastern, central and southern Zambia. ASF virus was isolated from ticks in all areas examined. The prevalence of infection in O. moubata was between 0·4% in South Luangwa National Park and 5·1% in Livingstone Game Park and mean infectious virus titres ranged from 103–4 HAD50/tick in Kakumbe Game Management Area to 105·9 HAD50/tick in Chunga and Nalusanga Game Management Areas. The prevalence of infection in adult ticks was between 4·7% and 5·3% in all areas examined except Sumbu National Park and Livingstone Game Park, where the prevalence was 15·1% and 13·2% respectively in adult ticks. The ratio of infected females to males for all the infected adult ticks in all areas of Zambia was 3·2:1.

Food poisoning due to Salmonella typhimurium phage type 141 was unusual inthe Sheffield area before 1984. The sudden increase in incidence of this phage type during 1984 and 1985, and its causative role in several small outbreaks in this period have been investigated. Epidemiological and laboratory investigations suggested that hens' eggs were the most likely source of S. typhimurium phage type 141.

A case-controlled study of the incidence of heat-labile enterotoxin-producing Escherichia coli (LT+ETEC) and other enteric pathogens in travellers returning to the Sheffield area was conducted from May 1984 to April 1986. LT+ETEC were found in 35 (5.8%) of 600 travellers to developed countries (mainly popular Mediterranean holiday resorts), 36 (11.3%) of 320 travellers to less-developed countries, and 11 (0.9%) of 1282 control patients whose illness was not associated with recent travel abroad. A seasonal peak of LT+ETEC infection was observed only in travellers to developed countries, with infections being significantly commoner in August to October. There was no significant deviation from expected age/sex distribution of LT+ETEC infection. Strains of LT+ETEC from travellers produced more toxin than strains from control patients, strains from travellers to less-developed countries producing most of all.

Gastroenteritis due to Salmonella montevideo occurred amongst guests attending two social functions held within 24 h, food for both having been provided by the same catering firm. Salmon was the most likely vehicle of infection in each case, although cross-contamination of other foods occurred. There were no deaths; four patients were admitted to hospital, one of whom underwent appendicectomy.

A review of salmon-associated food-poisoning outbreaks suggests that fresh salmon is an infrequent cause of food poisoning in the United Kingdom. The two outbreaks described here resulted from a failure of simple kitchen hygiene measures at a time of high ambient temperatures. Some current cooking instructions for salmon are inadequate.

The first recognized outbreak of haemorrhagic colitis due to Escherichia coli O 157. H7 in the United Kingdom affected at least 24 persons living in East Anglia over a 2-week period. Theillnesses were characterized by severe abdominal pain and bloody diarrhoea of short duration. Eleven patients were admitted to hospital and there was one death. Patients were mainly adult women who had not eaten out of the home in the 2 weeks before onset. Unlike previously reported outbreaks hamburgers were not the vehicle of infection, and a case-control study suggested that handling vegetables, and particularly potatoes, was the important risk factor.