Thirty-three of 72 heroin addicts attending a recognized clinic for drug addition had a history of jaundice, but in only five was the serum positive for hepatitis-associated antigen (HAA) when examined by immunodiffusion, immunoelectro-osmophoresis and complement fixation. Two of these were repeatedly positive over an 8–12 month follow-up period and liver biopsy showed chronic persistent hepatitis. A third later developed acute hepatitis. A study of the injection habits suggested that the present low incidence of HAA and the decrease in number of cases with jaundice was probably related to the provision of free disposable syringes by the clinic since it was opened in 1968.

Cationic proteins isolated from the cells in bulk milk samples were shown to inhibit the growth of two pathogenic strains of staphylococci and also Streptococcus agalactiae S 13. Polyacrylamide gel disk electrophoresis studies on these proteins revealed the presence of at least 9 components some of which had isoelectric pH's between 7·0 and 9·0. Trace amounts of the isolated protein had isoelectric pH's greater than 9·0. Staphylococci incubated with milk-cell cationic proteins absorbed the protein, thereby allowing the organism to be stained with the anionic dye Fast Green FCF. Protein-treated staphylococci in isotonic solutions autoagglutinated. This autoagglutination was more marked in hypo- and hypertonic solutions. Lysozyme was not demonstrated in the isolated protein fractions in assays involving incubation with Micrococcus lysodeikticus for 90 min. The antimicrobial activity of the cationic proteins isolated from the bulk milk samples was not destroyed after heating to temperatures up to 70° C for 30 min., whereas at higher temperatures the activity diminished and was almost completely lost at 100° C.

Neutralization tests with a strain (BA) of Allerton-type herpes virus, derived from a buffalo (Syncenis caffer) were carried out on 924 sera from 17 species of E. African game animals and on cattle sera from Tanzania (2001), Kenya (792) and Uganda (410).

Buffalo populations throughout E. Africa showed a very high rate of infection, with all animals over 2 years of age serologically positive. Antibody was present in some giraffe, waterbuck and hippopotamus sera and, less frequently, in impala, eland, bushbuck and oryx. Data are provided on the titres of positive samples; the mean titre of buffalo sera increased with age.

Cattle in many localities of N. Tanzania and S. Kenya showed a very high rate of infection, 85–95% of sera from animals more than 2-years old containing antibody; the titres recorded were lower than those in buffaloes. Very high infection rates were also found in Karamoja and Teso (Uganda) and also in some other areas of Kenya, whilst a considerably lower incidence of infection was detected in W. Nile Province of Uganda and in central Tanzania. Differences in infection rates may have been related to herd size and husbandry practices.

It was shown that a wave of infection was probably spreading through cattle in N. Tanzania at about the same time as an outbreak of disease occurred in buffaloes and it is suggested that virus transmission may have been by biting flies.

No clinical signs attributable to the virus were reported in cattle but mouth lesions similar to those recorded in buffaloes, or nasal lesions, could have passed undetected. Allerton-type virus probably produces a range of clinical syndromes in cattle, closely resembling those associated with some herpes viruses in primates but infection is seldom related in the field to either pseudo-lumpy skin disease, mammillitis or stomatitis.

After subcutaneous vaccination of rubella sero-negative children with Wistar RA 27/3 rubella vaccine, haemagglutination-inhibiting antibody titres were compared in sera taken 46 days and 2 years after vaccination. Antibody titres were well maintained in the absence of any known exposure to natural infection.

Scotland and Ireland have the highest death rates from multiple sclerosis and high rates are recorded in an area extending south-eastward from Britain through central Europe. The rates tend to diminish with rising latitude and longitude. In England and Wales the county boroughs with notably high rates during 1958–67 were mostly textile towns with cotton and wool mills, situated in the area recording the lowest average levels of sunshine. In the London area mortality from multiple sclerosis was high in those western boroughs and adjacent counties most exposed to the noise of aircraft using the airports of London. The geographical pattern in England suggests that noise and vibration of particular kinds may be a factor in causation along with a climatic factor, but this hypothesis is speculative until further evidence is found to support it.

Thirty-seven volunteers were inoculated intranasally with living attenuated influenza A 2 viruses. Rising titres of circulating antineuraminidase (AN) were detected in 14 of 17 infected volunteers. AN was also found in nasal secretions. Statistical analysis showed that there was a correlation between the titres of haemagglutination-inhibituig antibody (HI) and AN in nasal washings, and between AN in blood and washings. Resistance to infection could be predicted from antibody titres in 29 of 37 volunteers and blood AN alone predicted the outcome of 25 volunteers.

Individually caged house mice (Mus m. musculus) were fed 0·025% warfarin (3(2-acetyl-l-phenylethyl)-4-hydroxycoumarin) or 0·025% chlorophacinone (2-(l-(p-chlorophenyl)-l-phenyl) acetyl-l,3-indandione) for periods varying from 1 to 21 days. In all, 320 mice, 160 of each sex, were tested.

A significant difference was found between the mortalities obtained by the two compounds. In feeding periods varying from 1–5 days chlorophacinone produced a mortality of 60–85 % and warfarin only 5–75 %. Five per cent, however, did survive 21 days feeding on each compound.

A great variation in the susceptibility of individual mice was established for chlorophacinone as well as for warfarin.

Organ cultures prepared from 15 different organs obtained from 43 fetuses were consistently found to support the growth of rubella virus, irrespective of the gestational age of the fetus or the strain of rubella virus inoculated. Although rubella virus replicated in fetal lenses, adult lenses did not support the growth of rubella virus. Organs obtained from four fetuses between 8 and 17 weeks gestational age produced similar titres of an inhibitor which had the characteristics of interferon. The use of Trowell T8 medium and incubation in a mixture of 5% CO2 in oxygen provided the most suitable conditions for the maintenance of most organ cultures. Under these circumstances it was possible to obtain adequate histological preparations from these organs, but light microscopy studies revealed no significant differences in sections of rubella inoculated and control organ cultures.

Serum cholesterol in rabbits was elevated, by intravenous inoculation of 20 % Tween 80, to amounts thought to have been sufficient to support growth of Mycoplasma gallisepticum when 20 % of such serum was added to rabbit infusion broth.

However, better growth of the organism was obtained with a supplement of 5 % rabbit serum and commercial cholesterol. Investigation showed that normal rabbit serum may be inhibitory, which would explain these findings. The commercial cholesterol was not antigenic.

Mice vaccinated with a live attenuated strain of Salmonella dublin were protected against heavy challenge infections of S. dublin, S. typhimurium, S. choleraesuis and S. anatum. Oral and subcutaneous vaccination were equally effective. When day-old chicks were orally vaccinated and subsequently challenged with S. typhimurium, the growth of the challenge organism was considerably reduced or eliminated from the livers of the vaccinated chicks whereas most of the non-vaccinated were heavily infected. Field trials with vaccinated day-old chicks showed that they suffered no setbacks in growth, stress, loss of appetite or adverse side effects.

Hysterectomy-produced, colostrum-deprived (HPCD) pigs and naturally born, enzootic-pneumonia-free (EPF) pigs were compared with respect to their susceptibility to two strains of enzootic pneumonia induced by intranasal inoculation of suspensions of ground pneumonic tissue. All but one of the HPCD pigs developed enzootic pneumonia, whereas the EPF pigs commonly failed to develop the disease; secondly, the pneumonic lesions were more extensive in the HPCD pigs.

When the dose of inoculum was increased in EPF pigs, the resulting pneumonic areas were larger.

In a small, in-contact experiment the disease was also more readily transmitted to HPCD pigs than to EPF pigs.

This study of 724 13-year-old schoolgirls in the County Borough of Reading showed that approximately 25% were susceptible to rubella. 96·1% of the 129 seronegative girls and significant numbers of girls with low rubella HAI antibody titres responded to subcutaneous vaccination with Wistar RA. 27/3 rubella vaccine. The incidence of most reactions after vaccination was similar in those who responded to vaccine and those who were initially immune but did not develop rising antibody titres, but rash, lymphadenopathy and headache occurred significantly more frequently in the susceptible group.

This study describes the results of attempts to grow viruses from per-nasal swabs taken from 136 children with clinical pertussis.

Altogether 37 strains of a variety of different viruses were isolated. Adenovirus was the most frequent, making up 30 % of the total. Besides these, herpes simplex, measles, influenza A2, influenza B, mumps, poliovirus and respiratory syncytial virus were detected.

Bordetella pertussis was isolated from 22 % of the cases.

It appears that a pertussis-like syndrome can be caused by many agents besides Bord. pertussis and an accurate diagnosis requires laboratory confirmation.

The efficacy of horizontal and vertical laminar flow units (equipped with high-efficiency air niters) in the prevention of cross-contamination between cages and of contamination from outside has been demonstrated. With germ-free mice and using germ-free standard techniques for sterilization and for the transfer of germ-free mice into the cabinets via a standard entry lock, it was found that during an observation period of 2 weeks the animals remain ‘negative’. Other experiments were performed with equally good results in cabinets equipped with a hinged flap, closing 95 % of the open front side. When the flap was closed the air flow could be reduced accordingly, thus reducing the noise level and the risk of dehydration.

Experiments made with germ-free mice in a ‘down-flow unit’ were also invariably good.

In another type of experiment, cages with conventional mice were placed in the cabinets between cages with germ-free animals at varying distances. If all animals were maintained on wire mesh (to minimize the aerosol production of dust) and if the ‘conventional’ cages were at a distance of 10 cm. from ‘germ-free cages’ the latter remained bacteria-free during test periods of one week.

The use of ‘laminar flow isolators’ for the isolation of human patients is mentioned.

Human infections with Salmonella saintpaul have become more frequent in New Zealand in recent years. Most cases now occur in Otago. It is shown that wild lizards in Otago, particularly the common skink (Leiolopisma zelandica), carry S. saintpaul and that most if not all human outbreaks of this salmonella serotype are associated with either lizards or lizard infested areas. So far as is known this is the first report incriminating lizards as the probable cause of human salmonellosis.

Influenza C virus antigen could be detected by immunofluorescence in chick amniotic epithelium 4 hr. after inoculation with undiluted amniotic fluid. Antigen could be detected in the nucleus of rhesus monkey kidney tissue cultures 10 hr. after infection. Only cytoplasmic fluorescence was observed 17–21 hr. after infection.

The pattern of replication was similar to that reported for group I myxoviruses, indicating that the virus is correctly classified as an influenza virus.

Mycoplasma gallisepticum antigens were prepared from organisms cultured in broth medium with glucose. The influence of period of growth, pH of the medium and duration of incubation at low pH (5·0) on the sensitivity of these antigens was determined in certain tests. The most sensitive antigen for the serum plate test was harvested after no more than 8 hr. incubation at pH 5·0. Sensitivity in serum plate, haemagglutination and gel diffusion tests was impaired if organisms were incubated at pH 5·0 for long periods. Antigens prepared from buffered broth medium were found to be at least as sensitive as those from unbuffered medium for the haemagglutination and gel precipitation tests, but considerably less so for the serum plate test.

Eight epidemics of respiratory disease have been observed among islanders of Tristan da Cunha. They seem to be initiated by the arrival of ships and transmission seemed to occur as a result of close human contact but could not always be traced. Islanders suffered from less colds than those in less isolated communities.

Between October 1968 and February 1970, 30 strains of cytomegalovirus were isolated from the urine of children admitted to hospitals in Lyon. Three groups of children up to the age of 14 years have been investigated.

The first group consisted of 304 newborns and infants up to the age of 1 year; cytomegalovirus was grown from five of these (1·6%). Among these five children, two had cerebral disorders. None of them had ever shown any sign of typical CMV infection.

The second group comprised 102 children between the ages of 1 and 14 years, from a special service for neurological and mental diseases. Cytomegalovirus was grown from 19 (18·6%).

The third group was 27 children also between 1 and 14 years of age, admitted to hospital for miscellaneous diseases excluding cerebral disorders; cytomegalovirus was grown from six (22·2%).

It appears that cytomegalovirus has a very low incidence in neonatal disease. The virus spreads at a higher rate in children 1–14 years old. No difference has so far been shown in the excretion rates of two groups of children, one with cerebral disorders and one with other diseases, but the number of children in the last group is too small to allow definite conclusions to be drawn.

The effect of oral administration of antibiotics on the intestinal flora of conventional mice and their resistance to colonization by orally introduced Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa was studied. Colonization resistance (CR) was expressed as the log of the oral bacterial dose followed by a persistent take in 50 % of the contaminated animals. The intestinal flora was virtually eliminated by the antibiotics and this elimination was accompanied by a precipitous fall of CR. CR gradually returned to normal values during the period of repopulation of the intestinal tract by the organisms surviving the treatment. Antibiotic treatment resulted in the disappearance of Enterobacteriaceae, enterococci, staphylococci and yeasts and, under appropriate housing conditions, the animals remained free of these organisms indefinitely. Germ-free mice contaminated with the intestinal flora of an antibiotic-treated animal and their offspring housed in a germ-free isolator showed high values of CR. Their intestinal flora consisted of anaerobic bacteria only. Apparently, these anaerobes are responsible for CR in these and in conventional mice.