Measles surveillance data in Blantyre, Malawi were reviewed for 1996–8 to describe the epidemiology of infection and to estimate vaccine efficacy (VE) by the screening method. A total of 674 measles cases were reported to the Blantyre District Health Office during this period. Age distribution showed that 108 (16.1%) of the cases were aged less than 1 year. The median age was 5 years. Eighty percent of the cases between 1 and 19 years had been previously vaccinated. VE was 68.6% (95% CI, 52.7–79.2) for children 12–23 months of age and 67.3% (95% CI, 48.3–79.3) for infants 9–11 months of age. Reasons for this low vaccine efficacy are discussed. Previous vaccination history was negatively associated with the risk for developing cough during measles infection (odds ratio (OR), 0.30; 95% CI, 0.09–0.91), diarrhoea (OR, 0.64; CI, 0.44–0.95) and pneumonia (OR, 0.40; CI, 0.25–0.62). Logistic regression analysis showed that pneumonia in adults was negatively associated with vaccination history. The passive surveillance system for measles in Malawi was useful to describe the epidemiology of measles.

Since the original definition of the coli-aerogenes group of organisms by MacConkey (1905,1909), research has been continually directed in an endeavour to find a more rapid and definite distinction between its respective members.

In general, for the purposes of water analysis, the conform organisms can be divided into two main groups: faecal coli, of which Bact. colitype I can be considered the typical member, and the non-faecal organisms comprising the intermediate-aerogenes-cloacae (I.A.C.) organisms. All available evidence tends to show that Bact. colitype I is by far the most frequent organism in the human and animal intestine. Levine (1921) has summarized the figures of various workers and obtained a percentage ratio of 93·4:6·6 as the ratio of coli:aerogenes in faeces, while Bardsley (1938) has shown that in only a very few cases does the number of I.A.C. organisms exceed the faecal coli in faeces.

Toxocariasis is a very prevalent zoonotic disease worldwide. Recently, investigators have focused more on Toxocara spp. seroprevalence in humans. Information regarding Toxocara seroprevalence in people from different ethnic backgrounds in China is limited. For this study, blood samples were collected from a total of 802 Han, 520 Korean, 303 Manchu, and 217 Mongol subjects from Jilin and Shandong provinces. The overall Toxocara seroprevalence was 16·07% (14·21% Han, 20·58% Korean, 11·22% Manchu, 18·89% Mongol). Living in suburban or rural areas, having dogs at home, exposure to soil, and consumption of raw/undercooked meat were risk factors for Toxocara infection. Exposure to soil was identified as the major risk factor for Toxocara seropositivity in all of the tested ethnicities. To the best of our knowledge, this is the first report concerning Toxocara infection in Manchus and Mongols in China. The present study provided baseline data for effective prevention strategies of toxocariasis in northeast China and recommends improvements in personal hygiene standards to achieve this goal.

Botulism is a severe neuroparalytic disorder that can be potentially life-threatening. In Barcelona, Spain, no outbreaks had been reported in the past 25 years. However, in September 2011, two outbreaks occurred involving two different families. A rare case of Clostridium baratii which produced a neurotoxin F outbreak was detected in five family members who had shared lunch, and several days before that another family was affected by C. botulinum toxin A which was probably present in homemade pâté.

Ninety-five patients with recurrent pyogenic cholangitis had a range of specimens taken at laparotomy for bacterial culture. Bacteria were isolated from 68 % of cases. Escherichia coli was the predominant pathogen. Other aerobic and anaerobic intestinal bacteria were also isolated. Liver biopsy, bile and gallstones were the most rewarding specimens for culture. Infection was usually localized, but systemic infection occurred occasionally. The site of infection is probably in the liver parenchyma; however, the route by which intestinal bacteria invade the liver is not known. Sixty per cent of the cases of recurrent pyogenic cholangitis had gallstones and 20% were infected with Clonorchis sinensis.

1. The total reproductive performance of two groups each of twenty-four mice over a period of one year under two different systems of mating has been recorded.

2. In the first system (monogamous pairs) the male was kept continuously with the female; in 78% of cases the females became pregnant again at post-partum oestrus and were thus subjected for the most part to unbroken intensive breeding.

3. In the second system (polygynous groups) several females were kept with one male and were removed to individual cages for the birth and rearing of the litters and were returned to the male again only after the litter had been weaned.

4. Under the first system 1149 young were successfully reared to weaning in one year by the twenty-four females; under the second system 559 young were weaned during the same period.

5. Mortality of breeding females, litter size, weight of young at weaning, the effect of parity, loss of litters and of young between birth and weaning and the sex-ratio of the young weaned were alike for both methods of mating.

6. The interaction of concurrent gestation and lactation upon the length of the gestation period is discussed, and regression lines showing the relation between the number of young suckled, the number of young in the uterus and the length of the gestation period are given.

My best thanks are due to Dr A. S. Parkes, F.R.S., for advice during the course of the work and for help in the preparation of the manuscript. I should also like to thank Dr C. W. Emmens for the statistical analyses and the calculation of the regression lines.

1. Conditions are described under which the three types of live or formalin-inactivated poliomyelitis viruses can be concentrated 10–100 times in good yield, with elimination of approximately 90% of the extraneous protein normally present in poliovaccines.

2. It was shown that 0·1–0·2 mg./ml. AlPO4 almost quantitatively adsorbed the antigens, provided the adsorptions were carried out at a pH round about 5. Re-elution of the antigens occurred readily at pH 7–pH 8.

3. No noticeable conversion of the ‘D-antigen’ to the ‘C-antigen’ occurred during the concentration.

The action of univalent and bivalent salts on bacteria in affeting the conductivity of thick emulsions of the meningococcus and B. coli demonstrates the important fact, that they alter the conductivity of these germs in the living condition, in a very definite manner. In this alteration, the predominant part is played by the cat-ion.

All monovalent cat-ions, with the exception of the H-ion, such as those of Na, K, Li, Rb, produce a rapid increase in conductivity or a fall in resistance. In its early stages this increase in conductivity is readily reversible in these solutions. If allowed to follow its due course, however, it leads finally to death in about two hours, when the bacterial cells no longer offer any resistance to the passage of the ions. The conductivity of the emulsion then becomes that of the fluid in which the emulsion has been suspended.

Bivalent cat-ions and the H-ion, on the other hand, at first produce a slight fall in conductivity or an increase in resistance, followed, swecondly, by an irreversible increase in conductivity which is slow and gradual resulting finally in death after 48 or more hours. This is shown by the car-ions of Ca, Sr, Ba, and Cd.

In a balanced solution such as sea-water, blood plasma, Ringer's solution, van't Hoff's solution, where a certain quantity of CaCl2 antagonises a larger amount of NaCl and KCl, the conductivity of bacterial emulsions undergoes no change, but remains constant.

Dead in distinction to living bacteria offer little resistance to the passage of ions of a solution. It would seem the relativity high resistance of the bacterial cell is due to some condition present in the living and absent in the dead state.

It has been shown by experiments on animals that the condition of increased conductivity of the cell is coupled with a loss of virulence in the case of some pathogenic bacteria. It is not clear from these experiments if this is due to the actual death of the germs in a monovalent salt solution, or to a detoxicating action of these solutions on the germs. It would seem there is some evidence for believing that the latter takes place, as the lost lethal power returns in the presence of a small trace of Ca. In bivalent salt solutions no loss of toxicity takes place. It has been pointed out that the action of monovalent and bivalent salts on bacteria offers a new explanation of certain experiments with gas gangrene organisms, where it is at present considered that the action of the salts are on the tissues of the animal and not on the bacteria.

This study aimed to explore the spatio-temporal patterns, geographical co-distribution, and socio-ecological drivers of childhood pneumonia and diarrhoea in Queensland. A Bayesian conditional autoregressive model was used to quantify the impacts of socio-ecological factors on both childhood pneumonia and diarrhoea at a postal area level. A distinct seasonality of childhood pneumonia and diarrhoea was found. Childhood pneumonia and diarrhoea were mainly distributed in the northwest of Queensland. Mount Isa city was the high-risk cluster where childhood pneumonia and diarrhoea co-distributed. Emergency department visits (EDVs) for pneumonia increased by 3% per 10-mm increase in monthly average rainfall in wet seasons. By comparison, a 10-mm increase in monthly average rainfall may cause an increase of 4% in EDVs for diarrhoea. Monthly average temperature was negatively associated with EDVs for childhood diarrhoea in wet seasons. Low socioeconomic index for areas (SEIFA) was associated with high EDVs for childhood pneumonia. Future pneumonia and diarrhoea prevention and control measures in Queensland should focus more on Mount Isa.

In a previous communication (1921) experiments have been described showing the effect produced by continuously adding normal mice to a cage, the population of which is infected with bacilli of the group which includes B. gaertner and B. suipestifer. It was seen that under these circumstances the spread of infection progresses in a series of epidemic waves, and that the survival-time of any batch of mice varies according to the period at which they are introduced to the cage. It was further shown that, if such regular and continuous addition of susceptible animals be persisted in over long periods of time, all the micewill eventually succumb, while, if the addition of new individuals be discontinued, the epidemic will eventually subside, leaving a proportion of survivors who may remain in apparently good health over a considerable period.

Clostridioides (Clostridium) difficile infection (CDI) is the leading cause of infectious diarrhoea in hospitalised patients, representing a substantial economic burden driven mainly by increased length of hospital stay (LoS). Currently in Japan, limited evidence on CDI-associated excess LoS is available. We conducted a retrospective, matched-cohort study using a large, Japanese, hospital-based administrative database. CDI was defined as CDI treatment plus either CDI diagnosis or positive enzyme immunoassay result. Propensity score matching at the time of CDI or recurrent CDI (rCDI) onset was applied to adjust baseline confounding and immortal time bias. The analysis included 5 994 054 hospitalisation records during 2008–2017, of which 11 823 were identified as CDI and 1359 as rCDI. The median excess LoS attributable to CDI and rCDI was 3 days and 6.5 days, respectively. The excess mortality attributable to CDI was 6.9%; there was no excess mortality attributable to rCDI (−1.9%). The median difference in costs attributable to CDI and rCDI during the residual stay was JPY 130 296 (USD 1185) and JPY 81 054 (USD 737) per hospitalisation, respectively. By adjusting the biases, the burden of CDI in Japan was evaluated. The findings could support decision making and resource allocation for CDI management in Japanese hospitals.

Serotype 1 Streptococcus pneumoniae is a cause of invasive pneumococcal disease (IPD) worldwide and has been associated with IPD outbreaks, while carriage is rarely detected in healthy adults or children. This study details an Australian multi-state and territory outbreak of serotype 1 S. pneumoniae IPD between 2010 and 2012. Molecular characterization demonstrated the outbreak was largely due to the clonal expansion of sequence type 306, MLVA type 261 S. pneumoniae serotype 1.

Echovirus type 11 (echo 11) has been isolated at the virus laboratory of Fairfield Hospital, Melbourne, Australia, in 20 of the 28 years since the laboratory was established. During this time two major epidemics have occurred; the first, in 1971–2 involved 90 patients with aseptic meningitis or respiratory illness. The second began in June 1979 and lasted for 11 months, during which echo 11 was isolated from 174 patients admitted to Fairfield Hospital, other Victorian and Tasmanian hospitals and a children's reception centre. The patients' illnesses included viral meningitis (66%), fever (10%), respiratory infections (7%) and gastroenteritis (2%). One baby died.

Echo 11 was recovered from nasopharyngeal swabs or aspirates, cerebrospinal fluid and faecal specimens and was isolated most frequently in the Borrie cell line. Isolates were readily identified by immune electron microscopy and/or neutralization tests.

Serological investigations were carried out on 147 patients with Paul—Bunnell positive infectious mononucleosis (IM) from the general population. All possessed antibody to the Epstein—Barr virus (EBV) and 63% showed serological evidence of recent infection. Contacts of 132 patients, 306 in all, were followed serologically; within 6 months of the index cases' illness twenty one contacts developed evidence of EBV infection or re-infection and of these five developed overt IM. The secondary attack rate of EBV infection among susceptible contacts was at least 19%; the corresponding figure for clinically apparent IM was 6%. EBY antibody prevalence among patients' siblings was significantly lower than among age-matched controls, suggesting that cases of IM come from families with a lower than normal previous experience of the virus. Of thirteen patients with persistently Paul—Bunnell negative ‘glandular fever’ four had serological evidence of recent EBV infection and two had probable cytomegalovirus mononucleosis. Recent EBV infection may have been associated with the illnesses of five of the remaining patients.

Data were collected on 6578 patients diagnosed with AIDS at 52 clinical centres in 17 European countries during an 11-year period from 1979 to 1989. The centres were divided into four regions, North, Central, Southeast, and Southwest. Differences in the incidence of most AIDS-defining opportunistic infections and malignancies were found. After adjusting for known possible confounders, statistically significant differences between regions remained. Pneumocystis carinii pneumonia (PCP) was more common in Northern Europe, Kaposi's sarcoma and toxoplasmosis in Central Europe, cytomegalovirus retinitis in South-eastern Europe, and extrapulmonary tuberculosis in South-western Europe. These differences we attribute primarily to different degrees of exposure to the respective underlying pathogens. The prevalence of these and other micro-organisms will determine the clinical course of HIV infections in parts of Eastern Europe and elsewhere where the virus now is spreading.

West Nile virus (WNV) infection is an emerging zoonosis that threatens global public health. In this study, a total of 95 bird serum samples from 14 species and 341 horse serum samples were collected from 2008 to 2010 in Shanghai, China. All serum samples were screened initially for WNV-reactive antibodies using a competitive ELISA. The positive samples detected by ELISA were further confirmed using a plaque-reduction neutralization test (PRNT) for WNV and its most closely related flaviviruses in the area to avoid false positives due to cross-reactivity. Five (5·3%) of the bird serum samples and none (0·0%) of the horse serum samples tested positive for WNV antibodies. The findings strongly suggest that some of the birds, specifically the resident birds in China, had been exposed to WNV.

In this paper we propose a debate on the role of mathematical models in evaluating control strategies for vector-borne infections. Mathematical models must have their complexity adjusted to their goals, and we have basically two classes of models. At one extreme we have models that are intended to check if our intuition about why a certain phenomenon occurs is correct. At the other extreme, we have models whose goals are to predict future outcomes. These models are necessarily very complex. There are models in between these classes. Here we examine two models, one of each class and study the possible pitfalls that may be incurred. We begin by showing how to simplify the description of a complicated model for a vector-borne infection. Next, we examine one example found in a recent paper that illustrates the dangers of basing control strategies on models without considering their limitations. The model in this paper is of the second class. Following this, we review an interesting paper (a model of the first class) that contains some biological assumptions that are inappropriate for dengue but may apply to other vector-borne infections. In conclusion, we list some misgivings about modelling presented in this paper for debate.

During a 5-year (2007–2011) surveillance period a total of 435 (15·34%) of 2834 stool specimens from children aged <14 years with acute gastroenteritis tested positive for norovirus and 217 strains were characterized upon partial sequence analysis of the polymerase gene as either genogroup (G)I or GII. Of the noroviruses, 99·2% were GII with the GII.P4 genotype being predominant (80%). GII.P4 variants (Yerseke 2006a, Den Haag 2006b, Apeldoorn 2008, New Orleans 2009) emerged sequentially during the study period. Sequence analysis of the capsid gene of 57 noroviruses revealed that 7·8% were recombinant (ORF1/ORF2) viruses including GII.P7_GII.6, GII.P16_GII.3, GII.P16_GII.13, GII.Pe_GII.2, and GII.Pe_GII.4, never identified before in Italy. GII.P1_GII.1, GII.P2_GII.1, GII.P3_GII.3 and GII.P6_GII.6 strains were also detected. Starting in 2011 a novel GII.4 norovirus with 3–4% nucleotide difference in the polymerase and capsid genes from variant GII.4 New Orleans 2009 was monitored in the local population. Since the epidemiology of norovirus changes rapidly, continuous surveillance is necessary to promptly identify the onset of novel types/variants.

Of 918 severely subnormal patients in mental deficiency hospitals in Lincolnshire 917 were tested by the toxoplasmin skin tests, forty-nine out of 265 patients were dye tested because of a positive skin test or other indication. All patients in another group of 655 subnormals were dye tested, and comparison of these results with those of groups from the normal population showed that in children there was an excess of about 20% of dye-test positivity among the subnormals—a figure identical with that found by Thalhammer in Vienna.

The excess of positives became progressively less with increasing age and by middle age the incidence was the same in subnormals as among blood donors in the county. It is suggested that this indicates that patients in hospital are exposed to a lower risk of acquiring infection and that the higher incidence among adult males than among adult female defectives is due to the fact that more of them go out to work, many of them on farms. This factor could also explain the lower incidence of positivity in adult mongols and epileptics who are less commonly employable.

Possible explanations of the higher incidence among subnormal than among control children are discussed. Although it is tempting to assume that it indicates that some may be cases of congenital toxoplasmosis, the lack of gradient between child mongols, child epileptics and other subnormal children does not support this hypothesis. The numbers of mongol and epileptic children were too small to give statistically significant results. It is possible that the home environments of severely subnormal children exposed them to a higher risk of infection than did the homes of the control children and that the observed excess of dye and skin-test positivity may be due to increased incidence of acquired infection before their admission to hospital.

It was found that there was reasonable concordance between the dye test at a titre of 1/8 and skin sensitivity reactions exceeding 7 mm. in diameter, but poor agreement if 10 mm. was taken as the criterion of positivity.

Despite the lesser sensitivity of the skin test, the pattern of the results was the same as that observed in the dye-test survey, and the value of the skin-test for epidemiological surveys was confirmed.

England has recently started a new paediatric influenza vaccine programme using a live-attenuated influenza vaccine (LAIV). There is uncertainty over how well the vaccine protects against more severe end-points. A test-negative case–control study was used to estimate vaccine effectiveness (VE) in vaccine-eligible children aged 2–16 years of age in preventing laboratory-confirmed influenza hospitalisation in England in the 2015–2016 season using a national sentinel laboratory surveillance system. Logistic regression was used to estimate the VE with adjustment for sex, risk-group, age group, region, ethnicity, deprivation and month of sample collection. A total of 977 individuals were included in the study (348 cases and 629 controls). The overall adjusted VE for all study ages and vaccine types was 33.4% (95% confidence interval (CI) 2.3–54.6) after adjusting for age group, sex, index of multiple deprivation, ethnicity, region, sample month and risk group. Risk group was shown to be an important confounder. The adjusted VE for all influenza types for the live-attenuated vaccine was 41.9% (95% CI 7.3–63.6) and 28.8% (95% CI −31.1 to 61.3) for the inactivated vaccine. The study provides evidence of the effectiveness of influenza vaccination in preventing hospitalisation due to laboratory-confirmed influenza in children in 2015–2016 and continues to support the rollout of the LAIV childhood programme.