This retrospective study highlights the degree of losses and time-course through which the 2015 highly pathogenic avian influenza (HPAI) outbreaks in Ghana were managed. A total of 102 760 birds from 35 farms across five regions in Ghana included in this study were affected. Out of this, 89.3% was from the Greater Accra region. Majority of the birds were culled (94.2%). Adult layers were most affected and destroyed (64.0%), followed by broilers (13.7%). Event initiation to reporting averaged 7.7 ± 1.3 days (range: 1–30 days). Laboratory confirmation to depopulation of birds averaged 2.2 ± 0.5 (0–15) days while depopulation to disinfection took 2.2 ± 0.7 (0–20) days. Overall, some farms took as long as 30 days to report the outbreak to the authorities, 15 days from confirmation to depopulation and 20 days from depopulation to disinfection. On average, outbreak management lasted 12.3 (2–43) days from event initiation to depopulation. The study reveals a significant number of avian losses and delays in HPAI reporting and management by the authorities in Ghana during the 2015 outbreak. This poses a high risk of spread to other farms and a threat to public health. Awareness creation for poultry farmers is necessary for early reporting, while further study is required to set thresholds for the management of such outbreaks by veterinary departments.

1. The action in vitro of normal rabbit-serum upon B. coli commune consists usually of three or more phases, the duration of which is inversely related to temperature.

2. The latent period which occurs on first mixing bacteria and serum is followed by a period of bacterial growth, which in its turn yields to a period of bactericidal action. This may remain final or may be succeeded by a second period of growth.

3. The germicidal action, both in case of normal rabbit-serum upon B. coli commune and of normal goat-serum upon B. typhosus, takes place in accordance with a logarithmic law so that death-rate remains proportional to the concentration of surviving bacteria.

The bactericidal action of serum thus falls into line with all other cases of disinfection, hitherto investigated.

4. The temperature coefficient of the bactericidal action of serum is low in comparison with that found for other germicides, being 2·84 per 10°C. rise in temperature for normal rabbit-serum and B. coli commune and 1·93 in the case of normal goat-serum and B. typhosus.

5. Growth of B. coli commune in rabbit-serum takes place logarithmically so that the concentration of living bacteria after equal intervals of time form terms of a geometrical series.

The calculated value of the generation-time is slightly greater than that obtaining in broth at the same temperature.

6. The influence of temperature upon rate of bacterial growth in serum is comparable with the effect upon growth in other media. The generation-time is decreased 2·01-fold for a rise in temperature of 10°C.

7. The separate processes of bacteinal growth and death in serum being similarly influenced by temperature, there is no support for the view that the significance of fever might be concerned with a tendency to encourage either process relative to the other.

The effectiveness of the single-dose poison treatments of farm rat infestations, analysed by comparing the weights of the post-treatment census bait takes in covariance with the weights of the prebait takes, showed that treatments with 2·5% zinc phosphide, 0·3% thallium sulphate or 0·3% gophacide were equally effective and significantly better than were treatments with 1% zinc phosphide or 0·1% thallium sulphate. The methodology and sensitivity of different analyses are also considered.

Norovirus (NoV) epidemics normally peak in December in Japan; however, the peak in the 2009–2010 season was delayed until the fourth week of January 2010. We suspected intensive hand hygiene that was conducted for a previous pandemic influenza in 2009 as the cause of this delay. We analysed the NoV epidemic trend, based on national surveillance data, and its associations with monthly output data for hand hygiene products, including alcohol-based skin antiseptics and hand soap. The delayed peak in the NoV incidence in the 2009–2010 season had the lowest number of recorded cases of the five seasons studied (2006–2007 to 2010–2011). GII.4 was the most commonly occurring genotype. The monthly relative risk of NoV and monthly output of both alcohol-based skin antiseptics and hand soap were significantly and negatively correlated. Our findings suggest an association between hand hygiene using these products and prevention of NoV transmission.

We assessed the role of tuberculosis (TB) disease and HIV infection on the level of physical activity. A combined heart rate and movement sensor was used to assess habitual physical activity in TB patients and non-TB controls. The association between sputum-negative TB, sputum-positive TB, HIV and physical activity estimates were assessed in multivariable linear regression models adjusted for age, sex, haemoglobin and alpha-1-acid glycoprotein (AGP). Sputum-positive [eB 0·43, 95% confidence interval (CI) 0·29–0·64] and sputum-negative (eB 0·67, 95% CI 0·47–0·94) TB as well as HIV infection (eB 0·59, 95% CI 0·46–0·75) were associated with reduced activity compared to controls. Anaemia accounted for a substantial part of the effects of HIV, while elevated AGP primarily mediated the TB effect. The level of physical activity is highly influenced by TB and HIV, and mainly mediated through anaemia of infection and associated with elevated acute phase response.

Two new Salmonella types are described. S. minnesota was isolated from a turkey. Its antigenic formula is XXI: b ⇋ enx. S. worthington was found both in a chicken and in a turkey. Its antigenic formula is I XIII XXIII: Iw ⇋ z…. Transfers of each type have been deposited in the National Collection of Type Cultures of Great Britain and in the American Type Culture Collection.

Seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG antibodies, using dried blood spots, was determined in October–November 2020, among residents and staff randomly selected from 20 nursing homes (NH) geographically distributed in Flanders, Belgium. Sociodemographic and medical data [including coronavirus disease 2019 (COVID-19) symptoms and results of RT-PCR tests] were retrieved using questionnaires. The overall seroprevalence was 17.1% [95% confidence interval (CI) 14.9–19.5], with 18.9% (95% CI 15.9–22.2) of the residents and 14.9% (95% CI 11.9–18.4) of the staff having antibodies, which was higher than the seroprevalence in blood donors. The seroprevalence in the 20 NH varied between 0.0% and 45.0%. Fourteen per cent of the staff with antibodies, reported no typical COVID-19 symptoms, while in residents, 51.0% of those with antibodies had no symptoms. The generalised mixed effect model showed a positive association between COVID-19 symptoms and positive serology, but this relation was weaker in residents compared to staff. This study shows that NH are more affected by SARS-CoV-2 than the general population. The large variation between NH, suggests that some risk factors for the spread among residents and staff may be related to the NH. Further, the results suggest that infected people, without the typical COVID-19 symptoms, might play a role in outbreaks.

Of the chemical structure of antibodies little or nothing is known. It is generally held that the specific properties of an antiserum are closely associated with the globulin fraction. An antiserum may be distinguished from a normal serum by the precipitation of some of its globulins in the presence of the homologous antigen. The formation of a precipitate in a mixture of antigen and antiserum may be explained in either of two ways: (1) The reaction which occurs when antigen is added to antiserum may produce such physical changes in the mixture that normal globulin is precipitated. The reaction takes place between two specific substances, the antigen and the antibody, and is rendered visible by the presence of a non-specific globulin which plays the part of an indicator. (2) Or we may suppose that in the process of immunisation the antigen produces a specific alteration in the structure of the globulin. That is to say, the antibody is a specifically altered globulin, which has undergone some change in its molecular structure, in virtue of which it can react and combine with the homologous antigen.

A review of 194 cases of enteric infection in Scotland during 1967–74, is reported. Diagnosis was confirmed by the laboratory isolation of Salmonella typhi (64 cases), S. paratyphi A (3) and S. paratyphi B (127), from blood or faeces; 174 persons were clinically ill and 20 were symptomless infections.

Most patients (81·0%) were under 35 years of age, with the highest incidence occurring among young adults of 15–24 years, many of whom had been travelling overseas. One-third of all cases (65) were imported infections; the remaining 129 patients had not been outside the United Kingdom. A significantly greater proportion of typhoid infection (54·7%) was contracted overseas, in contrast to paratyphoid B with only one-fifth of cases (21·2%) being imported; all three cases of paratyphoid A were imported. The geographic distribution of origin of imported infections is discussed, along with the frequency of organisms belonging to different phage types.

Two deaths occurred, one of which was the result of complications of paratyphoid fever. All other patients responded well to treatment, although two persons continued to excrete and became chronic carriers.

A few examples are given of episodes of particular epidemiological interest.

It is expected that in future years there will be a continued increase in the proportion of imported infections as more persons travel overseas, concurrent with the continuing decline in the number of chronic carriers resident in the British Isles.

Using the data provided by Fiji's ministry of health and medical services, we apply an implicit time-discrete SIR (susceptible people–infectious people–removed people) model that tracks the transmission and recovering rate at time, t to predict the trend of the coronavirus disease 2019 (COVID-19) pandemic in Fiji. The model implied time-varying transmission and recovery rates were calculated from 4 May 2021 to 9 October 2021. The estimator functions for these rates were determined, and a short-term (30 days) forecast was done. The model was validated with observed values of the active and recovered cases from 11 October 2021 to 9 December 2021. Statistical results reveal a good fit of profiles between model simulated and the reported COVID-19 data. The gradual decrease of the time-varying basic reproduction number with values below one towards the end of the study period suggest the government's success in controlling the epidemic. The mean reproduction number for the second wave of COVID-19 in Fiji was estimated as 2.7818. The results from this study can be used by researchers, the Fijian government, and the relevant health policy makers in making informed decisions should a third COVID-19 wave occur.

This study was performed to investigate space–time patterns of Campylobacter spp. colonization in broiler flocks in Norway. Data on the Campylobacter spp. status at the time of slaughter of 16 054 broiler flocks from 580 farms between 2002 and 2006 was included in the study. Spatial relative risk maps together with maps of space–time clustering were generated, the latter by using spatial scan statistics. These maps identified the same areas almost every year where there was a higher risk for a broiler flock to test positive for Campylobacter spp. during the summer months. A modified K-function analysis showed significant clustering at distances between 2·5 and 4 km within different years. The identification of geographical areas with higher risk for Campylobacter spp. colonization in broilers indicates that there are risk factors associated with Campylobacter spp. colonization in broiler flocks varying with region and time, e.g. climate, landscape or geography. These need to be further explored. The results also showed clustering at shorter distances indicating that there are risk factors for Campylobacter spp. acting in a more narrow scale as well.

Bacteriological monitoring of penicillin therapy in 30 children with streptococcal sore throats was performed by means of salivary and throat-swab culture, on the first, third, fifth and ninth days after therapy had started. Counts of beta-haemolytic streptococci per ml. of saliva were also performed.

Results showed that salivary culture and estimation of the numbers of beta-haemolytic streptococci in the saliva were much more sensitive indices of the effectiveness of penicillin treatment than throat-swab culture.

We investigated whether straight-line distance from residential compounds to healthcare facilities influenced mortality, the incidence of pneumonia and vaccine efficacy against pneumonia in rural Gambia. Clinical surveillance for pneumonia was conducted on 6938 children living in the catchment areas of the two largest healthcare facilities. Deaths were monitored by three-monthly home visits. Children living >5 km from the two largest healthcare facilities had a 2·78 [95% confidence interval (CI) 1·74–4·43] times higher risk of all-cause mortality compared to children living within 2 km of these facilities. The observed rate of clinical and radiological pneumonia was lower in children living >5 km from these facilities compared to those living within 2 km [rate ratios 0·65 (95% CI 0·57–0·73) and 0·74 (95% CI 0·55–0·98), respectively]. There was no association between distance and estimated pneumococcal vaccine efficacy. Geographical access to healthcare services is an important determinant of survival and pneumonia in children in rural Gambia.

1. The membrane piece technique for in vitro titrations of the infectivity of influenza virus is described. Rectangles of shell, about 8 × 25 mm., with the chorio-allantoic membrane still attached (membrane pieces) are cut from thirteenth-day fertile eggs. One piece in a test-tube with glucose-buffered salt solution forms an individual assay unit. Five or more tubes are inoculated with each virus dilution. After incubation at 37° C. for 72 hr., with agitation for the first 24 hr. the fluid in each tube is tested for haemagglutinins. From the results at each dilution, an estimate of the 50% membrane piece (MP50) infectivity titre is obtained.

2. Six hundred assay units, with pieces cut from twenty eggs, can be set up by two workers in 1 hr. and used for titration of between three and twenty-four individual virus preparations, depending on the reliability desired for the 50% end-point estimates.

3. With the D.S.P. and PR 8 strains of influenza A virus, the MP50 titres parallel the EID50 titres from egg titrations, but are eight times and twenty times lower, respectively. The MP50: EID50 ratio is the same for various preparations of the same strain, including standard allantoic fluid and chorio-allantoic membrane virus, incomplete virus, and inactivated (heated) allantoic fluid virus. Preliminary experiments with Lee influenza B virus show that slightly different experimental conditions are required, and the MP50 titres are about fifty times less than the EID50 titres.

4. Consistent results have been obtained on titration of samples of the same virus preparation on a number of occasions over a period of several months.

5. A large number of membrane pieces can be used to test each virus dilution, and sampling variations in the MP50 estimates thus made quite small. Statistical data on the reliability of a 50 % titration result, and on the minimum significant differences between two end-points, are given for different values of n, the number of membrane pieces used to test each virus dilution, and of d, the log dilution step.

We are grateful to Mr J. Collins for invaluable technical assistance, and also to Miss I. Allen for help with the computations.

Hepatitis B virus (HBV) vaccination has been part of the Expanded Programme of Immunization (EPI) in Tunisia since 1995. The aim of this study was to evaluate, for the first time, the impact of mass vaccination in Tunisia 17 years after this programme was implemented, and in parallel, assess the long-term persistence of anti-HBs antibody in the vaccinated Tunisian population. A total of 1422 students were recruited (703 vaccinated, 719 non-vaccinated). HBV seromarkers were checked. None of the students from either group had positive HBsAg. The overall prevalence of anti-HBc was 0·8%. A Significantly higher prevalence of anti-HBc was noted in unvaccinated students than in vaccinated (1·4% vs. 0·3%, P = 0·02). The overall seroprotection rate (anti-HBs titre ⩾10 mIU/ml) was 68·9% in vaccinated subjects. Seroprotection rates and geometric mean titres decreased significantly with increasing age, reflecting waning anti-HBs titre over time. No significant difference was detected between seroprotection rates and gender or students’ area of origin. Incomplete vaccination was the only factor associated with an anti-HBs titre <10 mIU/ml. This study demonstrates the excellent efficacy of the HBV vaccination programme in Tunisia 17 years after its launch. However, a significant decline of anti-HBs seroprotection has been observed in ⩾15-year-old adolescents which places them at risk of infection. Additional studies are needed in hyperendemic regions in Tunisia.

Approximately 80 million people live with chronic hepatitis B virus (HBV) infection in the WHO Africa Region. The natural history of HBV infection in this population is poorly characterised, and may differ from patterns observed elsewhere due to differences in prevailing genotypes, environmental exposures, co-infections, and host genetics. Existing research is largely drawn from small, single-centre cohorts, with limited follow-up time. The Hepatitis B in Africa Collaborative Network (HEPSANET) was established in 2022 to harmonise the process of ongoing data collection, analysis, and dissemination from 13 collaborating HBV cohorts in eight African countries. Research priorities for the next 5 years were agreed upon through a modified Delphi survey prior to baseline data analysis being conducted. Baseline data on 4,173 participants with chronic HBV mono-infection were collected, of whom 38.3% were women and the median age was 34 years (interquartile range 28–42). In total, 81.3% of cases were identified through testing of asymptomatic individuals. HBeAg-positivity was seen in 9.6% of participants. Follow-up of HEPSANET participants will generate evidence to improve the diagnosis and management of HBV in this region.

To investigate the frequencies of dendritic cells (DCs) and Toll-like receptor 3 (TLR3) in neonates of HBsAg-positive mothers with different HBV serological profiles, we conducted a study in Taiyuan, China. The study included 144 HBsAg-positive mothers and their neonates. The frequencies of DCs and TLR3 were determined using four-colour flow-cytometric analysis. DC and TLR3 frequencies were not related to HBV intrauterine transmission, maternal HBeAg positivity, maternal HBV DNA positivity and HBeAg/HBV DNA double-positivity. The plasmacytoid dendritic cell (pDC) frequencies in neonates whose maternal HBV DNA was >5 × 107 copies/ml decreased significantly compared to that in neonates whose maternal HBV DNA was ⩽5 × 107 copies/ml (Z = − 2·170, P = 0·03) or whose maternal HBV DNA was negative (Z = − 1·981 P = 0·048). This study suggests that neonatal pDC frequencies decrease when maternal HBV DNA loads are >5 × 107 copies/ml.

Hepatitis E virus genotype 1 (HEV G1) is an important cause of morbidity and mortality in Africa and Asia. HEV G1's natural history, including the incubation period, remains poorly understood, hindering surveillance efforts and effective control. Using individual-level data from 85 travel-related HEV G1 cases in England and Wales, we estimate the incubation period distribution using survival analysis methods, which allow for appropriate inference when only time ranges, rather than exact times are known for the exposure to HEV and symptom onset. We estimated a 29.8-day (95% confidence interval (CI) 24.1–36.0) median incubation period with 5% of people expected to develop symptoms within 14.3 days (95% CI 10.1–21.7) and 95% within 61.9 days (95% CI 47.4–74.4) of exposure. These estimates can help refine clinical case definitions and inform the design of disease burden and intervention studies.

The possible association between Toxoplasma gondii infection and paediatric haematological malignancies in a group of patients and control subjects was evaluated in the present study. We performed an age-, gender- and residence frequency-matched case–control study of 101 blood cancer patients under 18 years of age, all of which were treated in Amirkola Pediatric Hospital. One hundred and thirty-eight control samples were gathered from the outpatient clinic in the hospital. All cases and controls were tested for the presence of anti-Toxoplasma IgG antibodies and then IgG-positive subjects were evaluated for IgM antibodies by enzyme-linked immunoassays. Anti-T. gondii IgG antibodies were found in 37 (36.6%) of the cases and 12 (8.7%) subjects in the control group (odds ratio 6.07, 95% confidence interval 2.963–12.437, P < 0.0001). The median and interquartile range (IQR) of IgG titre from case group (7.7 (IQR 0.25–13.5)) was higher than the control (0.2 (IQR 0.1–0.5)) (P < 0.0001). The frequency of anti-T. gondii antibodies (IgG) in lymphoblastic leukaemia (acute lymphoblastic leukaemia), Hodgkin's lymphoma and T–cell lymphoma were 33 (31.9%), 3 (50%) and 1(100%), respectively. Anti–T. gondii IgM was not detected in the IgG-positive patients in case group. In the case subjects, no significant difference was seen in the positive rates of T. gondii infection between genders (37.3% in male; 35.7% in female; P = 0.52) and ages groups (P = 0.31). This study demonstrated that T. gondii infection is prevalent in children with blood cancer. It also showed that toxoplasmosis may possibly be linked with an increased risk of childhood haematologic malignancies. Furthermore, these results may be helpful in research on blood neoplasia aetiology.

A technique for carrying out the anti-globulin test with Salm. typhi O suspension in described; this technique has been used to examine a number of human sera. The degree of amplification of agglutinin titre and the final titres obtained were appreciably greater in the sera of individuals with a history of Salm. typhi infection, some of whom were carriers, than in the sera of normal individuals.