No evidence was found to support the view that coliphages as such play an important role in reducing the number of E. coli in sewage water when it is treated in oxidation ponds. Coliphages seem to have greater powers of survival than E. coli in oxidation ponds.

Epidemiologists agree that there is a prevailing seasonality in the presentation of epidemic waves of respiratory syncytial virus (RSV) infections and influenza. The aim of this study is to quantify the potential relationship between the activity of RSV, with respect to the influenza virus, in order to use the RSV seasonal curve as a predictor of the evolution of an influenza virus epidemic wave. Two statistical tools, logistic regression and time series, are used for predicting the evolution of influenza. Both logistic models and time series of influenza consider RSV information from previous weeks. Data consist of influenza and confirmed RSV cases reported in Comunitat Valenciana (Spain) during the period from week 40 (2010) to week 8 (2014). Binomial logistic regression models used to predict the two states of influenza wave, basal or peak, result in a rate of correct classification higher than 92% with the validation set. When a finer three-states categorization is established, basal, increasing peak and decreasing peak, the multinomial logistic model performs well in 88% of cases of the validation set. The ARMAX model fits well for influenza waves and shows good performance for short-term forecasts up to 3 weeks. The seasonal evolution of influenza virus can be predicted a minimum of 4 weeks in advance using logistic models based on RSV. It would be necessary to study more inter-pandemic seasons to establish a stronger relationship between the epidemic waves of both viruses.

The life cycle of Nocardia starts-with the microcyst, which germinates by budding. The bud develops into a long multinucleate filament, which becomes divided into individual cells by the formation of transverse cell walls. Microcysts are formed in the same manner as in the Eubacteria. Multiplication of the cells takes place by simple fission, by complex vegetative reproduction, and by branching. They do not have a prolonged diploid phase like the Actinomyces.

A simple process is described for the desiccation of antisera after freezing by rapid evaporation. Freezing has been brought about by the rapid evaporation which takes place in a high vacuum in the presence of P2O5. The violent frothing which takes place when serum is exposed to a high vacuum has been controlled by a preliminary evacuation of the serum in the absence of the drying agent.

No special apparatus except an efficient high vacuum pump is necessary for this process.

This process has been applied for the preservation of (a) anti-horse serum, anti-ox serum, anti-human serum, anti-human globulin and anti-crystalline human albumin sera; (b) anti-sheep cell haemolysin; (c) guinea-pig complement; (d) various Salmonella antisera.

Preliminary experiments are described of the application of this method to the drying of bacteria.

We desire to thank Dr P. Hartley for his valuable advice and for showing us his paper prior to publication.

The steep increase in human West Nile virus (WNV) infections in 2011–2012 in north-eastern Italy prompted a refinement of the surveillance plan. Data from the 2010–2012 surveillance activities on mosquitoes, equines, and humans were analysed through Bernoulli space–time scan statistics, to detect the presence of recurrent WNV infection hotspots. Linear models were fit to detect the possible relationships between WNV occurrence in humans and its activity in mosquitoes. Clusters were detected for all of the hosts, defining a limited area on which to focus surveillance and promptly identify WNV reactivation. Positive relationships were identified between WNV in humans and in mosquitoes; although it was not possible to define precise spatial and temporal scales at which entomological surveillance could predict the increasing risk of human infections. This stresses the necessity to improve entomological surveillance by increasing both the density of trapping sites and the frequency of captures.

The motivations that govern the adoption of digital contact tracing (DCT) tools are complex and not well understood. Hence, we assessed the factors influencing the acceptance and adoption of Singapore's national DCT tool – TraceTogether – during the COVID-19 pandemic. We surveyed 3943 visitors of Tan Tock Seng Hospital from July 2020 to February 2021 and stratified the analyses into three cohorts. Each cohort was stratified based on the time when significant policy interventions were introduced to increase the adoption of TraceTogether. Binary logistic regression was preceded by principal components analysis to reduce the Likert items. Respondents who ‘perceived TraceTogether as useful and necessary’ had higher likelihood of accepting it but those with ‘Concerns about personal data collected by TraceTogether’ had lower likelihood of accepting and adopting the tool. The injunctive and descriptive social norms were also positively associated with both the acceptance and adoption of the tool. Liberal individualism was mixed in the population and negatively associated with the acceptance and adoption of TraceTogether. Policy measures to increase the uptake of a national DCT bridged the digital divide and accelerated its adoption. However, good public communications are crucial to address the barriers of acceptance to improve voluntary uptake widespread adoption.

Rickettsia rickettsii infection is being increasingly recognized as an important cause of fatal acute illness in Brazil, where this tick-borne disease is designated Brazilian spotted fever (BSF). In this study we report five fatal cases of BSF in employees of an animal shelter in an urban area in the municipality of Rio de Janeiro in southeast Brazil after a natural disaster on 11 January 2011. Four of the cases occurred from 27 January to 11 April 2011, while the fifth fatal case was identified in April 2012. Three cases were confirmed by molecular analysis and two by epidemiological linkage. An investigation of BSF was performed in the animal shelter, and blood samples were collected from 115 employees and 117 randomly selected dogs. The presence of high levels (1024–4096) of antibodies against spotted fever group rickettsiae was found in three (2·6%) employees and 114 (97·5%) dogs. These findings emphasize the need to consider BSF as a possible cause of undifferentiated febrile illness, especially dengue and leptospirosis, in patients occupationally exposed to dogs heavily infested by ticks, mainly working at kennels and animal shelters that have inadequate space for the animals housed and frequently providing an environment conducive to exposure to pathogens such as R. rickettsii.

The degree of protection conferred by vaccinated dams on infant mice against colonization by Campylobacter jejuni depended on the bacterial strain, preparation, and route of administration of the vaccine. In some instances of homologous protection, serum bactericidal titres correlated well with protection. However, boiled C. jejuni vaccine, which was non-protective, also elicited a strong bactericidal antibody response. Conversely, bactericidal activity could not be demonstrated against strains capable of cross-protection. There was a good correlation between high campylobacter-specific IgG response and bactericidal activity.

The spatial distribution of human cases of tick-borne diseases is probably determined by a combination of biological and socioeconomic factors. A zoonotic tick-borne pathogen, Ehrlichia chaffeensis, is increasing in human incidence in the USA. In this study, the spatial patterns of probable and confirmed E. chaffeensis-associated cases of ehrlichiosis from 2000 to 2011 were investigated at the zip-code level in Missouri. We applied spatial statistics, including global and local regression models, to investigate the biological and socioeconomic factors associated with human incidence. Our analysis confirms that the distribution of ehrlichiosis in Missouri is non-random, with numerous clusters of high incidence. Furthermore, we identified significant, but spatially variable, associations between incidence and both biological and socioeconomic factors, including a positive association with reservoir host density and a negative association with human population density. Improved understanding of local variation in these spatial factors may facilitate targeted interventions by public health authorities.

It was found that 26 of 127 infants with chlamydial conjunctivitis had previously received chloramphenicol eye drops. This treatment had delayed the onset and reduced the degree of oedema, congestion and discharge compared with infected infants with no ‘first-line’ chemotherapy, but eye swabs remained positive in 22 (85 %) of the chloramphenicol treated infants.

The problems of designing laboratory tests which might accurately forecast the clinical value, or lack of value of antibiotics in chlamydial infections were investigated. The minimum inhibitory concentration (MIC) of chloramphenicol, against Chlamydia trachomatis in McCoy cell cultures varied widely according to the antibiotic preparation used, the timing and duration of its exhibition in relation to the single step growth cycle of C. trachomatis, and, in particular, the method of examination of infected tissue cultures for residual chlamydial growth after incubation with chloramphenicol.

To determine risk factors for sporadic Vibrio parahaemolyticus gastroenteritis, we conducted a population-based case-control study in sentinel hospital surveillance areas of Shanghai and Jiangsu province, China. Seventy-one patients with diarrhoea and confirmed V. parahaemolyticus infections were enrolled, and they were matched with 142 controls for gender, age and residential area. From the multivariable analysis, V. parahaemolyticus infections were associated with antibiotics taken during the 4 weeks prior to illness [odds ratio (OR) 8·1, 95% confidence interval (CI) 1·2–56·4)], frequent eating out (OR 3·3, 95% CI 1·1–10·1), and shellfish consumption (OR 3·2, 95% CI 1·0–9·9), with population-attributable fractions of 0·09, 0·25, and 0·14, respectively. Protective factors included keeping the aquatic products refrigerated (OR 0·4, 95% CI 0·1–0·9) and pork consumption (OR 0·2, 95% CI 0·1–0·8). Further study of the association of V. parahaemolyticus gastroenteritis with prior antibiotic use and shellfish consumption is needed.

The number of dengue epidemics in Brazil has increased dramatically in the last 15 years. In this study, we analysed the seasonal patterns in the incidence of hospitalisations due to dengue across the different states of Brazil and compared these with the corresponding climatic patterns. We discovered that the seasonality of dengue hospitalisations in Brazil has a clear zonal gradient, characterised by the progression of primary peaks from West to East during the first half of the year, which may be associated with the increased vapour pressure and rainfall during this period, leading to increased mosquito abundance and activity. We also found that the proportion of children among hospitalised individuals was especially high during the peak outbreaks in 2007/2008 and 2010. This may be due to the emergence and spread of the new DENV-2 Southeast Asian genotype lineage II from 2007, which has probably arrived from the Caribbean and may have caused an increase in incidence and severity of the disease, particularly among children. Our findings may allow health systems to improve control interventions and contribute to reducing dengue morbidity and mortality by using integrated vector control in conjunction with early diagnosis and prompt supportive care.

Shiga-toxin-producing Escherichia coli (STEC) infections usually cause haemolytic uraemic syndrome (HUS) equally in male and female children. This study investigated the localization of globotriaosylceramide (Gb3) in human brain and kidney tissues removed from forensic autopsy cases in Japan. A fatal case was used as a positive control in an outbreak of diarrhoeal disease caused by STEC O157:H7 in a kindergarten in Urawa in 1990. Positive immunodetection of Gb3 was significantly more frequent in female than in male distal and collecting renal tubules. To correlate this finding with a clinical outcome, a retrospective analysis of the predictors of renal failure in the 162 patients of two outbreaks in Japan was performed: one in Tochigi in 2002 and the other in Kagawa Prefecture in 2005. This study concludes renal failure, including HUS, was significantly associated with female sex, and the odds ratio was 4·06 compared to male patients in the two outbreaks. From 2006 to 2009 in Japan, the risk factor of HUS associated with STEC infection was analysed. The number of males and females and the proportion of females who developed HUS were calculated by age and year from 2006 to 2009. In 2006, 2007 and 2009 in adults aged >20 years, adult women were significantly more at risk of developing HUS in Japan.

As a result of the COVID-19 pandemic, whether and when the world can reach herd immunity and return to normal life and a strategy for accelerating vaccination programmes constitute major concerns. We employed Metropolis–Hastings sampling and an epidemic model to design experiments based on the current vaccinations administered and a more equitable vaccine allocation scenario. The results show that most high-income countries can reach herd immunity in less than 1 year, whereas low-income countries should reach this state after more than 3 years. With a more equitable vaccine allocation strategy, global herd immunity can be reached in 2021. However, the spread of SARS-CoV-2 variants means that an additional 83 days will be needed to reach global herd immunity and that the number of cumulative cases will increase by 113.37% in 2021. With the more equitable vaccine allocation scenario, the number of cumulative cases will increase by only 5.70% without additional vaccine doses. As SARS-CoV-2 variants arise, herd immunity could be delayed to the point that a return to normal life is theoretically impossible in 2021. Nevertheless, a more equitable global vaccine allocation strategy, such as providing rapid vaccine assistance to low-income countries/regions, can improve the prevention of COVID-19 infection even though the virus could mutate.

Globally, countries have used diverse methods to report data during the COVID-19 pandemic. Using international guidelines and principles of emergency management, we compare national data reporting systems in African countries in order to determine lessons for future pandemics. We analyse COVID-19 reporting practices across 54 African countries through 2020. Reporting systems were diverse and included summaries, press releases, situation reports and online dashboards. These systems were communicated via social media accounts and websites belonging to ministries of health and public health. Data variables from the reports included event detection (cases/deaths/recoveries), risk assessment (demographics/co-morbidities) and response (total tests/hospitalisations). Of countries with reporting systems, 36/53 (67.9%) had recurrent situation reports and/or online dashboards which provided more extensive data. All of these systems reported cases, deaths and recoveries. However, few systems contained risk assessment and response data, with only 5/36 (13.9%) reporting patient co-morbidities and 9/36 (25%) including total hospitalisations. Further evaluation of reporting practices in Cameroon, Egypt, Kenya, Senegal and South Africa as examples from different sub-regions revealed differences in reporting healthcare capacity and preparedness data. Improving the standardisation and accessibility of national data reporting systems could augment research and decision-making, as well as increase public awareness and transparency for national governments.

Co-circulation of Chikungunya and Dengue viral infections (CHIKV and DENV) have been reported mainly due to transmission by common Aedes vector. The purpose of the study was to identify and characterise the circulating strains of CHIKV and DENV in DENV endemic region of New Delhi during 2016. CHIKV and DENV were identified in the blood samples (n = 130) collected from suspected patients by RT-PCR. CHIKV was identified in 26 of 65 samples (40%). Similarly, DENV was detected in 48 of 120 samples (40%). Co-infection with both the viruses was identified in five (9%) of the samples. Interestingly, concurrent infection with DENV, CHIKV and Plasmodium vivax was detected in two samples. CHIKV strains (n = 11) belonged to the ECSA genotype whereas DENV-3 sequences (n = eight) clustered in Genotype III by phylogenetic analysis. Selection pressure of E1 protein of CHIKV and CprM protein of DENV-3 revealed purifying selection with four and two positive sites, respectively. Four amino acids of the CHIKV were positively selected and had high entropy suggesting probable variations. Co-circulation of both viruses in DENV endemic regions warrants effective monitoring of these emerging pathogens via comprehensive surveillance for implementation of effective control measures.

Prospective, population-based surveillance to systematically ascertain exposures to food production animals or their environments among Minnesota residents with sporadic, domestically acquired, laboratory-confirmed enteric zoonotic pathogen infections was conducted from 2012 through 2016. Twenty-three percent (n = 1708) of the 7560 enteric disease cases in the study reported an animal agriculture exposure in their incubation period, including 60% (344/571) of Cryptosporidium parvum cases, 28% (934/3391) of Campylobacter cases, 22% (85/383) of Shiga toxin-producing Escherichia coli (STEC) O157 cases, 16% (83/521) of non-O157 STEC cases, 10% (253/2575) of non-typhoidal Salmonella enterica cases and 8% (9/119) of Yersinia enterocolitica cases. Living and/or working on a farm accounted for 61% of cases with an agricultural exposure, followed by visiting a private farm (29% of cases) and visiting a public animal agriculture venue (10% of cases). Cattle were the most common animal type in agricultural exposures, reported by 72% of cases. The estimated cumulative incidence of zoonotic enteric infections for people who live and/or work on farms with food production animals in Minnesota during 2012–2016 was 147 per 10 000 population, vs. 18.5 per 10 000 for other Minnesotans. The burden of enteric zoonoses among people with animal agriculture exposures appears to be far greater than previously appreciated.

The relative contribution of imported vs. locally acquired infections to urban malaria burden remains largely unexplored in Latin America, the most urbanised region in the developing world. Here we use a simple molecular epidemiology framework to examine the transmission dynamics of Plasmodium vivax in Mâncio Lima, the Amazonian municipality with the highest malaria incidence rate in Brazil. We prospectively genotyped 177 P. vivax infections diagnosed in urban residents between June 2014 and July 2015 and showed that local parasites are structured into several lineages of closely related microsatellite haplotypes, with the largest genetic cluster comprising 32% of all infections. These findings are very unlikely under the hypothesis of multiple independent imports of parasite strains from the rural surroundings. Instead, the presence of an endemic near-clonal parasite lineage circulating over 13 consecutive months is consistent with a local P. vivax transmission chain in the town, with major implications for malaria elimination efforts in this and similar urban environments across the Amazon.

In the development of a surveillance programme for infectious diseases in Belgium, a national network of microbiological laboratories has been responsible, since February 1983, for the weekly registration of certain pathogenic agents. Thus, the main epidemiological features of a selected number of infections in Belgium can be characterized.