Seroconversion illness is known to be associated with more rapid HIV disease progression. However, symptoms are often subjective and prone to recall bias. We describe symptoms reported as seroconversion illness and examine the relationship between illness, HIV test interval (time between antibody-negative and anibody-positive test dates) and the effect of both on time to AIDS from seroconversion. We used a Cox model, adjusting for age, sex, exposure group and year of estimated seroconversion. Of 1820 individuals, information on seroconversion illness was available for 1244 of whom 423 (34%) reported symptomatic seroconversion. Persons with a short test interval ([les ]2 months) were significantly more likely to report an illness than people with a longer interval (OR 6·76, 95% CI 4·75–9·62). Time to AIDS was significantly faster (P=0·01) in those with a short test interval. The HIV test interval is a useful replacement for information on seroconversion illness in studies of HIV disease progression.

1. Myxomatosis was first recorded in England in October 1953 and persisted over the following winter. It was anticipated that an epizootic, similar to those in Australia, would develop during the spring or summer of 1954 and that mosquitoes might be the principal vectors. A study of the sylvan mosquitoes in the area of the first myxomatosis outbreak was therefore made, from April 1954 onwards.

2. These mosquitoes (Aëdes spp.) overwinter as larvae, pupate in early May and are adult from mid-May to September. Throughout this period, in 1954, myxomatosis spread slowly in the study area and infected rabbits were abundant.

3. Despite the presence of large numbers of Aëdes (particularly A. cartans and A. annulipes) and their persistent attacks upon man, the mosquitoes (except in one case) were not attracted to healthy domestic rabbits exposed in the woods. Aëdes can have little, if any, part in the spread of myxomatosis. Observations made in the cool summer of 1954 were confirmed in the hot summer of 1955.

4. Engorged mosquitoes (apart from those which had just fed on the human collector) were never found, so precipitin tests could not be made. The source from which these woodland mosquitoes normally obtain their blood meals remains a mystery.

5. In the laboratory, the Aëdes were reluctant to feed on normal, healthy rabbits but fed readily (round the eyes and on the nose) on normal anaesthetized rabbits or comatose myxomatous rabbits. Biting experiments indicated that Aëdes may remain infective for up to 36 days after an infective blood meal.

6. Infected Aëdes were recovered from woods containing myxomatous rabbits, and tame rabbits infected by the bites of these mosquitoes developed myxomatous tumours on the nose. Although some Aëdes were thus feeding on wild myxomatous rabbits, the evidence that the mosquitoes did not feed on healthy rabbits indicates that Aëdes were of negligible importance as vectors of myxomatosis.

Globally, twice as many men as women are being diagnosed with tuberculosis (TB) annually. Little is known about gender differentials in TB in Africa. A retrospective cohort analysis of routine data was conducted on adult TB patients treated between 2011 and 2012 in two large healthcare facilities in Nigeria. Gender differences in their demographic characteristics and treatment outcomes were analysed accordingly. Of 1668 TB patients enrolled, the male:female ratio was 1·4:1. The mean ages of males and females were 40·2 ± 14·7 and 36·1 ± 14·6 years, respectively (t test 6·62, P < 0·001). Male gender was associated with a higher failure to smear convert after 2 months (21·8% vs. 17·5%, P = 0·06) and 5 months (4·3% vs. 1·5%, P = 0·02) of treatment for smear-positive TB patients. Moreover, men were more likely than women to fail treatment (2·2% vs. 0·7%, P = 0·01). No significant differences exist in the treatment success rates between women and men (78·2% vs. 74·5%, P = 0·08). Adjusted analyses showed significant association between being an urban male and a HIV-infected female with unsuccessful outcome adjusted by socio-demographic and clinical factors. We found that gender disparities exist in TB profile and treatment outcomes in Nigeria and gender-specific strategies are needed to optimize TB management.

We obtained a list of all reported cases of haemorrhagic fever with renal syndrome (HFRS) in Shenyang, China, during 1990–2003, and used GIS-based scan statistics to determine the distribution of HFRS cases and to identify key areas and periods for future risk-factor research. Spatial cluster analysis suggested three areas were at increased risk for HFRS. Temporal cluster analysis suggested one period was at increased risk for HFRS. Space–time cluster analysis suggested six areas from 1995 to 1996 and four areas from 1998 to 2003 were at increased risk for HFRS. We also discussed the likely reasons for these clusters. We conclude that GIS-based scan statistics may provide an opportunity to classify the epidemic situation of HFRS, and we can pursue future investigations to study the likely factors responsible for the increased disease risk based on the classification.

Corynebacterium haemolyticum infections are described for the first time in Sri Lanka. In a period of 2 years from 1978–80 C. haemolyticum was isolated from the pharynx of 9 patients with tonsillitis and from local septic lesions in 7 other patients. Association with other pathogens was common. No patients had a rash. The properties of the isolates are described.

We report an outbreak of serious infections with Serratia marcescens in patients on a neurosurgery ward. The epidemiological investigations undertaken are described. Features of outbreaks of infection with serratia and control measures are discussed.

The incubation period during this epidemic was studied using both a spectral analysis-cum-filtering method and analysis of case histories. Using spectral analysis, the modal herd serial interval was estimated to be 8–10 days based on the record of the daily number of outbreaks and an adjusted cattle series. The case histories tended to confirm these estimates but indicated that the serial interval varied considerably between species. The filtering method revealed that the herd serial interval apparently changed during the epidemic. For the first 4 weeks the interval was 8 days, while in the latter stages it was about 2 weeks.

In areas in which plague is present, or has recently been present, in India, as an epidemic, no definite relation has been observed between intensity of plague (apart from its persistence), and badness of sanitary condition of dwellings. On the other hand, in areas in which plague is present endemically, so far as evidence goes, very unsatisfactory sanitary conditions exist. Such areas are generally situated in mountainous countries (Garhwal, Yunnan, Beni-Cheir, Transbaikalia). The inhabitants of such places, owing to the difficulty of obtaining water for domestic purposes, are apt to be filthy both in their houses and persons. In Garhwal, Yunnan, and Beni-Cheir domesticated animals are stabled in the houses, the paucity of level area making separate provision for cattle a matter of difficulty. Stable refuse consequently is liable to accumulate in the lower floors of the houses, producing conditions favourable to the presence of swarms of fleas.

Surveillance of new cases of invasive pneumococcal disease (IPD) in Italy was started in 2007 by the Ministry of Health (MoH). In 2012, pneumococcal childhood vaccination was introduced at the national level and, in 2017, for citizens aged 65 years and over. We describe here IPD epidemiology in Italy over the past 10 years investigating the impact of the vaccine programme on disease burden. Reports of IPD cases, data on serotype and vaccination coverage (VC) data were obtained from MoH annual reports, for the period 2007–2017. IPD notification rate and proportion by year, region, age and serotype were calculated. In 2007, 525 cases were reported (rate 0.88/100 000), rising to 1703 cases (rate 2.82/100 000) in 2017. The distribution of IPD cases by age group over time registered the largest share among individuals aged 65 years and over. A decreasing trend in notification rate was observed among those aged 0–4 years. During the same period, the 24-month VC increased, ranging from 80.9% to 96.7% in 2017. Molecular data indicated re-emergence of PPSV23-specific serotypes and non-vaccine serotypes. We observed an increase in IPD notifications during 2007–2017, likely due to an improved surveillance system, at least in some regions, with the relative quota of IPD notifications decreasing among vaccinated children cohorts. Further strengthening of IPD surveillance system, including molecular and vaccine coverage data, would be needed to assess and inform pneumococcal vaccination strategies in Italy.

The complement-fixation technique described in this paper was designed as a simple and rapid micro-method. It is derived from the method published by Fulton & Dumbell (1949), but a number of modifications have rendered it less laborious to perform and more flexible in application. Using rabbit, human and guinea-pig antisera, this technique has been successfully applied to the serological examination of the viruses of influenza, vaccinia and Newcastle disease, and experience with other materials, such as gonococcal antigen and extracts of chorio-allantoic membrane and mouse lung, suggests that it is of general application.

An outbreak of staphylococcal sepsis in a burns unit occurred between January 1976 and May 1978. Many patients and members of staff had boils, and a number of patients also developed septicaemia. Most of the boils in the early period of the trial and a large proportion of boils in patients during the later period yielded Staphylococcus aureus resistant to penicillin, tetracycline and erythromycin only (PTE), and were shown to be of phage type 95 in the early period while strains were phage typed. From blood cultures, most strains in the early period were of resistance pattern PTE and phage type 95, but in the later period other resistance patterns were predominant. Strains from burns were usually multiresistant (PTEKNML) and of the phage pattern 29/77, which had been endemic in the Unit, but during the early period of the outbreak there was an increased proportion of strains in burns with the resistance pattern PTE and of phage type 95.

Staphylococcal sepsis has for many years been very infrequent in the burns unit. This outbreak seems to have been initiated by a strain of phage type 95 and resistance pattern PTE, but during the course of the outbreak the endemic strain of type 29/77 and some other staphylococci seem to have developed enhanced ability to cause clinical infections, conceivably by transduction from the epidemic strain of phage type 95.

Sentinel herds at 34 farms were used to study the epidemiology of bluetongue and related orbiviruses in Oman. The results indicate that bluetongue virus (BTV) is widespread and is enzootic in Northern Oman. At least three BTV serotypes (3, 4 and 22) were present at the time of the study. Antibodies to epizootic haemorrhagic disease of deer virus (EHDV) type 2 and EHDV-318 were also detected but were less prevalent. Entomological investigations identified the presence of 16 species of Culicoides. The peak seasonal incidence of the BTV vector C. imicola and the EHDV vectors C. schultzei (group) midges at Rumais in Northern Oman correlated closely with the spring rains in that area. However, both species of midge were also present in lower numbers throughout the year. Four species of Omani midge, C. arabiensis, C. ibriensis, C. neoschultzei and C. buettikeri are new to science.

1. Dioxan when given intravenously and by stomach tube to guinea-pigs, rabbits and cats produces a state of drunken intoxication.

2. The minimum lethal dose for rabbits and cats is 1·5 c.c. per kg. intravenously and 2·0 c.c. per kg. by stomach tube.

3. Tolerance is rapidly acquired and recovery is complete after repeated sublethal doses.

4. In human beings lethal doses of dioxan produce primarily a necrosis of the intralobular arteries of the kidney with resulting necrosis of the parenchyma; whereas in laboratory animals, it has a selective action on the convoluted tubules, which undergo an acute hydropic degeneration, causing intrarenal obstruction and anuria with subsequent death from uraemia.

5. The so-called “necrosis” of the liver produced in rabbits with dioxan is a transitory phenomenon due to the presence of glycogen. This may be equally so in the “central zonal necrosis” seen in dioxan poisoning in human beings.

6. It is suggested that the toxicity of dioxan to human beings is relatively low and that large doses are required to produce lethal effects.

The virus growth in the pharyngeal area and the virus excretion in milk of susceptible and vaccinated dairy cows after intranasal instillation of foot-and-mouth disease (FMD) virus type O1 were examined. Ten vaccinated cows were purchased through a market. Of these, nine had delivered their first calf. The cows were inoculated 2–9 months after having received the last dose of vaccine. All vaccinated cows resisted the intranasal challenge. The virus multiplied in the pharyngeal area but, compared with two susceptible controls, to a limited extent. No clear relation was found between virus growth and the titre of circulating neutralizing antibody at the time of challenge.

Virus was first detected in milk samples of the susceptible cows when generalized FMD lesions had developed on day four; the excretion lasted for 3–4 days.

Up to 19 days after inoculation untreated milk of the vaccinated cows was examined for the presence of infectious FMD virus. Samples were inoculated onto cell cultures, fed to susceptible pigs and calves and injected intramuscularly and/or intradermolingually into susceptible steers. No infectious FMD virus could be detected, either in cell cultures or in susceptible animals. The animals did not develop neutralizing antibody against FMD virus and were subsequently shown to be fully susceptible to challenge. The results are discussed with particular reference to current problems regarding the export of milk products from countries where vaccination against FMD is practised to countries free of the disease.

Great strides have been made towards the control of poliomyelitis since the introduction of the two poliovaccines – inactivated poliovirus vaccine (IPV), which was licensed in the United States in 1954, and live attenuated oral poliovaccine (OPV), in 1961. Today a large majority of physicians and other health–care workers in industrialized countries never see a patient with paralytic poliomyelitis. Unfortunately, this is far from the situation in many developing countries, particularly in tropical and subtropical climates, where hundreds of thousands of children still become paralysed victims, year in and year out.

A sustained increase in Salmonella enterica serovar Virchow notifications in South Eastern Australia between September 1997 and May 1998 instigated a case-control study and environmental investigations. Cases were defined as having locally acquired culture-confirmed S. Virchow phage-type 8 infection and diarrhoeal disease. Matched controls were selected by progressive digit dialling based on cases' telephone numbers. An exposure and food history questionnaire was administered by telephone. Phage typing and pulse field gel electrophoresis were performed on case and environmental isolates. Thirty-two notifications of S. Virchow infection met the case definition, 37% reported bloody diarrhoea and S. Virchow was isolated from blood in 13% of cases. Twelve patients were admitted to hospital and one died. Fresh garlic (OR 4·1, 95% CI 1·3–12·8) and semi-dried tomatoes (OR 12·6, 95% CI 1·5–103·1) were associated with these cases. The associations remained significant after adjusting for sex and age. S. Virchow (PT 8) was cultured from two brands of semi-dried tomatoes associated with cases in two different states. We provide sufficient evidence for semi-dried tomatoes and fresh garlic to be considered as potential risk foods in future Salmonella outbreak investigations.

The present investigation deals with the routine bacteriological examination of 525 samples of water, 265 of which contained lactose fermenting bacilli; 1441 strains were isolated and various differential tests were used in the classification of these organisms.

All the strains were tested in dextrose phosphate culture for the methyl red and the Voges and Proskauer reactions, and although most of them gave normal results (M.R. + V.P. 0 or M.R. 0 V.P. +), there were 25 strains, 1·73 per cent., which gave either double positive or double negative reactions. Similar cases have already been discussed in an earlier portion of this paper, and they leave no doubt that there are types which may vary from the normal as far as the methyl red and the Voges and Proskauer reactions are concerned. At the same time these abnormal types are not sufficiently numerous to make any real practical difficulties in the use of these tests for routine purposes.

The Koser test, considered by many bacteriologists to be of great differential value, was found to give imperfect correlation with the other reactions.

1395 strains were isolated which could be classified in the B. coli group as a result of the production of acid and gas in lactose, the clotting of milk, and the non-liquefaction of gelatine, but when the methyl red and the Voges and Proskauer results were considered it was found that nearly 11 per cent. of these strains were of the B. lactis aerogenes type, and were therefore of no value as indicators of faecal pollution.

The indol reactions were somewhat variable. Among 1244 strains of the B. coli type (M.R. + V.P. 0), more than 10 per cent. failed to produce indol; while among 151 strains of the B. lactis aerogenes type (M.R. 0 V.P. +), nearly 51 per cent. were indol producers. Preliminary extraction with ether was carried out with 448 of these strains before Böhme's reagent was added. With this technique it was found that among 400 methyl red positive types there were 87 strains (22 per cent.) which produced no indol, and among 48 methyl red negative strains there were 12 (25 per cent.) which gave the reaction. Chen and Rettger (1920) were unable to establish any definite correlation between the indol test and the other reactions.

When the sample results were studied, it was found that although 262 waters contained organisms which were included in the B. coli group on the basis of the lactose, milk and gelatine tests, nearly 6 per cent. of these samples contained only organisms which gave a methyl red negative, Voges and Proskauer positive reaction, and were probably associated with pollution from soil washings rather than contamination from faecal sources. This means that the application of the methyl red and Voges and Proskauer reaction does make a considerable practical difference in the interpretation of results in the bacteriological examination of water.

More detailed examination as regards the fermentation of the various carbohydrates is useful for purposes of classification, but is of no significance, in the light of our present knowledge, in assessing the probability of excretal pollution.

It is suggested that, in considering the results of a bacteriological examination of water, organisms should be regarded as significant which are of typical morphology and staining reaction, produce acid and gas in lactose, fail to liquefy gelatine, clot milk, and give a positive methyl red and a negative Voges and Proskauer reaction. The production of indol in a medium containing peptone may be added as an extra test if desired, but the available evidence does not suggest that failure to produce indol is a sufficient basis for the exclusion of an otherwise typical bacillus from the B. coli group.

My thanks are due to Dr G. D. Dawson, in conjunction with whom the present investigation was started; and also to Prof. W. W. C. Topley whose interest throughout the course of the research was made manifest by his helpful advice and criticism.

Currently no national guidelines exist for the management of scabies outbreaks in residential or nursing care homes for the elderly in the United Kingdom. In this setting, diagnosis and treatment of scabies outbreaks is often delayed and optimal drug treatment, environmental control measures and even outcome measures are unclear. We undertook a systematic review to establish the efficacy of outbreak management interventions and determine evidence-based recommendations. Four electronic databases were searched for relevant studies, which were assessed using a quality assessment tool drawing on STROBE guidelines to describe the quality of observational data. Nineteen outbreak reports were identified, describing both drug treatment and environmental management measures. The quality of data was poor; none reported all outcome measures and only four described symptom relief measures. We were unable to make definitive evidence-based recommendations. We draw on the results to propose a framework for data collection in future observational studies of scabies outbreaks. While high-quality randomised controlled trials are needed to determine optimal drug treatment, evidence on environmental measures will need augmentation through other literature studies. The quality assessment tool designed is a useful resource for reporting of outcome measures including patient-reported measures in future outbreaks.

The pandemic of coronavirus disease 2019 (COVID-19) has posed serious challenges. It is vitally important to further clarify the epidemiological characteristics of the COVID-19 outbreak for future study and prevention and control measures. Epidemiological characteristics and spatial−temporal analysis were performed based on COVID-19 cases from 21 January 2020 to 1 March 2020 in Shandong Province, and close contacts were traced to construct transmission chains. A total of 758 laboratory-confirmed cases were reported in Shandong. The sex ratio was 1.27: 1 (M: F) and the median age was 42 (interquartile range: 32–55). The high-risk clusters were identified in the central, eastern and southern regions of Shandong from 25 January 2020 to 10 February 2020. We rebuilt 54 transmission chains involving 209 cases, of which 52.2% were family clusters, and three widespread infection chains were elaborated, occurring in Jining, Zaozhuang and Liaocheng, respectively. The geographical and temporal disparity may alert public health agencies to implement specific measures in regions with different risk, and should attach importance on how to avoid household and community transmission.

Unidentified open-air factors (OAFs) found to be adverse to the survival of microorganisms suspended on microthreads were investigated for their effect on realistic aerosols of Francisella tularensis in an open-air environment. This organism was chosen because it is probably the most infectious organism known to be capable of infecting both animals and man via the respiratory route, hence its potential use as a bioterrorist agent. A direct correlation was found between an open-air adverse effect on viability and virulence of airborne particles of <3 μm via the respiratory route in guinea pigs. One viable organism was sufficient to initiate an infection that resulted in a fatal tularaemia infection. The lethal effect of OAFs on F. tularensis was found to vary from day to day and was related to the source of the air in the UK. The adverse effect on viability was associated with an inverse effect according to the size of the airborne particle.