Utilising routine surveillance data, this study presents a method for generating a baseline comparison that can be used in future foodborne outbreak investigations following a case–case methodology. Salmonella and Campylobacter cases (2012–2015) from Maricopa County, AZ were compared to determine differences in risk factors, symptoms and demographics. For foods and other risk factors, adjusted odds ratios were developed using Campylobacter as the reference. Comparisons were also made for three major Salmonella subtypes, Typhimurium, Enteritidis and Poona as compared with Campylobacter. Salmonella cases were younger, while Campylobacter cases were more Hispanic and female. Campylobacter cases reported consuming peppers, sprouts, poultry, queso fresco, eggs and raw nuts more and reported contact with animal products, birds, visiting a farm or dairy, owning a pet, a sick pet, swimming in a river, lake or pond, or handling multiple raw meats more. Salmonella cases reported visiting a petting zoo and contact with a reptile more. There were significant variations by Salmonella subtype in both foods and exposures. We recommend departments conduct this analysis to generate a baseline comparison and a running average of relevant odds ratios allowing staff to focus on trace-back of contaminated food items earlier in the outbreak investigation process.

Little is known about HIV drug resistance (HIVDR) in newly diagnosed HIV-infected adults in eastern China where the HIV epidemic is spreading predominantly through sexual contact. During 2008–2011, newly HIV-diagnosed adults in Taizhou prefecture, Zhejiang province in eastern China were examined for HIVDR by amplifying and sequencing the HIV-1 pol gene. Of 447 genotyped participants, 53·7% were infected with CRF01_AE, 20·1% with CRF07_BC, 12·5% with subtype B, and 11·6% with CRF08_BC. Most of the participants had one or more minor genetic mutations in the pol gene that are associated with HIVDR. Twelve (2·7%) participants met the standard guidelines of having low to high HIVDR, suggesting that the prevalence of HIVDR in newly HIV-diagnosed adults was low in the study area and current antiretroviral therapy (ART) regimens are likely to remain effective. However, given high frequency of minor HIVDR in HIV patients and the scaling up of ART programmes in China, larger HIVDR surveillance programmes are needed.

Understanding patterns of influenza spread and persistence is crucial for pandemic preparedness. The H1N1pdm09 virus caused the first influenza pandemic of the 21st century which resulted in at least 18500 deaths. Based on laboratory-confirmed primary-care case reports we investigated the role of weather conditions and socio-demographic variables in its initial spread and subsequent presence in France. Our findings suggest that low relative humidity and high population density were determinants in shaping the early spread of the virus at the national level. Those conditions also favoured the persistence of viral presence throughout the first 33 weeks of the pandemic. Additionally this persistence was significantly favoured by low insolation. These results confirm the increasingly recognized role of humidity in influenza dynamics and underlie the concomitant effect of insolation. Therefore climatic factors should be taken into account when designing influenza control and prevention measures.

Dystrophies due to chronic fluorine poisoning in organs regulated by the parathyroid glands, namely the skin and its appendages, the nails, teeth and hair, and also in bones, are here shown to be unusually common in this country. They should be regarded as easily detectable signs of a serious disturbance of the calcium metabolism of the body. Fluorine is a poison of which the action, in many respects, is similar to that of arsenic. It is the task of the authorities responsible for the health of the nation to search for ways and means capable of minimizing its effect.

I wish to express my sincere thanks to the Librarian of the Royal Society of Medicine and his staff for their never-failing courtesy and help.

Influenza A antibodies in serum samples obtained in 1980 from two Indian populations in Central Brazil were compared. The Kren-Akorore, who were first contacted in 1973 and two years later transferred to the Xingu Indian Park (PIX), were compared with Indians from other tribes already living in the PIX before 1975. An analysis was made of the prevalence and distribution of antibodies against the influenza A viruses which have circulated in the civilized world since 1918. Antibodies to the early influenza A viruses were absent in both Indian populations, but A/Hong Kong/1/68 (H3N2) virus apparently circulated in the PIX. No antibody to influenza A/Bangkok/I/79 or to A/Brazil/11/78 (H1N1) was found in any of the sera, whereas antibodies to these viruses were commonly found in urban populations in Brazil. The evidence from influenza antibodies agrees with the information that the Kren-Akorore Indians had been living in complete isolation until 1973, when they were first contacted.

Chest CT evaluation is often vital to determine patients suspected of COVID-19 pneumonia. The aim of this study was to determine the evolution of lung abnormalities evaluated by quantitative CT techniques in patients with COVID-19 infection from initial diagnosis to recovery. This retrospective study included 16 patients with COVID-19 infection from 30 January 2020 through 11 March 2020. Repeat chest CT examinations were obtained for three or more scans per patient. We measured total volume and mean CT value of lung lesions in each patient per scan, and then calculated the mass, which equals to volume × (CT value + 1000). Dynamic evolution of chest CT imaging as a function of time was fitted by non-linear regression model in terms of mass, volume and CT value, respectively. According to the fitting curves, we redefined the evolution of lung abnormalities: progressive stage (0–5 days), infection emerged and rapidly aggravated; peak stage (5–15 days), the greatest severity at approximate 7–8 days after onset; and absorption stage (15–30 days), the lesions slowly and gradually resolved.

We update our previous insights into COVID-19 vaccine acceptance and hesitancy in Finland. Vaccine acceptance increased from 64% (November/December 2020) to 74% (April 2021). However, there was a group of participants that were preferring to wait to get vaccinated ranging from 6% of over-64-years-olds to 29% of under-30-years-olds. The previously identified enablers convenience (below-50-years-olds), worry about severe disease and protection for oneself (above-50-years-olds) were no longer significantly associated with increased vaccine acceptance. Understanding barriers and enablers behind vaccine acceptance is decisive in ensuring a successful implementation of COVID-19 vaccination programs, which will be key to ending the pandemic.

Both serological and bacteriological investigations revealed a cyclic, seasonal pattern of Yersinia enterocolitica 1B/O8 infections in Poland during the years 2008–2011. A large increase in incidence was observed in the second quarter and a decrease in the third quarter of each year. Such seasonal changes were not seen in the case of infections caused by the other enteropathogenic Yersinia bioserotypes.

The production of enterotoxin A and B by strains of Staphylococcus aureus isolated from nasal swabs of healthy carriers, from lesions of hospital patients and from foods unconnected with outbreaks of food-poisoning was investigated. Sixty-six strains of S. aureus were obtained from human beings, two produced enterotoxin A, 45 produced enterotoxin B. seven produced enterotoxins A + B. Thirty-six strains were isolated from 111 samples of food, one produced enterotoxin A, 16 produced enterotoxin B. The relative incidence of A, B and A + B enterotoxigenicity was assessed.

Four red cell antigen-antibody systems in the rabbit are described.

Three of these systems, Z, Y and W, appear to be inherited as an allelomorphic series. The fourth is inherited independently.

Some of the serological properties which allow these sera to be recognized are described and attention is drawn to a property of rabbit red cells, manifested by a variation in their susceptibility to agglutination by homologous antisera, which can complicate the separation of a mixture of antibodies in one serum.

The prevalence of scropositivity to Legionella spp. was studied in inmates and staff members of two geriatric hospitals (Rahel and Sinai); attendants to a geriatric Day Club; and 26 old people with entirely independent households. The sera were examined by indirect immunofluorescence with antigens of six Legionella species (L. pneumophila, L. longbeachae, L. micdadei, L. gormanii, L. dumoffii and L. bozemanii). A titre of ≥ 256 to at least one antigen was obtained in 30·5% of patients and 35·7% of staff members from Rahel; 12·1% of patients and 17·2% of staff members from Sinai; 9·1% of attendants to the Day Club; and none of 26 old people with their own households. All the positive patients from Rahel reacted with L. pneumophila, but only four of seven of the positive patients from Sinai did so; none of the seropositive subjects from the Day Club reacted with this agent.

The results indicate intramural exposure to agents of legionellosis, at least for the Rahel Hospital.

In spring 2009 a new strain of influenza A(H1N1) emerged and caused a worldwide pandemic. This study utilized a large collection of respiratory specimens from suspected cases of influenza A(H1N1) in the UK West Midlands during the pandemic in order to investigate which other respiratory viruses were circulating and whether they played any role in the increased hospitalization rates seen during that period. Study specimens were selected from community and hospitalized patients positive and negative for influenza A(H1N1) and tested by PCR for other respiratory viruses. A number of infections diagnosed as influenza during the summer influenza outbreak were found to be due to other virus infections (most commonly rhinovirus). No statistically significant difference was found between the rates of respiratory virus co-infection with H1N1 in patients from community or hospital locations suggesting underlying factors were likely to be more significant than viral co-infections in determining severity of influenza A(H1N1) disease.

The surveillance of Clostridium difficile (CD) in Denmark consists of laboratory based data from Departments of Clinical Microbiology (DCMs) sent to the National Registry of Enteric Pathogens (NREP). We validated a new surveillance system for CD based on the Danish Microbiology Database (MiBa). MiBa automatically collects microbiological test results from all Danish DCMs. We built an algorithm to identify positive test results for CD recorded in MiBa. A CD case was defined as a person with a positive culture for CD or PCR detection of toxin A and/or B and/or binary toxin. We compared CD cases identified through the MiBa-based surveillance with those reported to NREP and locally in five DCMs representing different Danish regions. During 2010–2014, NREP reported 13 896 CD cases, and the MiBa-based surveillance 21 252 CD cases. There was a 99·9% concordance between the local datasets and the MiBa-based surveillance. Surveillance based on MiBa was superior to the current surveillance system, and the findings show that the number of CD cases in Denmark hitherto has been under-reported. There were only minor differences between local data and the MiBa-based surveillance, showing the completeness and validity of CD data in MiBa. This nationwide electronic system can greatly strengthen surveillance and research in various applications.

Influenza A(H1N1) viruses of the 2009 pandemic (A(H1N1)pdm09) continue to cause outbreaks in the post-pandemic period. During January to May 2015, an upsurge of influenza was recorded that resulted in high fatality in central India. Genetic lineage, mutations in the hemagglutinin (HA) gene and infection by quasi-species are reported to affect disease severity. The objective of this study is to present the molecular and epidemiological trends during the 2015 influenza outbreak in central India. All the referred samples were subjected to qRT–PCR for diagnosis. HA gene sequencing (23 survivors and 24 non-survivors) and cloning were performed and analyzed using Molecular Evolutionary Genomic Analyzer (MEGA 5·05). Of the 3625 tested samples, 1607 (44·3%) were positive for influenza A(H1N1)pdm09, of which 228 (14·2%) individuals succumbed to death. A significant trend was observed in positivity (P = 0·003) and mortality (P < 0·0001) with increasing age. The circulating A(H1N1)pdm09 virus was characterized as belonging to clade-6B. Clinically significant mutations were detected. Patients infected with the quasi-species of the virus had a greater risk of death (P = 0·009). This study proposes a robust molecular and clinical surveillance program for the detection and characterization of the virus, along with prompt treatment protocols to prevent outbreaks.

The KwaZulu Natal and Eastern Cape provinces of South Africa have experienced a serious dog rabies epidemic over the past three decades. Towards a better understanding of this epidemic, we have previously analysed nucleotide sequences of 142 rabies virus specimens that were obtained from these regions during 2003–2004 and provided a molecular description of the geographical distribution of rabies viral variants in the affected provinces. Here, as an extension, we studied five human cases that occurred during 2002–2003 and demonstrated the use of the sequence database in tracking unknown human rabies case histories. We were able to identify the geographical origin of viruses responsible for each human infection and in one case obtained evidence that suggested a non-bite transmission of rabies virus from an infected dog to a child. We argue for the value of this information in surveillance and epidemiological study and in the follow-up and management of potential exposures.

Vaccinating monkeys against yellow fever (YF) has been a common practice in the beginning of the 17D vaccine development. Although it may seem strange at first sight, vaccinating monkeys as a public health strategy is, we think, feasible and theoretically could eliminate the infection among non-human primates, interrupting the virus circulation (or significantly reducing it) and therefore reducing the risk of spilling over to the human population. We propose a series of studies that could demonstrate (or not) the efficacy and feasibility of vaccinating non-human primates YF reservoirs living in green areas of urban centres to cut off or curb the virus circulation that recurrently spill over to the human population. Therefore, vaccinating monkeys in relatively small green areas of the urban centres is perhaps the ultimate solution for the Brazilian recurrent YF epizootics.

SARS-CoV-2 has severely affected capacity in the National Health Service (NHS), and waiting lists are markedly increasing due to downtime of up to 50 min between patient consultations/procedures, to reduce the risk of infection. Ventilation accelerates this air cleaning, but retroactively installing built-in mechanical ventilation is often cost-prohibitive. We investigated the effect of using portable air cleaners (PAC), a low-energy and low-cost alternative, to reduce the concentration of aerosols in typical patient consultation/procedure environments. The experimental setup consisted of an aerosol generator, which mimicked the subject affected by SARS-CoV-19, and an aerosol detector, representing a subject who could potentially contract SARS-CoV-19. Experiments of aerosol dispersion and clearing were undertaken in situ in a variety of rooms with two different types of PAC in various combinations and positions. Correct use of PAC can reduce the clearance half-life of aerosols by 82% compared to the same indoor-environment without any ventilation, and at a broadly equivalent rate to built-in mechanical ventilation. In addition, the highest level of aerosol concentration measured when using PAC remains at least 46% lower than that when no mitigation is used, even if the PAC's operation is impeded due to placement under a table. The use of PAC leads to significant reductions in the level of aerosol concentration, associated with transmission of droplet-based airborne diseases. This could enable NHS departments to reduce the downtime between consultations/procedures

Herpes simplex virus (HSV) is one of the most commonly identified infectious aetiologies of encephalitis in North America and Europe. The epidemiology of encephalitis beyond these regions, however, is poorly defined. During 2009–2012 we enrolled 313 patients in a multicentre prospective study of encephalitis in Peru, 45 (14·4%) of whom had confirmed HSV infection. Of 38 patients with known HSV type, 84% had HSV-1 and 16% had HSV-2. Patients with HSV infection were significantly more likely to present in the summer months (44·4% vs. 20·0%, P = 0·003) and have nausea (60·0% vs. 39·8%, P = 0·01) and rash (15·6% vs. 5·3%, P = 0·01) compared to patients without HSV infection. These findings highlight differences in the epidemiology and clinical presentation of HSV encephalitis outside of the Northern Hemisphere that warrant further investigation. Furthermore, there is an urgent need for improved HSV diagnostic capacity and availability of intravenous acyclovir in Peru.

One hundred and fifty-three water samples from rural Nicaragua were examined for the presence of faecal coliforms during both wet and dry periods. A linear model as fitted by analysis of covariance with the logarithm of the faecal coliform count as the dependant variable. As expected, traditional water sources were grossly contaminated at all times whereas piped water sources were much cleaner. Hand-dug protected wells had significantly higher levels of faecal contamination than unprotected riverside wells and springs during the dry season. The possible reasons for this unexpected finding are discussed. A close association between rainfall and faecal contamination was demonstrated but the effect of rainfall depended on the type of water source. An association between water quality and the size of the community served by the source was also detected. The finding that stored water was usually more contaminated than fresh water samples is consistent with the results from other studies. Since it is unusual for water quality to be inversely correlated wth accessibility, this study site would be suitable for investigating the relative importance of water-borne versus waterwashed transmission mechanisms in childhood diarrhoea.

(1) Inoculation of pathologically active crusts on guinea-pigs caused no reaction, and in this respect a marked difference was demonstrated clinically between the disease of which the crusts were a product, and vaccinia.

(2) On calves the disease tended to show some vaccino-variolal relationship, from the appearance of its vesicles, but it appeared to be distinct on the one hand from vaccinia, and from variola on the other.

(3) Calf experiments, two only in number, suggested that vaccinia and variola failed to protect against Australian disease, and that Australian disease failed to protect against vaccinia or variola.

(4) On monkeys the vesicles of Australian disease were undistinguishable in appearance from those of vaccinia or variola, but the evidence for immunity relationship between Australian disease and vaccinia and variola was of the slightest; Australian disease affording no protection against vaccinia or variola, vaccinia possibly protecting against Australian disease in 25 per cent, of the cases, and variola possibly protecting against Australian disease in 40 per cent, of the cases. Vaccinia protected against variola in 100 per cent, of the cases, and variola against vaccinia in 50 per cent, of the cases.