Spatial growth rate of emerging SARS-CoV-2 lineages in England, September 2020-December 2021.

This paper uses a robust method of spatial epidemiological analysis to assess the spatial growth rate of multiple lineages of SARS-CoV-2 in the local authority areas of England, September 2020-December 2021. Using the genomic surveillance records of the COVID-19 Genomics UK (COG-UK) Consortium, the analysis identifies a substantial (7.6-fold) difference in the average rate of spatial growth of 37 sample lineages, from the slowest (Delta AY.4.3) to the fastest (Omicron BA.1). Spatial growth of the Omicron (B.1.1.529 and BA) variant was found to be 2.81× faster than the Delta (B.1.617.2 and AY) variant and 3.76× faster than the Alpha (B.1.1.7 and Q) variant. In addition to AY.4.2 (a designated variant under investigation, VUI-21OCT-01), three Delta sublineages (AY.43, AY.98 and AY.120) were found to display a statistically faster rate of spatial growth than the parent lineage and would seem to merit further investigation. We suggest that the monitoring of spatial growth rates is a potentially valuable adjunct to outbreak response procedures for emerging SARS-CoV-2 variants in a defined population.

Operation Pied Piper: a geographical reappraisal of the impact of wartime evacuation on scarlet fever and diphtheria rates in England and Wales, 1939-1945.

This paper examines the geographical impact of the British Government's wartime evacuation scheme on notified rates of two common acute childhood diseases (scarlet fever and diphtheria) in the 1470 local government districts of England and Wales, 1939-1945. Drawing on the notifications of communicable diseases collated by the General Register Office (GRO), we establish pre-war (baseline) disease rates for the 1470 districts. For the war years, techniques of binary logistic regression analysis are used to assess the associations between (a) above-baseline ('raised') disease rates in evacuation, neutral and reception districts and (b) the major phases of the evacuation scheme. The analysis demonstrates that the evacuation was temporally associated with distinct national and regional effects on notified levels of disease activity. These effects were most pronounced in the early years of the dispersal (1939-1941) and corresponded with initial levels of evacuation-related population change at the regional and district scales.

Abrupt transition to heightened poliomyelitis epidemicity in England and Wales, 1947-1957, associated with a pronounced increase in the geographical rate of disease propagation.

The abrupt transition to heightened poliomyelitis epidemicity in England and Wales, 1947-1957, was associated with a profound change in the spatial dynamics of the disease. Drawing on the complete record of poliomyelitis notifications in England and Wales, we use a robust method of spatial epidemiological analysis (swash-backwash model) to evaluate the geographical rate of disease propagation in successive poliomyelitis seasons, 1940-1964. Comparisons with earlier and later time periods show that the period of heightened poliomyelitis epidemicity corresponded with a sudden and pronounced increase in the spatial rate of disease propagation. This change was observed for both urban and rural areas and points to an abrupt enhancement in the propensity for the geographical spread of polioviruses. Competing theories of the epidemic emergence of poliomyelitis in England and Wales should be assessed in the light of this evidence.

Spatiotemporal patterns of pandemic influenza-related deaths in Allied naval forces during 1918.

This paper draws on the mortality records of the French, US and UK Royal navies to reconstruct the spatiotemporal evolution of the 1918­1919 influenza pandemic in global Allied naval forces. For a total of 7658 deaths attributed to respiratory diseases (French and US navies) and all diseases (UK Royal Navy) at 514 locations worldwide, techniques of spatial point pattern analysis were used to generate weekly maps of global mortality intensity in 1918. The map sequence for the main period of pandemic mortality, mid-August to mid-November 1918, revealed a near-simultaneous development of mutiple foci of high disease intensity in three distant locations (Europe, North America, West Africa). Given the relatively slow speed of naval ships in convoy at this time (<12 knots), our findings suggest that the pandemic influenza virus was circulating on three continents at the observed onset of the main mortality wave.

Common acute childhood infections and appendicitis: a historical study of statistical association in 27 English public boarding schools, 1930-1934.

Although the involvement of common childhood infections in the aetiology of acute appendicitis has long been conjectured, supporting evidence is largely restricted to a disparate set of clinical case reports. A systematic population-based analysis of the implied comorbid associations is lacking in the literature. Drawing on a classic epidemiological dataset, assembled by the School Epidemics Committee of the United Kingdom's Medical Research Council (MRC) in the 1930s, this paper presents a historical analysis of the association between termly outbreaks of each of six common childhood infections (chickenpox, measles, mumps, rubella, scarlet fever and whooping cough) and operated cases of acute appendicitis in 27 English public boarding schools. When controlled for the potential confounding effects of school, year and season, multivariate negative binomial regression revealed a positive association between the level of appendicitis activity and the recorded rate of mumps (beta=0.15, 95% CI 0.07-0.24, P<0.001). Non-significant associations were identified between appendicitis and the other sample infectious diseases. Subject to data caveats, our findings suggest that further studies are required to determine whether the comorbid association between mumps and appendicitis is causal.

Breast cancer incidence and its possible spatial association with pesticide application in two counties of England.

BACKGROUND: This study examines the spatial distribution of breast cancer incidence in Lincolnshire and Leicestershire, and its association with the application of selected pesticides. METHODS: The Black-White (BW) join-count statistic and Moran I coefficient were used to investigate the localized distribution of breast cancer. Linear regression techniques were applied to examine the association between the breast cancer incidence rate and pesticide application. RESULTS: The results from the BW join-count test and the Moran I coefficient test showed no overall evidence of localized distribution, 'clusters', of breast cancer. The regression analyses showed no sign of spatial association between breast cancer and application of pesticides in the urban areas as expected. The findings, however, did reveal a spatial association between the breast cancer incidence rates and the application of three selected pesticides [Aldicarb, Atrazine and Lindane (thought to potentially mimic oestrogen)] in rural Leicestershire. No such association was seen in Lincolnshire. CONCLUSIONS: Pesticides vary significantly in their spatial application. Overall, consistent associations between breast cancer incidence rates and the selected pesticides were not found, although the ecological study design has limitations and these are discussed. This approach is able to rule out strong associations; assessment of smaller risk would require a large and expensive study in individuals. The results of this study, although derived in the UK, have significance to the debate concerning the possibility of environmental compounds that mimic oestrogen and their consequences for human health.

Spatial and temporal patterns in final amendments to provisional disease counts.

This article examines temporal and spatial patterns in the relationship between provisional and amended reports for Hepatitis A and Hepatitis B received from each state by the Centers for Disease Control and Prevention through the U.S. National Notifiable Diseases Surveillance System from 1980 to 1992. It demonstrates that, as the 1980s unfolded, the preliminary disease reports became less representative markers of final disease counts. Practitioners at the state and community levels need to be aware of the temporal and spatial instabilities in such provisional data if they are used to provide early warning of contemporary health aberrations.

Late stages of epidemiological transition: health status in the developed world.

Drawing on the example of twentieth century Europe, this paper examines themes in the spatial development of the late stages of epidemiological transition in developed countries. A preliminary analysis of mortality trends for sample countries in four European regions (north, Scandinavia, south and east) suggests that, as the epidemiological transition progressed to its later stages during the period 1901-1975, spatial variability in the importance of classical infectious diseases increased. This trend was countered by a spatial convergence in the importance of disease groupings that typify late transition. An apparently new epidemiological phase in late transition, linked to the emergence and re-emergence of infectious and parasitic diseases, is illustrated with reference to tuberculosis and the acquired immunodeficiency syndrome (AIDS).

Atopic eczema and domestic water hardness.

BACKGROUND: The environment plays an important part in the aetiology of atopic eczema, but specific causes are unknown. Exposure to hard water is thought to be a risk factor for eczema. We undertook an ecological study of the relation between domestic water hardness and the prevalence of eczema among Nottinghamshire schoolchildren. METHODS: Questionnaire details of 1-year period and lifetime prevalence of eczema were obtained from parents of 4141 randomly selected primary-school children and 3499 secondary-school children in southern Nottinghamshire. Geographical information systems (GIS) were used to link the geographical distribution of eczema prevalence with domestic water-hardness data (four categories). Adjustment was made for potential confounding by sex, age, socioeconomic status, and access to health care. FINDINGS: Among the primary-school children there was a significant direct relation between both 1-year period and lifetime prevalence of eczema and water hardness, both before and after adjustment for confounders. The 1-year period prevalence was 17.3% (261/1509) in the highest water-hardness category and 12.0% (94/786) in the lowest (adjusted odds ratio 1.54 [95% CI 1.19-1.99] p for trend <0.001). The corresponding values for lifetime prevalence were 25.4% (384/1509) and 21.2% (167/786; adjusted odds ratio 1.28 [1.04-1.58], p for trend=0.02). Eczema prevalence trends in the secondary-school population were not significant (adjusted odds ratio for highest compared with lowest hardness category for 1-year prevalence 1.03 [0.79-1.33], p for trend=0.46; for lifetime prevalence 0.99 [0.83-1.23], p for trend=0.93). Eczema prevalence in primary-school children increased in relation to chlorine content of water, but the trend across four chlorine-content categories was not independently significant after adjustment for confounders. INTERPRETATION: Exposure to hard water in the home may increase the risk of eczema in children of primary-school age.

The geographical assignment of cancer units: patient accessibility as an optimal allocation problem.

The seminal report A Policy Framework for Commissioning Cancer Services provides the foundation for a major reorganisation of cancer service provision in England and Wales. One central recommendation of the report, the establishment of a tier of specialised cancer units in each Health Authority Region has raised the fundamental question of where those units are to be located. In particular, a declared objective of the report is for services to be planned to maximise their accessibility to patients. This paper demonstrates a classical method (location-allocation modelling) by which the accessibility criterion can be used to determine the optimal number, location and capacity of units for a given cancer site. The method is illustrated with reference to cervical cancer in Trent Health Authority Region. The implications of the method for the guidance of access-related decisions on the placement of cancer services are considered, and the wider relevance of the method to the organisation of service provision in other branches of medicine is suggested.

The importance of long-term records in public health surveillance: the US weekly sanitary reports, 1888-1912, revisited.

BACKGROUND: This paper outlines the ways in which a little-used archive of early public health records may throw light on longer-term trends in international epidemic behaviour and serve as a major source of epidemiological information for historians of urbanization and public health. The Weekly Abstract of Sanitary Reports was the official disease surveillance report of the US Public Health Service and its predecessors, and began to publish urban mortality statistics on a regular basis in 1888. Here, the authors describe the first 25 years of continuous reporting (1888-1912), when the Reports contained not only disease data for US cities, but also records sent back by US consuls based in some 250 cities in many parts of the world. METHODS: The content of the weekly editions of the Reports was systematically sampled and analysed using graphical techniques and the simple statistical method of running means. RESULTS: Relatively complete weekly series of mortality from all causes, and six infectious diseases (diphtheria, enteric or typhoid fever, measles, scarlet fever, tuberculosis and whooping cough) were identified for a total of 100 cities world-wide. CONCLUSION: Reporting coverage for these cities is sufficiently complete that multivariate analysis should be possible to obtain a comparative picture of mortality for many parts of the world. Despite limitations of the data, sources of the type described in this paper form an important comparative database for studying international patterns of mortality.

The application of multidimensional scaling methods to epidemiological data.

This paper illustrates the use of multidimensional scaling methods (MDS) to examine space-time patterns in epidemic data. The paper begins by outlining the principles of MDS. The model is then formally specified and illustrated by application to two data sets. The first is partly a tutorial example. It uses monthly reported measles morbidity data for the 31-year period from January 1960 to December 1990, collected for the 50 states of the USA, plus New York City and the District of Columbia. These data are used to explore the various ways in which MDS may be used to identify changing spatial patterns in geographically-coded data. In addition to their tutorial use, the data are also employed to search for any substantive changes in the geographical structure of measles epidemics in the USA that may have followed the introduction of mass vaccination in 1965. New England appears to have developed an epidemic profile distinct from the rest of the USA, and there is tentative evidence of an urban-rural split in epidemic characteristics. The second data set takes annual reported measles mortality data for New Zealand and the states of Australia from 1860 to 1949. MDS is used to show how the spatial relationships among these geographical units have changed over time in response to changes in the sizes of local susceptible populations.

Seasonality in tropical AIDS: a geographical analysis.

This paper presents evidence that the growth rate of the AIDS epidemic at the district level in Uganda, Central Africa, displays a seasonally recurring geographical pattern, with epidemic acceleration in some areas of the country in the first 8 months of each year. The spatial and temporal variations in acceleration appear to be correlated with the predominant agricultural systems in different parts of Uganda. Based upon the frequently hypothesized relationship between malnourishment and the progression to clinical AIDS in HIV-infected people, it is suggested that the variations in epidemic speed reflect the seasonal patterns of nutritional deficiency which occur under some tropical agricultural systems. These preliminary findings require further verification since they have important implications for directing nutrition-related remedial responses to the AIDS epidemic in tropical countries where malnutrition and endemic HIV infection coincide.

PIP: Human geographers applied data of 12,444 cases of AIDS in Uganda diagnosed between January 1986-December 1989 to a statistical methodology used in geography to see if AIDS exhibits seasonal rhythms. The analysis revealed that seasonally recurring geographical patterns were the basis for the velocity of reported AIDS epidemics in different districts of Uganda (p.05). Epidemic acceleration was most evident in all regions of Uganda, except the Central region. The AIDS epidemic patterns paralleled the seasonal rhythms of agricultural production. In the Central region, crop production was perennial. Thus food was always available which may account for no apparent AIDS epidemic pattern in this region. On the other hand, pastoral activity and annual arable crop production predominated in the Eastern region where constant fluctuations in AIDS incidence occurred. In fact, people store foodstuffs and stocks wane towards the harvest in August, September, and October. The Western and Northern regions exhibit basically the same patterns. These observations suggested a correlation between nutritional deficiencies and progression of AIDS as often occurs with other infections under some tropical agricultural systems. This study appeared to be the 1st study to document statistical significance of a possible seasonally recurring component to the diagnosis of clinical AIDS in a tropical country. Additional research is needed to determine whether this seasonal pattern is due to insufficient data quality or an association with malnutrition does indeed exist.

Civil war and the spread of AIDS in Central Africa.

Using ordinary least squares regression techniques this paper demonstrates, for the first time, that the classic association of war and disease substantially accounts for the presently observed geographical distribution of reported clinical AIDS cases in Uganda. Both the spread of HIV 1 infection in the 1980s, and the subsequent development of AIDS to its 1990 spatial pattern, are shown to be significantly and positively correlated with ethnic patterns of recruitment into the Ugandan National Liberation Army (UNLA) after the overthrow of Idi Amin some 10 years earlier in 1979. This correlation reflects the estimated mean incubation period of 8-10 years for HIV 1 and underlines the need for cognizance of historical factors which may have influenced current patterns of AIDS seen in Central Africa. The findings may have important implications for AIDS forecasting and control in African countries which have recently experienced war. The results are compared with parallel analyses of other HIV hypotheses advanced to account for the reported geographical distribution of AIDS in Uganda.

PIP: Statistical analyses suggest that military involvement has substantially affected the apparent geographical distribution of reported clinical AIDS cases in Uganda. Official estimates place the number of HIV infections in Uganda at 1 million, 6% of the country's population. Using statistical regression model, the authors test the viability of 3 hypotheses in explaining the geographical distribution of the epidemic: 1) the "truck town hypothesis," which proposes that the distribution of HIV and AIDS reflects the diffusion process in which major roads act as the main corridors of virus spread; 2) the "migrant labor hypothesis," which says that HIV spread from areas of labor demand in urban regions to areas of labor supply in rural regions through return migration; and 3) the "military involvement" hypothesis, which takes into account the historical link between servicemen, prostitutes, and the spread of STDs. The military involvement hypothesis proposes that the distribution of HIV is largely due to the 6-year civil war that began in Uganda in 1979, following the overthrow of Idi Amin. As the statistical regression shows, the truck town hypothesis and the migrant labor hypothesis fail to fully explain the district to district variability in AIDS incidence. The analysis, however, does reveal a highly significant positive relationship between the ethnic composition of the Ugandan National Liberation Army and the currently reported spatial pattern of clinical AIDS in the country, which makes sense, considering that the mean incubation period for HIV is estimated at 8-10 years. The authors note that these findings may serve to in forecasting and controlling the spread of AIDS in other African countries which have recently experience war.

The spread of human immunodeficiency virus type 2 into Europe: a geographical analysis.

Geographically-related computer databases on the global incidence of HIV-1 and HIV-2 infection are being maintained in the Department of Geography at the University of Cambridge, England. Using the information they contain, the original geographical heartlands of HIV-2 infection are identified as former Portuguese and French colonies in West and South Central Africa. The same databases permit the reconstruction of the diffusion corridors by which the virus is spreading from these heartlands into Europe. The reconstruction shows that, as a result of traditional links with their former colonies, the main areas of infection in Europe are Portugal and France. These countries have subsequently acted as diffusion nodes for the spread of the virus to other parts of Europe. The patterns of spread thus differ fundamentally from those by which HIV-1 infection arrived in and is moving through Europe.