Epidemiology of chickenpox in England and Wales, 1967-85

Routine sources of data on chickenpox morbidity and mortality in England and Wales were reviewed for 1967-85. Only two epidemics occurred, one in 1967 and one in 1980, both of which were immediately followed by two to three years of low incidence. The age distribution of the disease appears to be changing, with more cases now being reported in children aged 0-4 years. The number of deaths in adults have, however, increased, particularly those deaths that are associated with pneumonia and immunosuppression. At present in England and Wales more deaths are attributed to chickenpox than to whooping cough and mumps.Widespread use of selective immunisation against chickenpox might be justified in England and Wales, but before routine immunisation of the child population can be considered special surveys to determine the incidence and severity of chickenpox and the effect of the vaccine on the subsequent development of herpes zoster are needed as well as cost-benefit studies of immunisation.     

Survey of sickle-cell disease in England and Wales.

The incidence and the clinical course of patients suffering from sickle-cell syndrome (Hb SS; Hb SC; Hb S thal) in England and Wales are not known. In 1979 an ad hoc committee was formed to investigate these problems. Initially, a questionnaire was sent to 227 haematologists in England and Wales to determine the number of cases in these countries. The replies have indicated that 1367 cases were seen in 1978 and 1979. Probably this may represent only half the total number of cases. From this survey it has been possible to draw up a composite map showing the location of patients, which has provided a basis to determine the clinical course of the disease, and for further studies into the complications and management of sickle-cell disease in England and Wales. From a second questionnaire preliminary data about the general management and mortality in England and Wales have been recorded.     

Honeybee viruses in Uruguay

Mortality of honeybees is a serious problem that beekeepers have to face periodically in Uruguay and worldwide. The presence of RNA viruses, in addition to other pathogens may be one of its possible causes. In this work, we detected Chronic bee paralysis virus, Acute bee paralysis virus, Black queen cell virus, Sacbrood virus and Deformed wing virus in samples of Uruguayan honeybees with or without Varroa destructor and Nosema apis. The detection of viruses in different provinces, simultaneous co-infection of colonies by several viruses and the fact that 96% of the samples were infected with one or more virus, indicates they are widely spread in the region.     

The prevalence of viruses of honey bees in Britain

Adult individuals of honey bee colonies in Britain are commonly infected with several small RNA viruses. Black queen cell virus and bee virus Y are the commonest and occur most frequently about June, together with Nosema apis with which both viruses are intimately but independently associated. Bee virus X is less common than bee virus Y and showed no pronounced seasonal fluctuations in local surveys, but was detected mostly in winter and early spring. Sacbrood virus occurred in adults of most local colonies in summer, chronic paralysis virus and cloudy wing particle occurred commonly but without seasonal variations and acute paralysis occurred commonly throughout the active season of bees but does not multiply sufficiently to cause overt disease. Slow paralysis virus was rare.     

Measles on the edge: coastal heterogeneities and infection dynamics

Mathematical models can help elucidate the spatio-temporal dynamics of epidemics as well as the impact of control measures. The gravity model for directly transmitted diseases is currently one of the most parsimonious models for spatial epidemic spread. This model uses distance-weighted, population size-dependent coupling to estimate host movement and disease incidence in metapopulations. The model captures overall measles dynamics in terms of underlying human movement in pre-vaccination England and Wales (previously established). In spatial models, edges often present a special challenge. Therefore, to test the model's robustness, we analyzed gravity model incidence predictions for coastal cities in England and Wales. Results show that, although predictions are accurate for inland towns, they significantly underestimate coastal persistence. We examine incidence, outbreak seasonality, and public transportation records, to show that the model's inaccuracies stem from an underestimation of total contacts per individual along the coast. We rescue this predicted 'edge effect' by increasing coastal contacts to approximate the number of per capita inland contacts. These results illustrate the impact of 'edge effects' on epidemic metapopulations in general and illustrate directions for the refinement of spatiotemporal epidemic models.     

The Honey Bee Pathosphere of Mongolia: European Viruses in Central Asia

Parasites and pathogens are apparent key factors for the detrimental health of managed European honey bee subspecies, Apis mellifera. Apicultural trade is arguably the main factor for the almost global distribution of most honey bee diseases, thereby increasing chances for multiple infestations/infections of regions, apiaries, colonies and even individual bees. This imposes difficulties to evaluate the effects of pathogens in isolation, thereby creating demand to survey remote areas. Here, we conducted the first comprehensive survey for 14 honey bee pathogens in Mongolia (N = 3 regions, N = 9 locations, N = 151 colonies), where honey bee colonies depend on humans to overwinter. In Mongolia, honey bees, Apis spp., are not native and colonies of European A. mellifera subspecies have been introduced ~60 years ago. Despite the high detection power and large sample size across Mongolian regions with beekeeping, the mite Acarapis woodi, the bacteria Melissococcus plutonius and Paenibacillus larvae, the microsporidian Nosema apis, Acute bee paralysis virus, Kashmir bee virus, Israeli acute paralysis virus and Lake Sinai virus strain 2 were not detected, suggesting that they are either very rare or absent. The mite Varroa destructor, Nosema ceranae and four viruses (Sacbrood virus, Black queen cell virus, Deformed wing virus (DWV) and Chronic bee paralysis virus) were found with different prevalence. Despite the positive correlation between the prevalence of V. destructor mites and DWV, some areas had only mites, but not DWV, which is most likely due to the exceptional isolation of apiaries (up to 600 km). Phylogenetic analyses of the detected viruses reveal their clustering and European origin, thereby supporting the role of trade for pathogen spread and the isolation of Mongolia from South-Asian countries. In conclusion, this survey reveals the distinctive honey bee pathosphere of Mongolia, which offers opportunities for exciting future research.     

Effect of Measles Vaccination on Incidence of Measles in the Community

A study of the effect of measles vaccination on the incidence of the disease in eight separate areas of England and Wales was begun in 1966. It showed an inverse association between the proportion of children vaccinated and the incidence of measles in the area in the following year, but measles epidemics occurred in several of the areas in subsequent years, despite continuing vaccinations.Measles vaccination was introduced on a large scale in Britain in 1968. Analysis of the notification and vaccination statistics shows that the vaccination of about 10% of the child population (under 15 years) in 1968 sufficed to “replace” the measles epidemic which had been expected in the period October 1968 to September 1969 by a low incidence of the disease, typical of that in previous “interepidemic” years. Further, the effect of the vaccinations was to prevent the development of natural measles in susceptible unvaccinated children as well as in the vaccinated subjects. Thus the number of immune subjects in the community was increased by the vaccinations, but as a result there was a reduction in the number of subjects who acquired immunity from natural measles. These opposed results can therefore explain why vaccination may be effective in the community for only a year or two, though vaccination protects the individual for much longer.It is estimated that a continuing vaccination rate of 40 to 50% of the children born each year would be necessary to replace the regular biennial measles epidemics in Britain by a continuous endemic incidence, and might perhaps lead to the disappearance of the disease without a further major epidemic, but that a continuing vaccination rate of 80 to 90% of children born each year would then be necessary to prevent its reintroduction. The long-term control of measles by vaccination will thus probably prove more difficult than for any other infectious disease.     

The effect of induced queen replacement on Nosema spp. infection in honey bee (Apis mellifera iberiensis) colonies

Microsporidiosis of adult honeybees caused by Nosema apis and Nosema ceranae is a common worldwide disease with negative impacts on colony strength and productivity. Few options are available to control the disease at present. The role of the queen in bee population renewal and the replacement of bee losses due to Nosema infection is vital to maintain colony homeostasis. Younger queens have a greater egg laying potential and they produce a greater proportion of uninfected newly eclosed bees to compensate for adult bee losses; hence, a field study was performed to determine the effect of induced queen replacement on Nosema infection in honey bee colonies, focusing on colony strength and honey production. In addition, the impact of long-term Nosema infection of a colony on the ovaries and ventriculus of the queen was evaluated. Queen replacement resulted in a remarkable decrease in the rates of Nosema infection, comparable with that induced by fumagillin treatment. However, detrimental effects on the overall colony state were observed due to the combined effects of stressors such as the queenless condition, lack of brood and high infection rates. The ovaries and ventriculi of queens in infected colonies revealed no signs of Nosema infection and there were no lesions in ovarioles or epithelial ventricular cells.     

Cities and villages: infection hierarchies in a measles metapopulation

An important issue in the dynamics of directly transmitted microparasites is the relationship between infection probability and host density. We use models and extensive spatio-temporal data for the incidence of measles to examine evidence for spatial heterogeneity in transmission probability, in terms of urban–rural hierarchies in infection rate. Pre-vaccination measles data for England and Wales show strong evidence for urban–rural heterogeneities in infection rate – the proportion of urban cases rises significantly before major epidemics. The model shows that this effect is consistent with a higher infection rate in large cities, though small towns have epidemic characteristics intermediate between town and country. Surprisingly, urban and rural areas of the same population size have a similar propensity for local extinction of infection. A spatial map of urban–rural correlations reveals complex regional patterns of synchronization of towns and cities. The hierarchical heterogeneities in infection persist into the vaccine era; their implications for disease persistence and control are discussed.     

Immune suppression in the honey bee (Apis mellifera) following infection by Nosema ceranae (Microsporidia)

Two microsporidia species have been shown to infect Apis mellifera , Nosema apis and Nosema ceranae . This work present evidence that N. ceranae infection significantly suppresses the honey bee immune response, although this effect was not observed following infection with N. apis . Immune suppression would also increase susceptibility to other bee pathogens and senescence. Despite the importance of both Nosema species in honey bee health, there is no information about their effect on the bees' immune system and present results can explain the different virulence between both microsporida infecting honeybees.     

Temporal analysis of the honey bee microbiome reveals four novel viruses and seasonal prevalence of known viruses, Nosema, and Crithidia

Honey bees (Apis mellifera) play a critical role in global food production as pollinators of numerous crops. Recently, honey bee populations in the United States, Canada, and Europe have suffered an unexplained increase in annual losses due to a phenomenon known as Colony Collapse Disorder (CCD). Epidemiological analysis of CCD is confounded by a relative dearth of bee pathogen field studies. To identify what constitutes an abnormal pathophysiological condition in a honey bee colony, it is critical to have characterized the spectrum of exogenous infectious agents in healthy hives over time. We conducted a prospective study of a large scale migratory bee keeping operation using high-frequency sampling paired with comprehensive molecular detection methods, including a custom microarray, qPCR, and ultra deep sequencing. We established seasonal incidence and abundance of known viruses, Nosema sp., Crithidia mellificae, and bacteria. Ultra deep sequence analysis further identified four novel RNA viruses, two of which were the most abundant observed components of the honey bee microbiome (～10(11) viruses per honey bee). Our results demonstrate episodic viral incidence and distinct pathogen patterns between summer and winter time-points. Peak infection of common honey bee viruses and Nosema occurred in the summer, whereas levels of the trypanosomatid Crithidia mellificae and Lake Sinai virus 2, a novel virus, peaked in January.     

Molecular and phylogenetic characterization of honey bee viruses,Nosema microsporidia,protozoan parasites,and parasitic mites in China

China has the largest number of managed honey bee colonies, which produce the highest quantity of honey and royal jelly in the world; however, the presence of honey bee pathogens and parasites has never been rigorously identified in Chinese apiaries. We thus conducted a molecular survey of honey bee RNA viruses, Nosema microsporidia, protozoan parasites, and tracheal mites associated with nonnative Apis mellifera ligustica and native Apis cerana cerana colonies in China. We found the presence of black queen cell virus (BQCV), chronic bee paralysis virus (CBPV), deformed wing virus (DWV), Israeli acute paralysis virus (IAPV), and sacbrood virus (SBV), but not that of acute bee paralysis virus (ABPV) or Kashmir bee virus (KBV). DWV was the most prevalent in the tested samples. Phylogenies of Chinese viral isolates demonstrated that genetically heterogeneous populations of BQCV, CBPV, DWV, and A. cerana‐infecting SBV, and relatively homogenous populations of IAPV and A. meliifera‐infecting new strain of SBV with single origins, are spread in Chinese apiaries. Similar to previous observations in many countries, Nosema ceranae, but not Nosema apis, was prevalent in the tested samples. Crithidia mellificae, but not Apicystis bombi was found in five samples, including one A. c. cerana colony, demonstrating that C. mellificae is capable of infecting multiple honey bee species. Based on kinetoplast‐encoded cytochrome b sequences, the C. mellificae isolate from A. c. cerana represents a novel haplotype with 19 nucleotide differences from the Chinese and Japanese isolates from A. m. ligustica. This suggests that A. c. cerana is the native host for this specific haplotype. The tracheal mite, Acarapis woodi, was detected in one A. m. ligustica colony. Our results demonstrate that honey bee RNA viruses, N. ceranae, C. mellificae, and tracheal mites are present in Chinese apiaries, and some might be originated from native Asian honey bees.     

High genetic variability of Nosema ceranae populations in Apis mellifera from East Asia compared to central Asia and the Americas

Biological Invasions - Nosema ceranae is believed to have been originally a parasite of the Asian honey bee, Apis cerana, in East Asia that later infected the Western honey bee, Apis mellifera,...     

Survival and immune response of drones of a Nosemosis tolerant honey bee strain towards N. ceranae infections

Honey bee colonies (Apis mellifera) have been selected for low level of Nosema in Denmark over decades and Nosema is now rarely found in bee colonies from these breeding lines. We compared the immune response of a selected and an unselected honey bee lineage, taking advantage of the haploid males to study its potential impact on the tolerance toward Nosema ceranae, a novel introduced microsporidian pathogen. After artificial infections of the N. ceranae spores, the lineage selected for Nosema tolerance showed a higher N. ceranae spore load, a lower mortality and an up-regulated immune response. The differences in the response of the innate immune system between the selected and unselected lineage were strongest at day six post infection. In particular genes of the Toll pathway were up-regulated in the selected strain, probably is the main immune pathway involved in N. ceranae infection response. After decades of selective breeding for Nosema tolerance in the Danish strain, it appears these bees are tolerant to N. ceranae infections.     

The incidence of dementia in England and Wales: findings from the five identical sites of the MRC CFA Study

BackgroundAlthough incidence of dementia is known to vary between nations, variation within country has not been explored because most incidence studies are single site or have insufficient numbers to compare sites. Few countries have conducted multisite incidence studies in order to facilitate national comparisons. This study aims to provide robust measures of the variation of the incidence of dementia across sites within England and Wales and produce overall estimates by age and sex.ConclusionThere is no evidence, within England and Wales, of variation in dementia incidence across sites. Dementia incidence rates do not tail off at the oldest ages.     

Wartime evacuation and mortality from childhood leukaemia in England and Wales in 1945-9.

OBJECTIVE--To discover whether the wartime government evacuation of children from London and other population centres to rural districts was associated with any increase in childhood leukaemia. DESIGN--Observational study of mortality from leukaemia among the childhood population of England and Wales in relation to the unique population movements during the second world war. The 476 rural districts of England and Wales were ranked according to the ratio of government evacuees (two thirds of them children) to local children in September 1941. The districts were divided into three categories, each with similar numbers of children in 1947 but with different ratios of evacuees to local children ("low," "intermediate," "high"). Mortality from childhood leukaemia was examined in these three rural categories in 1945-9. Urban areas were also examined according to their exposure to evacuees. SETTING--Local authority areas of England and Wales. SUBJECTS--Children aged under 15. RESULTS--47% excess of leukaemia at ages 0-14 years occurred in 1945-9 in the rural "high" category for evacuees relative to the "low" category, with a significant trend across the three categories. There were increases in both the 0-4 and 5-14 year age groups, but these were larger in the older age group. Rates 25% lower than average occurred in rural areas with few evacuees. CONCLUSION--These findings suggest that wartime evacuation increased the incidence of childhood leukaemia in rural areas and that other forms of population mixing may have contributed to the increases in past decades. Overall, they add to the appreciable evidence for an infective basis in childhood leukaemia.     

Detection of honey bee (Apis mellifera) viruses with an oligonucleotide microarray

In recent years, declines in honey bee (Apis mellifera L.) colonies have been observed to varying degrees worldwide with the worst losses in the USA being termed Colony Collapse Disorder (CCD). Pathogen load and the prevalence of honey bee viruses have been implicated in these losses and many diseased hives have multiple viruses present. We have designed and tested an oligonucleotide microarray which enables the simultaneous detection of nine honey bee viruses: Acute bee paralysis virus, Black queen cell virus, Chronic bee paralysis virus, Deformed wing virus, Kashmir bee virus, Sacbrood virus, Israel acute paralysis virus, Varroa destructor virus 1 and Slow paralysis virus. The microarray can be used to robustly diagnose nine viruses in one test.     

Control of hydatid disease in Wales.

OBJECTIVES--To evaluate the success of the south Powys hydatid control programme by analysis of trends in cystic disease in humans and sheep and dog infestation. DESIGN--A review of hospital admissions for human hydatid disease in 1984-90, abattoir prevalence surveys of hydatid cysts in adult sheep, arecoline acetarsol and coproantigen surveys of prevalence of Echinococcus infestation in dogs. SETTING--All hospitals in England and Wales, three abattoirs, and dog populations in mid ands south east Wales. SUBJECTS--Residents of England and Wales admitted to hospital between 1984 and 1990 with a new diagnosis of human hydatid disease (International Classification of Diseases (ICD), ninth revision, code 122) acquired in the United Kingdom. RESULTS--The average annual incidence of human hydatid disease in Powys, mid-Wales, fell from 3.9x10(-5) in 1974-83 to 2.3x10(-5) in 1984-90. Age specific incidence rates in Wales declined over this period only in children, and no cases occurred in children (<15 years) in Powys. Two Welsh children who lived in Gwent and mid-Glamorgan were infected. Prevalence of hydatid cysts in old sheep from south Wales declined during the control period, but in 1993 prevalence of cysts was 13%. Prevalence of E granulosus infestation was zero in the control area in 1993, but it was 2.4% in Powys dogs outside the control area in 1989 and 9.2% in dogs in Gwent in 1991. CONCLUSIONS--Human hydatid disease has been successfully controlled in south Powys but cystic echinococcosis is still endemic in sheep in mid-Wales, and there is a focus of infection in humans, sheep, and dogs in the bordering areas of Gwent and mid-Glamorgan. There is considerable potential for an upsurge in human cases if control measures are relaxed.