Prevalence and Risk Factors of Lassa Seropositivity in Inhabitants of the Forest Region of Guinea: A Cross-Sectional Study

Lassa fever is a viral haemorrhagic fever endemic in West Africa, mainly transmitted to humans by multimammate rats. Several modes of virus transmission are suspected: aerosolisation of the virus, contact with infected rodent excreta, and consumption of rodent meat. Person-to-person transmission also occurs via contact with body fluids of infected persons (blood, urine) and is responsible for numerous outbreaks, mostly in healthcare facilities. Our objective was to precisely describe risk factors for Lassa fever in both rural and urban communities of forest Guinea. For each participant, a standardized questionnaire was completed and a blood sample tested for Lassa virus antibodies. A total of 1424 subjects were interviewed and 977 blood samples tested. The prevalence of Lassa virus antibodies was estimated at 12.9% and 10.0% in rural and urban areas, respectively. The two risk factors were: to have, in the past twelve months, undergone an injection, or lived with someone displaying a haemorrhage. Contrary to our expectation, no factors related to contact with rodents were identified. It is still probable that transmission occurs via indirect contact between rodents and humans in households, but our results highlight the importance of person-to-person transmission via close contact and nosocomial exposure

Increasing frailty is associated with higher prevalence and reduced recognition of delirium in older hospitalised inpatients: results of a multi-centre study

Purpose: Delirium is a neuropsychiatric disorder delineated by an acute change in cognition, attention, and consciousness. It is common, particularly in older adults, but poorly recognised. Frailty is the accumulation of deficits conferring an increased risk of adverse outcomes. We set out to determine how severity of frailty, as measured using the CFS, affected delirium rates, and recognition in hospitalised older people in the United Kingdom. Methods: Adults over 65 years were included in an observational multi-centre audit across UK hospitals, two prospective rounds, and one retrospective note review. Clinical Frailty Scale (CFS), delirium status, and 30-day outcomes were recorded. Results: The overall prevalence of delirium was 16.3% (483). Patients with delirium were more frail than patients without delirium (median CFS 6 vs 4). The risk of delirium was greater with increasing frailty [OR 2.9 (1.8–4.6) in CFS 4 vs 1–3; OR 12.4 (6.2–24.5) in CFS 8 vs 1–3]. Higher CFS was associated with reduced recognition of delirium (OR of 0.7 (0.3–1.9) in CFS 4 compared to 0.2 (0.1–0.7) in CFS 8). These risks were both independent of age and dementia. Conclusion: We have demonstrated an incremental increase in risk of delirium with increasing frailty. This has important clinical implications, suggesting that frailty may provide a more nuanced measure of vulnerability to delirium and poor outcomes. However, the most frail patients are least likely to have their delirium diagnosed and there is a significant lack of research into the underlying pathophysiology of both of these common geriatric syndromes

The prognostic utility of ultrasound in asymptomatic carotid disease

Atherosclerotic narrowing of the carotid arteries in asymptomatic individuals is associated with an increased risk of cerebrovascular ischemic events. The prevention of stroke in this context requires an understanding of the natural history of cerebrovascular atherosclerosis and the availability of an effective means for the detection and follow-up of carotid stenosis.Methodological standards for the conduct and reporting of natural history studies of asymptomatic carotid disease are proposed and used to carry out a structured methodological appraisal of the literature. The findings suggest that greater attention should be paid to the design and statistical analysis of natural history studies.A secondary analysis of the data from a natural history study of asymptomatic carotid disease is undertaken for the purpose of evaluating the prognostic usefulness of repeated duplex ultrasound examinations. Multivariable Cox proportional hazards models with fixed and time-dependent covariates are used to evaluate the predictive ability of carotid stenosis measurements obtained by duplex ultrasound at enrollment and during follow-up. The results of the analysis do not support the use of routine carotid ultrasound in clinical practice to determine prognosis for unselected patients with asymptomatic carotid disease

Hepatitis B infection is highly endemic in Uganda: findings from a national serosurvey

Background: Infant immunization against hepatitis B began in Uganda in 2002. Objective: To determine the baseline prevalence of hepatitis B virus (HBV) infection and explore risk factors. Methods: A hepatitis B prevalence study was nested in the 2005 national HIV/AIDS serobehavioural survey. Demographic characteristics and risk factors were explored by questionnaire. One third of blood specimens (n=5875) from adults aged 15 to 59 years were tested for hepatitis B core antibodies (HBcAb); positive specimens were tested for hepatitis B surface antigen (HBsAg). Results: HBcAb was present in 52.3% (95% CI: 51.0-53.6) of adults, and HBsAg in 10.3% (9.5-11.1). By 15-19 years of age, 40.0% had been infected with HBV. Prevalence of both markers was significantly higher across northern Uganda, in rural areas, among the poor and least educated, and in uncircumcised men. Other independent predictors of infection were age, ethnic group, occupation, number of sex partners, and HIV and HSV-2 status. Conclusion: Hepatitis B virus infection is highly endemic in Uganda, with transmission occurring in childhood and adulthood. More than 1.4 million adults are chronically infected and some communities disproportionately affected. The hepatitis B infant immunization programme should be sustained and catch-up vaccination considered for older children

Action for child survival: elimination of Haemophilus influenzae type b meningitis in Uganda

OBJECTIVE: To guide immunization policy, we determined the public health benefit of introducing Haemophilus influenzae type b (Hib) vaccine in Uganda and estimated the vaccine effectiveness. METHODS: Surveillance data for acute bacterial meningitis among children aged 0-59 months were reviewed from three hospital sentinel sites, for July 2001 to June 2007, to determine the incidence of Hib meningitis, the effectiveness of Hib vaccine with a case-control design, and the number of vaccine-preventable cases and deaths of Hib disease in Uganda. FINDINGS: Of the 13 978 children from 17 districts with suspected bacterial meningitis, 269 had confirmed Hib meningitis, declining from 69 patients in the prevaccine year (2001-2002) to three in 2006-2007. Hib meningitis incidence dropped from 88 cases per 100 000 children aged < 5 years in the year before vaccine introduction to 13 within 4 years, and to near zero in the fifth year. Vaccine effectiveness for 2 or more doses was 93% (95% confidence interval, CI: 69-99) against confirmed Hib meningitis and 53% (95% CI: 11-68) against purulent meningitis of unknown cause. In Uganda, Hib vaccine prevents an estimated 28 000 cases of pneumonia and meningitis, 5000 deaths and 1000 severe meningitis sequelae each year. CONCLUSION: Infant immunization with Hib vaccine has virtually eliminated Hib meningitis in Uganda within 5 years. Ensuring long-term benefits of Hib vaccine urgently requires sustainable vaccine financing, high-quality ongoing surveillance, and a health sector able to deliver a robust immunization programme

Yellow Fever in Africa: Estimating the Burden of Disease and Impact of Mass Vaccination from Outbreak and Serological Data

<div><p>Background</p><p>Yellow fever is a vector-borne disease affecting humans and non-human primates in tropical areas of Africa and South America. While eradication is not feasible due to the wildlife reservoir, large scale vaccination activities in Africa during the 1940s to 1960s reduced yellow fever incidence for several decades. However, after a period of low vaccination coverage, yellow fever has resurged in the continent. Since 2006 there has been substantial funding for large preventive mass vaccination campaigns in the most affected countries in Africa to curb the rising burden of disease and control future outbreaks. Contemporary estimates of the yellow fever disease burden are lacking, and the present study aimed to update the previous estimates on the basis of more recent yellow fever occurrence data and improved estimation methods.</p><p>Methods and Findings</p><p>Generalised linear regression models were fitted to a dataset of the locations of yellow fever outbreaks within the last 25 years to estimate the probability of outbreak reports across the endemic zone. Environmental variables and indicators for the surveillance quality in the affected countries were used as covariates. By comparing probabilities of outbreak reports estimated in the regression with the force of infection estimated for a limited set of locations for which serological surveys were available, the detection probability per case and the force of infection were estimated across the endemic zone.</p><p>The yellow fever burden in Africa was estimated for the year 2013 as 130,000 (95% CI 51,000–380,000) cases with fever and jaundice or haemorrhage including 78,000 (95% CI 19,000–180,000) deaths, taking into account the current level of vaccination coverage. The impact of the recent mass vaccination campaigns was assessed by evaluating the difference between the estimates obtained for the current vaccination coverage and for a hypothetical scenario excluding these vaccination campaigns. Vaccination campaigns were estimated to have reduced the number of cases and deaths by 27% (95% CI 22%–31%) across the region, achieving up to an 82% reduction in countries targeted by these campaigns. A limitation of our study is the high level of uncertainty in our estimates arising from the sparseness of data available from both surveillance and serological surveys.</p><p>Conclusions</p><p>With the estimation method presented here, spatial estimates of transmission intensity can be combined with vaccination coverage levels to evaluate the impact of past or proposed vaccination campaigns, thereby helping to allocate resources efficiently for yellow fever control. This method has been used by the Global Alliance for Vaccines and Immunization (GAVI Alliance) to estimate the potential impact of future vaccination campaigns.</p><p><i>Please see later in the article for the Editors' Summary</i></p></div

Geographical distribution of yellow fever occurrence and transmission.

<p>(A) Presence/absence of yellow fever over a 25-year period, by province. White, absence; red, presence of yellow fever reports. (B) Model predictions giving the estimated probability of at least one yellow fever report. (C) Estimates of the annual force of infection at the province level in the 32 countries considered endemic for yellow fever. (D) Estimates of the country-specific detection probability per infection. Countries not considered endemic for yellow fever are shown in navy (A, B, and D) or white (C).</p

Number of yellow fever vaccine doses procured for use in preventive vaccination campaigns from 2006 to 2012, percentage of the national population targeted and burden reduction achieved in 2013, by country.

a<p>Countries are ordered west to east.</p

Percentage of the all-cause mortality attributable to yellow fever by country.

<p>Grey bars indicate the point estimates, black lines the range spanned by the 95% CIs of the burden estimates. Countries are ordered west to east.</p