Characterizing hepatitis B virus infection in children in the Democratic Republic of Congo to inform elimination efforts.

Objective: Despite global reductions in hepatitis B virus (HBV) prevalence, an estimated 6.2 million children are infected, two-thirds of whom live in the WHO Africa region. We sought to characterize childhood HBV to inform elimination efforts in the Democratic Republic of Congo (DRC), one of the largest and most populous African countries. Methods: Using the most recent (2013-14) nationally representative Demographic and Health Survey in the DRC, we analyzed HBV surface antigen (HBsAg) on dried blood spots and associated survey data from children aged 6-59 months. We estimated HBsAg-positivity prevalence nationally, regionally, and by potential correlates of infection. We evaluated spatial variation in HBsAg-positivity prevalence, overall and by age, sex, and vaccination status. Findings: Using data from 5,679 children, we found national HBsAg-positivity prevalence was 1.3% (95% CI: 0.9%-1.7%), but ranged from 0.0% in DRC's capital city province, Kinshasa, to 5.6% in northwestern Sud-Ubangi Province. Prevalence among boys (1.8%, 95% CI: 1.2%-2.7%) was double that among girls (0.7%, 95%CI: 0.4%-1.3%). Tetanus antibody-negativity, rurality, and lower household wealth were also significantly associated with higher HBsAg-positivity prevalence. We observed no difference in prevalence by age. Children had higher HBsAg-positivity odds if living with ≥1 HBsAg-positive adult household member (OR: 2.3, 95%CI: 0.7-7.8), particularly an HBsAg-positive mother (OR: 7.2, 95%CI:1.6-32.2). Conclusion: In the largest national survey of HBV among children and household contacts in the DRC, we found that childhood HBV prevalence was 10-60 times the global target of 0.1%. We highlight specific regions and populations for further investigation and focused prevention efforts.

Successful Diagnosis of Intestinal Mycobacterium avium Complex Infection in a Kidney Transplant Recipient Using Nasogastric Aspirate Culture: A Case Report.

Intestinal Mycobacterium avium complex (MAC) infections are rare and can be challenging to diagnose. We describe a case of intestinal MAC infection in a kidney transplant recipient with 5 months of unexplained weight loss and abdominal pain who developed intestinal obstruction. Esophagoduodenoscopy with biopsies was performed but was nondiagnostic. Intestinal MAC was diagnosed via nasogastric aspirate culture results. The patient's symptoms rapidly improved after initiation of appropriate treatment, but he later died of aspiration pneumonia and candidemia.

Presumptive treatment of multidrug-resistant tuberculosis in household contacts.

SETTING: Multidrug-resistant tuberculosis (MDR-TB) is a growing global health threat that often requires presumptive treatment in the absence of drug susceptibility testing (DST) results. OBJECTIVE: To compare two approaches to the treatment of MDR-TB contacts with no DST results who develop TB disease. DESIGN: We conducted a retrospective cohort study of adults treated for TB disease who were contacts of patients living with MDR-TB. Subjects had been treated according to one of two presumptive treatment strategies: 1) regimens containing exclusively first-line drugs, and 2) regimens that included both first- and second-line drugs that were adjusted if and when DST results became available. The primary endpoint was a composite of death and treatment failure. RESULTS: Household contacts of MDR-TB patients who developed TB disease and were treated with first-line regimens were significantly more likely to experience unfavorable end-of-treatment outcomes than those treated with presumptive MDR-TB regimens (RR 2.88, 95%CI 1.24-6.68). CONCLUSION: Household contacts of MDR-TB patients who develop TB disease but have no DST results should receive regimens containing second-line drugs selected based on the infecting strain of the index patient. Regimens containing only first-line anti-tuberculosis drugs significantly increase the risk of unfavorable outcomes.

Metropolis or region: on the development and structure of London.

"Drawing on a disparate range of sources and viewing the question from several perspectives, an attempt is made to trace the development of London over the period since 1800. An account of the physical expansion and population growth is outlined, with ¿London' defined at a number of distinct scales. Attention is first focused on London as a metropolis, and various modelling techniques are used to illustrate the nature of metropolitan expansion. Consideration is given to the possibility that the changing spatial distribution of population through migration may be likened to a well-known process in physics. This is followed by an analysis of London at the broader scale of a region, with similar modelling techniques being employed. Finally, the question is raised as to whether London can still be meaningfully viewed as a metropolitan entity or whether a regional perspective is now more appropriate." (SUMMARY IN FRE AND GER)

Aspects of the lognormal function in the analysis of regional population distribution.

"The spatial structure of population within a metropolitan-area-based region is approached via the population density function, in much the same way as has been undertaken for a city or metropolitan area.... The concern in the balance of the paper is with certain properties lognormal form.... Consideration is given first to properties based on density. The population form of the lognormal function is then derived, and properties based on population are examined. Attention is also given to relationships among density-based and population-based properties." The approach is illustrated using data for London, England, for the period 1971-1981.

A note on the size distribution of cities over time.

"The Pareto Law of Income Distribution is applied to the analysis of city size structures. Particular concern is focused on the Pareto coefficient as a measure of interurban concentration, and on how this varies through time within a nation. On the basis of evidence from 12 nations, it is argued that over time a nation tends to display a U-shaped pattern in the degree of interurban concentration, and that the higher a nation's overall level of development, the more advanced it will be in the sequence of concentration. Consideration is given to the possibility of supporting these conclusions through cross-sectional analysis among nations. The various bases for the proposed temporal pattern of concentration within a nation are then explored."

City size distributions and urban density functions: some interrelationships.

This paper is concerned with "relating the apparent regularities of the population distribution within individual cities to the regularities with which the urban population of a nation is distributed among cities....An attempt is first made to draw the two distributions together in mathematical terms. The discussion then turns to a theoretical consideration of possible interrelations between the two distributions, after which the temporal variation of the parameters of each distribution is examined. This leads to the outlining of an evolutionary model of urban-system development, based on the passage through a number of stages." The analysis focuses on urban systems in Europe and North America.