• Colombia: The Winner Takes All.

      Veeken, H; Medecins Sans Frontières, PO Box 10014, 1001 EA Amsterdam, Netherlands. hansvveeken@amsterdam.msf.org (Published by: BMJ Publishing Group Ltd, 1998-12-12)
    • Ecological study of socio-economic indicators and prevalence of asthma in schoolchildren in urban Brazil.

      da Cunha, S S; Pujades-Rodriguez, M; Barreto, M L; Genser, B; Rodrigues, L C; Instituto de Saúde Coletiva, Universidade Federal de Bahia, Salvador, Brazil. cunhass@ufba.br (2007)
      BACKGROUND: There is evidence of higher prevalence of asthma in populations of lower socio-economic status in affluent societies, and the prevalence of asthma is also very high in some Latin American countries, where societies are characterized by a marked inequality in wealth. This study aimed to examine the relationship between estimates of asthma prevalence based on surveys conducted in children in Brazilian cities and health and socioeconomic indicators measured at the population level in the same cities. METHODS: We searched the literature in the medical databases and in the annals of scientific meeting, retrieving population-based surveys of asthma that were conducted in Brazil using the methodology defined by the International Study of Asthma and Allergies in Childhood. We performed separate analyses for the age groups 6-7 years and 13-14 years. We examined the association between asthma prevalence rates and eleven health and socio-economic indicators by visual inspection and using linear regression models weighed by the inverse of the variance of each survey. RESULTS: Six health and socioeconomic variables showed a clear pattern of association with asthma. The prevalence of asthma increased with poorer sanitation and with higher infant mortality at birth and at survey year, GINI index and external mortality. In contrast, asthma prevalence decreased with higher illiteracy rates. CONCLUSION: The prevalence of asthma in urban areas of Brazil, a middle income country, appears to be higher in cities with more marked poverty or inequality.
    • Estimating transmission intensity for a measles epidemic in Niamey, Niger: lessons for intervention.

      Grais, RF; Ferrari, M J; Dubray, C; Bjørnstad, O N; Grenfell, B T; Djibo, A; Fermon, F; Guerin, P J; Epicentre, 8 rue Saint Sabin, 75011 Paris, France. rebecca.grais@epicentre.msf.org (Elsevier, 2006-09)
      The objective of this study is to estimate the effective reproductive ratio for the 2003-2004 measles epidemic in Niamey, Niger. Using the results of a retrospective and prospective study of reported cases within Niamey during the 2003-2004 epidemic, we estimate the basic reproductive ratio, effective reproductive ratio (RE) and minimal vaccination coverage necessary to avert future epidemics using a recent method allowing for estimation based on the epidemic case series. We provide these estimates for geographic areas within Niamey, thereby identifying neighbourhoods at high risk. The estimated citywide RE was 2.8, considerably lower than previous estimates, which may help explain the long duration of the epidemic. Transmission intensity varied during the course of the epidemic and within different neighbourhoods (RE range: 1.4-4.7). Our results indicate that vaccination coverage in currently susceptible children should be increased by at least 67% (vaccine efficacy 90%) to produce a citywide vaccine coverage of 90%. This research highlights the importance of local differences in vaccination coverage on the potential impact of epidemic control measures. The spatial-temporal spread of the epidemic from district to district in Niamey over 30 weeks suggests that targeted interventions within the city could have an impact.
    • Human African trypanosomiasis amongst urban residents in Kinshasa: a case-control study.

      Robays, J; Ebeja, A; Lutumba, P; Miaka mia Bilenge, C; Kande Betu Ku Mesu, V; De Deken, R; Makabuza, J; Deguerry, M; Van der Stuyft, P; Boelaert, M; et al. (2004-08)
      BACKGROUND: Increasing numbers of human African trypanosomiasis (HAT) cases have been reported in urban residents of Kinshasa, Democratic Republic Congo since 1996. We set up a case-control study to identify risk factors for the disease. METHODS: All residents of the urban part of Kinshasa with parasitologically confirmed HAT and presenting for treatment to the city's specialized HAT clinics between 1 August, 2002 and 28 February, 2003 were included as cases. We defined the urban part as the area with contiguous habitation and a population density >5000 inhabitants per square kilometre. A digital map of the area was drawn based on a satellite image. For each case, two serologically negative controls were selected, matched on age, sex and neighbourhood. Logistic regression models were fitted to control for confounding. RESULTS: The following risk factors were independently associated with HAT: travel, commerce and cultivating fields in Bandundu, and commerce and cultivating fields in the rural part of Kinshasa. No association with activities in the city itself was found. DISCUSSION: In 2002, the emergence of HAT in urban residents of Kinshasa appears mainly linked to disease transmission in Bandundu and rural Kinshasa. We recommend to intensify control of these foci, to target HAT screening in urban residents to people with contact with these foci, to increase awareness of HAT amongst health workers in the urban health structures and to strengthen disease surveillance.
    • Lost to follow up from tuberculosis treatment in an urban informal settlement (Kibera), Nairobi, Kenya: what are the rates and determinants?

      Kizito, K W; Dunkley, S; Kingori, M; Reid, T; Médecins Sans Frontières - Operational Centre Belgium, Kenya Mission, Kileleshwa, Nairobi, Kenya. kwalta@gmail.com (2011-01)
      Patients lost to follow up (LTFU) from treatment are a major concern for tuberculosis (TB) programmes. It is even more challenging in programmes in urban informal settlements (slums) with large, highly mobile, impoverished populations. Kibera, on the outskirts of Nairobi, Kenya is such a community with an estimated population of 500,000 to 700,000. Médecins Sans Frontières (MSF), in collaboration with the Kenyan Ministry of Public Health and Sanitation (MPHS), operate three clinics providing integrated TB, HIV and primary health care. We undertook a retrospective study between July 2006 and December 2008 to determine the rate of LTFU from the TB programme in Kibera and to assess associated clinical and socio-demographic factors. Thanks to an innovative 'Defaulter Tracing Programme', patients who missed their appointments were routinely traced and encouraged to return for treatment. Where possible, reasons for missed appointments were recorded. LTFU occurred in 146 (13%) of the 1094 patients registered, with male gender, no salaried employment, lack of family support and positive TB smear at diagnosis found to be significant associations (P value ≤ 0.05). The most commonly cited reasons for LTFU were relocation from Kibera to 'up-country' rural homes and work commitments.
    • Prevalence and risk factors of Lassa seropositivity in inhabitants of the forest region of Guinea: a cross-sectional study.

      Kernéis, Solen; Koivogui, Lamine; Magassouba, N'Faly; Koulemou, Kekoura; Lewis, Rosamund; Aplogan, Aristide; Grais, RFebecca F; Guerin, Philippe J; Fichet-Calvet, Elisabeth; Epicentre, Paris, France. solen.kerneis@cch.aphp.com (2009-11)
      BACKGROUND: Lassa fever is a viral hemorrhagic fever endemic in West Africa. The reservoir host of the virus is a multimammate rat, Mastomys natalensis. Prevalence estimates of Lassa virus antibodies in humans vary greatly between studies, and the main modes of transmission of the virus from rodents to humans remain unclear. We aimed to (i) estimate the prevalence of Lassa virus-specific IgG antibodies (LV IgG) in the human population of a rural area of Guinea, and (ii) identify risk factors for positive LV IgG. METHODS AND FINDINGS: A population-based cross-sectional study design was used. In April 2000, all individuals one year of age and older living in three prefectures located in the tropical secondary forest area of Guinea (Gueckedou, Lola and Yomou) were sampled using two-stage cluster sampling. For each individual identified by the sampling procedure and who agreed to participate, a standardized questionnaire was completed to collect data on personal exposure to potential risk factors for Lassa fever (mainly contact with rodents), and a blood sample was tested for LV IgG. A multiple logistic regression model was used to determine risk factors for positive LV IgG. A total of 1424 subjects were interviewed and 977 sera were tested. Prevalence of positive LV Ig was of 12.9% [10.8%-15.0%] and 10.0% [8.1%-11.9%] in rural and urban areas, respectively. Two risk factors of positive LV IgG were identified: to have, in the past twelve months, undergone an injection (odds ratio [OR] = 1.8 [1.1-3.1]), or lived with someone displaying a haemorrhage (OR = 1.7 [1.1-2.9]). No factors related to contacts with rats and/or mice remained statistically significant in the multivariate analysis. CONCLUSIONS: Our study underlines the potential importance of person-to-person transmission of Lassa fever, via close contact in the same household or nosocomial exposure.
    • Sleeping sickness in the region of the town of Kinshasa: a retrospective analysis during the surveillance period 1996-2000.

      Ebeja, A; Lutumba, P; Molisho, D; Kegels, G; Miaka mia Bilenge, C; Boelaert, M; Médecins sans Frontières, Kinshasa, République Démocratique du Congo. kadima_ebeja@hotmail.com (Wiley-Blackwell, 2003-10)
      In the Democratic Republic of Congo, the re-emergence of sleeping sickness is no longer limited to rural areas. Over the course of the past decade, more and more cases have been reported from urban centres such as Kinshasa, Mbuji-mayi, Matadi and Boma. This paper presents a retrospective analysis on the region of Kinshasa over the period 1996-2000, using epidemiological surveillance, individual case files and available entomological data. There are 22 health districts in total; they were classified as urban when the population exceeded 5000 per square kilometre. The Human African Trypanosomiasis (HAT) control programme reported 2451 parasitologically confirmed new cases between 1996 and 2000, in the entire region of Kinshasa. Affected people (66%) were aged 15-49 years. Cases occurred in every health district, and 956 (39%) occurred in urban residents. Glossina captures in 1999 established the presence of Trypanosoma spp. Local HAT transmission is plausible but not proven. The high number of urban cases necessitates development of control strategies adapted to cities.