P. Van der Stuyft

The unreliability of the Kato-Katz technique limits its usefulness for evaluating S. mansoni infections

The Kato‐Katz technique, a (semi) quantitative stool examination technique, is generally recommended for diagnosis and evaluation of Schistosoma mansoni infection by schistosome experts. However, egg counts are subject to important variability. In order to quantify the reproducibility of egg counts using the Kato‐Katz technique, field data of 1255 observations on 299 subjects infected with Schistosoma mansoni were analysed. Agreement between repeated observations was assessed both categorically (kappa statistic) and continuously (analysis of variance). The day‐to‐day variation of egg counts was much greater than the variation due to different observers or different slides. The quantitative reproducibility was low: the weighted kappa statistic was 0.39 between specimens of different days, 0.62 between slides of the same specimen and 0.81 between observers of the same slide. Therefore the classification of individual patients into groups based on egg counts, used as a measure of morbidity, must be interpreted with great care, especially in longitudinal studies. Usefulness of the Kato‐Katz technique appears limited. Its reproducibility is low. It cannot be recommended as a routine test in a primary health care setting or in a hospital laboratory because safety and detection of other parasites are better assured by other techniques. It can be used in epidemiological studies and evaluation of schistosomiasis control programmes, but here too, other techniques might be preferred.

Incidence of malaria and efficacy of oral quinine in patients recently infected with human immunodeficiency virus in Kinshasa, Zaire

There is concern that the impaired cell mediated immunity caused by the human immunodeficiency virus may increase the risk of severity of Plasmodium falciparum infection and could lead eventually to a decreased response to standard antimalarial treatment. In 1986, at Mama Yemo Hospital, Kinshasa, Zaire, the incidence of malaria was determined in a cohort of 59 patients who had recently acquired HIV-I infection through blood transfusion and in a cohort of 83 HIV-I seronegative controls who were recipients of HIV-I seronegative blood. All cohort patients were asked to visit the study physician whenever they developed fever. On each of these occasions thick film was examined for the presence of malarial parasites. HIV-I seropositive patients presented more often with episodes of fever per person month observation than HIV-I seronegative patients (P = 0.003). The total number of positive thick films per person months observation was significantly higher among HIV-I seropositive patients than among the HIV-I seronegative ones, but percentages of positive thick films per episode of fever were the same in both groups (46%). During a 5 month period, cohort patients presenting with a moderate attack of malaria were treated with oral quinine 20 mg/kg daily in two doses for 5 days. Twenty-three (92%) of 25 HIV-I seropositive patients and 28 (82%) of 34 HIV-I seronegative patients had a negative film 7 days after starting treatment. This study suggests that there seems to be no direct interaction of major clinical importance between HIV infection and malaria.

Evaluation of a urinary antigen‐based latex agglutination test in the diagnosis of kala‐azar in eastern Nepal

Background  We evaluated the diagnostic accuracy as well as the reproducibility of the urine latex agglutination test ‘KAtex’ in the diagnosis of kala‐azar in patients recruited at a tertiary care centre in Dharan, Nepal, between November 2000 and January 2002.

Intersectoral coordination in Aedes aegypti control. A pilot project in Havana City, Cuba

Background  The 55th World Health Assembly declared dengue prevention and control a priority and urged Member States to develop sustainable intersectoral strategies to this end. To provide evidence for the reorientation of the dengue prevention policy in Cuba, we launched an intervention study to document the effectiveness of a local‐level intersectoral approach.

Editorial: Delays to tuberculosis treatment: shall we continue to blame the victim?

Delayed diagnosis and treatment of pulmonary tuberculosis (PTB) entail increased transmission, since patients are contagious until effective chemotherapy is started (Rieder 1999). Health education on ‘TB signs and symptoms’ is often advocated in order to reduce delays and increase case detection, under the hypothesis that ‘lack of knowledge about TB’ determines care seeking among patients. The only published literature review on the subject of delays to TB treatment is based on qualitative studies (Thomas 2002) and concludes that ‘the main reasons for delayed presentation of TB are a lack of understanding about TB, the stigma associated with the disease, the inaccessibility of treatment, and a preference for private practitioners’ (in that order). Quantitative studies to measure delays to TB treatment rely on interviews of diagnosed patients. Of 13 such studies, published between 1995 and 2004 in the International Journal of Tuberculosis and Lung Diseases, a leading journal in the field of tuberculosis, 10 include ‘improving awareness of TB in the community’ amongst their recommendations for reducing long delays to TB treatment. Does patients’ ‘lack of knowledge of TB’ indeed substantially contribute to long delays to TB treatment, compared to other factors, and should ‘awareness of the disease be increased in the community’, for more effective and successful tuberculosis control? The evidence for this is actually rather weak. The TB control strategy currently promoted by WHO in high prevalence countries is to identify tuberculosis cases among people with symptoms (most importantly, prolonged cough) attending general health services (WHO 2003). The unchallenged assumption behind this approach is that symptoms of TB are so severe that cases will seek treatment soon after they develop (Newell 2002). From a TB control point of view, the target for patient delay – the time from the onset of symptoms to the first contact with a qualified health provider – is 2 or 3 weeks. Not only patient factors, but also health services factors, such as accessibility or quality of services, can contribute to patient delay. As for provider delay – the time elapsed from a first contact to the start of treatment – it could in theory be only a few days, if a sputum test is requested and processed in due time for all eligible patients. In an ideal world, total delay to TB treatment (the sum of patient and provider delay) would hence be no more than 3–4 weeks for the majority of smear-positive TB patients. Reported delays to TB treatment vary widely across studies, and are mainly meaningful in their own context. Differences in study methods, not least the definition of health care provider, also preclude comparisons. In fact, few of the studies with recommendations to ‘educate the population’ in order to reduce delays do actually investigate ‘knowledge of TB’ among TB patients. Even fewer measure ‘knowledge of TB’ in relation to delays to diagnosis. Those which do are hardly convincing. In India (Rajeswari et al. 2002), ‘lack of awareness about TB’ was cited by 40% of patients with long patient delays as a reason for delayed care seeking, but this ‘lack of awareness about TB’ was not investigated among patients reporting short patient delays. In Nigeria (Enwuru et al. 2002), ‘lack of knowledge about TB’ was associated with longer patient delays, but no other possible reason for patient delay was investigated and the association was not adjusted for level of education or other confounding factors. Also, many studies emphasize patient factors over provider factors when analysing reasons for delays or commenting on their findings – even when the data suggest otherwise. For instance, median provider (doctor) delay exceeded its target much more than median patient delay in studies from Malaysia (Liam & Tang 1997), The Gambia (Lienhardt et al. 2001), or India (Rajeswari et al. 2002), but in these studies the recommendations to ‘educate communities’ come first, before recommendations to ‘educate providers’. The exhaustive list of similar examples would be long (and boring). Cultural patient factors like stigma or consulting a traditional healer may indeed play a role in delayed careseeking, but their importance compared with health services factors should be properly evaluated. In Botswana delays were longer among patients who had consulted a traditional healer, but in this study median provider (doctor) delay in itself was 5 weeks (Steen & Mazonde 1998). This is the priority problem: total delay to TB Tropical Medicine and International Health doi:10.1111/j.1365-3156.2005.01485.x

Drug policy for visceral leishmaniasis: a cost‐effectiveness analysis

Objective  To facilitate the choice of the best visceral leishmaniasis (VL) treatment strategy for first‐line health services in (VL)‐endemic areas, we compared in a formal decision analysis the cost and the cost‐effectiveness of the different available options.

Community participation in Aedes aegypti control: a sociological perspective on five years of research in the health area '26 de Julio', Havana, Cuba

Objective:  Effective dengue prevention and Aedes aegypti control is a priority for the Cuban health authorities. To enhance effectiveness, strategies oriented towards a more active involvement of communities in control activities are being tested. This paper presents a sociological perspective on a pilot project conducted in the health area ‘‘26 de Julio’’ (La Havana) in 1999–2004.

Multi-centre evaluation of repeatability and reproducibility of the direct agglutination test for visceral leishmaniasis

Summary objective  To evaluate the repeatability and reproducibility of the serological direct agglutination test (DAT) for visceral leishmaniasis (VL) with aqueous antigen in a multi‐centre study in VL‐endemic areas in Sudan, Kenya and Nepal.

Drug toxicity and cost as barriers to community participation in HAT control in the Democratic Republic of Congo

Introduction  Active case‐finding programmes by mobile teams are the cornerstone of West African Human African Trypanosomiasis (HAT) control. Low attendance rates of screening and low uptake of treatment after diagnosis are major problems. The objectives of this survey were to explore community perception of HAT, to assess acceptability of control activities and to identify barriers amenable to intervention.

Breteau Index threshold levels indicating risk for dengue transmission in areas with low Aedes infestation.

We used Breteau Indices to – retrospectively – predict dengue transmission. The presence of one house block (on average about 50 houses) with a Breteau Index ≥4 in a neighbourhood (a block plus the surrounding blocks in a radius of 100 m) predicted transmission at the latter level with 81.8% sensitivity and 73.3% specificity during the first month of the Havana 2001 dengue outbreak. This result corroborates the external validity of this threshold, at least in situations with low infestations levels.