Showing papers in "Transactions of The Royal Society of Tropical Medicine and Hygiene in 2007"

What do community-based dengue control programmes achieve? A systematic review of published evaluations

Abstract: Summary Owing to increased epidemic activity and difficulties in controlling the insect vector, dengue has become a major public health problem in many parts of the tropics. The objective of this review is to analyse evidence regarding the achievements of community-based dengue control programmes. Medline, EMBASE, WHOLIS and the Cochrane Database of Systematic Reviews were searched (all to March 2005) to identify potentially relevant articles using keywords such as ‘Aedes’, ‘dengue’, ‘breeding habits’, ‘housing’ and ‘community intervention’. According to the evaluation criteria recommended by the Cochrane Effective Practice and Organisation of Care Review Group, only studies that met the inclusion criteria of randomised controlled trials (RCT), controlled clinical trials (CCT), controlled before and after trials (CBA) or interrupted time series (ITS) were included. Eleven of 1091 studies met the inclusion criteria. Of these, two were RCTs, six were CBAs and three were ITS. The selected studies varied widely with respect to target groups, intervention procedures and outcome measurements. Six studies combined community participation programmes with dengue control tools. Methodological weaknesses were found in all studies: only two papers reported confidence intervals (95% CI); five studies reported P-values; two studies recognised the importance of water container productivity as a measure for vector density; in no study was cluster randomisation attempted; and in no study were costs and sustainability assessed. Evidence that community-based dengue control programmes alone and in combination with other control activities can enhance the effectiveness of dengue control programmes is weak.

Exploring the contributions of bed nets, cattle, insecticides and excitorepellency to malaria control: a deterministic model of mosquito host-seeking behaviour and mortality

Abstract: Domestic and personal protection measures against malaria exposure either divert host-seeking vectors to other hosts or kill those attempting to feed. Here, we explicitly model mosquito host-seeking processes in the context of local host availability and elucidate the impacts and mechanisms of pyrethroid-treated bed nets in Africa. It has been suggested that excitorepellent insecticides could increase exposure of unprotected humans by concentrating mosquito biting activity on this vulnerable group. This worst-case scenario is confirmed as a possibility where vector populations lack alternative hosts, but an approximate 'break-even' scenario, with users experiencing little overall change in exposure, is more likely because of increased mosquito mortality while foraging for resources. Insecticidal nets are predicted to have epidemiologically significant impacts on transmission experienced by users and non-users at levels of coverage that can be achieved by sustainable net distribution systems, regardless of excitorepellency or the ecological setting. The results are consistent with the outcome of several randomised controlled trials, predicting enormous reductions in transmission at individual and community levels. As financial support, technology and distribution systems for insecticide-treated nets improve, massive reductions in malaria transmission could be realised.

Therapeutic response of multidrug-resistant Plasmodium falciparum and P. vivax to chloroquine and sulfadoxine–pyrimethamine in southern Papua, Indonesia

Abstract: To determine the level of antimalarial drug resistance in southern Papua, Indonesia, we assessed the therapeutic efficacy of chloroquine plus sulfadoxine–pyrimethamine (CQ+SP) for Plasmodium falciparum infections as well as CQ monotherapy for P. vivax infections. Patients with P. falciparum failing therapy were re-treated with unsupervised quinine ± doxycycline therapy and those with P. vivax with either unsupervised quinine ± doxycycline or amodiaquine. In total, 143 patients were enrolled in the study (103 treated with CQ+SP and 40 with CQ). Early treatment failures occurred in four patients (4%) with P. falciparum and six patients (15%) with P. vivax. The failure rate by Day 28 for P. vivax was 65% (95% CI 49–81). After PCR correction for re-infections, the Day 42 recrudescence rate for P. falciparum infections was 48% (95% CI 31–65). Re-treatment with unsupervised quinine ± doxycycline resulted in further recurrence of malaria in 48% (95% CI 31–65) of P. falciparum infections and 70% (95% CI 37–100) of P. vivax infections. Eleven patients with recurrent P. vivax were re-treated with amodiaquine; there were no early or late treatment failures. In southern Papua, a high prevalence of drug resistance of P. falciparum and P. vivax exists both to first- and second-line therapies. Preliminary data indicate that amodiaquine retains superior efficacy compared with CQ for CQ-resistant P. vivax.

The heat stability of Plasmodium lactate dehydrogenase-based and histidine-rich protein 2-based malaria rapid diagnostic tests.

Abstract: Malaria rapid diagnostic tests (RDTs) have performed well in a variety of studies, but recent reports have described sensitivity for Plasmodium falciparum as significantly lower than that required for operational deployment. Exposure to high temperature has been suggested as an explanation. This study assessed the temperature stability of two different Plasmodium lactate dehydrogenase (pLDH)- and three histidine-rich protein 2 (HRP2)-detecting RDTs. One HRP2 test proved insufficiently sensitive for assessment. After incubation at 35, 45 and 60 degrees C, two RDTs detecting pLDH showed a substantial fall in percentage test line positivity over time, which was not seen with the remaining two HRP-2-based RDTs. For the particular products studied, variability was high, with the pLDH-based RDTs being less sensitive than HRP2-based RDTs against the sample of P. falciparum used and more susceptible to heat-induced damage, but the reasons for this are unclear. The performance of malaria RDTs can be adversely affected at the temperatures to which they will be exposed when transported to, and used in, the rural tropics.

Community support is associated with better antiretroviral treatment outcomes in a resource-limited rural district in Malawi.

Abstract: A study was carried in a rural district in Malawi among HIV-positive individuals placed on antiretroviral treatment (ART) in order to verify if community support influences ART outcomes. Standardized ART outcomes in areas of the district with and without community support were compared. Between April 2003 (when ART was started) and December 2004 a total of 1634 individuals had been placed on ART. Eight hundred and ninety-five (55%) individuals were offered community support, while 739 received no such support. For all patients placed on ART with and without community support, those who were alive and continuing ART were 96 and 76%, respectively (P<0.001); death was 3.5 and 15.5% (P<0.001); loss to follow-up was 0.1 and 5.2% (P<0.001); and stopped ART was 0.8 and 3.3% (P<0.001). The relative risks (with 95% CI) for alive and on ART [1.26 (1.21-1.32)], death [0.22 (0.15-0.33)], loss to follow-up [0.02 (0-0.12)] and stopped ART [0.23 (0.08-0.54)] were all significantly better in those offered community support (P<0.001). Community support is associated with a considerably lower death rate and better overall ART outcomes. The community might be an unrecognized and largely 'unexploited resource' that could play an important contributory role in countries desperately trying to scale up ART with limited resources.

Spatial epidemiology of human schistosomiasis in Africa: risk models, transmission dynamics and control.

Abstract: This paper reviews recent studies on the spatial epidemiology of human schistosomiasis in Africa. The integrated use of geographical information systems, remote sensing and geostatistics has provided new insights into the ecology and epidemiology of schistosomiasis at a variety of spatial scales. Because large-scale patterns of transmission are influenced by climatic conditions, an increasing number of studies have used remotely sensed environmental data to predict spatial distributions, most recently using Bayesian methods of inference. Such data-driven approaches allow for a more rational implementation of intervention strategies across the continent. It is suggested that improved incorporation of transmission dynamics into spatial models and assessment of uncertainties inherent in data and modelling approaches represent important future research directions.

Podoconiosis: non-infectious geochemical elephantiasis.

Abstract: This article reviews peer-reviewed publications and book chapters on the history, epidemiology, genetics, ecology, pathogenesis, pathology and management of podoconiosis (endemic non-filarial elephantiasis). Podoconiosis is a non-infectious geochemical elephantiasis caused by exposure of bare feet to irritant alkalic clay soils. It is found in at least 10 countries in tropical Africa, Central America and northwest India, where such soils coexist with high altitude, high seasonal rainfall and low income. Podoconiosis develops in men and women working barefoot on irritant soils, with signs becoming apparent in most patients by the third decade of life. Colloid-sized silicate particles appear to enter through the skin, are taken up into macrophages in the lower limb lymphatics and cause endolymphangitis and obliteration of the lymphatic lumen. Genetic studies provide evidence for high heritability of susceptibility to podoconiosis. The economic burden is significant in affected areas dependent on subsistence farming. Podoconiosis is unique in being an entirely preventable non-communicable disease. Primary prevention entails promoting use of footwear in areas of irritant soil; early stages are reversible given good foot hygiene, but late stages result in considerable economic and social difficulties, and require extended periods of elevation and occasionally nodulectomy.

Water handling, sanitation and defecation practices in rural southern India: a knowledge, attitudes and practices study

Abstract: Diarrhoea and water-borne diseases are leading causes of mortality in developing countries. To understand the socio-cultural factors impacting on water safety, we documented knowledge, attitudes and practices of water handling and usage, sanitation and defecation in rural Tamilnadu, India, using questionnaires and focus group discussions, in a village divided into an upper caste Main village and a lower caste Harijan colony. Our survey showed that all households stored drinking water in wide-mouthed containers. The quantity of water supplied was less in the Harijan colony, than in the Main village (P<0.001). Residents did not associate unsafe water with diarrhoea, attributing it to 'heat', spicy food, ingesting hair, mud or mosquitoes. Among 97 households interviewed, 30 (30.9%) had toilets but only 25 (83.3%) used them. Seventy-two (74.2%) of respondents defecated in fields, and there was no stigma associated with this traditional practice. Hand washing with soap after defecation and before meals was common only in children under 15 years (86.4%). After adjusting for other factors, perception of quantity of water received (P<0.001), stated causation of diarrhoea (P=0.02) and low socio-economic status (P<0.001) were significantly different between the Main village and the Harijan colony. Traditional practices may pose a significant challenge to programmes aimed at toilet usage and better sanitation.

Heavy cryptosporidial infections in children in northeast Brazil: comparison of Cryptosporidium hominis and Cryptosporidium parvum

Abstract: Cryptosporidium is an important cause of infectious diarrhoea worldwide, but little is known about the course of illness when infected with different species. Over a period of 5 years, Cryptosporidium was identified in the stools of 58 of 157 children prospectively followed from birth in an urban slum (favela) in northeast Brazil. Forty isolates were available for quantification and 42 for speciation (24 Cryptosporidium hominis and 18 C. parvum). Children with C. hominis shed significantly more oocysts/ml of stool (3.5 x 10(6) vs. 1.7 x 10(6)perml; P=0.001), and oocyst counts were higher among symptomatic children (P=0.002). Heavier C. parvum shedding was significantly associated with symptoms (P=0.004), and symptomatic C. parvum-infected children were significantly more likely than asymptomatic children to be lactoferrin-positive (P=0.004). Height-for-age (HAZ) Z-scores showed significant declines within 3 months of infection for children infected with either C. hominis (P=0.028) or C. parvum (P=0.001). However, in the 3-6 month period following infection, only C. hominis-infected children continued to demonstrate declining HAZ score and asymptomatic children showed even greater decline (P=0.01). Cryptosporidium hominis is more common than C. parvum in favela children and is associated with heavier infections and greater growth shortfalls, even in the absence of symptoms.

High prevalence of lipoatrophy among patients on stavudine-containing first-line antiretroviral therapy regimens in Rwanda.

Abstract: Summary This study was conducted among individuals placed on WHO-recommended first-line antiretroviral therapy (ART) at two urban health centres in Kigali, Rwanda, in order to determine (a) the overall prevalence of lipodystrophy and (b) the risk factors for lipoatropy. Consecutive individuals on ART for >1 year were systematically subjected to a standardised case definition-based questionnaire and clinical assessment. Of a total of 409 individuals, 370 (90%) were on an ART regimen containing stavudine (d4T), whilst the rest were receiving a zidovudine (AZT)-containing regimen. Lipodystrophy was apparent in 140 individuals (34%), of whom 40 (9.8%) had isolated lipoatrophy, 20 (4.9%) had isolated lipohypertrophy and 80 (19.6%) had mixed patterns. Fifty-six percent of patients reported the effects as disturbing. The prevalence of lipoatrophy was more than three times higher when taking d4T compared with AZT-containing regimens (31.4% vs. 10.3%). Being female, d4T-based ART, baseline body mass index ≥25 kg/m 2 or baseline CD4 count ≥150 cells/μl and increasing duration of ART were all significantly associated with lipoatrophy. Lipoatrophy appears to be an important long-term complication of WHO-recommended first-line ART regimens. These data highlight the urgent need for access to more affordable and less toxic ART regimens in resource-limited settings.

Epidemiology of Opisthorchis viverrini in a rural district of southern Lao PDR

Abstract: In Lao PDR, detailed investigations on Opisthorchis viverrini are scarce. The objective was to document epidemiological features of O. viverrini infections in a highly endemic district. A random sample was selected (13 villages, 15 households/village, all household members aged >6 months). Clinical examinations, short interviews and stool examinations (Kato-Katz technique) were performed. Fish samples were dissected for the presence of metacercaria. In total, 814 persons were enrolled (median age 16 years, 51.5% women). The prevalence was 58.5%. Infection rates increased with age (from 20.0 to 85.5%; P<0.001). Intensity of infection and the habit of consuming insufficiently cooked fish also increased with age. Of the study participants, 75.2% reported cooking fish insufficiently. Of the 23 different species of cyprinoid fish consumed in the study villages, 20 species were infected. At the village level, the prevalence of raw fish consumption was strongly associated with the infection status of O. viverrini (r=0.76, P=0.003). At individual level, age, the consumption of insufficiently cooked fish, and the absence of sanitation were strongly associated. The disease associated with O. viverrini infection needs to be assessed in order to develop and conduct adequate interventions.

Chronic renal failure in North Central Province of Sri Lanka: an environmentally induced disease.

Abstract: This study was conducted to determine the aetiology of chronic renal failure (CRF) in the North Central Province of Sri Lanka. Patients (n = 183) with CRF of unknown aetiology were compared with controls (n = 200) who had no evidence of chronic renal dysfunction. Exposure to possible risk factors were determined by an interviewer-administered questionnaire. Being a farmer (P < 0.001), using pesticides (P < 0.001), drinking well water (P < 0.001), a family history of renal dysfunction (P = 0.001), use of ayurvedic treatment (P < 0.001) and a history of snake bite (P < 0.001) were risk factors for CRF of unknown aetiology. Using logistic regression analysis, a family history of chronic renal disease, taking ayurvedic treatment and history of snake bite were found to be significant predictors for CRF of unknown aetiology. There is evidence to support an environmental aetiology to CRF in Sri Lanka.

Time delays between patient and laboratory selectively affect accuracy of helminth diagnosis

Abstract: Studies of intestinal helminth infections are influenced by the constraints of sample collection, as identification of helminth ova in stools is affected by the time since evacuation from the host. Different methods may be required to optimise diagnostic sensitivity under different study conditions. In the context of studies in rural Malawi, we collected stool samples with different time delays from production by subjects to sample collection by field staff, to examination in the laboratory. Stools were processed by Kato-Katz (KK) or formol-ether concentration (FEC) methods. Hookworm and Schistosoma mansoni were the most common helminths identified. The prevalence of hookworm was higher with KK (270/988, 27%) than with FEC (191/988, 19%). Comparison was made between the results from the two methods according to the timing of the processing steps. Delays in processing did not affect retrieval of S. mansoni. A decrease in sensitivity of almost 50% for detection of hookworm was observed with either method when preservation/refrigeration was delayed by more than 3h. A delay of 1 day from refrigeration or preservation to laboratory processing also reduced the sensitivity for hookworm by 50% for both methods. Care must be taken in studies of multiple helminth infections owing to the selective reduction of hookworm ova during transport. This is particularly critical when samples are not preserved, even over short periods of time, and even with formalin preservation.

The hygiene hypothesis and the increasing prevalence of chronic inflammatory disorders

Abstract: The 'Hygiene' or 'Old Friends' hypothesis suggests that increases in chronic inflammatory disorders (allergies, inflammatory bowel disease and autoimmunity) in developed countries are partly attributable to diminishing exposure to organisms that were part of mammalian evolutionary history. Crucial organisms, including helminths and saprophytic mycobacteria, are recognised by the innate immune system as harmless or, in the case of helminths, as organisms that once established must be tolerated. This recognition then triggers development of regulatory dendritic cells that drive regulatory T-cell responses to the 'Old Friends' themselves and to simultaneously processed 'forbidden' target antigens of the chronic inflammatory disorders.

Plasmodium vivax infection among Duffy antigen-negative individuals from the Brazilian Amazon region: an exception?

Abstract: We present evidence for Plasmodium vivax infection among Duffy blood group-negative inhabitants of Brazil. The P. vivax identification was determined by both genotypic and non-genotypic screening tests. The Duffy blood group was genotyped by PCR/RFLP and phenotyped using a microtyping kit. We detected two homozygous FY*B-33 carriers infected by P. vivax, whose circumsporozoite protein genotypes were VK210 and/or P. vivax-like. Additional efforts are necessary in order to clarify the evidence that P. vivax is being transmitted among Duffy blood group-negative patients from the Brazilian Amazon region.

RT-PCR assay for detection of Lassa virus and related Old World arenaviruses targeting the L gene.

Abstract: This study describes an RT-PCR assay targeting the L RNA segment of arenaviruses. Conserved regions were identified in the polymerase domain of the L gene on the basis of published sequences for Lassa virus, lymphocytic choriomeningitis virus (LCMV), Pichinde virus and Tacaribe virus, as well as 15 novel sequences for Lassa virus, LCMV, Ippy virus, Mobala virus and Mopeia virus determined in this study. Using these regions as target sites, a PCR assay for detection of all known Old World arenaviruses was developed and optimized. The concentration that yields 95% positive results in a set of replicate tests (95% detection limit) was determined to be 4290 copies of Lassa virus L RNA per ml of serum, corresponding to 30 copies per reaction. The ability of the assay to detect various Old World arenaviruses was demonstrated with in vitro transcribed RNA, material from infected cell cultures and samples from patients with Lassa fever and monkeys with LCMV-associated callitrichid hepatitis. The L gene PCR assay may be applicable: (i) as a complementary diagnostic test for Lassa virus and LCMV; (ii) to identify unknown Old World arenaviruses suspected as aetiological agents of disease; and (iii) for screening of potential reservoir hosts for unknown Old World arenaviruses.

Associations between mild-to-moderate anaemia in pregnancy and helminth, malaria and HIV infection in Entebbe, Uganda

Abstract: It is suggested that helminths, particularly hookworm and schistosomiasis, may be important causes of anaemia in pregnancy. We assessed the associations between mild-to-moderate anaemia (haemoglobin >8.0 g/dl and <11.2 g/dl) and helminths, malaria and HIV among 2507 otherwise healthy pregnant women at enrolment to a trial of deworming in pregnancy in Entebbe, Uganda. The prevalence of anaemia was 39.7%. The prevalence of hookworm was 44.5%, Mansonella perstans 21.3%, Schistosoma mansoni 18.3%, Strongyloides 12.3%, Trichuris 9.1%, Ascaris 2.3%, asymptomatic Plasmodium falciparum parasitaemia 10.9% and HIV 11.9%. Anaemia showed little association with the presence of any helminth, but showed a strong association with malaria (adjusted odds ratio (AOR) 3.22, 95% CI 2.43–4.26) and HIV (AOR 2.46, 95% CI 1.90–3.19). There was a weak association between anaemia and increasing hookworm infection intensity. Thus, although highly prevalent, helminths showed little association with mild-to-moderate anaemia in this population, but HIV and malaria both showed a strong association. This result may relate to relatively good nutrition and low helminth infection intensity. These findings are pertinent to estimating the disease burden of helminths and other infections in pregnancy. [Clinical Trial No. ISRCTN32849447]

Towards active community participation in dengue vector control: results from action research in Santiago de Cuba, Cuba

Abstract: Community participation is advocated as essential for attaining effective dengue prevention, but knowledge of how to foster this is limited. In Santiago de Cuba, multiple small task forces were created at the neighbourhood level that included all stakeholders in the control of Aedes aegypti. The task forces assessed the perceived needs and elaborated action plans to promote specific behavioural change and to reduce environmental risks through social communication strategies and intersectoral local government activities. We monitored five dimensions of the participation process and assessed behavioural and environmental results and entomological outcomes. Participation was weak to good. At the household level, uncovered water storage containers decreased from 49.3% to 2.6% between 2000 and 2002, and removing larvicide from them dropped from 45.5% to 1%. There was a reduction of 75% in the absolute number of positive containers and a significant decrease from 1.23% to 0.35% in the house index. Local task forces, in which the interests of householders as well as vector control workers are directly represented, can lead to effective government-community partnerships that resolve problems of mutual concern.

Dengue outbreak in Karachi, Pakistan, 2006: experience at a tertiary care center.

Abstract: This is the first report of the largest epidemic of dengue hemorrhagic fever (DHF) virus infection (2006) with IgM-confirmed cases from Karachi, Pakistan. Medical records of 172 IgM-positive patients were reviewed retrospectively for demographic, clinical and laboratory data. Patients were categorized into dengue fever (DF) and DHF according to the WHO severity grading scale. The mean+/-SD age of the patients was 25.9+/-12.8 years, 55.8% were males and the hemoconcentration was recorded in a small number of patients [10 (7.0%)]. Male gender [odds ratio (OR)=14.7, P=0.003), positive history of vomiting (OR=4.3, P=0.047), thrombocytopenia at presentation (OR=225.2, P<0.001) and monocytosis (OR=5.8, P=0.030) were independently associated with DHF, but not with DF. Five cases (2.9%) had a fatal outcome, with a male-to-female ratio of 1:4. Three were from a pediatric group (<15 years). Pulmonary hemorrhages, disseminated intravascular coagulation and cerebral edema preceded death in these patients. The results have highlighted significant findings, such as adult susceptibility to DHF, pronounced abdominal symptoms and lack of hemoconcentration at time of presentation in the study population. These findings may play an important role in the case definitions of future studies from this part of the world.

First authenticated cases of life-threatening envenoming by the hump-nosed pit viper (Hypnale hypnale) in India.

Abstract: In Kerala, south-western India, five patients developed systemic envenoming after bites by hump-nosed pit vipers (Hypnale hypnale), proved by identification of the snakes responsible. Two of the dead snakes had been misidentified as saw-scaled vipers (Echis carinatus), while three had remained unidentified. Symptoms of local envenoming were pain, swelling, haemorrhagic blistering, bruising and regional lymphadenopathy. Systemic symptoms included headache, nausea, vomiting and abdominal and chest pain. There was evidence of haemostatic dysfunction (coagulopathy, fibrinolysis, thrombocytopenia or spontaneous systemic haemorrhage) in all cases and of microangiopathic haemolysis in two. Two patients were haemodialysed for acute renal failure, one of whom developed pulmonary oedema requiring mechanical ventilation. In India, H. hypnale has not previously been regarded as a cause of frequent or potentially dangerous envenoming. Its medical importance has been overlooked throughout its geographical range, probably because of confusion with other small species. No specific antivenom exists, yet most patients are treated with non-specific antivenoms, risking reactions without hope of benefit. An effective antivenom is urgently needed in south India and in Sri Lanka, where this species is also a common cause of bites.

Efficacy and safety of dihydroartemisinin-piperaquine.

Abstract: Dihydroartemisinin-piperaquine, a fixed-dose combination antimalarial, is an inexpensive, safe and highly effective treatment for uncomplicated falciparum or vivax malaria. Efficacy assessed over 28-63 days has consistently exceeded 95% in the treatment of multidrug-resistant falciparum malaria. More than 2600 patients have been treated with this combination in prospective studies, mainly in Southeast Asia. Tolerability was uniformly good, and no serious adverse effects have been identified. The dosing regimen has been simplified from four doses to once daily over 3 days. More information on efficacy in Africa, and more pharmacokinetic and efficacy data in children are needed.

Argemone mexicana decoction for the treatment of uncomplicated falciparum malaria.

Abstract: A prospective, dose-escalating, quasi-experimental clinical trial was conducted with a traditional healer using a decoction of Argemone mexicana for the treatment of malaria in Mali. The remedy was prescribed in three regimens: once daily for 3 days (Group A; n=23); twice daily for 7 days (Group B; n=40); and four times daily for the first 4 days followed by twice daily for 3 days (Group C; n=17). Thus, 80 patients were included, of whom 80% were aged 2000/microl but no signs of severe malaria. The proportions of adequate clinical response (ACR) at Day 14 were 35%, 73% and 65% in Groups A, B and C, respectively (P=0.011). At Day 14, overall proportions of ACR were lower in children aged 5 years (81%) (P=0.027). Very few patients had complete parasite clearance, but at Day 14, 67% of patients with ACR had a parasitaemia<2000/microl. No patient needed referral for severe disease. Only minor side effects were observed. Further research should determine whether this local resource could represent a first-aid home treatment in remote areas.

Congenital Trypanosoma cruzi infection in a non-endemic area

Abstract: In May 2004, after launching a screening programme to detect Trypanosoma cruzi infection in the Latin American population, a case of congenital infection in a 2-year-old boy was discovered in Barcelona. Few cases of congenital transmission have been described in non-endemic areas and little is known about the epidemiological and clinical features of congenital Chagas disease in this context. The increase in Latin American immigrants in Europe and the USA requires greater epidemiological surveillance and appropriate diagnostic techniques for managing T. cruzi infections.

Minimising human error in malaria rapid diagnosis: clarity of written instructions and health worker performance.

Abstract: The usefulness of rapid diagnostic tests (RDT) in malaria case management depends on the accuracy of the diagnoses they provide. Despite their apparent simplicity, previous studies indicate that RDT accuracy is highly user-dependent. As malaria RDTs will frequently be used in remote areas with little supervision or support, minimising mistakes is crucial. This paper describes the development of new instructions (job aids) to improve health worker performance, based on observations of common errors made by remote health workers and villagers in preparing and interpreting RDTs, in the Philippines and Laos. Initial preparation using the instructions provided by the manufacturer was poor, but improved significantly with the job aids (e.g. correct use both of the dipstick and cassette increased in the Philippines by 17%). However, mistakes in preparation remained commonplace, especially for dipstick RDTs, as did mistakes in interpretation of results. A short orientation on correct use and interpretation further improved accuracy, from 70% to 80%. The results indicate that apparently simple diagnostic tests can be poorly performed and interpreted, but provision of clear, simple instructions can reduce these errors. Preparation of appropriate instructions and training as well as monitoring of user behaviour are an essential part of rapid test implementation.

Age-related changes in hookworm infection, anaemia and iron deficiency in an area of high Necator americanus hookworm transmission in south-eastern Brazil

Abstract: Surprisingly few detailed age-stratified data exist on the epidemiology of hookworm and iron status, especially in Latin America. We present data from a cross-sectional survey examining 1332 individuals aged 0-86 years from a community in south-east Brazil for hookworm, anaemia and iron deficiency. Sixty-eight percent of individuals were infected with the human hookworm Necator americanus. The force of infection (lambda=0.354) was similar to estimates from other areas of high hookworm transmission. Individuals from poorer households had significantly higher prevalence and intensity of infection than individuals from better-off households. The prevalence of anaemia, iron deficiency and iron-deficiency anaemia was 11.8%, 12.7% and 4.3%, respectively. Anaemia was most prevalent among young children and the elderly. Univariate analysis showed that haemoglobin and serum ferritin were both significantly negatively associated with hookworm intensity among both school-aged children and adults. Multivariate analysis showed that, after controlling for socio-economic status, iron indicators were significantly associated with heavy hookworm infection. Our results indicate that, even in areas where there is a low overall prevalence of anaemia, hookworm can still have an important impact on host iron status, especially in school-aged children and the elderly.

The cosmetic use of skin-lightening products during pregnancy in Dakar, Senegal: a common and potentially hazardous practice

Abstract: Many women of childbearing age from sub-Saharan Africa use topical skin lighteners, some of which present a risk of toxic systemic effects. The goals of this study were to evaluate, in this environment, the frequency of this practice during pregnancy, as well as eventual consequences on pregnancy. Ninety-nine women from 6 to 9 months pregnant were randomly selected among those attending a standard maternal centre in Dakar for a prenatal visit. Investigations consisted of questions about the use of skin lighteners, a standard clinical examination, follow-up until delivery and a morning blood sample for plasma cortisol levels. Sixty-eight of the 99 selected women used skin lighteners during their current pregnancy, the main active ingredients being hydroquinone and highly potent steroids (used by 64 and 28 women, respectively). No difference in the main outcomes of pregnancy were found between skin-lightener users and the others; however, women using highly potent steroids, when compared with those who did not, had a statistically significant lower plasma cortisol level and a smaller placenta, and presented a higher rate of low-birth-weight infants. Skin lightening is a common practice during pregnancy in Dakar, and the use of steroids may result in consequences in the mother and her child.

Podoconiosis: a tropical model for gene-environment interactions?

Abstract: Podoconiosis (endemic non-filarial elephantiasis) is a geochemical disease occurring in individuals exposed to red clay soil derived from alkalic volcanic rock. It is a chronic, debilitating disorder and a considerable public health problem in at least 10 countries in tropical Africa, Central America and northern India. Only a small proportion of individuals exposed to red clay develop disease and familial clustering of cases occurs, so we tested the hypothesis that disease occurs in genetically susceptible individuals on exposure to an environmental element in soil. Using multiple statistical genetic techniques we estimated sibling recurrence risk ratio (lambda(s)) and heritability for podoconiosis, and conducted segregation analysis on 59 multigenerational affected families from Wolaitta Zone, southern Ethiopia. We estimated the lambda(s) to be 5.07. The heritability of podoconiosis was estimated to be 0.629 (SE 0.069, P=1x10(-7)). Segregation analysis showed that the most parsimonious model was that of an autosomal co-dominant major gene. Age and use of footwear were significant covariates in the final model. Host genetic factors are important determinants of susceptibility to podoconiosis. Identification of the gene(s) involved will lead to better understanding of the gene-environment interactions involved in the pathogenesis of podoconiosis and other complex multifactorial conditions.

Brucellosis as a cause of acute febrile illness in Egypt.

Abstract: Summary To develop better estimates of brucellosis incidence, we conducted population-based surveillance for acute febrile illness (AFI) in Fayoum governorate (population 2 347 249), Egypt during two summer periods (2002 and 2003). All hospitals and a representative sample of community healthcare providers were included. AFI patients without obvious etiology were tested for brucellosis by culture and serology. Incidence estimates were calculated adjusting for sampling methodology and study period. Of 4490 AFI patients enrolled, 321 (7%) met the brucellosis case definition. The estimated annual incidence of brucellosis per 100 000 population was 64 and 70 in 2002 and 2003, respectively. The median age of brucellosis patients was 26 years and 70% were male; 53% were initially diagnosed as typhoid fever. Close contact with animals and consumption of unpasteurized milk products were associated with brucellosis. The high incidence of brucellosis in Fayoum highlights its public health importance, and the need to implement prevention strategies in humans and animals.

Effect of multiple interventions on community health workers' adherence to clinical guidelines in Siaya district, Kenya

Abstract: Evaluation of a community health worker (CHW) programme in Siaya district, Kenya, showed CHWs commonly made errors in managing childhood illness. We assessed the effect of multiple interventions on CHW healthcare practices. A sample of 192 ill-child consultations performed by 114 CHWs in a hospital outpatient department between February and March 2001 were analysed. The mean percentage of assessment, classification and treatment procedures performed correctly for each child was 79.8% (range 13.3-100%). Of the 187 children who required at least one treatment or referral to a health facility, only 38.8% were prescribed all treatments (including referral) recommended by the guidelines. Multivariate analyses found no evidence that the intervention-related factors studied (refresher training, supervision, involvement of community women in the CHW selection process, adequacy of medicine supplies, and use of a guideline flipchart during consultations) were significantly associated with overall or treatment-specific guideline adherence. A multivariate linear regression analysis revealed that several non-intervention-related factors, such as patient characteristics, were significantly associated with overall guideline adherence. Given that our study was cross-sectional and our measurement of exposure to several interventions was based on CHW recall, the estimated effects of the interventions should be interpreted with caution. Despite these limitations, however, our results raise questions about the effectiveness, in the setting of Siaya district, of several interventions commonly used to improve the quality of care given by CHWs.

Clinical and epidemiological characteristics of yellow fever in Brazil: analysis of reported cases 1998-2002

Abstract: Yellow fever (YF), an arboviral infection of major public health importance in Brazil, is associated with high mortality and high epidemic potential. We analysed confirmed YF cases from the National Surveillance System from 1998-2002 and assessed risk factors for death among hospitalised patients. Variables assessed included age, gender, clinical signs and laboratory findings. A logistic regression model was used to identify independent predictors of death among hospitalised patients. From 1998-2002, among 2117 suspected YF cases reported to Brazil's Ministry of Health, 251 (11.9%) had confirmed YF, of whom 217 (86.5%) were hospitalised and the case fatality rate was 44.2%. Factors associated with higher mortality in univariate analysis included male gender (relative risk (RR) 1.96, 95% CI 1.17-2.28), age >40 years (RR 2.61, 95% CI 1.25-5.45), jaundice (RR 2.66, 95% CI 2.12-3.35), serum aspartate aminotransferase (AST) >1200 IU/l (RR 1.84, 95% CI 1.23-2.74), alanine aminotransferase >1500 IU/l (RR 2.09, 95% CI 1.38-3.17), total bilirubin >7.0mg/dl (RR 2.33, 95% CI 1.44-3.78), direct bilirubin >5.0mg/dl (RR 2.29, 95% CI 1.33-3.94) and blood urea nitrogen >100mg/dl (RR 5.77, 95% CI 1.43-23.22). In multivariate analysis, elevated AST and jaundice remained independently associated with higher mortality. These findings suggest that selected clinical and laboratory indicators may help clinicians recognise potentially fatal cases of YF.