Showing papers in "Annals of Tropical Medicine and Parasitology in 2006"

Measuring the global burden of disease and epidemiological transitions: 2002--2030.

Abstract: Any planning process for health development ought to be based on a thorough understanding of the health needs of the population. This should be sufficiently comprehensive to include the causes of premature death and of disability, as well as the major risk factors that underlie disease and injury. To be truly useful to inform health-policy debates, such an assessment is needed across a large number of diseases, injuries and risk factors, in order to guide prioritization. The results of the original Global Burden of Disease Study and, particularly, those of its 2000-2002 update provide a conceptual and methodological framework to quantify and compare the health of populations using a summary measure of both mortality and disability: the disability-adjusted life-year (DALY). Globally, it appears that about 56 million deaths occur each year, 10.5 million (almost all in poor countries) in children. Of the child deaths, about one-fifth result from perinatal causes such as birth asphyxia and birth trauma, and only slightly less from lower respiratory infections. Annually, diarrhoeal diseases kill over 1.5 million children, and malaria, measles and HIV/AIDS each claim between 500,000 and 800,000 children. HIV/AIDS is the fourth leading cause of death world-wide (2.9 million deaths) and the leading cause in Africa. The top three causes of death globally are ischaemic heart disease (7.2 million deaths), stroke (5.5 million) and lower respiratory diseases (3.9 million). Chronic obstructive lung diseases (COPD) cause almost as many deaths as HIV/AIDS (2.7 million). The leading causes of DALY, on the other hand, include causes that are common at young ages [perinatal conditions (7.1% of global DALY), lower respiratory infections (6.7%), and diarrhoeal diseases (4.7%)] as well as depression (4.1%). Ischaemic heart disease and stroke rank sixth and seventh, retrospectively, as causes of global disease burden, followed by road traffic accidents, malaria and tuberculosis. Projections to 2030 indicate that, although these major vascular diseases will remain leading causes of global disease burden, with HIV/AIDS the leading cause, diarrhoeal diseases and lower respiratory infections will be outranked by COPD, in part reflecting the projected increases in death and disability from tobacco use.

Malaria and helminth interactions in humans: an epidemiological viewpoint

Abstract: In the tropics, helminths are among the most common chronic infections of humans and Plasmodium infections the most deadly. As these two groups of parasites have similar geographical distributions, co-infection is commonplace. It has increasingly been speculated that helminth infections may alter susceptibility to clinical malaria, and there is now increasing interest in investigating the consequences of co-infection, with studies yielding contrasting results. The immunological interactions between helminths and malarial parasites are unclear, although several hypotheses have been proposed. This review provides an epidemiological overview of the possible interactions between helminths and malarial parasites, in relation to geographical distributions and disease patterns, and provides a critical discussion of the results of the epidemiological studies that have so far been conducted to investigate the possible associations. Future studies that might be considered, in order to address the gaps in knowledge, are also considered.

An update on Chagas disease (human American trypanosomiasis)

Abstract: Human American trypanosomiasis or Chagas disease -- named after Carlos Chagas who first described it in 1909 -- exists only on the American continent. It is caused by a parasite, Trypanosoma cruzi, that is transmitted to humans by blood-sucking triatomine bugs, by blood transfusion, and transplacentally. Chagas disease has two, successive phases: acute and chronic. The acute phase lasts 6-8 weeks. After several years of starting the chronic phase, 20%-35% of infected individuals (the percentage varying with geographical area) develop irreversible lesions of the autonomous nervous system in the heart, the oesophagus, the colon and/or the peripheral nervous system. Data on the prevalence and distribution of Chagas disease markedly improved in quality during the 1980s, as a result of demographically representative, cross-sectional studies carried out in countries where no accurate information on these parameters was available. Experts had previously met in Brasilia, in 1979, and devised standard protocols for carrying out country-wide studies not only on the prevalence of human infection with T. cruzi but also on house infestation with the triatomine vectors. Thanks to a co-ordinated programme in the southernmost countries of South America (i.e.the 'Southern Cone'), transmission of T. cruzi by the vectors or blood transfusion has been successfully interrupted in Uruguay (from 1997), Chile (from 1999) and Brazil (from 2005), and the global incidence of new human infection with T. cruzi has decreased by 67%. Similar multi-country control initiatives have been launched in the Andean countries and in Central America, with the goal of interrupting all transmission of T. cruzi to humans by 2010 -- a goal set, in 1998, as a resolution of the World Health Assembly. Recent advances in basic research on T. cruzi include the genetic characterization of populations of the parasite and the sequencing of its genome.

Causes of acute, undifferentiated, febrile illness in rural Thailand: results of a prospective observational study

Abstract: The adult patients who, between July 2001 and June 2002, presented at any of five hospitals in Thailand with acute febrile illness in the absence of an obvious focus of infection were prospectively investigated Blood samples were taken from all of the patients and checked for aerobic bacteria and leptospires by culture In addition, at least two samples of serum were collected at different times (on admission and 2-4 weeks post-discharge) from each patient and tested, in serological tests, for evidence of leptospirosis, rickettsioses, dengue and influenza The 845 patients investigated, of whom 661 were male, had a median age of 38 years and a median duration of fever, on presentation, of 35 days Most (765%) were agricultural workers and most (683%) had the cause of their fever identified, as leptospirosis (369%), scrub typhus (199%), dengue infection or influenza (107%), murine typhus (28%), Rickettsia helvetica infection (13%), Q fever (1%), or other bacterial infection (12%) The serological results indicated that 103 (122%) and nine (1%) of the patients may have had double and triple infections, respectively Leptospirosis and rickettsioses, especially scrub typhus, were thus found to be major causes of acute, undifferentiated fever in Thai agricultural workers

A global assessment of closed forests, deforestation and malaria risk.

Abstract: Global environmental change is expected to affect profoundly the transmission of the parasites that cause human malaria. Amongst the anthropogenic drivers of change, deforestation is arguably the most conspicuous, and its rate is projected to increase in the coming decades. The canonical epidemiological understanding is that deforestation increases malaria risk in Africa and the Americas and diminishes it in South-east Asia. Partial support for this position is provided here, through a systematic review of the published literature on deforestation, malaria and the relevant vector bionomics. By using recently updated boundaries for the spatial limits of malaria and remotely-sensed estimates of tree cover, it has been possible to determine the population at risk of malaria in closed forest, at least for those malaria-endemic countries that lie within the main blocks of tropical forest. Closed forests within areas of malaria risk cover approximately 1.5 million km2 in the Amazon region, 1.4 million km2 in Central Africa, 1.2 million km2 in the Western Pacific, and 0.7 million km2 in South-east Asia. The corresponding human populations at risk of malaria within these forests total 11.7 million, 18.7 million, 35.1 million and 70.1 million, respectively. By coupling these numbers with the country-specific rates of deforestation, it has been possible to rank malaria-endemic countries according to their potential for change in the population at risk of malaria, as the result of deforestation. The on-going research aimed at evaluating these relationships more quantitatively, through the Malaria Atlas Project (MAP), is highlighted.

Chronic non-communicable diseases

Abstract: Chronic non-communicable diseases (NCD) account for almost 60% of global mortality, and 80% of deaths from NCD occur in low- and middle-income countries. One quarter of these deaths--almost 9 million in 2005--are in men and women aged <60 years. Taken together, NCD represent globally the single largest cause of mortality in people of working age, and their incidences in younger adults are substantially higher in the poor countries of the world than in the rich. The major causes of NCD-attributable mortality are cardiovascular disease (30% of total global mortality), cancers (13%), chronic respiratory disease (7%) and diabetes (2%). These conditions share a small number of behavioural risk factors, which include a diet high in saturated fat and low in fresh fruit and vegetables, physical inactivity, tobacco smoking, and alcohol excess. In low- and middle-income countries such risk factors tend to be concentrated in urban areas and their prevalences are increasing as a result of rapid urbanization and the increasing globalisation of the food, tobacco and alcohol industries. Because NCD have a major impact on men and women of working age and their elderly dependents, they result in lost income, lost opportunities for investment, and overall lower levels of economic development. Reductions in the incidences of many NCD and their complications are, however, already possible. Up to 80% of all cases of cardiovascular disease or type-2 diabetes and 40% of all cases of cancer, for example, are probably preventable based on current knowledge. In addition, highly cost-effective measures exist for the prevention of some of the complications of established cardiovascular disease and diabetes. Achieving these gains will require a broad range of integrated, population-based interventions as well as measures focused on the individuals at high risk. At present, the international-assistance community provides scant resources for the control of NCD in poor countries, partly, at least, because NCD continue to be wrongly perceived as predominantly diseases of the better off. As urbanization continues apace and populations age, investment in the prevention and control of NCD in low-and middle-income countries can no longer be ignored.

Climate change and health: global to local influences on disease risk.

Abstract: The World Health Organization has concluded that the climatic changes that have occurred since the mid 1970s could already be causing annually over 150,000 deaths and five million disability-adjusted life-years (DALY), mainly in developing countries. The less developed countries are, ironically, those least responsible for causing global warming. Many health outcomes and diseases are sensitive to climate, including: heat-related mortality or morbidity; air pollution-related illnesses; infectious diseases, particularly those transmitted, indirectly, via water or by insect or rodent vectors; and refugee health issues linked to forced population migration. Yet, changing landscapes can significantly affect local weather more acutely than long-term climate change. Land-cover change can influence micro-climatic conditions, including temperature, evapo-transpiration and surface run-off, that are key determinants in the emergence of many infectious diseases. To improve risk assessment and risk management of these synergistic processes (climate and land-use change), more collaborative efforts in research, training and policy-decision support, across the fields of health, environment, sociology and economics, are required.

Phlebotomus (Paraphlebotomus) alexandri: a probable vector of Leishmania infantum in Iran.

Abstract: The incidence of human visceral leishmaniasis (VL) caused by Leishmania infantum, which is endemic in several parts of Iran, has recently increased in the Nourabad-Mamassani district of Fars province, in the south of the country. Between 2003 and 2005, 12,688 sandflies were caught in this focus, using CDC miniature light traps, sticky traps and aspirators, in an attempt to identify the main vector of L. infantum. When 120 of the parous, female Phlebotomus (Paraphlebotomus) alexandri caught were individually checked for Leishmania infection, in an assay based on PCR and kinetoplast minicircle primers (LINR4 and LIN17), five (4.2%) of the flies were found to be infected with L. infantum. Thirty-nine (32.5%) of the 120 blood-fed Ph. alexandri checked in an ELISA were found positive for human blood. Since Ph. alexandri was the third-most common species caught (representing over 17% of the total catch), was clearly anthropophilic, and was not infrequently infected with L. infantum, it is probably an important vector in the Nourabad-Mamassani focus. Although other sandfly species have been found naturally infected with promastigotes in Iran, Ph. alexandri is the first that has been proven to harbour L. infantum in the country.

Schistosoma mansoni in infants (aged < 3 years) along the Ugandan shoreline of Lake Victoria.

Abstract: In two complementary epidemiological surveys of villages on the Ugandan shoreline of Lake Victoria, the putative occurrence of intestinal schistosomiasis in the local infants (children aged < 3 years) was investigated. When, during the first survey, 136 mother-and-infant pairs from a total of 12 villages were studied, only 7% of the infants but 45% of the mothers were found to be egg-patent for Schistosoma mansoni infection. The use of dipstick tests for urine-circulating cathodic antigen indicated, however, a much higher prevalence, of approximately 40%, among the infants. In the second survey, urine samples and multiple, not single, stool samples were collected from another 19 mother-and-infant pairs in two of the 12 study villages (Bugoto and Bwondha), and a standardized questionnaire was implemented. The prevalence of egg-patent infection was then found to be markedly higher in the study infants from Bugoto (86%) than in those from Bwondha (25%). A greater level of mother-and-infant water contact, a higher abundance of (infected) Biomphalaria choanomphala, and an unusual lakeshore topology may explain why S. mansoni infection was so much more common in the Bugoto subjects than in the Bwondha. All but one of the infants studied in the second survey were found to be anaemic (with <110 g haemoglobin/litre). Taken together, these children were less likely to be found infected with hookworm (16%), Hymenolepis nana (11%) or Trichuris trichiura (5%) than with S. mansoni (47%). Infection with the parasites causing intestinal schistosomiasis can be common among the infants living in these lakeshore villages. Although the immediate and later-life clinical impacts of such infection have yet to be elucidated, such infants would probably benefit from regular de-worming. Mothers should be strongly encouraged to visit the nearest health-services clinic, with their infants, for any necessary anthelmintic treatment.

Urbanization and tropical health — then and now

Abstract: Since the launch of the Annals of Tropical Medicine and Parasitology 100 years ago, the percentage of the world's population living in urban settings has more than tripled and is now approaching 50%. Urbanization will continue at a high pace, particularly in the less developed regions of Africa and Asia. The profound demographic, ecological and socio-economic transformations that accompany the process of urbanization have important impacts on health and well-being. In industrialized countries, urbanization led to the so-called 'epidemiological transition', from acute infectious and deficiency diseases to chronic non-communicable diseases, many decades ago. In the developing world, surprisingly little research has been carried out on the health-related aspects of urbanization. In a temporal analysis of publications in the Annals of Tropical Medicine and Parasitology, for example, in which the first volume in every decade from 1907 was examined, only 16 (2.6%) of the 604 articles investigated focused on epidemiological and/or public-health issues in urban tropical settings. This review begins with the question 'what is urban?' and then provides a summary of the trends seen in urbanization, and its impacts on human health, over the past century, on both a global and regional scale. For the main tropical diseases, estimates of the at-risk populations and the numbers of cases are updated and then split into urban and non-urban categories. The inhabitants of urban slums are particularly vulnerable to many of these diseases and require special attention if internationally-set targets for development are to be met. Heterogeneity, a major feature of urban settings in the tropics that complicates all efforts at health improvement, is demonstrated in an exploration of a densely populated municipality of a large West African town. Urban planners, public-health experts and other relevant stakeholders clearly need to make much more progress in alleviating poverty and enhancing the health and well-being of urban residents, in an equity-effective and sustainable manner.

Comparison of the Paracheck-Pf test with microscopy, for the confirmation of Plasmodium falciparum malaria in Tanzania.

Abstract: Paracheck-Pf is a rapid, qualitative immuno-assay for the detection of Plasmodium falciparum-specific histidine-rich protein-2 in samples of human blood. The assay has now been evaluated, against the usual 'gold standard', microscopy, using blood samples from 1655 individuals in five districts of Tanzania, four of which experience frequent malaria outbreaks. The aim was to verify whether Paracheck-Pf could be a reliable tool for the confirmation of malaria outbreaks in such areas. The overall measurements of the assay's performance were good, with a sensitivity of 90.0%, a specificity of 96.6%, a positive predictive value of 88.9%, and a negative predictive value of 97.0% (with an estimated malaria prevalence of 23.3%). There was, however, marked variation between the study districts, the assay's performance being relatively poor where the test had been stored for 12 months at room temperature (23.5±3.5°C). The assay was easy to perform in the field and could clearly be a valuable tool in remote a...

Aedes aegypti (Diptera: Culicidae) production from non-residential sites in the Amazonian city of Iquitos, Peru.

Abstract: Programmes for the surveillance of Aedes aegypti (L.) often focus on residential areas, ignoring non-residential sites. Between November 2003 and October 2004, pupal/demographic surveys were therefore conducted in non-residential sites in the Peruvian city of Iquitos. The sampled sites included schools, factories, ports, public markets, petrol stations, commercial zones, airports, government buildings, animal-production areas, and recreational areas. Compared with the residential sites that had been surveyed a few years earlier, the non-residential sites generally had fewer pupae/ha, even though pupae were found in a high percentage of the sites investigated. Nonetheless, although 70% of pupal production was outdoors. In commercial areas, 41% of the pupae came from manually-filled containers, compared with <12% in residential sites. These results indicate that non-residential sites can be highly productive for Ae. aegypti and that the role of such sites in dengue transmission requires further investigation.

Quality of treatment for febrile illness among children at outpatient facilities in sub-Saharan Africa

Abstract: For the prompt and effective management of malaria cases (a key strategy for reducing the enormous burden of the disease), healthworkers must prescribe antimalarial drugs according to evidence-based guidelines. In sub-Saharan Africa, the guidelines for use in outpatient settings generally recommend that febrile illness in children should be suspected to be malaria and be treated with an antimalarial drug. The quality of treatment offered to febrile children at outpatient facilities in this region has now been investigated in a literature review. The results of five methodologically comparable studies were also used to explore the determinants of malaria-treatment practices. The quality of treatment prescribed to febrile children was found to have been generally sub-optimal, with low levels of adherence to national guidelines, the frequent selection of non-recommended antimalarials, and the use of incorrect dosages. Several factors might be to responsible for these shortcomings. Although interventions such as the Integrated Management of Childhood Illness (IMCI) strategy can lead to improvements, a better understanding of the practices of the healthworkers responsible for treating febrile children will be needed before treatment is made much better. The failure to provide treatment of good quality will become an increasingly important problem as antimalarial policies involving drugs with more complex dosing regimens, such as artemisinin-based combination therapies (ACT), are implemented. If the malaria burden in Africa is to be greatly reduced, the deployment of ACT must be accompanied by interventions to ensure the correct treatment of children at the point of care. Some interventions, such as IMCI, can improve the treatment of not only malaria but also other potentially life-threatening illnesses.

The in-vivo antimalarial activities of Uvaria chamae and Hippocratea africana.

Abstract: The antimalarial activities of ethanolic root extracts of two plants used traditionally as malarial remedies in southern Nigeria, Uvaria chamae (Annonaceae) and Hippocratea africana (Hippocrateaceae), were studied in vivo, in mice infected with Plasmodium berghei berghei. The extract of U. chamae, when given orally at 300-900 mg/kg.day, exhibited significant antimalarial activity against both early and established infections. When established infections were treated, the mean survival time of the mice observed with this extract at 900 mg/kg.day was similar to that seen with the positive control: chloroquine at 5 mg/kg.day. The extract of H. africana, tested at oral doses of 200-600 mg/kg.day, also demonstrated promising blood schizontocidal activity, both in early and established infections. Although the question of their toxicities has still to be fully addressed, it is clear that both U. chamae and H. africana possess considerable antimalarial activity and they, or drugs based on their antimalarial constituents, may prove useful in the treatment of human malaria.

Carriage by the German cockroach (Blattella germanica) of multiple-antibiotic-resistant bacteria that are potentially pathogenic to humans, in hospitals and households in Tripoli, Libya

Abstract: Using standard bacteriological procedures, 403 cockroaches (Blattella germanica) collected in Tripoli, from hospitals or the households surrounding the hospitals, were examined for bacteria that are potentially pathogenic to humans. Almost all of the cockroaches (96.1% of the 253 from hospitals and 98.7% of the 150 from households) were found to be carrying potentially pathogenic bacteria, with similar mean burdens of 3.2 × 105 colony-forming units (cfu) (range=0–1.4 × 107) for each hospital cockroach and 1.9 × 105 cfu (range=0–3.1 × 106) for each household cockroach (P>0.05). Overall, 27 and 25 species of potential pathogen were isolated from the hospital and household cockroaches, respectively, with Klebsiella, Enterobacter, Serratia and Streptococcus predominant. Carriage of species of Serratia was significantly more common among the hospital cockroaches than among the household cockroaches, whereas carriage of Klebsiella, Enterobacter, Citrobacter and Aeromonas was significantly more common am...

Echinococcosis: historical landmarks and progress in research and control.

Abstract: Although hydatid cysts were recognised and described in ancient times, in both livestock and humans, it was not until the 17th Century that their biological nature began to be understood. The past ...

Towards the elimination of onchocerciasis.

Abstract: Human onchocerciasis is a severely disabling filarial disease that is endemic in 28 African countries, six Latin American countries and Yemen. The disease causes a high burden of blindness and visual loss, along with itching and other severe dermal manifestations. It constitutes a significant obstacle to socio-economic development in highly endemic riverine areas, where the Simulium blackflies that act as vectors breed. Onchocerciasis has been subject to control efforts for more than 50 years, initially mainly through vector control but since 1988, with free access to ivermectin (Mectizan), also through large-scale chemotherapy. The Onchocerciasis Control Programme in West Africa operated successfully from 1974 to 2002 in 11 countries, covering the worst savannah foci of the disease through vector control and, in its later stages, also through ivermectin distribution. The African Programme for Onchocerciasis Control was established in 1995, to cover the remaining endemic areas in Africa, with the sustainable annual distribution of ivermectin by 2010 its main goal. Meanwhile, the Onchocerciasis Elimination Program for the Americas is making rapid progress in the virtual regional elimination of the disease through ivermectin distribution, which is achievable primarily because the vectors in the western hemisphere are less efficient than those elsewhere. The global elimination of onchocerciasis as a public-health problem is now within reach but this will require long-term strategies to secure the great gains made so far, through ivermectin treatment and local vector control. Research is needed to define the optimal approaches with the existing tools and to intensify the development of alternative strategies, such as macrofilaricidal drugs for wide-scale use.

Pupal/demographic surveys to inform dengue-vector control.

Abstract: ‘Standard’ entomological indicators of the abundance of the urban yellow-fever and dengue vector were developed primarily for monitoring the progress of the Aedes aegypti eradication campaign in the Americas, which was launched by the Pan American Health Organization in the late 1940s. The three classic Stegomyia indices — the house (or premises) index, the container index, and the Breteau index — are all based on the presence or absence of immature stages of the vector in water-holding containers and confined natural habitats close to or inside dwellings or other buildings. With eradication as the public-health objective, the success of the national and international campaigns was measured in terms of the complete absence of Ae. aegypti. Subsequent surveillance and vector-control responses were necessary to ensure the rapid detection and elimination of any re-infestations. For the purposes of campaign management, the Stegomyia indices were largely satisfactory, although ovitraps were later introduced as an additional and more sensitive method for detecting the presence of Ae. aegypti in neighbourhoods where vector densities had been reduced to very low levels. With the abandonment of the hemispheric eradication campaign in 1985, the overwhelming majority of Ae. aegypti programmes in the Americas became de-facto control programmes, having much in common with those being carried out elsewhere in the tropics and subtropics. The responsibility of such programmes thus became, and remains, the cost-effective utilization of available resources to reduce vector populations to levels at which they are no longer of significant public-health importance. It became increasingly evident, however, that the Stegomyia indices were largely inadequate to the task of defining those levels and answering the question, for a given epidemiological situation, of how much vector control would be needed to reduce, interrupt or prevent viral transmission. That the traditional indices are a poor proxy for measuring adult abundance and are of limited use in assessing transmission risk was acknowledged in 1999, at a World Health Organization informal consultation on strengthening the implementation of the global strategy for the prevention and control of dengue fever and dengue haemorrhagic fever (WHO, 2000). The attendees at this consultation recommended ‘the refinement of existing indicators and/or the development of new indicators that better reflect transmission potential’. There followed a review, commissioned by the UNICEF/ UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR), of the entomological sampling methods and indicators for dengue vectors (Focks, 2003). The pupalsurvey technique was considered to be a promising method for identifying the most adult-productive container habitats in various ecological settings where dengue is an important public-health problem, and one with the potential for guiding programme managers in the application of more costeffective, targeted approaches to vector control. Moreover, it was envisaged that pupal surveys, if combined with the collection of demographic data, could help elucidate the transmission dynamics of dengue, identify transmission risk, and quantify and validate target levels of vector abundance. The TDR subsequently funded a multicountry project to validate the reliability and practicality of the pupal-survey technique. Theproject involvedstudies inninecountries on Annals of Tropical Medicine & Parasitology, Vol. 100, Supplement No. 1, S1–S3 (2006)

Pupal-productivity surveys to identify the key container habitats of Aedes aegypti (L.) in Barranquilla, the principal seaport of Colombia.

Abstract: Surveys were conducted in three neighbourhoods of Barranquilla, the main seaport of Colombia, to identify, using counts of pupae in water containers during the wet and dry seasons, the most productive Aedes aegypti breeding sites. Overall, 3,433 premises were investigated in the wet season and 3,563 in the dry, representing, respectively, 82.3% and 84.6% of the total numbers of premises in the study areas. Despite a reasonably reliable supply of piped water, there were still some large storage containers for domestic water (cement ground tanks and plastic, metal and cement drums) in the area. Although such containers represented only 1.8%-16.3% of the total number of containers observed, they contributed 72.0%-78.2% and 65.0%-95.8% of the total Ae. aegypti pupal population in the three study neighbourhoods during the wet and dry seasons, respectively. In contrast, bottles represented 23.0%-88.9% of the total number of containers but produced no more than 0.1% of the total Ae aegypti pupal populations in these neighbourhoods. Other containers (tyres, vases, 'other discarded' and 'other used') generally produced only low numbers of pupae. In some settings, however, containers in the 'other discarded' category could contribute up to 19% of the total pupal population, and in one survey of one neighbourhood a single container in this category held 9.1% of all the pupae collected. These results, from a city where dengue fever is endemic, will help to focus local campaigns for Ae. aegypti source-reduction on the most productive categories of container.

Health, development and the Millennium Development Goals

Abstract: The Millennium Development Goals (MDG), which emerged from the United Nations Millennium Summit in 2000, are increasingly recognized as the over-arching development framework. As such, the MDG are increasingly guiding the policies of poor countries and aid agencies alike. This article reviews the challenges and opportunities for health presented by the MDG.The opportunities include that three of the eight MDG relate to health — a recognition that health is central to global agenda of reducing poverty, as well as an important measure of human well-being in its own right. A related point is that the MDG help to focus attention on those health conditions that disproportionally affect the poor (communicable disease, child health and maternal health), which should, in turn, help to strengthen the equity focus of health policies in low-income countries. Further, because the MDG are concrete, it is possible to calculate the cost of achieving them, which in turn strengthens the long-standing calls for hig...

Comparison between one and two injections of pentamidine isethionate, at 7 mg/kg in each injection, in the treatment of cutaneous leishmaniasis in French Guiana.

Abstract: In a retrospective study set in French Guiana, the efficacy and tolerance of the intramuscular treatment of cutaneous leishmaniasis (CL) with a single injection of pentamidine isethionate, at 7 mg/kg, were compared with those observed, earlier, using two such injections (given 48 h apart). Although 83.6% of the 281 patients given two injections each were cured, the single-injection protocol was generally as effective, curing 78.8% of 137 patients. The single-injection protocol was also associated with fewer adverse effects than the two-injection. In the treatment of "difficult" cases (those with satellite papules or relatively high numbers of amastigotes in their lesions), however, the two-injection protocol appeared significantly more effective than the single-injection. In French Guiana, therefore, patients with CL should be given one injection with pentamidine isethionate and only be given a second, 48 h later, if they have satellite papules and/or relatively high numbers of amastigotes in their lesions.

The chequered history of malaria control: are new and better tools the ultimate answer?

Abstract: Following Ronald Ross' demonstration in 1897 that mosquitoes transmit malarial parasites, efforts to control malaria were naturally focussed on attacking the mosquito vector by various measures, mainly directed against the aquatic stages. Although the results were spectacular in some areas, there was a growing realisation that effective control of malaria depended on other factors, including the availability of better drugs than quinine and a greater understanding of the epidemiology of the disease under various environmental conditions. With the discovery of DDT, an all-out effort was made to eradicate malaria by attacking adult mosquitoes. Eradication was not achieved in many countries, mainly because of inadequate health infrastructures. With the emergence of chloroquine-resistant parasites, the search for more effective drug regimens intensified, various drugs and drug combinations were assessed, and methods were developed to monitor and assess degrees of resistance. Since resistance to drugs can develop very quickly, the use of drug combinations, especially those containing artemisinin derivatives, is now recommended. Insecticide-impregnated bednets have become the preferred method of vector control. Although the search for better tools must continue, the events of the past century emphasise the need to strengthen health systems to ensure that they are capable of delivering effective interventions and of assessing their effectiveness in controlling malaria.

Aedes aegypti pupal/demographic surveys in southern Mexico: consistency and practicality

Abstract: In interventions aimed at the control of the immature stages of Aedes aegypti (L.), the principal vector of the dengue viruses, attempts are often made to treat or manage all larval habitats in households. When there are resource-constraints, however, a concentration of effort on the types of container that produce the most pupae may be required. Identification of these 'key' container types requires surveys of the immature stages and particularly — since these give the best estimates of the numbers of adults produced — of the numbers of pupae in local containers. Although there has been no clearly defined or standardized protocol for the sampling of Ae. aegypti pupae for many years, a methodology for 'pupal/demographic' surveys, which may allow the risk of dengue outbreaks in a given setting to be estimated, has been recently described. The consistency and practicality of using such surveys has now been investigated in three cities in the Mexican state of Chiapas, Mexico. Using a combination of '...

Rickettsiae of the spotted-fever group in ixodid ticks from Hungary: Identification of a new genotype ('Candidatus Rickettsia kotlanii')

Abstract: Three common European 'anthrophilic' ticks, Ixodes ricinus, Haemaphysalis concinna and Dermacentor reticulatus, were collected in Hungary and tested, in assays based on nested PCR, for rickettsiae of the spotted-fever group. Low percentages of I. ricinus (2.7%) and H. concinna (1.0%) and a high percentage of D. reticulatus (26.8%) were found to be infected. The rickettsiae in the ticks were then identified, by sequencing of the genes coding for 16S ribosomal RNA (16S rDNA), citrate synthase (gltA) and the rOmpA outer-membrane protein (ompA), as Rickettsia helvetica, Rickettsia monacensis, Rickettsia sp. RpA4, or what is probably a newly recognized Rickettsia species ('Candidatus Rickettsia kotlanii'). These results raise the possibility that rickettsiae other than Rickettsia slovaca are involved in human disease in Hungary. Current knowledge on the distributions of the rickettsiae of the spotted-fever group that are emerging in Europe is also summarized.

The in-vitro antimicrobial activities of some medicinal plants from Cameroon.

Abstract: The antimicrobial activities of 10 plant species (Voacanga africana, Crepis cameroonica, Plagiostyles africana, Crotalaria retusa, Mammea africana, Lophira lanceolata, Ochna afzelii, Ouratea elongata, Ou. flava and Ou. sulcata), each of which is currently used in the traditional medicine of Cameroon, were investigated in vitro. The activities of a methanol extract of each plant were tested, in disc-diffusion assays, against 37 reference or laboratory strains of seven species of microorganism (Staphylococcus aureus, S. epidermidis, Enterococcus hirae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Candida albicans). The minimal inhibitory concentrations of each extract were then estimated, against each of the more susceptible microorganisms (i.e. those giving an inhibition zone measuring at least 9 mm in diameter in the disc-diffusion assays), by agar dilution. Although, in the disc-diffusion assays, each of the 10 methanol extracts investigated displayed some degree of antimicrobial activity against at least one species of microorganism, no activity against the Gram-negative bacteria (Es. coli, K. pneumoniae and Ps. aeruginosa) was observed. The extract with the greatest antimicrobial activity was that of Pl. africana (Euphorbiaceae).

Successful miltefosine treatment of post-kala-azar dermal leishmaniasis occurring during antiretroviral therapy

Abstract: The first two patients to be treated with miltefosine for post-kala-azar dermal leishmaniasis (PKDL) are reported. One was a 26-year-old Ethiopian man who had been treated with sodium stibogluconate, for relapsing visceral leishmaniasis (VL), four times between August 2002 and March 2004. In January 2004 this patient was found to be seropositive for HIV and began antiretroviral treatment with stavudine, lamivudine and nevirapine. Five months later he developed clinical PKDL, with extensive cutaneous, conjunctival and oral mucosal involvement. The second patient was a 42-year-old Ethiopian man who was treated for relapsing VL in November 2003. He too was subsequently found to be seropositive for HIV and was treated with stavudine, lamivudine and nevirapine from May 2004. He developed a nodular rash of PKDL over his face and upper body 2 weeks after starting the antiretroviral therapy. Treatment of both patients with oral miltefosine, at 100 mg/day for 28 days, led to the complete regression of their PKDL lesions. When checked 3-6 months after the end of the miltesofine treatment, neither patient showed any signs of VL, PKDL or other HIV-associated disease.

Application of the pupal/demographic-survey methodology in an area of Havana, Cuba, with low densities of Aedes aegypti (L.).

Abstract: Between the April and December of 2004, an Aedes aegypti (L.) pupal/demographic survey was conducted in the Playa municipality of Havana. The aims were to identify the key types of container in the production of the adult mosquitoes (and so provide a basis for targeted control) and assess transmission risk in terms of the number of pupae/person. Pupal abundance, as measured in the survey, was compared with traditional Stegomyia indices. The immature stages of Ae. aegypti were only found in 70 of the 15,153 containers that were investigated and the pupae of this species were only seen in 52 of the containers. Ground-level water-storage tanks yielded 74.1% of all the pupae, with a further 19.0% found in miscellaneous small containers. The utility of the pupal/demographic-survey methodology in the evaluation of dengue risk in the study area, and other areas of Cuba with low densities of Ae. aegypti, is discussed.

Use of the pupal/demographic-survey technique to identify the epidemiologically important types of containers producing Aedes aegypti (L.) in a dengue-endemic area of Venezuela.

Abstract: As dengue continues to emerge as a major public-health problem world-wide, efforts to control the dengue vector Aedes aegypti must become more effective and efficient. Results from larval and pupal surveys applied in Venezuela illustrate the uniqueness of the information gained from pupal surveys; information that is lost when traditional Stegomyia indices are calculated. As most Ae. aegypti pupae will emerge to become adults, controlling the containers that produce the most pupae could have the greatest impact on the adult population. Pupal-survey results in Venezuela showed that large (150- to 200-litre) water drums produce the greatest number of pupae throughout the year. In the rainy season, approximately 70% of all pupae are found in these drums or in tyres, buckets and tanks. Over 80% of pupae in the dry season are found in drums and tanks alone. By targeting only those domestic breeding containers that produce the greatest number of pupae, control efforts may be streamlined to have the greatest impact on reducing the local adult Ae. aegypti population.

Taenia solium: the complex interactions, of biological, social, geographical and commercial factors, involved in the transmission dynamics of pig cysticercosis in highly endemic areas

Abstract: If a programme for the control of pig cysticercosis is to be effective it has to be based on good data on the local epidemiology of Taenia solium. In 2002-2003, in a cross-sectional study of pig cysticercosis in the Mexican state of Morelos, 1747 pigs that had been born and reared in rural areas of the state were checked for T. solium infection by tongue inspection. The prevalence of cysticercosis in the pigs was found to vary from 0% to 30% according to the municipality from which the pigs came. Although prevalence appeared to be unaffected by the socio-economic status of the municipality, it was relatively high in areas that lacked latrines, and in pigs that were castrated, pregnant and/or of the native (rather than an imported) breed. The results of questionnaire-based interviews with pig owners revealed that most (64.5%) of the rural pigs, whether infected or not, are slaughtered and consumed within the locality where they were reared. The other pigs are sold at low prices to organised traffickers who take the uninspected pigs to neighbouring urban areas for sale. The observed complexity in the factors affecting the transmission of T. solium to the pigs of Morelos state calls for an intervention strategy of matching complexity, initially targeted at those villages with the highest prevalences of pig cysticercosis. The road transport of pigs needs to be better regulated, and the vaccination and genetic improvement of the rural pigs, and delaying the castration of the boars, should all be considered.

A century of smoke.

Abstract: Tobacco kills 5 million people annually. By the mid 2020s, that figure will increase to about 10 million a year, with most of the deaths occurring in developing countries. This review explains how early technological and regulatory developments contributed to the epidemic, reveals the efforts of the tobacco industry to conceal its products' harmfulness, and stresses the role of the globalization of trade and marketing as a means of increasing consumption world-wide. The results of tens of thousands of studies published globally over the past 50 years point to an association between smoking and lung cancer and other adverse health effects, and the non-smoker's rights movement has exposed the wide-spread perils of 'secondhand' smoke. Yet, the tobacco industry continues its global expansion, and consumers in low- and middle-income countries are especially susceptible to its marketing tactics. This review ends by emphasising the need for a global public-health response, and identifies the Framework Convention on Tobacco Control as a significant effort. It stresses the need for accelerated action and innovative tobacco-control efforts, if the projected death toll is to be reduced in this century.