Showing papers in "Annals of Tropical Medicine and Parasitology in 2002"
TL;DR: The GPELF has developed during an era of considerable change in international health policy, and can contribute to the relief of poverty, as LF is closely associated with low-income communities in the least developed countries and MDA is a pro-poor intervention.
Abstract: The Global Programme to Eliminate Lymphatic Filariasis (GPELF) is an innovative, public-private partnership for health improvement. The progress made since the programme was initiated, in 1998, is here reviewed. The programme is largely based on the regular mass administration of albendazole with either ivermectin (Mectizan(R)) or diethylcarbamazine. Both albendazole and ivermectin have been donated by their manufacturers, for as long as necessary. The first national campaigns based on these drugs commenced in late 1999. Since then, rapid progress has been made in confirming the safety of the drug combinations, establishing a regional approach, and recognizing that experiences, epidemiological settings, health systems, the best drug combinations and disease burdens all vary with the country involved. There is a continuing trend towards decentralization, and this should lead to greater regional and national ownership and more inter-country activities. The progress made in mapping the geographical distribution of lymphatic filariasis (LF), by designated implementation units and, ultimately, by country, is also summarized. Country-specific methods of social mobilization and drug distribution, that are compatible with health planning at central and district level, need to be developed. However, the assessment of coverage by mass drug administration (MDA) needs to be strengthened, to allow reliable national monitoring and inter-country or inter-region comparisons. Valuable contributions made by non-governmental development organizations (NGDO) and civil society organizations (CSO) are acknowledged, such organizations (and particularly local NGDO) should be encouraged to help more in implementing the various activities at district level. The GPELF has developed during an era of considerable change in international health policy. The programme can contribute to the relief of poverty, as LF is closely associated with low-income communities in the least developed countries and MDA is a pro-poor intervention. There are clear opportunities for linking the activities of the GPELF (which uses cheap or free drugs that bring considerable incidental health benefits, in addition to arresting the transmission of the parasites causing LF) with other health interventions. New evidence indicates that annual treatments with antifilarial drugs greatly reduce the clinical abnormalities of the disease. The programme has expanded rapidly, with the annual number of people treated rising from 2.9 million (in 12 countries) in the year 2000 to 25.89 million (in 22 countries) in 2001 and an estimated 80 million (in 34 countries) in 2002. At the recent meeting of the Global Alliance, held in New Delhi in May 2002, a significant but realistic challenge - of scaling-up the programme to cover up to 350 million of those at risk, by the end of 2005 - was set. The rate of growth necessary to meet this target presents considerable strategic and managerial challenges to all of the partners involved in the programme, from the development of synergies with other, large-scale, public-health interventions to the logistics of drug manufacture, shipping and local transportation and resolving the problems of social mobilization, reporting, evaluation and monitoring on such a scale. Such challenges are, however, easily outweighed by the potential benefits of success. If the international health community cannot provide the necessary support to complement the investments being made by the endemic countries (as they scale-up their LF-elimination campaigns and ensure yearly access to two free and efficacious drugs that bring major benefits to those treated), significant progress in the control of other infectious diseases becomes a very distant goal.
166 citations
TL;DR: This review describes the application of the REMO/GIS technique by APOC in its operations, and identifies the remaining related challenges.
Abstract: One of the fundamental challenges that the African Programme for Onchocerciasis Control (APOC) has had to face is how to identify the endemic communities where its mass ivermectin-treatment operations are to be carried out in conformity with its stated objective of targetting the most highly endemic, affected and at-risk populations. This it has done by adopting a technique, known as the rapid epidemiological mapping of onchocerciasis (REMO), that provides data on the distribution and prevalence of onchocerciasis. Integration of the REMO data into a geographical information system (GIS) enables delineation of zones of various levels of endemicity, and this is an important step in the planning process for onchocerciasis control. Zones are included in (or excluded from) the APOC-funded programme of community-directed treatment with ivermectin (CDTI), depending on whether or not their levels of onchocercal endemicity reach the threshold set by APOC. This review describes the application of the REMO/GIS technique by APOC in its operations, and identifies the remaining related challenges.
132 citations
TL;DR: The results indicate that bancroftian filariasis is more widely distributed in arid areas of Burkina Faso than hitherto recognized and that the prevalences of infection have remained fairly stable for at least 30 years.
Abstract: The geographical distribution of human infection with Wuchereria bancrofti was investigated in four West African countries (Benin, Burkina Faso, Ghana and Togo), using a commercial immunochromatographic test for filarial antigen. Efforts were made to cover each health-system implementation unit and to ensure no sampling point was >50 km from another, but otherwise the 401 study communities were selected at random. The aim was to enable spatial analysis of the data, to provide a prediction of the overall spatial relationships of the infection. The results, which were subjected to an independent random validation in Burkina Faso and Ghana, revealed that prevalence in the adult population of some communities exceeded 70% and that, over large areas of Burkina Faso, community prevalences were between 30% and 50%. Most of Togo, southern Benin and much of southern Ghana appeared completely free of the infection. Although there were foci on the Ghanaian coast with prevalences of 10%-30%, such high prevalences did not extend into coastal Togo or costal Benin. The prevalence map produced should be useful in prioritizing areas for filariasis control, identifying potential overlap with ivermectin-distribution activities undertaken by onchocerciasis-control programmes, and enabling inter-country and sub-regional planning to be initiated. The results indicate that bancroftian filariasis is more widely distributed in arid areas of Burkina Faso than hitherto recognized and that the prevalences of infection have remained fairly stable for at least 30 years. The campaign to eliminate lymphatic filariasis as a public-health problem in Africa will require significantly more resources (human, financial, and logistic) than previously anticipated.
116 citations
TL;DR: PCR-based investigations appear to offer an effective method to confirm suspected cases of cutaneous leishmaniasis using (even archived) samples that have been collected, from humans (and reservoir hosts) in the field, by simple methods.
Abstract: DNA was isolated from 92 Giemsa-stained smears of lesions from suspected cases of cutaneous leishmaniasis and used for PCR-based diagnosis of Leishmania infection Each smear had been examined unde
111 citations
TL;DR: Although 334 of the samples were found to be culture-positive, the parasites were only detected in 142 of the simple smears, and faecal concentration led to an even lower sensitivity, in-vitro cultivation does seem worthwhile in the detection of B. hominis carriage in field studies.
Abstract: Currently, the detection of human infection with Blastocystis hominis is usually based on the examination under a light microscope of faecal samples, either directly, as 'simple smears', or after some form of concentration. Whether short-term, in-vitro cultivation would increase the sensitivity of such detection remains a matter of controversy. Over 900 fresh stool specimens, from soldiers in the Royal Thai Army, were each checked for the parasite using three methods: simple smears; formalin-ethyl-acetate concentration; and cultivation in Jones' medium. Although 334 of the samples were found to be culture-positive, the parasites were only detected in 142 of the simple smears, and faecal concentration led to an even lower sensitivity (64 positive samples). In-vitro cultivation does seem worthwhile in the detection of B. hominis carriage in field studies.
109 citations
TL;DR: If applied in a practical clinical setting (on symptomatic patients in whom active VL is suspected and other common infections have been excluded), strip testing of serum for anti-K39 antibody should be both sensitive and specific for diagnosing VL in India.
Abstract: Stored sera from 429 Indian subjects were assayed to extend the analysis of the accuracy of immunochromatographic strip-test detection of anti-K39 antibody in the non-invasive diagnosis of visceral leishmaniasis (VL). All 225 samples from patients with proven Leishmania infection tested positive [estimated sensitivity=100%; 95% confidence interval (CI)=98%-100%]. Sera from 99 of the 100 symptomatic patients with other diseases were non-reactive (estimated specificity=99%; CI=94%-100%). However, samples from 13 of the 104 apparently healthy controls showed positive strip-test results (estimated specificity=88%; CI=79%-93%), yielding an overall specificity of 93% (190/204; CI=88%-96%). If applied in a practical clinical setting (on symptomatic patients in whom active VL is suspected and other common infections have been excluded), strip testing of serum for anti-K39 antibody should be both sensitive and specific for diagnosing VL in India.
109 citations
TL;DR: The results of a multivariate logistic regression analysis showed that, at the individual level, the presence of onchocercal reactive skin lesions was the most important risk factor for pruritus, with an odds ratio of 18.3 and 95% confidence interval of 15.19-22.04, which justifies the inclusion of regions with onchopercal skin disease in control programmes based on ivermectin distribution.
Abstract: An attempt was made to assess the true public-health importance of onchocercal skin disease throughout the African region and hence provide an objective basis for the rational planning of onchocerciasis control in the area. The seven collaborative centres that participated in the study (three in Nigeria and one each in Ghana, Cameroon, Tanzania and Uganda) were all in areas of rainforest or savannah-forest mosaic where onchocercal blindness is not common. A cross-sectional dermatological survey was undertaken at each site following a standard protocol. At each site, the aim was to examine at least 750 individuals aged 5 years and living in highly endemic communities and 220-250 individuals aged 5 years and living in a hypo-endemic (control) community. Overall, there were 5459 and 1451 subjects from hyper-and hypo-endemic communities, respectively. In the highly endemic communities, the prevalence of itching increased with age until 20 years and then plateaued, affecting 42% of the population aged 20 years. There was a strong correlation between the prevalence of itching and the level of endemicity (as measured by the prevalence of nodules; r=0.75; P<0.001). The results of a multivariate logistic regression analysis showed that, at the individual level, the presence of onchocercal reactive skin lesions (acute papular onchodermatitis, chronic papular onchodermatitis and/or lichenified onchodermatitis) was the most important risk factor for pruritus, with an odds ratio (OR) of 18.3 and 95% confidence interval (CI) of 15.19-22.04, followed by the presence of palpable onchocercal nodules (OR=4.63; CI=4.05-5.29). In contrast, non-onchocercal skin disease contributed very little to pruritus in the study communities (OR=1.29; CI=1.1-1.51). Onchocercal skin lesions affected 28% of the population in the endemic villages. The commonest type was chronic papular onchodermatitis (13%), followed by depigmentation (10%) and acute papular onchodermatitis (7%). The highest correlation with endemicity was seen for the prevalence of any onchocercal skin lesion and/or pruritus combined (r=0.8; P<0.001). Cutaneous onchocerciasis was found to be a common problem in many endemic areas in Africa which do not have high levels of onchocercal blindness. These findings, together with recent observations that onchocercal skin disease can have major, adverse, psycho-social and socio-economic effects, justify the inclusion of regions with onchocercal skin disease in control programmes based on ivermectin distribution. On the basis of these findings, the World Health Organization launched a control programme for onchocerciasis, the African Programme for Onchocerciasis Control (APOC), that covers 17 endemic countries in Africa.
105 citations
TL;DR: Where malaria and bancroftian filariasis are co-endemic and caused by parasites transmitted by the same species of mosquito, MDA should be augmented by interventions (use of bednets or house-spraying) against adult Anopheles.
Abstract: In certain filaria-mosquito combinations, the number of infective, third-stage larvae (L(3)) that develop in a mosquito is not proportional to the number of microfilariae (mff) ingested by that mosquito. As the number of mff ingested increases, the yield of L(3) per microfilaria may either increase (in a process known as 'facilitation') or decrease (in a process known as 'limitation'). Each ingested microfilaria that is successful (in terms of reaching the haemocoel) increases (facilitation) or decreases (limitation) the 'permeability' of the stomach wall for the next microfilaria. Limitation is seen in some culicine mosquitoes, especially the Aedes spp. that transmit Wuchereria bancrofti, which, in consequence, become relatively more efficient as vectors as they ingest fewer mff. This phenomenon makes the interruption of filarial transmission by Aedes spp. particularly difficult. As the survival of anopheline mosquitoes is adversely affected by filarial infection, the use of mass drug administrations (MDA) to reduce the prevalence and intensity of microfilaraemias may increase the mean lifespan of some of the local Anopheles species. If these same species also act as vectors of malarial parasites, effective, drug-based control of W. bancrofti may worsen the problem posed by malaria. Therefore, wherever malaria and bancroftian filariasis are co-endemic and caused by parasites transmitted by the same species of mosquito, MDA should be augmented by interventions (use of bednets or house-spraying) against adult Anopheles.
92 citations
TL;DR: The African Programme for Onchocerciasis Control (APOC) has made significant progress towards achieving its main objective: to establish sustainable community-directed treatment with ivermectin (CDTI) in onchoceria-endemic areas outside of the remit of the ONCHOCERCIasis Control Programme in West Africa (OCP) as mentioned in this paper.
Abstract: Since its inauguration in 1995, the African Programme for Onchocerciasis Control (APOC) has made significant progress towards achieving its main objective: to establish sustainable community-directed treatment with ivermectin (CDTI) in onchocerciasis-endemic areas outside of the remit of the Onchocerciasis Control Programme in West Africa (OCP). In the year 2000, the programme, in partnership with governments, non-governmental organizations and the endemic communities themselves, succeeded in treating 20,298,138 individuals in 49,654 communities in 63 projects in 14 countries. Besides the distribution of ivermectin, the programme has strengthened primary healthcare (PHC) through capacity-building, mobilization of resources and empowerment of communities. The community-directed-treatment approach is a model that can be adopted in developing other community-based health programmes. The approach has also made it possible to bring to the poor some measure of intervention in some other healthcare programmes, such as those for malaria control, eye care, maternal and child health, nutrition and immunization. CDTI presents, at all stages of its implementation, a unique window of opportunity for promoting the functional integration of healthcare activities. For this to be done successfully and in a co-ordinated manner, adequate funding of CDTI within PHC is as important as an effective sensitization of the relevant policy-makers, healthworkers and communities on the value of integration (accompanied by appropriate training at all levels). Evaluation of the experiences in integration of health services, particularly at community level, is crucial to the success of the integration.
89 citations
TL;DR: The main strategy of APOC, of community-directed treatment with ivermectin (CDTI), has enabled the programme to reach, empower and bring relief to remote and under-served, onchocerciasis-endemic communities.
Abstract: The main strategy of APOC, of community-directed treatment with ivermectin (CDTI), has enabled the programme to reach, empower and bring relief to remote and under-served, onchocerciasis-endemic communities. With CDTI, geographical and therapeutic coverages have increased substantially, in most areas, to the levels required to eliminate onchocerciasis as a public-health problem. Over 20 million people received treatment in 2000. APOC has also made effective use of the combination of the rapid epidemiological mapping of onchocerciasis (REMO) and geographical information systems (GIS), to provide information on the geographical distribution and prevalence of the disease. This has led to improvements in the identification of CDTI-priority areas, and in the estimates of the numbers of people to be treated. A unique public-private-sector partnership has been at the heart of APOC's relative success. Through efficient capacity-building, the programme's operations have positively influenced and strengthened the health services of participating countries. These laudable achievements notwithstanding, APOC faces many challenges during the second phase of its operations, when the full impact of the programme is expected to be felt. Notable among these challenges are the sustainability of CDTI, the strategy's effective integration into the healthcare system, and the full exploitation of its potential as an entry point for other health programmes. The channels created for CDTI, could, for example, help efforts to eliminate lymphatic filariasis (which will feature on the agenda of many participating countries during APOC's Phase 2). However, these other programmes need to be executed without compromising the onchocerciasis-control programme itself. Success in meeting these challenges will depend on the continued, wholehearted commitment of all the partners involved, particularly that of the governments of the participating countries.
87 citations
TL;DR: The epidemiology of chronic diarrhoea in adults with late-stage HIV infection was investigated in a prospective study in Bangkok, Thailand, and extensive genotypic heterogeneity was observed among the C. parvum human genotype and the 'bovine' genotype of C. Parvum in HIV-infected Thai patients.
Abstract: The epidemiology of chronic diarrhoea in adults with late-stage HIV infection was investigated in a prospective study in Bangkok, Thailand. During this investigation, 34 Cryptosporidium isolates were obtained from the faeces of 36 patients, with mean CD4(+) counts of only 14 x 10(6) CD4(+) cells/litre (range = 2 x 10(6) - 53 x 10(6)/litre), who had symptomatic cryptosporidiosis. Genotyping of these isolates, by RFLP analysis and DNA sequencing of the hypervariable region of the 18S rRNA gene, indicated that only 17 (50%) were of the C. parvum human genotype. The rest were of C. meleagridis (seven), the C. parvum 'bovine' genotype (five), C. felis (three) and C. canis (two). Extensive genotypic heterogeneity was observed among the C. parvum isolates, and two other isolates, one of C. meleagridis and the other of C. felis, produced atypical restriction patterns and were only identified by sequencing. This appears to represent the first report of C. canis and the 'bovine' genotype of C. parvum in HIV-infected Thai patients.
TL;DR: Infection in the livestock was age-dependent and, generally, the female animals were more often infected than the male, and the sequences were all found to be identical to that published for the common sheep strain of E. granulosus.
Abstract: The incidence of surgically confirmed cystic echinococcosis in eastern Libya was estimated to be at least 4.2 cases/100,000, with significantly more female cases than male. The prevalences of infection with Echinococcus granulosus among 1087 sheep, 881 goats, 428 camels and 614 cattle from the same region, determined postmortem in abattoirs, were 20%, 3.4%, 13.6% and 11%, respectively. Infection in the livestock was age-dependent and, generally, the female animals were more often infected than the male. The measurements of rostellar hooks on protoscoleces collected from sheep and cattle were similar but significantly different from the corresponding measurements of parasites of human or camel origin. However, when a portion of the cytochrome c-oxidase subunit I (cox1) gene from each of 30 protoscolex samples from Libya (12 from cattle, three from humans, five from camels and 10 from sheep) was sequenced, the sequences were all found to be identical to that published for the common sheep strain of E. granulosus.
TL;DR: This review identifies the most pertinent concerns that APOC must address, during Phase 2, to enhance the prospects of establishing sustainable systems for ivermectin distribution.
Abstract: The principal strategy adopted by the African Programme for Onchocerciasis Control (APOC), for the control of onchocerciasis in the 19 countries of Africa that now fall within the programme’s remit, is that of communitydirected treatment with ivermectin (CDTI). Halfway through its 12-year mandate, APOC has gathered enough information on the main challenges to guide its activities in Phase 2. An analysis of reports and other documents, emanating from consultants, scientists, monitors and national and project-level implementers, indicates that there are three broad categories of challenge: managerial; technical; and socio–political. Under these three categories, this review identifies the most pertinent concerns that APOC must address, during Phase 2, to enhance the prospects of establishing sustainable systems for ivermectin distribution. The major challenges include: (1) maintaining timely drug-collection mechanisms; (2) integrating CDTI with existing primary-healthcare services; (3) strengthening...
TL;DR: The aims of the present study were to check if local An.
Abstract: The aims of the present study in the south-west of the country were to check if local An. gambiae s.s. showed any resistance to pyrethroid insecticides and if so to compare the level of resistance observed with that reported in other countries in West Africa. (authors)
TL;DR: Despite the optimism of health-assessment reports prepared prior to the construction of the Diama dam, the unexpected appearance and spread of intestinal schistosomiasis as well as an increase in the incidence of urinary schistOSomiasis have aggravated public health in the Senegal River basin.
Abstract: The ecological changes caused by projects for the development of water resources are known to affect the epidemiology of water-related diseases. The effects of the construction of the Diama dam (completed in 1986) in the Senegal River on the epidemiology of malaria, urinary and intestinal schistosomiasis, diarrhoea and dysentery were investigated in four districts in northern Senegal. To make allowance for any general trend in reported morbidity (caused by changes in demography or the healthcare system), the numbers of cases of these illnesses reported by the basic healthcare facilities before and after the completion of the dam were compared with those of respiratory disease. Prior to the construction of the dam, malaria was the most encountered water-related disease in the medical records of all districts, followed by diarrhoea, dysentery and urinary schistosomiasis. This order remained the same after the completion of the dam. Despite the optimism of health-assessment reports prepared prior to the construction of the Diama dam, the unexpected appearance and spread of intestinal schistosomiasis as well as an increase in the incidence of urinary schistosomiasis have aggravated public health in the Senegal River basin. It remains to be judged whether the economic benefits of the dam will counterbalance its adverse effects.
TL;DR: There is clearly a need to improve communication strategies, to address the issues of absentees and refusals, to emphasise community ownership and to de-emphasise incentives for CDD in order to understand the determinants of project performance and to initiate any appropriate changes in the programme.
Abstract: Community-directed treatment is a relatively new strategy that was adopted in 1997 by the African Programme for Onchocerciasis Control (APOC), for large-scale distribution of ivermectin (Mectizan®). Participatory monitoring of 39 of the control projects based on community-directed treatment with ivermectin (CDTI) was undertaken from 1998–2000, with a focus on process implementation of the strategy and the predictors of sustainability. Data from 14,925 household interviews in 2314 villages, 183 complete treatment records, 382 focus-group discussions, and the results of interviews with 669 community leaders, 757 trained communitydirected drug distributors (CDD) and 146 health personnel (in 26 projects in four countries) were analysed. The data show that CDD dispensed ivermectin to 65.4% of the total population (71.2% of the eligible population), with no significant gender differences in coverage (P > 0.05). Treatment coverage ranged from 60.2% of the eligible subjects in Cameroon to 76.9% in Uganda....
TL;DR: It is indicated that AO is a viable alternative technique for the laboratory diagnosis of malaria in highly endemic countries and its promptness is an important advantage for the organization of health services and the provision of effective treatment of malaria cases.
Abstract: One hundred years ago, Giemsa's stain was employed for the first time for malaria diagnosis. Giemsa staining continues to be the method of choice in most malarious countries, although, in the recent past, several alternatives have been developed that exhibit some advantages. Considerable progress has been made with fluorescent dyes, particularly with Acridine Orange (AO). The literature on the discovery, development and validation of the AO method for malaria diagnosis is reviewed here. Compared with conventional Giemsa staining, AO shows a good diagnostic performance, with sensitivities of 81.3%-100% and specificities of 86.4%-100%. However, sensitivities decrease with lower parasite densities, and species differentiation may occasionally be difficult. The most notable advantage of the AO method over Giemsa staining is its promptness; results are readily available within 3-10 min, whereas Giemsa staining may take 45 min or even longer. This is an important advantage for the organization of health services and the provision of effective treatment of malaria cases. The national malaria control programme of Tanzania, together with the Japan International Co-operation Agency, began to introduce the AO method in Tanzania in 1994. So far, AO staining has been introduced in 70 regional and district hospitals, and 400 laboratory technicians have been trained to use the method. The results of this introduction, which are reviewed here and have several important implications, indicate that AO is a viable alternative technique for the laboratory diagnosis of malaria in highly endemic countries.
TL;DR: The first round of testing was designed to test the four most promising methods for DNA extraction from pools of mosquitoes and two of the four methods stood out as clearly the best and these will be now optimised and evaluated in two further rounds of testing.
Abstract: PCR has recently been studied as a promising tool for monitoring the progress of efforts to eliminate lymphatic filariasis. PCR can be used to test concurrently at least 30 pools, with as many as 40 mosquitoes in each pool, for the presence of filarial larvae. The SspI PCR assay for the detection of Wuchereria bancrofti DNA in pools of mosquitoes has been used since 1994 in a variety of laboratories worldwide. During that time, the original assay has been modified in these different laboratories and no standardized assay currently exists. In an effort to standardize and improve the assay, a meeting was held on 15-16 November 2001, at Emory University in Atlanta, with representatives from most of the laboratories currently using the assay. The first round of testing was designed to test the four most promising methods for DNA extraction from pools of mosquitoes. Two of the four methods stood out as clearly the best and these will be now optimised and evaluated in two further rounds of testing.
TL;DR: Spontaneous healing is commonly seen in Sudanese patients with PKDL, and persistence of the lesions is frequently associated with non-reactivity in the LST and high levels of anti-leishmanial antibodies.
Abstract: In an exploration of the natural history of post-kala-azar dermal leishmaniasis (PKDL), 134 residents of Sudan who had recently been diagnosed as cases of the disease were investigated. In each case, diagnosis had been based on clinical criteria, the temporal relationship between the rash and the treatment of visceral leishmaniasis (VL), positive results in direct agglutination tests (DAT) and/or leishmanin skin tests (LST), and the exclusion of other skin conditions. The mean (S.D.) age of the subjects was 6.4 (3.0) years. Although PKDL appeared commonest among those aged 4-8 years (P < 0.05), it was most severe in children aged
TL;DR: No clear relationship was observed between rainfall and malaria incidence, although a major development project to improve water resources in the study area may have masked any significant association.
Abstract: Some recent outbreaks of Plasmodium falciparum malaria have been attributed, at least in part, to increases in the intensity and duration of rainfall caused by the El Nino southern oscillation (ENSO), a periodic climatic phenomenon. Since it takes time for unusually heavy rainfall to translate into unusually high densities of the vector mosquitoes, it has been suggested that data on recent rainfall might be used to predict climate-related epidemics of malaria. This possibility was explored by comparing the patterns in the incidence of malaria in (1) Dungaria, a highly malarious village in the central-Indian district of Mandla, and (2) Mandla district as a whole, for the periods 1986-2000 and 1967-2000, respectively, with data on rainfall for the same areas and periods. Unfortunately, no clear relationship was observed between rainfall and malaria incidence, although a major development project to improve water resources in the study area (which resulted in local villages being partially or completely submerged in water) may have masked any significant association. A useful method for predicting which years are going to be high- or low-risk years for malaria epidemics, in the present and other epidemiological settings, remains a future goal.
TL;DR: An entomological study was carried out in coastal Lagos, south-western Nigeria, to explore the role of Anopheles gambiae s.s. and An.
Abstract: An entomological study was carried out in coastal Lagos, south-western Nigeria, to explore the role of Anopheles gambiae s.l. and An. moucheti in the transmission of Plasmodium falciparum in this holo-endemic area. Mosquitoes were caught, on human bait at night and by pyrethrum-spray catches during the day, twice a month throughout 2000.Of the 1812 Anopheles mosquitoes collected, An. gambiae s.l., the predominant vector species, represented 78.7% while the other 21.3% were An. moucheti. The results of a PCR-based test identified 56.8% of the mosquitoes of the An. gambiae complex collected as An. gambiae s.s. , 36.9% as An. melas and 6.3% as An. arabiensis. Anopheles gambiae s.s. was predominantly recorded in the wet season, biting females being collected from May to October, with a peak in July. Anopheles melas and An. moucheti were present throughout the yearlong study whereas An. arabiensis was mainly found in the dry season.The results of ELISA-based analyses of bloodmeals indicated that An. ga...
TL;DR: A small but significant negative relationship between intestinal helminthic infections and children's growth was detected in an urban environment with low prevalences of both intestinal parasitic infection and malnutrition.
Abstract: The prevalences of intestinal parasitic infections were investigated, between 1995 and 1996, in a household-based sample of 1044 children aged <5 years who lived in the city of Sao Paulo, Brazil. Only 10.7% of the children were infected, the most prevalent parasites being Giardia duodenalis (5.5%), Ascaris lumbricoides (4.4%) and Trichuris trichiura (1.0%). A comparison between these data and results from two previous population-based surveys, completed in Sao Paulo in 1974 and 1985, revealed a dramatic decrease in the prevalence of intestinal helminths in this age-group, with less marked changes in the prevalence of Giardia, over the two past decades. Despite the low prevalence of malnutrition (2.4% of stunting and 0.6% of wasting) and intestinal parasites in this population, there was a significant association (P=0.05, after controlling for potential confounding variables) between helminth (but not Giardia) infection and height. The helminth-infected children had a mean height-for-age z-score of...
TL;DR: PCR-based techniques targeting the HhaI repeat can therefore be employed for monitoring B. timori in the framework of the Global Programme to Eliminate Lymphatic Filariasis.
Abstract: Brugia timori is widely distributed on Alor Island, Indonesia, where it causes a high degree of morbidity. The HhaI tandem repeat of B. timori was found to be identical to that of B. malayi, for which sensitive PCR-based assays have already been developed. Using one of these assays, a single microfilaria (mf) of B. timori, present in a spot of dry blood on filter paper, could be detected. The assay was equally sensitive in the detection of B. timori and B. malayi. When the collected mosquitoes were pooled according to species and tested with the assay, 39 (64%) of the 61 Anopheles barbirostris pools (containing a total of 642 mosquitoes) were positive. As none of the 33 Culex pools tested (which contained 624 mosquitoes) gave a positive result, and An. barbirostris is the only Anopheles species commonly caught on human bait in Alor, An. barbirostris is assumed to be the main and perhaps only local vector. Brugia timori could be differentiated from B. malayi by restriction-endonuclease digestion of the PCR-amplified mitochondrial cytochrome oxidase subunit 2. A few distinct nucleotide exchanges were also found in the second internal transcribed ribosomal spacer of the filariae, and in the 16S rDNA and FTSZ gene of their Wolbachia endobacteria. The results show that B. timori can be effectively detected using the PCR-based assay developed for B. malayi and can then be differentiated from B. malayi by other molecular markers. PCR-based techniques targeting the HhaI repeat can therefore be employed for monitoring B. timori in the framework of the Global Programme to Eliminate Lymphatic Filariasis.
TL;DR: Evidence of a remodelling process, in which the lymphatic endothelial cells appear to have a key role, is provided for the first time in bancroftian filariasis.
Abstract: Although morphology is generally limited to static images, the histopathological features of bancroftian lymphatic disease are presented here in a way that is as dynamic as possible and closely associated with the clinical, ultrasonographic and surgical characteristics. The protean spectrum of alterations seen in the host's lymphatic vessels is discussed, and the changes caused by the live and dead worms are highlighted, as independent events. Evidence of a remodelling process, in which the lymphatic endothelial cells appear to have a key role, is provided for the first time. Despite many new pieces of information, there remain many 'blank pages' in the natural history of bancroftian filariasis.
TL;DR: A modest reduction in the numbers of mosquitoes biting humans attributable to the use of the insecticide-treated nets strongly suppressed the risk of W. bancrofti transmission.
Abstract: Nocturnally periodic bancroftian filariasis is maintained by three mainly endophilic vectors in East Africa: Culex quinquefasciatus, Anopheles funestus and the An. gambiae complex. Permethrin-impregnated bednets provide considerable protection against these mosquitoes, but the species respond differently. The degree of protection conferred by treated bednets was determined in Kenyan communities where all three vectors actively transmit Wuchereria bancrofti. The annual transmission potential in the communities (i.e. an estimate of the number of human infective, third-stage larvae of W. bancrofti inoculated into each villager each year) was reduced by 92%, through the nets' impact on vector biting rates (reduced by 22%) and their cumulative impact on the annual infective biting rate (reduced by 95%). Thus a modest reduction in the numbers of mosquitoes biting humans, attributable to the use of the insecticide-treated nets, strongly suppressed the risk of W. bancrofti transmission.
TL;DR: A new Leishmania tropica zymodeme—causative agent of canine visceral leishmaniasis in northern Morocco is identified.
Abstract: (2002). A new Leishmania tropica zymodeme—causative agent of canine visceral leishmaniasis in northern Morocco. Annals of Tropical Medicine & Parasitology: Vol. 96, No. 6, pp. 637-638.
TL;DR: NSI are common, preventable sources of infection and stress for HCW in Africa and during 3 years of training as a clinician more than six in 1000 individuals would be infected with HIV as a result of NSI and almost 10 in 1000 would beinfected with hepatitis B virus by the same route.
Abstract: The on-going HIV epidemic has generally increased fear of needle-stick injuries (NSI) and renewed interest in the problem such injuries pose in Africa. The aims of the present study were to evaluate the frequency of NSI, explore the circumstances surrounding each injury and estimate the corresponding infection risk, among healthcare workers (HCW) in Uganda. Questionnaires, asking the recipients how many NSI they had suffered in the past year, how each of these NSI had occurred, what (perceived) risk of infection was associated with each injury, and what their practical and psychological reactions were, were sent to the HCW associated with the Mbarara Teaching Hospital in Uganda. Of the 280 individuals who received questionnaires, 180 (64%) responded and 100 (55% of the respondents) each reported suffering at least one NSI in the previous year. The total number of NSI reported (336) represented an incidence of 1.86 NSI/HCW-year. Interns suffered more NSI (annual mean=4.8) than any other occupational group. Most NSI occurred when patients moved during procedures, when HCW re-sheathed needles, or during suturing (each reported by 55 HCW--30% of those responding). Following NSI, 60 HCW said they squeezed the site of the injury and washed it with bleach, 43 believed they had a 10% risk of HIV infection, 87 felt anxious, 54 felt depressed, 40 prayed, 24 had an HIV test, and four were counselled. To estimate actual infection risk, 435 patients were screened for antibody to HIV (1 and 2) and for the surface antigen of the hepatitis B virus (HBSAg); 26% and 2.8% were found seropositive, respectively. These seroprevalences were multiplied by previously determined probabilities of transmission to give estimated risks of infection (following a single NSI) of 0.08% for HIV and 0.135% for hepatitis B. During 3 years of training as a clinician (i.e. 2 years as a medical student and 1 year as an intern), more than six in 1000 individuals would be infected with HIV as a result of NSI and almost 10 in 1000 would be infected with hepatitis B virus by the same route. NSI are common, preventable sources of infection and stress for HCW in Africa.
TL;DR: This is the first panel of polymorphic microsatellite markers, to be isolated de novo from any species of Leishmania, that is large enough for population-biology applications.
Abstract: The investigation of microsatellite markers has recently superseded that of isoenzymes for many population-biology applications. Microsatellites have the advantages of being dominant, neutral, highly polymorphic and easily scored by high-throughput methods. However, it is necessary to develop a new panel of markers for each group of organisms of interest. Previously, only about 5% of the markers that amplify Leishmania major microsatellite loci were also found to amplify L. donovani loci. A panel of 20 microsatellite markers that are polymorphic in L. donovani and L. infantum has now been developed, using a rapid-enrichment method that will be suitable for developing libraries of markers for other trypanosomatid species. This is the first panel of polymorphic microsatellite markers, to be isolated de novo from any species of Leishmania, that is large enough for population-biology applications.
TL;DR: The main risk factors found to be significantly associated with CE were having a family member with the disease, spending the first years of life surrounded by a large number of dogs, and having a father who slaughtered sheep at his workplace.
Abstract: In 1984 the prevalence of cystic echinococcosis (CE) in Rio Negro province in central Argentina reached alarming levels, with almost 6% of children aged 7-13 years infected with the causative agent, Echinococcus granulosus . Although the control activities developed between 1980-2000 have now lowered the prevalence of infection in this age-group to 1.1%, transmission of E. granulosus has clearly not ceased. The aim of the present study was to identify possible flaws in the control programme and the risk factors associated with CE. The 24 cases and 66 controls used were identified during a survey of the 1070 schoolchildren attending 12 schools in Ingeniero Jacobacci, Rio Negro province. In interviews based around a standardized questionnaire, the adult female with responsibility for each subject (usually the mother but sometimes a grandmother or guardian) was asked 70 questions about the child and his or her immediate family, their contact with dogs and relevant environmentmental factors, and their...