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1.
Pathogens ; 10(3)2021 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-33799921

RESUMEN

Malnutrition and intestinal parasites continue to have serious impacts on growth and cognitive development of children in Angola. A longitudinal four-arm randomized parallel trial was conducted to investigate if deworming with a single annual dose of albendazole (annual-ALB) or a four-monthly test-and-treat (4TT) intestinal parasites approach at individual or household levels improve nutritional outcomes of pre-school children in Bengo province. Children with intestinal parasites (n = 121) were randomly assigned (1:1:1:1) to arm A1: annual-ALB*individual level; A2: annual-ALB*household level; A3: 4TT*individual; and A4: 4TT*household level. At baseline, 4, 8, 12, 16, 20, and 24 months of follow-up, growth was assessed by height, weight, height-for-age, weight-for-height, weight-for-age, and mid-upper arm circumference. Intention-to-treat analysis was done using non-parametric approach, mixed effect models, and generalized estimating equations (GEE). Initially, 57% and 26% of the children were infected by Giardia lamblia and Ascaris lumbricoides, respectively. This study did not show that a 4TT intestinal parasites approach results on better growth outcomes of children (height, weight, HAZ, WAZ, WHZ and MUACZ) when compared with annual ALB, with exception of height and WHZ using GEE model at 5% level. Positive temporal effects on most nutrition outcomes were observed. Implementing a longitudinal study in a poor setting is challenging and larger sample sizes and 'pure and clean' data are difficult to obtain. Nevertheless, learned lessons from this intensive study may contribute to future scientific research and to tailor multidisciplinary approaches to minimize malnutrition and infections in resource-poor countries.

2.
PLoS Negl Trop Dis ; 14(6): e0008277, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32569275

RESUMEN

BACKGROUND: Better knowledge of the efficacy and safety of single-dose 40 mg/kg oral praziquantel in preschool-age children is required, should preventive chemotherapy programs for schistosomiasis be expanded to include this age group. METHODOLOGY: We analyzed individual participant-level data from 16 studies (13 single-arm or cohort studies and three randomized trials), amounting to 683 preschool-age children (aged <6 years) and 2,010 school-age children (aged 6-14 years). Children had a documented Schistosoma mansoni or S. haematobium infection, were treated with single 40 mg/kg oral praziquantel, and assessed between 21 and 60 days post-treatment. Efficacy was expressed as arithmetic mean and individual egg reduction rate (ERR) and meta-analyzed using general linear models and mixed models. Safety was summarized using reported adverse events (AEs). PRINCIPAL FINDINGS: Preschool-age children had significantly lower baseline Schistosoma egg counts and more losses to follow-up compared to school-age children. No difference in efficacy was found between preschool- and school-age children using a general linear model of individual-participant ERR with baseline log-transformed egg count as covariate and study, age, and sex as fixed variables, and a mixed model with a random effect on the study. Safety was reported in only four studies (n = 1,128 individuals); few AEs were reported in preschool-age children 4 and 24 hours post-treatment as well as at follow-up. Three severe but not serious AEs were recorded in school-age children during follow-up. CONCLUSIONS/SIGNIFICANCE: There is no indication that single-dose 40 mg/kg oral praziquantel would be less efficacious and less safe in preschool-age children compared to school-age children, with the caveat that only few randomized comparisons exist between the two age groups. Preventive chemotherapy might therefore be extended to preschool-age children, with proper monitoring of its efficacy and safety.


Asunto(s)
Antihelmínticos/administración & dosificación , Quimioprevención/métodos , Praziquantel/administración & dosificación , Esquistosomiasis Urinaria/prevención & control , Esquistosomiasis mansoni/prevención & control , Administración Oral , Adolescente , Animales , Antihelmínticos/efectos adversos , Niño , Preescolar , Heces/parasitología , Femenino , Humanos , Modelos Lineales , Masculino , Recuento de Huevos de Parásitos , Praziquantel/efectos adversos , Ensayos Clínicos Controlados Aleatorios como Asunto , Schistosoma haematobium , Schistosoma mansoni , Esquistosomiasis Urinaria/tratamiento farmacológico , Esquistosomiasis mansoni/tratamiento farmacológico , Resultado del Tratamiento
3.
Parasit Vectors ; 10(1): 460, 2017 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-29017583

RESUMEN

BACKGROUND: This study was designed to determine the distribution and identity of potential intermediate snail hosts of Schistosoma spp. in Bengo, Luanda, Kwanza Norte and Malanje Provinces in north-western Angola. This is an area where infection with Schistosoma haematobium, causing urogenital schistosomiasis, is common but little is yet known about transmission of the disease. Angola has had a varied past with regard to disease control and is revitalising efforts to combat neglected tropical diseases. METHODS: Snails were sampled from 60 water-contact points. Specimens of the genera Bulinus, Biomphalaria or Lymnaea were screened for trematode infections by inducing cercarial shedding. Snails were initially identified using shell morphology; subsequently a cytochrome c oxidase subunit 1 (cox1) gene fragment was amplified from a subset of snails from each site, for molecular identification. Cercariae were captured onto FTA cards for molecular analysis. Specimens of Bulinus angolensis collected from the original locality of the type specimen have been characterised and comparisons made with snails collected in 1957 held at the Natural History Museum, London, UK. RESULTS: In total snails of nine genera were identified using morphological characteristics: Biomphalaria, Bulinus, Gyraulus, Lanistes, Lentorbis, Lymnaea, Melanoides, Physa and Succinea. Significant for schistosomiasis transmission, was the discovery of Bulinus globosus, B. canescens, B. angolensis, B. crystallinus and Biomphalaria salinarum in their type-localities and elsewhere. Bulinus globosus and B. angolensis occurred in two distinct geographical areas. The cox1 sequence for B. globosus differed markedly from those from specimens of this species collected from other countries. Bulinus angolensis is more closely related to B. globosus than originally documented and should be included in the B. africanus group. Schistosoma haematobium cercariae were recovered from B. globosus from two locations: Cabungo, Bengo (20 snails) and Calandula, Malanje (5 snails). Schistosoma haematobium cercariae were identified as group 1 cox1 corresponding to the type common throughout the African mainland. CONCLUSIONS: Various freshwater bodies in north-western Angola harbour potential intermediate snail hosts for urogenital schistosomiasis, highlighting the need to map the rest of the country to identify areas where transmission can occur and where control efforts should be targeted. The molecular phylogeny generated from the samples confirmed that considerable variation exists in B. globosus, which is the primary snail host for S. haematobium in many regions of Africa.


Asunto(s)
Distribución Animal , Bulinus/clasificación , Caracoles/clasificación , Angola , Animales , Bulinus/genética , Bulinus/parasitología , Bulinus/fisiología , Cercarias , Vectores de Enfermedades , Agua Dulce/parasitología , Enfermedades Desatendidas/epidemiología , Enfermedades Desatendidas/parasitología , Filogenia , Schistosoma haematobium/aislamiento & purificación , Schistosoma haematobium/fisiología , Esquistosomiasis Urinaria/parasitología , Esquistosomiasis Urinaria/transmisión , Caracoles/genética , Caracoles/parasitología
4.
Parasit Vectors ; 9: 41, 2016 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-26813154

RESUMEN

BACKGROUND: By 2020, the global health community aims to control and eliminate human helminthiases, including schistosomiasis in selected African countries, principally by preventive chemotherapy (PCT) through mass drug administration (MDA) of anthelminthics. Quantitative monitoring of anthelminthic responses is crucial for promptly detecting changes in efficacy, potentially indicative of emerging drug resistance. Statistical models offer a powerful means to delineate and compare efficacy among individuals, among groups of individuals and among populations. METHODS: We illustrate a variety of statistical frameworks that offer different levels of inference by analysing data from nine previous studies on egg counts collected from African children before and after administration of praziquantel. RESULTS: We quantify responses to praziquantel as egg reduction rates (ERRs), using different frameworks to estimate ERRs among population strata, as average responses, and within strata, as individual responses. We compare our model-based average ERRs to corresponding model-free estimates, using as reference the World Health Organization (WHO) 90% threshold of optimal efficacy. We estimate distributions of individual responses and summarize the variation among these responses as the fraction of ERRs falling below the WHO threshold. CONCLUSIONS: Generic models for evaluating responses to anthelminthics deepen our understanding of variation among populations, sub-populations and individuals. We discuss the future application of statistical modelling approaches for monitoring and evaluation of PCT programmes targeting human helminthiases in the context of the WHO 2020 control and elimination goals.


Asunto(s)
Antihelmínticos/farmacología , Helmintiasis/tratamiento farmacológico , Modelos Estadísticos , Praziquantel/farmacología , Schistosomatidae/efectos de los fármacos , Esquistosomiasis/tratamiento farmacológico , Adolescente , África/epidemiología , Animales , Niño , Preescolar , Resistencia a Medicamentos , Heces/parasitología , Femenino , Helmintiasis/epidemiología , Humanos , Masculino , Óvulo , Esquistosomiasis/epidemiología , Resultado del Tratamiento
5.
PLoS Negl Trop Dis ; 9(7): e0003831, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26196386

RESUMEN

BACKGROUND: Namibia is now ready to begin mass drug administration of praziquantel and albendazole against schistosomiasis and soil-transmitted helminths, respectively. Although historical data identifies areas of transmission of these neglected tropical diseases (NTDs), there is a need to update epidemiological data. For this reason, Namibia adopted a new protocol for mapping of schistosomiasis and geohelminths, formally integrating rapid diagnostic tests (RDTs) for infections and morbidity. In this article, we explain the protocol in detail, and introduce the concept of 'mapping resolution', as well as present results and treatment recommendations for northern Namibia. METHODS/FINDINGS/INTERPRETATION: This new protocol allowed a large sample to be surveyed (N = 17,896 children from 299 schools) at relatively low cost (7 USD per person mapped) and very quickly (28 working days). All children were analysed by RDTs, but only a sub-sample was also diagnosed by light microscopy. Overall prevalence of schistosomiasis in the surveyed areas was 9.0%, highly associated with poorer access to potable water (OR = 1.5, P<0.001) and defective (OR = 1.2, P<0.001) or absent sanitation infrastructure (OR = 2.0, P<0.001). Overall prevalence of geohelminths, more particularly hookworm infection, was 12.2%, highly associated with presence of faecal occult blood (OR = 1.9, P<0.001). Prevalence maps were produced and hot spots identified to better guide the national programme in drug administration, as well as targeted improvements in water, sanitation and hygiene. The RDTs employed (circulating cathodic antigen and microhaematuria for Schistosoma mansoni and S. haematobium, respectively) performed well, with sensitivities above 80% and specificities above 95%. CONCLUSION/SIGNIFICANCE: This protocol is cost-effective and sensitive to budget limitations and the potential economic and logistical strains placed on the national Ministries of Health. Here we present a high resolution map of disease prevalence levels, and treatment regimens are recommended.


Asunto(s)
Pruebas Diagnósticas de Rutina/métodos , Schistosoma/aislamiento & purificación , Esquistosomiasis/diagnóstico , Esquistosomiasis/epidemiología , Suelo/parasitología , Adolescente , Animales , Niño , Estudios de Cohortes , Pruebas Diagnósticas de Rutina/economía , Heces/parasitología , Femenino , Humanos , Masculino , Namibia/epidemiología , Schistosoma/fisiología , Esquistosomiasis/parasitología , Esquistosomiasis/transmisión , Adulto Joven
6.
PLoS Negl Trop Dis ; 9(6): e0003821, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26086551

RESUMEN

BACKGROUND: The control of schistosomiasis emphasizes preventive chemotherapy with praziquantel, which aims at decreasing infection intensity and thus morbidity in individuals, as well as transmission in communities. Standardizing methods to assess treatment efficacy is important to compare trial outcomes across settings, and to monitor program effectiveness consistently. We compared customary methods and looked at possible complementary approaches in order to derive suggestions for standardizing outcome measures. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed data from 24 studies conducted at African, Asian, and Latin American sites, enrolling overall 4,740 individuals infected with Schistosoma mansoni, S. haematobium, or S. japonicum, and treated with praziquantel at doses of 40-80 mg/kg. We found that group-based arithmetic and geometric means can be used interchangeably to express egg reduction rates (ERR) only if treatment efficacy is high (>95%). For lower levels of efficacy, ERR estimates are higher with geometric than arithmetic means. Using the distribution of individual responses in egg excretion, 6.3%, 1.7% and 4.3% of the subjects treated for S. haematobium, S. japonicum and S. mansoni infection, respectively, had no reduction in their egg counts (ERR = 0). The 5th, 10th, and 25th centiles of the subjects treated for S. haematobium had individual ERRs of 0%, 49.3%, and 96.5%; the corresponding values for S. japonicum were 75%, 99%, and 99%; and for S. mansoni 18.2%, 65.3%, and 99.8%. Using a single rather than quadruplicate Kato-Katz thick smear excluded 19% of S. mansoni-infected individuals. Whilst the effect on estimating ERR was negligible by individual studies, ERR estimates by arithmetic means were 8% lower with a single measurement. CONCLUSIONS/SIGNIFICANCE: Arithmetic mean calculations of Schistosoma ERR are more sensitive and therefore more appropriate to monitor drug performance than geometric means. However, neither are satisfactory to identify poor responders. Group-based response estimated by arithmetic mean and the distribution of individual ERRs are correlated, but the latter appears to be more apt to detect the presence and to quantitate the magnitude of suboptimal responses to praziquantel.


Asunto(s)
Evaluación de Resultado en la Atención de Salud/métodos , Óvulo/efectos de los fármacos , Praziquantel/farmacología , Schistosoma/efectos de los fármacos , Esquistosomiasis/epidemiología , Esquistosomiasis/prevención & control , Animales , Interpretación Estadística de Datos , Heces/parasitología , Modelos Lineales
7.
Parasitology ; 141(14): 1826-40, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24725546

RESUMEN

It is generally recommended to perform multiple stool examinations in order to improve the diagnostic accuracy when assessing the impact of mass drug administration programmes to control human intestinal worm infections and determining efficacy of the drugs administered. However, the collection and diagnostic work-up of multiple stool samples increases costs and workload. It has been hypothesized that these increased efforts provide more accurate results when infection and drug efficacy are summarized by prevalence (proportion of subjects infected) and cure rate (CR, proportion of infected subjects that become egg-negative after drug administration), respectively, but not when these indicators are expressed in terms of infection intensity and egg reduction rate (ERR). We performed a meta-analysis of six drug efficacy trials and one epidemiological survey. We compared prevalence and intensity of infection, CR and ERR based on collection of one or two stool samples that were processed with single or duplicate Kato-Katz thick smears. We found that the accuracy of prevalence estimates and CR was lowest with the minimal sampling effort, but that this was not the case for estimating infection intensity and ERR. Hence, a single Kato-Katz thick smear is sufficient for reporting infection intensity and ERR following drug treatment.


Asunto(s)
Helmintiasis/diagnóstico , Helmintos/aislamiento & purificación , Parasitosis Intestinales/diagnóstico , Schistosoma/aislamiento & purificación , Esquistosomiasis/diagnóstico , Manejo de Especímenes/métodos , Animales , Heces/parasitología , Helmintiasis/tratamiento farmacológico , Helmintiasis/parasitología , Humanos , Parasitosis Intestinales/tratamiento farmacológico , Parasitosis Intestinales/parasitología , Masculino , Recuento de Huevos de Parásitos/economía , Recuento de Huevos de Parásitos/métodos , Prevalencia , Esquistosomiasis/tratamiento farmacológico , Esquistosomiasis/parasitología , Suelo/parasitología , Encuestas y Cuestionarios , Resultado del Tratamiento
8.
Lancet Infect Dis ; 14(7): 640-9, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24747019

RESUMEN

HIV/AIDS and schistosomiasis both cause a substantial disease burden in sub-Saharan Africa and the two diseases often overlap in their epidemiological characteristics. Although disease-specific control interventions are continuing, potential synergies in the control efforts for these two diseases have not been investigated. With a focus on children with schistosomiasis, we assess the risk for increased HIV transmission, HIV progression, and impaired response to drugs when given alongside HIV interventions. A new research agenda tailored to children is needed to better understand the interactions of these two diseases and the potential for combined responses.


Asunto(s)
Coinfección/parasitología , Coinfección/virología , Infecciones por VIH/parasitología , Esquistosomiasis/virología , África/epidemiología , Niño , Coinfección/epidemiología , Coinfección/prevención & control , Infecciones por VIH/epidemiología , Infecciones por VIH/prevención & control , Humanos , Factores de Riesgo , Esquistosomiasis/epidemiología , Esquistosomiasis/parasitología , Esquistosomiasis/prevención & control
10.
Geospat Health ; 7(2): 341-54, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23733295

RESUMEN

Anaemia is known to have an impact on child development and mortality and is a severe public health problem in most countries in sub-Saharan Africa. We investigated the consistency between ecological and individual-level approaches to anaemia mapping by building spatial anaemia models for children aged ≤15 years using different modelling approaches. We aimed to (i) quantify the role of malnutrition, malaria, Schistosoma haematobium and soil-transmitted helminths (STHs) in anaemia endemicity; and (ii) develop a high resolution predictive risk map of anaemia for the municipality of Dande in northern Angola. We used parasitological survey data for children aged ≤15 years to build Bayesian geostatistical models of malaria (PfPR≤15), S. haematobium, Ascaris lumbricoides and Trichuris trichiura and predict small-scale spatial variations in these infections. Malnutrition, PfPR≤15, and S. haematobium infections were significantly associated with anaemia risk. An estimated 12.5%, 15.6% and 9.8% of anaemia cases could be averted by treating malnutrition, malaria and S. haematobium, respectively. Spatial clusters of high risk of anaemia (>86%) were identified. Using an individual-level approach to anaemia mapping at a small spatial scale, we found that anaemia in children aged ≤15 years is highly heterogeneous and that malnutrition and parasitic infections are important contributors to the spatial variation in anaemia risk. The results presented in this study can help inform the integration of the current provincial malaria control programme with ancillary micronutrient supplementation and control of neglected tropical diseases such as urogenital schistosomiasis and STH infections.


Asunto(s)
Anemia/epidemiología , Helmintiasis/epidemiología , Malaria/epidemiología , Desnutrición/epidemiología , Adolescente , Angola/epidemiología , Niño , Preescolar , Estudios Transversales , Femenino , Helmintiasis/sangre , Humanos , Lactante , Recién Nacido , Masculino , Desnutrición/sangre , Madres , Prevalencia , Factores de Riesgo , Análisis Espacial
11.
PLoS Negl Trop Dis ; 7(1): e2008, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23359826

RESUMEN

BACKGROUND: The World Health Organization now recommends the provision of praziquantel treatment to preschool-aged children infected with schistosomiasis. For intestinal schistosomiasis the current operational field diagnostic standard is examination of a thick Kato-Katz smear by microscopy prepared from a single stool specimen, and although pragmatic, this methodology has well-known shortcomings. Here, as a potential alternative, the performance of the urine circulating cathodic antigen (CCA) dipstick test was assessed in terms of disease-mapping and point-of-care diagnosis for intestinal schistosomiasis in preschool-aged children. Our manuscript reports on findings at baseline and at the end of a one-year longitudinal treatment study. METHODOLOGY/PRINCIPAL FINDINGS: A total of 925 children (mean age 2.8 years) were initially recruited from six lakeshore villages representative of high, moderate and low levels of disease transmission. At baseline, all children were tested for intestinal schistosomiasis by microscopic examination of duplicate Kato-Katz smears prepared from a single stool faecal, by antigen detection with the urine CCA dipstick test and by serology with a commercially available ELISA test (as 'gold-standard') that measures host antibody titres to soluble egg antigens. As a point-of-care diagnosis, the urine CCA dipstick test achieved sensitivity and specificity values ranging from 52.5-63.2% and 57.7-75.6%, respectively, with faecal microscopy achieving very high specificities (>87%) but sensitivities as low as 16.7% in the low transmission setting. CONCLUSION/SIGNIFICANCE: The urine CCA test was shown to be more effective than faecal microscopy especially in lower transmission settings. The diagnostic performance of this test was not significantly impacted by treatment history or co-infections with other intestinal helminths.


Asunto(s)
Antígenos Helmínticos/orina , Técnicas de Laboratorio Clínico/métodos , Glicoproteínas/orina , Proteínas del Helminto/orina , Parasitología/métodos , Sistemas de Atención de Punto , Esquistosomiasis mansoni/diagnóstico , Anticuerpos Antihelmínticos/sangre , Niño , Preescolar , Ensayo de Inmunoadsorción Enzimática , Heces/parasitología , Femenino , Humanos , Inmunoensayo/métodos , Lactante , Masculino , Microscopía , Sensibilidad y Especificidad
12.
Malar J ; 11: 385, 2012 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-23173636

RESUMEN

BACKGROUND: Identifying and targeting hyper-endemic communities within meso-endemic areas constitutes an important challenge in malaria control in endemic countries such like Angola. Recent national and global predictive maps of malaria allow the identification and quantification of the population at risk of malaria infection in Angola, but their small-scale accuracy is surrounded by large uncertainties. To observe the need to develop higher resolution malaria endemicity maps a predictive risk map of malaria infection for the municipality of Dande (a malaria endemic area in Northern Angola) was developed and compared to existing national and global maps, the role of individual, household and environmental risk factors for malaria endemicity was quantified and the spatial variation in the number of children at-risk of malaria was estimated. METHODS: Bayesian geostatistical models were developed to predict small-scale spatial variation using data collected during a parasitological survey conducted from May to August 2010. Maps of the posterior distributions of predicted prevalence were constructed in a geographical information system. RESULTS: Malaria infection was significantly associated with maternal malaria awareness, households with canvas roofing, distance to health care centre and distance to rivers. The predictive map showed remarkable spatial heterogeneity in malaria risk across the Dande municipality in contrast to previous national and global spatial risk models; large high-risk areas of malaria infection (prevalence >50%) were found in the northern and most eastern areas of the municipality, in line with the observed prevalence. CONCLUSIONS: There is remarkable spatial heterogeneity of malaria burden which previous national and global spatial modelling studies failed to identify suggesting that the identification of malaria hot-spots within seemingly mesoendemic areas may require the generation of high resolution malaria maps. Individual, household and hydrological factors play an important role in the small-scale geographical variation of malaria risk in northern Angola. The results presented in this study can be used by provincial malaria control programme managers to help target the delivery of malaria control resources to priority areas in the Dande municipality.


Asunto(s)
Enfermedades Endémicas , Malaria/epidemiología , Topografía Médica , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Angola/epidemiología , Niño , Preescolar , Estudios Transversales , Estudios Epidemiológicos , Composición Familiar , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Prevalencia , Medición de Riesgo , Adulto Joven
13.
Am J Trop Med Hyg ; 87(4): 694-700, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22927499

RESUMEN

There is a need for field-applicable markers to assess morbidity associated with intestinal schistosomiasis, especially in the context of preventive chemotherapy in young children. We investigated whether fecal occult blood (FOB) point-of-care tests could be used to assess intestinal pathology over a 12-month period in a cohort of 382 children (< 5 years of age). We found a strong association between egg-patent schistosomiasis and FOB at baseline (odds ratio [OR] = 3.1, P < 0.0001), 6 months (OR = 3.4, P < 0.0001), and 12 months (OR = 3.5, P < 0.0001), despite repeated chemotherapy. There were tendencies for prevalence of FOB to decrease in children who became egg negative and increase in those who became egg positive. Our results demonstrate overt disease in children less than five years of age. We therefore propose that FOB is useful for assessing dynamics of intestinal morbidity in young children at the community level and monitoring changes in morbidity after mass chemotherapy.


Asunto(s)
Antihelmínticos/uso terapéutico , Sangre Oculta , Praziquantel/uso terapéutico , Schistosoma mansoni/efectos de los fármacos , Esquistosomiasis mansoni/epidemiología , Esquistosomiasis mansoni/prevención & control , Animales , Preescolar , Heces/parasitología , Femenino , Humanos , Lactante , Masculino , Morbilidad , Recuento de Huevos de Parásitos , Sistemas de Atención de Punto , Prevalencia , Schistosoma mansoni/crecimiento & desarrollo , Schistosoma mansoni/aislamiento & purificación , Esquistosomiasis mansoni/parasitología , Esquistosomiasis mansoni/patología , Uganda/epidemiología
14.
Antimicrob Agents Chemother ; 56(10): 5271-7, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22850519

RESUMEN

Artemisinin-based combination therapy for malaria has become widely available across Africa. Populations of Plasmodium falciparum that were previously dominated by chloroquine (CQ)-resistant genotypes are now under different drug selection pressures. P. malariae, P. ovale curtisi, and P. ovale wallikeri are sympatric with P. falciparum across the continent and are frequently present as coinfections. The prevalence of human Plasmodium species was determined by PCR using DNA from blood spots collected during a cross-sectional survey in northern Angola. P. falciparum was genotyped at resistance-associated loci in pfcrt and pfmdr1 by real-time PCR or by direct sequencing of amplicons. Of the 3,316 samples collected, 541 (16.3%) contained Plasmodium species infections; 477 (88.2%) of these were P. falciparum alone, 6.5% were P. falciparum and P. malariae together, and 1.1% were P. vivax alone. The majority of the remainder (3.7%) harbored P. ovale curtisi or P. ovale wallikeri alone or in combination with other species. Of 430 P. falciparum isolates genotyped for pfcrt, 61.6% carried the wild-type allele CVMNK at codons 72 to 76, either alone or in combination with the resistant allele CVIET. No other pfcrt allele was found. Wild-type alleles dominated at codons 86, 184, 1034, 1042, and 1246 of the pfmdr1 locus among the sequenced isolates. In contrast to previous studies, P. falciparum in the study area comprises an approximately equal mix of genotypes associated with CQ sensitivity and with CQ resistance, suggesting either lower drug pressure due to poor access to treatment in rural areas or a rapid impact of the policy change away from the use of standard monotherapies.


Asunto(s)
Plasmodium falciparum/genética , Plasmodium vivax/genética , Proteínas Protozoarias/genética , África , Angola , Antimaláricos/uso terapéutico , Cloroquina/uso terapéutico , Genotipo , Humanos , Malaria Falciparum/tratamiento farmacológico , Malaria Falciparum/parasitología , Plasmodium falciparum/efectos de los fármacos , Plasmodium falciparum/patogenicidad , Plasmodium vivax/efectos de los fármacos , Plasmodium vivax/patogenicidad
15.
PLoS One ; 7(4): e33189, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22493664

RESUMEN

BACKGROUND: Malaria, schistosomiasis and geohelminth infection are linked to maternal and child morbidity and mortality in sub-Saharan Africa. Knowing the prevalence levels of these infections is vital to guide governments towards the implementation of successful and cost-effective disease control initiatives. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional study of 1,237 preschool children (0-5 year olds), 1,142 school-aged children (6-15 year olds) and 960 women (>15 year olds) was conducted to understand the distribution of malnutrition, anemia, malaria, schistosomiasis (intestinal and urinary) and geohelminths in a north-western province of Angola. We used a recent demographic surveillance system (DSS) database to select and recruit suitable households. Malnutrition was common among children (23.3% under-weight, 9.9% wasting and 32.2% stunting), and anemia was found to be a severe public health problem (i.e., >40%). Malaria prevalence was highest among preschool children reaching 20.2%. Micro-hematuria prevalence levels reached 10.0% of preschool children, 16.6% of school-aged children and 21.7% of mothers. Geohelminth infections were common, affecting 22.3% of preschool children, 31.6% of school-aged children and 28.0% of mothers. CONCLUSIONS: Here we report prevalence levels of malaria, schistosomiasis and geohelminths; all endemic in this poorly described area where a DSS has been recently established. Furthermore we found evidence that the studied infections are associated with the observed levels of anemia and malnutrition, which can justify the implementation of integrated interventions for the control of these diseases and morbidities.


Asunto(s)
Anemia/epidemiología , Infecciones por Uncinaria/epidemiología , Malaria Falciparum/epidemiología , Desnutrición/epidemiología , Vigilancia de la Población , Esquistosomiasis/epidemiología , Adolescente , Adulto , Angola/epidemiología , Animales , Niño , Preescolar , Comorbilidad , Estudios Transversales , Heces/parasitología , Femenino , Infecciones por Uncinaria/parasitología , Humanos , Lactante , Malaria Falciparum/parasitología , Masculino , Prevalencia , Esquistosomiasis/parasitología
16.
PLoS Negl Trop Dis ; 5(1): e938, 2011 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-21245910

RESUMEN

BACKGROUND: in uganda, control of intestinal schistosomiasis with preventive chemotherapy is typically focused towards treatment of school-aged children; the needs of younger children are presently being investigated as in lakeshore communities very young children can be infected. In the context of future epidemiological monitoring, we sought to compare the detection thresholds of available diagnostic tools for Schistosoma mansoni and estimate a likely age of first infection for these children. METHODS AND FINDINGS: a total of 242 infants and preschool children (134 boys and 108 girls, mean age 2.9 years, minimum 5 months and maximum 5 years) were examined from Bugoigo, a well-known disease endemic village on Lake Albert. Schistosome antigens in urine, eggs in stool and host antibodies to eggs were inspected to reveal a general prevalence of 47.5% (CI(95) 41.1-54.0%), as ascertained by a positive criterion from at least one diagnostic method. Although children as young as 6 months old could be found infected, the average age of infected children was between 3»-3¾ years, when diagnostic techniques became broadly congruent. CONCLUSION: whilst different assays have particular (dis)advantages, direct detection of eggs in stool was least sensitive having a temporal lag behind antigen and antibody methods. Setting precisely a general age of first infection is problematic but if present Ugandan policies continue, a large proportion of infected children could wait up to 3-4 years before receiving first medication. To better tailor treatment needs for this younger ageclass, we suggest that the circulating cathodic antigen urine dipstick method to be used as an epidemiological indicator.


Asunto(s)
Anticuerpos Antihelmínticos/sangre , Antígenos Helmínticos/orina , Heces/parasitología , Schistosoma mansoni/aislamiento & purificación , Esquistosomiasis mansoni/diagnóstico , Esquistosomiasis mansoni/epidemiología , Animales , Preescolar , Femenino , Humanos , Lactante , Masculino , Sensibilidad y Especificidad , Uganda/epidemiología
17.
Am J Trop Med Hyg ; 83(5): 1048-55, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-21036836

RESUMEN

To control intestinal schistosomiasis at a national level in sub-Saharan Africa, there is a need for field-applicable markers to measure morbidity associated with this disease. The purpose of this study was to determine whether fecal calprotectin or fecal occult blood assays could be used as morbidity indicators for intestinal schistosomiasis. The study was carried out in Uganda with a cohort of young children (n = 1,327) and their mothers (n = 726). The prevalence of egg-patent schistosomiasis was 27.2% in children and 47.6% in mothers. No association was found between schistosomiasis infection and fecal calprotectin in children (n = 83, odds ratio [OR] = 1.08, P = 0.881), although an inverse relationship (n = 58, OR = 0.17, P = 0.043) was found in mothers. Fecal occult blood was strongly associated with Schistosoma mansoni infection in children (n = 814, OR = 2.30, P < 0.0001) and mothers (n = 448, OR = 1.95, P = 0.004). Fecal occult blood appears to be useful for measuring morbidity associated with intestinal schistosomiasis and could be used in assessing the impact of control programs upon disease.


Asunto(s)
Esquistosomiasis mansoni/epidemiología , Adolescente , Adulto , Anciano , Albendazol/uso terapéutico , Antihelmínticos/uso terapéutico , Niño , Preescolar , Heces/química , Femenino , Humanos , Lactante , Complejo de Antígeno L1 de Leucocito/análisis , Persona de Mediana Edad , Morbilidad , Sangre Oculta , Oportunidad Relativa , Praziquantel/uso terapéutico , Prevalencia , Esquistosomiasis mansoni/diagnóstico , Esquistosomiasis mansoni/tratamiento farmacológico , Uganda/epidemiología , Adulto Joven
18.
Trans R Soc Trop Med Hyg ; 104(11): 740-2, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20832093

RESUMEN

In large-scale interventions for control of schistosomiasis, use of the WHO dose pole is favoured for mass drug administration of praziquantel. Application of this simple tool has enabled pragmatic tablet dosing using patient height as a proxy for bodyweight, allowing control programmes to expand into resource-poor settings. Here we briefly summarize the inception and development of the existing WHO dose pole and discuss a proposed update which now permits dosing of infants and preschool children (height<94cm). Using this pole, we suggest that mass drug administration can be better optimized, streamlining general treatment to reduce drug wastage which could lead to significant programmatic savings and allocation of treatments to younger children with minimal additional cost.


Asunto(s)
Antihelmínticos/administración & dosificación , Praziquantel/administración & dosificación , Esquistosomiasis/tratamiento farmacológico , África del Sur del Sahara/epidemiología , Antihelmínticos/economía , Estatura , Preescolar , Protocolos Clínicos , Análisis Costo-Beneficio , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Lactante , Masculino , Praziquantel/economía , Esquistosomiasis/economía , Esquistosomiasis/epidemiología , Resultado del Tratamiento
19.
Malar J ; 9: 245, 2010 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-20799940

RESUMEN

BACKGROUND: Prompt and correct diagnosis of malaria is crucial for accurate epidemiological assessment and better case management, and while the gold standard of light microscopy is often available, it requires both expertise and time. Portable fluorescent microscopy using the CyScope offers a potentially quicker, easier and more field-applicable alternative. This article reports on the strengths, limitations of this methodology and its diagnostic performance in cross-sectional surveys on young children and women of child-bearing age. METHODS: 552 adults (99% women of child-bearing age) and 980 children (99% ≤ 5 years of age) from rural and peri-urban regions of Ugandan were examined for malaria using light microscopy (Giemsa-stain), a lateral-flow test (Paracheck-Pf) and the CyScope. Results from the surveys were used to calculate diagnostic performance (sensitivity and specificity) as well as to perform a receiver operating characteristics (ROC) analyses, using light microscopy as the gold-standard. RESULTS: Fluorescent microscopy (qualitative reads) showed reduced specificity (<40%), resulting in higher community prevalence levels than those reported by light microscopy, particularly in adults (+180% in adults and +20% in children). Diagnostic sensitivity was 92.1% in adults and 86.7% in children, with an area under the ROC curve of 0.63. Importantly, optimum performance was achieved for higher parasitaemia (>400 parasites/µL blood): sensitivity of 64.2% and specificity of 86.0%. Overall, the diagnostic performance of the CyScope was found inferior to that of Paracheck-Pf. DISCUSSION: Fluorescent microscopy using the CyScope is certainly a field-applicable and relatively affordable solution for malaria diagnoses especially in areas where electrical supplies may be lacking. While it is unlikely to miss higher parasitaemia, its application in cross-sectional community-based studies leads to many false positives (i.e. small fluorescent bodies of presently unknown origin mistaken as malaria parasites). Without recourse to other technologies, arbitration of these false positives is presently equivocal, which could ultimately lead to over-treatment; something that should be further explored in future investigations if the CyScope is to be more widely implemented.


Asunto(s)
Pruebas Diagnósticas de Rutina/métodos , Malaria/diagnóstico , Microscopía Fluorescente/métodos , Parasitología/métodos , Adolescente , Adulto , Preescolar , Estudios Transversales , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Curva ROC , Población Rural , Factores de Tiempo , Uganda , Adulto Joven
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