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1.
BMC Infect Dis ; 20(1): 12, 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31906872

RESUMO

BACKGROUND: Determination of the prevalence and distribution pattern of intestinal parasites is a fundamental step to set up an effective control program to improve the health status. This study aimed to determine the prevalence of intestinal parasitic infections and associated risk factors among inhabitants of Rudbar-e Jonub county, southeast of Kerman province, southeastern Iran. METHODS: In this cross-sectional study, 861 stool specimens were collected from inhabitants of Rudbar-e Jonub county through a multistage cluster sampling method in 2018. The collected specimens were examined by parasitological methods including, direct wet-mounting (for the fresh specimens with a watery consistency), formalin-ethyl acetate sedimentation and agar plate culture. RESULTS: The prevalence of intestinal parasites was 34.2% (95% CI 30.1 to 38.2). The prevalence of protozoan parasites 32.3% (95% CI 28.4 to 36.5) was significantly higher than helminthic parasites 3.2% (95% CI 2.1 to 4.7). Blastocystis sp. (13.3%), Entamoeba coli (11.4%) and Giardia lamblia (10.6%) as protozoan parasite and Hymenolepis nana (2.4%) as helminthic parasite were the most common detected intestinal parasites in the study. Entamoeba histolytica/dispar (1.5%), Iodamoeba bütschlii (1.0%), Chilomastix mesnili (0.5%), Entamoeba hartmanni (0.4%), Enterobius vermicularis (0.3%) and Ascaris lambercoides (0.3%) were other detected parasites. Multiple logistic regression revealed a significant association of intestinal parasitic infections with source of drinking water and residency status (rural/urban). Multiple infections with 2 or 3 parasitic agents constituted 22.7% of 295 infected cases. CONCLUSIONS: This study revealed a high prevalence of intestinal protozoan infections among inhabitants of Rudbar-e Jonub county. Intestinal parasites especially protozoans remain a challenging public health problem wherever sanitation and health measures are limited in Iran.


Assuntos
Enteropatias Parasitárias/epidemiologia , Adolescente , Adulto , Animais , Criança , Estudos Transversais , Fezes/parasitologia , Feminino , Helmintíase/epidemiologia , Helmintíase/parasitologia , Humanos , Enteropatias Parasitárias/parasitologia , Irã (Geográfico)/epidemiologia , Masculino , Pessoa de Meia-Idade , Parasitos/classificação , Prevalência , Infecções por Protozoários/epidemiologia , Infecções por Protozoários/parasitologia , Fatores de Risco , Adulto Jovem
2.
PLoS Negl Trop Dis ; 13(10): e0007778, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31658264

RESUMO

BACKGROUND: A DNA extraction and preservation protocol that yields sufficient and qualitative DNA is pivotal for the success of any nucleic acid amplification test (NAAT), but it still poses a challenge for soil-transmitted helminths (STHs), including Ascaris lumbricoides, Trichuris trichiura and the two hookworms (Necator americanus and Ancylostoma duodenale). In the present study, we assessed the impact of different DNA extraction and preservativation protocols on STH-specific DNA amplification from stool. METHODOLOGY AND PRINCIPAL FINDINGS: In a first experiment, DNA was extracted from 37 stool samples with variable egg counts for T. trichiura and N. americanus applying two commercial kits, both with and without a prior bead beating step. The DNA concentration of T. trichiura and N. americanus was estimated by means of qPCR. The results showed clear differences in DNA concentration across both DNA extraction kits, which varied across both STHs. They also indicated that adding a bead beating step substantially improved DNA recovery, particularly when the FECs were high. In a second experiment, 20 stool samples with variable egg counts for A. lumbricoides, T. trichiura and N. americanus were preserved in either 96% ethanol, 5% potassium dichromate or RNAlater and were stored at 4°C for 65, 245 and 425 days. DNA was extracted using the DNeasy Blood & Tissue kit with a bead beating step. Stool samples preserved in ethanol proved to yield higher DNA concentrations as FEC increased, although stool samples appeared to be stable over time in all preservatives. CONCLUSIONS: The choice of DNA extraction kit significantly affects the outcome of NAATs. Given the clear benefit of bead beating and our validation of ethanol for (long-term) preservation, we recommend that these aspects of the protocol should be adopted by any stool sampling and DNA extraction protocol for downstream NAAT-based detection and quantification of STHs.


Assuntos
Fezes/parasitologia , Helmintíase/diagnóstico , Helmintos/isolamento & purificação , Técnicas de Diagnóstico Molecular/métodos , Preservação Biológica/métodos , Solo/parasitologia , Adolescente , Ancylostoma/genética , Ancylostoma/isolamento & purificação , Ancylostomatoidea/genética , Ancylostomatoidea/isolamento & purificação , Ancylostomatoidea/parasitologia , Animais , Ascaríase/diagnóstico , Ascaríase/parasitologia , Ascaris lumbricoides/genética , Ascaris lumbricoides/isolamento & purificação , Criança , Pré-Escolar , DNA/isolamento & purificação , Helmintíase/parasitologia , Helmintos/genética , Humanos , Necator americanus/isolamento & purificação , Necatoríase/diagnóstico , Necatoríase/patologia , Contagem de Ovos de Parasitas , Sensibilidade e Especificidade , Tricuríase/diagnóstico , Tricuríase/parasitologia , Trichuris/genética , Trichuris/isolamento & purificação
3.
Dokl Biol Sci ; 487(1): 101-104, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31571075

RESUMO

In this ecological and physiological study of the common eider (Somateria mollissima) nesting on the coast of Eastern Murman, the species composition of the bird helminth fauna, as well as the infection quantitative parameters, were determined. The common eider small intestine proved to be infected with trematodes of the genus Microphallus; three species of cestodes, namely, Lateriporus teres (Cestoda: Dilepididae), Fimbriarioides intermedia (Cestoda: Hymenolepididae), and Microsomacanthus diorchis (Cestoda: Hymenolepididae); and one species of acanthocephalan, Polymorphus phippsi (Palaeacanthocephala: Polymorphidae). At the sites of F. intermedia and M. diorchis locations within the intestine, the protease activity was reduced while in the foci infected with acanthocephalan P. phippsi, it was, on the contrary, increased. Glycosidase activity in the intestinal mucosa was reduced as compared to the control in birds infected by the cestodes M. diorchis. Hematological indices of the infected individuals were higher than the control parameters.


Assuntos
Anseriformes/parasitologia , Doenças das Aves/parasitologia , Helmintíase/parasitologia , Intestino Delgado/parasitologia , Acantocéfalos/patogenicidade , Animais , Proteínas Aviárias/metabolismo , Doenças das Aves/metabolismo , Cestoides/patogenicidade , Glicosídeo Hidrolases/metabolismo , Helmintíase/metabolismo , Mucosa Intestinal/metabolismo , Peptídeo Hidrolases/metabolismo , Trematódeos/patogenicidade
4.
Dokl Biol Sci ; 487(1): 108-111, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31571077

RESUMO

Progressive expansion of the most hazardous human parasitoses caused by trematodes, cestodes and nematodes has been found on the south of the Russian Far East. Decelerating expansion of the trematode Clonorchis sinensis, an agent of clonorchiasis towards the southern Primorye Territory from the Amur River basin, that began 10-15 years ago, was revealed. A prognosis was made on the activation of the natural foci of clonorchiasis and paragonimiasis. Circulation possibilities are discussed of the highly pathogenic trematode Pagonimus heterotremusar in the South Asian regional ecosystems. Our experiments showed that the freshwater gastropods of the Parajuga genus from the Amur River basin and those of Stenothyra genus from Primorsky Territory were resistant to this trematode infection. Nevertheless, this does not exclude the possibility of this parasite penetration into the Far East region via infection of the local gastropods of other genera.


Assuntos
Reservatórios de Doenças/parasitologia , Helmintíase/parasitologia , Animais , Canidae/parasitologia , Cestoides/patogenicidade , Clima , Demografia/estatística & dados numéricos , Felidae/parasitologia , Peixes/parasitologia , Helmintíase/epidemiologia , Helmintíase/transmissão , Humanos , Moluscos/parasitologia , Nematoides/patogenicidade , Sibéria , Trematódeos/patogenicidade
5.
Infect Dis Poverty ; 8(1): 82, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31575378

RESUMO

BACKGROUND: The goal of soil-transmitted helminthiases (STH) control programmes is to eliminate STH-associated morbidity in the target population by reducing the prevalence of moderate- and heavy-intensity infections and the overall STH infection prevalence mainly through preventive chemotherapy (PC) with either albendazole or mebendazole. Endemic countries should measure the success of their control programmes through regular epidemiological assessments. We evaluated changes in STH prevalence in countries that conducted effective PC coverage for STH to guide changes in the frequency of PC rounds and the number of tablets needed. METHODS: We selected countries from World Health Organization (WHO)'s Preventive Chemotherapy and Transmission control (PCT) databank that conducted ≥5 years of PC with effective coverage for school-age children (SAC) and extracted STH baseline and impact assessment data using the WHO Epidemiological Data Reporting Form, Ministry of Health reports and/or peer-reviewed publications. We used pooled and weighted means to plot the prevalence of infection with any STH and with each STH species at baseline and after ≥5 years of PC with effective coverage. Finally, using the WHO STH decision tree, we estimated the reduction in the number of tablets needed. RESULTS: Fifteen countries in four WHO regions conducted annual or semi-annual rounds of PC for STH for 5 years or more and collected data before and after interventions. At baseline, the pooled prevalence was 48.9% (33.1-64.7%) for any STH, 23.2% (13.7-32.7%) for Ascaris lumbricoides, 21.01% (9.7-32.3%) for Trichuris trichiura and 18.2% (10.9-25.5%) for hookworm infections, while after ≥5 years of PC for STH, the prevalence was 14.3% (7.3-21.3%) for any STH, 6.9% (1.3-12.5%) for A. lumbricoides, 5.3% (1.06-9.6%) for T. trichiura and 8.1% (4.0-12.2%) for hookworm infections. CONCLUSIONS: Countries endemic for STH have made tremendous progress in reducing STH-associated morbidity, but very few countries have data to demonstrate that progress. In this study, the data show that nine countries should adapt their PC strategies and the frequency of PC rounds to yield a 36% reduction in drug needs. The study also highlights the importance of impact assessment surveys to adapt control strategies according to STH prevalence.


Assuntos
Albendazol/uso terapêutico , Anti-Helmínticos/uso terapêutico , Quimioprevenção/estatística & dados numéricos , Helmintíase/prevenção & controle , Mebendazol/uso terapêutico , Albendazol/provisão & distribução , Animais , Anti-Helmínticos/provisão & distribução , Ascaríase/epidemiologia , Ascaríase/parasitologia , Ascaríase/prevenção & controle , Ascaris lumbricoides/fisiologia , Helmintíase/epidemiologia , Helmintíase/parasitologia , Infecções por Uncinaria/epidemiologia , Infecções por Uncinaria/parasitologia , Infecções por Uncinaria/prevenção & controle , Humanos , Mebendazol/provisão & distribução , Prevalência , Solo/parasitologia , Tricuríase/epidemiologia , Tricuríase/parasitologia , Tricuríase/prevenção & controle , Trichuris/fisiologia
6.
PLoS Negl Trop Dis ; 13(10): e0007776, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31618208

RESUMO

We investigated the impact of helminths and malaria infection on Kaposi's sarcoma associated herpesvirus (KSHV) seropositivity, using samples and data collected from a cluster-randomised trial of intensive versus standard anthelminthic treatment. The trial was carried out in 2012 to 2016 among fishing communities on Lake Victoria islands in Uganda. Plasma samples from 2881 participants from two household surveys, the baseline (1310 participants) and the final (1571 participants) surveys were tested for KSHV IgG antibody responses to K8.1 and ORF73 recombinant proteins using ELISA. The baseline survey was carried out before the trial intervention while the final survey was carried out after three years of the trial intervention. Additionally, a subset sample of 372 participants from the final survey was tested for IgE, IgG and IgG4 antibody concentrations to S. mansoni adults worm antigen (SWA) and S. mansoni egg antigen (SEA) using ELISA. Infection by helminths (S. mansoni, N. americanus, T. trichiura and S. stercoralis) was diagnosed using real-time PCR, urine circulating cathodic antigen (CCA) and stool microscopy (Kato-Katz method) while malaria infection was diagnosed using microscopy. We analysed the relationship between helminth and malaria infections and KSHV seropositivity using regression modelling, allowing for survey design. At baseline, 56% of the participants were male while 48% of the participants were male in the final survey. The most prevalent helminth infection was S. mansoni (at baseline 52% and 34% in the final survey by microscopy, 86% by CCA and 50% by PCR in the final survey). KSHV seropositivity was 66% (baseline) and 56% (final survey) among those 1-12 years and >80% in those 13+ years in both surveys; malaria parasitaemia prevalence was 7% (baseline) and 4% (final survey). At baseline, individuals infected with S. mansoni (detected by microscopy) were more likely to be KSHV seropositive (aOR = 1.86 (1.16, 2.99) p = 0.012) and had higher anti-K8.1 antibody levels (acoefficient = 0.03 (0.01, 0.06) p = 0.02). In the final survey, S. mansoni (by microscopy, adjusted Odds Ratio (aOR = 1.43 (1.04-1.95), p = 0.028) and malaria parasitaemia (aOR = 3.49 (1.08-11.28), p = 0.038) were positively associated with KSHV seropositivity. Additionally, KSHV seropositive participants had higher S. mansoni-specific IgE and IgG antibody concentrations in plasma. Furthermore, HIV infected individuals on cART were less likely to be KSHV seropositive compared to HIV negative individuals (aOR = 0.46 (0.30, 0.71) p = 0.002). Schistosoma species skew the immune response towards Th2 and regulatory responses, which could impact on KSHV reactivation if co-infected with both organisms.


Assuntos
Antígenos de Helmintos/imunologia , Herpesvirus Humano 8/imunologia , Doenças Parasitárias/epidemiologia , Doenças Parasitárias/imunologia , Adolescente , Adulto , Idoso , Albendazol/uso terapêutico , Animais , Anticorpos Anti-Helmínticos/sangue , Criança , Pré-Escolar , Estudos Transversais , Infecções por HIV/imunologia , Helmintíase/tratamento farmacológico , Helmintíase/epidemiologia , Helmintíase/imunologia , Helmintíase/parasitologia , Humanos , Imunoglobulina E/sangue , Imunoglobulina G/sangue , Lactente , Ilhas , Lagos , Malária/imunologia , Pessoa de Meia-Idade , Razão de Chances , Doenças Parasitárias/tratamento farmacológico , Doenças Parasitárias/fisiopatologia , Praziquantel/uso terapêutico , Prevalência , Schistosoma mansoni/imunologia , Esquistossomose mansoni/epidemiologia , Uganda/epidemiologia , Adulto Jovem
7.
Nat Commun ; 10(1): 4408, 2019 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-31562318

RESUMO

Intestinal epithelial cells (IEC) have important functions in nutrient absorption, barrier integrity, regeneration, pathogen-sensing, and mucus secretion. Goblet cells are a specialized cell type of IEC that secrete Trefoil factor 3 (TFF3) to regulate mucus viscosity and wound healing, but whether TFF3-responsiveness requires a receptor is unclear. Here, we show that leucine rich repeat receptor and nogo-interacting protein 2 (LINGO2) is essential for TFF3-mediated functions. LINGO2 immunoprecipitates with TFF3, co-localizes with TFF3 on the cell membrane of IEC, and allows TFF3 to block apoptosis. We further show that TFF3-LINGO2 interactions disrupt EGFR-LINGO2 complexes resulting in enhanced EGFR signaling. Excessive basal EGFR activation in Lingo2 deficient mice increases disease severity during colitis and augments immunity against helminth infection. Conversely, TFF3 deficiency reduces helminth immunity. Thus, TFF3-LINGO2 interactions de-repress inhibitory LINGO2-EGFR complexes, allowing TFF3 to drive wound healing and immunity.


Assuntos
Colite/imunologia , Receptores ErbB/imunologia , Helmintíase/imunologia , Mucosa Intestinal/imunologia , Proteínas de Membrana/metabolismo , Proteínas do Tecido Nervoso/imunologia , Fator Trefoil-3/imunologia , Animais , Linhagem Celular Tumoral , Colite/induzido quimicamente , Colite/metabolismo , Sulfato de Dextrana , Receptores ErbB/genética , Receptores ErbB/metabolismo , Células Caliciformes/imunologia , Células Caliciformes/metabolismo , Células Caliciformes/parasitologia , Células HEK293 , Helmintíase/metabolismo , Helmintíase/parasitologia , Helmintos/imunologia , Helmintos/fisiologia , Humanos , Mucosa Intestinal/metabolismo , Mucosa Intestinal/parasitologia , Proteínas de Membrana/genética , Camundongos Endogâmicos C57BL , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Organofosfonatos , Fator Trefoil-3/genética , Fator Trefoil-3/metabolismo , Células U937
8.
Pan Afr Med J ; 33: 94, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31489072

RESUMO

Introduction: Soil-transmitted helminth infections (STHs) and schistosomiasis have serious consequences for the health, education and nutrition of children in developing countries. As Loum is known as a highly endemic commune for these infections, several deworming campaigns have been carried out in the past. The purpose of this study was to determine any changes that have occurred since then in the characteristics of these infections among schoolchildren in this site. Methods: A cross-sectional study was conducted in October 2016 on 289 schoolchildren. Stool and urine samples were collected and examined to determine the prevalence and intensity of helminth infections. Results: The highest prevalence was noted for Schistosoma haematobium (34.2%), followed by Ascaris lumbricoides (8.6%), S. mansoni (4.9%) and Trichuris trichiura (4.9%) in decreasing order. A prevalence of less than 2% was noted for each of the other two helminths. The highest mean intensity was found for S. haematobium (39.6 eggs/10 ml of urine), followed by A. lumbricoides (24.2 eggs per gram of faeces: epg), Strongyloides stercoralis (16.6 epg) and Schistosoma mansoni (12.3 epg). The prevalence of T. trichiura was significantly higher in boys and that of S. haematobium in children aged 10 years or older, while the differences between other values of prevalence or between egg burdens were not significant. Conclusion: Compared with values reported in 2003, the prevalence and intensity of schistosomiases and STH infections in Loum has sharply decreased in 2016. Confirmation of this decrease in the years to come allowed to space deworming campaigns among schoolchildren.


Assuntos
Anti-Helmínticos/administração & dosagem , Helmintíase/epidemiologia , Esquistossomose/epidemiologia , Solo/parasitologia , Adolescente , Camarões/epidemiologia , Criança , Pré-Escolar , Estudos Transversais , Fezes/parasitologia , Feminino , Helmintíase/tratamento farmacológico , Helmintíase/parasitologia , Humanos , Masculino , Prevalência , Esquistossomose/tratamento farmacológico , Esquistossomose/parasitologia , Fatores Sexuais
9.
PLoS Negl Trop Dis ; 13(8): e0007446, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31369558

RESUMO

BACKGROUND: Because the success of deworming programs targeting soil-transmitted helminths (STHs) is evaluated through the periodically assessment of prevalence and infection intensities, the use of the correct diagnostic method is of utmost importance. The STH community has recently published for each phase of a deworming program the minimal criteria that a potential diagnostic method needs to meet, the so-called target product profiles (TPPs). METHODOLOGY: We compared the diagnostic performance of a single Kato-Katz (reference method) with that of other microscopy-based methods (duplicate Kato-Katz, Mini-FLOTAC and FECPAKG2) and one DNA-based method (qPCR) for the detection and quantification of STH infections in three drug efficacy trials in Ethiopia, Lao PDR, and Tanzania. Furthermore, we evaluated a selection of minimal diagnostic criteria of the TPPs. PRINCIPAL FINDINGS: All diagnostic methods showed a clinical sensitivity of ≥90% for all STH infections of moderate-to-heavy intensities. For infections of very low intensity, only qPCR resulted in a sensitivity that was superior to a single Kato-Katz for all STHs. Compared to the reference method, both Mini-FLOTAC and FECPAKG2 resulted in significantly lower fecal egg counts for some STHs, leading to a substantial underestimation of the infection intensity. For qPCR, there was a positive significant correlation between the egg counts of a single Kato-Katz and the DNA concentration. CONCLUSIONS/SIGNIFICANCE: Our results indicate that the diagnostic performance of a single Kato-Katz is underestimated by the community and that diagnostic specific thresholds to classify intensity of infection are warranted for Mini-FLOTAC, FECPAKG2 and qPCR. When we strictly apply the TPPs, Kato-Katz is the only microscopy-based method that meets the minimal diagnostic criteria for application in the planning, monitoring and evaluation phase of an STH program. qPCR is the only method that could be considered in the phase that aims to seek confirmation for cessation of program. TRIAL REGISTRATION: ClinicalTrials.gov NCT03465488.


Assuntos
Testes Diagnósticos de Rotina/métodos , Helmintíase/parasitologia , Helmintíase/transmissão , Helmintos/isolamento & purificação , Técnicas de Diagnóstico Molecular/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Solo/parasitologia , Adolescente , Animais , Brasil , Criança , Testes Diagnósticos de Rotina/instrumentação , Etiópia/epidemiologia , Fezes/parasitologia , Feminino , Helmintíase/diagnóstico , Helmintíase/epidemiologia , Helmintos/genética , Humanos , Laos/epidemiologia , Masculino , Microscopia , Técnicas de Diagnóstico Molecular/instrumentação , Contagem de Ovos de Parasitas/métodos , Prevalência , Sensibilidade e Especificidade , Tanzânia/epidemiologia , Organização Mundial da Saúde
10.
BMC Infect Dis ; 19(1): 734, 2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31438865

RESUMO

BACKGROUND: Schistosomiasis and soil-transmitted helminth infections are among the most chronic infections worldwide. Based on their demonstrable impact on human health, the WHO recently recommended the implementation of robust strategies aimed at controlling or eliminating schistosomiasis and soil-transmitted helminths by 2020. The implementation of this strategy, however, warrants a clear understanding of the community's knowledge, attitudes and practices in relation to these infections. This study sought to identify sociocultural gaps that should be addressed to ensure the success of cost-effective community-based schistosomiasis-soil-transmitted helminths control and elimination programs. METHODS: This was a cross-sectional mixed methodology study. Quantitative data were collected using a structured questionnaire from 442 caregivers of preschool aged children. In-depth interviews and focus group discussions were conducted among caregivers, preschool teachers, traditional authorities and community caregivers. All interviews were captured using an audio recorder to maximize accuracy. Quantitative data were analysed using bivariate and multivariate techniques while qualitative data were analysed thematically. RESULTS: Findings reflected inadequate knowledge, attitudes and practices in relation to schistosomiasis and soil-transmitted helminths while awareness of schistosomiasis and soil-transmitted helminths was high (87.1 and 79.2% respectively). Correct knowledge on transmission, prevention, signs and symptoms and life cycle was low (below 50%) for both infections among those who had heard of the disease. From multivariate analysis, being aged at least 35 years increased the odds of reporting good practices on schistosomiasis by 65% (COR 1.652, 95% CI: 1.073-2.543) while receiving health information through community meetings (COR 0.072, 95% CI: 0.010-0.548) significantly reduced the odds of having good knowledge on schistosomiasis. CONCLUSIONS: These findings are valuable in designing behavioural change approaches towards enhancing health outcomes through community-based interventions to ensure effective control and elimination of schistosomiasis and soil-transmitted helminths. There is a critical need for channelling efforts towards making health education the core of schistosomiasis and soil-transmitted helminths programs aimed at achieving intensified control or elimination of these infections by 2020.


Assuntos
Cuidadores , Conhecimentos, Atitudes e Prática em Saúde , Esquistossomose , Adulto , Idoso , Animais , Cuidadores/psicologia , Cuidadores/normas , Cuidadores/estatística & dados numéricos , Criança , Pré-Escolar , Estudos Transversais , Feminino , Grupos Focais , Educação em Saúde , Helmintíase/parasitologia , Helmintos , Humanos , Masculino , Pessoa de Meia-Idade , Esquistossomose/parasitologia , Esquistossomose/terapia , Esquistossomose/transmissão , Professores Escolares/normas , Professores Escolares/estatística & dados numéricos , Solo/parasitologia , África do Sul/epidemiologia , Inquéritos e Questionários
11.
Immunol Allergy Clin North Am ; 39(3): 417-427, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31284930

RESUMO

Helminth infections may inhibit the development of allergic diseases, including asthma. On the other hand, some helminth species may induce or worsen symptoms of asthma. This article discusses the impact of helminth infections on asthma as well as the potencial of helminth-derived molecules with regulatory characteristics in the prevention or treatment of this disease. The ability to induce regulation has been observed in animal models of asthma or cells of asthmatic individuals in vitro. Potential future clinical applications of helminth antigens or infection for prevention of asthma merit further translational research.


Assuntos
Asma/etiologia , Suscetibilidade a Doenças , Helmintíase/complicações , Helmintíase/imunologia , Helmintos/imunologia , Interações Hospedeiro-Parasita , Animais , Anti-Helmínticos/farmacologia , Anti-Helmínticos/uso terapêutico , Suscetibilidade a Doenças/imunologia , Helmintíase/tratamento farmacológico , Helmintíase/parasitologia , Interações Hospedeiro-Parasita/imunologia , Humanos , Imunomodulação/efeitos dos fármacos
12.
Infect Immun ; 87(10)2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31285249

RESUMO

Granuloma formation is a key host immune response generated to confine invading pathogens and limit extensive host damage. It consists of an accumulation of host immune cells around a pathogen. This host response has been extensively studied in the context of inflammatory diseases. However, there is much less known about Th2-type granulomas generated in response to parasitic worms. Based on in vitro data, innate immune cells within the granuloma are thought to immobilize and kill parasites but also act to repair damaged tissue. Understanding this dual function is key. The two billion people and many livestock/wild animals infected with helminths demonstrate that granulomas are not effective at clearing infection. However, the lack of high mortality highlights their importance in ensuring that parasite migration/tissue damage is restricted and wound healing is effective. In this review, we define two key cellular players (macrophages and eosinophils) and their associated molecular players involved in Th2 granuloma function. To date, the underlying mechanisms remain poorly understood, which is in part due to a lack of conclusive studies. Most have been performed in vitro rather than in vivo, using cells that have not been obtained from granulomas. Experiments using genetically modified mouse strains and/or antibody/chemical-mediated cell depletion have also generated conflicting results depending on the model. We discuss the caveats of previous studies and the new tools available that will help fill the gaps in our knowledge and allow a better understanding of the balance between immune killing and healing.


Assuntos
Eosinófilos/imunologia , Granuloma/imunologia , Helmintíase/imunologia , Helmintos/imunologia , Mucosa Intestinal/imunologia , Macrófagos/imunologia , Células Th2/imunologia , Animais , Comunicação Celular , Citocinas/biossíntese , Citocinas/imunologia , Modelos Animais de Doenças , Eosinófilos/parasitologia , Eosinófilos/patologia , Granuloma/parasitologia , Granuloma/patologia , Helmintíase/parasitologia , Helmintíase/patologia , Helmintos/crescimento & desenvolvimento , Helmintos/patogenicidade , Interações Hospedeiro-Parasita/imunologia , Humanos , Imunidade Inata , Mucosa Intestinal/patologia , Macrófagos/parasitologia , Macrófagos/patologia , Camundongos , Células Th2/parasitologia , Células Th2/patologia , Cicatrização/imunologia
13.
BMC Infect Dis ; 19(1): 659, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31340774

RESUMO

BACKGROUND: It is estimated that over a third of the world population is infected by malaria and helminthiases mainly among communities with high poverty indices. The distribution of these parasitic infections overlaps in many epidemiological settings and have varying outcomes in the host. In this paper we report the prevalence of malaria and intestinal helminthiases coinfections among malaria suspected patients and the association of helminthiases with the occurrence of malaria and its outcomes in Wondo Genet, southern Ethiopia. METHODS: In a cross-sectional study conducted from December 2009 to July 2010 in Kella, Aruma and Busa Health Centers in Wondo Genet, a total of 427 consenting febrile patients were screened for malaria and intestinal helminths infections. Malaria parasite detection and quantification were done using Giemsa stained thick and thin blood films. Helminth infections were screened and quantified by Kato-Katz thick smear method. Haemoglobin level was assessed using haemocue machine (HemoCue HB 201+). Difference in proportions and means were tested by Student's t test and ANOVA while logistic regression analysis was used to determine the association between variables. RESULTS: Of the total examined, 196 (45.90%) were positive for at least one helminth infection while 276 (64.64%) were positive for malaria. The prevalence of Plasmodium falciparum and P. vivax infections were 47.31 and 16.62%, respectively. The most common helminth parasites detected were Ascaris lumbricoides (33.96%), Trichuris trichiura (21.55%), Schistosoma mansoni (13.35%), and hookworms (6.79%). The overall malaria-helminthiases coinfection was 33.96%. The prevalence of anaemia was 43.12%. Helminthiases coinfection showed a positive correlation with the occurrence of malaria (AOR = 2.17, 95% CI: 1.44-3.28; P < 0.001). Schistosoma mansoni coinfection was associated with the increased risk of developing malaria associated anaemia (OR = 14.4, 95% CI: 1.37-150.80; P = 0.026). CONCLUSION: Malaria and helminth coinfections are important causes of morbidities among the population in Wondo Genet necessitating integrated control measures. Nevertheless, further detailed studies on the consequences and pathogenesis of these coinfections are needed to institute sound control and intervention measures.


Assuntos
Coinfecção/epidemiologia , Helmintíase/epidemiologia , Enteropatias Parasitárias/epidemiologia , Malária/epidemiologia , Adolescente , Adulto , Idoso , Animais , Criança , Coinfecção/parasitologia , Coinfecção/prevenção & controle , Comorbidade , Estudos Transversais , Etiópia/epidemiologia , Feminino , Febre/epidemiologia , Febre/parasitologia , Helmintíase/parasitologia , Helmintíase/prevenção & controle , Helmintos/genética , Helmintos/isolamento & purificação , Humanos , Enteropatias Parasitárias/parasitologia , Enteropatias Parasitárias/prevenção & controle , Malária/parasitologia , Malária/prevenção & controle , Masculino , Pessoa de Meia-Idade , Pacientes Ambulatoriais , Plasmodium falciparum/genética , Plasmodium falciparum/isolamento & purificação , Prevalência , Viverridae , Adulto Jovem
14.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi ; 31(2): 148-154, 2019 May 08.
Artigo em Chinês | MEDLINE | ID: mdl-31184045

RESUMO

OBJECTIVE: To understand and analyze the epidemic status of human intestinal parasitic diseases in the ecological region of the Qinba Mountains in Henan Province, so as to provide the evidence for the control of the diseases in this region. METHODS: According to the methods of National Survey Scheme on Major Human Parasitic Diseases, 26 survey spots were selected in 8 counties (cities) in ecological regions of Qinba Mountains in Henan Province in 2015. After collecting the human fecal samples, the eggs of intestinal helminthes were detected with the modified Kato-Katz thick smear method, the species of Ancylostoma of the hookworm egg-positive samples were identified with the tube fecal culture method, the eggs of Enterobius vermicularis were detected by using the adhesive tape method in children aged 3 to 6 years, and the cyst and trophozoite of intestinal protozoa were examined by iodine staining. The infections of intestinal parasites in different populations and the related influencing factors were analyzed. RESULTS: Totally 6 706 residents were recruited in this study, 8 kinds of parasites were found including 3 species of helminthes and 5 species of protozoans. The overall infection rate of intestinal parasites was 3.39%, covering 2.92% for helminthes and 0.49% for protozoans. The infection rate of E. vermicularis in children aged 3 to 6 years was 3.93%. The 3 identified helminthes were Ascaris lumbricoides, E. vermicularis, and Dicrocoelium dendriticum, with the highest infection rate of E. vermicularis (2.68%, χ2 = 306.362, P < 0.05). The 5 identified protozoans were Entamoeba hartmani, E. coli, Endolimax nana, Giardia lamblia, and Blastocystis hominis, and the infection rate of E. nana was the highest (χ2 = 23.842, P < 0.05). Among the 8 counties (cities), the highest infection rate of helminthes, mainly with Enterobius infection, existed in Ruyang County, and the infection rate of protozoans in Xin'an County was the highest, mainly with E. nana infection. There was a significant difference in the infection rates of helminthes and protozoans among the 8 counties (cities) (helminthes: χ2 = 357.525, P < 0.05; protozoans: χ2 = 38.795, P < 0.05). There was no significant difference in the helminth infection rate between males and females ( χ2 = 0.034, P > 0.05), but the protozoan infection rate of the males was higher than that of the females ( χ2 = 12.946, P < 0.05). The helminth infection rate of the 0-9 years old group was the highest ( χ2 = 62.600, P < 0.05), up to 6.60%, mainly with E. vermicularis infection. There was no significant difference in the infection rate of intestinal parasites among nationalities ( χ2 = 0.212, P > 0.05). The helminth infection rate of preschool children was the highest and up to 8.43%, mainly with E. vermicularis infection. The infection of A. lumbricoides was mainly happened among farmers, with the infection rate of 0.31%. There was a significant difference in the helminth infection rate among different occupations (χ2 = 84.333, P < 0.05). The intestinal parasites infection rate of the illiterate population was the highest and up to 7.63%, there was a significant difference among the populations with different educational levels (χ2 = 72.013, P < 0.05). The helminth infection rate of plain areas was higher than that of valley and hill ( χ2 = 11.690, P < 0.05). The helminth infection rate of people with low-income was the highest and up to 10.32% (χ2 = 244.999, P < 0.05). The protozoan infection rate of people with middle-income was the highest, who had the annual per capita net income of 6 000 to 7 999 Yuan ( χ2 = 24.749, P < 0.05). The helminth infection rate of people drinking well water was much higher than that of people drinking tap water (χ2 = 62.255, P < 0.05). The protozoan infection rate of people without insect repellent was higher than that of people with insect repellent (χ2 = 5.235, P < 0.05). CONCLUSIONS: The infection rates of human intestinal parasites in the ecological region of the Qinba Mountains in Henan Province have decreased sharply. E. vermicularis infection in children should be the main point of prevention and treatment of parasitic diseases in the future.


Assuntos
Enteropatias Parasitárias , Animais , Criança , Pré-Escolar , China/epidemiologia , Fezes/parasitologia , Feminino , Helmintíase/epidemiologia , Helmintíase/parasitologia , Helmintíase/prevenção & controle , Humanos , Lactente , Enteropatias Parasitárias/epidemiologia , Enteropatias Parasitárias/parasitologia , Enteropatias Parasitárias/prevenção & controle , Masculino , Prevalência , Fatores de Risco , Fatores Socioeconômicos
15.
Infect Dis Poverty ; 8(1): 47, 2019 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-31202273

RESUMO

BACKGROUND: Despite efforts to control neglected tropical diseases (NTDs), schistosomiasis and soil-transmitted helminthiases remain widely prevalent in sub-Saharan Africa. Recent data suggest that these infections are prevalent among preschool aged children (PSAC) in poor communities. Evidence of schistosomiasis and soil-transmitted helminths (STH) infection patterns and prevalence among PSAC is essential for effective treatment and control programmes. The aim of the study was to determine the prevalence, intensity and risk factors of schistosomiasis and STH infection among PSAC in the Ingwavuma area of uMkhanyakude District, South Africa. METHODS: A cross-sectional study was conducted among 1143 PSAC aged 1-5 years in 34 preschools and early childhood development (ECD) centres. Data on risk factors was collected using a semi-structured questionnaire. A Kruskal-Wallis test was used to compare the differences in infection intensity with age. Pearson Chi-square test and multivariate logistic regression were performed to assess the association between PSAC infection status, sociodemographic, household, water and sanitation variables and hygiene practices of PSAC and their caregivers. RESULTS: We observed a low prevalence of Schistosoma haematobium (1.0%) and S. mansoni (0.9%). The prevalence of Ascaris lumbricoides (18.3%) was high compared to Trichuris trichiura (1.2%), hookworms (1.6%) and Taenia (6.4%). The odds of schistosome infection were lowest among PSAC under younger (15-24 years) caregivers (0.1, 95% CI: 0.02-0.54) and those who used tap water (0.3, 95% CI: 0.09-0.78) for domestic purposes. Schistosome infection was however higher among PSAC who bathed in river water (17.4, 95% CI: 5.96-51.04). STH infection on the other hand was lowest among PSAC who did not play in soil (0.1, 95% CI: 0.51-0.28), were from households that used tap water for domestic purposes (0.5, 95% CI: 0.27-0.80) and PSAC under the care of younger (25-35 years) caregivers (0.3, 95% CI: 0.10-0.75). The risk of STH infection was highest among PSAC who did not wash their hands with soap (3.5, 95% CI: 1.04-11.67) and PSAC whose nails were not trimmed (3.6, 95% CI: 1.75-7.26). CONCLUSIONS: The findings show low prevalence and infection intensity of schistosomiasis and STH infection except A. lumbricoides among PSAC. Factors predicting schistosomiasis and STH infection among PSAC were related to caregivers' age, educational status, water and hygiene practices. STH infection was exclusively associated with PSAC playing and handwashing habits. These findings highlight the need to include PSAC caregivers in schistosomiasis and STH prevention and control programmes.


Assuntos
População Rural/estatística & dados numéricos , Esquistossomose/epidemiologia , Solo/parasitologia , Pré-Escolar , Estudos Transversais , Feminino , Helmintíase/epidemiologia , Helmintíase/parasitologia , Humanos , Lactente , Masculino , Prevalência , Fatores de Risco , Esquistossomose/parasitologia , África do Sul/epidemiologia
16.
PLoS Negl Trop Dis ; 13(5): e0007372, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31150389

RESUMO

Soil-transmitted helminths (STHs) affect more than 1.5 billion people. The global strategy to control STH infections requires periodic mass drug administration (MDA) based on prevalence among populations at risk determined by diagnostic testing. Widely used copromicroscopy methods to detect infection, however, have low sensitivity as the prevalence and intensity of STH infections decline with repeated MDA. More sensitive diagnostic tools are needed to inform program decision-making. Using an integrated product development process, PATH conducted qualitative and quantitative formative research to inform the design and development of a more sensitive test for STH infections. The research, grounded in a conceptual framework for ensuring access to health products, involved stakeholder analysis, key opinion leader interviews, observational site visits of ongoing STH surveillance programs, and market research including market sizing, costing and willingness-to-pay analyses. Stakeholder analysis identified key groups and proposed strategic engagement of stakeholders during product development. Interviews highlighted features, motivations and concerns that are important for guiding design and implementation of new STH diagnostics. Process mapping outlined current STH surveillance workflows in Kenya and the Philippines. Market sizing in 2016 was estimated around half a million tests for lower STH burden countries, and 1-2 million tests for higher STH burden countries. The cost of commodities per patient for a molecular STH diagnostic may be around $10, 3-4 times higher than copromicroscopy methods, though savings may be possible in time and staffing requirements. The market is highly price sensitive as even at $5 per test, only 27% of respondents thought the test would be used by surveillance programs. A largely subsidized STH control strategy and a semi-functional Kato-Katz test may have created few incentives for manufacturers to innovate in STH diagnostics. Diverse partnerships, as well as balancing needs and expectations for new STH diagnostics are necessary to ensure access to needed products.


Assuntos
Testes Diagnósticos de Rotina/tendências , Helmintíase/diagnóstico , Animais , Pesquisa Biomédica/economia , Pesquisa Biomédica/tendências , Testes Diagnósticos de Rotina/economia , Testes Diagnósticos de Rotina/métodos , Fezes/parasitologia , Helmintíase/economia , Helmintíase/parasitologia , Helmintos/fisiologia , Humanos , Quênia , Laboratórios/economia , Laboratórios/tendências , Filipinas , Solo/parasitologia
17.
Korean J Parasitol ; 57(2): 135-144, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31104405

RESUMO

There have been some reports on schistosomiasis of school children in Sudan's Nile River basin area; however, information about the infection status of Schistosoma species and intestinal helminths among village residents of this area is very limited. Urine and stool samples were collected from the 1,138 residents of the Al Hidaib and Khour Ajwal villages of White Nile State, Sudan in 2014. The prevalence of overall schistosomiasis and intestinal helminthiasis was 36.3% and 7.7%, respectively. Egg positive rates were 35.6% for Schistosoma haematobium, 2.6% for S. mansoni, and 1.4% were mixed. The prevalence of schistosomiasis was significantly higher in men (45.6%) than in women (32.0%), in Khou Ajwal villagers (39.4%) than in Al Hidaib villagers (19.2%), and for age groups ≤15 years old (51.5%) than for age groups >15 years old (13.2%). The average number of eggs per 10 ml urine (EP10) of S. haematobium infections was 18.9, with 22.2 eggs in men vs 17.0 in women and 20.4 in Khou Ajwal villagers vs 8.1 in Al Hidaib villagers. In addition to S. mansoni eggs, 4 different species of intestinal helminths were found in the stool, including Hymenolepis nana (6.6%) and H. diminuta (1.0%). Collectively, urinary schistosomiasis is still prevalent among village residents in Sudan's White Nile River basin and was especially high in men, children ≤15 years, and in the village without a clean water system. H. nana was the most frequently detected intestinal helminths in the 2 villages.


Assuntos
Helmintíase/epidemiologia , Enteropatias Parasitárias/epidemiologia , Esquistossomose/epidemiologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Animais , Criança , Pré-Escolar , Coinfecção/epidemiologia , Coinfecção/parasitologia , Estudos Epidemiológicos , Fezes/parasitologia , Feminino , Helmintíase/parasitologia , Humanos , Hymenolepis diminuta/isolamento & purificação , Hymenolepis nana/isolamento & purificação , Lactente , Recém-Nascido , Enteropatias Parasitárias/parasitologia , Masculino , Pessoa de Meia-Idade , Contagem de Ovos de Parasitas , Prevalência , População Rural , Schistosoma haematobium/isolamento & purificação , Schistosoma mansoni/isolamento & purificação , Esquistossomose/parasitologia , Fatores Sexuais , Sudão/epidemiologia , Urina/parasitologia , Adulto Jovem
18.
Vet Parasitol ; 270 Suppl 1: S38-S44, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31104940

RESUMO

The efficacy and safety of a new topical formulation containing selamectin plus sarolaner (Revolution® Plus / Stronghold® Plus, Zoetis) was evaluated for the prevention of heartworm (Dirofilaria immitis) disease and the treatment of roundworm infection in cats enrolled as veterinary patients in two field studies conducted in Japan. In the heartworm field study, 91 cats negative for D. immitis antigen and anti-D. immitis antibody were enrolled and received 9 monthly topical treatments with selamectin plus sarolaner during the period of April to December 2015. Efficacy was assessed by testing post-treatment blood samples collected 8, 12, and 15 months after initiation of treatment for the presence of D. immitis antigen and anti-D. immitis antibody. Eighty-seven cats completed the entire study and were included in the determination of efficacy. No D. immitis antigen or anti-D. immitis antibody were detected in any of the post-treatment samples. In the roundworm field study, completed in the period from April to November 2015, 64 cats with ≥100 roundworm eggs per gram (EPG) of feces were enrolled and allocated randomly in a 1:1 ratio, to receive either selamectin plus sarolaner or emodepside plus praziquantel (Profender®, Bayer). Treatments were administered topically on Days 0 and 30, and efficacy was assessed by fecal EPG counts conducted on Days 14, 30, and 60. All cats completed the entire study. At enrollment, all cats were infected with Toxocara cati. Compared to pre-treatment, geometric mean T. cati EPG counts on Days 14, 30, and 60 were reduced by >99.9% in both treatment groups. There were no treatment-related adverse events in either study. Monthly topical administration of Revolution® Plus / Stronghold® Plus providing a minimum of 6 mg/kg selamectin and 1 mg/kg sarolaner was safe and effective in the prevention of heartworm disease and the treatment of roundworm infection in cats enrolled as veterinary patients in Japan.


Assuntos
Antiparasitários/administração & dosagem , Azetidinas/administração & dosagem , Doenças do Gato/prevenção & controle , Dirofilariose/prevenção & controle , Enteropatias Parasitárias/veterinária , Ivermectina/análogos & derivados , Infecções por Nematoides/veterinária , Compostos de Espiro/administração & dosagem , Administração Tópica , Animais , Doenças do Gato/tratamento farmacológico , Doenças do Gato/parasitologia , Gatos , Dirofilaria immitis/efeitos dos fármacos , Dirofilaria immitis/imunologia , Dirofilariose/tratamento farmacológico , Dirofilariose/parasitologia , Composição de Medicamentos/veterinária , Feminino , Helmintíase/tratamento farmacológico , Helmintíase/parasitologia , Helmintíase/prevenção & controle , Enteropatias Parasitárias/tratamento farmacológico , Enteropatias Parasitárias/parasitologia , Enteropatias Parasitárias/prevenção & controle , Ivermectina/administração & dosagem , Masculino , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/parasitologia , Infecções por Nematoides/prevenção & controle , Contagem de Ovos de Parasitas/veterinária , Distribuição Aleatória , Toxocara/efeitos dos fármacos , Resultado do Tratamento
19.
Malawi Med J ; 31(1): 12-18, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-31143391

RESUMO

Introduction: In Malawi, EcoSan sludge from ecological sanitation (EcoSan) latrines has been found to contain helminths, Salmonella and E. coli above WHO recommended levels making sludge unsuitable for direct handling and use on food crops. This research investigated survival of pathogens in EcoSan sludge with time after sealing the pit. Method: An observational longitudinal follow-up study was conducted where EcoSan latrines were followed from August 2015 to July 2016 in Blantyre and Chikwawa in Southern Malawi. The study enrolled 51 latrines in total with 35 latrines [13 fossa alterna (FAs) and 22 urine diverting dry latrines (UDDLs)] remaining at the end of study. Samples were collected five times from each latrine and examined for helminths, Salmonella and E. coli in the laboratory. Poisson regression was employed to assess factors that significantly contribute to pathogen die off at p<0.05. Results: Average concentrations of all pathogens investigated reduced over 12-month follow-up period except for Salmonella which increased. A. lumbricoides, increased to 2.3 viable eggs during the second sampling and decreased to 0.4 viable eggs per gram after 12 months of follow-up. Time was the only consistent predictor for concentration of helminths. Type of latrine and location were not significant predictors of helminths concentration (p>0.05). However, Salmonella and E. coli colonies were significantly higher in UDDLs (Blantyre) than FAs (Chikwawa) (p<0.05). Conclusion: Pathogen concentration was highest after recommended six months of storage posing a public health risk to those handling and using it for agriculture purposes. It is therefore recommended that the current guidelines be reviewed to suit Malawi context. A storage period of one year or more is recommended.


Assuntos
Infecções por Escherichia coli/epidemiologia , Helmintíase/epidemiologia , Saúde Pública , Saneamento/métodos , Esgotos/análise , Toaletes/estatística & dados numéricos , Animais , Escherichia coli/fisiologia , Infecções por Escherichia coli/microbiologia , Seguimentos , Helmintíase/parasitologia , Helmintos/fisiologia , Humanos , Estudos Longitudinais , Malaui/epidemiologia
20.
Artigo em Inglês | MEDLINE | ID: mdl-31125837

RESUMO

Anthelmintic resistance is a threat to global food security. In order to alleviate the selection pressure for resistance and maintain drug efficacy, management strategies increasingly aim to preserve a proportion of the parasite population in 'refugia', unexposed to treatment. While persuasive in its logic, and widely advocated as best practice, evidence for the ability of refugia-based approaches to slow the development of drug resistance in parasitic helminths is currently limited. Moreover, the conditions needed for refugia to work, or how transferable those are between parasite-host systems, are not known. This review, born of an international workshop, seeks to deconstruct the concept of refugia and examine its assumptions and applicability in different situations. We conclude that factors potentially important to refugia, such as the fitness cost of drug resistance, the degree of mixing between parasite sub-populations selected through treatment or not, and the impact of parasite life-history, genetics and environment on the population dynamics of resistance, vary widely between systems. The success of attempts to generate refugia to limit anthelmintic drug resistance are therefore likely to be highly dependent on the system in hand. Additional research is needed on the concept of refugia and the underlying principles for its application across systems, as well as empirical studies within systems that prove and optimise its usefulness.


Assuntos
Anti-Helmínticos/farmacologia , Resistência a Medicamentos , Helmintos/efeitos dos fármacos , Animais , Helmintíase/parasitologia , Helmintos/genética , Helmintos/crescimento & desenvolvimento , Humanos , Refúgio
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