Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 56
Filtrar
1.
BMC Infect Dis ; 21(1): 91, 2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33478414

RESUMO

BACKGROUND: Informed decision making is underlined by all tiers in the health system. Poor data record system coupled with under- (over)-reporting of malaria cases affects the country's malaria elimination activities. Thus, malaria data at health facilities and health offices are important particularly to monitor and evaluate the elimination progresses. This study was intended to assess overall reported malaria cases, reporting quality, spatiotemporal trends and factors associated in Gedeo zone, South Ethiopia. METHODS: Past 8 years retrospective data stored in 17 health centers and 5 district health offices in Gedeo Zone, South Ethiopia were extracted. Malaria cases data at each health center with sociodemographic information, between January 2012 and December 2019, were included. Meteorological data were obtained from the national meteorology agency of Ethiopia. The data were analyzed using Stata 13. RESULTS: A total of 485,414 suspected cases were examined for malaria during the previous 8 years at health centers. Of these suspects, 57,228 (11.79%) were confirmed malaria cases with an overall decline during the 8-year period. We noted that 3758 suspected cases and 467 confirmed malaria cases were not captured at the health offices. Based on the health centers records, the proportions of Plasmodium falciparum (49.74%) and P. vivax (47.59%) infection were nearly equivalent (p = 0.795). The former was higher at low altitudes while the latter was higher at higher altitudes. The over 15 years of age group accounted for 11.47% of confirmed malaria cases (p < 0.001). There was high spatiotemporal variation: the highest case record was during Belg (12.52%) and in Dilla town (18,150, 13.17%, p < 0.001) which is located at low altitude. Monthly rainfall and minimum temperature exhibited strong associations with confirmed malaria cases. CONCLUSION: A notable overall decline in malaria cases was observed during the eight-year period. Both P. falciparum and P. vivax were found at equivalent endemicity level; hence control measures should continue targeting both species. The noticed under reporting, the high malaria burden in urban settings, low altitudes and Belg season need spatiotemporal consideration by the elimination program.


Assuntos
Malária/epidemiologia , Altitude , Demografia , Notificação de Doenças/normas , Notificação de Doenças/estatística & dados numéricos , Etiópia/epidemiologia , Feminino , Humanos , Malária/diagnóstico , Malária/parasitologia , Malária/prevenção & controle , Masculino , Meteorologia , Análise Multivariada , Plasmodium falciparum/isolamento & purificação , Plasmodium vivax/isolamento & purificação , Prevalência , Estudos Retrospectivos , Estações do Ano
2.
Parasit Vectors ; 14(1): 39, 2021 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-33430946

RESUMO

BACKGROUND: The Benishangul-Gumuz region is an important development corridor in Ethiopia. Large-scale projects such as the Great Renaissance Dam, mining and agriculture have entailed huge environmental modifications and settlement pattern changes. There is no detailed epidemiological information on visceral leishmaniasis (VL) in the region. MATERIALS AND METHODS: A cross-sectional study was carried out to assess the epidemiology and risk factors associated with Leishmania infection. A leishmanin skin test (LST) was done for 1342 participants, and for 253 of them rK39 and DAT were carried out. Thirty-six dogs owned by households with LST-positive member(s) were rK39 and DAT tested. A pretested questionnaire was used to capture individual and household characteristics. RESULTS: Of the 89.2% (1197/1342) who availed themselves of the LST reading, 6.0% were positive. The rk39 and DAT positivity among the 253 tested were 3.2% and 5.9%, respectively. In dogs, positivity rates by rK39 and DAT were 13.9% and 5.6%, respectively. Of the household and individual risk factors, presence of a dog in the household (P = 0.005), male sex (0.003), residence woreda (0.000) and occupation (0.023) showed a strong positive association with LST positivity. Individuals who lived in households that had dogs were 2.6 times more likely to be LST positive (AOR = 2.6; 95% CI = 1.54, 4.40). Being female decreased the probability of being LST positive by 0.38 times (AOR = 0.38; 95% CI = 0.20, 0.72). People living in Guba and Kurmuk had 4.7 (AOR = 4.74, 95% CI 1.83, 12.31) and 5.9 (AOR = 5.85, 95% CI 2.27, 15.09) times more risk of being infected. CONCLUSIONS: We demonstrated the presence of active VL transmission in the areas. Thus, we underline the need to establish the responsible vector(s) and reservoir(s) for comprehensive early containment plans to prevent potentially harmful public health and economic consequences.

3.
Emerg Infect Dis ; 27(2): 603-607, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33496217

RESUMO

Anopheles stephensi mosquitoes, efficient vectors in parts of Asia and Africa, were found in 75.3% of water sources surveyed and contributed to 80.9% of wild-caught Anopheles mosquitoes in Awash Sebat Kilo, Ethiopia. High susceptibility of these mosquitoes to Plasmodium falciparum and vivax infection presents a challenge for malaria control in the Horn of Africa.

4.
Malar J ; 20(1): 59, 2021 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33482841

RESUMO

BACKGROUND: As countries move to malaria elimination, detecting and targeting asymptomatic malaria infections might be needed. Here, the epidemiology and detectability of asymptomatic Plasmodium falciparum and Plasmodium vivax infections were investigated in different transmission settings in Ethiopia. METHOD: A total of 1093 dried blood spot (DBS) samples were collected from afebrile and apparently healthy individuals across ten study sites in Ethiopia from 2016 to 2020. Of these, 862 were from community and 231 from school based cross-sectional surveys. Malaria infection status was determined by microscopy or rapid diagnostics tests (RDT) and 18S rRNA-based nested PCR (nPCR). The annual parasite index (API) was used to classify endemicity as low (API > 0 and < 5), moderate (API ≥ 5 and < 100) and high transmission (API ≥ 100) and detectability of infections was assessed in these settings. RESULTS: In community surveys, the overall prevalence of asymptomatic Plasmodium infections by microscopy/RDT, nPCR and all methods combined was 12.2% (105/860), 21.6% (183/846) and 24.1% (208/862), respectively. The proportion of nPCR positive infections that was detectable by microscopy/RDT was 48.7% (73/150) for P. falciparum and 4.6% (2/44) for P. vivax. Compared to low transmission settings, the likelihood of detecting infections by microscopy/RDT was increased in moderate (Adjusted odds ratio [AOR]: 3.4; 95% confidence interval [95% CI] 1.6-7.2, P = 0.002) and high endemic settings (AOR = 5.1; 95% CI 2.6-9.9, P < 0.001). After adjustment for site and correlation between observations from the same survey, the likelihood of detecting asymptomatic infections by microscopy/RDT (AOR per year increase = 0.95, 95% CI 0.9-1.0, P = 0.013) declined with age. CONCLUSIONS: Conventional diagnostics missed nearly half of the asymptomatic Plasmodium reservoir detected by nPCR. The detectability of infections was particularly low in older age groups and low transmission settings. These findings highlight the need for sensitive diagnostic tools to detect the entire parasite reservoir and potential infection transmitters.

5.
Int J Infect Dis ; 104: 183-188, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33373719

RESUMO

BACKGROUND: Chikungunya virus (CHIKV) infection has similar clinical presentations to malaria. Hence, febrile illnesses are often misdiagnosed as malaria. Therefore, this study aimed to generate baseline data on CHIKV infection in northwest Ethiopia where malaria is endemic. METHODS: A hospital-based cross-sectional study was conducted among febrile patients presenting at the Metema and Humera Kahsay Abera hospitals from March 2016 to May 2017. Data on socio-demographic, clinical presentations, and possible risk factors were collected using a structured questionnaire. Serum samples were screened for immunoglobulin-M (IgM) and IgG antibodies to CHIKV infections using enzyme-linked immunosorbent assay. Logistic regression analysis was used to determine the strength of association. RESULTS: Of 586 samples screened, the overall seroprevalence of CHIKV infection was 23%. Of the total study participants, 22.5% had CHIKV-specific IgM, indicating recent CHIKV infection. During monsoon and post-monsoon periods, increased prevalence of anti-CHIKV IgM seropositivity was found. The most common clinical presentation observed was fever, followed by headache and joint pain. Men had twice the likelihood of CHIKV infection. The presence of stagnant water near the residence almost doubled the risk for CHIKV infection. CONCLUSIONS: Most of the study participants had recent infection with CHIKV, suggesting the need to design disease prevention and intervention strategies.

6.
BMC Complement Med Ther ; 20(1): 366, 2020 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-33238963

RESUMO

BACKGROUND: The incidence and mortality of breast cancer in women is increasing worldwide. Breast cancer contains a subpopulation of cells known as cancer stem cells (CSCs). The CSCs are believed to be responsible for chemotherapeutic resistance and are also involved in tumor initiation, progression, evolution, and metastasis to distant sites. The present study aimed to investigate the anti-CSC potential of selected Ethiopian medicinal plants traditionally used for breast cancer treatment. METHODS: The solvent fractions of three medicinal plants (the ethyl acetate fraction of Vernonia leopoldi, the aqueous fraction of Sideroxylon oxyacanthum, and the chloroform fraction of Clematis simensis) resulting from the methanolic crude extracts were selected based on their previously demonstrated cytotoxic effects on breast cancer cell lines. The effect of these solvent fractions on the status of the cancer stem cell subpopulation of the JIMT-1 cell line was assessed by flow cytometric evaluation of the proportion of aldehyde dehydrogenase positive cells and by measuring colony forming efficiency in a serum-free soft agar assay after treatment. Effects on cell migration using a wound healing assay and on tumor necrosis factor-α-induced translocation of nuclear factor-kappa B to the cell nucleus were also investigated. RESULTS: The solvent fractions showed a dose-dependent reduction in the aldehyde dehydrogenase positive subpopulation of JIMT-1 cells. The chloroform fraction of C. simensis (80 µg/mL) completely blocked colony formation of JIMT-1 cells. The wound healing assay showed that all fractions significantly reduced cell migration. The ethyl acetate fraction of V. leopoldi (0.87 µg/mL) significantly inhibited tumor necrosis factor-α-induced nuclear factor-kappa B translocation to the nucleus. CONCLUSION: The solvent fractions of the medicinal plants showed desirable activities against breast cancer stem cells in the JIMT-1 cell line, which warrants further studies.

7.
Sci Rep ; 10(1): 19975, 2020 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-33203956

RESUMO

The distribution of malaria infections is heterogeneous in space and time, especially in low transmission settings. Understanding this clustering may allow identification and targeting of pockets of transmission. In Adama district, Ethiopia, Plasmodium falciparum and P. vivax malaria patients and controls were examined, together with household members and immediate neighbors. Rapid diagnostic test and quantitative PCR (qPCR) were used for the detection of infections that were genetically characterized by a panel of microsatellite loci for P. falciparum (26) and P. vivax (11), respectively. Individuals living in households of clinical P. falciparum patients were more likely to have qPCR detected P. falciparum infections (22.0%, 9/41) compared to individuals in control households (8.7%, 37/426; odds ratio, 2.9; 95% confidence interval, 1.3-6.4; P = .007). Genetically related P. falciparum, but not P. vivax infections showed strong clustering within households. Genotyping revealed a marked temporal cluster of P. falciparum infections, almost exclusively comprised of clinical cases. These findings uncover previously unappreciated transmission dynamics and support a rational approach to reactive case detection strategies for P. falciparum in Ethiopia.

8.
BMC Infect Dis ; 20(1): 639, 2020 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-32867694

RESUMO

BACKGROUND: Dengue fever is an arthropod vector-borne disease transmitted to humans by infected Aedes mosquitoes. Ethiopia has a favorable ecology for arthropods and report high burden of acute febrile illnesses. However, the contribution of arboviral infections to the burden of acute febrile illnesses is barely known. In this study the seropositivity to dengue virus infection and associated risk factors were assessed in Arba Minch districts, southern Ethiopia. METHODS: An institution based cross-sectional study was conducted in a consecutive group of 529 acute febrile patients between May to August 2016. Socio-demographic data, residence place and clinical signs and symptoms were collected using structured questionnaires. Sera were tested for anti-dengue IgG and IgM using Euroimmune indirect immunofluorescent assay. Data analysis was done using SPSS V-20 (IBM Corp, 2012). P-value < 0.05 was taken as statistically significant. RESULT: Seropositivity was 25.1% (133/529) and 8.1% (43/529) for anti- IgG and IgM respectively. CONCLUSION: The high IgM prevalence detected indicate the probability of active transmission with a potential of public health significance that calls for a proactive follow up of the communities in the study area to forecast and avert the risk.


Assuntos
Anticorpos Antivirais/sangue , Vírus da Dengue/imunologia , Dengue/sangue , Dengue/epidemiologia , Febre/sangue , Febre/epidemiologia , Adolescente , Adulto , Animais , Estudos Transversais , Dengue/diagnóstico , Dengue/virologia , Etiópia/epidemiologia , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Inquéritos e Questionários , Adulto Jovem
9.
Cytokine ; : 155289, 2020 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-32951968

RESUMO

The clinical course and outcome of cutaneous leishmaniasis (CL) vary due to the infecting Leishmania species and host genetic makeup that result in different immune responses against the parasites. The host immune response to Leishmania aethiopica (L.aethiopica), the causative agent of CL in Ethiopia, is poorly understood. To contribute to the understanding of the protective immune response in CL due to L.aethiopica, we characterized the cytokine response to L. aethiopica in patients with the localized form of CL (LCL) and age-and sex-matched apparently healthy controls. By applying a whole blood based in vitro culture we found enhanced release of TNF, IL-6, MCP-1 or CCL2, IP-10 or CXCL10, MIP-1ß or CCL4 and IL-8 or CXCL8- but not of IL-10CL patients in response to L. aethiopica compared to the controls. No difference was observed between LCL cases and controls in the secretion of these cytokines and chemokines in whole blood cultures treated with the TLR-ligands LPS, MALP-2 or polyI: C. The observed increased secretion of the pro-inflammatory cytokines/chemokines reflects an enhanced response against the parasites by LCL patients as compared to healthy controls rather than a generally enhanced ability of blood leukocytes from LCL patients to respond to microbial constituents. Our findings suggest that the enhanced production of pro-inflammatory cytokines/chemokines is associated with localized cutaneous leishmaniasis caused by L.aethiopica.

10.
PLoS Negl Trop Dis ; 14(8): e0008507, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32841279

RESUMO

BACKGROUND: Cutaneous leishmaniasis is one of the most neglected tropical diseases increasing in its public health importance. In Ethiopia over 28 million people are living at risk of infection. METHOD: Institution based cross-sectional study was conducted at Borumeda Hospital from February to May 2019. A total 205 leishmaniasis suspected patients were included by systematic random sampling technique. Socio demographic characteristics were collected using pre-tested questionnaires. Parasitological investigation was done from skin slit sample by using Geimsa staining method. Species identification was done by PCR-RFLP. Data were entered in to EpiData version 3.1 and analyzed using SPSS version 20 software. P-value of ≤ 0.05 was considered as statistically significant. RESULT: A total of 205 participants consisting 59% male and 41% female included in this study. The mean age (±SD) of the study participants was 31.9 (±14.29). The overall prevalence of cutaneous leishmaniasis was 22.4% (46/205). The prevalence in males (13.7%) was higher than in females (8.8%). It was more prevalent in the age group 16-45years old (15.6%). Clinically, 60% of patients' hade single lesion with 1.55 average number of lesions. About 30.7% of patients' had indurated plaque type of lesion. Most of the lesions were found on head and face (59%). House near to farmland, presence of hyrax in the village and presence of other cutaneous leishmaniasis cases in the neighborhood were independent predicator of cutaneous leishmaniasis prevalence. L.aethopica was found to be the etiologic agent of cutaneous leishmaniasis in the study participants. CONCLUSION: The prevalence of cutaneous leishmaniasis was 22.4%, this alerts the need of intervention. It is statistically associated with house near to farm land, presence of other cutaneous leishmaniasis cases in the neighborhood and presence of hyrax in village. Head and face were the most common sites of lesion.


Assuntos
Leishmania/genética , Leishmania/isolamento & purificação , Leishmaniose Cutânea/epidemiologia , Leishmaniose Cutânea/parasitologia , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Estudos Transversais , DNA de Protozoário/análise , Etiópia/epidemiologia , Feminino , Humanos , Leishmaniose Cutânea/diagnóstico , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Prevalência , Adulto Jovem
11.
Cytokine ; : 155246, 2020 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-32828639

RESUMO

The likelihood of being bitten by sand flies infected with Leishmania (L.) donovani is considered to be high for all inhabitants living in the endemic areas, but only a small ratio of the population develop symptomatic visceral leishmanisis (VL). Since adequate activation of antimicrobial immune response plays a key role in control of pathogens early after infection we hypothesized that a dysfunction of essential cells of the immune system is associated with disease development after infection with L. donovani. In order to obtain insights into the capacity of leukocytes to respond to L. donovani, a whole blood based assay was applied to evaluate the production of cytokines and chemokines in clinical VL versus Ethiopian endemic healthy control (EHC). In response to L. donovani, VL blood cultures showed significantly lower secretion of IL-12p70, IL-6, IL-17, IL-8 and IP-10 compared to EHC. On the contrary, there was a significantly higher secretion of IL-10 observed in VL compared to EHC. In response to LPS also a lower IL-1ß, IL-12p70 and IL-6 secretion was observed in VL as compared to EHC. The data clearly indicate a diminished ability of blood leukocytes in VL to respond to L. donovani and to the TLR ligand LPS. This compromised response in VL may contribute to the severe disease development and enhanced susceptibility to secondary infections in VL.

12.
BMC Microbiol ; 20(1): 90, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-32293265

RESUMO

BACKGROUND: Visceral leishmaniasis in Ethiopia is a re-emerging threat to public health, with increased geographical distribution and number of cases. It is a fatal disease without early diagnosis and treatment; thus, the availability of affordable diagnostic tools is crucial. However, due to delays caused by import regulations, procurement and late delivery of imported test kits, accessibility remains a problem in the control program. Therefore, we aimed to produce and evaluate the performance of an in-house liquid (AQ) direct agglutination test (DAT) antigen. RESULT: The AQ-DAT was produced at the Armauer Hansen Research Institute, using Leishmania donovani strain (MHOM/ET/67/L82). Sera from 272 participants; 110 microscopically confirmed cases of VL, 76 apparently healthy and 86 patients who had infectious disease other than VL were tested with AQ-DAT, and standard kits: Freeze-dried DAT (FD-DAT) and rK39. Taking microscopy as a gold standard; the sensitivity and specificity of the AQ-DAT were 97.3 and 98.8%, respectively. It had high degrees of agreement (k > 0.8), with a significant (P < 0.05) correlation compared to microscopy, FD-DAT, and rK39. CONCLUSION: Although further standardization is required, the in-house AQ-DAT could improve diagnostic accessibility, minimize intermittent stock outs and strengthen the national VL control program.

13.
Parasit Vectors ; 13(1): 120, 2020 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-32143713

RESUMO

BACKGROUND: Mosquito-feeding assays that assess transmission of Plasmodium from man-to-mosquito typically use laboratory mosquito colonies. The microbiome and genetic background of local mosquitoes may be different and influence Plasmodium transmission efficiency. In order to interpret transmission studies to the local epidemiology, it is therefore crucial to understand the relationship between infectivity in laboratory-adapted and local mosquitoes. METHODS: We assessed infectivity of Plasmodium vivax-infected patients from Adama, Ethiopia, using laboratory-adapted (colony) and wild-caught (wild) mosquitoes raised from larval collections in paired feeding experiments. Feeding assays used 4-6 day-old female Anopheles arabiensis mosquitoes after starvation for 12 h (colony) and 18 h (wild). Oocyst development was assessed microscopically 7 days post-feeding. Wild mosquitoes were identified morphologically and confirmed by genotyping. Asexual parasites and gametocytes were quantified in donor blood by microscopy. RESULTS: In 36 paired experiments (25 P. vivax infections and 11 co-infections with P. falciparum), feeding efficiency was higher in colony (median: 62.5%; interquartile range, IQR: 47.0-79.0%) compared to wild mosquitoes (median: 27.8%; IQR: 17.0-38.0%; Z = 5.02; P < 0.001). Plasmodium vivax from infectious individuals (51.6%, 16/31) infected a median of 55.0% (IQR: 6.7-85.7%; range: 5.5-96.7%; n = 14) of the colony and 52.7% (IQR: 20.0-80.0%; range: 3.2-95.0%; n = 14) of the wild mosquitoes. A strong association (ρ(16) = 0.819; P < 0.001) was observed between the proportion of infected wild and colony mosquitoes. A positive association was detected between microscopically detected gametocytes and the proportion of infected colony (ρ(31) = 0.452; P = 0.011) and wild (ρ(31) = 0.386; P = 0.032) mosquitoes. CONCLUSIONS: Infectivity assessments with colony and wild mosquitoes yielded similar infection results. This finding supports the use of colony mosquitoes for assessments of the infectious reservoir for malaria in this setting whilst acknowledging the importance of mosquito factors influencing sporogonic development of Plasmodium parasites.


Assuntos
Anopheles/fisiologia , Anopheles/parasitologia , Laboratórios , Malária Vivax/parasitologia , Mosquitos Vetores/fisiologia , Mosquitos Vetores/parasitologia , Plasmodium vivax/fisiologia , Animais , Etiópia , Comportamento Alimentar/fisiologia , Feminino , Interações Hospedeiro-Parasita , Humanos , Larva , Malária/transmissão , Oocistos/crescimento & desenvolvimento , Plasmodium vivax/genética
14.
Am J Trop Med Hyg ; 102(1): 117-120, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31733053

RESUMO

Ethiopia aims to diagnose and treat all clinical malaria within 24 hours of fever onset in its stride to eliminate the disease by 2030. Microscopy remains to be the mainstay for diagnosis at the health center and hospital level. Continuous evaluation and performance upgrading of malaria microscopists is one of the cornerstones in this effort. We assessed the performance of malaria microscopists compared with reference readers in diagnosing, identifying the species, and quantifying parasitemia. A total of 174 microscopists were enrolled from health facilities located in 86 districts in Oromia region (Ethiopia) from January 2017 to June 2018. Panel slides with known Plasmodium species, diagnostic blood stage, and parasite density were prepared by the reference readers. Sociodemographics, education, in-service training, and routine practice of participants were captured. Sensitivity, specificity, percent agreement, and kappa score were calculated. An overall low performance was observed that could threaten the malaria diagnostic service. Of all the slides distributed (1,218), only 17.0% of the positive and 30.0% of the negative slides were correctly identified and 22.4% were correctly quantified. Compared with the reference readers, participants had lower competence in diagnosing (74.3% agreement and kappa 0.45) and identifying the species (71.2% agreement and kappa 0.40). Two-fifths of the participants were graded as "in training" with respect to identifying the species (41.0%) and the diagnostic stages (40.0%). An in-service training/retraining and supportive supervision are needed to raise and maintain the competence of microscopists in settings with a recent decline in malaria transmission and aiming for ultimate elimination of the disease.


Assuntos
Pessoal de Laboratório/normas , Malária Falciparum/diagnóstico , Malária Vivax/diagnóstico , Microscopia/normas , Adulto , Técnicas de Laboratório Clínico/normas , Erros de Diagnóstico , Etiópia/epidemiologia , Feminino , Humanos , Malária Falciparum/epidemiologia , Malária Vivax/epidemiologia , Masculino , Sensibilidade e Especificidade
15.
Artigo em Inglês | MEDLINE | ID: mdl-31539706

RESUMO

Plasmodium falciparum and P. vivax co-exist at different endemicity levels across Ethiopia. For over two decades Artemether-Lumefantrine (AL) is the first line treatment for uncomplicated P. falciparum, while chloroquine (CQ) is still used to treat P. vivax. It is currently unclear whether a shift from CQ to AL for P. falciparum treatment has implications for AL efficacy and results in a reversal of mutations in genes associated to CQ resistance, given the high co-endemicity of the two species and the continued availability of CQ for the treatment of P. vivax. This study thus assessed the prevalence of Pfcrt-K76T and Pfmdr1-N86Y point mutations in P. falciparum. 18S RNA gene based nested PCR confirmed P. falciparum samples (N = 183) collected through community and health facility targeted cross-sectional surveys from settings with varying P. vivax and P. falciparum endemicity were used. The proportion of Plasmodium infections that were P. vivax was 62.2% in Adama, 41.4% in Babile, 30.0% in Benishangul-Gumuz to 6.9% in Gambella. The Pfcrt-76T mutant haplotype was observed more from samples with higher endemicity of P. vivax as being 98.4% (61/62), 100% (31/31), 65.2% (15/23) and 41.5% (22/53) in samples from Adama, Babile, Benishangul-Gumuz and Gambella, respectively. However, a relatively higher proportion of Pfmdr1-N86 allele (77.3-100%) were maintained in all sites. The observed high level of the mutant Pfcrt-76T allele in P. vivax co-endemic sites might require that utilization of CQ needs to be re-evaluated in settings co-endemic for the two species. A country-wide assessment is recommended to clarify the implication of the observed level of variation in drug resistance markers on the efficacy of AL-based treatment against uncomplicated P. falciparum malaria.


Assuntos
Proteínas de Membrana Transportadoras/genética , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Plasmodium falciparum/genética , Plasmodium vivax/genética , Proteínas de Protozoários/genética , Adolescente , Adulto , Alelos , Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Combinação Arteméter e Lumefantrina/farmacologia , Combinação Arteméter e Lumefantrina/uso terapêutico , Criança , Cloroquina/farmacologia , Cloroquina/uso terapêutico , Resistência a Medicamentos , Doenças Endêmicas , Etiópia/epidemiologia , Feminino , Haplótipos , Humanos , Malária Falciparum/complicações , Malária Falciparum/tratamento farmacológico , Malária Falciparum/epidemiologia , Malária Falciparum/parasitologia , Malária Vivax/complicações , Malária Vivax/tratamento farmacológico , Malária Vivax/epidemiologia , Malária Vivax/parasitologia , Masculino , Plasmodium falciparum/classificação , Plasmodium falciparum/fisiologia , Plasmodium vivax/classificação , Plasmodium vivax/fisiologia , Mutação Puntual , Polimorfismo Genético , Prevalência , Adulto Jovem
17.
Diagn Progn Res ; 3: 4, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31093574

RESUMO

Background: In addition to direct slide microscopy, traditional culture method (TCM) has long been considered as a gold standard method for the diagnosis of cutaneous leishmaniasis (CL). However, TCM is relatively expensive and time-consuming compared to the newly introduced microculture method (MCM), which has shown to be sensitive and rapid diagnostic method elsewhere for different Leishmania parasite species other than Leishmania (L.) aethiopica. The objective of this study was to evaluate the diagnostic performance of MCM for the diagnosis of CL caused by L. aethiopica. Methods: One hundred forty-three lesion aspirates were collected from 124 suspected CL patients prospectively based on their consecutive series. Portion of the aspirates were cultured in duplicate in TCM with modified Novy-MacNeal-Nicolle (NNN) in tissue culture flask and microcapillary tubes containing RPMI 1640 with 10% fetal bovine serum (FBS) for MCM. Smears on glass slides from the remaining portion of the aspirate were used for direct microscopy to detect the parasite after stained with Giemsa staining solution. Up on a consensus, positive result in any two of the three tests was used as a reference standard to analyze sensitivity. Results: As per consensus standard criteria, 52 of the lesions were qualified to evaluate MCM versus TCM. Forty-eight lesion samples were positive by MCM, 36 by TCM, and 37 by smear microscopy. The representative DNA from parasite culture isolates revealed the causative Leishmania parasite was L. aethiopica by ITS1 polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Culturing L. aethiopica in vitro by MCM is more sensitive (92.3%) than by TCM (69.2%), P = 0.003. The median time for L. aethiopica promastigotes emergence in the culture was 3 days for MCM and 6 days for TCM, P < 0.001. Conclusions: Our finding indicated that MCM is a sensitive and a rapid culturing method for the isolation of L. aethiopica than TCM and smear microscopy.

18.
Nat Commun ; 10(1): 1433, 2019 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-30926893

RESUMO

Malaria infections occurring below the limit of detection of standard diagnostics are common in all endemic settings. However, key questions remain surrounding their contribution to sustaining transmission and whether they need to be detected and targeted to achieve malaria elimination. In this study we analyse a range of malaria datasets to quantify the density, detectability, course of infection and infectiousness of subpatent infections. Asymptomatically infected individuals have lower parasite densities on average in low transmission settings compared to individuals in higher transmission settings. In cohort studies, subpatent infections are found to be predictive of future periods of patent infection and in membrane feeding studies, individuals infected with subpatent asexual parasite densities are found to be approximately a third as infectious to mosquitoes as individuals with patent (asexual parasite) infection. These results indicate that subpatent infections contribute to the infectious reservoir, may be long lasting, and require more sensitive diagnostics to detect them in lower transmission settings.


Assuntos
Malária Falciparum/epidemiologia , Malária Falciparum/parasitologia , Parasitos/fisiologia , Plasmodium falciparum/fisiologia , Animais , Células Germinativas/metabolismo , Humanos , Parasitemia/parasitologia , Probabilidade , Fatores de Tempo
19.
Trans R Soc Trop Med Hyg ; 113(6): 305-311, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-30927007

RESUMO

BACKGROUND: Following successful malaria control during the last decade, Ethiopia instituted a stepwise malaria elimination strategy in selected low-transmission areas. METHODS: Cross-sectional surveys were conducted in Babile district, Oromia, Ethiopia from July to November 2017 to evaluate malaria infection status using microscopy and nested polymerase chain reaction (nPCR) and serological markers of exposure targeting Plasmodium falciparum and Plasmodium vivax apical membrane antigen-1 (AMA-1). RESULTS: Parasite prevalence was 1.2% (14/1135) and 5.1% (58/1143) for P. falciparum and 0.4% (5/1135) and 3.6% (41/1143) for P. vivax by microscopy and nPCR, respectively. Antibody prevalence was associated with current infection by nPCR for both P. falciparum (p<0.001) and P. vivax (p=0.014) and showed an age-dependent increase (p<0.001, for both species). Seroconversion curves indicated a decline in malaria exposure 15 y prior to sampling for P. falciparum and 11.5 y prior to sampling for P. vivax, broadly following malaria incidence data from district health offices, with higher antibody titres in adults than children for both species. CONCLUSIONS: Malaria transmission declined substantially in the region with continuing heterogeneous but measurable local transmission, arguing in favour of continued and tailored control efforts to accelerate the progress towards elimination efforts.


Assuntos
Malária Falciparum/epidemiologia , Malária Vivax/epidemiologia , Adolescente , Adulto , Criança , Pré-Escolar , Estudos Transversais , Etiópia/epidemiologia , Feminino , Humanos , Malária Falciparum/transmissão , Malária Vivax/transmissão , Masculino , Pessoa de Meia-Idade , Plasmodium falciparum/isolamento & purificação , Plasmodium vivax/isolamento & purificação , Prevalência , Estudos Soroepidemiológicos , Adulto Jovem
20.
BMC Struct Biol ; 19(1): 6, 2019 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-30917807

RESUMO

BACKGROUND: Plasmodium vivax merozoite surface protein 3α (PvMSP3α) is a promising vaccine candidate which has shown strong association with immunogenicity and protectiveness. Its use is however complicated by evolutionary plasticity features which enhance immune evasion. Low complexity regions (LCRs) provide plasticity in surface proteins of Plasmodium species, but its implication in vaccine design remain unexplored. Here population genetic, comparative phylogenetic and structural biology analysis was performed on the gene encoding PvMSP3α. RESULTS: Three LCRs were found in PvMSP3α block II. Both the predicted tertiary structure of the protein and the phylogenetic trees based on this region were influenced by the presence of the LCRs. The LCRs were mainly B cell epitopes within or adjacent. In addition a repeat motif mimicking one of the B cell epitopes was found within the PvMSP3a block II low complexity region. This particular B cell epitope also featured rampant alanine substitutions which might impair antibody binding. CONCLUSION: The findings indicate that PvMSP3α block II possesses LCRs which might confer a strong phenotypic plasticity. The phenomenon of phenotypic plasticity and implication of LCRs in malaria immunology in general and vaccine candidate genes in particular merits further exploration.


Assuntos
Antígenos de Protozoários/química , Antígenos de Protozoários/imunologia , Malária Vivax/imunologia , Plasmodium vivax/isolamento & purificação , Proteínas de Protozoários/química , Proteínas de Protozoários/imunologia , Substituição de Aminoácidos , Antígenos de Protozoários/genética , Epitopos de Linfócito B/metabolismo , Etiópia , Humanos , Evasão da Resposta Imune , Malária Vivax/parasitologia , Modelos Moleculares , Filogenia , Plasmodium vivax/imunologia , Plasmodium vivax/metabolismo , Polimorfismo Genético , Domínios Proteicos , Estrutura Terciária de Proteína , Proteínas de Protozoários/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...