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1.
Malar J ; 22(1): 273, 2023 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-37710252

RESUMEN

BACKGROUND: Plasmodium falciparum and Plasmodium vivax are coendemic in Ethiopia, with different proportion in different settings. Microscopy is the diagnostic tool in Ethiopian health centres. Accurate species-specific diagnosis is vital for appropriate treatment of cases to interrupt its transmission. Therefore, this study assessed the status of species-specific misdiagnosis by microscope compared with polymerase chain reaction (PCR). METHODS: A health facility based cross-sectional study was conducted from November 2019 to January 2020 in Kolla Shelle Health centre, Arba Minch Zuria district. The study population were suspected malaria cases, who visited the health centre for a diagnosis and treatment. Consecutive microscopy positive cases as well as a sample of microscopically negative cases were included for molecular analysis by polymerase chain reaction (PCR). RESULTS: 254 microscopically negative and 193 microscopically positive malaria suspects were included. Of the 193 malaria positive cases, 46.1% [95% confidence interval (CI) 38.9-53.4] (89/193) were P. falciparum infection, 52.3% (95% CI 45.0-59.5) (101/193) were P. vivax infection, and 1.6% (3/193) had mixed infection of P. falciparum and P. vivax. Of the microscopically positive cases of P. falciparum, 3.4% (3/89) were P. vivax and 11.2% (10/89) were mixed infections with P. falciparum and P. vivax and a single case was negative molecularly. Similarly, of the microscopically positive P. vivax cases, 5.9% (6/101) were P. falciparum and 1% (1/101) was mixed infection. Single case was negative by molecular technique. Of the 254 microscopically negative cases, 0.8% were tested positive for P. falciparum and 2% for P. vivax by PCR. Considering molecular technique as a reference, the sensitivity of microscopy for detecting P. falciparum was 89.2% and for P. vivax, it was 91.2%. The specificity of microscopy for detecting P. falciparum was 96.1% and for P. vivax, it was 97.7%. However, the sensitivity of microscopy in detecting mixed infection of P. falciparum and P. vivax was low (8.3%). CONCLUSION: There were cases left untreated or inappropriately treated due to the species misidentification. Therefore, to minimize this problem, the gaps in the microscopic-based malaria diagnosis should be identified. It is recommended to regularly monitor the competency of malaria microscopists in the study area to improve species identification and diagnosis accuracy.


Asunto(s)
Coinfección , Malaria Falciparum , Malaria Vivax , Malaria , Humanos , Estudios Transversales , Etiopía/epidemiología , Malaria/diagnóstico , Malaria Vivax/diagnóstico , Malaria Vivax/epidemiología , Malaria Vivax/prevención & control , Malaria Falciparum/diagnóstico , Malaria Falciparum/epidemiología
2.
Malar J ; 22(1): 235, 2023 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-37580690

RESUMEN

BACKGROUND: Urbanization generally improves health outcomes of residents and is one of the potential factors that might contribute to reducing malaria transmission. However, the expansion of Anopheles stephensi, an urban malaria vector, poses a threat for malaria control and elimination efforts in Africa. In this paper, malaria trends in urban settings in Ethiopia from 2014 to 2019 are reported with a focus on towns and cities where An. stephensi surveys were conducted. METHODS: A retrospective study was conducted to determine malaria trends in urban districts using passive surveillance data collected at health facilities from 2014 to 2019. Data from 25 towns surveyed for An. stephensi were used in malaria trend analysis. Robust linear models were used to identify outliers and impute missing and anomalous data. The seasonal Mann-Kendal test was used to test for monotonic increasing or decreasing trends. RESULTS: A total of 9,468,970 malaria cases were reported between 2014 and 2019 through the Public Health Emergency Management (PHEM) system. Of these, 1.45 million (15.3%) cases were reported from urban settings. The incidence of malaria declined by 62% between 2014 and 2018. In 2019, the incidence increased to 15 per 1000 population from 11 to 1000 in 2018. Both confirmed (microscopy or RDT) Plasmodium falciparum (67%) and Plasmodium vivax (28%) were reported with a higher proportion of P. vivax infections in urban areas. In 2019, An. stephensi was detected in 17 towns where more than 19,804 malaria cases were reported, with most of the cases (56%) being P. falciparum. Trend analysis revealed that malaria cases increased in five towns in Afar and Somali administrative regions, decreased in nine towns, and had no obvious trend in the remaining three towns. CONCLUSION: The contribution of malaria in urban settings is not negligible in Ethiopia. With the rapid expansion of An. stephensi in the country, the receptivity is likely to be higher for malaria. Although the evidence presented in this study does not demonstrate a direct linkage between An. stephensi detection and an increase in urban malaria throughout the country, An. stephensi might contribute to an increase in malaria unless control measures are implemented as soon as possible. Targeted surveillance and effective response are needed to assess the contribution of this vector to malaria transmission and curb potential outbreaks.


Asunto(s)
Anopheles , Malaria Falciparum , Malaria Vivax , Malaria , Animales , Humanos , Malaria/epidemiología , Malaria/prevención & control , Malaria/diagnóstico , Etiopía/epidemiología , Anopheles/fisiología , Estudios Retrospectivos , Mosquitos Vectores , Malaria Falciparum/epidemiología , Malaria Vivax/epidemiología
3.
Malar J ; 22(1): 135, 2023 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-37098510

RESUMEN

BACKGROUND: Ethiopia rolled out primaquine nationwide in 2018 for radical cure along with chloroquine for the treatment of uncomplicated Plasmodium vivax malaria in its bid for malaria elimination by 2030. The emergence of anti-malarial drug resistance would challenge the elimination goal. There is limited evidence on the emergence of chloroquine drug resistance. The clinical and parasitological outcomes of treatment of P. vivax with chloroquine plus radical cure using low dose 14 days primaquine were assessed in an endemic area of Ethiopia. METHODS: A semi-directly observed 42-days follow up in-vivo therapeutic efficacy study was conducted from October 2019 to February 2020. Plasmodium vivax mono-species infected patients (n = 102) treated with a 14 days low dose (0.25 mg/kg body weight per day) primaquine plus chloroquine (a total dose of 25 mg base/kg for 3 days) were followed for 42 days to examine clinical and parasitological outcomes. Samples collected at recruitment and days of recurrence were examined by 18 S based nested polymerase chain reaction (nPCR) and Pvmsp3α nPCR-restriction fragment length polymorphism. Asexual parasitaemia and the presence of gametocytes were assessed on the scheduled days using microscopy. Clinical symptoms, haemoglobin levels, and Hillmen urine test were also assessed. RESULTS: Of the 102 patients followed in this study, no early clinical and parasitological failure was observed. All patients had adequate clinical and parasitological responses within the 28 days of follow up. Late clinical (n = 3) and parasitological (n = 6) failures were observed only after day 28. The cumulative incidence of failure was 10.9% (95% confidence interval, 5.8-19.9%) on day 42. Among the paired recurrent samples, identical clones were detected only in two samples on day 0 and day of recurrences (day 30 and 42) using Pvmsp3α genotyping. No adverse effect was detected related to the low dose 14 days primaquine administrations. CONCLUSION: Co-administration of CQ with PQ in the study area is well tolerated and there was no recurrence of P. vivax before 28 days of follow up. Interpretation of CQ plus PQ efficacy should be done with caution especially when the recurrent parasitaemia occurs after day 28. Therapeutic efficacy studies with appropriate design might be informative to rule out chloroquine or primaquine drug resistance and/or metabolism in the study area.


Asunto(s)
Antimaláricos , Malaria Vivax , Humanos , Primaquina , Cloroquina/farmacología , Plasmodium vivax , Etiopía , Antimaláricos/farmacología , Malaria Vivax/tratamiento farmacológico , Malaria Vivax/prevención & control , Parasitemia/tratamiento farmacológico
4.
Emerg Infect Dis ; 27(2): 603-607, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33496217

RESUMEN

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.


Asunto(s)
Anopheles , Plasmodium vivax , Animales , Asia , Etiopía , Mosquitos Vectores , Plasmodium falciparum
5.
Cytokine ; 145: 155289, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-32951968

RESUMEN

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.


Asunto(s)
Quimiocinas/inmunología , Citocinas/inmunología , Inflamación/inmunología , Leishmania/inmunología , Leishmaniasis Cutánea/inmunología , Etiopía , Humanos , Inmunidad/inmunología , Inflamación/parasitología , Leishmaniasis Cutánea/parasitología , Leucocitos/inmunología , Leucocitos/parasitología
6.
Cytokine ; 145: 155246, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-32828639

RESUMEN

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.


Asunto(s)
Quimiocinas/inmunología , Citocinas/inmunología , Inflamación/inmunología , Leishmania donovani/inmunología , Leishmaniasis Visceral/inmunología , Adulto , Cultivo de Sangre/métodos , Estudios Transversales , Humanos , Sistema Inmunológico/inmunología , Inflamación/parasitología , Leishmaniasis Visceral/parasitología , Leucocitos/inmunología , Leucocitos/parasitología , Masculino
7.
Malar J ; 20(1): 59, 2021 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-33482841

RESUMEN

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.


Asunto(s)
Infecciones Asintomáticas/epidemiología , Malaria Falciparum/diagnóstico , Malaria Falciparum/epidemiología , Malaria Vivax/diagnóstico , Malaria Vivax/epidemiología , Adolescente , Adulto , Niño , Estudios Transversales , Pruebas con Sangre Seca , Etiopía/epidemiología , Femenino , Humanos , Malaria Falciparum/transmisión , Malaria Vivax/transmisión , Masculino , Microscopía/métodos , Persona de Mediana Edad , Plasmodium falciparum/genética , Plasmodium vivax/genética , Reacción en Cadena de la Polimerasa , Prevalencia , ARN Ribosómico 18S , Adulto Joven
8.
Malar J ; 20(1): 263, 2021 Jun 09.
Artículo en Inglés | MEDLINE | ID: mdl-34107943

RESUMEN

BACKGROUND: Anopheles stephensi, an invasive malaria vector, was first detected in Africa nearly 10 years ago. After the initial finding in Djibouti, it has subsequently been found in Ethiopia, Sudan and Somalia. To better inform policies and vector control decisions, it is important to understand the distribution, bionomics, insecticide susceptibility, and transmission potential of An. stephensi. These aspects were studied as part of routine entomological monitoring in Ethiopia between 2018 and 2020. METHODS: Adult mosquitoes were collected using human landing collections, pyrethrum spray catches, CDC light traps, animal-baited tent traps, resting boxes, and manual aspiration from animal shelters. Larvae were collected using hand-held dippers. The source of blood in blood-fed mosquitoes and the presence of sporozoites was assessed through enzyme-linked immunosorbent assays (ELISA). Insecticide susceptibility was assessed for pyrethroids, organophosphates and carbamates. RESULTS: Adult An. stephensi were collected with aspiration, black resting boxes, and animal-baited traps collecting the highest numbers of mosquitoes. Although sampling efforts were geographically widespread, An. stephensi larvae were collected in urban and rural sites in eastern Ethiopia, but An. stephensi larvae were not found in western Ethiopian sites. Blood-meal analysis revealed a high proportion of blood meals that were taken from goats, and only a small proportion from humans. Plasmodium vivax was detected in wild-collected An. stephensi. High levels of insecticide resistance were detected to pyrethroids, carbamates and organophosphates. Pre-exposure to piperonyl butoxide increased susceptibility to pyrethroids. Larvae were found to be susceptible to temephos. CONCLUSIONS: Understanding the bionomics, insecticide susceptibility and distribution of An. stephensi will improve the quality of a national response in Ethiopia and provide additional information on populations of this invasive species in Africa. Further work is needed to understand the role that An. stephensi will have in Plasmodium transmission and malaria case incidence. While additional data are being collected, national programmes can use the available data to formulate and operationalize national strategies against the threat of An. stephensi.


Asunto(s)
Distribución Animal , Anopheles/fisiología , Resistencia a los Insecticidas , Rasgos de la Historia de Vida , Animales , Anopheles/crecimiento & desarrollo , Etiopía , Insecticidas/farmacología , Larva/crecimiento & desarrollo , Larva/fisiología , Malaria/transmisión
9.
BMC Infect Dis ; 21(1): 91, 2021 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-33478414

RESUMEN

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.


Asunto(s)
Malaria/epidemiología , Altitud , Demografía , Notificación de Enfermedades/normas , Notificación de Enfermedades/estadística & datos numéricos , Etiopía/epidemiología , Femenino , Humanos , Malaria/diagnóstico , Malaria/parasitología , Malaria/prevención & control , Masculino , Meteorología , Análisis Multivariante , Plasmodium falciparum/aislamiento & purificación , Plasmodium vivax/aislamiento & purificación , Prevalencia , Estudios Retrospectivos , Estaciones del Año
10.
BMC Microbiol ; 20(1): 90, 2020 04 15.
Artículo en Inglés | MEDLINE | ID: mdl-32293265

RESUMEN

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.


Asunto(s)
Pruebas de Aglutinación/métodos , Anticuerpos Antiprotozoarios/sangre , Antígenos de Protozoos/inmunología , Leishmania donovani/inmunología , Leishmaniasis Visceral/diagnóstico , Adolescente , Adulto , Pruebas Diagnósticas de Rutina , Enfermedades Endémicas , Etiopía/epidemiología , Femenino , Humanos , Leishmaniasis Visceral/inmunología , Masculino , Persona de Mediana Edad , Sensibilidad y Especificidad , Adulto Joven
11.
BMC Infect Dis ; 20(1): 639, 2020 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-32867694

RESUMEN

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.


Asunto(s)
Anticuerpos Antivirales/sangre , Virus del Dengue/inmunología , Dengue/sangre , Dengue/epidemiología , Fiebre/sangre , Fiebre/epidemiología , Adolescente , Adulto , Animales , Estudios Transversales , Dengue/diagnóstico , Dengue/virología , Etiopía/epidemiología , Femenino , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Masculino , Persona de Mediana Edad , Prevalencia , Factores de Riesgo , Encuestas y Cuestionarios , Adulto Joven
12.
BMC Struct Biol ; 19(1): 6, 2019 03 27.
Artículo en Inglés | MEDLINE | ID: mdl-30917807

RESUMEN

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.


Asunto(s)
Antígenos de Protozoos/química , Antígenos de Protozoos/inmunología , Malaria Vivax/inmunología , Plasmodium vivax/aislamiento & purificación , Proteínas Protozoarias/química , Proteínas Protozoarias/inmunología , Sustitución de Aminoácidos , Antígenos de Protozoos/genética , Epítopos de Linfocito B/metabolismo , Etiopía , Humanos , Evasión Inmune , Malaria Vivax/parasitología , Modelos Moleculares , Filogenia , Plasmodium vivax/inmunología , Plasmodium vivax/metabolismo , Polimorfismo Genético , Dominios Proteicos , Estructura Terciaria de Proteína , Proteínas Protozoarias/genética
13.
Clin Infect Dis ; 66(12): 1883-1891, 2018 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-29304258

RESUMEN

Background: The majority of Plasmodium vivax and Plasmodium falciparum infections in low-endemic settings are asymptomatic. The relative contribution to the infectious reservoir of these infections compared to clinical malaria cases is currently unknown. Methods: We assessed infectivity of passively recruited symptomatic malaria patients (n = 41) and community-recruited asymptomatic individuals with microscopy-detected (n = 41) and polymerase chain reaction (PCR)-detected infections (n = 82) using membrane feeding assays with Anopheles arabiensis mosquitoes in Adama, Ethiopia. Malaria incidence and prevalence data were used to estimate the contributions of these populations to the infectious reservoir. Results: Overall, 34.9% (29/83) of P. vivax- and 15.1% (8/53) P. falciparum-infected individuals infected ≥1 mosquitoes. Mosquito infection rates were strongly correlated with asexual parasite density for P. vivax (ρ = 0.63; P < .001) but not for P. falciparum (ρ = 0.06; P = .770). Plasmodium vivax symptomatic infections were more infectious to mosquitoes (infecting 46.5% of mosquitoes, 307/660) compared to asymptomatic microscopy-detected (infecting 12.0% of mosquitoes, 80/667; P = .005) and PCR-detected infections (infecting 0.8% of mosquitoes, 6/744; P < .001). Adjusting for population prevalence, symptomatic, asymptomatic microscopy-detected, and PCR-detected infections were responsible for 8.0%, 76.2%, and 15.8% of the infectious reservoir for P. vivax, respectively. For P. falciparum, mosquito infections were sparser and also predominantly from asymptomatic infections. Conclusions: In this low-endemic setting aiming for malaria elimination, asymptomatic infections were highly prevalent and responsible for the majority of onward mosquito infections. The early identification and treatment of asymptomatic infections might accelerate elimination efforts.


Asunto(s)
Anopheles/parasitología , Infecciones Asintomáticas/epidemiología , Reservorios de Enfermedades/parasitología , Malaria Falciparum/epidemiología , Malaria Vivax/epidemiología , Adolescente , Adulto , Animales , Niño , Preescolar , Enfermedades Endémicas/estadística & datos numéricos , Etiopía/epidemiología , Femenino , Humanos , Malaria Falciparum/transmisión , Malaria Vivax/transmisión , Masculino , Plasmodium falciparum/genética , Plasmodium falciparum/aislamiento & purificación , Plasmodium vivax/genética , Plasmodium vivax/aislamiento & purificación , Reacción en Cadena de la Polimerasa , Prevalencia , Adulto Joven
14.
BMC Med ; 16(1): 11, 2018 01 18.
Artículo en Inglés | MEDLINE | ID: mdl-29347975

RESUMEN

BACKGROUND: In 2012, the World Health Organization recommended blocking the transmission of Plasmodium falciparum with single low-dose primaquine (SLDPQ, target dose 0.25 mg base/kg body weight), without testing for glucose-6-phosphate dehydrogenase deficiency (G6PDd), when treating patients with uncomplicated falciparum malaria. We sought to develop an age-based SLDPQ regimen that would be suitable for sub-Saharan Africa. METHODS: Using data on the anti-infectivity efficacy and tolerability of primaquine (PQ), the epidemiology of anaemia, and the risks of PQ-induced acute haemolytic anaemia (AHA) and clinically significant anaemia (CSA), we prospectively defined therapeutic-dose ranges of 0.15-0.4 mg PQ base/kg for children aged 1-5 years and 0.15-0.5 mg PQ base/kg for individuals aged ≥6 years (therapeutic indices 2.7 and 3.3, respectively). We chose 1.25 mg PQ base for infants aged 6-11 months because they have the highest rate of baseline anaemia and the highest risks of AHA and CSA. We modelled an anthropometric database of 661,979 African individuals aged ≥6 months (549,127 healthy individuals, 28,466 malaria patients and 84,386 individuals with other infections/illnesses) by the Box-Cox transformation power exponential and tested PQ doses of 1-15 mg base, selecting dosing groups based on calculated mg/kg PQ doses. RESULTS: From the Box-Cox transformation power exponential model, five age categories were selected: (i) 6-11 months (n = 39,886, 6.03%), (ii) 1-5 years (n = 261,036, 45.46%), (iii) 6-9 years (n = 20,770, 3.14%), (iv) 10-14 years (n = 12,155, 1.84%) and (v) ≥15 years (n = 328,132, 49.57%) to receive 1.25, 2.5, 5, 7.5 and 15 mg PQ base for corresponding median (1st and 99th centiles) mg/kg PQ base of: (i) 0.16 (0.12-0.25), (ii) 0.21 (0.13-0.37), (iii) 0.25 (0.16-0.38), (iv) 0.26 (0.15-0.38) and (v) 0.27 (0.17-0.40). The proportions of individuals predicted to receive optimal therapeutic PQ doses were: 73.2 (29,180/39,886), 93.7 (244,537/261,036), 99.6 (20,690/20,770), 99.4 (12,086/12,155) and 99.8% (327,620/328,132), respectively. CONCLUSIONS: We plan to test the safety of this age-based dosing regimen in a large randomised placebo-controlled trial (ISRCTN11594437) of uncomplicated falciparum malaria in G6PDd African children aged 0.5 - 11 years. If the regimen is safe and demonstrates adequate pharmacokinetics, it should be used to support malaria elimination.


Asunto(s)
Antimaláricos/uso terapéutico , Malaria Falciparum/prevención & control , Primaquina/uso terapéutico , Adolescente , Adulto , África del Sur del Sahara , Factores de Edad , Anciano , Anciano de 80 o más Años , Antimaláricos/administración & dosificación , Antimaláricos/efectos adversos , Niño , Preescolar , Protocolos Clínicos , Relación Dosis-Respuesta a Droga , Femenino , Deficiencia de Glucosafosfato Deshidrogenasa , Humanos , Lactante , Malaria Falciparum/tratamiento farmacológico , Malaria Falciparum/transmisión , Masculino , Persona de Mediana Edad , Plasmodium falciparum , Primaquina/administración & dosificación , Primaquina/efectos adversos , Adulto Joven
15.
Malar J ; 17(1): 281, 2018 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-30071859

RESUMEN

BACKGROUND: 8-Aminoquinolines such as primaquine clear mature Plasmodium falciparum gametocytes that are responsible for transmission from human to mosquitoes and bring radical cure in Plasmodium vivax by clearing dormant liver stages. Deployment of primaquine is thus of relevance for malaria elimination efforts but challenged by the widespread prevalence of glucose-6-phosphate dehydrogenase deficiency (G6PDd) in endemic countries since primaquine in G6PDd individuals may lead to acute haemolysis. In this study, the prevalence of G6PDd was investigated in different settings in Ethiopia using phenotyping and genotyping approaches. METHODS: Community and school based cross-sectional surveys were conducted from October to December 2016 in four administrative regions (Gambela, Benishangul Gumuz, Oromia, and Amhara) in Ethiopia. Finger prick blood samples were collected for G6PD enzyme activity using the CareStart™ G6PD screening test and genotyping of 36 selected single nucleotide polymorphisms (SNPs) located in the G6PD gene and its flanking regions. RESULTS: Overall, the prevalence of phenotypic G6PDd was 1.4% (22/1609). For the first time in the Ethiopian population, the African variant (A-) was detected in 3.5% (7/199) of the limited set of genotyped samples, which were all phenotypically normal. Interestingly, all of these individuals had a variation at the rs2515904 locus. Strong geographical variation was observed for both phenotypic and genotypic G6PDd; three-quarters of the phenotypically G6PDd individuals were detected in Gambela. CONCLUSION: A very low prevalence of G6PDd was detected in the present study populations. The presence of the A- variant alongside other G6PD mutants and the patchy distribution of G6PDd indicate that larger studies specifically designed to unravel the distribution of G6PDd at small geographical scale may be needed to tailor malaria elimination efforts in Ethiopia to the local context.


Asunto(s)
Deficiencia de Glucosafosfato Deshidrogenasa/epidemiología , Polimorfismo de Nucleótido Simple , Adolescente , Adulto , Niño , Estudios Transversales , Etiopía/epidemiología , Femenino , Genotipo , Deficiencia de Glucosafosfato Deshidrogenasa/genética , Deficiencia de Glucosafosfato Deshidrogenasa/parasitología , Humanos , Masculino , Fenotipo , Prevalencia , Adulto Joven
16.
BMC Infect Dis ; 18(1): 616, 2018 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-30514223

RESUMEN

BACKGROUND: Dengue is one of the most common arboviral diseases with increased outbreaks annually in tropical and subtropical areas. In Ethiopia, there are no data regarding clinical, hematological and biochemical parameters which are very important in the clinical management of dengue patients. Hence this study was carried out to provide the first baseline data of clinical, hematological and biochemical profiles of patients infected with dengue virus. METHODS: A cross-sectional study was carried out among febrile patients in northwest Ethiopia from March 2016 to May 2017. Blood samples were collected from dengue presumed cases and tested against dengue specific IgM antibody by enzyme-linked immunosorbent assay (ELISA). Those study participants who fulfilled the inclusion criteria were enrolled in the study. Clinical examination findings were recorded, hematological and biochemical parameters tests were done. RESULTS: During the study period, a total of 102 dengue cases were included in the study. Of these, there were 16 (15.7%) children and 86 (84.3%) adults between 1 and 76 year age. The most common clinical presentations followed by fever (100%) were a headache 89 (87.3%), myalgia 82 (80.4%), nausea/vomiting 71 (69.6%). The common hematological findings were thrombocytopenia 61 (59.8%), followed by anemia 45 (44.1%) and leucopenia 27 (26.5%) and the elevated levels of biochemical parameters were AST 46 (45.1%) and ALT in 18 (17.6%). CONCLUSIONS: This study highlights the most common clinical and laboratory profiles of dengue viral infections that could alert physicians to the likelihood of dengue virus infections in the study area.


Asunto(s)
Biomarcadores/sangre , Virus del Dengue , Dengue/sangre , Dengue/epidemiología , Dengue/terapia , Adolescente , Adulto , Anciano , Biomarcadores/análisis , Niño , Preescolar , Estudios Transversales , Dengue/diagnóstico , Virus del Dengue/inmunología , Brotes de Enfermedades/estadística & datos numéricos , Etiopía/epidemiología , Femenino , Fiebre/sangre , Fiebre/epidemiología , Cefalea/sangre , Cefalea/epidemiología , Humanos , Lactante , Leucopenia/sangre , Leucopenia/epidemiología , Masculino , Persona de Mediana Edad , Pronóstico , Trombocitopenia/sangre , Trombocitopenia/epidemiología , Adulto Joven
17.
Cytokine ; 91: 6-9, 2017 03.
Artículo en Inglés | MEDLINE | ID: mdl-27940090

RESUMEN

BACKGROUND: In Ethiopia, visceral leishmaniasis (VL) is a growing public health threat. Among the key challenges in VL control in Ethiopia is lack of an effective test of cure. The recommended test of cure is parasite detection. As sterile cure is not expected with the current widely used drugs, the value of parasite detection as test of cure is questionable. Moreover, the sampling is invasive, requires a well-equipped facility and highly skilled personnel, which are all hardly found in endemic set-ups. OBJECTIVE: Our aim was to assess the value of sCD40L, MMP9 and IL-10 serum levels as signature biomarkers of clinical cure in VL cases from Ethiopia. METHODS: A total of 45 VL cases before and after treatment and 30 endemic healthy controls were included in the study. Sandwich ELISA was used to measure serum levels of sCD40L, MMP9 and IL-10. RESULT: The mean sCD40L, MMP9 and IL-10 serum levels changed significantly at clinical cure. At individual case level sCD40L and MMP9 showed an increasing trend. Yet, the degree of increase in serum level of MMP9 seems to be affected by nutritional status of the individual VL case. The mean IL-10 serum level was significantly reduced at clinical cure. As seen on case by case basis, all demonstrated a declining trend except that two VL cases had a high IL10 level at clinical cure. CONCLUSION: Our result is suggestive of the possibility of developing a signature biomarker to monitor VL treatment in Ethiopia using one or a combination of parameters.


Asunto(s)
Gluconato de Sodio Antimonio/administración & dosificación , Ligando de CD40/sangre , Interleucina-10/sangre , Leishmaniasis Visceral , Metaloproteinasa 9 de la Matriz/sangre , Adulto , Etiopía , Femenino , Humanos , Leishmaniasis Visceral/sangre , Leishmaniasis Visceral/tratamiento farmacológico , Masculino
18.
Malar J ; 16(1): 356, 2017 09 06.
Artículo en Inglés | MEDLINE | ID: mdl-28877707

RESUMEN

BACKGROUND: The malaria infection status of mosquitoes is commonly determined by microscopic detection of oocysts on the dissected mosquito midgut. This method is labour-intensive, does not allow processing of large numbers of mosquitoes and can be challenging in terms of objective classification of oocysts. Here, a semi-high-throughput bead-beating ELISA method is proposed for detection of the circumsporozoite protein (CSP) followed by confirmation by quantitative PCR (qPCR). METHODS: Cultured Plasmodium falciparum gametocytes were offered to Anopheles stephensi mosquitoes and examined by microscopy. After bead-beating, mosquito homogenate was examined by CSP-ELISA and 18S qPCR. As negative controls, mosquitoes that were offered a heat-inactivated gametocyte blood meal were used. The CSP-ELISA/qPCR methodology was applied to high and low-intensity infections of cultured P. falciparum gametocytes. A similar methodology optimized for P. vivax was used on mosquitoes that were offered blood from Ethiopian donors who were naturally infected with P. vivax. RESULTS: There was considerable variation in CSP-ELISA signal and qPCR values in mosquitoes with low oocyst intensities. There was a strong agreement mosquito positivity by CSP-ELISA and by qPCR in mosquitoes that fed on cultured P. falciparum material (agreement 96.9%; kappa = 0.97) and naturally infected P. vivax parasite carriers [agreement 92.4% (kappa = 0.83)]. CONCLUSIONS: The proposed bead-beating CSP-ELISA/qPCR methodology considerably increases throughput for the detection of mosquito infection. qPCR remains necessary to confirm infections in mosquitoes with low CSP-ELISA signal. This methodology may prove particularly useful for studies where very low mosquito infection prevalence is expected and study sites where experience with oocyst detection is limited.


Asunto(s)
Anopheles/parasitología , Ensayo de Inmunoadsorción Enzimática/métodos , Plasmodium falciparum/aislamiento & purificación , Plasmodium vivax/aislamiento & purificación , Proteínas Protozoarias/sangre , Proteínas Protozoarias/aislamiento & purificación , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Animales , Antígenos de Protozoos/sangre , Antígenos de Protozoos/aislamiento & purificación , ADN Protozoario , Femenino , Humanos , Insectos Vectores/parasitología , Oocistos , Plasmodium falciparum/clasificación , Plasmodium falciparum/genética , Plasmodium vivax/clasificación , Plasmodium vivax/genética , ARN Ribosómico 18S/genética , Sensibilidad y Especificidad
20.
Ethiop Med J ; 54(1): 33-6, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27191028

RESUMEN

Visceral leishmaniasis (VL) is a ftial and growing public health problem in Ethiopia. VL is recently reported outside the major endemic foci, the lowlands in the northwest and the Omo and Abaroba-plain, Segen and Woito valleys in the southwest. Here, we report a visceral leishmaniasis case from Benishangul-Gumuz Regional state near the Guba area. The patient had no history of travel to known VL endemic areas. The patient is a temporary farm laborer from West Go'jam Zone, Wanbermna District in Amhara Regional State. While in Benishangul-Gumuz, the patient was diagnosed with prolonged and intermittentfever, epistaxis, splenomegaly, skin pallor, diarrhea, cough and oedema. Laboratory diagnosis results showed that he had marked leucopenia, thrombocytopenia and anemia. The patient was suspected of having VL and checked with rK39 immunochromnatography and direct agglutination tests which were positive for anti leishmanial antibodies. After getting full dose of sodium stibogluconate as per the national visceral leishmaniasis treatment guideline, was clinically cured. As the area in Benshangul-Gumuz where this patient contracted visceral leishmaniasis is under social and ecological transformation with large scale projects attracting huge influx of temporary laborers and settlers, due attention is needed with respect to introduction or emergence of VL transmission.


Asunto(s)
Gluconato de Sodio Antimonio/administración & dosificación , Leishmania donovani/inmunología , Leishmaniasis Visceral , Antiprotozoarios/administración & dosificación , Etiopía/epidemiología , Humanos , Leishmaniasis Visceral/diagnóstico , Leishmaniasis Visceral/tratamiento farmacológico , Leishmaniasis Visceral/epidemiología , Leishmaniasis Visceral/etiología , Leishmaniasis Visceral/fisiopatología , Masculino , Pruebas Serológicas , Resultado del Tratamiento , Adulto Joven
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