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1.
BMC Infect Dis ; 20(1): 835, 2020 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-33176708

RESUMO

BACKGROUND: The spatial distribution and burden of dengue in sub-Saharan Africa remains highly uncertain, despite high levels of ecological suitability. The goal of this study was to describe the epidemiology of dengue among a cohort of febrile children presenting to outpatient facilities located in areas of western Uganda with differing levels of urbanicity and malaria transmission intensity. METHODS: Eligible children were first screened for malaria using rapid diagnostic tests. Children with a negative malaria result were tested for dengue using a combination NS1/IgM/IgG rapid test (SD Bioline Dengue Duo). Confirmatory testing by RT-PCR was performed in a subset of participants. Antigen-capture ELISA was performed to estimate seroprevalence. RESULTS: Only 6 of 1416 (0.42%) children had a positive dengue rapid test, while none of the RT-PCR results were positive. ELISA testing demonstrated reactive IgG antibodies in 28 (2.2%) participants with the highest prevalence seen at the urban site in Mbarara (19 of 392, 4.9%, p < 0.001). CONCLUSIONS: Overall, these findings suggest that dengue, while present, is an uncommon cause of non-malarial, pediatric febrile illness in western Uganda. Further investigation into the eocological factors that sustain low-level transmission in urban settings are urgently needed to reduce the risk of epidemics.


Assuntos
Vírus da Dengue/genética , Vírus da Dengue/imunologia , Dengue/diagnóstico , Dengue/epidemiologia , Febre/diagnóstico , Adolescente , Criança , Pré-Escolar , Dengue/virologia , Testes Diagnósticos de Rotina/efeitos adversos , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Malária/diagnóstico , Malária/epidemiologia , Malária/parasitologia , Masculino , Plasmodium/imunologia , Plasmodium/isolamento & purificação , Prevalência , Estudos Prospectivos , Reação em Cadeia da Polimerase em Tempo Real , Estudos Soroepidemiológicos , Uganda/epidemiologia
2.
Am J Trop Med Hyg ; 103(4): 1549-1552, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32748776

RESUMO

Plasmodium vivax is co-endemic with Plasmodium falciparum in Peru, and optimum management requires distinguishing these two species in the blood of patients. For the differential identification of P. vivax and other Plasmodium spp., the LoopampTM Malaria Pan Detection Kit in combination with the Loopamp Malaria Pv Detection Kit (Eiken Chemical Co. Ltd., Tokyo, Japan) was used to evaluate 559 whole blood samples collected in 2017 from febrile patients with suspected malaria attending different health facilities in the Loreto region. The Loopamp Malaria Pan Detection Kit showed a sensitivity of 87.7% (95% CI: 83.5-91.9) and a specificity of 94.4% (95% CI: 91.9-96.9) and good agreement with PCR (Cohen's kappa 0.8266, 95% CI: 0.7792-0.874). By comparison, the Loopamp Malaria Pv Detection Kit showed a similar sensitivity (84.4%, 95% CI: 79.0-89.7) and specificity (92.4%, 95% CI: 89.7-95.0) and substantial agreement with PCR (Cohen's kappa: 0.7661, 95% CI: 0.7088-0.8234).


Assuntos
Malária Vivax/diagnóstico , Malária/diagnóstico , Plasmodium vivax/isolamento & purificação , Plasmodium/isolamento & purificação , Febre , Humanos , Malária/parasitologia , Malária Vivax/parasitologia , Técnicas de Amplificação de Ácido Nucleico , Peru , Plasmodium/genética , Plasmodium vivax/genética , Reação em Cadeia da Polimerase , Sensibilidade e Especificidade
3.
Am J Trop Med Hyg ; 103(4): 1510-1516, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32783792

RESUMO

The prevalence of malaria in India is decreasing, but it remains a major concern for public health administration. The role of submicroscopic malaria and asymptomatic malaria parasitemia and their persistence is being explored. A cross-sectional survey was conducted in the Kandhamal district of Odisha (India) during May-June 2017. Blood samples were collected from 1897 individuals for screening of asymptomatic parasitemia. Samples were screened using rapid diagnostic tests (RDTs) and examined microscopically for Plasmodium species. Approximately 30% of randomly selected samples (n = 586) were analyzed using real-time PCR (qPCR), and the genetic diversity of Plasmodium falciparum was analyzed. The prevalence of Plasmodium species among asymptomatic individuals detected using qPCR was 18%, which was significantly higher than that detected by microscopy examination (5.5%) or RDT (7.3%). Of these, 37% had submicroscopic malaria. The species-specific prevalence among asymptomatic malaria-positive cases for P. falciparum, Plasmodium vivax, and mixed infection (P. falciparum and P. vivax) by qPCR was 57%, 29%, and 14%, respectively. The multiplicity of infection was 1.6 and 1.2 for the merozoite surface protein-1 gene (msp1) and (msp2), respectively. Expected heterozygosity was 0.64 and 0.47 for msp1 and msp2, respectively. A significant proportion of the study population, 105/586 (18%), was found to be a reservoir for malaria infection, and identification of this group will help in the development of elimination strategies.


Assuntos
Malária/epidemiologia , Parasitemia/epidemiologia , Plasmodium/isolamento & purificação , Adolescente , Adulto , Criança , Pré-Escolar , Coinfecção , Erradicação de Doenças , Feminino , Humanos , Índia/epidemiologia , Malária/parasitologia , Malária/prevenção & controle , Masculino , Parasitemia/parasitologia , Parasitemia/prevenção & controle , Plasmodium/genética , Reação em Cadeia da Polimerase em Tempo Real , Especificidade da Espécie , Adulto Jovem
4.
Am J Trop Med Hyg ; 103(5): 1918-1926, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32815500

RESUMO

The number of Asian migrants working in sub-Saharan developing countries like Angola has been increasing. Their malaria risk, prevention, and care-seeking practices have not been characterized. A cross-sectional survey was conducted in 733 Chinese and Southeast Asian migrants in Angola. Respondents were interviewed and provided blood samples. Samples were analyzed to detect Plasmodium antigen and characterize host anti-Plasmodium response. Positive samples were genotyped using the pfs47 marker. Most respondents (72%; 95% CI: 68-75) reported using bed nets, but less than 1% reported using chemoprophylaxis. Depending on the assay, 1-4% of respondents had evidence of active malaria infection. By contrast, 55% (95% CI: 52-59) were seropositive for Plasmodium antibodies. Most infections were Plasmodium falciparum, but infection and/or exposure to Plasmodium vivax and Plasmodium malariae was also detected. Seroprevalence by time in Angola showed most exposure occurred locally. One respondent had sufficiently high parasitemia for pfs47 genotyping, which showed that the infection was likely locally acquired despite recent travel to home country. Asian migrants to Angola are at substantial risk of malaria. Employers should consider enhanced malaria prevention programs, including chemoprophylaxis; embassies should encourage prevention practices. Angolan healthcare workers should be aware of high malaria exposure in Asian migrants.


Assuntos
Malária/epidemiologia , Plasmodium/imunologia , Migrantes/estatística & dados numéricos , Adulto , Angola/epidemiologia , Estudos Transversais , Feminino , Humanos , Incidência , Malária/parasitologia , Malária/prevenção & controle , Masculino , Pessoa de Meia-Idade , Plasmodium/genética , Plasmodium/isolamento & purificação , Vigilância da População , Prevalência , Fatores de Risco , Estudos Soroepidemiológicos
5.
Int J Infect Dis ; 98: 408-419, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32659450

RESUMO

BACKGROUND: Diagnosis is a challenging issue for eliminating malaria. Loop-mediated isothermal amplification (LAMP) could be an alternative to conventional methods. This study aimed to evaluate the diagnostic accuracy of LAMP for malaria compared with microscopy, polymerase chain reaction (PCR) and rapid diagnostic tests (RDTs). METHODS AND DESIGN: MEDLINE, Web of Science and Scopus were searched from inception to 1 July 2019. Prospective and retrospective, randomised and non-randomised, mono-center and multi-center studies, including symptomatic or asymptomatic patients, that reported one LAMP method and one comparator (microscopy, RDT or PCR) were included. PROSPERO registration number: CRD42017075186. RESULTS: Sixty-six studies published between 2006 and 2019 were included, leading to the analysis of 30,641 LAMP tests. The pooled sensitivity of LAMP remained between 96% and 98%, whichever the comparator. The pooled specificity of LAMP was around 95%, but was a little higher if the best PCR studies were considered. The AUC was found to be >0.98, whichever the subgroup of studies was considered. Diagnostic odds ratio (DOR) was found to be around 1000 for all subgroups, except for Plasmodium vivax. CONCLUSION: This meta-analysis confirmed that the LAMP method is robust for diagnosing malaria, both in symptomatic and asymptomatic people. Thus, the impact of LAMP for controlling malaria is expected to be important.


Assuntos
Testes Diagnósticos de Rotina/normas , Malária/diagnóstico , Microscopia/normas , Técnicas de Amplificação de Ácido Nucleico/normas , Plasmodium/isolamento & purificação , Reação em Cadeia da Polimerase/normas , Testes Diagnósticos de Rotina/métodos , Humanos , Malária/parasitologia , Microscopia/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , Plasmodium/classificação , Plasmodium/genética , Plasmodium/fisiologia , Reação em Cadeia da Polimerase/métodos , Estudos Prospectivos , Estudos Retrospectivos , Sensibilidade e Especificidade
6.
Mem Inst Oswaldo Cruz ; 115: e200043, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32667459

RESUMO

BACKGROUND The number of malaria cases in Roraima nearly tripled from 2016 to 2018. The capital, Boa Vista, considered a low-risk area for malaria transmission, reported an increasing number of autochthonous and imported cases. OBJECTIVES This study describes a spatial analysis on malaria cases in an urban region of Boa Vista, which sought to identify the autochthonous and imported cases and associated them with Anopheles habitats and the potential risk of local transmission. METHODS In a cross-sectional study at the Polyclinic Cosme e Silva, 520 individuals were interviewed and diagnosed with malaria by microscopic examination. Using a global positional system, the locations of malaria cases by type and origin and the breeding sites of anopheline vectors were mapped and the risk of malaria transmission was evaluated by spatial point pattern analysis. FINDINGS Malaria was detected in 57.5% of the individuals and there was a disproportionate number of imported cases (90.6%) linked to Brazilian coming from gold mining sites in Venezuela and Guyana. MAIN CONCLUSIONS The increase in imported malaria cases circulating in the west region of Boa Vista, where there are positive breeding sites for the main vectors, may represent a potential condition for increased autochthonous malaria transmission in this space.


Assuntos
Anopheles/parasitologia , Malária/diagnóstico , Malária/transmissão , Mineradores/estatística & dados numéricos , Mosquitos Vetores/parasitologia , Plasmodium/isolamento & purificação , Viagem , Adulto , Animais , Anopheles/classificação , Brasil/epidemiologia , Estudos Transversais , Feminino , Sistemas de Informação Geográfica , Ouro , Guiana , Humanos , Malária/epidemiologia , Malária/parasitologia , Masculino , Pessoa de Meia-Idade , Plasmodium/classificação , Análise Espacial , População Urbana , Venezuela
7.
Am J Trop Med Hyg ; 103(3): 1107-1110, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32618263

RESUMO

Asymptomatic and/or low-density malaria infection has been acknowledged as an obstacle to achieving a malaria-free country. This study aimed to determine the prevalence of asymptomatic and/or low-density malaria infection in previously reported malarious localities using nested PCR in four states, namely, Johor, Pahang, Kelantan, and Selangor, between June 2019 and January 2020. Blood samples (n = 585) were collected and were extracted using a QIAamp blood kit. The DNA was concentrated and subjected to nested PCR. Thin and thick blood smears were examined as well. Of the 585 samples collected, 19 were positive: 10 for Plasmodium knowlesi, eight for Plasmodium vivax, and one for Plasmodium ovale. Asymptomatic and/or low-density malaria infection is a threat to malaria elimination initiatives. Eliminating countries should develop guidance policy on the importance of low-density malaria infection which includes detection and treatment policy.


Assuntos
Infecções Assintomáticas/epidemiologia , Malária Vivax/epidemiologia , Malária/epidemiologia , Plasmodium/isolamento & purificação , Adolescente , Adulto , Feminino , Humanos , Malária/parasitologia , Malária Vivax/parasitologia , Malásia/epidemiologia , Masculino , Pessoa de Meia-Idade , Plasmodium/genética , Plasmodium knowlesi/genética , Plasmodium knowlesi/isolamento & purificação , Plasmodium ovale/genética , Plasmodium ovale/isolamento & purificação , Plasmodium vivax/genética , Plasmodium vivax/isolamento & purificação , Reação em Cadeia da Polimerase , Prevalência , Adulto Jovem
8.
Malar J ; 19(1): 129, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-32228615

RESUMO

BACKGROUND: The World Health Organization (WHO) recommends parasite-based diagnosis of malaria. In recent years, there has been surge in the use of various kinds of nucleic-acid amplification based tests (NAATs) for detection and identification of Plasmodium spp. to support clinical care in high-resource settings and clinical and epidemiological research worldwide. However, these tests are not without challenges, including lack (or limited use) of standards and lack of reproducibility, due in part to variation in protocols amongst laboratories. Therefore, there is a need for rigorous quality control, including a robust external quality assessment (EQA) scheme targeted towards malaria NAATs. To this effect, the WHO Global Malaria Programme worked with the UK National External Quality Assessment Scheme (UK NEQAS) Parasitology and with technical experts to launch a global NAAT EQA scheme in January 2017. METHODS: Panels of NAAT EQA specimens containing five major species of human-infecting Plasmodium at various parasite concentrations and negative samples were created in lyophilized blood (LB) and dried blood spot (DBS) formats. Two distributions per year were sent, containing five LB and five DBS specimens. Samples were tested and validated by six expert referee laboratories prior to distribution. Between 37 and 45 laboratories participated in each distribution and submitted results using the online submission portal of UK NEQAS. Participants were scored based on their laboratory's stated capacity to identify Plasmodium species, and individual laboratory reports were sent which included performance comparison with anonymized peers. RESULTS: Analysis of the first three distributions revealed that the factors that most significantly affected performance were sample format (DBS vs LB), species and parasite density, while laboratory location and the reported methodology used (type of nucleic acid extraction, amplification, or DNA vs RNA target) did not significantly affect performance. Referee laboratories performed better than non-referee laboratories. CONCLUSIONS: Globally, malaria NAAT assays now inform a range of clinical, epidemiological and research investigations. EQA schemes offer a way for laboratories to assess and improve their performance, which is critical to safeguarding the reliability of data and diagnoses especially in situations where various NAAT methodologies and protocols are in use.


Assuntos
Testes Diagnósticos de Rotina/estatística & dados numéricos , Malária/diagnóstico , Técnicas de Amplificação de Ácido Nucleico/estatística & dados numéricos , Plasmodium/isolamento & purificação , Garantia da Qualidade dos Cuidados de Saúde/estatística & dados numéricos , Humanos , Controle de Qualidade , Reprodutibilidade dos Testes , Organização Mundial da Saúde
9.
Parasitol Res ; 119(5): 1563-1572, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32246260

RESUMO

In temperate regions, some avian haemosporidian parasites have evolved seasonal transmission strategies, with chronic infections relapsing during spring and transmission peaking during the hosts' breeding season. Because lineages with seasonal transmission strategies are unlikely to produce gametocytes in winter, we predicted that (1) resident birds living within wintering areas of Neotropical migrants would unlikely be infected with North American parasite lineages; and (2) if infected, wintering migratory birds would be more likely to harbor Plasmodium spp. rather than Parahaemoproteus spp. or Haemoproteus spp. parasites in their bloodstreams, as only Plasmodium produces life stages, other than gametocytes, that infect red blood cells. To test these predictions, we used molecular detection and microscopy to compare the diversity and prevalence of haemosporidian parasites among year-round residents and wintering migratory birds during February 2016, on three islands of The Bahamas archipelago, i.e., Andros, Grand Bahama, and Great Abaco. Infection prevalence was low and comparable between migratory (15/111) and resident (15/129) individuals, and it did not differ significantly among islands. Out of the 12 lineages detected infecting migratory birds, five were transmitted in North America; four lineages could have been transmitted during breeding, wintering, or migration; and three lineages were likely transmitted in The Bahamas. Resident birds mostly carried lineages endemic to the Caribbean region. All North American-transmitted parasite lineages detected among migratory birds were Plasmodium spp. Our findings suggest that haemosporidian parasites of migrants shift resource allocation seasonally, minimizing the production of gametocytes during winter, with low risk of infection spillover to resident birds.


Assuntos
Doenças das Aves/parasitologia , Aves/parasitologia , Haemosporida/isolamento & purificação , Plasmodium/isolamento & purificação , Infecções Protozoárias em Animais/epidemiologia , Migração Animal/fisiologia , Animais , Bahamas/epidemiologia , Doenças das Aves/epidemiologia , Haemosporida/classificação , Haemosporida/genética , Plasmodium/genética , Prevalência , Infecções Protozoárias em Animais/parasitologia , Estações do Ano
10.
J Zoo Wildl Med ; 51(1): 140-149, 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32212557

RESUMO

Vector-borne Plasmodium spp. infect a wide range of bird species. Although infections may be asymptomatic, certain genera, especially those that evolved in regions without endemic malaria, appear particularly susceptible to symptomatic disease, leading to morbidity and mortality. High mortalities associated with malaria infections have been documented in captive species of Sphenisciformes, Somateria, and Larosterna, all genera that evolved in climates with low mosquito exposure. To better characterize trends in Plasmodium-related mortality in a zoological collection in New York, necropsy reports for birds of all three genera that died between 1998 and February 2018 were analyzed; comparisons were made between birds that died with or without evidence of malaria infection. A seasonal peak in deaths was observed in birds regardless of their malaria status. There was no significant difference in the age of birds at death between malaria-positive and malaria-negative animals. These results suggest that age and season of death were not associated with malaria status. To investigate an association between parasite lineage and clinical outcome, polymerase chain reaction was used to identify parasite lineage in necropsied birds as well as healthy birds sampled as part of surveillance studies. Twelve different Plasmodium lineages were identified. The relative prevalence of parasite lineages was compared between necropsy and surveillance samples. A single parasite lineage, SGS1 (species: Plasmodium relictum), was significantly more likely to be found in surveillance samples; it was detected in a plurality of surveillance data but found in only one necropsy case. Other parasite lineages were more likely to be found in necropsies than in surveillance samples, most notably SEIAUR01 (species: Plasmodium cathemerium). These data may be consistent with a difference in virulence between parasite lineages. This investigation has implications for the monitoring and care of vulnerable avian species.


Assuntos
Animais de Zoológico , Charadriiformes , Patos , Malária Aviária/parasitologia , Spheniscidae , Animais , New York , Filogenia , Plasmodium/classificação , Plasmodium/isolamento & purificação
11.
Malar J ; 19(1): 69, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-32050970

RESUMO

BACKGROUND: Passerine birds are frequently infected with diverse haemosporidian parasites. While infections are traditionally considered benign in wild birds, recent studies demonstrated mortalities of passerine species due to exo-erythrocytic development of the parasites, which can damage organs in affected hosts. However, exo-erythrocytic development remains insufficiently investigated for most haemosporidian species and thus little is known about the virulence of tissue stages in wild passerine birds. The aim of the present study was to investigate natural haemosporidian infections in deceased Eurasian blackbirds (Turdus merula) and song thrushes (Turdus philomelos) and to determine parasite burden and associated histological effects. METHODS: For molecular analysis, blood and tissue samples from 306 thrushes were screened for Plasmodium, Haemoproteus and Leucocytozoon parasites by nested PCR. For the detection of parasite stages in organ samples, tissue sections were subjected to chromogenic in situ hybridization (CISH) using genus- and species-specific probes targeting the rRNAs of parasites. Exo-erythrocytic parasite burden was semi-quantitatively assessed and histological lesions were evaluated in haematoxylin-eosin-stained sections. RESULTS: By PCR, 179 of 277 Eurasian blackbirds and 15 of 29 song thrushes were positive for haemosporidians. Parasites of all three genera were detected, with Plasmodium matutinum LINN1 and Plasmodium vaughani SYAT05 showing the highest prevalence. CISH revealed significant differences in exo-erythrocytic parasite burden between lineages in Eurasian blackbirds, with P. matutinum LINN1 frequently causing high exo-erythrocytic parasite burdens in various organs that were associated with histological alterations. Song thrushes infected with P. matutinum LINN1 and birds infected with other haemosporidian lineages showed mostly low exo-erythrocytic parasite burdens. Two Eurasian blackbirds infected with Leucocytozoon sp. TUMER01 showed megalomeronts in various organs that were associated with inflammatory reactions and necroses. CONCLUSION: This study suggests that P. matutinum LINN1, a common lineage among native thrushes, regularly causes high exo-erythrocytic parasite burdens in Eurasian blackbirds, which may result in disease and mortalities, indicating its high pathogenic potential. The findings further illustrate that the same parasite lineage may show different levels of virulence in related bird species which should be considered when assessing the pathogenicity of haemosporidian parasite species. Finally, the study provides evidence of virulent Leucocytozoon sp. TUMER01 infections in two Eurasian blackbirds caused by megalomeront formation.


Assuntos
Doenças das Aves/parasitologia , Haemosporida/fisiologia , Infecções Protozoárias em Animais/parasitologia , Aves Canoras/parasitologia , Animais , Animais Selvagens , Áustria , Bolsa de Fabricius/parasitologia , DNA de Protozoário/genética , DNA de Protozoário/isolamento & purificação , Haemosporida/genética , Haemosporida/isolamento & purificação , Haemosporida/patogenicidade , Coração/parasitologia , Hibridização In Situ/métodos , Hibridização In Situ/veterinária , Rim/parasitologia , Plasmodium/classificação , Plasmodium/genética , Plasmodium/isolamento & purificação , Reação em Cadeia da Polimerase/veterinária , Especificidade da Espécie , Virulência
12.
Malar J ; 19(1): 84, 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-32085711

RESUMO

BACKGROUND: Malaria continues to affect over 200 million individuals every year, especially children in Africa. Rapid and sensitive detection and identification of Plasmodium parasites is crucial for treating patients and monitoring of control efforts. Compared to traditional diagnostic methods such as microscopy and rapid diagnostic tests (RDTs), DNA based methods, such as polymerase chain reaction (PCR) offer significantly higher sensitivity, definitive discrimination of Plasmodium species, and detection of mixed infections. While PCR is not currently optimized for routine diagnostics, its role in epidemiological studies is increasing as the world moves closer toward regional and eventually global malaria elimination. This study demonstrates the field use of a novel, ambient temperature-stabilized, multiplexed PCR assay in a small hospital setting in Sierra Leone. METHODS: Blood samples from 534 febrile individuals reporting to a hospital in Bo, Sierra Leone, were tested using three methods: a commercial RDT, microscopy, and a Multiplex Malaria Sample Ready (MMSR) PCR designed to detect a universal malaria marker and species-specific markers for Plasmodium falciparum and Plasmodium vivax. A separate PCR assay was used to identify species of Plasmodium in samples in which MMSR detected malaria, but was unable to identify the species. RESULTS: MMSR detected the presence of any malaria marker in 50.2% of all tested samples with P. falciparum identified in 48.7% of the samples. Plasmodium vivax was not detected. Testing of MMSR P. falciparum-negative/universal malaria-positive specimens with a panel of species-specific PCRs revealed the presence of Plasmodium malariae (n = 2) and Plasmodium ovale (n = 2). The commercial RDT detected P. falciparum in 24.6% of all samples while microscopy was able to detect malaria in 12.8% of tested specimens. CONCLUSIONS: Wider application of PCR for detection of malaria parasites may help to fill gaps existing as a result of use of microscopy and RDTs. Due to its high sensitivity and specificity, species coverage, room temperature stability and relative low complexity, the MMSR assay may be useful for detection of malaria and epidemiological studies especially in low-resource settings.


Assuntos
Malária/epidemiologia , Reação em Cadeia da Polimerase Multiplex/métodos , Plasmodium/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo Real/métodos , Adolescente , Adulto , Criança , Pré-Escolar , Testes Diagnósticos de Rotina , Feminino , Humanos , Masculino , Microscopia , Pessoa de Meia-Idade , Prevalência , Sensibilidade e Especificidade , Serra Leoa/epidemiologia , Adulto Jovem
13.
J Trop Pediatr ; 66(4): 428-434, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31951264

RESUMO

Diagnosis of congenital malaria is complicated by the low density of the parasite circulating in the cord blood and/or the peripheral blood of the newborns. Molecular techniques are significantly more sensitive than blood smears in detecting low-level parasitemia. This study investigated the prevalence of congenital malaria by the use of the real-time polymerase chain reaction (real-time PCR) in 102 babies born to mothers with microscopically confirmed infected placenta from Blue Nile state, Sudan. At delivery time, placental, maternal peripheral and cord blood samples in addition to samples collected from the newborns' peripheral blood were examined for malaria infection using Giemsa-stained thick smear and parasite DNA detection by real-time PCR. The overall prevalence of congenital malaria includes the total babies with cord blood parasitaemia and peripheral blood parasitaemia was 18.6 and 56.8% using microscopy and real-time PCR, respectively. Even though all the neonates were aparasitaemic by microscopy, 19 (18.6%) of the babies had congenital malaria detected by real-time PCR, 15 (25.9%) of the babies with congenital malaria were born to mothers with both placental and peripheral blood malaria infections detected using the two techniques. Congenital malaria was significantly associated with cord blood malaria infections, maternal age and maternal haemoglobin level (p < 0.001). This first study investigating congenital malaria in Blue Nile state, Sudan shows that malaria-infected placenta resulted in infant and cord blood infections.


Assuntos
Sangue Fetal/parasitologia , Malária/congênito , Placenta/parasitologia , Plasmodium/genética , Complicações Parasitárias na Gravidez/diagnóstico , Adulto , Estudos Transversais , Feminino , Humanos , Recém-Nascido , Transmissão Vertical de Doença Infecciosa , Malária/sangue , Malária/diagnóstico , Malária/epidemiologia , Masculino , Idade Materna , Mães , Parasitemia/epidemiologia , Plasmodium/classificação , Plasmodium/isolamento & purificação , Gravidez , Complicações Parasitárias na Gravidez/sangue , Complicações Parasitárias na Gravidez/epidemiologia , Prevalência , Estudos Prospectivos , Reação em Cadeia da Polimerase em Tempo Real , Sudão/epidemiologia
14.
Malar J ; 19(1): 28, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31948448

RESUMO

BACKGROUND: The sensitivity of rapid diagnostic tests (RDTs) for malaria is inadequate for detecting low-density, often asymptomatic infections, such as those that can occur when screening pregnant women for malaria. The performance of the Alere™ Ultra-sensitive Malaria Ag Plasmodium falciparum RDT (uRDT) was assessed retrospectively in pregnant women in Indonesia. METHODS: The diagnostic performance of the uRDT and the CareStart™ Malaria HRP2/pLDH VOM (Plasmodium vivax, Plasmodium ovale and Plasmodium malariae) Combo RDT (csRDT) were assessed using 270 stored red blood cell pellets and plasma samples from asymptomatic pregnant women. These included 112 P. falciparum negative and 158 P. falciparum positive samples detected by a composite test (qPCR, LAMP, nPCR) as reference standard. Diagnostic indicators: sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), diagnostic odds ratio (DOR) and the level of agreement (kappa) were calculated for comparison. RESULTS: Compared with the reference test, the uRDT had a sensitivity of 19.6% (95% CI 13.9-26.8) and specificity of 98.2% (93.1-99.7%). The csRDT was 22.8% (16.7-30.3) sensitive and 95.5% (89.4-98.3) specific for P. falciparum infections. Performance of the uRDT was non-significantly different to the csRDT (p = 0.169). RDT outcome was stratified by qPCR cycling threshold (Ct), and performance of the RDTs was found to be comparable across parasite loads. CONCLUSION: The uRDT performed similarly to the currently used csRDTs in detecting P. falciparum infections in asymptomatic pregnant women. In these settings, molecular diagnostics are currently the most sensitive for malaria.


Assuntos
Programas de Triagem Diagnóstica/normas , Malária Falciparum/diagnóstico , Complicações Parasitárias na Gravidez/diagnóstico , Coinfecção/diagnóstico , DNA de Protozoário/análise , DNA de Protozoário/sangue , DNA de Protozoário/isolamento & purificação , Eritrócitos/parasitologia , Feminino , Humanos , Indonésia , Razão de Chances , Plasmodium/genética , Plasmodium/imunologia , Plasmodium/isolamento & purificação , Valor Preditivo dos Testes , Gravidez , Estudos Retrospectivos , Sensibilidade e Especificidade
15.
BMC Res Notes ; 13(1): 37, 2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-31959229

RESUMO

OBJECTIVE: Acute kidney injury (AKI) is a frequent presentation in malaria infections. Several cases of AKI that are accompanied by clinical symptoms of malaria infection, such as fever, nausea, respiratory distress, and anemia remain undiagnosed due to challenges in accurate diagnosis using peripheral blood microscopy and rapid diagnostic tests that are currently used in clinical settings. This is particularly true for P. vivax and P. knowlesi infections. As a result, these patients are not able to receive anti-malarial therapy in a timely manner. The objective of the present study was to investigate if patients presenting with AKI harbored any of the five human Plasmodium species (P. falciparum, P. vivax, P. knowlesi, P. malariae, and P. ovale) within their renal tissues. RESULTS: We found that renal biopsies from malaria associated AKI patients harbor the human malaria parasites P. falciparum, P. vivax and P. knowlesi as mono- and mixed species infections. Presence of microvascular injury in a majority of the malaria associated AKI cases suggested vascular involvement of P. vivax and P. knowlesi. This research note also highlights P. knowlesi as an emerging pathogen in the Indian subcontinent.


Assuntos
Lesão Renal Aguda/parasitologia , Rim/parasitologia , Malária/parasitologia , Plasmodium/isolamento & purificação , Biópsia , Estudos de Casos e Controles , Índia , Rim/patologia , Malária/diagnóstico , Malária/epidemiologia , Microscopia , Plasmodium falciparum/isolamento & purificação , Plasmodium knowlesi/isolamento & purificação , Plasmodium vivax/isolamento & purificação , Estudos Retrospectivos
16.
Med Vet Entomol ; 34(1): 17-26, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31420992

RESUMO

Vector-borne diseases often originate from wildlife and can spill over into the human population. One of the most important determinants of vector-borne disease transmission is the host preference of mosquitoes. Mosquitoes with a specialised host preference are guided by body odours to find their hosts in addition to carbon dioxide. Little is known about the role of mosquito host preference in the spillover of pathogenic agents from humans towards animals and vice versa. In the Republic of Congo, the attraction of mosquitoes to primate host odours was determined, as well as their possible role as malaria vectors, using odour-baited traps mimicking the potential hosts of mosquitoes. Most of the mosquito species caught showed a generalistic host preference. Anopheles obscurus was the most abundant Anopheles mosquito, with a generalistic host preference observed from the olfactory response and the detection of various Plasmodium parasites. Interestingly, Culex decens showed a much higher attraction towards chimpanzee odours than to human or cow odours. Human Plasmodium parasites were observed in both human and chimpanzee blood, although not in the Anopheles mosquitoes that were collected. Understanding the role of mosquito host preference for cross-species parasite transmission provides information that will help to determine the risk of spillover of vector-borne diseases.


Assuntos
Anopheles/fisiologia , Quimiotaxia , Culex/fisiologia , Odorantes , Pan troglodytes , Plasmodium/isolamento & purificação , Zoonoses/transmissão , Animais , Anopheles/parasitologia , Congo , Culex/parasitologia , Comportamento Alimentar , Malária/transmissão , Malária/veterinária , Masculino , Mosquitos Vetores/parasitologia , Mosquitos Vetores/fisiologia
17.
J Med Microbiol ; 69(3): 451-456, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31846413

RESUMO

Introduction. Co-infection of leptospirosis-malaria is not uncommon due to their overlapping geographical distribution in the tropics.Aim. This study aimed to describe and compare the demographic, clinical and laboratory features of leptospirosis-malaria co-infection (LMCI) against leptospirosis mono-infection (LMI) in Peninsular Malaysia.Methodology. Data of patients admitted to various hospitals in Peninsular Malaysia from 2011 to 2014 diagnosed with leptospirosis in our laboratory were obtained from their admission records. Co-infections with malaria were identified via blood film for malaria parasites (BFMP). Description with inferential statistics analysis and multiple logistic regressions were used to distinguish features between dual and mono-infections.Results. Of 111 leptospirosis-positive patients, 26 (23.4 %) tested positive for malaria. Co-infections were predominant among male patients with a mean age of 33 years and were prevalent among immigrant populations who had settled in high-density suburban areas. Chills and rigor with splenomegaly were the only significant distinguishing clinical features of LMCI while leukocytosis and raised transaminases were significant laboratory parameters. Only chills and rigor demonstrated a predictive value for LMCI from analysis of multiple logistic regressions. No death was attributed to co-infection in this study, in contrast to LMI (11.8 %, n=10).Conclusion. The significant prevalence of LMCI found in this study with overlapping demographic, clinical and laboratory parameters makes diagnosis of co-infection challenging. It is essential to evaluate co-infection in endemic areas. Strengthened awareness of LMCI, comprehensive diagnostic services and further prospective studies are warranted.


Assuntos
Coinfecção , Leptospira/isolamento & purificação , Leptospirose/epidemiologia , Malária/epidemiologia , Plasmodium/isolamento & purificação , Adolescente , Adulto , Demografia , Feminino , Humanos , Leptospirose/diagnóstico , Leptospirose/microbiologia , Modelos Logísticos , Malária/diagnóstico , Malária/parasitologia , Malásia/epidemiologia , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Retrospectivos , Adulto Jovem
18.
Clin Chem ; 66(1): 124-137, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31811002

RESUMO

BACKGROUND: Increasingly, demands for improved health and quality of life conflict with the realities of delivering healthcare in an environment of higher expenditures, adherence to test utilization, and patient-centered experience. Patient-centered care is commonly identified as a goal of healthcare delivery, and yet healthcare systems struggle with delivery of care to patients, often failing to identify the seriously ill and capitalize on the predictive qualities of diagnostic testing. Point-of-care (POC) testing provides access to rapid diagnosis and predictive value key to realizing patient outcomes. An evaluation of cost-effective models and the clinical impact of POC testing for clinical microbiology is needed. CONTENT: Accurate and rapid diagnostics have the potential to affect healthcare decisions to a degree well out of proportion to their cost. Contemporary healthcare models increasingly view POC testing as a mechanism for efficient deployment of healthcare. POC testing can deliver rapid diagnosis in environments where testing results can be used to direct management during patient visits and in areas where centralized laboratory testing may limit access to care. Nucleic acid assays, designed for POC testing, can match, or exceed, the sensitivity of conventional laboratory-based testing, eliminating the need for confirmation testing. Here, the goals of POC testing for microbiology, applications, and technologies, as well as outcomes and value propositions, are discussed. SUMMARY: The combination of rapid reporting, an increasing array of organisms capable of causing disease, actionable resulting, and improved patient outcomes is key in the evolution of POC testing in clinical microbiology.


Assuntos
Testes Imediatos , Enterococcus/isolamento & purificação , Humanos , Malária/diagnóstico , Malária/parasitologia , Microfluídica/instrumentação , Microfluídica/métodos , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/isolamento & purificação , Orthomyxoviridae/genética , Orthomyxoviridae/imunologia , Orthomyxoviridae/isolamento & purificação , Plasmodium/isolamento & purificação , Infecções Respiratórias/diagnóstico , Infecções Respiratórias/microbiologia , Infecções Urinárias/diagnóstico , Infecções Urinárias/microbiologia
19.
Int J Parasitol ; 50(1): 63-73, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31866311

RESUMO

Habitat change caused by deforestation can modify the interactions of many biotic and abiotic factors, and in turn influence patterns of diseases in wild birds. Whether deforestation directly or indirectly affects the prevalence of avian haemosporidian parasites through their hosts and/or vectors is still not well understood. We sampled understory bird communities (insectivorous, frugivorous, granivorous and nectarivorous birds) and mosquitoes in three habitats showing a gradient of deforestation (pristine forest, fragmented forest, and young palm oil plantation), to assess the effects of habitat changes on avian haemosporidian (Plasmodium and Haemoproteus) prevalence and its relationship to bird feeding guilds and mosquito abundance. Blood samples of 845 individual birds belonging to 85 species and 27 families were collected in the three habitat types and screened using microscopy and PCR. Plasmodium infections were detected in 136 individuals (16.09%) and varied significantly among habitat types while Haemoproteus infections were detected in 98 individuals (11.60%) and did not vary significantly among habitat types. However, the prevalence of Plasmodium and Haemoproteus in bird feeding groups varied significantly among habitats. Nectarivorous and granivorous birds had the highest Plasmodium and Haemoproteus prevalence, respectively. The abundance of mosquitoes varied significantly among habitat types and the prevalence of Plasmodium significantly and positively correlated with mosquito abundance in fragmented forest. This study highlights the importance of host and mosquito determinants in the transmission dynamics of avian Plasmodium and Haemoproteus infections following habitat changes. Selective logging favored an increase in the prevalence of Plasmodium in insectivores, the prevalence of Haemoproteus in nectarivores and the abundance of female mosquitoes while, the establishment of the palm oil plantation favored an increase in the prevalence of Plasmodium in granivores and Haemoproteus in nectarivores. Species feeding behavior is also an important determinant to consider for a better understanding of patterns of parasite infections in a changing environment.


Assuntos
Aves/parasitologia , Haemosporida/genética , Mosquitos Vetores/parasitologia , Plasmodium/genética , Animais , Doenças das Aves/parasitologia , Sangue/parasitologia , Camarões , Conservação dos Recursos Naturais , Culicidae/parasitologia , DNA de Protozoário , Haemosporida/isolamento & purificação , Filogenia , Plasmodium/isolamento & purificação , Prevalência , Floresta Úmida
20.
J Parasitol ; 105(6): 913-917, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31815596

RESUMO

Hemosporidians are a monophyletic group of protozoan parasites infecting all terrestrial vertebrate orders. Although Plasmodium is the most studied genus within the Haemosporidia, this research effort is heavily biased toward mammal and bird hosts. We screened 205 specimens of at least 18 reptile species from Brazil using a partial mitochondrial cytochrome b gene marker. Positive samples were sequenced and included in a phylogenetic assessment. Four positive PCR products matched others identified as Plasmodium using BLAST from 3 different host species, Ameiva ameiva, Tropidurus hispidus, and Hemidactylus mabouia. Recovery of similar haplotypes in the native T. hispidus and exotic H. mabouia (99.9%) indicate potential host-switching.


Assuntos
Malária/veterinária , Plasmodium/genética , Répteis/parasitologia , Animais , Teorema de Bayes , Brasil/epidemiologia , Citocromos b/genética , DNA de Protozoário/química , DNA de Protozoário/isolamento & purificação , Variação Genética , Haplótipos , Funções Verossimilhança , Lagartos/parasitologia , Malária/epidemiologia , Malária/parasitologia , Programas de Rastreamento/métodos , Programas de Rastreamento/veterinária , Filogenia , Filogeografia , Plasmodium/classificação , Plasmodium/isolamento & purificação , Reação em Cadeia da Polimerase/veterinária , Prevalência , Alinhamento de Sequência/veterinária
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