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1.
Pan Afr Med J ; 47: 101, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38766565

RESUMO

Introduction: motorcycles continue to be a popular mode of transport in Kenya. However, the related injuries cause significant morbidity and mortality and remain to be a major and neglected public health issue. This raised the crucial need for hospital preparedness in managing morbidities and in reducing mortalities. This formed the basis of this paper which aims to document the challenges and opportunities in the healthcare system in handling motorcycle accidents in a Kenyan border town in Busia County. Methods: we drew data from an exploratory qualitative study that was carried out in 2021. All six referral hospitals purposively included in the study. The study targeted a total of 25 top level facility managers as key informants on the facility level opportunities and challenges in handling motorcycle accidents. Descriptive data were analyzed using SPSS version 20. Results: the hospitals were not well prepared to handle motorcycle accidents. The major challenges were understaffing in critical care services; inadequate/lack of equipment to handle motorcycle injuries; inadequate/lack of infrastructure i.e. surgical wards, emergency rooms, inadequate space, functional theatre; lack/inadequate supplies; overstretched referral services arising from the hinge burden of motorcycle accidents in the area; inadequate specialized personnel to provide trauma/care services; mishandling of cases at the site of accident; inability of victims to pay related bills; inappropriate identification of victims at the facility; lack/inadequate on-job training. Some opportunities that currently exist include health system interventions which are not limited to employment of more professionals, improvement of infrastructure, provision of equipment and increase of budgetary allocation. Conclusion: the study reveals vast challenges that are faced by hospitals in managing patients. This calls for the government to step in and capitalize on the proposed opportunities by the health managers to be able to manage morbidities and bring down mortalities due to motorcycle accidents.


Assuntos
Acidentes de Trânsito , Motocicletas , Ferimentos e Lesões , Humanos , Quênia/epidemiologia , Ferimentos e Lesões/terapia , Ferimentos e Lesões/epidemiologia , Hospitais , Atenção à Saúde/organização & administração , Atenção à Saúde/normas , Pesquisa Qualitativa
2.
J Infect Dis ; 229(6): 1919-1925, 2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38451247

RESUMO

Current serologic tests for HIV screening and confirmation of infection present challenges to the adoption of HIV vaccines. The detection of vaccine-induced HIV-1 antibodies in the absence of HIV-1 infection, referred to as vaccine-induced seropositivity/seroreactivity, confounds the interpretation of test results, causing misclassification of HIV-1 status with potential affiliated stigmatization. For HIV vaccines to be widely adopted with high community confidence and uptake, tests are needed that are agnostic to the vaccination status of tested individuals (ie, positive only for true HIV-1 infection). Successful development and deployment of such tests will require HIV vaccine developers to work in concert with diagnostic developers. Such tests will need to match today's high-performance standards (accuracy, cost-effectiveness, simplicity) for use in vaccinated and unvaccinated populations, especially in low- and middle-income countries with high HIV burden. Herein, we discuss the challenges and strategies for developing modified serologic HIV tests for concurrent deployment with HIV vaccines.


Assuntos
Vacinas contra a AIDS , Infecções por HIV , HIV-1 , Humanos , Infecções por HIV/diagnóstico , Infecções por HIV/prevenção & controle , Vacinas contra a AIDS/imunologia , HIV-1/imunologia , Anticorpos Anti-HIV/sangue , Anticorpos Anti-HIV/imunologia , Testes Sorológicos/métodos
3.
Artigo em Inglês | AIM (África) | ID: biblio-1551897

RESUMO

Introduction: genital chlamydia, which is caused by diverse Chlamydia trachomatis genotypes, is largely asymptomatic. We aimed to identify C. trachomatis genotypes causing genital chlamydia among female sex workers attending a sex workers outreach program clinic in Nairobi, Kenya. Methods: this cross-sectional study was conducted between 18 April 2017 and 19 March 2021. Genitourinary complaints from eligible female sex workers were documented using a structured questionnaire. Endocervical swabs were collected for laboratory analysis. C. trachomatis plasmid DNA was extracted, PCR-amplified, and sequenced. Consensus sequences were generated and aligned with reference sequences to determine the C.trachomatis genotypes. Bivariate analysis was used to determine the association between genitourinary complaints and genital chlamydia. Results: endocervical swabs were collected from a total of 348 participants. Of these, 46 (13.2%) were positive for C. trachomatis. Most (297, 85.3%) of the participants presented with pelvic discharge with or without other symptoms. Fifteen (15, 4.3%) had abdominal pain and 3 (0.9%) had an itchy vulva. There was no statistically significant relationship between clinical presentation and genital chlamydia. Twenty-three samples were successfully sequenced. Each sequence was at least 90% identical to each of the 13 references C. trachomatis genotypes A, B, C, D, E, F, G, Ia, J, L1, L2, L2b and L3. Conclusion: we found no significant association between individual genitourinary complaints and genital chlamydia infection. The C. trachomatis genotypes circulating amongst female sex workers in Nairobi could be related to genotypes A, B, C, D, E, F, G, Ia, J, L1, L2, L2b, and L3.


Assuntos
Humanos , Feminino
4.
J Infect Dis ; 228(11): 1583-1591, 2023 11 28.
Artigo em Inglês | MEDLINE | ID: mdl-37592824

RESUMO

BACKGROUND: HIV poses significant challenges for vaccine development due to its high genetic mutation and recombination rates. Understanding the distribution of HIV subtypes (clades) across regions and populations is crucial. In this study, a systematic review of the past decade was conducted to characterize HIV-1/HIV-2 subtypes. METHODS: A comprehensive search was performed in PubMed, EMBASE, and CABI Global Health, yielding 454 studies from 91 countries. RESULTS: Globally, circulating recombinant forms (CRFs)/unique recombinant forms (URFs) accounted for 29% of HIV-1 strains, followed by subtype C (23%) and subtype A (17%). Among studies reporting subtype breakdowns in key populations, 62% of HIV infections among men who have sex with men (MSM) and 38% among people who inject drugs (PWIDs) were CRF/URFs. Latin America and the Caribbean exhibited a 25% increase in other CRFs (excluding CRF01_AE or CRF02_AG) prevalence between 2010-2015 and 2016-2021. CONCLUSIONS: This review underscores the global distribution of HIV subtypes, with an increasing prevalence of CRFs and a lower prevalence of subtype C. Data on HIV-2 were limited. Understanding subtype diversity is crucial for vaccine development, which need to elicit immune responses capable of targeting various subtypes. Further research is needed to enhance our knowledge and address the challenges posed by HIV subtype diversity.


Assuntos
Infecções por HIV , HIV-1 , Minorias Sexuais e de Gênero , Masculino , Humanos , Homossexualidade Masculina , HIV-1/genética , HIV-2/genética , Variação Genética , Filogenia , Prevalência , Genótipo
5.
Can J Infect Dis Med Microbiol ; 2023: 2635383, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36704099

RESUMO

Dengue encephalitis is considered as a severe but unusual clinical presentation of dengue infection. Limited molecular information is available on the neurotropism of dengue virus (DENV), highlighting the need for further research. During a dengue outbreak in Vietnam in 2013, two DENV-3 strains were isolated, in which one was isolated from cerebrospinal fluid (CSF) samples from a dengue encephalitis patient and another strain was isolated from a patient with classical dengue fever in Hai Phong, Vietnam. DENV serotype-3 (DENV-3) isolated from these samples belonged to genotype III, marking the first report of this genotype in the country at that time. Genetic variation between both strains was elucidated by using a full genome sequencing by next-generation sequencing (NGS). The infectivity of the isolated DENV-3 strains was further characterized using human and mouse neuronal cell lines. Phylogenetic analysis of the isolates demonstrated high homogeneity between the CSF-derived and serum-derived DENV-3, in which the full genome sequences of the CSF-derived DENV-3 presented a Thr-1339-Ile mutation in the nonstructural 2A (NS2A) protein. The CSF-derived DENV-3 isolate grew preferentially in human neuronal cells, with a significant proportion of cells that were positive for nonstructural 1 (NS1), nonstructural 4B (NS4B), and nonstructural 5 (NS5) antigens. These results suggest that NS2A may be a crucial region in the neuropathogenesis of DENV-3 and its growth in human neuronal cells. Taken together, our results demonstrate that a CSF-derived DENV-3 has unique infectivity characteristics for human neuronal cells, which might play a crucial role in the neuropathogenesis of DENV infection.

6.
Pan Afr Med J ; 43: 143, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36785685

RESUMO

Introduction: the use of antiretroviral (ARVs) for the management of HIV (human immunodeficiency virus) infection has resulted in a prolonged lifespan among HIV-positive individuals. Both HIV infection and ARVs treatment put this population at a greater risk of developing hypertension. The study aimed at establishing the burden of hypertension and associated factors among HIV-positive population. Methods: a cross-sectional design was employed where a total of 280 HIV-positive adults in Busia County were selected in a multi-stage sampling procedure between March and August 2020. Sociodemographic, economic and behavioral information was collected using a structured questionnaire. Anthropometric measurements were taken using standard methods while clinical data were extracted from patients´ medical records. Proportion was used to establish hypertension burden. Analyses were done using the T-test, Chi-square, and odds ratio. Results: among the 280 study participants, 194 (69.3%) were females, and 239(85.4%) over 35 years of age. Hypertensive cases were 55 (19.6%). The hypertensive group had a significantly higher mean age (52.25±10.4 vs 44.9±11.3; p=0.002), waist-to-hip ratio (0.93±0.09 vs 0.89±0.07; p=0.016), HIV duration (8.64±4.63 vs 6.86±4.04; p=0.014) and cumulative ART treatment duration (8.31±4.61 vs 6.68±3.93; p=0.018). Factors found to be significantly associated with hypertension in the bivariate analysis included age (p=0.003); family history (p=0.024); duration of alcohol intake (p=0.034); HIV duration (p=0.033) and treatment duration (p=0.043). In the multivariate analysis, only age (p=0.045) and family history (p=0.018) contributed significantly in the logistic regression model. Conclusion: the study revealed a slightly lower burden of hypertension among HIV -positive adults in Busia County. Age and family history were the factors independently associated with hypertension in this study.


Assuntos
Infecções por HIV , Hipertensão , Feminino , Adulto , Humanos , Masculino , Infecções por HIV/complicações , Infecções por HIV/epidemiologia , Infecções por HIV/tratamento farmacológico , Quênia/epidemiologia , Estudos Transversais , Hipertensão/epidemiologia , Hipertensão/tratamento farmacológico , Antirretrovirais/uso terapêutico , Fatores de Risco , Prevalência
7.
Pan Afr Med J ; 38: 335, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34046145

RESUMO

INTRODUCTION: high HIV-1 infection rates and genetic diversity especially in African population pose significant challenges in HIV-1 clinical management and drug design and development. HIV-1 is a major health challenge in Kenya and causes mortality and morbidity in the country as well as straining the healthcare system and the economy. This study sought to identify HIV-1 genetic subtypes circulating in Teso, Western Kenya which borders the Republic of Uganda. METHODS: a cross-sectional study was conducted in January 2019 to December 2019. Sequencing of the partial pol gene was carried out on 80 HIV positive individuals on antiretroviral therapy. Subtypes and recombinant forms were generated using the jumping profile hidden Markov model. Alignment of the sequences was done using ClustalW program and phylogenetic tree constructed using MEGA7 neighbor-joining method. RESULTS: sixty three samples were successful sequenced. In the analysis of these sequences, it was observed that HIV-1 subtype A1 was predominant 43 (68.3%) followed by D 8 (12.7%) and 1 (1.6%) each of C, G and B and inter-subtype recombinants A1-D 3 (4.8%), A1-B 2 (3.2%) and 1 (1.6%) each of A1-A2, A1-C, BC and BD. Phylogenetic analysis of these sequences showed close clustering of closely related and unrelated sequences with reference sequences. CONCLUSION: there was observed increased genetic diversity of HIV-1 subtypes which not only pose a challenge in disease control and management but also drug design and development. Therefore, there is need for continued surveillance to enhance future understanding of the geographical distribution and transmission patterns of the HIV epidemic.


Assuntos
Fármacos Anti-HIV/administração & dosagem , Variação Genética , Infecções por HIV/virologia , HIV-1/genética , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Estudos Transversais , Feminino , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , HIV-1/isolamento & purificação , Humanos , Lactente , Quênia/epidemiologia , Masculino , Pessoa de Meia-Idade , Filogenia , Adulto Jovem
8.
Trop Med Health ; 48: 62, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760194

RESUMO

BACKGROUND: Tsetse flies are the cyclical vectors of both human and animal diseases. Kenya's commitment to eradicate tsetse and trypanosomiasis dates to the 1980s through various control approaches which were spearheaded by the African Union. The aggressive control programmes together with climatic, land-use, and socio-economic changes immensely contributed to the reduction of African trypanosomiasis. Since 2012, Kenya has not recorded a case of human trypanosomiasis. However, African animal trypanosomiasis remains a major challenge to livestock production in 38 out of 47 counties. We aimed to determine the prevalence of tsetse flies and trypanosome infection rate and to build the capacity of small-holder livestock producers in vector control activities in Busia county. METHODS: This cross-sectional study was conducted between May 2018 and December 2018 in Busia county, a beneficiary of the previous African Union-led trypanosomiasis and tsetse control initiatives. Odour-baited biconical traps were deployed for 48 h in five sampling areas. Captured tsetse flies were analysed by microscopy for trypanosome infections. Additionally, training and field demonstrations were conducted as part of capacity building to enhance participation of small-holder livestock producers in tsetse control activities. RESULTS: A total of 94 tsetse flies mainly Glossina fuscipes fuscipes were captured from the five sampling areas. The apparent fly densities range from 0.08 to 1.55 tsetse per trap per day. Additionally, 75 biting flies mainly Stomoxys spp. were also trapped. An overall tsetse infection rate of 1.39% and 4.17% was observed for Trypanosoma congolense and Trypanosoma vivax, respectively. Regarding capacity building, a total of 26 small-holder livestock producers were trained on tsetse and trypanosomiasis control activities. Out of which, five were selected as focal persons and were further trained on integrated vector management techniques and tsetse survey methods. CONCLUSIONS: Our findings revealed the existence of trypanosome-infected tsetse flies which could potentially spread to other parts of the county. Training of small-holder livestock producers in tsetse and trypanosomiasis control activities should be supported and integrated in the county animal health and veterinary services. Given the observed low tsetse densities and trypanosome infection rates, the elimination of trypanosomiasis in Busia county is feasible.

9.
Pan Afr Med J ; 37: 311, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33654530

RESUMO

INTRODUCTION: in Kenya, about 1.5 million people are living with the Human Immunodeficiency Virus (HIV). Antiretroviral therapy aids in viral suppression. However, drug-resistance threaten the gains of the HIV infection control program. To determine the prevalence of HIV-1 drug-resistant mutations among adults on ARV therapy attending Khunyangu sub-county hospital in Busia County, Kenya, 50 blood samples were analyzed. METHODS: the samples were collected from November 2019 to January 2020 and tested for HIV-1 viral load. HIV-1 drug-resistance was analyzed through the sequencing of the HIV-1 pol gene. Generated sequences were aligned using RECall (beta v3.05) software. HIV-1 drug-resistance was determined using the Stanford University HIV database. RESULTS: females were 34 and males 16. The general prevalence of HIV-1 drug-resistance was 68%. Out of 34 participants on first-line drugs, 59.9% had mutations against these drugs and 5.9% against the second-line drugs. Out of 16 participants on second-line drugs, 43.8% had mutations against these drugs and 50% against the first-line drugs. The prevalence of mutations encoding resistance to Nucleotide reverse transcriptase inhibitors (NRTIs) were 23(46%); Non-nucleotide Reverse transcriptase inhibitors (NNRTIs), 29(58%) and protease inhibitors (PIs), 7(14%). Dual and multi-class HIV-1 drug-resistance prevalence was as follows: NRTIs + NNRTIs 16(32%); NRTIs + NNRTs + PIs 4(8%); NRTIs + PIs 1(2%). A total of 126 mutations were identified. Predominant NNRTIs mutations were K103N (15), Y181C (9), G190A (7), and H221Y (6) NRTIs, M184V (17), Y115F (5) and PIs, I54V (4). CONCLUSION: the study demonstrates a high prevalence of HIV-1 drug-resistance which calls for intervention for the strengthening of health programs.


Assuntos
Fármacos Anti-HIV/farmacologia , Farmacorresistência Viral/genética , Infecções por HIV/tratamento farmacológico , HIV-1/efeitos dos fármacos , Adolescente , Adulto , Fármacos Anti-HIV/administração & dosagem , Estudos Transversais , Feminino , Infecções por HIV/epidemiologia , Infecções por HIV/virologia , HIV-1/genética , Humanos , Quênia/epidemiologia , Masculino , Pessoa de Meia-Idade , Mutação , Prevalência , Carga Viral , Adulto Jovem
10.
Int J Infect Dis ; 91: 104-110, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31712089

RESUMO

BACKGROUND: Arboviruses often cause widespread morbidity in children in endemic regions. Data on the burden of arboviruses in Kenyan children are limited. OBJECTIVES: This study was performed to determine the seroprevalence of yellow fever (YFV), dengue (DENV), West Nile (WNV), and chikungunya (CHIKV) viruses among children 1-12 years of age at two health facilities in Teso South Sub-County in Western Kenya. METHODS: In a hospital-based cross-sectional survey, a questionnaire was used to collect socio-demographic information. Serum drawn from the children was tested for IgA/IgM/IgG serocomplex antibodies to selected arboviruses using indirect ELISA and plaque reduction neutralization tests. RESULTS: A total of 182 (27.7%) of the 656 participants tested were positive for any arbovirus antibody. Of these, 4.4% (29/656) tested positive for YFV, 9.6% (62/649) for WNV, 5.6% (36/649) for CHIKV, 1.4% (5/368) for DENV1, 9% (59/656) for DENV2, and 19.7% (40/203) for DENV3. Neutralizing antibodies to CHIKV were found in 77.8% (42/54) of participants, to YFV in 15.8% (3/19), to DENV2 in 58% (29/50), and to WNV in 8% (1/55). Sex, age, urban residence, schooling, and lack of vaccination were associated with arbovirus exposure. CONCLUSIONS: This study confirmed that children under 12 years of age in Teso South Sub-County are exposed to ongoing arbovirus infections early in life.


Assuntos
Febre de Chikungunya/epidemiologia , Dengue/epidemiologia , Febre do Nilo Ocidental/epidemiologia , Febre Amarela/epidemiologia , Anticorpos Antivirais/sangue , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Lactente , Quênia/epidemiologia , Masculino , Estudos Soroepidemiológicos
11.
Virol J ; 15(1): 178, 2018 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-30466469

RESUMO

BACKGROUND: Rift Valley Fever (RVF) is a mosquito-borne viral zoonosis. To detect RVF virus (RVFV) infection, indirect immunoglobulin G (IgG) and immunoglobulin M (IgM) enzyme linked immunosorbent assays (ELISAs) which utilize recombinant RVFV nucleocapsid (RVFV-N) protein as assay antigen, have reportedly been used, however, there is still a need to develop more sensitive and specific methods of detection. METHODS: RVFV-N protein was expressed in Escherichia coli (E. coli) and purified by histidine-tag based affinity chromatography. This recombinant RVFV-N (rRVFV-N) protein was then used as antigen to develop an IgG sandwich ELISA and IgM capture ELISAs for human sera. Ninety six serum samples collected from healthy volunteers during the RVF surveillance programme in Kenya in 2013, and 93 serum samples collected from RVF-suspected patients during the 2006-2007 RVF outbreak in Kenya were used respectively, to evaluate the newly established rRVFV-N protein-based IgG sandwich ELISA and IgM capture ELISA systems in comparison with the inactivated virus-based ELISA systems. RESULTS: rRVFV-N protein-based-IgG sandwich ELISA and IgM capture ELISA for human sera were established. Both the new ELISA systems were in 100% concordance with the inactivated virus-based ELISA systems, with a sensitivity and specificity of 100%. CONCLUSIONS: Recombinant RVFV-N is a safe and affordable antigen for RVF diagnosis. Our rRVFV-N-based ELISA systems are safe and reliable tools for diagnosis of RVFV infection in humans and especially useful in large-scale epidemiological investigation and for application in developing countries.


Assuntos
Antígenos Virais/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Proteínas do Nucleocapsídeo/imunologia , Febre do Vale de Rift/diagnóstico , Vírus da Febre do Vale do Rift/imunologia , Inativação de Vírus , Animais , Anticorpos Antivirais/sangue , Antígenos Virais/isolamento & purificação , Escherichia coli/genética , Voluntários Saudáveis , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Coelhos , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/isolamento & purificação , Febre do Vale de Rift/imunologia , Sensibilidade e Especificidade , Zoonoses/diagnóstico , Zoonoses/imunologia , Zoonoses/virologia
12.
Clin Vaccine Immunol ; 23(8): 689-97, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27307452

RESUMO

Yellow fever (YF) is an acute hemorrhagic viral infection transmitted by mosquitoes in Africa and South America. The major challenge in YF disease detection and confirmation of outbreaks in Africa is the limited availability of reference laboratories and the persistent lack of access to diagnostic tests. We used wild-type YF virus sequences to generate recombinant envelope protein in an Escherichia coli expression system. Both the recombinant protein and sucrose gradient-purified YF vaccine virus 17D (YF-17D) were used to immunize BALB/c mice to generate monoclonal antibodies (MAbs). Eight MAbs were established and systematically characterized by indirect enzyme-linked immunosorbent assay (ELISA), Western blot analysis, and immunofluorescence assay (IFA). The established MAbs showed strong reactivity with wild-type YF virus and recombinant protein with no detectable cross-reactivity to dengue virus or Japanese encephalitis virus. Epitope mapping showed strong binding of three MAbs to amino acid positions 1 to 51, while two MAbs mapped to amino acid positions 52 to 135 of the envelope protein. The remaining three MAbs did not show reactivity to envelope fragments. The established MAbs exert no neutralization against wild-type YF and 17D viruses (titer of <10 for both strains). The applicability of MAbs 8H3 and 3F4 was further evaluated using IgM capture ELISA. A total of 49 serum samples were analyzed, among which 12 positive patient and vaccinee samples were correctly identified. Using serum samples that were 2-fold serially diluted, the IgM capture ELISA was able to detect all YF-positive samples. Furthermore, MAb-based antigen detection ELISA enabled the detection of virus in culture supernatants containing titers of about 1,000 focus-forming units.


Assuntos
Anticorpos Monoclonais/isolamento & purificação , Anticorpos Antivirais/isolamento & purificação , Antígenos Virais/análise , Testes Diagnósticos de Rotina/métodos , Ensaio de Imunoadsorção Enzimática/métodos , Febre Amarela/diagnóstico , Vírus da Febre Amarela/imunologia , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Escherichia coli/genética , Escherichia coli/metabolismo , Humanos , Imunoglobulina M/sangue , Fatores Imunológicos , Camundongos Endogâmicos BALB C , Ligação Proteica , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/imunologia
13.
Virol J ; 12: 117, 2015 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-26239826

RESUMO

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging disease that was first reported in China in 2011. It is caused by SFTS virus (SFTSV) which is a member of the Phlebovirus genus in the Bunyaviridae family. SFTSV has been classified as a BSL3 pathogen. There is a need to develop safe and affordable serodiagnostic methods for proper clinical management of infected patients. METHODS: The full length nucleocapsid (N) gene of SFTSV Yamaguchi strain was amplified by RT-PCR and cloned to an expression vector pQE30. The recombinant (r) SFTSV-N protein was expressed by using Escherichia coli (E. coli) expression system and purified under native conditions. rSFTSV-N protein based indirect IgG and IgM enzyme linked immunosorbent assay (ELISA) systems were established to detect specific human IgG and IgM antibodies, respectively. One hundred fifteen serum samples from clinically suspected-SFTS patients were used to evaluate the newly established systems and the results were compared with the total antibody detecting sandwich ELISA system. RESULTS: The native form of recombinant (r) SFTSV-N protein was expressed and purified. Application of the rSFTSV-N protein based indirect IgG ELISA to the 115 serum samples showed results that perfectly matched those of the total antibody sandwich ELISA with a sensitivity and specificity of 100 %. The rSFTSV-N protein based indirect IgM ELISA missed 8 positive samples that were detected by the total antibody sandwich ELISA. The sensitivity and specificity of rSFTSV-N-IgM capture ELISA were 90.59 and 100 %, respectively. CONCLUSIONS: The rSFTSV-N protein is highly immunoreactive and a good target for use as an assay antigen in laboratory diagnosis. Its preparation is simpler in comparison with that used for the total antibody sandwich system. Our rSFTSV-N protein-based IgG and IgM ELISA systems have the advantage of distinguishing two types of antibodies and require small volume of serum sample only. They are safe to use for diagnosis of SFTS virus infection and especially fit in large-scale epidemiological investigations.


Assuntos
Ensaio de Imunoadsorção Enzimática , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Proteínas do Nucleocapsídeo/genética , Proteínas do Nucleocapsídeo/imunologia , Febre por Flebótomos/imunologia , Phlebovirus/genética , Phlebovirus/imunologia , Proteínas Recombinantes , Ensaio de Imunoadsorção Enzimática/métodos , Expressão Gênica , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Proteínas do Nucleocapsídeo/isolamento & purificação , Febre por Flebótomos/diagnóstico , Febre por Flebótomos/virologia
14.
PLoS One ; 8(6): e67612, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23825674

RESUMO

CD4+ T cell enumeration is used to determine eligibility for antiretroviral therapy (ART) and to monitor the immune status of HIV-positive patients; however, many patients do not have access to this essential diagnostic test. Introducing point of care (POC) testing may improve access. We have evaluated Alere's PIMA™, one such POC device, against conventional CD4+ testing platforms to determine its performance and validity for use in Kenya. In our hands, Alere PIMA™ had a coefficient of variability of 10.3% and of repeatability of 175.6 cells/µl. It differed from both the BD FACSCalibur™ (r(2) = 0.762, mean bias -64.8 cells/µl), and the BD FACSCount™ (r(2) = 0.874, mean bias 7.8 cells/µl). When compared to the FACSCalibur™ at a cutoff of 350 cells/µl, it had a sensitivity of 89.6% and a specificity of 86.7% in those aged 5 years and over (Kw = 0.7566). With the BD FACSCount™, it had a sensitivity of 79.4% and a specificity of 83.4% in those aged 5 years and over (Kw = 0.7790). The device also differed from PARTEC Cyflow™ (r(2) = 0.781, mean bias -24.2 cells/µl) and GUAVA™ (r(2) = 0.658, mean bias -0.3 cells/µl) platforms, which are used in some facilities in Kenya. We conclude that with refinement, Alere PIMA™ technology has potential benefits for HIV-positive patients. This study highlights the difficulty in selecting the most appropriate reference technology for technical evaluations.


Assuntos
Linfócitos T CD4-Positivos/citologia , Contagem de Células/métodos , Sistemas Automatizados de Assistência Junto ao Leito , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Quênia , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Adulto Jovem
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