Bio

Publications


2014

Misigo, D, Mwaengo D, Mburu D.  2014.  Molecular detection and phylogenetic analysis of Kenyan human bocavirus isolates., 2014 Feb. Journal of infection in developing countries. 8(2):221-7. Abstract

The commonly expected causative agents associated with flu-like symptoms in Kenya are the classical viral pathogens identifiable as influenza virus, adenovirus, parainfluenza virus, enteroviruses, respiratory syncytial virus (RSV) and rhinovirus. However, newer agents have been identified globally that present with illnesses clinically indistinguishable from those caused by the classical pathogens; one of them is human bocavirus.

2012

Mwaengo, D, Lorenzo G, Iglesias J, Warigia M, Sang R, Bishop RP, Brun A.  2012.  Detection and identification of Rift Valley fever virus in mosquito vectors by quantitative real-time PCR.. Virus research. 169(1):137-43. Abstract

Diagnostic methods allowing for rapid identification of pathogens are crucial for controlling and preventing dissemination after disease outbreaks as well as for use in surveillance programs. For arboviruses, detection of the presence of virus in their arthropod hosts is important for monitoring of viral activity and quantitative information is useful for modeling of transmission dynamics. In this study, molecular detection of Rift Valley fever virus (RVFV) in mosquito samples from the 2006 to 2007 East African outbreaks was performed using quantitative real-time PCR assay (qRT-PCR). Specific RVFV sequence-based primer/fluorogenic (TaqMan) probe sets were derived from the L and S RNA segments of the virus. Both primer-probe L and S segment-based combinations detected genomic RVFV sequences, with generally comparable levels of sensitivity. Viral loads from three mosquito species, Aedes mcintoshi, Aedes ochraceus and Mansonia uniformis were estimated and significant differences of between 5- and 1000-fold were detected between Ae. mcintoshi and M. uniformis using both the L and S primer-probe-based assays. The genetic relationships of the viral sequences in mosquito samples were established by partial M segment sequencing and assigned to the two previously described viral lineages defined by analysis of livestock isolates obtained during the 2006-2007 outbreak, confirming that similar viruses were present in both the vector and mammalian host. The data confirms the utility of qRT-PCR for identification and initial quantification of virus in mosquito samples during RVFV outbreaks.

2011

Thomas, TK, Masaba R, Borkowf CB, Ndivo R, Zeh C, Misore A, Otieno J, Jamieson D, Thigpen MC, Bulterys M, Slutsker L, De Cock KM, Amornkul PN, Greenberg AE, Fowler MG.  2011.  Triple-antiretroviral prophylaxis to prevent mother-to-child HIV transmission through breastfeeding--the Kisumu Breastfeeding Study, Kenya: a clinical trial.. PLoS medicine. 8(3):e1001015. Abstract

Effective strategies are needed for the prevention of mother-to-child HIV transmission (PMTCT) in resource-limited settings. The Kisumu Breastfeeding Study was a single-arm open label trial conducted between July 2003 and February 2009. The overall aim was to investigate whether a maternal triple-antiretroviral regimen that was designed to maximally suppress viral load in late pregnancy and the first 6 mo of lactation was a safe, well-tolerated, and effective PMTCT intervention.

Zeh, C, Oyaro B, Vandenhoudt H, Amornkul P, Kasembeli A, Bondo P, Mwaengo D, Thomas TK, Hart C, Laserson KF, Ondoa P, Nkengasong JN.  2011.  Performance of six commercial enzyme immunoassays and two alternative HIV-testing algorithms for the diagnosis of HIV-1 infection in Kisumu, Western Kenya.. Abstract

Performances of serological parallel and serial testing algorithms were analyzed using a combination of three ELISA and three rapid tests for the confirmation of HIV infection. Each was assessed individually for their sensitivity and specificity on a blinded panel of 769 retrospective sera of known HIV status. Western blot was used as a confirmatory assay for discordant results. Subsequently, one parallel and one serial testing algorithm were assessed on a new panel of 912 HIV-positive and negative samples. Individual evaluation of the ELISAs and rapid tests indicated a sensitivity of 100% for all assays except Uni-Gold with 99.7%. The specificities ranged from 99.1% to 99.4% for rapid assays and from 97.5% to 99.1% for ELISAs. A parallel and serial testing algorithms using Enzygnost and Vironostika, and Determine followed by Uni-Gold respectively, showed 100% sensitivity and specificity. The cost for testing 912 samples was US$4.74 and US$ 1.9 per sample in parallel and serial testing respectively. Parallel or serial testing algorithm yielded a sensitivity and specificity of 100%. This alternative algorithm is reliable and reduces the occurrence of both false negatives and positives. The serial testing algorithm was more cost effective for diagnosing HIV infections in this population.

Zeh, C, Amornkul PN, Inzaule S, Ondoa P, Oyaro B, Mwaengo DM, Vandenhoudt H, Gichangi A, Williamson J, Thomas T, De Cock KM, Hart C, Nkengasong J, Laserson. K.  2011.  Population-based biochemistry, immunologic and hematological reference values for adolescents and young adults in a rural population in Western Kenya. Abstract

There is need for locally-derived age-specific clinical laboratory reference ranges of healthy Africans in sub-Saharan Africa. Reference values from North American and European populations are being used for African subjects despite previous studies showing significant differences. Our aim was to establish clinical laboratory reference values for African adolescents and young adults that can be used in clinical trials and for patient management. A panel of 298, HIV-seronegative individuals aged 13-34 years was randomly selected from participants in two population-based cross-sectional surveys assessing HIV prevalence and other sexually transmitted infections in western Kenya. The adolescent (<18 years)-to-adults (≥ 18 years) ratio and the male-to-female ratio was 1∶1. Median and 95% reference ranges were calculated for immunohematological and biochemistry values. Compared with U.S-derived reference ranges, we detected lower hemoglobin (HB), hematocrit (HCT), red blood cells (RBC), mean corpuscular volume (MCV), neutrophil, glucose, and blood urea nitrogen values but elevated eosinophil and total bilirubin values. Significant gender variation was observed in hematological parameters in addition to T-bilirubin and creatinine indices in all age groups, AST in the younger and neutrophil, platelet and CD4 indices among the older age group. Age variation was also observed, mainly in hematological parameters among males. Applying U.S. NIH Division of AIDS (DAIDS) toxicity grading to our results, 40% of otherwise healthy study participants were classified as having an abnormal laboratory parameter (grade 1-4) which would exclude them from participating in clinical trials. Hematological and biochemistry reference values from African population differ from those derived from a North American population, showing the need to develop region-specific reference values. Our data also show variations in hematological indices between adolescent and adult males which should be considered when developing reference ranges. This study provides the first locally-derived clinical laboratory reference ranges for adolescents and young adults in western Kenya.

2009

M., DRMWAENGODUFTON.  2009.  Gallardo C, Mwaengo DM, Macharia JM, Arias M, Taracha EA, Soler A, Okoth E, Mart. JOURNAL OF ENVIRONMENTAL CHEMISTR. : VIRUS GENES Abstract
This is a generalization after my work on the projective space of dimension 4 to n.

2003

Mwaengo, DM, Lawrence PO.  2003.  A putative DNA helicase and novel oligoribonuclease in the Diachasmimorpha longicaudata entomopoxvirus (DlEPV). Abstract

Diachasmimorpha longicaudata entomopoxvirus (DlEPV) is a symbiotic entomopoxvirus (EPV) of the parasitic wasp Diachasmimorpha longicaudata. It has a double-stranded DNA genome of 250-300 kb and is >60% A-T rich. We describe ten ORFs (RI-35-1 to -10) contained within a 5.64 kb clone, RI-35, from a DlEPV EcoRI genomic library. Our goal was to identify unique motifs and compare them with others in the database, particularly those of poxviruses. Two ORFs (RI-35-1 and RI-35-7, respectively) encode putative proteins (113 aa and 219 aa) that are probably involved in regulating gene expression based on their predicted nuclear localization and the presence of SPxx motifs, leucine-zipper like sequences (113 aa), and a basic domain (219 aa). The largest gene (RI-35-3) is under the control of an intermediate/late promoter and is presumed to encode a cytoplasmic 480 aa DNA-dependent DNA helicase with conserved motifs that are characteristic of DExH helicases. Amino acid analysis of the DNA helicase sequence showed that DlEPV is close to but distinct from the Genus B EPVs. The DlEPV helicase is also distinct from that of the Diadromus pulchellus ascovirus 1a from the D. pulchellus parasitic wasp, with less than 10% amino acid identity. DlEPV encodes a 207 aa oligoribonuclease (RI-35-8) of the DEDDh family of exoribonucleases. The second largest ORF (RI-35-9) is under the control of a poxvirus early promoter and encodes a protein of 329 aa that is likely DlEPV-specific. Three ORFs (RI-35-4, -5, and -6) overlap (in the anti-sense strand) with ORFs encoding putatively important virus replication proteins (which were also under the control of intermediate promoters) and are presumably not expressed in DlEPV. These results support earlier reports that DlEPV is a member of the sub-family Entomopoxvirinae, most likely in Group C, and is the first symbiotic EPV described to date from a parasitic wasp.

Lawrence, PO, Mwaengo DM.  2003.  Sequence analysis of a putative DNA helicase and four peptides encoded by ORFs of the Diachasmimorpha longicaudata entomopoxvirus (DlEPV. Abstract

DlEPV is a symbiotic entomopoxvirus (EPV) of the parasitic wasp Diachasmimorpha longicaudata(Dl). It has a double stranded DNA genome of 250-300 kb and is >60% A-T rich. We describe five DlEPV open reading frames (ORFs) within the first 2.87 kb of the 5’ region of clone #35 (RI-35) from a DlEPV EcoRI genomic library. Our goal was to identify unique motifs and compare them with others in the database, particularly those of poxviruses, using Sequencher, PROSITE, and SwissPROT. RI-35-I encodes a putative nuclear peptide of 113 aa, contains a late promoter (TAAATG) and an early transcription stop sequence (TTTTTCT) three nucleotides downstream of the stop codon, and is likely an early/late gene. RI-35-2 is a late gene that presumably encodes a 117 aa cytoplasmic peptide and contains a leucine zipper-like sequence that is predicted to bind DNA, and is probably a transcription factor that regulates viral gene expression. RI-35-3 is a presumed DNA helicase gene whose protein of 480 aa is highly homologous to those of Melanoplus sanguinipesEPV (72%), Amsacta mooreiEPV (72%) and vaccinia virus (69%). DNA helicases unwind the DNA helix during replication and transcription. The DlEPV-encoded enzyme contains six conserved motifs that characterize helicases and is likely a member of the DEXH DNA and RNA helicases. Like its homologs, the RI-35-3 protein has a predicted cytoplasmic location and is probably an intermediate/late gene. RI-35-4 and –5 encode 81 and 106 aa respectively, and are predicted to be cytoplasmic proteins expressed during the intermediate phase of viral morphogenesis. Our results provide additional evidence that DlEPV is a member of the Entomopoxvirinae and is the first symbiotic EPV described to date. Support from the National Science Foundation grants, IBN 9514583 and 9986076 to POL is gratefully acknowledged.

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