Browsing by Author "Budodo, Rule"

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Detection of Rift Valley Fever Virus Interepidemic Activity in Lower Moshi area of Kilimanjaro Region, North Eastern Tanzania: A Community Survey
(Research Square, 2021-01-22) Chilongola, Jaffu; Kumalija, Medard; Budodo, Rule; Horumpende, Pius; Mkumbaye, Sixbert; Vianney, John-Mary; Mwakapuja, Richard; Mmmbaga, Blandina
Background: Rift Valley fever virus (RVFV) is a zoonotic arbovirus of public health impact infecting livestock, wildlife, and humans mainly in Africa and other parts of the world. Despite its public health importance, mechanisms of RVFV maintenance during inter-epidemic (IEPS) periods and potentially spread to new areas remain unclear.We aimed to comparatively examine exposure to RVFV and RVFV infection among humans, goats and mosquitoes in an agro-pastoral community in Lower Moshi area of Moshi rural district. Results:Results show that the male gender was related to RVFV seropositivity (χ2 = 5.351; p=0.030). Being 50 years and above was related to seropositivity (χ2=14.430; p=0.006) whereas bed net use, larger numbers of persons living in the same house (>7 persons) and RVFV seropositivity in goats were related to higher seropositivity to RVFV among humans (χ2=6.003; p=0.021, χ2=23.213; p=0.000 and 27.053; p=0.000), respectively.RVFV antibody concentrations were only marginally higher in humans without statistically significant difference [t (112) =0.526; p=0.60)]. By the use of RT-qPCR, goats exhibited the highest RVFV infection rate of 4.1%, followed by humans (2.6%), Aedes spp(2.3%), and Culex spp(1.5%). Conclusions: In the absence of RVFV infection data in areas nearby the study site, our findings suggest Lower Moshi area as a potential hotspot for RVF, posing the danger of being a source of RVFV spread to other areas. Goats had the highest infection rate, suggesting goats as important hosts in the virus maintenance during IEPs. We recommend the design and implementation of strategies that will warrant effective active surveillance of RVF through the identification of RVF hotspots for targeted control of RVF.
Genetic diversity of Plasmodium falciparum reticulocyte binding protein homologue-5, which is a potential malaria vaccine candidate: baseline data from areas of varying malaria endemicity in Mainland Tanzania
(BioMed Central, 2025-01-27) Kisambale, Angelina; Pereus, Dativa; Mandai, Salehe; Lyimo, Beatus; Bakari, Catherine; Chacha, Gervas; Mbwambo, Ruth; Moshi, Ramadhan; Petro, Daniel; Challe, Daniel; Seth, Misago; Madebe, Rashid; Budodo, Rule; Aaron, Sijenunu; Mbwambo, Daniel; Lusasi, Abdallah; Kajange, Stella; Lazaro, Samwel; Kapologwe, Ntuli; Mandara, Celine; Ishengoma, Deus
Background The limited efficacy of the two recently approved malaria vaccines, RTS,S/AS01 and R21/Matrix- M™, highlights the need for alternative vaccine candidate genes. Plasmodium falciparum Reticulocyte Binding Protein Homologue 5 (Pfrh5) is a promising malaria vaccine candidate, given its limited polymorphism, its essential role in parasite survival, a lack of immune selection pressure and higher efficacy against multiple parasites strains. This study evaluated the genetic diversity of Pfrh5 gene among parasites from regions with varying malaria transmission intensities in Mainland Tanzania, to generate baseline data for this potential malaria vaccine candidate. Methods This study utilized secondary data of 697 whole-genome sequences which were generated by the MalariaGEN Community Network. The samples which were sequenced to generated the data were collected between 2010 and 2015 from five districts within five regions of Mainland Tanzania, with varying endemicities (Morogoro-urban district in Morogoro region, Muheza in Tanga, Kigoma-Ujiji in Kigoma, Muleba in Kagera, and Nachingwea district in Lindi region). Wright's fixation index (FST), Wright’s inbreeding coefficient (Fws), Principal component analysis (PCA), nucleotide diversity (π), haplotype network, haplotype diversity (Hd), Tajima's D, and Linkage disequilibrium (LD) were used to assess the diversity of the gene. Results Of the sequences used in this study, 84.5% (n = 589/697) passed quality control and 313 (53.1%) were monoclonal (contained infections from a single strain of P. falciparum) and were used for haplotype diversity and haplotype network analysis. High within-host diversity (Fws < 0.95) was reported in Kigoma-Ujiji (60.7%), Morogoro-urban (53.1%), and Nachingwea (50.8%), while Muleba (53.9%) and Muheza (61.6%) had low within-host diversity (Fws ≥ 0.95). PCA did not show any population structure and the mean FST value was 0.015. Low nucleotide diversity values were observed across the study sites (mean π = 0.00056). A total of 27 haplotypes were observed among the 313 monoclonal samples and under-fives exhibited higher haplotype counts. The Pf3D7 was detected as Hap_1, which occurred in 16/313 (5.1%) monoclonal sequences. Negative Tajima's D values were observed among the parasite populations in all the study sites. Conclusion Low levels of polymorphism in the pfrh5 gene were observed based on low nucleotide and haplotype diversity, a lack of population structure and negative Tajima’s D values. This study provides essential data on the diversity of the Pfrh5 gene indicating that it can be considered in the development of the next generation malaria vaccines. Robust and intensive studies of this and other candidate genes are crucial to support the prioritization of the Pfrh5 gene for potential inclusion in a broadly cross-protective malaria vaccine
Prevalence of subpatent Plasmodium falciparum infections in regions with varying transmission intensities and implications for malaria elimination in Mainland Tanzania
(PMC PubMed Central, 2025-03-26) Seth, Misago; Popkin-Hall, Zachary; Madebe, Rashid; Budodo, Rule; Bakari, Catherine; Lyimo, Beatus; Giesbrecht, David; Moshi, Ramadhani; Mbwambo, Ruth; Francis, Filbert; Pereus, Dativa; Mbata, Doris; Challe, Daniel; Mandai, Salehe; Chacha, Gervas A; Kisambale, Angelina; Mbwambo, Daniel; Aaron, Sijenunu; Lusasi, Abdallah; Lazaro, Samwel; Mandara, Celine; Bailey, Jeffrey; Juliano, Jonathan; Gutman, Julie; Ishengoma, Deus
Background Subpatent Plasmodium falciparum infections, defined as infections with parasite density below the detection limit of routine malaria diagnostic tests, contribute to infectious reservoirs, sustain transmission, and cause the failure of elimination strategies in target areas. This study assessed the prevalence of subpatent P. falci parum infections and associated risk factors in 14 regions of Mainland Tanzania. Methods The study used samples randomly selected from RDT‑negative dried blood spots (DBS) (n = 2685/10,101) collected in 2021 at 100 health facilities across 10 regions of Mainland Tanzania, and four communities in four addi tional regions. The regions were selected from four transmission strata; high (five regions), moderate (three regions), low (three regions), and very low (three regions). DNA was extracted by Tween‑Chelex method, and the Pf18S rRNA gene was amplified by quantitative polymerase chain reaction (qPCR). Logistic regression analysis was used to assess the associations between age groups, sex, fever status, and transmission strata with subpatent infection status, while linear regression analysis was used to assess the association between these factors and subpatent parasite density. Results Of the selected samples, 525/2685 (19.6%) were positive by qPCR for P. falciparum, and the positivity rates varied across different regions. Under‑fives (aOR: 1.4, 95% CI 1.04–1.88; p < 0.05) from health facilities had higher odds of subpatent infections compared to other groups, while those from community surveys (aOR: 0.33, 95% CI 0.15–0.72; p = 0.005) had lower odds. Participants from very low transmission stratum had significantly lower odds of subpatent infection compared to those from high transmission stratum (aOR = 0.53, 95% CI = 0.37–0.78; p < 0.01). The log‑trans formed median parasite density (interquartile range) was 6.9 (5.8–8.5) parasites/µL, with significantly higher parasitae mia in the low transmission stratum compared to a very low one (11.4 vs 7.0 parasites/µL, p < 0.001). Conclusion Even in very low transmission settings, the prevalence of subpatent infections was 13%, and in low trans mission settings it was even higher at 29.4%, suggesting a substantial reservoir that is likely to perpetuate transmis sion but can be missed by routine malaria case management strategies. Thus, control and elimination programmes may benefit from adoption of more sensitive detection methods to ensure that a higher proportion of subpatent infections are detected.