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5. Tackling community undernutrition at Lake Bogoria, Kenya: The potential of Spirulina (Arthrospira fusiformis) as a food supplement

Author

C., Yin, K., Daoust, A., Young, E.J., Tebbs, and Harper, D.M.

Subjects
Food research -- Nutritional aspects -- Research, Spirulina -- Nutritional aspects -- Research, Malnutrition -- Prevention -- Research, Food supply -- Research -- Nutritional aspects, Agricultural industry, Food/cooking/nutrition, Health
Abstract

ABSTRACT [ILLUSTRATION OMITTED] Undernutrition remains a major public health concern for many developing nations, particularly in sub-Saharan Africa. In Kenya, undernutrition affects a substantial portion of the Kenyan population, especially [...]

Published
2017
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6. High concentrations of dissolved biogenic methane associated with cyanobacterial blooms in East African lake surface water

Author

Fazi S.[1, 11], Amalfitano S.[1, Venturi S.[2, Pacini N.[4, Vazquez E.[6], Olaka L.A.[7], Tassi F.[2, Crognale S.[1], Herzsprung P.[8], Lechtenfeld O.J.[8], Cabassi J.[3], Capecchiacci F.[2, Rossetti S.[1], Yakimov M.M.[9], Vaselli O.[2, Harper D.M.[5, 10], and Butturini A.[6]

Subjects
0301 basic medicine, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, Methanogenesis, QH301-705.5, Medicine (miscellaneous), Fresh Water, Cyanobacteria, 01 natural sciences, General Biochemistry, Genetics and Molecular Biology, Methane, East African Rift Valley (Kenya), Article, Gas Chromatography-Mass Spectrometry, Microbial ecology, 03 medical and health sciences, Isotopic signature, chemistry.chemical_compound, Greenhouse Gases, RNA, Ribosomal, 16S, parasitic diseases, Organic matter, Biomass, Biology (General), 0105 earth and related environmental sciences, chemistry.chemical_classification, geography, biology, Geography, Soda Lakes, Carbon cycle, biology.organism_classification, Archaea, Kenya, Lakes, 030104 developmental biology, chemistry, Environmental chemistry, geography.geographical_feature, General Agricultural and Biological Sciences, Surface water
Abstract

The contribution of oxic methane production to greenhouse gas emissions from lakes is globally relevant, yet uncertainties remain about the levels up to which methanogenesis can counterbalance methanotrophy by leading to CH4 oversaturation in productive surface waters. Here, we explored the biogeochemical and microbial community variation patterns in a meromictic soda lake, in the East African Rift Valley (Kenya), showing an extraordinarily high concentration of methane in oxic waters (up to 156 µmol L−1). Vertical profiles of dissolved gases and their isotopic signature indicated a biogenic origin of CH4. A bloom of Oxyphotobacteria co-occurred with abundant hydrogenotrophic and acetoclastic methanogens, mostly found within suspended aggregates promoting the interactions between Bacteria, Cyanobacteria, and Archaea. Moreover, aggregate sedimentation appeared critical in connecting the lake compartments through biomass and organic matter transfer. Our findings provide insights into understanding how hydrogeochemical features of a meromictic soda lake, the origin of carbon sources, and the microbial community profiles, could promote methane oversaturation and production up to exceptionally high rates., Fazi et al. report on an extraordinarily high biogenic methane concentration detected in the surface water of Lake Sonachi, Kenya. Using gas chromatography and microbiome profiling, they determine that these high concentrations are associated with cyanobacterial blooms and help provide insight to methanogenesis in meromictic soda lakes.

Published
2021
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11. Ecohydrological costs and benefits of common carp, the dominant species in a ‘novel' tropical lake ecosystem

Author

Pacini, N., Baxa, M., Kosík, M., Grey, J., Lepšová-Skácelová, O., Mbogo, D.K., Mwinami, T., Přikryl, I., Pokorný, J., Darlington, J.P.E.C., Hesslerová, P., Harper, D.M., Pacini, N., Baxa, M., Kosík, M., Grey, J., Lepšová-Skácelová, O., Mbogo, D.K., Mwinami, T., Přikryl, I., Pokorný, J., Darlington, J.P.E.C., Hesslerová, P., and Harper, D.M.

Abstract

'Novel ecosystem' is a concept which was introduced in the 21st Century to describe ecosystems heavily modified by humans, about 15 years after 'ecohydrology' had been introduced as concept within UNESCO IHP, to facilitate the sustainable management of aquatic ecosystems by humans and about 5 years after the concept of IHP 'Demonstration Sites' had been introduced to promote ecohydrological principles globally. The tropical African Lake Naivasha became a DS initially to demonstrate the importance of papyrus-dominated wetland edges for nutrient and climate control in an aquatic ecosystem driven by regional hydrological instability, but it already represented a ‘novel’ ecosystem. This paper critically examines the consequences of the aquatic food web restructuring by the major alien species, common carp (Cyprinus carpio L.) – whose arrival is directly an ecological consequence of hydrological instability. Carp were first recorded in Lake Naivasha in 2001 and reached dominance in the commercial fishery by 2003. The costs and benefits of its dominance are shown by comparing aspects of the ecosystem state before and after arrival. These were hypothesized and tested by comparing data in 2012-4 with data gathered in the 1990s using the same methodologies. Carp have filled a previously vacant benthivorous niche. The species achieved moderate density but has not caused ecological disruption. Overall, carp has been a positive contributor to the local community. More intensive management strategies, better post-harvest processing and new marketing techniques need to be developed to enhance financial gain.

Published
2021

12. Dissolved Organic Matter in Continental Hydro-Geothermal Systems: Insights from Two Hot Springs of the East African Rift Valley

Author

Butturini A.[1], Amalfitano S.[2], Herzsprung P.[3], Lechtenfeld O.J.[4], Venturi S.[5], Olaka L.A.[6], Pacini N.[7], Harper D.M.[8, Tassi F.[5, 10], and Fazi S.[2]

Subjects
Ecologia dels llacs, lcsh:Hydraulic engineering, East African Rift Valley, Geography, Planning and Development, Geochemistry, 010501 environmental sciences, Aquatic Science, 010502 geochemistry & geophysics, 01 natural sciences, Biochemistry, lcsh:Water supply for domestic and industrial purposes, Compostos orgànics, lcsh:TC1-978, East African Rift, Organic compounds, Dissolved organic carbon, Geothermal gradient, DOM, 0105 earth and related environmental sciences, Water Science and Technology, Total organic carbon, Hot spring, geography, lcsh:TD201-500, geography.geographical_feature_category, Lake ecosystem, hot springs, Kenya, Fumarole, Volcano, Environmental science, Lake ecology, FT-ICR-MS
Abstract

Little is known about the quantity and quality of dissolved organic matter (DOM) in waters from continental geothermal systems, with only a few reports available from the Yellowstone US National Park. In this study, we explored the chemodiversity of DOM in water samples collected from two geothermal hot springs from the Kenyan East African Rift Valley, a region extremely rich in fumaroles, geysers, and spouting springs, located in close proximity to volcanic lakes. The DOM characterization included in-depth assessments performed by negative electrospray ionization Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Reduced, saturated and little aromatic DOM compounds were dominant in the hot spring waters collected from either the Ol Njorowa gorge (ON) or the south shore of the soda-saline Lake Elementaita (ELM). Oxygen-poor and sulfur-bearing DOM molecules prevailed in ON, probably reflecting abiotic sulfurization from sulfide-rich geofluids. Nitrogen-bearing aliphatic and protein-like molecules were abundant in ELM, possibly perfusing through the organic-rich sediments of the adjacent Lake Elementaita. Notably, the heat-altered DOM of ancient autochthonous derivation could represent an overlooked source of aliphatic organic carbon for connected lentic environments, with a potential direct impact on nutrient cycling in lakes that receive geothermal water inputs.

Published
2020
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13. Human papillomavirus and HPV vaccines: a review/Virus du papillome humain et vaccins anti-VPH: bilan/Papilomavirus humanos y vacunas anti-PVH: revision

Author

Cutts, F.T., Franceschi, S., Goldie, S., Castellsague, X., de Sanjose, S., Garnett, G., Edmunds, W.J., Claeys, P., Goldenthal, K.L., Harper, D.M., and Markowitz, L.

Subjects
Company distribution practices, Papillomavirus infections -- Development and progression, Papillomavirus infections -- Drug therapy, Papillomavirus infections -- Risk factors, Papillomavirus infections -- Distribution, Vaccines -- Evaluation, Cervical cancer -- Causes of
Abstract

Cervical cancer, the most common cancer affecting women in developing countries, is caused by persistent infection with "high-risk" genotypes of human papillomaviruses (HPV). The most common oncogenic HPV genotypes are 16 and 18, causing approximately 70% of all cervical cancers. Types 6 and 11 do not contribute to the incidence of high-grade dysplasias (precancerous lesions) or cervical cancer, but do cause laryngeal papillomas and most genital warts. HPV is highly transmissible, with peak incidence soon after the onset of sexual activity. A quadrivalent (types 6, 11, 16 and 18) HPV vaccine has recently been licensed in several countries following the determination that it has an acceptable benefit/risk profile. In large phase III trials, the vaccine prevented 100% of moderate and severe precancerous cervical lesions associated with types 16 or 18 among women with no previous infection with these types. A bivalent (types 16 and 18) vaccine has also undergone extensive evaluation and been licensed in at least one country. Both vaccines are prepared from non-infectious, DNA-free virus-like particles produced by recombinant technology and combined with an adjuvant. With three doses administered, they induce high levels of serum antibodies in virtually all vaccinated individuals. In women who have no evidence of past or current infection with the HPV genotypes in the vaccine, both vaccines show > 90% protection against persistent HPV infection for up to 5 years after vaccination, which is the longest reported follow-up so far. Vaccinating at an age before females are exposed to HPV would have the greatest impact. Since HPV vaccines do not eliminate the risk of cervical cancer, cervical screening will still be required to minimize cancer incidence. Tiered pricing for HPV vaccines, innovative financing mechanisms and multidisciplinary partnerships will be essential in order for the vaccines to reach populations in greatest need. Le cancer du col uterin, forme la plus courante de cancer chez les femmes des pays en developpement, est due a l&apos;infection persistante par des genotypes << a haut risque >> du virus du papillome humain (PVH). Les genotypes a risque oncogene les plus courants du PVH sont les types 16 et 18, qui sont a l&apos;origine d&apos;environ 70% des cancers du col uterin. Les types 6 et 11 ne contribuent pas a l&apos;incidence des dysplasies de haut grade (lesions precancereuses) ou des cancers du col, mais sont la cause de papillomes larynges et de la plupart des condylomes acumines. Le VPH est hautement transmissible et presente un pic d&apos;incidence immediatement apres le debut de l&apos;activite sexuelle des individus. Un vaccin anti-VPH quadrivalent (contre les types 6, 11, 16 et 18) a ete recemment autorise dans plusieurs pays apres confirmation de l&apos;acceptabilite de son profil risque/benefice. Dans le cadre d&apos;essais de phase III de grande ampleur, le vaccin a prevenu 100 % des lesions cervicales precancereuses de gravite moderee et forte associees aux types 16 et 18 chez les femmes exemptes au depart d&apos;infection par ces genotypes. Un vaccin bivalent (contre les types 16 et 18) a aussi fait l&apos;objet d&apos;une evaluation complete et a ete autorise dans un pays au moins. Ces deux vaccins sont prepares a partir de particules pseudo-virales depourvues d&apos;ADN et non-infectieuses, produitespar genie genetique et associees a un adjuvant. Apres administration en trois doses, ils induisent la production de titres d&apos;anticorps seriques eleves chez presque tous les individus vaccines. Chez les femmes ne presentant aucun indice d&apos;infection anterieure ou actuelle par des VPH appartenant aux genotypes vaccinaux, ils apportent tous deux une protection de plus de 90 % contre les infections a VPH persistantes sur une periode postvaccinale allant jusqu&apos;a 5 ans (qui est aussi la plus longue duree de suivi rapportee a ce jour). L&apos;effet de la vaccination devrait etre maximal si l&apos;on vaccine la population feminine avant qu&apos;elle soit exposee aux VPH. les vaccins anti-VPH n&apos;eliminant pas le risque de cancer du col uterin, les examens de depistage de ce cancer resteront necessaires pour reduire au minimum son incidence. Pour que ces vaccins atteignent les populations qui en ont le plus besoin, il est extremement important de mettre en place une gradation des prix, des mecanismes de financement innovants et des partenariats multidisciplinaires. El cancer cervicouterino, el mas frecuente en mujeres de los paises en desarrollo, es causado por la infeccion persistente por papilomavirus humanos (PVH) de los genotipos llamados de alto riesgo. Los genotipos oncogenicos mas frecuentes son el 16 y el 18, que causan aproximadamente un 70% de los canceres cervicouterinos. Los tipos 6 y 11 no contribuyen a la incidencia de las displasias de alto grado (lesiones precancerosas) ni del cancer cervicouterino, pero causan papilomas laringeos y la mayoria de las verrugas genitales. Los PVH son muy transmisibles y su incidencia maxima se registra poco despues del inicio de la actividad sexual. Recientemente se ha aprobado en varios paises una vacuna anti-PVH tetravalente (contra/os tipos 6, 11, 16 y 18), despues de que se haya demostrado que presenta una relacion aceptable entre los riesgos y los beneficios. En los ensayos clinicos de fase III a gran escala, la vacuna evito el 100% de las lesiones cervicales precancerosas moderadas y graves asociadas a los tipos 16 y 18 en mujeres no infectadas previamente por estos tipos de PVH. Tambien se ha evaluado exhaustivamente una vacuna bivalente (contra los tipos 16 y 18) que ha sido aprobada al menos en un pais. Ambas vacunas esta preparadas con particulas no infecciosas, carentes de DNA, similares a los virus, producidas mediante tecnicas de recombinacion y combinadas con un adyuvante. Tras la administracion de tres dosis, inducen concentraciones elevadas de anticuerpos sericos en practicamente todas las personas vacunadas. En las mujeres sin infeccion pasada ni actual pot los genotipos de PVH presentes en esas vacunas, ambas proporcionan una proteccion > 90% frente a la infeccion persistente por PVH durante periodos de hasta 5 anos tras la vacunacion (el maximo tiempo de seguimiento en los estudios realizados). EI mayor impacto deberia obtenerse con la vacunacion de las mujeres antes de la edad de exposicion a los PVH. Como las vacunas anti-PVH no eliminan el riesgo de cancer cervicouterino, siguen siendo necesarias pruebas de deteccion de esta neoplasia para reducir al minimo su incidencia. Los precios diferenciales de las vacunas anti-PVH, los mecanismos de financiacion innovadores y las alianzas pluridisciplinarias serin esenciales para hacer llegar estas vacunas a las poblaciones que mas las necesitan., Introduction Cervical cancer is estimated to affect approximately 500 000 women each year, of whom 80% live in developing countries. Virtually all cervical cancer cases result from genital infection with [...]

Published
2007

14. Dissolved organic matter in continental hydro-geothermal systems: Insights from two hot springs of the East African Rift Valley

Author

Butturini, A., Amalfitano, S., Herzsprung, Peter, Lechtenfeld, Oliver, Venturi, S., Olaka, L.A., Pacini, N., Harper, D.M., Tassi, F., Fazi, S., Butturini, A., Amalfitano, S., Herzsprung, Peter, Lechtenfeld, Oliver, Venturi, S., Olaka, L.A., Pacini, N., Harper, D.M., Tassi, F., and Fazi, S.

Abstract

Little is known about the quantity and quality of dissolved organic matter (DOM) in waters from continental geothermal systems, with only a few reports available from the Yellowstone US National Park. In this study, we explored the chemodiversity of DOM in water samples collected from two geothermal hot springs from the Kenyan East African Rift Valley, a region extremely rich in fumaroles, geysers, and spouting springs, located in close proximity to volcanic lakes. The DOM characterization included in-depth assessments performed by negative electrospray ionization Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Reduced, saturated and little aromatic DOM compounds were dominant in the hot spring waters collected from either the Ol Njorowa gorge (ON) or the south shore of the soda-saline Lake Elementaita (ELM). Oxygen-poor and sulfur-bearing DOM molecules prevailed in ON, probably reflecting abiotic sulfurization from sulfide-rich geofluids. Nitrogen-bearing aliphatic and protein-like molecules were abundant in ELM, possibly perfusing through the organic-rich sediments of the adjacent Lake Elementaita. Notably, the heat-altered DOM of ancient autochthonous derivation could represent an overlooked source of aliphatic organic carbon for connected lentic environments, with a potential direct impact on nutrient cycling in lakes that receive geothermal water inputs.

Published
2020

15. Postpartum endometritis and infection following incomplete or complete abortion: Case definition & guidelines for data collection, analysis, and presentation of maternal immunization safety data

Author

Rouse, C.E. (C. E.), Eckert, L.O. (L. O.), Muñoz, F.M. (F. M.), Stringer, J.S.A. (J. S.A.), Kochhar, S. (Sonali), Bartlett, L. (L.), Sanicas, M. (M.), Dudley, D.J. (D. J.), Harper, D.M. (D. M.), Bittaye, M. (M.), Meller, L. (L.), Jehan, F. (F.), Maltezou, H.C. (H. C.), Šubelj, M. (M.), Bardaji, A. (A.), Kachikis, A. (A.), Beigi, R. (R.), Gravett, M.G. (M. G.), Rouse, C.E. (C. E.), Eckert, L.O. (L. O.), Muñoz, F.M. (F. M.), Stringer, J.S.A. (J. S.A.), Kochhar, S. (Sonali), Bartlett, L. (L.), Sanicas, M. (M.), Dudley, D.J. (D. J.), Harper, D.M. (D. M.), Bittaye, M. (M.), Meller, L. (L.), Jehan, F. (F.), Maltezou, H.C. (H. C.), Šubelj, M. (M.), Bardaji, A. (A.), Kachikis, A. (A.), Beigi, R. (R.), and Gravett, M.G. (M. G.)

Published
2019
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16. Postpartum endometritis and infection following incomplete or complete abortion: Case definition & guidelines for data collection, analysis, and presentation of maternal immunization safety data

Author

Rouse, C.E., primary, Eckert, L.O., additional, Muñoz, F.M., additional, Stringer, J.S.A., additional, Kochhar, S., additional, Bartlett, L., additional, Sanicas, M., additional, Dudley, D.J., additional, Harper, D.M., additional, Bittaye, M., additional, Meller, L., additional, Jehan, F., additional, Maltezou, H.C., additional, Šubelj, M., additional, Bardaji, A., additional, Kachikis, A., additional, Beigi, R., additional, and Gravett, M.G., additional

Published
2019
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17. Proceedings of the 16th SANCIAHS National Hydrology Symposium, University of Pretoria (Hatfield Campus), Pretoria, South Africa, 1-3 October 2012

Author

Majozi, N.P., Salama, S.M., Bernard, S., and Harper, D.M.

Subjects
Attenuation, Remote sensing, Euphotic zone, Diffusion coefficients
Abstract

Freshwater resources are losing their quality posing a threat to human and aquatic life. Remote sensing has shown potential to monitor these resources. This study aimed to retrieve diffuse attenuation coefficient (Kd), to map euphotic depth (Zeu) of Lake Naivasha, Kenya, using Medium Resolution Imaging Spectrometer (MERIS). Radiometric data was collected at Lake Naivasha. The Kd model was calibrated using in situ data and validated using MERIS 490 nm band, giving an RSME 0.43 and MAE 31%. Zeu validation gave an RSME 0.24 and MAE 20%. Atmospheric correction processors, MERIS Neural Network processors, and the ODESA software, were applied to MERIS images. Eutrophic Lakes was the most accurate at 490nm with MAE 43% and RSME 0.49. The Zeu maps show the spatio-temporal variation of Zeu, indicating the suitability of MERIS to monitor water quality of inland waters. Routine production of similar products for South African waters is currently being developed. Published

Published
2012

18. Predictors of Three Dose On-Time Compliance with HPV4 Vaccination in a Disadvantaged, Underserved, Safety Net Population in the US Midwest

Author

Verdenius, I., Harper, D.M., Harris, G.D., Griffith, R.S., Wall, J., Hempstead, L.K., Malnar, G.J., Bekkers, R.L.M., Verdenius, I., Harper, D.M., Harris, G.D., Griffith, R.S., Wall, J., Hempstead, L.K., Malnar, G.J., and Bekkers, R.L.M.

Abstract

Contains fulltext : 183582.PDF (publisher's version ) (Open Access), BACKGROUND: HPV4 is approved as a series of three timed doses expected to result in efficacy against specific HPV infections. Completion rates in the US are quite low at the same time the structure of health care delivery is changing. The aim of this study was to determine how the patient-, clinic- and systems-level characteristics facilitate or hinder the timely completion of three HPV4 doses in both adolescent and adult female populations in a high-risk safety net population. METHODS: This is a retrospective study in which patient-, clinic- and systems-level data are abstracted from the electronic medical record (EMR) for all females 10-26 years of age receiving at least one dose of HPV4 between July 1, 2006 and October 1, 2009. RESULTS: Adults were more likely to complete the three dose series if they had at least one health care visit in addition to their HPV4 visit, (aOR = 1.54 (95% CI:1.10, 2.15). Adults were less likely to complete the three dose series if they received their second HPV4 dose at an acute health care, preventive care or postpartum visits compared to an HPV4-only visit (aOR = 0.31 (95% CI: 0.13, 0.72), 0.12 (0.04, 0.35), 0.30 (0.14, 0.62), respectively). Hispanic adults were less likely than whites to complete the series (aOR = 0.24 (95% CI:0.10, 0.59). 39% of adolescents who completed two doses completed the series. CONCLUSIONS: HPV4 is more likely to be effectively administered to adults in a safety net population if multiple health care needs can be met within the health care system.

Published
2013

19. Status, ecology and conservation of an endemic fish, Oreochromis niloticus baringoensis, in Lake Baringo, Kenya

Author

Britton, J. Robert, Jackson, MC, Muchiri, M., Tarras-Wahlberg, H., Harper, D.M., Grey, Jonathan, Britton, J. Robert, Jackson, MC, Muchiri, M., Tarras-Wahlberg, H., Harper, D.M., and Grey, Jonathan

Abstract

1. The tilapia Oreochromis niloticus baringoensis is a genetically and morphologically distinct sub-species of Oreochromis niloticus endemic to Lake Baringo, Kenya. In recent years, concern has been expressed as to its status. Recent declines in catch returns suggest the population may be threatened, with conservation action required to safeguard it. 2. Catch returns from the Baringo fishery since 1964 have shown considerable fluctuations for all species, but especially O. n. baringoensis. From a peak of 712 t in 1970, their total catch was only 5 t in 2005, despite a 2 year period of closure in 2002 and 2003. Changes in fishery catch and relative abundance were independent of exploitation in the fishery but were significantly correlated with lake level. 3. Few individuals were captured at lengths >250 mm, with no fish sampled >284 mm. During periods of high lake level, individuals matured at smaller sizes and were capable of growing to larger ultimate sizes. With maturity at lengths <130 mm and fishery regulations preventing removal of fish <180 mm, there was a relatively large proportion of mature fish that was below exploitation size each year (19 to 44%). In most years, the proportion of fish available for exploitation was <10%. 4. Stable isotope analyses revealed O. n. baringoensis was reliant upon planktonic basal resources and zooplankton carbon. There was only minimal trophic overlap with other fish species in the lake, indicating little potential for competition for food resources. 5. These data suggest that the population status of O. n. baringoensis is not threatened per se, but subject to an unpredictable and unstable environment that strongly influences their life-history traits and, ultimately, their population abundance, and should be managed accordingly.

Published
2009

20. Researchers find HPV vaccine safe, effective for 4.5 years

Author

Harper, D.M., Franco, E.L., and Wheeler, C.M.

Subjects
Viral vaccines -- Usage, Papillomavirus infections -- Prevention, Cervical cancer -- Research, Health
Abstract

Three immunizations with a bivalent human papillomavirus (HPV)-16/18 L1 virus-like particle AS04 vaccine safely induces sustained high levels of antibodies that provide long-term protection against HPV-16 and -18 infection and [...]

Published
2006

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