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PubMed1999

Food habits in Kenya: the effects of change and attendant methodological problems.

Kenya, as a developing country, is in a process of transition between traditional and modern lifestyles. The population is dispersed by different ethnic, ecological and economical backgrounds. There are different food habits within the country and the traditions are influenced in different ways by modern influences, e. g. the media. The difficulties of studying food habits in such situations are described, and also the chances for nutrition studies.

Cultural Characteristics↗
PubMed1997

Dietary and environmental reconstruction with stable isotope analyses of herbivore tooth enamel from the Miocene locality of Fort Ternan, Kenya.

Tooth enamel of nine Middle Miocene mammalian herbivores from Fort Ternan, Kenya, was analyzed for delta 13C and delta 18O. The delta 18O values of the tooth enamel compared with pedogenic and diagenetic carbonate confirm the use of stable isotope analysis of fossil tooth enamel as a paleoenvironmental indicator. Furthermore, the delta 18O of tooth enamel indicates differences in water sources between some of the mammals. The delta 13C values of tooth enamel ranged from -8.6(-)-13.0/1000 which is compatible with a pure C3 diet, though the possibility of a small C4 fraction in the diet of a few of the specimens sampled is not precluded. The carbon isotopic data do not support environmental reconstructions of a Serengeti-typed wooded grassland with a significant proportion of C4 grasses. This study does not preclude the presence of C3 grasses at Fort Ternan; it is possible that C3 grasses could have had a wider geographic range if atmospheric CO2 levels were higher than the present values.

Animals↗
PubMed1999

Research on late Pliocene Oldowan sites at Kanjera South, Kenya.

The late Pliocene is notable for the appearance of two new hominid genera as well as the first archaeological sites, generally attributed to the Oldowan Industrial Complex. However, the behavioral ecology of Oldowan hominids has been little explored, particularly at sites older than 2.0 Ma. Moreover, debates on Oldowan hominid foraging ecology and behavior have centered on data from only two regions, and often from single site levels. Here we describe the preliminary results of our investigation of Oldowan occurrences at Kanjera South. These occurrences preserve the oldest known traces of hominid activity in southwestern Kenya, and unlike most of the Oldowan sites in the 2.0-2.5 Ma time interval, artefacts are found in spatial association with a well-preserved fauna. In 1996 and 1997, this project initiated the first excavation program for Kanjera South. Magneto- and biostratigraphy indicate that deposition began approximately 2.2 Ma, substantially earlier than previously thought. At Excavation 1, artefacts were found in spatial association with a taxonomically diverse faunal assemblage in Beds KS-1 and KS-2. Excavation 2 yielded a partial hippopotamus axial skeleton with artefacts in KS-3. Cores from both sites were incidentally flaked and represent a Mode I lithic technology indistinguishable from the Oldowan. Approximately 15% of the artefacts were manufactured from non-local raw materials, indicating a flow of resources into the area. Stable isotopic analysis of KS-1 and KS-2 pedogenic carbonates suggests that the Excavation 1 assemblages formed in a relatively open (>75% C4 grass) habitat. The Excavation 1 and 2 faunas contain a high proportion of equids relative to Oldowan accumulations from Bed I Olduvai Gorge, Tanzania. Beds KS-1 and KS-2 thus preserve traces of Oldowan hominid activities in a more open setting than has been previously documented.

Animals↗
PubMed1999

South Turkwel: a new pliocene hominid site in Kenya.

New fossils discovered south of the Turkwel River in northern Kenya include an associated metacarpal, capitate, hamate, lunate, pedal phalanx, mandibular fragment, and teeth. These fossils probably date to around 3.5 m.y.a. Faunal information suggests that the environment at South Turkwel was predominantly bushland. The mandibular and dental remains are fragmentary, but the postcranial fossils are informative. Comparisons with Australopithecus, modern human, chimpanzee and gorilla hand bones suggest that the Turkwel hominid was most like Australopithecus afarensis and A. africanus. Carpometacarpal articulations are intermediate between those of modern humans and African apes, suggesting enhanced gripping capabilities compared with extant apes. The hamulus was strikingly large, similar in proportion only to Neandertals and some gorillas, suggesting the presence of powerful forearms and hands. There are no indicators of adaptations to knuckle-walking or suspensory locomotion in the hand, and the pedal phalanx suggests that this hominid was habitually bipedal.

Animals↗
PubMed2001

Paleoenvironmental reconstruction of middle Miocene paleosols bearing Kenyapithecus and Victoriapithecus, Nyakach Formation, southwestern Kenya.

Paleosols in the middle Miocene (15 Ma) Nyakach Formation at Kaimogool, near Sondu, southwestern Kenya have yielded specimens of the early cercopithecoid Victoriapithecus macinnesi and the early kenyapithecine Kenyapithecus africanus, and can be used as evidence for the environmental mosaic occupied by these primates. Five distinct types of paleosols (pedotypes) are recognized in the Nyakach Formation section at Kaimogool South. The most common paleosols are reddish brown, silty calcareous profiles with blocky structure and large root traces (Ratong pedotype) which are interpreted as soils of well-drained, dry bushland or thicket (nyika). Weakly developed paleosols associated with paleochannels (Dhero pedotype) represent wooded grassland early in the ecological succession from streamside flooding. One of these paleosols has yielded a fossil flora of grasses and small-leaved dicots like those of modern semi-arid wooded grassland. Crumb structured, calcareous paleosols with iron-manganese nodules (Yom pedotype) are interpreted to represent seasonally waterlogged, wooded grassland (dambo or vlei). Thick, red clayey, calcareous paleosols with blocky ped structure and large root traces (Tut pedotype) are interpreted as soils of well-drained dry woodland. Other blocky-structured, gray to brown calcareous paleosols with iron-manganese nodules (Chido pedotype) are interpreted as soils of seasonally waterlogged, riparian dry woodland. Fossil soils, plants and gastropods are evidence of an unusually dry (300-500 mm mean annual precipitation) habitat for apes, consisting of a vegetational mosaic dominated by dry woodland, bushland and thickets with few areas of seasonally waterlogged grassland. Fossils of V. macinnesi are rare from Nyakach, but were found in paleosols representative of bushland and thicket habitats (Ratong). Fossils of the ape K. africanus were found within paleosols indicative of dry woodland (Tut). Other paleosol types representative of seasonally dry dambo grassland (Yom), colonizing grassland (Dhero) or riparian woodland (Chido) are also represented, but have not yet produced primate fossils.

Animals↗
PubMed2001

New hominids from the Lake Turkana Basin, Kenya.

New hominid fossils from the Lake Turkana Basin range in age from ca. 3.35 to ca. 1.0 Ma. Those recovered from sediments stratigraphically just above the Tulu Bor Tuff in the Lomekwi Member of the Nachukui Formation are best attributed to Australopithecus afarensis. This species is rare in Kenya, probably because of the scarcity of sediments deposited during its time span. Younger specimens are referable either to the megadont A. boisei or early Homo. Collectively the new fossils promote further understanding of morphological variation in East African Plio-Pleistocene hominids.

Animals↗
PubMedDate not supplied

Preliminary description of the Equatorius africanus partial skeleton (KNM-TH 28860) from Kipsaramon, Tugen Hills, Baringo District, Kenya.

A partial skeleton was recovered from middle Miocene Muruyur sediments near Kipsaramon in the Tugen Hills, Baringo District, Kenya. The specimen, representing much of the upper skeleton, comes from locality BPRP#122 dated between 15.58 Ma and 15.36 Ma. It is referable to the middle Miocene hominoid taxon Equatorius africanus. Preliminary descriptions of the partial skeleton are provided. While the anatomy of the wrist, thorax and hindlimb in Equatorius is similar to that of Afropithecus and Proconsul, the morphology of the new skeleton confirms earlier interpretations of greater terrestriality in Equatorius.

Animals↗
PubMedDate not supplied

Tephrostratigraphy and the Acheulian to middle stone age transition in the Kapthurin Formation, Kenya.

Sites containing Acheulian, Sangoan, Fauresmith, and Middle Stone Age artefacts occur within and below the Bedded Tuff, a widespread volcaniclastic member of the Kapthurin Formation, Kenya. The Bedded Tuff eruptive complex consists of up to twelve tephra beds, intercalated sediments, and paleosols. Two pumiceous units, high in the Bedded Tuff sequence, have been dated by(40)Ar/(39)Ar, one to 235+/-2 ka (Deino & McBrearty, 2002, Journal of Human Evolution, 42, 185-210, cf. Tallon, 1978, Geological Background to Fossil Man, pp. 361-373, Scottish Academic Press), the other to 284+/-12 ka (Deino & McBrearty, 2001), the latter now providing a minimum age estimate for all underlying archaeological sites. Bedded Tuff outcrops are correlated through field stratigraphic and electron microprobe geochemical analyses of individual beds. Bedded Tuff units show increasingly evolved composition through the stratigraphic succession, indicating that the beds are the product of intermittent eruption of a single differentiating magma system, and the chemical signatures of these beds permit the chronological ordering of archaeological sites. Our results indicate that the transition to Middle Stone Age technology occurred prior to 285 ka in this region of East Africa. The interstratification of sites containing Acheulian, Sangoan, Fauresmith, and Middle Stone Age artefacts suggests that these technologies were contemporary in a single depositional basin over the duration of the transition.

Animals↗
PubMedDate not supplied

40Ar/(39)Ar dating of the Kapthurin Formation, Baringo, Kenya.

The(40)Ar/(39)Ar radiometric dating technique has been applied to tuffs and lavas of the Kapthurin Formation in the Tugen Hills, Kenya Rift Valley. Two variants of the(40)Ar/(39)Ar technique, single-crystal total fusion (SCTF) and laser incremental heating (LIH) have been employed to date five marker horizons within the formation: near the base, the Kasurein Basalt at 0.61+/-0.04 Ma; the Pumice Tuff at 0.543+/-0.004 Ma; the Upper Kasurein Basalt at 0.552+/-0.015 Ma; the Grey Tuff at 0.509+/-0.009 Ma; and within the upper part of the formation, the Bedded Tuff at 0.284+/-0.012 Ma. The new, precise radiometric age determination for the Pumice Tuff also provides an age for the widespread Lake Baringo Trachyte, since the Pumice Tuff is the early pyroclastic phase of this voluminous trachyte eruption. These results establish the age of fossil hominids KNM-BK 63-67 and KNM-BK 8518 at approximately 0.510-0.512 Ma, a significant finding given that few Middle Pleistocene hominids are radiometrically dated. The Kapthurin hominids are thus the near contemporaries of those from Bodo, Ethiopia and Tanzania. A flake and core industry from lacustrine sediments in the lower part of the formation is constrained by new dates of 0.55-0.52 Ma, a period during which the Acheulian industry, characterized by handaxes, is known throughout East Africa. Points, typical of the Middle Stone Age (MSA), are found in Kapthurin Formation sediments now shown to date to between 0.509+/-0.009 Ma and 0.284+/-0.012 Ma. This date exceeds previous estimates for the age of the MSA elsewhere in East Africa by 49 ka, and establishes the age of Acheulian to MSA transition for the region. Evidence of the use of the Levallois technique for the manufacture of both small flakes and biface preforms, the systematic production of blades, and the use and processing of red ochre also occurs in this interval. The presence of blades and red ochre at this depth is important as blades signify a high degree of technical competence and red ochre suggests symbolic behavior.

Animals↗
PubMedDate not supplied

New cercopithecoids and a hominoid from 12.5 Ma in the Tugen Hills succession, Kenya.

The early evolutionary history of the cercopithecoids is poorly understood, primarily due to a lack of fossil material from between 15 and about 9 Ma. Cercopithecoid primate specimens from a fossil site in the Ngorora Formation of the Tugen Hills, Kenya, belong to the genus Victoriapithecus, possibly a new species. These fossils are associated with a hominoid specimen that resembles Proconsul, and another tooth of a catarrhine, also probably hominoid. The locality is BPRP#38, in the Kabasero type section of the Ngorora Formation, and well dated at 12.5 Ma. If the hominoid specimen is confirmed as Proconsul, it would be one of the most recent recorded. The relatively diverse mammal fauna from the site in some ways resembles that of Fort Ternan. The site is underlain, and not far removed in time, from one of the best fossil macro-floras in Africa, which indicates lowland rainforest conditions in this portion of the Rift Valley at 12.6 Ma.

Animals↗
PubMedDate not supplied

40Ar/(39)Ar geochronology and paleomagnetic stratigraphy of the Lukeino and lower Chemeron Formations at Tabarin and Kapcheberek, Tugen Hills, Kenya.

(40)Ar/(39)Ar single-crystal laser-fusion dating, K-Ar dating, and paleomagnetic reversal stratigraphy have been used to determine the chronostratigraphy of the Kabarnet Trachyte, Lukeino Formation, Kaparaina Basalt Formation, and Chemeron Formation at the sites of Kapcheberek (BPRP#77) and Tabarin (BPRP#77) in the Tugen Hills, Kenya. The succession ranges in age from 6.56-3.8 Ma. The upper Lukeino Formation at Kapcherberek, including the fauna from the site BPRP#76, was deposited during chron C3r and can be constrained to the interval 5.88-5.72 Ma. The Chemeron Formation at Tabarin includes at the base an ignimbrite and associated basal air-fall tuff with a combined age of 5.31+/-0.03 Ma. Sedimentary and volcaniclastic rocks of the Chemeron Formation which unconformably overlie the ignimbrite record chrons C3n.2n through C2Ar. The combined(40)Ar/(39)Ar and paleomagnetic data constrain the age of this sequence to 4.63-3.837 Ma. The age of the Tabarin mandible fragment (KNM-TH 13150) and associated fauna at site BPRP#77 in the Chemeron Formation is 4.48-4.41 Ma, marginally older than similar early hominids from Aramis, Ethiopia. Basin subsidence appears to be defining an overall accumulation rate of about 17 cm/ka over the 2.7 Ma represented at Tabarin and Kapcheberek, despite episodes of rapid accumulation and hiatuses.

Animals↗
PubMedDate not supplied

40Ar/(39)Ar dating of Chemeron Formation strata encompassing the site of hominid KNM-BC 1, Tugen Hills, Kenya.

A fossil hominid temporal bone (KNM-BC 1) from surface exposures at Baringo Paleontological Research Project site BPRP#2 in the Chemeron Formation outcropping in a tributary drainage of the Kapthurin River west of Lake Baringo, Kenya has been attributed to Homo sp. indet. K-feldspar phenocrysts from lapilli tuffs bracketing the inferred fossiliferous horizon yield single-crystal(40)Ar/(39)Ar ages of 2.456+/-0.006 and 2.393+/-0.013 Ma. These age determinations are supported by stratigraphically consistent ages on higher tuff horizons and from nearby sections. In addition, new(40)Ar/(39)Ar ages on tuffaceous units near the base and top of the formation along the Kapthurin River yield 3.19+/-0.03 and 1.60+/-0.05 Ma respectively. The base of the formation along the Kapthurin River is thus approximately 0.5 Ma younger than the uppermost Chemeron Formation strata exposed at Tabarin, 23 km to the north-northwest. The upper half of the formation along the Kapthurin River was deposited at an average rate of approximately 11 cm/ka, compared to 21-23 cm/ka at Tabarin.

Animals↗
PubMed2002

Paleosols and paleoenvironments of the middle Miocene, Maboko Formation, Kenya.

The middle Miocene (15 Ma) Maboko Formation of Maboko Island and Majiwa Bluffs, southwestern Kenya, has yielded abundant fossils of the earliest known cercopithecoid monkey (Victoriapithecus macinnesi), and of a kenyapithecine hominoid (Kenyapithecus africanus), as well as rare proconsuline (Simiolus leakeyorum, cf. Limnopithecus evansi) and oreopithecine apes (Mabokopithecus clarki, M. pickfordi), and galagids (Komba winamensis). Specific habitat preferences can be interpreted from large collections of primate fossils in different kinds of paleosols (pedotypes). Fossiliferous drab-colored paleosols with iron-manganese nodules (Yom pedotype) are like modern soils of seasonally waterlogged depressions (dambo). Their crumb structure and abundant fine root-traces, as well as scattered large calcareous rhizoconcretions indicate former vegetation of seasonally wet, wooded grassland. Other fossiliferous paleosols are evidence of nyika bushland (Ratong), and early-successional riparian woodland (Dhero). No fossils were found in Mogo paleosols interpreted as saline scrub soils. Very shallow calcic horizons (in Yom, Ratong, and Mogo paleosols) and Na-montmorillonite (in Mogo) are evidence of dry paleoclimate (300-500 mm MAP=mean annual precipitation). This is the driest paleoclimate and most open vegetation yet inferred as a habitat for any Kenyan Miocene apes or monkeys. Victoriapithecus was abundant in dambo wooded grassland (Yom) and riparian woodland (Dhero), a distribution like that of modern vervet monkeys. Kenyapithecus ranged through all these paleosols, but was the most common primate in nyika bushland paleosols (Ratong), comparable to baboons and macaques today. Mabokopithecus was virtually restricted to riparian woodland paleosols (Dhero), and Simiolus had a similar, but marginally wider, distribution. Habitat preferences of Mabokopithecus and Simiolus were like those of modern colobus monkeys and mangabeys. A single specimen of Komba was found in dambo wooded grassland paleosol (Yom), a habitat more like that of the living Senegal bushbaby than of rainforest galagids. A shift to non-forest habitats may explain the terrestrial adaptations of Victoriapithecus, basal to the cercopithecid radiation, and of Kenyapithecus, basal to the hominoid radiation. Both taxa are distinct from earlier Miocene arboreal proconsulines, oreopithecines and galagids.

Animals↗
PubMed1996

Characterization of a new Marburg virus isolated from a 1987 fatal case in Kenya.

In 1987, an isolated case of fatal Marburg disease was recognized during routine clinical haemorrhagic fever virus surveillance conducted in Kenya. This report describes the isolation and partial characterization of the new Marburg virus (strain Ravn) isolated from this case. The Ravn isolate was indistinguishable from reference Marburg virus strains by cross-neutralization testing. Virus particles and aggregates of Marburg nucleocapsid matrix in Ravn-infected vero cells, were visualized by immunoelectron microscopic techniques, and also in tissues obtained from the patient and from inoculated monkeys. The cell culture isolate produced a haemorrhagic disease typical of Marburg virus infection when inoculated into rhesus monkeys. Disease was characterized by the sudden appearance of fever and anorexia within 4 to 7 days, and death by day 11. Comparison of nucleotide sequences for portions of the glycoprotein genes of Marburg-Ravn were compared with Marburg reference strains Musoki (MUS) and Popp (POP). Nucleotide identity in this alignment between RAV and MUS is 72.3%, RAV and POP is 71%, and MUS and POP is 91.7%. Amino acid identity between RAV and MUS is 72%, RAV and POP is 67%, and MUS and POP is 93%. These data suggest that Ravn is another subtype of Marburg virus, analogous to the emerging picture of a spectrum of Ebola geographic isolates and subtypes.

Adolescent↗
PubMed1992

High-risk human papillomavirus types in cytologically normal cervical scrapes from Kenya.

Seventy-seven women with normal cervical cytology on routine visit to a family planning clinic in Nairobi, Kenya, were analysed for genital human papillomavirus (HPV) types by polymerase chain reaction (PCR). We applied a general primer pair (GP60/GP124) recognising sequences conserved among HPV types 6, 11, 16, 18, 31 and 33. Of the 77 specimens tested 15 (19.5%) proved to be positive for genital HPV. Amplification products were examined for the presence of high-risk HPV types by Slot-blot hybridization. Out of the 15 PCR-positive samples, 4 were positive for HPV 16.3 for HPV 18, while 1 contained both HPV 16 and 33. HPV DNA prevalence in this group of women from a "high-risk" area is similar to that in "low-risk" Swedish women but much lower than in cervical cancer samples from the same region.

Adult↗
PubMed1984

Besnoitia sp. from goats in Kenya.

The eyelids of goats in Kenya contained several, conspicuous white cysts which were up to 1.5 mm in size. By histological and electron microscopical studies it was confirmed that these cysts belong to the genus Besnoitia.

Animals↗
PubMed1985

Bulinus tropicus from Central Kenya acting as a host for Schistosoma bovis.

One hundred and twelve snails were collected from two habitats on the Mau Escarpment, Kenya and were provisionally identified as Bulinus tropicus from the characteristics of their shell and soft parts, chromosome number (n = 18), electrophoresis of egg protein on cellulose acetate strip and isoelectric focusing of AcP, GPI, HBDH, MDH and PGM digestive gland enzymes. Of the 55 specimens examined alive in London, 10 were infected with amphistome and schistosome larvae, 9 with amphistome larvae and the remainder were uninfected. The GPI and MDH separations of known infected snails showed two distinct areas of activity: host and parasite. Individual hamsters were exposed to schistosome cercariae emanating from each snail with a double infection (apart from one which died prematurely) and examination of the resulting adult worms showed that all were monomorphic for AcP with a band of enzyme activity at pH 6.45, characteristic of Schistosoma bovis. Examination of eggs found in two infections proved to be S. bovis in shape and size. Exposure of laboratory-bred snails of B. tropicus from the Mau Escarpment and other populations of B. tropicus proved negative. Thus, it is suggested that the presence of the amphistome infection may have a suppressive effect on the immune system of the snail, thereby allowing S. bovis to develop.

Animals↗
PubMed1990

[Cost-benefit analysis of malaria prophylaxis with mefloquine in travelers to Kenya].

With an increasing movement towards cost saving in the health sector, preventive medicine must also be judged according to its economic viability. The fact that prevention can autofinance itself is suggested by the results of a cost/benefit analysis of chemoprophylaxis of Falciparum malaria with Mefloquin among travellers in Kenya. Out of the whole group of travellers analysed by means of an interview-based test (Malpro-Study), the costs in the case of both Switzerland and the Federal German Republic were lower for those people who had undergone Mefloquin-prophylaxis than for those who had not. In this way the prophylaxis not only compensates the required outlay but also results in an overall benefit in macroeconomic terms. Therefore economically based opposition to the prophylaxis of malaria with Mefloquin for short stays in high-risk countries is not justified.

Animals↗