West Pokot District Research Articles

Factors Influencing Teacher’s Employees, Turnover in West Pokot District, Kenya

Factors Influencing Teacher’s Employees, Turnover in West Pokot District, Kenya

Prevalence of Tick-Borne Infections in Extensive Cattle Management System in West Pokot District, Kenya

Prevalence of Tick-Borne Infections in Extensive Cattle Management System in West Pokot District, Kenya

Epidemiology and Risk Factors for Serogroup X Meningococcal Meningitis during an Outbreak in Western Kenya, 2005–2006

The epidemiology of serogroup X meningococcal meningitis in Africa is unknown. During a serogroup X meningococcus outbreak in Kenya, case finding involved record review at health facilities and interviews with health workers and community leaders in West Pokot district. An age- and location-matched case-control study for risk factors was done. From December 2005 to April 2006, 82 suspect cases of meningitis were reported; the epidemic threshold was surpassed within two administrative divisions. Most (58%) cases were 5-24 years old; the case-fatality ratio was 21%. Serogroup X meningococcus was the most common serogroup - 5 (63%) of eight isolates serogrouped. Living in the same compound as another case, preceding upper respiratory tract infection and cooking outside the house were significant risk factors for disease. Serogroup X meningococcus caused an outbreak with similar epidemiology and risk factors as other serogroups. Serogroup-specific laboratory-based surveillance for meningococcus in Africa to detect serogroup X disease should be enhanced.

The irrigation system of the Pokot, northwest Kenya

Archaeological survey in the Wei wei Valley, West Pokot District, Kenya was undertaken between January 2006 and April 2007 with the aim of assessing the history and development of the indigenous, precolonial, irrigation system of the agricultural Pokot and its associated settlement pattern. Fifty-nine contemporary and thirteen abandoned irrigation furrows were mapped with GPS and oral data collected concerning their construction, management and history. Alongside this, thirteen transect surveys recording both contemporary and abandoned settlements were conducted to assess the history of the settlement pattern associated with the irrigation system. This was followed by a series of text excavations aimed at placing the settlement chronology on a more absolute footing. This paper presents the outline results of research into the irrigation system, including an assessment of its chronology of construction based on oral histories and absolute dates. Such research is imperative for better understanding the long-term nature of indigenous agronomies and developing more sustainable approaches to East African systems of production.

Serogroup X in Meningococcal Disease, Western Kenya

To the Editor: Although >12 different serogroups of Neisseria meningitidis exist, most disease outbreaks across the African meningitis epidemic belt are caused by serogroup A and, less frequently, by serogroups C and W135 (1). N. meningitidis serogroup X was first described in the 1960s and has been found to cause a few cases of invasive disease across North America, Europe, and Africa (2). In Africa, small serogroup X outbreaks have been described in Ghana (9 cases over a 2-year period) and in Niger (134 cases between 1995 and 2000) (3,4). In 2006, however, 51% of 1,139 confirmed cases of meningococcal meningitis in Niger were found to be caused by serogroup X (5). Before the 2005-06 meningococcal epidemic season, no published reports had described serogroup X isolates in East Africa. We report the involvement of N. meningitidis serogroup X in an outbreak of meningococcal disease in Western Kenya. In January 2006, the Ministry of Health of Kenya and Medecins sans Frontieres were notified of a suspected meningococcal disease outbreak in West Pokot District, bordering Uganda, in Western Kenya. On the basis of the initial outbreak investigation, the outbreak was assessed to have begun in late December 2005. Subsequent active surveillance, using the same clinical case definition of sudden fever onset with stiff neck, altered mental status, or both, showed 74 suspected cases through mid-March 2006, with a case-fatality rate of 20%. No cases were reported after March 2006. Over the course of the outbreak, cerebrospinal fluid samples were obtained from 18 patients. Due to low population density, poor access to seminomadic populations, and the limited nature of the outbreak (relatively small numbers dispersed over a wide geographic region), obtaining specimens from untreated patients in West Pokot proved difficult. Three of the 5 first samples were found to show gram-negative diplococci on staining, the next 2 were negative on Pastorex rapid latex agglutination test (Bio-Rad Laboratories, Hercules, CA, USA) (during the outbreak investigation), and a subsequent 13 were sent to the African Medical and Research Foundation (AMREF) laboratory in Nairobi, Kenya, for culture and susceptibility testing. From these 13 specimens, 2 yielded a pure growth of N. meningitidis serogroup X, while no growth was observed for the remaining 11 specimens. These 2 cultures were subsequently confirmed as serogroup X by the World Health Organization Collaborating Centre for Meningococci in Oslo, Norway. Multilocus sequence typing and sequencing of the porA and fetA genes as described (http://pubmlst.org/neisseria/), showed that the infecting strain belonged to a new sequence type, ST-5403, and that it was subtype P1.19,26 and FetA type F3-27. This sequence type is unrelated to other serogroup X isolates from Africa, including those from the latest serogroup X outbreak in Niger, but it resembles a sequence type isolated in the United States in the 1970s. In addition to the testing at AMREF and in the Oslo laboratory, the 13 samples were also analyzed by PCR at the US Naval Medical Research Unit No. 3 in Cairo, Egypt. Overall, 5 of these 13 specimens were positive for serogroup X (including the 2 samples found to be serogroup X at AMREF and confirmed by PCR in Oslo) and 1 each was positive for serogroups C, W135, and Y. At the same time as this outbreak in Western Kenya, a meningococcal meningitis outbreak was being monitored across the border in the Karamoja region of northeastern Uganda. Seminomadic populations move freely across the 2 countries, and we can assume that there was 1 meningitis outbreak that started in eastern Uganda and spread to Western Kenya. Although initial laboratory testing in Uganda suggested the presence of serogroup A, among 23 specimens subsequently sent to the Oslo laboratory, 11 were identified as serogroup X by PCR and 3 were serogroup W135 (6). Therefore, the outbreaks in both Kenya and Uganda involved multiple N. meningitidis serogroups. In West Pokot, Kenya, the Ministry of Health and Medecins sans Frontieres conducted a vaccination campaign using the trivalent polysaccharide vaccine against serogroups A, C, and W135. Before 2006, previous disease outbreaks caused by serogroup X had not reached the magnitude of those caused by serogroups A, C, or W135; they tended to evolve independently of the occurrence of both serogroups A and C and to be self-limited (3,4). Although most of Kenya is not included in the African meningitis belt, large epidemics of meningococcal disease have been reported previously (7). In conclusion, we would like to highlight the presence of N. meningitidis serogroup X in East Africa, its potential involvement in disease outbreaks, and the difficulties it may cause for laboratory confirmation and, consequently, for making an appropriate epidemic response.

Kala-azar Control, Uganda

To the Editor: Much of the leishmaniasis in Africa is concentrated in East Africa. In this region, visceral leishmaniasis (kala-azar) is caused by Leishmania donovani and is endemic in remote parts of Somalia, Sudan, Ethiopia, Kenya, and Uganda (1). In Uganda, kala-azar is transmitted by the sandfly Phlebotomus martini, and transmission is thought to be anthroponotic. Studies in Sudan and Kenya have detected L. donovani in domestic animals (2,3), but whether these play a role in Uganda is unknown. In Uganda, the disease appears to be restricted to Pokot County, a semiarid lowland area in Nakapiripirit District (Appendix Figure). This focus is an extension of a larger focus in West Pokot District in Kenya (4). The area is mainly inhabited by the Pokot, a seminomadic tribe of pastoralists. Nakapiripirit is one of the most underserved districts of Uganda, plagued by tribal clashes. Though kala-azar has been reported in East Africa since the early 1900s, it was not described in Uganda until the 1950s (5) and remained largely unnoticed until 1997, when Medecins Sans Frontieres (MSF, Swiss Section) began to provide assistance to Amudat Health Centre in Pokot County. In 2000, MSF initiated a kala-azar control program, focusing on passive case detection and treatment. From January 2000 to February 2006, a total of 3,645 patients suspected of having kala-azar were screened at Amudat Health Centre by using the direct agglutination test or rK39 antigen–based dipsticks (6); 2,088 patients with confirmed disease were treated with daily intramuscular injections of sodium stibogluconate or meglumine antimonite, 20 mg/kg bodyweight, for 30 days. Overall, 80% of the patients were <15 years of age, 75% were male, and 70% were from Kenya. From 2000 through 2005, the number of patients treated more than tripled, from 175 to 690 cases per year. Although this increase likely results, at least in part, from greater case detection due to the availability of treatment, we cannot exclude a real increase in disease because kala-azar prevalence in the area is unknown. Information on local vector behavior and risk factors for infection or disease (e.g., malnutrition and HIV coinfection) is limited, and which potential interventions are appropriate is unclear. A pilot entomologic study in 2004 (J. Stevenson, master’s thesis) demonstrated that termite mounds (Figure) are important vector breeding and resting sites and that the practice of sitting on termite mounds while guarding livestock might increase the risk for infection. In contrast, humans may be protected from kala-azar when in close proximity to livestock (i.e., because of diversion of sandflies to alternative hosts) or when lighting fires indoors (smoke acts as a repellant to most biting flies). Ownership of insecticide-treated nets, which could protect persons from sandfly bites and reduce kala-azar transmission (7), was low. Although most of the local population had heard of kala-azar, known locally as termes, and regarded it as potentially fatal, few were aware of how kala-azar is transmitted (J. Stevenson, master’s thesis). Figure A large termite mound occupies the central area of this characteristic Pokot compound. The mound provides a resting and breeding site for the sandly vector of visceral leishmaniasis. Photographer: J.H. Kolaczinski. MSF’s treatment of kala-azar is crucial because it reduces the human reservoir and hence transmission. However, current control activities only reach the tip of the iceberg: a large, underlying pool of infected and infectious persons likely exists (8,9). Kala-azar in Uganda will not likely be controlled unless the epidemiology of the disease is better understood and preventive activities are undertaken. This knowledge gap is being addressed by a partnership among the Malaria Consortium, MSF, the London School of Hygiene and Tropical Medicine, and the Vector Control Division of the Ugandan Ministry of Health. A case-control study to determine the local risk factors of kala-azar is almost completed and will be followed by seroprevalence studies in several Pokot villages, using a similar approach to recent work in the Baringo District, Kenya (9). The results will be used to formulate an integrated control strategy aimed at achieving our ultimate goal of eliminating kala-azar from Uganda.

Evaluation of Pastoral Livelihood Opportunities: a Case of West Pokot District

Evaluation of Pastoral Livelihood Opportunities: a Case of West Pokot District

Chromium Concentrations in Geobotanical Samples from West Pokot District, Kenya

The study analyses chromium concentration in plants growing around an area of chromite mineralisation, and proposes that the availability of chromium in plants could have adverse health effects when ingested by domestic animals and ultimately by the human population. This geoepidemiological attribute of geobotany has been observed in the form of chromium eczema in humans. The study was undertaken in the Sekerr Sub-location West Pokot District, which is located in the humid tropical region of the Republic of Kenya. As well as having natural vegetation cover, there are no sources of airborne pollutants in the area, which would vitiate trace element analysis in geobotanical research. The assay results show that the species Satureja abyssinica, Protea kilimandischarica, Ficus sycomorus, and Maerua subcordata have high chromium concentrations. These plants are generally browsed by domestic animals and are in turn eaten by humans. It is, therefore, proposed that a detailed analysis of chromium concentration in blood samples of both domestic animals and the human population be undertaken in order to assess its concentration levels in the population living in this geochemical environment.

A community study of child spacing, fertility and contraception in West Pokot District, Kenya

Kenya is well known for its high fertility rate and West Pokot District has the highest population growth rate in Kenya. This study was designed to examine the community's perceptions of fertility dynamics. It looks at traditional methods of family planning and the recent changes in child spacing, fertility and contraception and the attitudes behind them. This study also examines what the community (particularly women), want in the way of family planning services. The study used randomly selected groups throughout the district and employed a quasi-anthropological group discussion method.

Observations on rinderpest in Kenya, 1986-1989.

Rinderpest was confirmed in Kenya in 1986, 1987, 1988 and 1989. Three epidemiologically distinct events appear to have occurred: repeated outbreaks in West Pokot district related to cross-border movement of stock, an outbreak in Marsabit district in 1987 (thought to have been caused by illegal movement of cattle, possibly in vehicles, from countries further north) and a series of related outbreaks in and near Nairobi between 1988 and 1989 due to the unauthorized movement from abattoirs and holding grounds of slaughter stock possibly introduced from West Pokot or Marsabit. In West Pokot the disease affected unvaccinated calves and yearlings. In Marsabit cattle of all ages were affected. In August 1988, a major outbreak was confirmed in Kiambu and Kajiado districts in central Kenya, near Nairobi. At the same time a provisional diagnosis of rinderpest was made in a herd of cattle at a slaughterhouse in Nairobi. Rinderpest virus was isolated from sick cattle in all the outbreaks. Experimental infection of susceptible cattle with the Kiambu isolate demonstrated this to be of low virulence. Emergency vaccination and quarantine measures instituted immediately after confirmation eliminated clinical disease within three to four weeks in West Pokot, Kiambu and Nairobi. In Kajiado, however, the disease persisted for at least nine months, during which time a series of virus isolates was recovered. There was no evidence of infection in susceptible wildlife. This increase in the incidence of rinderpest in Kenya in recent years serves to highlight the problems of control and the need for concerted efforts to eradicate the threat of the disease from East Africa.

Saurian malaria in Kenya: Epidemiological features of malarial infections in lizard populations of the West Pokot District

During investigations into the prevalence of malarial parasites among lizards in the West Pokot District in Kenya, 179 lizards comprising eight species were caught. Examination of the Giemsa-stained smears made from their blood showed that 34 lizards were infected with Plasmodium species. Fifteen lizards were infected with a single species of Plasmodium and 19 carried multiple infections, the maximum, in four lizards, was four species. There were 19 combinations of parasite infections. Seventeen Plasmodium species were identified, the commonest being P. icipeensis. Only two of the eight lizard species were infected: the skink Mabuya striata and the agamid Agama agama. Eight of the Plasmodium species infected both; another eight species infected M. striata only but three of these have been described from different lizard families elsewhere in Africa. P. robinsoni infected A. agama only, although it was first described from another lizard family in another part of Africa. The epidemiological significance of these results is discussed.

Saurian malaria in Kenya: Description of ten new species from West Pokot District

During investigations into the epidemiology of malaria of lizards in Kenya, Giemsastained smears made from the peripheral blood, liver and spleen of hand-caught lizards from West Pokot district were examined for the presence of Plasmodium species. Ten new species were found and described. These are Plasmodium sapaaensis, P. kyaii, P. kachelibaensis, P. icipeensis, P. gloriai, P. odhiamboi, P. bowiei, P. kaninii, P. kadogoi and P. adunyinkai.

Saurian malaria in Kenya: Description of new species of haemoproteid and haemogregarine parasites, anaplasma-like and pirhemocyton-like organisms in the blood of lizards in West Pokot District

During investigations on the malaria parasites of lizards in the West Pokot district of Kenya, haemoproteids, haemogregarines, pirhemocyton-like and anaplasma-like organisms were found in the blood. Microscopic examination showed that some of these are new species and they are described in this paper. The new described species are Haemoproteus mungutii (haemoproteid), Karyolysus poleensis, Schellakia mabuyai (haemogregarines), Pirhemocyton kongelai, Haematractidium omogoi, Sauroplasma kachelibaensis (Pirhemocyton-like organisms), Eperythrozoon ngokai and Aegyptianella elgonensis (anaplasma-like organisms). K. poleensis and S. mabuyai are regarded as the first report of the genera in lizards in Africa while A. elgonensis is regarded as the first report of the genus Aegyptianella in lizards.

The Isolation of Leishmanial Parasites from Domestic Goats and Wild Hosts in Kenya and the Possible Role of Goats as Reservoirs of Leishmaniases

Screening of leishmanial parasites from domestic and wild animals was carried out in Kacheliba, West Pokot District. Spleens and livers of the animals were cultured in NNN diphasic medium. Thin smears of the same tissues were also made and stained with Giemsa stain and examined under microscope. Positive slide smears were obtained from goats and positive cultures obtained in four goats, one rat and two lizards.

Epidemiological, investigations of visceral leishmaniasis in the West Pokot District, Kenya

Studies of the epidemiology of visceral leishmaniasis in the West Pokot focus have revealed that Sergentomyia bedfordi, S. antennatus and S. schwetzi are the most abundant sandfly species. The latter have been shown to feed mainly on lizards. Phlebotomus martini was encountered in termite hills in the ventilation shafts, and showed an even distribution among the termite hills throughout the district where kala-azar cases were detected. Investigations into the relationship between termite hills and the presence of kala-azar cases in various homes were carried out. All homes afflicted with kala-azar had a termite hill or hills within a 10-m radius. The period of time spent in own homestead by each kala-azar case was to establish if each kala-azar patient contracted the disease in the focus of investigation.