Bernard Langat

Bio: Bernard Langat is an academic researcher from Kenya Medical Research Institute. The author has contributed to research in topics: Plasmodium berghei & Medicine. The author has an hindex of 4, co-authored 7 publications receiving 60 citations.

Choice and Sources of Antimalarial Drugs Used for Self-medication in Kisumu, Western Kenya

Abstract: Background : The choice and sources of antimalarial drugs used for self-medication has important implication to the current malaria treatment policies in Kenya. However, data on the choice of antimalarial drugs used for self-medication and their sources remains scanty. Objectives : The objectives of this study were to determine the prevalence of self-medication, the choice and sources of antimalarial drugs used for malaria self-medication in Kisumu city, Western Kenya. Methodology: This was a cross-sectional community based study, in which semi-structured questionnaires were randomly administered to 338 participants, in five administrative wards of Kisumu city. Results: Overall, 250 (74%) of the participants reported self-medication for perceived malaria illness. Of the 250 participants, 219 (87.6%) had used an antimalarial drug(s), while 31 (12.4%) took other drugs (antipyretics and herbs), which they perceived to have antimalarial effect. Artemisinin-based combination therapies (ACT), was the drug of choice for majority 154 (70.3%) of those who had self-medicated. The other antimalarials used were sulphadoxine/sulphalene-pyrimethamine 25 (11.4%), amodiaquine 11 (5%), chloroquine 5 (2.3%), quinine 2 (0.9%), dihydroartemisinin 1 (0.5%), halofantrene 1 (0.5%) and 20 (9%) of participants had used two different antimalarials. The antimalarial drugs were sourced from private pharmacies/chemists (78.4%), general retail shops (29.2%), left over drugs at home (1.6%), or friends, relatives and neighbors (2.8%). Conclusion: Self-medication for perceived malaria is prevalent in Kisumu city. ACT is the drug of choice for self-medication. However, a substantial proportion of individuals use currently ineffective antimalarials or other drugs, for example antipyretics, with no known antimalarial efficacy. Pharmacies/chemists and general retail shops are the major sources for self-prescribed drugs. Key words: Self-medication, antimalarial drugs, choices, sources

Larvicidal effect of Mundulea sericea (Leguminosaea) plant extract against Aedes aegypti (L.) (Diptera: Culicidae)

Abstract: Introduction The medical importance of mosquitoes as vectors for the transmission of serious diseases that cause morbidity, mortality, economic loss, and social disruption such as malaria, lymphatic filariasis, and viral diseases is well recorded (Becker et al, 2003). Aedes aegypti, the main carrier for viruses that cause dengue and dengue hemorrhagic and yellow fevers, is found majorly in the tropics and subtropics. There is no effective vaccine against dengue, and thus the only way of significantly lowering the incidence of this disease is through mosquito control (Malavige et al, 2004). Chemical measures were first tried, but they failed since their overuse led to disruption of natural biological control systems and outbreak of new insect species. In addition, use of insecticides led to the development of mosquito resistance, environmental pollution, and undesirable effect on non-target organisms (Brown, 1986). In a bid to resolve these problems, interest in insecticides of natural origin, specifically plant-derived products has recently received close attention. Several studies have emphasized the importance of research and development of herbal substances for controlling mosquitoes (Shaala et al, 2005). Their results may vary, but natural plant products may be a possible alternative to synthetic substances, as they are effective and compatible with human and animal life and the environment (Chaithong et al, 2006). The genus Mundulea consists of about 15 species, widespread throughout Africa, Madagascar, Mauritius, India, Sri Lanka and Papua New Guinea. Only a single species, Mundulea sericea, is found in Southern Africa. This species occurs in South Africa, Botswana, Namibia and Angola, north to tropical Africa, and east to Madagascar, India, Sri Lanka and Papua New Guinea (Watt and Breyer-Brandwick, 1962). Mundulea sericea is one of the commonest fish poisons where both bark and seeds are used (Neuwinger, 2004). In addition, the Chinese used M. sericea to control tobacco budworm Heliothis virescens (Lepidopteriae: Noctuidae) (Yoshida and Toscano, 1994). The toxic principal of the plant is rotenone, an isoflavonoid (Vedcourt and Trump, 1969). The rotenoids deguelin and tephrosin are the potent active principles which have been isolated from extracts of M. sericea (Luyengi et al, 1994). Deguelin is a natural plantderived rotenoid, most commonly used as an insecticide in Africa and South America (Udeani et al, 1997). Rotenoids from the bark of M. sericea have been commercially used as insecticide. These chemical compounds in the bark, leaves and seed are the active compounds responsible for the fish poison. It is reported that the strength varies geographically (Watt and Breyer-Brandwick, 1962). The current study involved extraction and evaluation of root bark and seedpod of M. sericea for larvicidal activities on Aedes aegypt.

Self-medication with anti-malarials is a common practice in rural communities of Kilosa district in Tanzania despite the reported decline of malaria

Abstract: Self-medication has been widely practiced worldwide particularly in developing countries including Tanzania. In sub-Saharan Africa high incidences of malaria have contributed to self-medication with anti-malarial drugs. In recent years, there has been a gain in malaria control, which has led to decreased malaria transmission, morbidity and mortality. Therefore, understanding the patterns of self-medication during this period when most instances of fever are presumed to be due to non-malaria febrile illnesses is important. In this study, self-medication practice was assessed among community members and information on the habit of self-medication was gathered from health workers. Twelve focus group discussions (FGD) with members of communities and 14 in-depth interviews (IDI) with health workers were conducted in Kilosa district, Tanzania. The transcripts were coded into different categories by MaxQDA software and then analysed through thematic content analysis. The study revealed that self-medication was a common practice among FGD participants. Anti-malarial drugs including sulphadoxine-pyrimethamine and quinine were frequently used by the participants for treatment of fever. Study participants reported that they visited health facilities following failure of self-medication or if there was no significant improvement after self-medication. The common reported reasons for self-medication were shortages of drugs at health facilities, long waiting time at health facilities, long distance to health facilities, inability to pay for health care charges and the freedom to choose the preferred drugs. This study demonstrated that self-medication practice is common among rural communities in the study area. The need for community awareness is emphasized for correct and comprehensive information about drawbacks associated with self-medication practices. Deliberate efforts by the government and other stakeholders to improve health care services, particularly at primary health care facilities will help to reduce self-medication practices.

Current trends of Traditional Herbal Medicine Practice in Kenya: A review

Abstract: The use of herbal medicine is increasingly finding more relevance today, especially with the recognition that we are facing more challenges in the treatment of some medical conditions such as diabetes and cancer. To date, there are not many publications or records on the traditional herbal medicine use among the various Kenyan communities despite the widespread use. There is therefore an urgent need to document traditional medicines in Kenya for future reference and research. The main objective of this review is to examine the current state of traditional herbal medicine practise in Kenya, the challenges facing the sector and the possible solutions to streamline the practice and maximize on the benefits. The method adopted in this research involved the analysis of the available records on herbal medicine in Kenya from various sources including internet and the available books. This information was then compared with those in other countries with established systems in order to establish the existing inadequacies. The various efforts to document herbal medicine incorporate into mainstream healthcare and the legal framework was also reviewed. Key words: Herbal medicine, documentation, research

Optimal control and cost-effective analysis of malaria/visceral leishmaniasis co-infection

Abstract: In this paper, a deterministic model involving the transmission dynamics of malaria/visceral leishmaniasis co-infection is presented and studied. Optimal control theory is then applied to investigate the optimal strategies for curtailing the spread of the diseases using the use of personal protection, indoor residual spraying and culling of infected reservoirs as the system control variables. Various combination strategies were examined so as to investigate the impact of the controls on the spread of the disease. And we investigated the most cost-effective strategy of all the control strategies using three approaches, the infection averted ratio (IAR), the average cost-effectiveness ratio (ACER) and incremental cost-effectiveness ratio (ICER). Our results show that the implementation of the strategy combining all the time dependent control variables is the most cost-effective control strategy. This result is further emphasized by using the results obtained from the cost objective functional, the ACER, and the ICER.

Repositioning: the fast track to new anti-malarial medicines?

Abstract: Repositioning of existing drugs has been suggested as a fast track for developing new anti-malarial agents. The compound libraries of GlaxoSmithKline (GSK), Pfizer and AstraZeneca (AZ) comprising drugs that have undergone clinical studies in other therapeutic areas, but not achieved approval, and a set of US Food and Drug Administration (FDA)-approved drugs and other bio-actives were tested against Plasmodium falciparum blood stages. Molecules were tested initially against erythrocytic co-cultures of P. falciparum to measure proliferation inhibition using one of the following methods: SYBR®I dye DNA staining assay (3D7, K1 or NF54 strains); [3H] hypoxanthine radioisotope incorporation assay (3D7 and 3D7A strain); or 4’,6-diamidino-2-phenylindole (DAPI) DNA imaging assay (3D7 and Dd2 strains). After review of the available clinical pharmacokinetic and safety data, selected compounds with low μM activity and a suitable clinical profile were tested in vivo either in a Plasmodium berghei four-day test or in the P. falciparum Pf3D70087/N9 huSCID ‘humanized’ mouse model. Of the compounds included in the GSK and Pfizer sets, 3.8% (9/238) had relevant in vitro anti-malarial activity while 6/100 compounds from the AZ candidate drug library were active. In comparison, around 0.6% (24/3,800) of the FDA-approved drugs and other bio-actives were active. After evaluation of available clinical data, four investigational drugs, active in vitro were tested in the P. falciparum humanized mouse model: UK-112,214 (PAF-H1 inhibitor), CEP-701 (protein kinase inhibitor), CEP-1347 (protein kinase inhibitor), and PSC-833 (p-glycoprotein inhibitor). Only UK-112,214 showed significant efficacy against P. falciparum in vivo, although at high doses (ED90 131.3 mg/kg [95% CI 112.3, 156.7]), and parasitaemia was still present 96 hours after treatment commencement. Of the six actives from the AZ library, two compounds (AZ-1 and AZ-3) were marginally efficacious in vivo in a P. berghei model. Repositioning of existing therapeutics in malaria is an attractive proposal. Compounds active in vitro at μM concentrations were identified. However, therapeutic concentrations may not be effectively achieved in mice or humans because of poor bio-availability and/or safety concerns. Stringent safety requirements for anti-malarial drugs, given their widespread use in children, make this a challenging area in which to reposition therapy.