Johnstone Ingonga

Anti-parasitic activity and cytotoxicity of selected medicinal plants from Kenya.

Indigenous rural communities in the tropics manage parasitic diseases, like malaria and leishmaniasis, using herbal drugs. The efficacy, dosage, safety and active principles of most of the herbal preparations are not known. Extracts from 6 selected plant species, used as medicinal plants by indigenous local communities in Kenya, were screened for in vitro anti-plasmodial and anti-leishmanial activity, against 2 laboratory-adapted Plasmodium falciparum isolates (D6, CQ-sensitive and W2, CQ-resistant) and Leishmania major (IDU/KE/83=NLB-144 strain), respectively. The methanol extract of Suregada zanzibariensis leaves exhibited good anti-plasmodial activity (IC(50) 4.66+/-0.22 and 1.82+/-0.07 microg/ml for D6 and W2, respectively). Similarly, the methanol extracts of Albizia coriaria (IC(50) 37.83+/-2.11 microg/ml for D6) and Aspergillus racemosus (32.63+/-2.68 and 33.95+/-2.05 microg/ml for D6 and W2, respectively) had moderate anti-plasmodial activity. Acacia tortilis (IC(50) 85.73+/-3.36 microg/ml for W2) and Albizia coriaria (IC(50) 71.17+/-3.58 microg/ml for W2) methanol extracts and Aloe nyeriensis var kedongensis (IC(50) 87.70+/-2.98 and 67.84+/-2.12 microg/ml for D6 and W2, respectively) water extract exhibited mild anti-plasmodial activity. The rest of the extracts did not exhibit any anti-plasmodial activity. Although the leishmanicidal activity of extracts were lower than for pentosam (80%), reasonable activity was observed for Aloe nyeriensis methanol (68.4+/-6.3%), Albizia coriara water (66.7+/-5.0%), Maytenus putterlickoides methanol (60.0+/-6.23%), Asparagus racemosus methanol and water (58.3+/-8.22 and 56.8+/-6.58%, respectively), Aloe nyeriensis water (53.3+/-5.1%) and Acacia tortilis water (52.9+/-6.55%) extracts at 1000 microg/ml. Leishmania major infected macrophages treated with methanol extracts of Suregada zanzibariensis and Aloe nyeriensis var kedongensis and pentostam had infection rates of 28+/-2.11, 30+/-1.22 and 40+/-3.69%, respectively at 1000 microg/ml, indicating better anti-leishmanial activity for the extracts. The methanol extract of Albizia coriara (44.0+/-3.69%) and aqueous extracts of Asparagus racemosus (42+/-3.84%) and Acacia tortilis (44+/-5.59%) had similar activity to pentosam. Multiplication indices for Leishmania major amastigotes treated with methanol extracts of Albizia coriaria, Suregada zanzibariensis and Aloe nyeriensis var kedongensis, aqueous extract of Acacia tortilis and pentosam were 28.5+/-1.43, 29.4+/-2.15, 31.1+/-2.22, 35.9+/-3.49 and 44.0+/-3.27%, respectively, at 1000 microg/ml, confirming better anti-leishmanial activity for the extracts. Aqueous extracts of Aloe nyeriensis (46.7+/-3.28%) and Albizia coriaria (47.5+/-3.21%) had similar activity level to pentosam. The plant extracts have better inhibitory activity while pentosam has better leishmanicidal activity. All extracts exhibited very low cytotoxicity (CC(50) > 500 microg/ml) against human embryonic lung fibroblast (HELF) cells. The investigations demonstrated the efficacy and safety of some extracts of plants that are used by rural indigenous communities for the treatment of parasitic diseases.

Evaluation of the adjuvanticity of artemisinin with soluble Leishmania major antigens in BALB/c mice

Objective To determine the adjuvant potential of artemisinin with a soluble leishmanial antigen in vaccinating BALB/c mice.

A Descriptive Survey on Knowledge, Attitude, Practices and Beliefs (KAPBs) on Kala-azar among the Residents of Marigat Sub-County, Baringo County -

ABSTRACT Objective: To establish the level of knowledge, attitude, practices and beliefs (KAPBs) related to kala-azar among residents of Marigat sub- County, Baringo County. Methods: The sub- County is divided into 37 sub-locations and of these 8 herein referred to as villages were considered for this study. A total of 670 households were randomly drawn from the 8 villages and this formed the sample population. Data was collected using structured questionnaires and in depth interviews of key informants. Results: The findings indicated that the respondents were well informed on kala-azar; the cause and treatment. They also had favorable attitude towards the disease. They were aware that the disease was curable and sought treatment from health facilities as opposed to traditional alternatives. In seeking treatment, the residents were faced with challenges such as the long distance to the health facility, long period of treatment and the attendant cost of caring for a leishmaniasis patient. The respondents were aware that the disease was spread by an insect however, they were not aware of preventive measures. Most live in destitute houses which predisposed them to the infective bite of the vector. Most of the respondents are not employed and the cost of treatment, in addition to attendant costs places a heavy economic burden on them. Conclusion: The results showed good awareness of leishmaniasis, positive attitude and practices among the respondents which are important attributes in community participation. These findings are quite encouraging to researchers planning control programs because such a community would be more receptive to suggested control measures.

F1 Cross-Breed Between Susceptible BALB/c and Resistant Swiss mice Infected with Leishmania major Exhibit an Intermediate Phenotype for Lesion Sizes and Type 1 Cytokines but Show Low Level of Total IgG Antibodies

Our current understanding of the host immune response during leishmaniases largely derives from studies performed in mice due to the intrusive techniques required to study infected human patients. Swiss mice are highly resistant to Leishmania infections in concordance with observed response in humans, while BALB/c mice indicate a high‐susceptibility phenotype. Developing a cross‐breed between BALB/c and Swiss mice may have important consequences on disease development, immune responses and parasite killing, as yet, response of the cross‐breed to Leishmania infection is superficial. The aim of the present study was to determine disease course and immune responses in F1 cross‐breed between BALB/c and Swiss albino mice infected with L. major. Three mice groups were infected intradermally with stationary‐phase L. major parasites with parental strains (BALB/c and Swiss albino) as controls. Lesion development was monitored weekly for 8 weeks and monocyte chemotactic protein (MCP‐1), macrophage inflammatory protein (MIP‐1α), interferon‐gamma (IFN‐γ) and IgG antibody quantified by enzyme‐linked immunosorbent assay. The data were analysed using one‐way analysis of variance and Tukey–Kramer test. Results indicated F1 mice having intermediate lesion sizes, type 1 cytokine levels and footpad parasite loads as compared to the parental strains. However, the F1 mice had low levels of IgG antibodies and parasite burden in the spleen. (P < 0.05). This study concludes that the F1 cross‐breed between resistant and susceptible mice may be used as a requisite model to study the role of genetics in leishmaniases and perhaps other intracellular parasites.