Background. Emergence of Plasmodium resistance to antimalarial drugs presents a major drawback in efforts to control malaria. To address this problem, there is an urgent and continuous need for the ...development of new and effective antimalarial agents. Senna occidentalis (L.) link extract has exhibited in vitro antiplasmodial activity in many pharmacological studies. To our knowledge, data on its in vivo antimalarial efficacy is still very limited. A recent study demonstrated that polar extracts from the plant roots inhibit Plasmodium berghei proliferation in a mouse model. This study further describes the efficacy and safety of a methanolic root extract of the plant as an antimalarial agent by demonstrating its effect on hematological, biochemical, and histological parameters of Plasmodium berghei-infected BALB/c mice. Methods. Rane’s test, a curative approach, was used to evaluate the antimalarial efficacy of Senna occidentalis methanolic root extract in Plasmodium berghei-infected BALB/c mice. The effect of the extract on both hematological and biochemical parameters was evaluated using automated analyzers. Kidney, liver, lung, spleen, and brain tissues were harvested from euthanized mice and examined for changes in organ architecture. Results. This study demonstrates that methanolic root extract of Senna occidentalis significantly inhibited Plasmodium berghei parasitemia in BALB/c mice (p<0.01). Infected mice that were treated with the extract depicted a significantly low level of total leucocytes (p<0.01), red blood cell distribution width (p<0.01), and a significantly high hemoglobin concentration (p<0.001) compared to the infected animals that were administered with the vehicle only. The infected animals that were treated with the extract exhibited a significantly low level of urea, creatinine, bilirubin, and alkaline phosphatase (p<0.05), compared to the infected animals that were given the vehicle only. The level of sodium, potassium and chloride ions, lymphocytes, granulocytes, hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration, total protein, albumin, aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), total platelets, mean platelet volume (MPV), and platelet distribution width of the infected animals treated with the extract was not significantly different from those of the infected animals that were given the vehicle only (p>0.05). The extract alleviated organ pathological changes in the infected mice. The extract did not induce any remarkable adverse effect on the growth, hematological, and biochemical parameters of uninfected animals (p>0.05). In addition, administration of the extract did not alter the gross appearance and histological architecture of the organs, implying that the extract was well tolerated in mice. Conclusions. Senna occidentalis methanolic root extract exhibited good antimalarial activity against Plasmodium berghei and may be safe in mice.
Antivenom is the treatment of choice for snakebite, which annually kills an estimated 32,000 people in sub-Saharan Africa and leaves approximately 100,000 survivors with permanent physical ...disabilities that exert a considerable socioeconomic burden. Over the past two decades, the high costs of the most polyspecifically-effective antivenoms have sequentially reduced demand, commercial manufacturing incentives and production volumes that have combined to create a continent-wide vacuum of effective snakebite therapy. This was quickly filled with new, less expensive antivenoms, many of which are of untested efficacy. Some of these successfully marketed antivenoms for Africa are inappropriately manufactured with venoms from non-African snakes and are dangerously ineffective. The uncertain efficacy of available antivenoms exacerbates the complexity of designing intervention measures to reduce the burden of snakebite in sub-Saharan Africa. The objective of this study was to preclinically determine the ability of antivenoms available in Kenya to neutralise the lethal effects of venoms from the most medically important snakes in East Africa.
We collected venom samples from the most medically important snakes in East Africa and determined their toxicity in a mouse model. Using a 'gold standard' comparison protocol, we preclinically tested the comparative venom-neutralising efficacy of four antivenoms available in Kenya with two antivenoms of clinically-proven efficacy. To explain the variant efficacies of these antivenoms we tested the IgG-venom binding characteristics of each antivenom using in vitro IgG titre, avidity and venom-protein specificity assays. We also measured the IgG concentration of each antivenom.
None of the six antivenoms are preclinically effective, at the doses tested, against all of the most medically important snakes of the region. The very limited snake polyspecific efficacy of two locally available antivenoms is of concern. In vitro assays of the abilities of 'test' antivenom IgGs to bind venom proteins were not substantially different from that of the 'gold standard' antivenoms. The least effective antivenoms had the lowest IgG content/vial.
Manufacture-stated preclinical efficacy statements guide decision making by physicians and antivenom purchasers in sub-Saharan Africa. This is because of the lack of both clinical data on the efficacy of most of the many antivenoms used to treat patients and independent preclinical assessment. Our preclinical efficacy assessment of antivenoms available in Kenya identifies important limitations for two of the most commonly-used antivenoms, and that no antivenom is preclinically effective against all the regionally important snakes. The potential implication to snakebite treatment is of serious concern in Kenya and elsewhere in sub-Saharan Africa, and underscores the dilemma physicians face, the need for clinical data on antivenom efficacy and the medical and societal value of establishing independent preclinical antivenom-efficacy testing facilities throughout the continent.
Senna occidentalis (L.) Link has been used worldwide in traditional treatment of many diseases and conditions including snakebite. In Kenya, a decoction from the plant roots taken orally, is used as ...a cure for malaria. Several studies have demonstrated that extracts from the plant possess antiplasmodial activity, in vitro. However, the safety and curative potency of the plant root against established malaria infection is yet to be scientifically validated, in vivo. On the other hand, there are reports on variation in bioactivity of extracts obtained from this plant species, depending on the plant part used and place of origin among other factors. In this study, we demonstrated the antiplasmodial activity of Senna occidentalis roots extract in vitro, and in mice.
Methanol, ethyl acetate, chloroform, hexane and water extracts of S. occidentalis root were tested for in vitro antiplasmodial activity against Plasmodium falciparum, strain 3D7. Cytotoxicity of the most active solvent extracts was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the curative potency in Plasmodium berghei infected mice evaluated by Rane's test.
All of the solvent extracts tested in this study inhibited the propagation of P. falciparum, strain 3D7, in vitro, with polar extracts being more active than non-polar ones. Methanolic extracts had the highest activity (IC
= 1.76) while hexane extract displayed the lowest activity (IC
= 18.47). At the tested concentrations, methanolic and aqueous extracts exhibited high selectivity index against P. falciparum strain 3D7 (SI > 10) in the cytotoxicity assay. Further, the extracts significantly suppressed the propagation of P. berghei parasites (P < 0.05) in vivo and increased the survival time of the infected mice (P < 0.0001).
Senna occidentalis (L.) Link root extract inhibits the propagation of malaria parasites in vitro and in BALB/c mice.
Tunga penetrans are fleas that cause tungiasis, a condition characterized by high transmission rate due to poor housing conditions, social neglect and inadequate health care in economically ...disadvantaged communities in developing countries. This study therefore aimed at characterizing jiggers antigens to identify immunodominant ones to help understand immunological behavior of the parasite that would otherwise be important in future control of the parasite. Samples were gravid fleas and blood samples from infested individuals in Kahuro and Murang'a East district in Murang'a County. Freeze and thaw was used to extract soluble proteins from the fleas. Ouchterlony Double immunodiffusion was used to assess antigen-antibody reactions between extracted soluble protein and the serum from immunized rats, Rattus norvegicus prior to analysis of human sera. These results were comparable to results of immunoelectrphoresis. Jigger protein isolates were analyzed in Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis technique (SDS-PAGE), against Pharmacia standard protein markers. Further analysis of jigger antigens against pooled human sera from infested victims in Western blot revealed three immunodominant antigens. Using simple regression analysis molecular weights of the three immunodominant antigens were estimated as 51.795, 23.395 and 15.38 kDa respectively. These results are important since they would help understand immunological behavior of the parasites. This would help to create basis for designing and improving approaches against jiggers such as development of immune prophylaxis to complement social science approaches that is mainly concerned with maintenance of high standards of hygiene.
Infections from extended spectrum beta lactamases (ESBLs) producing enterobacteriaceae are increasingly being reported in the community setting. These infections are often multidrug resistant, with ...clinical and epidemiological implications, and necessitate surveillance measures based on local data. In the present study ESBLs genotypes were correlated with susceptibility to cephalosporins among ESBL-producing Escherichia coli and Klebsiella pneumoniae isolates acquired in the community.
We investigated 28 E. coli and 24 K. pneumoniae isolates by PCR for the presence of blaSHV, blaCTX-M, and blaTEM. Minimum inhibitory concentration (MIC) for cephalosporins was determined by use of E-tests.
blaCTX-M was detected in 46 (88.5%), blaSHV in 13 (25%) and blaTEM in18 (34.6%) of the isolates. Nineteen (36.5%) isolates had more than one genotype detected. Urine specimens provided most of the ESBL-producing isolates (71%) followed by respiratory specimens (11%). MIC50 for cefotaxime, ceftazidime, and ceftriaxone were at 60 µg/ml, 13 µg/ml, and 139 µg/ml, respectively. There was a statistically significant association (p-value = 0.017) between blaSHV and resistance to ceftazidime. Though other associations could be seen among the genotypes and susceptibility profiles of the three drugs, they were not statistically significant. Twenty-four (52.2%) of the blaCTX-M isolates were sensitive and nine (19.6%) resistant to ceftazidime. For cefotaxime, 29 (63%) of blaCTX-M isolates were resistant and two (4.3%) were sensitive.
The predominant ESBL genotype in the local community-acquired infections is blaCTX-M , most of which involved the urinary tract. ESBL genes elevated MICs for the cephalosporins, but only blaSHV could predict resistance to ceftazidime.
Placental malaria (PM) causes adverse pregnancy outcomes in the mother and her foetus. It is difficult to study PM directly in humans due to ethical challenges. This study set out to bridge this gap ...by determining the outcome of PM in non-immune baboons in order to develop a non-human primate model for the disease.
Ten pregnant baboons were acquired late in their third trimester (day 150) and randomly grouped as seven infected and three non-infected. Another group of four nulligravidae (non-pregnant) infected was also included in the analysis of clinical outcome. Malaria infection was intravenously initiated by Plasmodium knowlesi blood-stage parasites through the femoral vein on 160(th) day of gestation (for pregnant baboons). Peripheral smear, placental smear, haematological samples, and histological samples were collected during the study period. Median values of clinical and haematological changes were analysed using Kruskal-Wallis and Dunn's Multiple Comparison Test. Parasitaemia profiles were analysed using Mann Whitney U test. A Spearman's rank correlation was run to determine the relationship between the different variables of severity scores. Probability values of P <0.05 were considered significant.
Levels of white blood cells increased significantly in pregnant infected (34%) than in nulligravidae infected baboons (8%). Placental parasitaemia levels was on average 19-fold higher than peripheral parasitaemia in the same animal. Infiltration of parasitized erythrocytes and inflammatory cells were also observed in baboon placenta. Malaria parasite score increased with increase in total placental damage score (rs = 0.7650, P <0.05) and inflammatory score (rs = 0.8590, P <0.05). Although the sample size was small, absence of parasitized erythrocytes in cord blood and foetal placental region suggested lack of congenital malaria in non-immune baboons.
This study has demonstrated accumulation of parasitized red blood cells and infiltration of inflammatory cells in the placental intravillous space (IVS) of baboons that are non-immune to malaria. This is a key feature of placental falciparum malaria in humans. This presents the baboon as a new model for the characterization of malaria during pregnancy.
Tungiasis is a parasitic skin disease brought about by female
when they burrow into the skin of their hosts. It is a disease that has largely been ignored. Epidemiology of tungiasis has not been ...widely studied in Kenya which could negatively affect effective intervention strategies. This study therefore sought to investigate epidemiology of tungiasis in selected areas in Kiharu constituency, Murang'a County in Kenya.
The study population comprised of public primary school pupils, the most vulnerable age group (
= 508) in Gaturi, Kimathi, Kahuhia and Mugoiri in Kiharu constituency. Public primary school pupils in the study area were randomly sampled. Through questionnaires and observations, data was collected.
The overall prevalence of tungiasis in pupils in the study area was 19.1 %. In multinomial logistic regression analysis some factors were identified to be associated with tungiasis such as lack of regular use of closed foot ware (Adjusted odds ratio = 10.45; 95 % Confidence Interval; 1.49-73.23), living in earthen mud walled houses (aOR = 13.78; 95 % CI = 3.127-60.69), sharing living quarters with domestic animals (aOR = 3.1; 95 % CI = 0.003-.046) and learning in classrooms with dusty floors (aOR = 14.657; 95 % CI = 2.262-94.95). Treatment of tungiasis was found to be mainly through mechanical removal of embedded
.
This study shows that tungiasis in the selected study areas of Kiharu constituency is a disease of significant health concern. Factors associated with tungiasis were identified that should be the focus of sustainable and effective control measures.
Efforts in search of lasting malaria vaccine have led to the development of transgenic rodent malaria parasites. As a result, wild type
ANKA (WTPbA) has recently been transformed to express mouse ...interferon gamma (mIFN-γ). The immunomodulatory effect of this transgenic parasite on WTPbA infection has been demonstrated. However, the protective immune responses after repeated immunization with soluble lysate of this parasite has not been investigated.
Soluble lysate of transgenic PbA (TPbA) was prepared and concentration of IFN-γ in lysate determined by ELISA. Four groups of 20 BALB/c mice each (two treatment groups and two control groups) were setup. Treatment Groups 1 and 2 were primed (at day 0) with lysate of TPbA containing 75 pg/ml IFN-γ and live TPbA parasites respectively. Infection in Group 2 mice was cured with Coartem™ at 450 mg/kg for 3 days. At day 14 post-priming, both groups were boosted twice at day 14 and day 28 with lysate of TPbA containing 75 pg/ml IFN-γ and 35 pg/ml IFN-γ respectively. Blood and spleen samples were collected at day 0, day 14, day 21 and day 28 for preparation of serum and cell cultures respectively. Serum IgG and cytokines (TNF-α and IFN-γ) levels in culture supernatant were measred by ELISA.Survivorship and parasitemia were daily monitored for 21 days. Data were statistically analyzed using ANOVA student's
test. A
value of <0.05 was considered significant.
At day 28 post-priming, IFN-γ production in Group 1 was tenfold higher than in RBC control group (
= 0.070) There was significant difference in IFN-γ production among the groups at day 28 (
< 0.0001). TNF-α production in Group 1 mice increased fourfold in Group 2 mice from day 14 to day 28 post-immunization (
= 0.0005). There was no significant effect on serum IgG production. Mice in treatment groups survived 5 to 4 days longer compared to non-immunized group.
The study has demonstrated that, repeated immunization with soluble lysate of TPbA induces Th 1 response leading to increased IFN-γ and TNF-γ production.
PDF
