Simon Karanja

Efficacy of the diamidine DB75 and its prodrug DB289, against murine models of human African trypanosomiasis.

The choice of drugs for the treatment of sleeping sickness is extremely limited. To redress this situation, the recently synthesised diamidine, 2,5-bis(4-amidinophenyl)-furan (DB75, furamidine) and its methamidoxime prodrug, 2,5-bis(4-amidinophenyl)-furan-bis-O-methylamidoxime (DB289, pafuramidine) were, together with pentamidine, evaluated for efficacy in acute rodent models. The activity was compared in three common mouse models that mimic the first stage of human African trypanosomiasis. The mice were infected with the pleomorphic T .b. rhodesiense strains KETRI2537 and STIB900 or with the monomorphic T. b. brucei strain STIB795. Importantly, DB75 showed activity superior to that of pentamidine at comparable doses in all three mouse models. Complete cures were achieved with oral dosing of the prodrug DB289 in all three models without any overt toxicity. This shows that the prodrug strategy was successful in terms of reducing toxicity and increasing efficacy and oral bioavailability.

Immunization coverage and its determinants among children aged 12 - 23 months in a peri-urban area of Kenya

Introduction The institutionalization of strong immunization services over recent years has ensured that today more than 70% of the worlds’ targeted population is reached. In Kenya, approximately 77% of children aged 12-23 months are fully vaccinated with some districts reporting even lower levels of coverage. However, low immunization coverage remains a challenge in low income and high population settings such as Kaptembwo Location, Nakuru district. Methods A cross sectional community based survey was undertaken between January and March 2011. Cluster sampling method was employed. Data was collected using pretested interviewer guided structured questionnaires through house to house visits. Data was analyzed in SPSS using descriptive, bivariate and multivariate logistic regression to identify independent predictors of full immunization. Results Complete immunization coverage was 76.6%. Coverage for specific antigens was; BCG (99.5%), OPV0 (97.6%), OPV 1(98.7%), OPV2 (96.6%), OPV3 (90.5%), Penta 1(98.9), Penta 2 (96.6%), Penta 3 (90.0%), Measles (77.4%). The drop-out rate between the first and third pentavalent vaccine coverage was 8.9%. Predictors of full immunization included number of children within the family, place of birth of the child, advice on date of next visit for growth monitoring and opinion on the health immunization services offered. Conclusion Complete immunization coverage among children aged 12-23 months is still below target. Efforts to improve vaccination coverage must take into account the immunization determinants found in this study. There is need to focus on strengthening of awareness strategies.

Immunospecific immunoglobulins and IL-10 as markers for Trypanosoma brucei rhodesiense late stage disease in experimentally infected vervet monkeys

Objective  To determine the usefulness of IL‐10 and immunoglobulin M (IgM) as biomarkers for staging HAT in vervet monkeys, a useful pathogenesis model for humans.

Prebiotic galacto-oligosaccharides mitigate the adverse effects of iron fortification on the gut microbiome: a randomised controlled study in Kenyan infants

Objective Iron-containing micronutrient powders (MNPs) reduce anaemia in African infants, but the current high iron dose (12.5 mg/day) may decrease gut Bifidobacteriaceae and Lactobacillaceae, and increase enteropathogens, diarrhoea and respiratory tract infections (RTIs). We evaluated the efficacy and safety of a new MNP formula with prebiotic galacto-oligosaccharides (GOS) combined with a low dose (5 mg/day) of highly bioavailable iron. Design In a 4-month, controlled, double-blind trial, we randomised Kenyan infants aged 6.5–9.5 months (n=155) to receive daily (1) a MNP without iron (control); (2) the identical MNP but with 5 mg iron (2.5 mg as sodium iron ethylenediaminetetraacetate and 2.5 mg as ferrous fumarate) (Fe group); or (3) the identical MNP as the Fe group but with 7.5 g GOS (FeGOS group). Results Anaemia decreased by ≈50% in the Fe and FeGOS groups (p<0.001). Compared with the control or FeGOS group, in the Fe group there were (1) lower abundances of Bifidobacterium and Lactobacillus and higher abundances of Clostridiales (p<0.01); (2) higher abundances of virulence and toxin genes (VTGs) of pathogens (p<0.01); (3) higher plasma intestinal fatty acid-binding protein (a biomarker of enterocyte damage) (p<0.05); and (4) a higher incidence of treated RTIs (p<0.05). In contrast, there were no significant differences in these variables comparing the control and FeGOS groups, with the exception that the abundance of VTGs of all pathogens was significantly lower in the FeGOS group compared with the control and Fe groups (p<0.01). Conclusion A MNP containing a low dose of highly bioavailable iron reduces anaemia, and the addition of GOS mitigates most of the adverse effects of iron on the gut microbiome and morbidity in African infants. Trial registration number NCT02118402.

The Effects on Tuberculosis Treatment Adherence from Utilising Community Health Workers: A Comparison of Selected Rural and Urban Settings in Kenya

Introduction Community Health Workers (CHWs) have been utilised for various primary health care activities in different settings especially in developing countries. Usually when utilised in well defined terms, they have a positive impact. To support Kenyas policy on engagement of CHWs for tuberculosis (TB) control, there is need to demonstrate effects of utilising them. Objectives This study assessed TB treatment adherence among patients who utilised CHWs in management of their illness in comparison to those who did not in urban and rural settings. Methods A retrospective cohort study was conducted in selected health facilities using standard clinical records for each TB patient registered for treatment between 2005 to 2011. Qualitative data was collected from CHWs and health care providers. Results The study assessed 2778 tuberculosis patients and among them 1499 (54%) utilized CHWs for their TB treatment. The urban setting in comparison with the rural setting contributed 70% of patients utilising the CHWs (p<0.001). Overall treatment adherence of the cohort was 79%. Categorizing by use of CHWs, adherence among patients who had utilized CHWs was 83% versus 68% among those that had not (p<0.001). In comparison between the rural and urban settings adherence was 76% and 81.5% (p<0.001) respectively and when categorized by use of CHWs it was 73% and 90% (p<0.001) for the rural and urban set ups respectively. Utilisation of CHWs remained significant in enhancing treatment adherence in the cohort with unadjusted and adjusted ORs; OR 2.25, (95% 1.86–2.73) p<0.001 and OR 1.98 (95% 1.51–2.5) p<0.001 respectively. It was most effective in the urban set-up, OR 2.65 (95% 2.02–3.48, p<0.001) in comparison to the rural set up, OR 0.74 (95% 0.56–0.97) p = 0.032. Conclusion Utilisation of CHWs enhanced TB treatment adherence and the best effects were in the urban set-up.

Questionnaire Survey on the Occurrence of Risk factors for Toxoplasma gondii infection amongst Farmers in Thika District, Kenya

A survey was conducted to determine the occurrence of risk factors for Toxoplasma gondii infection amongst farmers in Thika District, Kenya. Interviews were conducted in a total of 385 households using a structured questionnaire. The water consumed at household level originated from taps (74.3%), rivers or streams (15.1%), wells (5.4%) and boreholes (5.2%). A number of households (46.8%) consumed water without boiling or applying any form of treatment. All respondents washed vegetables before cooking, whilst 99.0% washed fruits before eating. Boiled milk was preferred by 99.5% of the farmers. The majority (85.2%) consumed beef more often, whilst 1.6% consumed pork. The majority (98.7%) consumed thoroughly cooked meat. Meat was preserved by 17% of farmers. Only four farmers (1.2%) who practised mixed farming used gloves when handling livestock manure. Five farmers (1.6%) reported the occurrence of abortion in ruminants and pigs on their farms within the last two years before the study. Almost half (44.9%) of the households owned cats, which were kept mainly as pets (79.8%) and for deterring rodents (20.2%). The majority of households (91.3%) fed the cats on leftovers, whilst 8.1% fed cats with raw offal. Sixteen households (9.2%) provided housing for cats. Only five households (2.8%) had litter boxes, but none of the households with litter boxes used gloves when cleaning them out. Disposal of cat faeces was done mainly by women (55.5%). Only one farmer (0.3%) had some knowledge about toxoplasmosis, but was not aware of the transmission mechanism. The study highlights the need for public health education to raise awareness of risk factors for toxoplasmosis.

IL-6 is Upregulated in Late-Stage Disease in Monkeys Experimentally Infected with Trypanosoma brucei rhodesiense

The management of human African trypanosomiasis (HAT) is constrained by lack of simple-to-use diagnostic, staging, and treatment tools. The search for novel biomarkers is, therefore, essential in the fight against HAT. The current study aimed at investigating the potential of IL-6 as an adjunct parameter for HAT stage determination in vervet monkey model. Four adult vervet monkeys (Chlorocebus aethiops) were experimentally infected with Trypanosoma brucei rhodesiense and treated subcuratively at 28 days after infection (dpi) to induce late stage disease. Three noninfected monkeys formed the control group. Cerebrospinal fluid (CSF) and blood samples were obtained at weekly intervals and assessed for various biological parameters. A typical HAT-like infection was observed. The late stage was characterized by significant (P < 0.05) elevation of CSF IL-6, white blood cell count, and total protein starting 35 dpi with peak levels of these parameters coinciding with relapse parasitaemia. Brain immunohistochemical staining revealed an increase in brain glial fibrillary acidic protein expression indicative of reactive astrogliosis in infected animals which were euthanized in late-stage disease. The elevation of IL-6 in CSF which accompanied other HAT biomarkers indicates onset of parasite neuroinvasion and show potential for use as an adjunct late-stage disease biomarker in the Rhodesian sleeping sickness.

Lipid metabolism and other metabolic changes in vervet monkeys experimentally infected with Trypanosoma brucei rhodesiense

Background  Human African trypanosomiasis is associated with metabolic changes which have not been well characterized.

Loop Mediated Isothermal Amplification for Detection of Trypanosoma brucei gambiense in Urine and Saliva Samples in Nonhuman Primate Model.

Human African trypanosomiasis (HAT) is a vector-borne parasitic zoonotic disease. The disease caused by Trypanosoma brucei gambiense is the most prevalent in Africa. Early diagnosis is hampered by lack of sensitive diagnostic techniques. This study explored the potential of loop mediated isothermal amplification (LAMP) and polymerase chain reaction (PCR) in the detection of T. b. gambiense infection in a vervet monkey HAT model. Six vervet monkeys were experimentally infected with T. b. gambiense IL3253 and monitored for 180 days after infection. Parasitaemia was scored daily. Blood, cerebrospinal fluid (CSF), saliva, and urine samples were collected weekly. PCR and LAMP were performed on serum, CSF, saliva, and urine samples. The detection by LAMP was significantly higher than that of parasitological methods and PCR in all the samples. The performance of LAMP varied between the samples and was better in serum followed by saliva and then urine samples. In the saliva samples, LAMP had 100% detection between 21 and 77 dpi, whereas in urine the detection it was slightly lower, but there was over 80% detection between 28 and 91 dpi. However, LAMP could not detect trypanosomes in either saliva or urine after 140 and 126 dpi, respectively. The findings of this study emphasize the importance of LAMP in diagnosis of HAT using saliva and urine samples.

Consumption of galacto-oligosaccharides increases iron absorption from a micronutrient powder containing ferrous fumarate and sodium iron EDTA: a stable-isotope study in Kenyan infants

Background: Whether consumption of prebiotics increases iron absorption in infants is unclear.Objective: We set out to determine whether prebiotic consumption affects iron absorption from a micronutrient powder (MNP) containing a mixture of ferrous fumarate and sodium iron EDTA (FeFum+NaFeEDTA) in Kenyan infants.Design: Infants (n = 50; aged 6-14 mo) consumed maize porridge that was fortified with an MNP containing FeFum+NaFeEDTA and 7.5 g galacto-oligosaccharides (GOSs) (Fe+GOS group, n = 22) or the same MNP without GOSs (Fe group, n = 28) each day for 3 wk. Then, on 2 consecutive days, we fed all infants isotopically labeled maize porridge and MNP test meals containing 5 mg Fe as 57FeFum+Na58FeEDTA or ferrous sulfate (54FeSO4). Iron absorption was measured as the erythrocyte incorporation of stable isotopes. Iron markers, fecal pH, and bacterial groups were assessed at baseline and 3 wk. Comparisons within and between groups were done with the use of mixed-effects models.Results: There was a significant group-by-compound interaction on iron absorption (P = 0.011). The median percentages of fractional iron absorption from FeFum+NaFeEDTA and from FeSO4 in the Fe group were 11.6% (IQR: 6.9-19.9%) and 20.3% (IQR: 14.2-25.7%), respectively, (P < 0.001) and, in the Fe+GOS group, were 18.8% (IQR: 8.3-37.5%) and 25.5% (IQR: 15.1-37.8%), respectively (P = 0.124). Between groups, iron absorption was greater from the FeFum+NaFeEDTA (P = 0.047) in the Fe+GOS group but not from the FeSO4 (P = 0.653). The relative iron bioavailability from FeFum+NaFeEDTA compared with FeSO4 was higher in the Fe+GOS group than in the Fe group (88% compared with 63%; P = 0.006). There was a significant time-by-group interaction on Bifidobacterium spp. (P = 0.008) and Lactobacillus/Pediococcus/Leuconostoc spp. (P = 0.018); Lactobacillus/Pediococcus/Leuconostoc spp. decreased in the Fe group (P = 0.013), and there was a nonsignificant trend toward higher Bifidobacterium spp. in the Fe+GOS group (P = 0.099). At 3 wk, iron absorption was negatively correlated with fecal pH (P < 0.001) and positively correlated with Lactobacillus/Pediococcus/Leuconostoc spp. (P = 0.001).Conclusion: GOS consumption by infants increased iron absorption by 62% from an MNP containing FeFum+NaFeEDTA, thereby possibly reflecting greater colonic iron absorption. This trial was registered at clinicaltrials.gov as NCT02666417.