Trypanosoma brucei gambiense infection in vervet monkeys: a potential model for early-stage disease.

BACKGROUND: Non-human primates are important experimental models for human African trypanosomiasis. METHODS: Six monkeys were intravenously inoculated with 10(5) trypanosomes of Trypanosoma brucei gambiense IL 3253. They were monitored for 180 days for parasitemia, hematology, clinical and biochemical profiles. RESULTS: The pre-patent period was 2-3 days. From 33 to 123 dpi, the parasitemia was low and only detectable by the hematocrit centrifugation technique. Thereafter, to the end of the experimental period, the parasitemia was undetectable by parasitological methods. Clinical signs observed were lymphadenopathy and splenomegaly. Hematological changes included a decline in hemoglobin occurring between 14 and 56 dpi and a significant decline in platelet counts after infection. The levels of total protein, albumin and globulins increased from 26 dpi for the rest of the experimental period. No parasites were detected in cerebrospinal spinal fluid, and no brain pathology was observed. CONCLUSION: This vervet monkey model can only be used for early-stage disease Gambian sleeping sickness.

FACTORS INFLUENCING ADHERENCE TO ARVS AMONG PATIENTS ATTENDING COMPREHENSIVE CARE CLINIC WITHIN JOMO KENYATTA UNIVERSITY OF AGRICULTURE AND TECHNOLOGY, KIAMBU COUNTY, KENYA.

BACKGROUND: The efficacy of anti-retroviral Therapy (ART) depends on adherence to the prescribed regimen. However, lack of adherence leads to treatment failure and drug resistance among other negative outcomes. OBJECTIVE: To determine factors influencing adherence to ARVS among patients attending the Comprehensive Care Clinic (CCC) within Jomo Kenyatta University of Agriculture and Technology (JKUAT). DESIGN: A descriptive cross sectional study. SETTING: Comprehensive Care Clinic within JKUAT. SUBJECTS: Three hundred HIV positive patients, undergoing ART treatment and follow up at the JKUAT clinic for a minimum duration of one month before the study, were recruited. RESULTS: Of the 300 patients enrolled for the study (70% females and 30% males), 81% were adhering to ARV treatment. The factors that were significantly associated with adherence included; Support (encouragement and reminder to take drugs) (P = 0.025); the number of meals respondents took in a day (P = 0.001); pill burden (P = 0.002) and forgetfulness (P = 0.001). However, there was no significant relationship between adherence and age, marital status, education, employment status or time taken to travel to the clinic. CONCLUSION: This study concluded that, the observed level of sub-optimal adherence to ART (19%) is of public health concern. These patients are vulnerable to treatment failure and development of resistant viral strains. Consequently the modifiable factors (Support, Number of meals taken, pill burden, and forgetfulness, should be addressed to change the current tread.

IMMUNOLOGICAL PROFILES IN HIV POSITIVE PATIENTS FOLLOWING HAART INITIATION IN KIGALI, RWANDA.

BACKGROUND: Interleukin-10, IL-2 and IFN-γ are some of the crucial cytokines associated with HIV infection and pathogenesis. While IL-2 and IFN-γ play critical roles in host resistance to infection, IL-10 inhibits the synthesis IFN-γ, IL-2 at mRNA and protein level; exacerbating damage to immune system. OBJECTIVE: To determine the levels of, changes in and correlation between CD4 count, viral load, IL-10, IL-2 and IFN-γ before HAART and at six months of HAART among HIV positive patients in Kigali; with a view to understand cytokine networks particularly in relation to HAART; and to see whether they can be used as alternative markers of the disease progression. DESIGN: Longitudinal study. SETTING: Kagugu, Kimironko, Biryogo, Gitega Health Centres and Centre Medico-Social Cornum; all located in Kigali. SUBJECTS: Thirty three (33) HAART initiation eligible HIV positive patients including 13 women and 20 men. RESULTS: A drop in viral load (though only a small number of patients achieved an undetectable viraemia); a recovery of CD4+ cells, a decrease in IL-10 (though it remained high for many patients especially those with unchanged viraemia); and an increase in IL-2 and IFN-γ indicated a successful HAART. A negative correlation between CD4 count and viral load and between CD4 count and IL-10 (but r < -0.5) was observed. IL-10 correlated positively and strongly with viremia (r > 0.5 at both time points: p-values < 0.05). There was no significant correlation between CD4 count, IL-2 and IFN-y. CONCLUSION: Results demonstrated the down-regulatory effect of IL-10 on Th1 cytokines and that a shift from Th1 to Th2 cytokine is associated with HIV disease progression. A successful HAART results in CD4+ cells recovery, drop in viraemia and IL-10 with up-regulation of Th1 cytokines. Also, findings show potential usefulness of IL-10 as a marker of HIV disease progression.

Immunological Profiles in HIV Positive Patients Following HAART Initiation in Kigali; Rwanda

Background: Interleukin-10; IL-2 and IFN -? are some of the crucial cytokines associated with HIV infection and pathogenesis. While IL-2 and IFN-? play critical roles in host resistance to infection; IL-10 inhibits the synthesis IFN-?; IL-2 at mRNA and protein level; exacerbating damage to immune system. Objective: To determine the levels of; changes in and correlation between CD4 count; viral load; IL-10; IL-2 and IFN-? before HAART and at six months of HAART among HIV positive patients in Kigali; with a view to understand cytokine networks particularly in relation to HAART ; and to see whether they can be used as alternative markers of the disease progression. Design: Longitudinal study. Setting: Kagugu; Kimironko; Biryogo; Gitega Health Centres and Centre Medico-Social Cornum; all located in Kigali. Subjects: Thirty three (33) HAART initiation eligible HIV positive patients including 13 women and 20 men. Results: A drop in viral load (though only a small number of patients achieved an undetectable viraemia); a recovery of CD4+ cells; a decrease in IL-10 (though it remained high for many patients especially those with unchanged viraemia); and an increase in IL-2 and IFN-? indicated a successful HAART . A negative correlation between CD4 count and viral load and between CD4 count and IL-10 (but r -0.5) was observed. IL-10 correlated positively and strongly with viremia (r 0.5 at both time points: p-values 0.05). There was no significant correlation between CD4 count; IL-2 and IFN-?. Conclusion: Results demonstrated the down-regulatory effect of IL-10 on Th1 cytokines and that a shift from Th1 to Th2 cytokine is associated with HIV disease progression. A successful HAART results in CD4+ cells recovery; drop in viraemia and IL-10 with up-regulation of Th1 cytokines. Also; findings show potential usefulness of IL-10 as a marker of HIV disease progression

Preclinical drug evaluation system in the Plasmodium knowlesi baboon model of malaria: the methotrexate study.

BACKGROUND: Drug resistance against first-line antimalarials warrants search for new lead compounds and repurposing of drugs such as methotrexate. Animal models are required for preclinical drug development before clinical testing. This study aimed to develop a preclinical drug development system in baboons infected with Plasmodium knowlesi. METHODS: Protocols for drug administration, pharmacokinetics, clinical chemistry and haematology were developed in the baboon model. Baboons were infected with P. knowlesi and methotrexate administered orally for 5 days. Clinical signs, parasitaemia, gross and histopathology examinations were conducted to determine effect of methotrexate in baboons. RESULTS: No major clinical chemistry, haematology and pathological changes attributable to methotrexate were observed. Parasitaemia suppression of 77.67% was achieved at a methotrexate dose of 3.0 mg/kg. CONCLUSIONS: A protocol for preclinical drug development in the baboon was optimized. Methotrexate suppressed P. knowlesi malaria in baboons. These findings warrant further characterization of methotrexate for use in combination therapy.

PREVALENCE AND INTENSITY OF SINGLE AND MIXED SCHISTOSOMA MANSONI AND SCHISTOSOMA HAEMATOBIUM INFECTIONS IN PRIMARY SCHOOL CHILDREN IN RACHUONYO NORTH DISTRICT, HOMABAY COUNTY, WESTERN KENYA.

OBJECTIVE: To determine the prevalence andintensity of single and mixed schistosomiasis infection among primary school children in Rachuonyo North District, Homabay County in western Kenya. DESIGN: A descriptive cross sectional study. SETTING: A parasitological survey involving six primary schools in Rachuonyo North District, Homabay County. SUBJECTS: Four hundred and seventy four(474) school children, seven to 15 years old. Each child provided a urine and stool sample for diagnosis of schistosome and soil-transmitted helminth infections. Urine samples were processed using the filtration technique and the sample examined by microscopy for Schistosoma haematobium ova. Stool samples were processed by the Kato-Katz technique and the sample examined by microscopy for ova of S. mansoni and soil-transmitted helminths. RESULTS: Prevelance of S.haematobium was 37.6%, S.mansoni (12.2%), hookworm (14.6%), Ascaris lumbricoides (6.3%), Trichuris trichiura (5.3%) among the children in the participating schools. Overall, 78.6% of the children infected with S.haematobium had light infection (<50 eggs per 10 ml of urine) and the rest (21.4%) had heavy infection (50 eggs per 10 ml of urine). On the hand, 75.9% of those with S.mansoni had light infection (one to 99 eggs per gram of stool (EPG), and the rest (24.1%) had moderate infection intensities (100-399 (EPG). CONCLUSION: This is the first report in which both S.haematobium and S.mansoni are found together in the same geographic locality in high prevalence in the Lake Victoria region of western Kenya, with S. haematobium being the most predominant in some places. Rachuonyo North District becomes a new focus of mixed human schistosome infections in Kenya. The significant burden of schistosomiasis in this area highlights the need to include regular treatment for schistosomiasis in the national school based deworming programme especially now that the infection occurs in areas more than five kilometres away from the lake.

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. METHODS: Chlorocebus aethiops were experimentally infected with Trypanosoma brucei rhodesiense and late-stage disease induced at 28 days post-infection. Ear prick blood for glucose determination and blood samples were obtained at weekly intervals for 56 days. Analysis was carried out using dry chemistry analysis. RESULTS: In early infection, there was a significant increase in creatine kinase, while during early and transitional stage of infection there was a significant decrease in glucose and high-density lipoprotein and an increase in triglyceride levels. In the late stage, there was a significant increase in both total cholesterol and LDL levels. CONCLUSIONS: Further investigations should focus on levels of total cholesterol during the follow-up period in curatively treated vervet monkeys. Apart from their importance in disease staging, the changes in lipids levels may also affect the pharmacokinetics of some trypanocides.

Prevalence and types of coinfections in sleeping sickness patients in kenya (2000/2009).

The occurrence of coinfections in human African trypanosomiasis (HAT) patients was investigated using a retrospective data of hospital records at the National Sleeping Sickness Referral Hospital in Alupe, Kenya. A total of 31 patients, 19 males and 12 females, were diagnosed with HAT between the years 2000 and 2009. The observed co-infections included malaria (100%), helminthosis (64.5%), typhoid (22.5%), urinary tract infections (16.1%), HIV (12.9%), and tuberculosis (3.2%). The species of helminthes observed included Ancylostoma duodenale (38.7%), Ascaris lumbricoides (45.7%), Strongyloides stercoralis (9.7%), and Taenia spp. (3.2%). The patients were also infected with Entamoeba spp. (32.3%) and Trichomonas hominis (22.6%) protozoan parasites. The main clinical signs observed at the point of admission included headache (74.2%), fever (48.4%), sleep disorders (45.2%), and general body pain (41.9%). The HAT patients were treated with suramin (early stage, 9/31) and melarsoprol (late stage, 22/31). In conclusion, the study has shown that HAT patients have multiple co-infections which may influence the disease pathogenesis and complicate management of HAT.

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. METHODS: Vervet monkeys were infected with Trypanosoma brucei rhodesiense and subsequently given sub-curative and curative treatment 28 and 140 days post-infection (dpi) respectively. Matched serum and CSF samples were obtained at regular intervals and immunospecific IgM, immunoglobulin G (IgG) and IL-10 were quantified by ELISA. RESULTS: There was no detectable immunospecific IgM and IgG in the CSF before 49 dpi. CSF IgM and IgG and serum IgM were significantly elevated with peak levels coinciding with meningoencephalitis 98 dpi. The serum IL-10 was upregulated in both early and late disease stage, coinciding with primary and relapse parasitaemia respectively. CSF white cell counts (CSF WCC) were elevated progressively till curative treatment was given. After curative treatment, there was rapid and significant drop in serum IgM and IL-10 concentration as well as CSF WCC. However, the CSF IgM and IgG remained detectable to the end of the study. CONCLUSIONS: Serum and CSF concentrations of immunospecific IgM and CSF IgG changes followed a pattern that mimics the progression of the disease and may present reliable and useful biomarkers of the disease stage. Due to rapid decline, serum IgM and IL-10 are, additionally, potential biomarkers of the success of chemotherapy.

Biochemical changes in cerebrospinal fluid of Chlorocebus aethiops naturally infected with zoonotic Meningonema peruzzii.

BACKGROUND: Thirty-four wild Chlorocebus aethiops monkeys were trapped for research purposes. METHODS: During routine quarantine check-up, cerebrospinal fluid (CSF) and blood were microscopically examined for parasites. Estimations of CSF protein levels were made by the biuret method and the white cell counts by the hemocytometer. RESULTS: Seven monkeys demonstrated microfilariae in blood and CSF. This was accompanied by a two- and ninefold increase in CSF total protein and white cell counts, respectively. Necropsy of one of the blood and CSF microfilariae-positive animals revealed the presence of adult worms in the brain meninges. The parasites were identified as the zoonotic filaroid nematode Meningonema peruzii. CONCLUSIONS: Wild C. aethiops monkeys developed CSF changes resulting, most probably, from infection with M. peruzii. Moreover, the monkeys could be acting as an important reservoir. The study highlights the need for epidemiological and pathogenological studies of this parasite, which is of public health significance. Moreover, C. aethiops proved to be a useful primate model for the study of this zoonotic infection.

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.

Evaluation of a preliminary title to protect zero-grazed dairy cattle with insecticide-treated mosquito netting in western Kenya.

The incidence of trypanosome infection was monitored in dairy cattle during a 6-month trial in Busia and Teso districts, western Kenya, to assess the efficacy of insecticide-treated netting for protection against tsetse flies. Frequently, the fragile netting did not last longer than 2 months because of destruction by strong wind or animal movements. Also, many farmers let their cattle graze freely outside the units during the day, despite technical advice, resulting in exposure of the free-ranging animals to habitats suitable for tsetse and thereby an increased risk of trypanosome infections. The trial groups thus comprised 34 animals from 11 dairy units that were continuously protected, and 153 animals from 46 dairy units that were partially protected. The control group consisted of 162 animals in 42 unprotected units. The phase-contrast buffy-coat technique was used for parasitological monitoring. The mean hazard rate for trypanosomes was significantly lower in protected cows, with a value of 0.007 as opposed to 0.02 for the control animals. Mean packed cell volumes (PCV) were significantly higher in protected cattle (29.7%) than in unprotected ones (27.6%). Farmers with protected animals also reported fewer nuisance flies and mosquitoes in their compounds.

Evaluation of antigen and antibody rapid detection tests for Trypanosoma evansi infection in camels in Kenya.

The card agglutination test for Trypanosoma evansi (CATT/T. evansi) for the detection of antibodies, and Suratex for the detection of circulating antigens were compared in a cross-sectional study involving camels in eastern and central parts of Kenya. Of the 2227 camels screened, 2038 were owned by nomadic pastoralists in T. evansi endemic areas in eastern Kenya. A herd of 86 camels were from a ranch in Mugwoni. In Athi River area, 35 camels belonged to Kenya Trypanosomiasis Research Institute, and 68 were slaughter animals. Diagnostic sensitivity estimates were obtained by testing sera from 51 camels that had been found to be parasitologically positive by the haematocrit centrifugation technique, buffy-coat technique and mouse inoculation. Diagnostic specificity was estimated by testing sera from 35 camels known to be trypanosome-free. Positive and negative predictive values (NPVs) were calculated using a range of prevalence values. The sensitivity of CATT/T. evansi (68.6%) was higher than that of Suratex (58.8%), but not significantly. Both tests had equally high specificity (100%). The overall prevalence was 2.3% (51 out of 2227) by parasite detection, 32.2% (327 out of 1017) by CATT/T. evansi and 19.6% (188 out of 961) by Suratex. Overall, there was a positive association between CATT/T. evansi and Suratex though the strength of association was low (McNemar's test=46.12, P=0.001; kappa=0.26, CI: 0.20-0.33). Parasite prevalence ranged from 0% in several herds to 27.8% in a herd in Isiolo. Prevalence was highest in Isiolo with 2.5% (51 out of 2030) by parasitological detection, 38.8% (321 out of 828) by CATT/T. evansi and 21.9% (169 out of 772) by Suratex. In Mugwoni prevalence was 7 and 18% by CATT/T. evansi and Suratex, respectively, and no parasites were detected. In Athi River Suratex detected 2.9% (3 out of 103) positive while CATT/T. evansi and parasitological methods gave negative results. At prevalence values between 10 and 100%, CATT/T. evansi as well as Suratex had infinitely high positive predictive values, whereas Suratex had a lower NPV than CATT/T. evansi. In conclusion, results of this study showed that CATT/T. evansi and Suratex were able to detect aparasitaemic infections rapidly and were more sensitive than parasitological methods in revealing the true extent of trypanosomosis in a herd. The tests effectively complemented parasitological methods in the detection of T. evansi infections in camels.

Animal-level risk factors for Trypanosoma evansi infection in camels in eastern and central parts of Kenya.

Point prevalences and animal-level risk factors for Trypanosoma evansi infection were investigated in a cross-sectional study that involved 2227 camels from eastern and central parts of Kenya. The screening tests used were haematocrit centrifugation technique (HCT), mouse inoculation and latex agglutination (Suratex). All camels were screened with HCT, while 396 and 961 of them were, in addition, screened with mouse inoculation and Suratex tests, respectively. Parasitological and Suratex test results were used in parallel to determine the number of camels exposed to T. evansi infections. Statistical analyses were conducted using Statistical Analysis Systems. Parasitological and Suratex test results in parallel were dependent variables in multivariable logistic regression models that determined risk factors for T. evansi infection. Herd-level clustering was corrected with general estimation equations. The prevalences were 2.3% and 19.6%, using parasitological and Suratex tests, respectively, and 21.7% when both tests were used in parallel. There was a positive association between the screening tests (McNemar's test = 104.8, P = 0.001) although the strength of association was low (Kappa = 0.2; 95% CI: 0.1-0.3). Before accounting for herd-level clustering, dry season (OR = 1.5; 95% CI: 1.0, 2.1) and nomadic pastoralism (OR = 1.8; 95% CI: 1.1, 3.2) were associated with increased odds of a camel being exposed to T. evansi infection compared to wet season and ranching, respectively. Following this correction, only nomadic pastoralism was significantly associated (OR = 3.1; 95% CI = 1.0, 14.4) with T. evansi infection compared to ranching. It is concluded that camels managed under nomadic pastoralism had higher risk of being exposed to T. evansi infections than camels from ranching systems of management.