Browsing by Author "Auma, J.E."
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Item A device for restraining mice and confining tsetse flies during trypanosome infection transmission experiments(2013) Ndung’u, K.; Kibugu, J.K.; Gitonga, P.K.; Thuita, J.K.; Auma, J.E.; Gitonga, S.K.; Murilla, G.A.Chemical (anaesthesia) and manual techniques are commonly used to restrain mice during vector-mediated parasite transmission experiments in the laboratory. Chemical restraint may interfere with natural fly vector–mouse interactions and therefore potentially affect the outcome of transmission experiments. Conversely, manual restraint is labour-intensive and exposes laboratory animals to excessive restraining-related discomfort. We report development of a mouse restraining device (Infectra®-kit) that allows essential transmission studies to be carried out with minimal human manipulation and without the need for anaesthesia. Infectra®-kit can be used as a single unit for restraining one mouse or as eight-assembled units, thus significantly improving efficiency of a single operator in comparison to manual restraint. The kit was validated by comparing feeding success in tsetse flies fed on mice restrained using Infectra®-kit (Group I) to those manually restrained (Group II). The mean ± SE % feeding success was 75.0 ± 8.2% and 82.1 ± 8.2% for tsetse flies in Groups I and II respectively. Statistical analysis using two sample t-test showed no significant difference between the two groups at p ≤ 0.05, indicating that Infectra®-kit as a restraining device was as good as the conventional manual restraint method. The main benefits of using Infectra®-kit for transmission studies therefore include reduction of man-hours and animal restraining-related discomfort. In addition, the risk of accidental injury to laboratory personnel by either mice or tsetse flies is minimized, which is an important consideration when working with zoonotic parasites.Item A device for restraining mice and confining tsetse-flies during trypanosome infection transmission experiments(2013) Ndung’u, K.; Kibugu, J.K; Gitonga, P. K.; Thuita, J.K. ; Auma, J.E.; Gitonga, S.K.; Gitonga, S. K.; Murilla, G.A; Kenya Agricultural Research Institute (KARI), Kenya. kariukindungu36@yahoo.comChemical (anaesthesia) and manual techniques are commonly used to restrain mice during vector mediated parasite transmission experiments in the laboratory. Chemical restraint may interfere with natural fly vector-mouse interactions and therefore potentially affect the outcome of transmission experiments. Conversely, manual restraint is labour-intensive and exposes laboratory animals to excessive restraining-related discomfort. We report development of a mouse restraining device (Infectra"-kit) that allows essential transmission studies to be carried out with minimal human manipulation and without the need for anaesthesia. Infectra®-kit can be used as a single unit for restraining one mouse or as eight-assembled units, thus significantly improving efficiency of a single operator in comparison to manual restraint. The kit was validated by comparing feeding success in tsetse flies fed on mice restrained using Infectra®-kit (Group I) to those manually restrained (Group II). The mean ± SE % feeding success was 75.0 ± 8.2% and 82.1 ± 8.2% for tsetse flies in Groups I and II respectively. Statistical analysis using two sample I-test showed no significant difference between the two groups at p ~ 0.05, indicating that Infectra®-kit as a restraining device was as good as the conventional manual restraint method. The main benefits of using Infectra®-kit for transmission studies therefore include reduction of man-hours and animal restraining-related discomfort. In addition, the risk of accidental injury to laboratory personnel by either mice or tsetse flies is minimized, which is an important consideration when working with zoonotic parasites.Item Effect of aflatoxin Bl on the therapeutic efficacy of suramin in Trypanosoma brucei rhodesiense-infected mice(2011) Kibugu, J.K.; Mdachi, R.E.; Kagira, J.M.; Muchiri, M.W.; Makumi, J.N.; Ngeranwa, J.J.N.; Auma, J.E.; Ngae, G.N.; Kenya Trypanosomiasis Research Institute; Kenya Agricultural Research Institute(KARI), Trypanosomiasis Research Centre (TRC), Kikuyu Kenya, Kenyatta University Department of Biochemistry and Biotechnology, Nairobi, Kenya, KARI, Agricultural Centre-MugugaThrough immuno-suppression, aflatoxins could affect drug and vaccine efficacy. Such effects have not been evaluated in treatment of many diseases including trypanosomiasis. We assessed the effect of aflatoxin B 1 on the efficacy of suramin, the drug used for treatment of early stage sleeping sickness, in a murine model. Mice were fed daily on a diet containing 0.50 mg aflatoxin/kg body weight or a placebo. They were infected with Trypanosoma brucei rhodesiense on day 7 post-aflatoxin exposure and then treated with one of 6 different doses of suramin (4.0, 4.5, 5.0, 5.5, 6.0 and 6.5 mg/kg body weight) at the onset of parasitemia. The mice were fed on aflatoxin diet for 30 days and the curative dose values (CD 50, 75. and 90) computed and compared using a logistic linear regression model. Aflatoxin B 1 induced transient protection of the host against T. b. rhodesiense infection and a consistent increase in suramin CD values in the mice suggesting reduced drug efficacy. Aflatoxicosis hindered curative treatment of T. b. rhodesiense infection in mice, and may contribute to reduced efficacy of suramin during treatment of sleeping sickness in man.Item Epidemiology of Drug Resistant Trypanosoma Evansi Isolates From Camels in Kenya(1996) Maina, W.N.N.; Otieno, C.; Wesongah, J.O.; Auma, J.E.; Nyang'oa, J.M.N.; Olaho-Mukami, W.; Sutherland, D.V.; Kenya Trypanosomiasis Research Institute; Kenya Trypanosomiasis Research Institute, Kikuyu, KenyaThe sensitivity patterns of 22 Trypanosoma evansi isolates collected from camel herds in four districts of Kenya to melarsomine, suramin and trypacide were assessed in vitro. Trypanosome metabolism was determined by direct counting method and measurement of pyruvate levels. Eighteen isolates (85.5%) were sensitive to melarsomine with IC.o values in the range 3-35 ng/ml, while three isolates (14.5%) showed reduced sensitivity to melarsomine (lC.o 50-500 ng/ml). Resistance to trypacide was observed in twelve Isolates (58%) at 500 ng/ml, while eight isolates (38%) were resistant to suramin at 10 I1g/ml. Only six isolates (29%) were resistant to both trypacide and suramin. The isolates from Isiolo were all resistant to trypacide, while two (50%), one (25%) and one (20%) isolates from Tana River, Marbasit and Laikipia, respectively, were resistant at 500 ng/m/. All the isolates from Laikipia were sensitive to suramin (IC.o 0.06 - 3 I1g/ml) while five (63%), two (50%) and one (25%) isolates collected from Isiolo, Tana River and Marsabit, respectively were resistant at 10 1l9/ml. Similar sensitivity patterns were revealed by the pyruvate method and direct counting method. However, the pyruvate method was more reproducible, and capable of screening large number of samples.Item Epidemiology of Drug Resistant Trypanosoma Evansi Isolates from Camels in Kenya(1990) Maina, W.N.N.; Otieno, C.; Wesongah, J.O; Ngatia, P.N.; Auma, J.E.; Onyango, J.M.N.; Olaho-Mukami, W.; Sutherland, D.V.; Kenya Trypanosomiasis Research Institute; Kenya Trypanosomiasis Research Institute, Kikuyu, KenyaThe sensitivity patterns of 22 Trypanosoma evansi isolates collected from camel herds in four districts of Kenya to melarsomine, suramin and trypacide were assessed in vitro. Trypanosome metabolism was determined by direct counting method and measurement of pyruvate levels. Eighteen isolates (85.5%) were sensitive to melarsomine with IC.o values in the range 3-35 ng/ml, while three isolates (14.5%) showed reduced sensitivity to melarsomine (IC.o 50-500 ng/ml). Resistance to trypacide was observed in twelve isolates (58%) at 500 ng/ml. while eight isolates (38%) were resistant to suramin at 10 119/ml. Only six isolates (29%) were resistant to both trypacide and suramin. The isolates from Isiolo were all resistant to trypacide, while two (50%), one (25%) and one (20%) isolates from Tana River, Marbasit and Laikipia, respectively, were resistant at 500 ng/ml. All the isolates from Laikipia were sensitive to suramin (IC.o 0.06 - 3 fAg/ml) while five (63%), two (50%) and one (25%) isolates collected from Isiolo, Tana River and Marsabit, respectively were resistant at 10 119/ml. Similar sensitivity patterns were revealed by the pyruvate method and direct counting method. However, the pyruvate method was more reproducible, and capable of screening large number of samples.Item Infectra-kit: A device for restraining mice and confining tsetse flies during trypanosome infection transmission experiments(2013) Ndungu, K.; Kibugu, J. K.; Gitonga, P. K; Thuita, J. K.; Auma, J.E.; Gitonga, S. K.; Ngae, G. N.; Murilla, G. A.; Kenya Trypanosomiasis Research Institute; Kenya Agricultural Research Institute (KARI), KenyaChemical(anaesthesia) and manual techniques are commonly used to restrain mice during vector mediated parasite transmission experiments in laboratory. Chemical restrain may interfere with natural fly vector-mouse interactions and therfore potentially affect the outcome of transmission experiments. Conversely, manual restraint is labour-intensive and exposes laboratory animals to excessive restraining- related discomfort. We report development of a mouse restraining device (infectra-kit)that allows essential transmission studies to be carried out with animal human manipilation and without the need for anaesthesia. Infectra- kit can be used as a single unit for restraining one mouse or as eight- assmbled units, thus significantly improving effeciency of a single operator in comparision to manual restraint. The kit was validated by comparing feeding success in tsetse flies fed on mice restrained usning infectra-kit(group 1 )to those manually restrained (group II). The mean +SE% feeding sucess was 75.0+8.2% for tsestse flies in Groups I and II respectively. Statistical analysis using two sample, test showed no significant difference between the two groups at p< 0.05, indicating that infectra -kit as restraining device was as good as the conventional manual restraint method. The main benefits of using infectra-kit for transmission studies therfore include reduction of man- hours and animal restrainining-related discomfort, which is an important consideration when working with zoonotic parasites.Item Spatial–Temporal Variations in Parasitological Prevalence and Host-Related Risk Factors of Camel Trypanosomiasis and Its Vectors in North Eastern Kenya: A Repeated Cross-Sectional Study(Hindawi, 2023-04-28) Ogolla, K.O.; Chemuliti, J.K.; Wamwiri, F.N.; Auma, J.E.; Kurgat, R.K.; Wanjala, K.B.; Mugunieri, L.G.; Alusi, P.M.; Mdachi, R.E.; Mukiria, P.W.; Okoth, S.O.; Kenya Agricultural and Livestock Research Organization ; East African Science and Technology Commission (EASTECO)/East African CommunityCamel trypanosomiasis (Surra) is endemic in the Horn of Africa. Understanding the spatiotemporal variations in Surra prevalence, vector dynamics, and host‐related risk factors is important in developing effective control strategies. A repeated cross‐sectional study was conducted to determine the Surra parasitological prevalence, livestock reservoirs, vector density/diversity, and host‐related risk factors in Kenya. Random samples of 847, 1079, and 824 camels were screened at the start of the dry season, peak dry season, and during the rainy season, respectively. Blood samples were examined using the dark ground/phase contrast buffy‐coat technique, and Trypanosoma species were identified based on their movement and morphology in wet and stained thin smears. Reservoir status for Trypanosoma evansi was assessed in 406 cattle and 372 goats. A rainy and dry seasons entomological surveys were conducted to determine the Surra vector abundance/diversity and spatiotemporal density changes. Surra prevalence was 7.1%, 3.4%, and 4.1% at the start of the dry season, peak dry season, and rainy season, respectively. Camel co‐infections by Trypanozoon (T. evansi or Trypanosoma brucei brucei) and Trypanosoma vivax were recorded. Spatial variations in Surra prevalence were recorded at the beginning of dry (X7846,N=2=110.9, p ≤ 0.001), peak dry (X71079,N=2=42.2, p ≤ 0.001), and rainy (X7824,N=2=29.1, p ≤ 0.001) seasons. The screened cattle and goats tested negative for Trypanozoon (T. evansi or T. b. brucei), while two cattle tested positive for Trypanosoma congolense. Biting fly catches were composed of a single species from Tabanus, Atylotus, Philoliche, Chrysops, and Stomoxys genera. The total catches for Philoliche, Chrysops, and Stomoxys were higher in the rainy than dry season consistent with the prevalence results. Surra remains an important camel disease in the region with its prevalence varying in space and time. Camel co‐infections by Trypanozoon (T. evansi or T. b. brucei) and T. vivax necessitate proper diagnosis of suspected cases and targeted therapy.Item Variation of Sensitivity of Trypanosoma evansi Isolates from Isiolo and Marsabit Counties of Kenya to Locally Available Trypanocidal Drugs(PLoS One, 2023-02-02) Mdachi, R.E.; Ogolla, K.O.; Auma, J.E.; Wamwiri, F.N.; Kurgat, R.K.; Wanjala, K.B.; Mugunieri, L.G.; Chemuliti, J.K.; Mukiria, P.W.; Okoth, S.O.; Kenya Agriculture and Livestock Research Organization; East African Science and Technology Commission (EASTECO)\East African Community, Kigali, RwandaTrypanocidal resistance is a major cause of treatment failure. This study evaluated the sensitivity of Trypanosoma evansi field isolates collected from Marsabit and Isiolo counties, Kenya. A total of 2,750 camels were screened using parasitological tests for trypanosomes. Of the screened camels, 113 tested positive from which 40 T. evansi isolates were tested using the single dose mice sensitivity test. Five treatment groups each comprising of 6 mice were inoculated intraperitoneally with 1x105 trypanosomes of each isolate and treated 24 hours later with isometamidium chloride at 1 mg/kg, homidium chloride at 1mg/kg, diminazene aceturate at 20 mg/kg and quinapyramine sulphate & chloride at 1 mg/kg. The fifth group was left untreated (positive control). The mice were monitored daily for 60 days. A survey on camel owners’ practices that influence development of resistance to trypanocidal drugs was then conducted. Results indicated presence of drug resistance in all the 7 study sites that had infected camels. Seven of the isolates tested were resistant to diminazene aceturate whereas, 28, 33 and 34 were resistant to isometamidium chloride, quinapyramine sulphate & chloride and homidium chloride, respectively. Seven (17.5%) isolates of the 40 tested were sensitive to all 4 drugs, whereas, 7.5%, 10%,55% and 10% were resistant to 1,2,3 and 4 drugs, respectively. The prevalence of multiple drug resistance was 75%. Survey data indicated that camel management practices influenced the prevalence and degree of drug resistance. In conclusion, the multiple drug resistance observed in the two counties may not be an indication of total trypanocidal drug failure. Judicious treatment of confirmed trypanosomiasis cases with correct dosage would still be effective in controlling the disease since the observed resistance was at the population and not clonal level. However, integrated control of the disease and the vectors using available alternative methods is recommended to reduce drug use.Item Xanthine Oxidase In Rat Diabetic Tissues Cheiluminescence Assay(Joanna E. Auma, 1991) Auma, J.E.Active oxygen free radicals have been implicated in diabetes. Type I diabetes is caused by destruction of beta cells responsible for production of insulin Diabetes in humans appears to be caused by immune destruction of the beta cells. In animals diabetes can be produced using the drugs a lloxan and streptozotocin. Not only are oxygen free radicals involved in the cause of diabetes, they also appear to playa role in some of the complications seen in long term treatment of diabetes.
