Browsing by Author "Ndungu, J. M."
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Item Detection of Trypanosoma brucei rhodesiense in animals from sleeping sickness foci in East Africa using the serum resistance associated (SRA) gene(2004) Njiru, Z. K.; Ndungu, J. M.; Ndungu, K.; Matete, G.; gibson, C. W.; Kenya Trypanosomiasis Research Institute (KETRI), P.O. Box 362, Kikuyu, Kenya School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UKThe human serum resistance associated (SRA) gene has been found exclusively in Trypanosoma brucei rhodesiense, allowing the unequivocal detection of this pathogen in reservoir hosts and the tsetse vector without recourse to laborious strain characterisation procedures. We investigated the presence of the SRA gene in 264 T. brucei ssp. isolates from humans, domestic animals and Glossina pallidipes from foci of human trypanosomiasis in Kenya and Uganda. The SRA gene was present in all isolates that were resistant to human serum, and absent from all serum sensitive isolates tested. Further, the gene was present in all isolates that had previously been shown to be identical to human infective trypanosomes by isoenzyme characterisation. The SRA gene was detected in isolates from cattle, sheep, pigs, dog, reedbuck, hyena and G. pallidipes from sleeping sickness foci, but was not found in Trypanosoma evansi or in Trypanosoma brucei gambiense isolates. The present study indicates that the SRA gene may be invaluable in detecting and differentiating T. brucei rhodesiense from other T. brucei ssp. in reservoir hosts and tsetse.Item Elevation of the concentration of acute phase proteins in dogs infected with Trypanosoma brucei(1991) Ndungu, J. M.; Eckersall, P.D.; Jennings, F. W.; Kenya Trypanosomiasis Research Institute; Department of Veterinary Medicine, University of Glasgow, Bearsden Road, Bearsden, Glasgow G61 1QH, U.K.Plasma concentrations of the acute phase proteins (APP), C-reactive protein (CRP) and haptoglobin (Hp), increased markedly following experimental infection of dogs with Trypanosoma brucei. The highest concentrations of CRP were observed immediately after peaks of parasitaemia. Treatment with curative doses of the trypanocidal drug suramin caused a rapid decrease in CRP. Relapse infections after subcurative treatment were followed by a reappearance of high plasma CRP concentrations. Haptoglobin remained elevated during the course of the disease. Curative treatment with suramin caused a gradual but slow decrease in Hp while subcurative treatment caused no significantly changes. Thus, the estimation of CRP was useful in determining the presence of active infection and the success of chemotherapy. High Hp levels in severely anaemic dogs indicated that intravascular haemolysls does not contribute significantly to the anaemia associated with T. brucei infections in dogs. These conclusions need confirmation from a larger experiment.Item Identification of trypanosomes in Glossina pazzidipes and G. longipennis in Kenya(2004) Njiru, Z. K.; Makumi, J. N.; Okoth, S. O.; Ndungu, J. M.; gibson, C. W.; Kenya Trypanosomiasis Research Institute (KETRI), P.O. Box 362, Kikuyu, Kenya School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK Division of Health Sciences, School of Veterinary and Biomedical Sciences, Murdoch University, South Street, WA 6150, AustraliaThe polymerase chain reaction (PCR) was used to identify trypanosomes in Glossina pallidipes and C. longipennis caught in Kenya. Of 3826 flies dissected, 188 (4.9%) were parasitologically positive overall. The infection rate in C. pallidipes was 5.7% (187 of 3301 flies), but only one of 525 C. longipennis was infected (infection rate 0.2%). There was a higher infection rate in female C. pallidipes flies than male flies (X2 = 18.5, P < 0.001) and odds ratio = 2.5 (95% 1.6, 3.7). The infected flies were analysed by PCR using 10 sets of primers specific for species and subgroups within the subgenera Nannomonas, Trypanozoon and Duttonella. Of 188 parasitologically positive samples, PCR identified 137 (72.9%), leaving 51 (27.1 %) non-identified. We recorded infection rates of 47.2% for Trypanosoma congolense savannah, forest and kilifi subgroups, 20.9% for T. simiaelT. Simiae tsavo/T. godfreyi, 14.9% for T. brucei ssp. and 13.8% for T. vivax. Thirty-nine (26.7%) flies had mixed infections, with a minor association between T. congolense savannah/to simiae tsavo/T. godfreyi (X2 = 6.93, dJ. = I, P < 0.05). The relative proportion of each trypanosome species or subgroup varied between fly belts with T. congolense (all subgroups) being the most abundant and T. godfreyi the least. Statistical analysis showed that dissection method and PCR test classified infections independently (X2 = 10.5, d.f. = I, P < 0.05 and K = 0.38). This study shows that pathogenic trypanosomes are widespread in all sampled testes fly belts with C. pallidipes as the main vector. Further, PCR test is more reliable in detecting and identifying trypanosomes than dissection method.Item Isolation and propagation of Trypanosoma Bruce gambiense from sleeping sickness patients in south Sudan(2007) Naomi, W. N.; Oberle, M.; Otieno, C.; Kunz, C.; Maeser, P.; Ndungu, J. M.; Brun, R.; Kenya Trypanosomiasis Research InstituteThis study aimed at Isolating Trypanosoma brucei gamblense from human African trypanosomiasis (HAT) patients from south Sudan. Fifty HAT patients Identified during active screening surveys were recruited, most of whom (49/50) were in second-stage disease" Blood and cerebrospinal fluid samples collected from the patients were cryopreserved using Tryadyl as the cryomedium. The samples were stored at -150' C In liquid nitrogen vapour in a dry shipper. Eighteen patient stablates could be propagated in Immunosuppressed Mastomys natalensis and/or SCID mice. Parasitaemia was highest In SCID mice. Further subpassages In M. natalensis increased the virulence of the trypanosomes and all 18 isolates recovered from M. natalensis or SCID mice became infective to other immunosuppressed mouse breeds" A comparison of Immunosuppressed M. nataiensis and Swiss White, C571BL and BALBlc mice demonstrated that all rodent breeds were susceptible after the second subpassage and developed a parasitaemia >106/ml by Day 5 post infection. The highest parasitaemias were achieved in C571BL and BALB/c mice. These results indicate that propagation of T. b" gambiense isolates after Initial isolation In Immunosuppressed M. natalensis or SCID mice can be done in a range of Immunosuppressed rodents.Item The performance of Orma Boran and Maasai Zebu crossbreeds in a trypanosomosis endemic area of Nguruman, south western Kenya(2005) Maichomo, M. W.; Ndungu, J. M.; Ngare, P. M.; Ole-Mapeny, I. M.; Kenya Trypanosomiasis Research InstituteStudies on the trypanotolerance of Orma Boran X Maasai Zebu (Orma Zebu) crossbred cattle (Fl progeny) and pure-bred Maasai Zebu contemporaries were earned out In Nguruman, south western Kenya. The two groups were monitored from birth for a period of 2 years. The incidence of trypanosomosis, parasitaemia, packed cell volume (PCV), body mass and average daily mass gain were monitored. During the study period, overall trypanosomosis incidence was low (3 %). The crossbred cattle had a higher incidence of infection (61 % vs 39 %). The mean PCV and mean mass gain for the crossbred cattle was higher than that of the Maasai Zebu. The mean calf body mass at weaning (8 months) for the Orma Zebu and Maasai Zebu was 72 kg and 64 kg, respectively, while at 18 months of age their mean body mass was 164 kg and 123 kg, respectively. During the rainy season significant differences in average dally mass gains were noted (P< 0 05). The superior mass gain of the Orma Zebu observed during the rainy season, despite higher infection rates, indicate an enhanced trypanotolerance. Moreover, the better performance of the Orma Zebu IS an attribute that could be exploited in the adoption of the trypanotolerance genotype, as a sustainable trypanosomosis control strategy.Item Unravelling the phylogenetic relationships of African trypanosomes of suids(2001) Gibson, W. C.; Stevens, J. R.; Mwendia, C. M. T.; Makumi, J. N.; Ngotho, J. M.; Ndungu, J. M.; Kenya Trypanosomiasis Research Institute; School of Biological Sciences, University of Bristol, Bristol BS8 1UG, Affiliation: Kenya Trypanosomiasis Research Institute, PO Box 362, Kikuyu, KenyaAfrican trypanosomes of the subgenera Nanomonas and Pycnomonas ha\'e been recorded from both wild and domestic suids. However, complete descriptions of some of these trypanosomes with regard to host range, pathogenic, transmission and distribution are stilliackmg. Either the recently described Trypanosoma (Nannomonas) godfreyi or Trypanosoma (Nannomonas) congoiense Tsavo have been isolated from mammalian hosts, while Trypanosoma (Pyonononas) Suis remains the rarest of the Salivarian trypanosomes. The only isolate presumed to be of the latter species is maintained at the Kenya Trypanosomiasis Research Institute, Nairobi. We present here the results of characterization of this isolate by morphology, tsetse transmission, the use of species-specific DNA probes and DNA sequence analysis. Morphology in stained blood smears revealed a small trypanosome with a free flagellum. Experimental transmission through Glossinaa morsltans 1norsitans showed a developmental cycle typical of subgenus nanomonas. A positive identification was obtained with species-specific PCR primers for T. congelencese Tsavo; moreover, the sequence of the SSU rRNA gene \vas almost identical to that of T. congolense Tsavo on database. In phylogenetic analysis of the SSP rRNA genes of SaliYarian trypanosomes, T. congolense Tsavo grouped with T. simiae rather than T. congolense, suggesting that the name T. simiae Tsavo is more appropriate.
