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Full-Text Articles in Diseases

Trypanosome Infection Rates In Tsetse Flies (Diptera: Glossinidae) And Cattle During Tsetse Control Operations In The Kagera River Region Of Rwanda, Steve Mihok, Leonard H. Otieno, Christopher S. Tarimo Jan 1992

Trypanosome Infection Rates In Tsetse Flies (Diptera: Glossinidae) And Cattle During Tsetse Control Operations In The Kagera River Region Of Rwanda, Steve Mihok, Leonard H. Otieno, Christopher S. Tarimo

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Trypanosome infections were monitored in three species of tsetse fly (Glossina pallidipes Austen, G. morsitans centralis Machado, and G. brevipalpis News-tead) at four locations in the Kagera River region of Rwanda from May 1989 to September 1990. Two of the four areas (Mpanga Ranch and Bukora Ranch) were subjected to tsetse fly suppression operations with odour-baited traps. Proboscis infections of the Trypanosoma congolense and T. vivax types accounted for roughly equal numbers of the 207 mature infections detected (3.8%). Variation in infection rates was area-specific rather than tsetse species-specific. Order of magnitude differences in tsetse fly densities among areas were …

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Studies On Tsetse Midgut Factors That Induce Differentiation Of Bloodstream Trypanosoma Brucei Brucei In Vitro, M. O. Imbuga, E. O. Osir, V. L. Labongo, N. Darji, L. H. Otieno Jan 1992

Studies On Tsetse Midgut Factors That Induce Differentiation Of Bloodstream Trypanosoma Brucei Brucei In Vitro, M. O. Imbuga, E. O. Osir, V. L. Labongo, N. Darji, L. H. Otieno

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An in vitro system for studying the transformation of bloodstream forms of Trypanosoma brucei brucei into procylic (midgut) forms is described. In this system, transformation of the parasites was stimulated by Glossina morsitans morsitans midgut homogenates at 27° C but not at 4° C. The transformation-stimulating capacity was irreversibly destroyed by heating the midgut homogenates at 60° C for 1 h. A correlation was established between the transformation activity of the midgut homogenates and trypsin activity. The protease inhibitors (soybean trypsin inhibitor and N-p-tosyl-l-lysine-chloromethyl-ketone) inhibited trypsin activity and completely blocked the transformation of the parasites. Furthermore, the midgut homogenates could …

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Influence Of D(+)-Glucosamine On Infection Rates And Parasite Loads In Tsetse Flies (Glossina Spp.) Infected With Trypanosoma Brucei, Steve Mihok, Leonard H. Otieno, Nafisa Darji, David Munyinyi Jan 1992

Influence Of D(+)-Glucosamine On Infection Rates And Parasite Loads In Tsetse Flies (Glossina Spp.) Infected With Trypanosoma Brucei, Steve Mihok, Leonard H. Otieno, Nafisa Darji, David Munyinyi

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Teneral Glossina morsitans centralis, G. m. morsitans and G. pallidipes were infected with three different clones of Trypanosoma brucei in blood containing d(+)-glucosamine, an inhibitor of tsetse midgut lectin. On average, 5 days of d(+)-glucosamine treatment tripled infection rates, without affecting the proportion of infections that matured. Total infection rates were equal in males and females, but twice as many infections matured in males. Counts of parasites in the guts and salivary glands of 277 flies revealed order of magnitude differences among flies, with females consistently having 2-3-times as many parasites as males. Parasite numbers varied in a sex-specific manner …

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Laboratory And Field Observations On Anti-Tick Properties Of The Plant Gynandropsis Gynandra (L.) Brig, M. M. Malonza, O. O. Dipeolu, A. O. Amoo, S. M. Hassan Jan 1992

Laboratory And Field Observations On Anti-Tick Properties Of The Plant Gynandropsis Gynandra (L.) Brig, M. M. Malonza, O. O. Dipeolu, A. O. Amoo, S. M. Hassan

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A shrubby plant, abundant in east Kenya, Gynandropsis gynandra (L.) Brig., was shown to exhibit repellent and acaricidal properties to larvae, nymphs and adult Rhipicephalus appendiculatus and Amblyomma variegatum ticks. All stages of ticks avoided the leaves of the plant and a high percentage of the ticks which were continuously exposed to its leaves died; surviving ticks were weak and inactive but regained activity when exposed to fresh air. The effectiveness of the plant's leaves as a repellent and acaricide was most pronounced on nymphs and least pronounced on adults. Field investigations indicated that ticks were not found up to …

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Predation Of Free-Living Engorged Female Rhipicephalus Appendiculatus, Esther N. Mwangi, Robin M. Newson, Godwin P. Kaaya Oct 1991

Predation Of Free-Living Engorged Female Rhipicephalus Appendiculatus, Esther N. Mwangi, Robin M. Newson, Godwin P. Kaaya

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In experiments done over a period of 1 1/2 years using engorged female Rhipicephalus appendiculatus tethered in a grass plot, 42% predation was observed in long grass (40-60 cm), and 36% in short grass (6-10 cm). Deaths due to environmental factors were 4.8% and 6.8% in long and short grass, respectively. Six groups of animals were confirmed to be predators of the ticks, namely: ants, spiders, rodents, birds, lizards and shrews. The implications of these results in making tick population models, and the possibility of using predators in integrated tick-control packages are discussed. © 1991 Elsevier Science Publishers B.V.

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Infection Rates In Glossina Morsitans Morsitans Fed On Waterbuck And Boran Cattle Infected With Trypanosoma Congolense, Steve Mihok, Reardon O. Olubayo, David F. Wesonga Jan 1991

Infection Rates In Glossina Morsitans Morsitans Fed On Waterbuck And Boran Cattle Infected With Trypanosoma Congolense, Steve Mihok, Reardon O. Olubayo, David F. Wesonga

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Teneral Glossina morsitans morsitans were fed on waterbuck (Kobus defassa) and Boran cattle (Bos indicus) infected experimentally with Trypanosoma congolense clone IL2895. Infection rates in tsetse varied from 9 to 31% when fed on cattle, and from 2 to 59% when fed on waterbuck. In waterbuck, infections were often detected through the development of parasites in tsetse at times when parasitaemia could not be detected through microscopic examination of blood. Male and female, and 1- and 2-day-old flies were equally susceptible to infection on both hosts. Infection in tsetse was associated with a 14% absolute reduction in survival during the …

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Pathogenicity Of Tsetse-Transmitted Trypanosoma Congolense For Waterbuck (Kobus Defassa) And Boran Cattle (Bos Indicus), R. O. Olubayo, S. Mihok, D. F. Wesonga, E. R.M. Mbwabi Jan 1991

Pathogenicity Of Tsetse-Transmitted Trypanosoma Congolense For Waterbuck (Kobus Defassa) And Boran Cattle (Bos Indicus), R. O. Olubayo, S. Mihok, D. F. Wesonga, E. R.M. Mbwabi

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Five waterbuck (Kobus defassa) and four Boran cattle (Bos indicus) were infected with Trypanosoma congolense IL2895 using Glossina morsitans morsitans. At the same time, two waterbuck and two cattle were inoculated intravenously with bloodstream forms. With both methods of challenge, cattle had short prepatent periods followed by a continuous high parasitaemia. All cattle became severely anaemic and had to be treated with trypanocidal drugs to prevent death. In contrast, tsetse and intravenous challenge of waterbuck resulted in a long prepatent period, followed by brief, intermittent levels of low parasitaemia, and eventual selfcure. Waterbuck did not become anaemic, even during short …

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Tip-Recording From Ixodid Tick Olfactory Sensilla: Responses To Tick Related Odours, S. M. Waladde Dec 1982

Tip-Recording From Ixodid Tick Olfactory Sensilla: Responses To Tick Related Odours, S. M. Waladde

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The tip-recording technique was used to obtain electrophysiological responses from the tarsal olfactory sensilla, md3 and apl, in ixodid ticks, Rhipicephalus appendiculatus and Amblyomma variegatum. Stimuli tested were phenolic compounds, 2,6-dichlorophenol, P-cresol, phenol and salicylaldehyde, reported to act as sex pheromone of various ixodid ticks. Certain cells responded to vapours from cartridges charged with as little as 0.04ng of 2,6-dichlorophenol while at least 200 μg of any of the other compounds was required to exert the minimum effect. Response patterns of cells in sexually immature and mature males were similar but response levels were higher among sexually immature males. Vapours …

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