Characterisation of the Wildlife Reservoir Community for Human and Animal Trypanosomiasis in the Luangwa Valley, Zambia

Animal and human trypanosomiasis are constraints to both animal and human health in Sub-Saharan Africa, but there is little recent evidence as to how these parasites circulate in natural hosts in natural ecosystems. A cross-sectional survey of trypanosome prevalence in 418 wildlife hosts was conducted in the Luangwa Valley, Zambia, from 2005 to 2007. The overall prevalence in all species was 13.9%. Infection was significantly more likely to be detected in waterbuck, lion, greater kudu and bushbuck, with a clear pattern apparent of the most important hosts for each trypanosome species. Human infective Trypanosoma brucei rhodesiense parasites were identified for the first time in African buffalo and T. brucei s.l. in leopard. Variation in infection is demonstrated at species level rather than at family or sub-family level. A number of significant risk factors are shown to interact to influence infection rates in wildlife including taxonomy, habitat and blood meal preference. Trypanosoma parasites circulate within a wide and diverse host community in this bio-diverse ecosystem. Consistent land use patterns over the last century have resulted in epidemiological stability, but this may be threatened by the recent influx of people and domesticated livestock into the mid-Luangwa Valley

Long-Lost Relative Claims Orphan Gene: oskar in a Wasp

Organismic and Evolutionary Biolog

Quantifying Heterogeneity in Host-Vector Contact: Tsetse (Glossina swynnertoni and G. pallidipes) Host Choice in Serengeti National Park, Tanzania

Identifying hosts of blood-feeding insect vectors is crucial in understanding their role in disease transmission. Rhodesian human African trypanosomiasis (r-HAT or ‘sleeping sickness’) caused by Trypanosoma brucei rhodesiense and transmitted by tsetse flies, is commonly associated with wilderness areas of east and southern Africa. Such areas hold a diverse range of species which form communities of hosts for disease maintenance. The relative importance of different wildlife hosts remains unclear. This study quantified tsetse feeding preferences in a wilderness area of great host species richness, Serengeti National Park, Tanzania, assessing tsetse feeding and host density contemporaneously. Glossina swynnertoni and G.pallidipes were collected from six study sites. Bloodmeal sources were identified through matching Cytochrome B sequences amplified from bloodmeals from fed flies to published sequences. Densities of large mammal species in each site were quantified, and feeding indices calculated to assess the relative selection or avoidance of each host species by tsetse. The host species most commonly identified in G. swynnertoni bloodmeals, warthog (94/220), buffalo (48/220) and giraffe (46/220), were found at relatively low densities (3-11/km2) and fed on up to 15 times more frequently than expected by their relative density. Wildebeest, zebra, impala and Thomson’s gazelle, found at the highest densities, were never identified in bloodmeals. Commonly identified hosts for G. pallidipes were buffalo (26/46), giraffe (9/46) and elephant (5/46). This study is the first to quantify tsetse host range by molecular analysis of tsetse diet with simultaneous assessment of host density in a wilderness area. Although G.swynnertoni and G.pallidipes can feed on a range of species, they are highly selective. Many host species are rarely fed on, despite being present in areas where tsetse are abundant. These feeding patterns, along with the ability of key host species to maintain and transmit T.b.rhodesiense, drive the epidemiology of r-HAT in wilderness areas

Trophic State in Canterbury Waterways

Aquatic eutrophication is a serious global problem, associated with phytoplankton blooms, hypoxia, and loss of species. The objective of this thesis was to advance understanding of stream and lake eutrophication within Canterbury (South Island, New Zealand). I investigated three key questions: 1) How do riparian characteristics control stream trophic state, 2) how does stream trophic state in the Canterbury region compare to stream trophic state nationally and internationally, and 3) what factors control trophic state in Te Wairewa/Lake Forsyth. I measured rates of stream community metabolism in 21 Canterbury streams over a gradient of riparian canopy cover, and conducted a literature review of national and international studies of stream metabolism. I also examined the occurrence of cyanobacterial blooms in Te Wairewa in relation to water quality and weather from 17 years of measurements, and performed series of nutrient addition assays on the lake to assess nutrient limitation. I found that riparian characteristics strongly controlled stream trophic state by shading, thereby reducing photosynthetic productivity. This overwhelmed the effects of high nitrate concentrations, which increased primary production. Compared to national and international rates of stream metabolism, Canterbury streams were strongly heterotrophic, with low rates of autotrophic production. Catchment streams draining into Te Wairewa were unlikely to be the main source of nutrients supporting large cyanobacterial blooms. Instead, internal lake nutrient loading mechanisms associated with calm weather were likely to supply blooms. My results emphasize the importance of light limitation, nitrogen and heterotrophy in controlling stream trophic state, and nutrient supply and weather in controlling lake trophic state

Intrathecally administered baclofen for treatment of children with spasticity of cerebral origin

Management of severe spasticity in children is often a difficult problem. Orally administered medications generally offer limited benefits. This study examines the value of intrathecally administered baclofen in the treatment of 19 children with severe spasticity of cerebral origin: eight of whom sustained brain injury associated with trauma, near drowning, or cardiac arrest; 10 with cerebral palsy (spastic quadriplegia); and one child with Leigh\u27s disease. At the time of entry into the study, patients ranged from 4 to 19 years of age, and all were completely dependent on caretakers for activities of daily living. Children who responded positively to a trial dose of intrathecal baclofen underwent insertion of a drug delivery system for continuous infusion. This was followed by a double-blind trial of baclofen or placebo and follow-up review at 3 and 6 months, and yearly thereafter. Seven children did not undergo pump implantation because of excess sedation or poor response. The 12 remaining children have been followed for a period of 1 to 5 years. Favorable responses were present in all 12 children as determined by the Ashworth Scale, with the greatest benefit being reduction of lower limb tone. Except in the case of one child who had reduction in lower limb tone that resulted in difficulty with transfers, the caretakers all reported significant benefits from intrathecal baclofen, with improvement in muscle tone, behavior, sitting, and general ease of care being most commonly noted. Central side effects were seen in some children who received continuous intrathecal baclofen infusion and included hypotension (two patients), bradycardia (two), apnea or respiratory depression (two), and sedation (one). During a total of 568 months of pump operation there were 10 mechanical complications, including two related to pump or side port failure and eight related to catheter kinks, extrusions, or dislodgment. Pump pocket effusion occurred in five children and a cerebrospinal fluid fistula was seen in one child. Local infection occurred in three children and meningitis in two children. The results demonstrate the potential value of continuous intrathecal baclofen infusion for treatment of severe spasticity of cerebral origin. However, this treatment can result in significant complications and more experience is required before the long-term benefits can be determined