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Item East Coast Fever Immunisation Trials in Uganda: Field Exposure of Zebu Cattle Immunized with Three Isolates of Theileria Parva(Tropical Animal Health and Production, 1977) Robson, J.; Odeke, G G. M.; Kamya, E. P.; Brown, C. G. D.Zebu cattle were immunised against East Coast fever (ECF) using three isolates ofTheileria parva inoculated as cryopreserved stabilates of infective particles harvested fromRhipicephalus appendiculatus. These isolates included the East African laboratory type strain,T. parva (Muguga), and two isolates ofT. parva from Entebbe, Uganda. Pairs of cattle received an inoculation of stabilate and were allowed to react and recover fortuitously, while groups of five cattle received both stabilate and were protected by chemoprophylactic therapy with oxytetracycline. An IFA serological response was elicited in 17 of the 21 stabilate recipients. These 21 cattle, along with eight susceptible controls, were exposed to a massive and continuing natural challenge ofT. parva andT. mutans, accompanied by very heavy tick infestation in an ECF enzootic area at Kigungu, Entebbe. All eight controls died of ECF in a mean time of 25·6 days. The stabilate recipients were significantly protected, their mean time to death being 71·3 days. Only six of these 21 cattle died of theileriosis within 40 days of exposure and these included three which did not exhibit a serological response following inoculation of stabilate. The implications ofT. mutans pathogenesis, unlimited heavy tick challenge and the potential value of complexes ofT. parva strains are discussed.Item Dose Response Relationship of Haemophilus pleuropneumoniae Aerosols in Pigs(Canadian Journal of comparative medicine, 1983) Sebunya, T.N.K.; Saunders, J.R.; Osborne, A.D.The virulence of Haemophilus pleuropneumoniae was quantitated for ten and 12 week old pigs following aerosol exposure. The volume and concentration of culture aerosolized, the estimated numbers of organisms inhaled by the pigs and the mortality rates at 72 hours postexposure were computed and used to calculate the LD50. There was correlation between the concentration of culture aerosolized, the amount of the estimated inhaled dose and the mortality rates. The ten week old pigs were apparently more susceptible to aerosols of H. pleuropneumoniae than the 12 week old pigs. The LD50 value or a multiple of it appears to be a reasonable basis for a standardized aerosol challenge of the immunity of pigs vaccinated with experimental or commercial H. pleuropneumoniae vaccines.Item Production of Fumonisins by Fusarium moniliforme and Fusarium proliferatum Isolates Associated with Equine Leukoencephalomalacia and a Pulmonary Edema Syndrome in Swine(Applied and Environmental Microbiology, 1990) Ross, P. F.; Nelson, P. E.; Richard, J. L.; Osweiler, G. D.; Rice, L. G.; Plattner, R. D.; Wilson, T. M.During the 1989 corn harvest season, the National Veterinary Services Laboratories received numerous reports of outbreaks of equine leukoencephalomalacia (ELEM) and a porcine pulmonary edema syndrome (PPE). The PPE outbreaks were generally confined to the central portion of the United States, while ELEM cases in several states, ranging from Arizona to Maryland, were reported. In almost all cases, feed containing corn and/or corn screenings from the 1989 harvest was implicated as the causative factor. Because ELEM is known to be caused by fumonisin B, (FB,) (4), a mycotoxin produced by Fusarium moniliforme, and because a PPE-like syndrome caused by feeding F. moniliforme culture material (CM) to swine has been reported (3), feed samples were collected for mycological evaluation and chemical analyses. Nine feed samples were obtained from farms in southeastern Iowa: two were associated with an ELEM case (284A and 284B), five were associated with PPE cases (943A, 567, 615, 317A, and 378B), and two were not associated with animal health problems (943B and 317B).Item Anaplasmosis in Uganda. II. Prevalence of Bovine Anaplasmosis(Scandinavian Journal of Immunology, 1992) SSENYONGA, G. S. Z.; KAKOMA, I.; MONTENEGRO-JAMES, S.; NYEKO, P. J.; NANTEZA, A.; BUGA, R.The prevalence of bovine anaplasmosis was studied in 320 Zebu cattle randomly selected from three regions of Uganda (central, south-western and north-western) using DOT-ELISA, Western immunoblotting. Rapid Card Agglutination Test (RCAT), Capillary Tube Agglutination Test (CAT), Complement Fixation Test (CFT), and parasitological techniques. Dried blood on Whatman filter paper no. I was eluated in PBS 0.05% Tween 20 prior to testing at an initial dilution of 1:25. The incidence of parasitaemia ranged from 25% in the central region to 35% in the northwestern region and the serological prevalence was lower in the central region and highest in the north-west. Prevalence rates assayed by DOT-ELISA and Western immunoblotting were 1.5-fold greater than those tested with RCAT and 3-fold greater than in CAT. The overall prevalence rates by DOT-ELISA and Western immunoblotting compared favourably with CFT data. The present data utilizing dried blood on filter papers indicate that there is a high prevalence of anaplasmosis in those regions of Uganda surveyed and it confirms our observations and those of others that collecting blood on filter papers is a suitable technique for large-scale screening and for seroepidemiological studies.Item Characterization of the coffee berry disease pathogen, Colletotrichum kahawae sp. nov.(Mycological Research, 1993) Waller, J.M.; Bridge, P.D.; Black, R.; Hakiza, G.A range of Colletotrichum isolates from coffee, including the coffee berry disease (CBD) pathogen, and representative isolates of C. gloeosporioides from some other tropical crops are compared. Isolates of the CBD pathogen taken from across its range of distribution in Africa have common morphological, biochemical and pathogenic characteristics. These distinguish them from other Colletotrichum isolates. The nomenclature of the CBD pathogen, often referred to as a form of C. coffeanum, is confused. Its taxonomic position is discussed and the new species name Colletotrichum kahawae is introduced.Item Wind-Tunnel Studies on the Collection of Airborne Spray Droplets by Flying Locusts(International Journal of Tropical Insect Science, 1994) Ndayanbo-Mugisha, FrankIn view of the present environmental awareness, the reduction of spray wastage, which in turn lessens environmental contamination, can be achieved by reducing spray volumes and improvement on spray efficiency through the use of correct ranges of spray droplet sizes. Published data on droplets collected by some insects consistently suggest that the optimum droplet sizes lie below 60 μm. An experiment was conducted in a wind-tunnel to assess the locust collection efficiency when subjected to a spectrum of droplet size ranges with a view to determine the optimum droplet size. Locusts were induced to fly in a wind-tunnel and then exposed to spray droplets which were produced by a spinning disc atomiser. Droplets collected on antennae, head, abdomen, legs and wings were sized and counted. The collection efficiency at wind-speeds ranging from 2 m/sec to 6 m/sec was calculated for the different body parts in the droplet size range 10–40, 40–60 and 60–80 μm. The calculated collection efficiency for the 10–40 μm size range was comparatively higher for all locust body parts.Item Elephants, Selective Logging and Forest Regeneration in the Kibale Forest, Uganda(Journal of Tropical Ecology, 1996) Struhsaker, Thomas T.; Lwanga, Jeremiah S.; Kasenene, John M.The Kibale Forest, western Uganda, is the only site where studies have compared the impact of elephants on rainforest regeneration in logged and unlogged control areas. Elephants used heavily logged areas more than lightly logged and unlogged areas. Forest gaps were used more by elephants than closed-canopy areas and large gaps more than small ones. Gaps were larger in logged than unlogged forest. There were lower densities of young trees (saplings and poles) and a higher incidence of elephant damage to them in heavily logged forest than in lightly logged and unlogged sites. Elephant use of an area and damage to young trees was inversely or unrelated to the density of young trees and directly related to the density of herbaceous tangle. Heavy logging resulted in large areas of herbaceous tangle, which attracted elephants who suppressed forest regeneration by damaging young trees and perpetuating the herbaceous tangle. The tangle directly competed with regeneration of young trees while also attracting elephants and rodents (seed and seedling predators) and facilitating increased windthrow of trees. Selective browsing of young trees by elephants affected rates of regeneration, growth form and species composition. Rather than remove elephants, a more effective and humane approach to long-term management of logging is to reduce logging offtake and incidental damage caused by timber extraction.Item Interaction of Ht and Partial Resistance to Exserohilum turcicum in Maize(Plant disease, 1997) Lipps, P. E.; Pratt, R. C.; Hakiza, J. J.Components of northern leaf blight resistance in maize due to race-specific resistance controlled by the Ht gene, partial resistance derived from inbred H99, and a combination of the two kinds of resistance, were studied subsequent to inoculation with Exserohilum turcicum race O. Lesion types, number of lesions (lesion number), percent leaf area affected (severity), and area under the disease progress curve (AUDPC) based on lesion number and severity were assessed in field studies conducted at two locations in Uganda and one location in Ohio in 1993. Lesion types observed were consistent for genotypes across locations. In general, significant differences among genotypes for data based on lesion number and severity were consistent for AUDPC based on lesion number and severity, respectively, at all locations. In Ohio, both Ht and partial resistance were effective in limiting disease development. In Uganda, susceptible inbreds (A619, A635, and B73) generally had higher severity than genotypes with partial resistance (H99, Mo17, and Babungo 3). However, there was a difference in response among genotypes depending on disease intensity at each location. Ht resistance and moderate partial resistance did not greatly affect lesion number at the higher disease intensity location, compared with the susceptible inbreds, but at the lower disease intensity location genotypes with partial resistance had fewer lesions than susceptible inbreds or the Ht conversions of the susceptible inbreds. At both plot locations, genotypes with partial resistance had lower severity than the susceptible inbreds or Ht conversions of the susceptible inbreds. Hybrids derived from crossing H99 with genotypes with moderate levels of partial resistance (Mo17 and Babungo 3) did not have significantly lower lesion numbers than hybrids of susceptible inbreds crossed with H99, but severity was significantly lower on these hybrids at the high disease intensity location. Results indicate that the level of partial resistance in H99 would be as effective in controlling northern leaf blight as using Ht resistance, or a combination of Ht resistance and moderate levels of partial resistance as found in Mo17.Item Changes in leaf lamina shape and size during banana shoot development(Journal of Applied Biosciences, 1997) Blomme, Guy; Turyagyenda, Laban Frank; Soka, Geofrey; Swennen, RonyBananas and plantains are grown as perennial crops, producing consecutive generations from suckers, which develop on the main plant. Sucker development consists of distinct physiological stages: peeper (small sucker appearing just above the ground and bearing scale leaves only), sword sucker (large sucker with lanceolate type leaves) and maiden sucker (large non-fruiting sucker with foliage leaves). Peepers, sword suckers and maiden suckers represent a distinct physiological stage in sucker growth with distinct morphological features, the most important being the leaf lamina size. The aim of this study was to assess changes in leaf lamina shape during the growth of lateral shoots and to determine how fast suckers from different genotypes develop broad leaves to manufacture their own food through photosynthesis, and thus reducing their dependency on the parent for nutrients. This can be achieved by determining how fast the sucker leaf length: width ratio halves (i.e. the RL50 value).Item Mangabey (Cercocebus albigena) Ranging Patterns in Relation to Fruit Availability and the Risk of Parasite Infection in Kibale National Park, Uganda(American Journal of Primatology, 1997) Olupot, William; Chapman, Colin A.; Waser, Peter M.; Basuta, Gilbert IsabiryeTwo opposing hypotheses concerning determinants of mangabey (Cercocebus albigena) ranging patterns have been advocated. One hypothesis suggests that ranging patterns of mangabeys are largely a response to fruit availability, while the other hypothesis advocates that concerns of fruit availability are supplemented or overridden by concerns of fecal contamination and that the risk of parasite infection, especially during dry weather, determines their pattern of range use. In this 9 month study of mangabeys in the Kanyawara study area of Kibale National Park, mangabeys moved longer distances during the wet season than during the dry season. There were no seasonal differences in group spread, number of 50 by 50 m quadrats used, or in quadrat overlap between sequential sample periods. Intensity of quadrat use was closely related to the number of fruiting trees/lianas in the quadrats, irrespective of season. These findings are consistent with the hypothesis that fruit availability is a main factor influencing mangabey ranging patterns. The results are not consistent with the hypothesis that mangabey ranging patterns largely reflect differential seasonal risk of parasite infection.Item Complementarity and the Use of Indicator Groups for Reserve Selection in Uganda(Nature, 1998) Howard, Peter C.; Kigenyi, Fred W.; Baltzer, Michael; Lwanga, Jeremiah S.; Matthews, Roger A.; Balmford, AndrewA major obstacle to conserving tropical biodiversity is the lack of information as to where efforts should be concentrated. One potential solution is to focus on readily assessed indicator groups, whose distribution predicts the overall importance of the biodiversity of candidate areas. Here we test this idea, using the most extensive data set on patterns of diversity assembled so far for any part of the tropics. As in studies of temperate regions we found little spatial congruence in the species richness of woody plants, large moths, butterflies, birds and small mammals across 50 Ugandan forests. Despite this lack of congruence, sets of priority forests selected using data on single taxa only often captured species richness in other groups with the same efficiency as using information on all taxa at once. This is because efficient conservation networks incorporate not only species-rich sites, but also those whose biotas best complement those of other areas. In Uganda, different taxa exhibit similar biogeography, so priority forests for one taxon collectively represent the important forest types for other taxa as well. Our results highlight the need, when evaluating potential indicators for reserve selection, to consider cross-taxon congruence in complementarity as well as species richness.Item Assessing Fern Diversity: relative species richness and its environmental correlates in Uganda(Biodiversity & Conservation, 1998) Lwanga, Jeremiah S.; Balmford, Andrew; Badaza, RoseTechniques for the rapid quantification of tropical biodiversity are of critical importance in deciding where to invest scarce conservation resources. Here we describe a simple survey method for assessing species-level richness of a poorly known plant group, the pteridophytes. We then illustrate the use of a powerful, rarefaction- based technique of controlling for inevitable differences in sampling effort to calculate the relative species richness of our study sites. Lastly, we explore how closely observed patterns of relative species richness of Ugandan forests are correlated with a suite of simple environmental variables. We find that fully 75% of the variance in our estimate of fern diversity can be predicted from just two measures: soil fertility (scored as C/N ratio, itself related to rainfall); and distance from the nearest putative Pleistocene refugium.Item Increasing Conversion in Membrane Filtration Systems using a Desupersaturation Unit to Prevent Scaling(Desalination, 1998) Bremere, Ingrida; Kennedy, Maria D.; Amayo, JohnA desupersaturation unit (DU), placed between the stages of either RO or NF systems is aimed at reducing the degree of supersaturation in the concentrate stream thus preventing membrane scaling in the last stage of a membrane filtration system while allowing conversion to be maximized up to design limits (>90%). Barium sulfate desupersaturation in an up-flow fixed bed reactor was demonstrated for ca. 200 h (Concentrate A). However, barium removal in the DU was shown to be source dependent and early break-through of the DU occurred with Concentrate B after ca. 30 h. Calculations showed that barium sulfate deposition in the DU was affected by natural organic matter (NOM). Blocking of seed crystal surface by rapid adsorption of certain NOM fractions hindered crystal growth and was believed to be the main reason for break-through in the DU. Recycling of these naturally occurring organic molecules as “natural antiscalants” to maximize the conversion of RO (NF) systems may be possible if they can be isolated and characterized.Item Pests and diseases on cowpea in Uganda: Experiences from a diagnostic survey(African Crop Science Journal, 1999) Adipala, E.; Omongo, C.A.; Sabiti, A.; Obuo, J.E.; Edema, R.; Bua, B.; Atyang, A.; Nsubuga, E.N.; Ogenga-latigo, M.W.A diagnostic survey (DS) using a questionnaire covering 525 farm households was conducted in 1993/94 to determine the status of cowpea (Vigna unguiculata L. Walp) and its production constraints in Uganda. Subsequent on-farm assessments were made during the two rainy seasons of 1994 to verify and quantify the survey information. Additionally, on-station trials were conducted to address issues arising from the information. Insect pests, low plant population densities, poor weed management and labour bottlenecks are the most important constraints to cowpea production in Uganda. Insect pest damage, particularly by bruchids, is most important. Research to develop integrated pest management (IPM) strategies based on the finding of this study are in progress.Item Population dynamics of ticks on indigenous cattle in a pastoral dry to semi-arid rangeland zone of Uganda(Experimental & applied acarology, 1999) Okello-Onena, J.; Tukahirwa, E. M.; Perry, B. D.; Rowlands, G. J.; Nagda, S. M.; Musisi, G.; Boded, E.; Heinonend, R.; Mwayia, W.; Opuda-Asibo, J.Studies on seasonality and population dynamics of ticks on indigenous cattle and their crosses (calves) were carried out in Buruli Ranching Scheme, Nabiswera, Luwero district of Uganda on three treatment groups of animals: group 1 (twice a week dipping), group 2 (once a month dipping) and group 3 (no tick control). During this study, four major species of ticks of economic importance were recorded in decreasing order of abundance: Rhipicephalus appendiculatus, Rhipicephalus evertsi evertsi, Amblyomma variegatum and Boophilus decoloratus. Of these ticks, a seasonal pattern of activity was only observed in R. appendiculatus ticks, with peak activities occurring during rainy seasons. Greater numbers of ticks were recorded on cows than calves in the three treatment groups, with the exception of A. variegatum where the reverse occurred. The mean numbers of ticks per animal were highly significantly different (p ,0.01) when group 1 animals were compared with group 2 and 3 animals. However, no significant differences (p .0.05) were observed in mean tick numbers between group 2 and 3 animals. Highly significant differences (p ,0.01) were observed in mean tick numbers on cows and calves (more than 12 months old) in different calving seasons. The state of lactation only affected tick counts on cows in group 1; significantly more ticks (p ,0.01) were observed in lactating than non- lactating cows. Furthermore, significantly greater (p ,0.05) numbers of ticks (with the exception of B. decoloratus) were recorded during the second year of study (March 1992–May 1993) than the first year (January 1991–February 1992), despite lower rainfall during the former period.Item Spatial Distribution of Nematode Population Densities and Nematode Damage in Roots of Three Banana Cultivars in Uganda(Nematropica, 2000) Talwana, H. A. L.; Speijer, P. R.; Waele, D. DeThe spatial distribution of nematode populations and damage in roots of Nabusa ( Musa AAAgroup ‘Matooke’), Pisang Awak ( Musa ABB) and Sukali Ndizi ( Musa AB) three banana cultivars widely grown in Uganda, was investigated at three locations, each with a distinctive nematode population and composition. At Namulonge, central Uganda, where Radopholus similis was the dominant nematode species, and at Ntungamo, southwestern Uganda, where Pratylenchus goodeyi was the dominant species, suckers were removed from established mats and assessed for nematode reproduction and damage. At Namulonge, Ntungamo, and Mbarara, southwestern Uganda, where R. similis and P . goodeyi coexist, suckers removed three months after planting were assessed for nematode reproduction and damage. Nematode population density distribution along the primary roots was observed to be random for both plant types of the three cultivars at all locations. An exception was recorded for three-month-old sucker-derived plants of all three cultivars at Mbarara, where higher P . goodeyi densities were recorded closer to the corm. Nematode densities in primary roots, secondary roots, and root tips were generally not significantly different for both plant types of a single cultivar except for three month old sucker-derived Pisang Awak plants at Ntungamo where higher Meloidogyne spp. densities were observed in the root tips. Consistently, nematode damage (root necrosis) was higher ( P < 0.05) close to the corm than further along the primary roots, regardless of cultivar and location.Item The Effect of Oral Administration of Polyethylene Glycol on Faecal Helminth Egg Counts in Pregnant Goats Grazed on Browse Containing Condensed Tannins(Tropical Animal Health and Production, 2000) Kabasa, J. D.; Opuda-Asibo, J.; Ter Meulen, U.Thirty yearling F1 Anglo-Nubian 6 Mubende goats, averaging 21+0.45 kg, kept on free-range feeding in the Ankole range land, Uganda, were screened for health and nutritional status, effectively treated against helminth parasites, mated, and randomly divided into two equal groups during a 3-month preparatory phase. During the 6 months that followed, the goats in one group received a daily oral dose (50 g/goat) of poly(ethylene glycol) (PEG), while the other group acted as the control (no PEG). The goats were monitored for faecal nematode egg counts and body weight gains, along with the quality of their diet,nematode contamination of the pasture, and the prevailing climatic factors in area.Goats treated with PEG had significantly (p50.05)higher faecal helminth egg loads.Theme Nematode Eggs per gram of faeces (epg) of the PEG group (290 epg) was more than double that of the control group (129 epg). All the PEG-treated goats exhibited moderate to severe infections at the end of the experiment. The gain in body weight during gestation was lower (p50.05) in the PEG group (70.4 g per goat per day) than in the controlgroup (91.8 g per goat per day).The PEG group lost 2.3 g per goat per day in the fifth month. PEG deactivates condensed tannins, and it was concluded that condensed tannins play a significant role in reducing the negative effects of gastroin test in al helminth burdens in the natural free-range feeding system of the Ankole range land in Uganda. Selective feeding on such range lands might expose goats to optimal concentrations of dietary condensed tannins with resultant bene¢cial e¡ects.Item Regeneration of an afromontane forest Following agricultural encroachment in Southwestern Uganda(Israel Journal Of Plant Sciences, 2000) Lejju, Julius Bunny; Oryem-Origa, Hannington; Kasenene, John M.A study of the regeneration of an Afromontane forest was carried out in Mgahinga Gorilla National Park (MGNP), southwestern Uganda, following agricultural encroachment in the last 50 years. The landscape was changed by terracing and removing the indigenous vegetation and replacing it with exotic tree species. This study also examined the soil nutrient status of the formerly encroached area in the park. Species richness of indigenous trees was high in the formerly cultivated area. Twenty-six indigenous species were found in the formerly cultivated area, compared with 20 species in the natural forest and 12 species of indigenous trees found under exotic woodlots. There was a significant difference in species richness and density in the three habitat types. The natural forest supported the highest stem density (75%), and the lowest stem density (4%) was recorded under exotic woodlots. Seedlings (<2 cm diameter at breast height) accounted for the majority of juveniles in the three habitats. The natural forest had the highest density (24,625 seedlings/ha), and exotic woodlots supported the lowest stem density (1,350 seedlings/ha).Item Comparison of damage levels caused by Radopholus similis and Helicotylenchus multicinctus on bananas in Uganda(Annals of Applied Biology, 2000) Barekye, A.; Kashaija, N.; Tushemereirwe, W. K.; Adipala, E.Field surveys were done in 1997 and 1998 in Masaka district, Uganda, an area which is experiencing a decline in banana production, to assess level of damage caused by nematodes Radopholus similis and Helicotylenchus multicinctus at farm level. Ten farms within a radius of 2 km were selected and nematode damage assessed. The major nematodes encountered were Pratylenchus goodeyi, R. similis and H. multicinctus. P. goodeyi and H. multicinctus were more abundant than R. similis but R. similis had a stronger and significant correlation with root damage. A subsequent pot trial examined pathogenicities of R. similis and H. multicinctus in pure and mixed cultures on tissue cultured-banana plantlets. R. similis alone and in mixed population reduced root fresh weight significantly, and the percentage of root necrosis ranged between 22.8-41.6% and 18.3-45.5% for March 1998 and March 1999 trials, respectively. The difference in damage caused by R. similis alone and in mixed population was not statistically significant, and was higher than the damage caused by H. multicinctus alone. There were no significant differences in pathogenicity among the R. similis isolates from different parts of Uganda.Item Primate Community Dynamics in Old Growth Forest over 23.5 Years at Ngogo, Kibale National Park, Uganda: Implications for Conservation and Census Methods(International Journal of Primatology, 2000) Mitani, John C.; Struhsaker, Thomas T.; Lwanga, Jeremiah S.Few data exist regarding long-term changes in primate populations in old-growth, tropical forests. In the absence of this information, it is unclear how to assess population trends efficiently and economically. We addressed these problems by conducting line-transect censuses 23.5 years apart at the Ngogo study area in Kibale National Park, Uganda. We conducted additional censuses over short time intervals to determine the degree to which the temporal distribution of censuses affected estimates of primate numbers. Results indicate that two species, blue monkeys and red colobus, may have experienced significant reductions over the past 23.5 years at Ngogo. In contrast, five other species, baboons, black-and-white colobus, chimpanzees, mangabeys, and red-tailed guenons, have not changed in relative abundance. Additional findings indicate that different observers may vary significantly in their estimates of sighting distances of animals during censuses, thus rendering the use of measures of absolute densities problematic. Moreover, censuses conducted over short periods produce biased estimates of primate numbers. These results provide guidelines for the use of line-transect censuses and underscore the importance of protecting large blocks of forests for primate conservation.