Evaluation of trypanosomiasis control alternatives using an epidemiologic simulation model

The effect of various disease-vector control alternatives on the prevalence of trypanosomiasis in southwest Ethiopia was examined with the aid of an epidemiologic model. The alternatives considered included vegetation clearing by manual labor, game elimination, insecticidal spraying from airplanes coupled with settlement, use of sterile male Glossina, avoidance of tsetse infested areas, increasing the resistance of the cattle population, therapy, and combinations of the above methods. First, the currently estimated endemic prevalence of trypanosomiasis (27.3%) in the simulated area of Ethiopia was established and maintained over a 10 year period. Then, various control alternatives were introduced and the simulation was run for an additional 10 years to observe the effect of these control alternatives on the prevalence. The combined use of vegetation clearing, insecticides, therapy, and settlement (or resettlement) was the most effective and feasible method of trypanosomiasis control for the simulated situation.     

La musculature peaucière de la tête chez un jeune Lamantin du Sénégal (Trichechus senegalensis Link 1795; Mammifère, Sirénien)

The cutaneous musculature of a young Manatee (Trichechus senegalensis Link, 1795; Mammals, Sirenia) Adaptation of the manatee to marine life and to a plant diet has markedly changed the cutaneous musculature of the head. Like whales the manatee lacks pelvic limbs and has an extensive cutaneous muscle of the trunk (m. panniculus carnosus) which also covers part of the head corresponding here to the m. platysma myoides of the other mammals. The muscle extends into the lateral parts of the overhanging upper lip, is very thick here and represents the m. zygomaticolabialis. As in whales whose skull is covered with thick skin, the occipitofrontal musculature has disappeared. The same is true for the musculature of the ear; only a connection between the m. platysma and the external acoustic meatus (pars auricularis) remains. The large upper lip with its pendulous lateral parts is thickened in addition by all the derivatives of the deep cervical sphincter (m. nasolabialis, m. maxillolabialis) and its very thick oral part. The oral part froms a ventral sling rostral to the fibrous plate situated under the chin, which, in conjunction with the mentalis and the mental part of the buccinatorius, seems to play a role in the prehension of plants in that it facilitates the grasp of the lateral part of the upper lip, The m. dilatator nasi together with the m. nasolabialis controls the opening and closing of the nostril similarly to what has been described for the hippopotamus.     

An evaluation of new growth retardants on Mid-Century Hybrid lilies

The new growth retardants piproctanyl bromide (Alden or Stemtrol), dikegulac-sodium (Atrinal), PP 528 (a phenyl tetrazole compound) and 2,3-dihydro-5,6-diphenyl-1,4-oxathiin (coded UBI-P293) were compared with the established compounds chlormequat chloride (Cycocel), ancymidol (A-Rest or Reducymol) and chlorphonium chloride (Phosfon), for their ability to dwarf Mid-Century Hybrid lily cultivars ‘Enchantment’ and ‘Joan Evans’. Single compost drenches were given 2–3 weeks after transferring plants to the glasshouse.Piproctanyl bromide at high concentrations (2000 mg a.i. per plant) produced some dwarfing, as did chlorphonium chloride (at 250 mg a.i. per plant). Chlormequat chloride produced a similar response at 1250 mg a.i. per plant, but on a concentration basis ancymidol was by far the most active compound (only 0.25–0.50 mg a.i. per plant was required). Plant and flower quality was generally good with these 3 chemicals.Dikegulac-sodium reduced stem length but prevented the development of flower buds and the plants senesced. PP 528 also restricted stem extension but plant quality was unsatisfactory; increasing concentrations led to smaller florets, weaker stems and drooping leaves. UBI-P293 produced as great a reduction in stem length as did ancymidol, and 100 mg a.i. per plant was as active as 500 mg. However, as the concentration was raised there was a decrease in floret size and number.     

Herbicides and grassland improvement

Under normal systems of grassland management, most sown swards become invaded by weed grasses. This ingress is usually associated with a depletion in the size and number of the sown species. Selective herbicides can be used to combat this grass invasion and the results of two experiments are presented to show how low-dose dalapon in mid-July can be used for this purpose. When the sown grasses are too severely depleted, some method of introducing seed is required. A new one-pass technique is now being developed for establishing grass and clover seed into existing swards. After sowing, ways of increasing the clover content are being studied, based on the use of grass-suppressing herbicides in late winter. In one experiment several-fold increases in clover growth were recorded 5 months after applying carbetamide (2.8 kg/ha) and propyzamide (0.8 kg/ha).     

Handheld computers in veterinary medical education: a view from human medical education

Handheld computers are widely used in clinical practice, and their use in both human medical education and veterinary medical education is increasing, especially, for the former, in activities involving point-of-care access. This article references the insights that can be obtained from the usage and activities that are gaining a strong foothold in human medical education. Handheld computer technology gives students access to a large and changing knowledge base for clinical practice, especially when they are geographically dispersed. Differences in use between education and practice largely relate to the importance clinicians place on patient information. Student use focuses on progress mapping and ready access to clinical reference material. Suggestions are made for future use in medical education.     

Transstadial and intrastadial experimental transmission of Ehrlichia canis by male Rhipicephalus sanguineus

The acquisition and transmission of rickettsial pathogens by different tick developmental stages has important epidemiological implications. The purpose of this study was to determine if male Rhipicephalus sanguineus can experimentally acquire and transmit Ehrlichia canis in the absence of female ticks. Two trials were performed where nymphal and male R. sanguineus were simultaneously acquisition fed on the same infected donor hosts, and transstadially or intrastadially exposed male ticks were fed on separate pathogen-free dogs as a test for transmission. A single-step p30-based PCR assay was used to test canine and tick hosts for E. canis infections before and after tick feeding. E. canis was detected after either intrastadial or transstadial passage in male ticks, the organism remained detectable in both tick groups after transmission feeding, and both tick groups transmitted the rickettsia to susceptible dogs. Infection of dogs via tick feeding resulted in milder clinical signs and lower antibody titers than intravenous inoculation of carrier blood, but further investigation is needed to understand the mechanisms responsible for this observation. These results demonstrate that male R. sanguineus can take multiple feedings, and that they can both acquire and transmit E. canis in the absence of female ticks. This tick development stage could be important in transmission of E. canis, and perhaps related pathogens, between vertebrate hosts under natural and experimental conditions.