Studies on bovine demodecosis in northern Nigeria

Summary The study reported in the present paper discusses the clinical and histological picture of bovine demodecosis and the morphology of Demodex mites as seen in four cows suffering from generalized demodecosis. There were no clinical signs of other skin affections. Changes in both the number and the appearance of visible skin lesions were seen and related to the level of nutrition and the exposure to sunshine of the cattle. Histological sections of some skin nodules showed the presence of mite colonies in the hair follicles. Only adults were seen in the sebaceous glands. Microscopical study of the morphology of the mites revealed the presence of two types of demodicids in the skin lesions and three types from epilated eyelashes. Morphological criteria are presented to aid in identification of species and of life stages.     

Pasteurella haemolytica infections in sheep

Summary Pasteurella haemolytica causes two distinct disease syndromes in sheep. P. haemolytica biotype A causes septicaemia in young lambs and pneumonia in all ages of sheep. Biotype T produces an acute systemic disease affecting principally the upper alimentary tract and lungs in young adult sheep. The bacteriology, epidemiology and clinical and necropsy findings of the two diseases are described and the current situation regarding their experimental reproduction and immunology is reviewed.     

Preliminary description of a potyvirus from Vallota speciosa

Apotyvirus, isolated fromVallota speciosa, is tentatively designatedVallota mosaic virus (VMV). VMV was easily transmissible in sap and could be transferred byMyzus persicae in a nonpersistent manner. Infection was symptomless inNicotiana clevelandii andSpinacia oleracea, whereasHyoscyamus niger, chenopodium quinoa, C. amaranticolor, Tetragonia expansa andGomphrena globosa reacted with local lesions. Dilution end-point was 10⁴–10⁵, thermal inactivation at c. 60°C and ageing in vitro 4–8 days. With the electron microscope elongate particles with a normal length of about 750 nm could be detected in crude sap. In ultrathin sections virus particles were observed in the cytoplasm, dispersed as well as aggregated. Pinwheel and laminate aggregated inclusions were present in sectioned leaf material. The inclusions observed in negatively stained crude sap preparations exhibited fine linear striations with a periodicity of 5.3 nm.     

Writing, dictating, and speaking letters

It is commonly assumed that dictation requires a long time to learn, but authors eventually dictate much faster than they write. Performance results now show that novice dictators can learn in a few hours to dictate with the speed and quality with which they write. However, they do not think they perform this well. Dictators with years of experience are from 0 to 25 percent faster than novices, depending upon the complexity of the letters. Planning time is about two-thirds of composition time, regardless of the method of composition.