Heartwater. An overview of the clinical signs, susceptibility and differential diagnoses of the disease in domestic ruminants

Heartwater is a frequently fatal tick-borne disease of ruminants caused by Cowdria ruminantium. In domestic ruminants the incubation period varies considerably and depends on the route of infection, virulence of the isolate and amount of infective material administered. Adult cattle of all breeds appear to be equally susceptible to heartwater. It is generally accepted that calves up to the age of 3 weeks have a high degree of natural resistance which is not related to the immune status of the dam. Nervous symptoms are frequently seen in animals affected by the peracute and acute forms of heartwater and can easily be confused with similar signs caused by infectious conditions, toxic plants, acaricide and heavy metal poisonings.     

Water relations and keeping-quality of cut Gerbera flowers. V. Role of endogenous cytokinins

The objective of the present work was to investigate if differences in internal water relations, due to differences in membrane permeability, between Gerbera petals of inflorescences ageing in a vase and on the plant could be ascribed to differences in cytokinin activities. Moreover, cytokinin activities in petal-extracts of 3 cultivars, differing in their keeping-quality, were compared.Cytokinin activities (“free” and “bound”) in petals decreased during the first 6 days of the experiment (both in the vase and on the plant). On Day 8, a very high activity was found in almost all the R_f-fractions of the chromatogram. After Day 8, the activity decreased again. For young inflorescences, developing on the plant, a peak level was reached for “free” cytokinins at a very early bud stage and for “bound” cytokinins when the petals were just fully expanded. There were no correlations between petal-cytokinin activities at day of harvest of 3 Gerbera cultivars and their keeping-quality.It is concluded that changes in membrane permeability, which occur during ageing of petals of cut Gerbera inflorescences, are not triggered by changes in cytokinin activities.     

Clinical and pathological observations on spontaneous bovine respiratory syncytial virus infections in calves

A clinical, pathological and microbiological study was made of acute spontaneous bovine respiratory syncytial virus infection in calves. Characteristic features were atelectatic areas, which had an exudative and, or, necrotising bronchiolitis with syncytial giant cells in the epithelial lining and in the lumina of these bronchioles. Restricted to these areas both bronchiolar and alveolar immunofluorescence for bovine respiratory syncytial virus were seen. Complications were severe interstitial oedema, interstitial emphysema and a catarrhal or fibrinous pneumonia due to secondary bacterial invasion.     

Development and reproduction of Adalia bipunctata (Coleoptera: Coccinellidae) on eggs of Ephestia kuehniella (Lepidoptera: Phycitidae) and pollen

Due to growing criticism over the use of non-indigenous coccinellids, the two-spot ladybird, Adalia bipunctata (L.), has enjoyed increasing attention for aphid biocontrol in Europe. In the current study, eggs of the Mediterranean flour moth, Ephestia kuehniella Zeller, whether or not supplemented with bee pollen, were evaluated as a factitious food for larvae and adults of A. bipunctata. The predator showed slower larval development and lower survival when reared on live pea aphids, Acyrthosiphon pisum (Harris), than on E. kuehniella eggs. Survival on gamma-irradiated eggs of E. kuehniella was superior to that on frozen flour moth eggs, but other developmental characteristics were similar. Adults of A. bipunctata reared on Ac. pisum were only half as fecund as those offered irradiated or frozen E. kuehniella eggs, but egg hatch was markedly better on live aphids than on flour moth eggs (61 versus 20-27%, respectively). However, when a diet of flour moth eggs was supplemented with frozen moist bee pollen, egg hatch of A. bipunctata was equally as good as on live aphids. Supplementing flour moth eggs with dry pollen did not yield satisfactory results. Only 10% of larvae reached adulthood on moist bee pollen alone and resulting adults weighed less than half as much as those obtained on flour moth eggs. Our findings indicate that A. bipunctata is able to compensate for a suboptimal diet of animal prey by supplementary feeding on flower pollen. It is concluded that pollinivory may be a crucial trait for both the rearing of this natural enemy and its use in biological control programmes.     

An apparatus for the restraint of sheep during infestation with schistosomes.

With this adjustable apparatus sheep aged from five months to five years and varying in mass from 16-95 kg could be restrained effectively. Cercarial suspension was split by only 2/44 sheep during infestation with Schistosoma mattheei. Using a battery of seven cages, it was possible to infest 23 sheep, each for 30 minutes, in one day. No cercariae were more than 4-1/2 hours old at the end of exposure.     

The immune system of cyprinid fish. Oxytetracycline and the regulation of humoral immunity in carp (Cyprinus carpio)

The antibiotic oxytetracycline (oxyTC) was administered either by mixing with food or by intraperitoneal injections. In oxyTC treated animals decreased serum immunoglobulin levels were found. The primary anti-sheep red blood cell (SRBC) response was measured by enumerating plaque forming cells (PFC). It was observed that the PFC response was depressed by 80–95% in oxyTC treated animals. When an anti-SRBC serum was injected together with SRBC the immunosuppressive effect of oxyTC was absent. A secondary anti-SRBC response was not inhibited by oxyTC. On base of the results a model for antigen presentation and the interaction between macrophages, T- and B-like cells during primary and secondary responses in fish is proposed. In primary responses cellular interaction is needed to develop a proper immune response whereas after a high antigen dose challenge SRBC might behave as a T-independent antigen.     

Feline histiocytic colitis. A case report with electron microscopy.

A 5-year-old cat with clinical colitis had histiocytic inflammation of colonic mucosa. Light and electron microscopy demonstrated bacilli, 0.7 x 3.0 micrometers, in various stages of degradation within macrophage cytoplasm. The disease is similar to histiocytic granulomatous bowel disease of other species. The cat responded to long-term treatment with antibiotics.