Use of netting and whitewash spray to protect papaya plants against Nivun Haamir (NH)-dieback disease

A disease causing the decline of papaya (Carica papaya) plants was noticed in the Jordan Valley in 1982. The disease caused severe yellowing of the upper leaves and dieback of the apex. The disease was not transmissible mechanically and continued efforts to associate viruses and viroids have so far been unsuccessful. Epidemiological observations suggested that the disease is airborne and probably caused by a mollicute. In order to test this hypothesis, plots were covered by an insect-proof net and with white nets providing 15, 30 and 50% shade. The 30%, 50% and insect-proof nettings provided complete protection, and the 15% netting reduced disease incidence to <2%, compared with>37% in the uncovered control plot. Spraying plants at weekly intervals with a commercial whitewash solution was also found to be effective in reducing disease incidence. The advantages of using a range of netting field treatments as a simple means for obtaining information on the epidemiological nature of a new disease are described.     

Large granular lymphoma in an FIV-positive and FeLV-negative cat

The clinical course of a feline leukaemia virus (FeLV)-negative and feline immunodeficiency virus (FIV)-positive cat affected with a large granular lymphocyte lymphoma is presented. Cyto-logical examination showed neoplastic cells in the pleural effusion and in two abdominal masses. Bone marrow and peripheral blood were moderately involved and chemotherapy was used to control the tumour. Cytochemistry, immunohis-tochemistry and ultrastructural studies were applied to define the cellular lineage; cytochemistry suggested a T-cell lineage.     

Duck lymphocytes. VI. Requirement for phagocytic and adherent cells in lymphocyte transformation.

Preparations of duck (Anas platyrhynchos) spleen and blood lymphocytes depleted of cells capable of phagocytosing carbonyl iron gave lower transformation responses to the mitogens phytohaemagglutinin (PHA), concanavalin A (Con A), Bandeiraea simplicifolia seed lectin (BSS), wheat germ agglutinin (WGA), lentil lectin (LL) and phorbol ester (PMA) than intact cell preparations. When cell populations were fractionated on the basis of their adherence to plastic, it was found that the adherent cells were responsive to PHA, Con A, BSS, WGA and PMA, while the non-adherent cells responded to LL. These observations confirm the expected requirement for phagocytic accessory cells in the induction of in vitro mitogen-driven duck lymphocyte responses. The responses of plastic-adherent populations of cells to most mitogens are believed to reflect the generally close physical relationship between the adherent accessory cells and the lymphocytes, although it remains possible that duck monocytes respond to some of the mitogens employed. The data also suggest that LL stimulates a population of cells different to those responding to other mitogens.     

A comparison of the gland of Harder response and head-associated lymphoid tissue (HALT) morphology in chickens and turkeys.

The immunofunctional response of the gland of Harder (GH) was compared in chickens and turkeys using an in vivo assay previously developed for use in chickens. The GH were surgically removed (GHx) from leghorn chicks at 1 day of age and from poults at 2 days of age. Intact birds of each species served as controls. During the fourth week of age, both GH-intact and GHx chicks were exposed to killed Brucella abortus antigen by the ocular or intraperitoneal route. One week later, serum and tears were collected and assayed for antibodies to B. abortus. In addition, all birds were killed at the end of the trial period, and the heads were fixed and processed for histologic examination. Various components of the head-associated lymphoid tissue (HALT) including the GH, nasal glands, lacrimal glands, lacrimal ducts, eyelid conjunctiva, and nasal cavity mucosa/submucosa, were evaluated microscopically using a scoring system to estimate quantity and degree of development of immune tissue in those sites. Results of all analyses indicate that functional response and morphology of the HALT are comparable in turkeys and chickens.     

The effect of porcine somatotropin supplementation in pigs on the lipid profile of subcutaneous and intermuscular adipose tissue and longissimus muscle.

The effect of porcine somatotropin (pST) on the lipid profiles of adipose tissue and muscle was investigated. Sixteen crossbred barrows were injected daily with either 3 mg of pST or a placebo. After slaughter, total lipid and fatty acid composition of raw subcutaneous (SC) adipose and intermuscular (IM) adipose tissue and longissimus muscle were determined. The SC adipose tissue from pST-treated pigs had a 7.5% decrease in total lipid content; specific fatty acids 16:0, 18:0, and 18:1(n-9)c decreased most. The IM fat from pST-treated pigs had lower levels of 16:0 and 20:0. There was no effect of pST treatment on the lipid profile of the longissimus muscle. The data suggest that pST treatment produces small but significant changes in the saturated fatty acid content of adipose tissue in pigs.     

Porcine urogenital disease.

Porcine urogenital disease is the result of an imbalance of the normal microflora of the urinary and reproductive tracts brought about by hormonal, environmental, and management-related stress factors. Production and economic losses can be substantial, and diagnosing and treating the problem can be frustrating. Through proper hygiene, facility design, and culling procedures, the severity of the problem can be minimized.     

Maturation of functional antibody affinity in animals immunised with synthetic foot-and-mouth disease virus.

A good correlation exists between specific neutralising antibody titre and protection against challenge with foot-and-mouth disease virus (FMDV) in infected or virus-vaccinated cattle, but not in the case of animals immunised with synthetic FMDV peptides. Therefore, mechanisms other than simple neutralisation are likely to be important in vivo. Antibody affinity may influence the protective capacity of sera from immunised animals and experiments were carried out to measure the functional affinity for synthetic FMDV peptide of sera from guinea pigs and cattle given various synthetic vaccines. In guinea pigs given a single dose of synthetic vaccine, antibody affinity increased with time after immunisation. In cattle, however, administration of a second dose of peptide 21 days after the first markedly retarded the process of affinity maturation. For guinea pig sera of equivalent neutralising activity, those of higher functional affinity had higher protective indices than those of lower functional affinity. Knowledge of the importance of antibody affinity in protection against FMD is important for an improved understanding of the mechanisms of protection and for the design of novel vaccines.     

Abattoir condemnation of pigs and its economic implications in Singapore

Losses due to mortality and rejection of carcases and viscera in a population of 2,959,607 pigs admitted for slaughter in Singapore abattoirs between 1984 and 1986 were studied. Mortality losses were 2822 pigs (9.5 per 10,000 admissions) while 3039 whole carcases (10.3 per 10,000 admissions) were condemned at post-mortem examination. The main reason for rejection of carcases was pyaemia (30.3%). Kidneys and livers were the two main organs of economic value rejected. Rejection of kidneys was primarily due to nephritis (54.8%) while liver condemnation was mainly due to cirrhosis (38.6%). The financial loss from abattoir rejection was S$5.27 millions or S$1.78 per pig admitted. The value of abattoir condemnation data as a tool in preventive medicine is discussed.     

Serum amyloid A protein (SAA) in horses: objective measurement of the acute phase response

A sensitive and precise immunoassay for equine serum amyloid A protein (SAA) was established and used to determine, for the first time, the circulating concentration of this protein in health and disease. As in other species, equine SAA was present only at trace levels in healthy animals but behaved as an extremely sensitive and rapidly responding acute phase reactant following most forms of tissue injury, infection and inflammation, objectively reflecting the extent and activity of disease. Measurements of SAA should make a significant contribution to diagnosis and management of viral and bacterial infection in horses, and routine serial assays could provide an objective criterion for monitoring prospectively the general health of horses in training and racing.