Simulation of herbicide persistence in soil .III. Propyzamide in different soil types

The effects of soil temperature and soil moisture content on the rate of degradation of propyzamide in five soils were examined under controlled laboratory conditions. Half-lives in soils incubated at field capacity varied from 23 to 42 days at 25°C and from 63 to 112 days at 15°C. The variation in half-life at 25°C and 50% of field capacity was from 56 to 94 days. When the laboratory data were used in conjunction with the relevant meteorological records and soil properties in a computer simulation program, predicted degradation curves for propyzamide in four of the soils in micro-plots were in close agreement with those observed. Use of the program to predict residues of propyzamide in the fifth soil at crop maturity in a series of field experiments concerned with continuity of lettuce production gave values fairly close to those observed when appropriate corrections were made for initial recoveries.     

Coinfection by Cryptosporidium parvum and porcine circovirus type 2 in weaned pigs

Routine histopathological diagnosis of one representative 3-month-old pig from a group suffering from diarrhoea revealed a massive degree of parasitation by Cryptosporidium parvum, with a concomitant infection by porcine circovirus type 2 (PCV2), that was confirmed by immunohistochemical procedures. The areas of intestine where parasites were more numerous presented abundant PCV2 infected cells in mucosa and submucosa. The concurrence of C. parvum, a rare primary intestinal pathogen in post-weaning and growing pigs, and PCV2 infections suggest an increased susceptibility as a result of an immunosuppression state.     

Field efficacy of ivermectin plus praziquantel oral paste against naturally acquired gastrointestinal nematodes and cestodes of horses in North America and Europe

The efficacy of an oral formulation of ivermectin plus praziquantel in the reduction of nematode and cestode egg counts in horses was assessed in 273 horses under field conditions at 15 sites in North America (n = 6) and Europe (n = 9). Horses were confirmed by fecal examination to have natural infections of strongyles (100%) and tapeworms (76%). Replicates of four horses were formed at each site, and in each replicate three animals received ivermectin (0.2 mg/kg body weight) plus praziquantel (1 mg/kg body weight) oral paste and one animal remained untreated or received vehicle paste. Fecal samples were collected for fecal nematode and cestode egg counting before and 7, 8, 9, 14, 15, and 16 days after treatment. Horses treated with ivermectin plus praziquantel oral paste had significantly (P <.01) lower posttreatment strongylid and cestode egg counts (reductions of 98% or more) than controls. Combined site analyses revealed that 95% or 96% of the horses positive for cestode eggs before treatment that were treated with ivermectin plus praziquantel were negative for cestode eggs at each posttreatment fecal examination. No adverse reactions attributable to ivermectin plus praziquantel oral paste treatments were observed. The results of the studies demonstrated that ivermectin plus praziquantel paste was highly effective in reducing egg shedding by gastrointestinal nematodes and cestodes, and no adverse reactions were observed in horses treated under field conditions.     

Characterization of an avianpox virus isolated from an Andean condor (Vultur gryphus)

A novel pox virus, condorpox virus (CPV) isolated from the spleen of an Andean condor (Vultur gryphus) by inoculation of chorioallantoic membranes (CAM) of specific pathogen free (SPF) chicken embryos was compared biologically, antigenically and genetically with fowlpox virus (FPV), the type species of the genus Avipoxvirus. Susceptible chickens inoculated with CPV developed only mild localized lesions but were not protected against subsequent challenge with FPV. Based on Western blotting, in addition to the presence of cross-reacting antigens, distinct differences in antigenic profiles of CPV and FPV were observed. Sequence analysis of a 4.5 kb HindIII fragment of CPV genomic DNA revealed the presence of eight co-linear genes corresponding to FPV open reading frame (ORF)193-198, 201 and 203. Interestingly, reticuloendotheliosis virus (REV) sequences present in the genome of all FPV were absent in CPV. Although, the results of a phylogenic analysis suggested that CPV is a member of the genus Avipoxvirus, its unique antigenic, biologic and genetic characteristics distinguish it from FPV to be considered as a new member of this genus.     

Survival of Ornithobacterium rhinotracheale in sterilized poultry litter

Ornithobacterium rhinotracheale (ORT) has been associated with respiratory disease, increased mortality, retarded growth, and decreased egg production in chickens and turkeys. Surveillance of exposure to ORT infection in the field has shown that prevalence of the infection is higher during winter months. The ability of ORT to remain viable in the poultry litter was studied at different temperatures over time. Presterilized poultry litter was inoculated with 10(11) colony-forming units of ORT and kept at -12 C, 4 C, 22 C, 37 C, and 42 C. Reisolation and titration of ORT from litter was attempted at intervals. Results indicate that ORT survived for 1 day at 37 C, 6 days at 22 C, 40 days at 4 C, and at least 150 days at -12 C. ORT did not survive 24 hr at 42 C. The survival of ORT at lower temperatures may be associated with the higher incidence of ORT infection in poultry during winter months.     

Outer membrane proteins for serologic detection of Ornithobacterium rhinotracheale infection in turkeys

Ornithobacterium rhinotracheale (ORT) is a bacterium responsible for a respiratory disease in turkeys and chickens and has been identified as one of the emerging respiratory bacterial pathogens. The clinical signs and lesions caused by ORT are very similar to those caused by other respiratory infectious agents; therefore, an accurate diagnostic test is necessary to identify the infection. In this study, we have investigated the use of outer membrane proteins of ORT in an indirect enzyme-linked immunosorbent assay (ELISA) to detect the exposure to ORT infection. Outer membrane proteins of ORT were extracted and used as an antigen in ELISA to detect infection in turkeys exposed to different serotypes of ORT. The ELISA results were compared with the conventional serum plate agglutination test. The agglutination test detected specific antibodies for ORT in 65% of experimentally infected turkeys during the first 2 wk of infection. The ELISA detected up to 100% of infected birds for 8 wk postinfection. The results suggest that ELISA is able to detect the exposure to ORT in later stages of the infection and this assay can be used in serologic surveillance of ORT infection for poultry in the field.     

Mucopolysaccharidosis IIIA (Sanfilippo syndrome) in a New Zealand Huntaway dog with ataxia

AIM: To investigate the nature of a progressive ataxia in a New Zealand Huntaway dog. METHODS: The affected dog was examined clinically before being humanely killed and necropsied. Selected tissues were submitted to light and electron microscopy and to biochemical analyses. RESULTS: The histological lesions were interpreted as indicative of one of the forms of mucopolysaccharidosis type-III (MPS-III), a lysosomal storage disease. Biochemically there was a deficiency of heparan sulphamidase. All the heparan sulphate chains had non-reducing-end glucosamine-N-sulphate residues. CONCLUSION: The disease is MPS-IIIA (Sanfilippo syndrome). An autosomal recessive mode of inheritance can be provisionally assumed from the nature of this disease in other species.     

Splenic mast cell tumour and mastocytaemia in a cat: case study and literature review

CASE: An 11-year-old female domestic shorthaired cat presenting with clinical signs of depression, anorexia, weight loss, fever, anaemia and a mid-abdominal mass was referred for abdominal ultrasound examination. CLINICAL FINDINGS: Ultrasonography of the abdomen identified a markedly enlarged spleen. Ultrasound-guided fine-needle aspiration biopsy of the spleen revealed a uniform population of mast cells, 11% of which were observed to have phagocytosed erythrocytes. It is speculated that this may have been a contributing factor in the development of anaemia in this case. Mast cells were detected in a peripheral-blood smear and a diagnosis of systemic mastocytosis (splenic mast cell tumour together with mastocytaemia) was made. This diagnosis was subsequently confirmed by histopathology of the spleen. CONCLUSION: Splenectomy and treatment with corticosteroids appears to have resulted in remission of clinical signs and anaemia. A reduction in the concentration of mast cells in the peripheral blood had not occurred 6 weeks postsplenectomy, but was evident by 10 months post-splenectomy.