Identification and Partial Characterisation of <Emphasis Type="Italic">Lettuce big-vein associated virus</Emphasis> and <Emphasis Type="Italic">Mirafiori lettuce big-vein virus</Emphasis> in Common Weeds Found Amongst Spanish Lettuce Crops and their Role in Lettuce Big-vein Disease Transmission

The potential role of 10 frequently occurring weed species found amongst Spanish lettuce crops as host plants for the two viruses associated with the lettuce big-vein disease, Lettuce big-vein associated virus (LBVaV) and Mirafiori lettuce big-vein virus (MLBVV), was studied. The results showed that both viruses can infect naturally growing Sonchus oleraceus (common sowthistle) plants, the unique susceptible species detected among the analysed weeds. The sequences of the coat protein (CP) genes of the LBVaV and MLBVV isolates recovered from S. oleraceus plants were determined. Phylogenetic studies revealed a very close relationship between the CP sequences from these weed isolates and those from Spanish lettuce. Moreover, we showed that S. oleraceus can act as a source of lettuce infection by means of Olpidium brassicae, the vector fungus of both viruses.     

Risk factors for canine echinococcosis in an endemic area of Peru

An epidemiological study was conducted in a highland rural community in Peru to determine risk factors for canine echinococcosis caused by Echinococcus granulosus. Dogs were diagnosed using a coproantigen enzyme-linked immunosorbent assay (ELISA). Dog owners were interviewed prior to stool collection and asked for attitudes, practices and beliefs likely to be associated with local patterns of E. granulosus transmission. Univariate and multivariate analysis were used to determine odds ratios (OR) and their 95% confidence intervals (CI). The main risk factors found to be significantly associated with canine echinococcosis by univariate analysis were dog age (3-25 months) (OR, 5.14; CI, 1.7-15.7), female sex (OR, 4.3; CI, 1.4-13.3) and having been fed hydatid infected offal (OR, 2.9; 95% CI, 1.0-8.6). There was complete lack of knowledge about echinococcosis transmission. In addition to periodic dog treatment, control programs need to emphasize education of the human population to increase knowledge of parasite transmission and to change human practices associated with high rates of infection.     

Epizootic cutaneous pythiosis in beef calves

Enzootic bovine granulomatosis (EBG) is a disease that affects beef calves in the flooded Savanna regions of Venezuela. Although Pythium insidiosum was originally the suspected etiologic agent, nothing was done to demonstrate its presence in the infected animals. The objective of this study was to investigate the etiologic agent causing cutaneous lesions in a group of 63 calves diagnosed with EBG. The collected samples were analyzed by histopathology, immunohistochemistry, serology, and mycological techniques. The clinical manifestations of BEG included ulcerated and swollen granulomatous lesions on the limbs of young calves. Histopathological studies revealed an eosinophilic inflammatory reaction with neutrophils, giant cells and branching hyphae with the Splendore-Hoeppli phenomenon. Immunofluorescence analysis identified the branching hyphae as elements of the fungal-like organism P. insidiosum. Wet mounts in 10% KOH revealed hyaline slender branching hyaline coenocytic hyphae, but cultures from those samples were negative. Anti-P. insidiosum immunoglobulins were also demonstrated in the collected sera of the affected bovines using latex agglutination, immunodiffusion, ELISA, and Western Blot. The histopathological, immunohistochemical, and serological tests showed for the first time that P. insidiosum could be involved in epizootic bovine pythiosis.     

Resistance to <Emphasis Type="Italic">Penicillium</Emphasis><Emphasis Type="Italic">hirsutum</Emphasis> Dierckx in garlic accessions

Among the factors affecting the quality and yield of garlic production, blue mold caused by -- Penicillium spp. -- is responsible for economical losses in many countries. Allicin, present in garlic bulbs, has been suggested as having antifungal activity against some Penicillium species. This study was conducted to evaluate the response of garlic accessions against Penicillium hirsutum infection and to compare this response with bulb allicin content. Twelve garlic accessions were inoculated with P. hirsutum, and assayed in greenhouse and growth chamber experiments. Plant growth parameters and the fungal production of conidia were evaluated. Significant differences were found among the accessions. Accessions Castaño and Morado were most resistant whereas AR-I-125 and Fuego were always severely affected by the disease. A low correlation was found (r = 0.17) between allicin content and tolerance, indicating that allicin is not the main factor involved in the resistance against P. hirsutum.     

Molecular analysis suggests that recent <Emphasis Type="Italic">Citrus tristeza virus</Emphasis> outbreaks in Italy were originated by at least two independent introductions

Citrus tristeza virus (CTV) is the causal agent of the most important virus disease of citrus. Numerous CTV isolates differing in biological and molecular characteristics have been reported worldwide. Recently, CTV was detected in Italy in several citrus crops from three separate areas: (1) Cassibile, province of Syracuse; (2) Massafra, province of Taranto; and (3) Belpasso, province of Catania. CTV isolates from Massafra and Cassibile were mild, whereas isolates from Belpasso induced severe symptoms. To study the genetic variation of CTV populations of these areas, 150 samples per area were examined by single strand conformation polymorphism (SSCP) and nucleotide sequence analysis of CTV gene p20. All isolates from the same area showed the same SSCP pattern whereas for each area a different SSCP pattern was obtained. The Massafra and the Cassibile isolates had a nucleotide identity higher than 99% with a mild isolate from Spain and about 92% with the Belpasso isolates, which were similar (identity higher than 99%) to severe isolates from California and Japan. These results suggest at least two independent introductions of CTV in Italy, probably by import of CTV-infected budwoods. Within each area, the virus population was homogeneous suggesting diffusion of CTV by aphid transmission. The GenBank accession numbers of the sequences reported in this paper are: AY262000, AY263360 and AY263361 corresponding to gene p20 of CTV isolates from Massafra, Cassibile and Belpasso (Italy), respectively.     

Neurophysiological activity and toxicity of pyrethroids derived by addition of methylene,sulfur or oxygen to the chrysanthemate 2-methyl-1-propenyl substituent

Conversion of chrysanthemates to their cyclopropane, episulfide, and epoxide derivatives by addition of methylene, sulfur, or oxygen, respectively, to the 2-methyl-1-propenyl double bond yields products generally of reduced toxicity but enhanced neurophysiological activity and photostability. The reduced toxicity is established with cis-cyphenothrin derivatives administered intracerebrally to mice and topically to house flies and with cis-phenothrin derivatives applied topically to American cockroaches and house flies, even in the presence of piperonyl butoxide for the house flies. In contrast, cyclopropane, episulfide, and epoxide derivatives of phenothrin are more potent than the parent compound in eliciting repetitive firing following stimulation of a cercal sensory nerve of the American cockroach in vitro. The individual 1′R and 1′S isomers of epoxides derived from (1R,cis,αS)cyphenothrin, (1R,cis)phenothrin, and (1R,trans)tetramethrin differ in potency by up to 20-fold for insecticidal activity, >30-fold for intracerebral toxicity to mice, and ～100,000-fold in the cercal sensory nerve assay. In each case the epoxide isomer of higher R_f is more potent than that of lower R_f when derived from a trans-chrysanthemate and vice versa from a cis-chrysanthemate.     

Use of distraction osteogenesis for the correction of deviated nasal septum and premaxilla in a horse

A 13-month-old female Andalusian was evaluated because of a congenital left deviation of the maxilla and nasal septum, which had resulted in a gross malocclusion of the maxillary incisor teeth. Surgical correction of a deviated nasal septum and premaxilla in a horse was first reported in 1978 and involved a pre-maxilla osteotomy and use of an autogenous rib graft, with a nasal septum osteotomy performed in a second surgery; to the authors' knowledge, no alternative surgical treatments have since been described. In this horse, a new surgical treatment by distraction osteogenesis without nasal septum osteotomy was attempted. After the procedure, the premaxilla and nasal septum deviations were corrected; however, an overjet lesion (rostral projection of maxillary arcade over the mandibular arcade) was evident, for which the owners declined treatment. Compared with previously recommended procedures, distraction osteogenesis appears to be a less invasive treatment for congenital facial deformities and may be considered an option in the treatment of congenital deviation of the nasal septum and premaxilla (wry nose), head scoliosis, brachygnathism, and prognathism in horses.     

Virulence-associated genes in Escherichia coli isolates from poultry with colibacillosis: correction

Several virulence genes of avian Escherichia coli were detected in 200 colibacillosis isolates from our region by PCR. However, the genes sfaDE and facA were not detected in that study. In this work we correct those data, showing by colony hybridization that sfaDE and facA are present in 40% and 30% of those isolates, respectively.