Molecular phylogenetic analysis of Onchocerca lupi and its Wolbachia endosymbiont

The morphology of Onchocerca lupi, responsible for canine ocular onchocercosis, is unique within the genus. Earlier analyses of the 5S ribosomal RNA gene spacer region sequence of the parasite and the 16S ribosomal RNA gene sequence of its Wolbachia endosymbiotic bacteria (Rickettsiales) supported the morphological and biological arguments that O. lupi is a distinct species. However, the exact phylogenetic position of O. lupi and its endosymbiont could not be unambiguously determined. Herein we report analyses based on the mitochondrial cytochrome oxidase I (COI) gene of the filarial species and the Wolbachia surface protein (wsp) and the bacterial cell-cycle ftsZ genes of their wolbachiae. Our results indicate that O. lupi separated from other Onchocerca spp. early in evolution. This is in line with the previous morphological analysis demonstrating that O. lupi is an atypical Onchocerca species showing both primitive and evolved characters. The phylogenetic trees generated for the COI sequences of filariae and the wsp and ftsZ sequences of their wolbachiae were congruent with each other, which supports the hypothesis that nematodes and their Wolbachia endobacteria share a long co-evolutionary history.     

Treatment of experimental ureteral strictures by endourological ureterotomy and implantation of stents in the porcine animal model

The objective of this study is to evaluate the dilation of the ureter using endoureterotomy and an expanding-sheath double pigtail ureteral stent in the treatment of experimentally induced ureteral strictures in the porcine animal model. This is a new treatment in the ureteral strictures resolution in Veterinary Urology, although it is not a common affection, it usually appears as a consequence of ureteritis and in the iatrogenic female genital surgery. The experimental study is design in three phases: induction of experimental stricture, diagnosis and treatment of the stricture and follow-up. We have used 10 healthy Large White female pigs. The internal ureteral diameter was measured prior to laparoscopic ligature stricture induction using retrograde ureteropyelography (RUPG). Experimental stricture was diagnosed 4 weeks after intervention, using RUPG and ultrasound, and treated by endoureterotomy and subsequent placement of a double pigtail ureteral stent, which was removed 6 weeks later. The study finished 4 weeks later with measurement of ureteral diameters using RPUG and ultrasound evaluation. Except in one case, all ureters displayed permanent dilation of the strictured area for 10 weeks after treatment (6 weeks with ureteral stent and 4 more weeks without stent). Finally, this technique proved to be effective in cases of short-length and short-living ureteral strictures, and represents a viable alternative to conventional surgery in animals.     

Teratological examination of the insecticide methylparathion (Wofatox 50 EC) on pheasant embryos. 1. Morphological study

Teratogenic effects of methylparathion / Wofatox 50 EC/ and Parathion 20 WP as positive control material were tested in pheasant embryos. On the 12th day of incubation 0.1 ml of the emulsions or suspensions of the insecticides at different concentrations was inoculated into the air space of embryonated eggs. The following dose levels were employed: 27 and 270 mg/kg egg of Wofatox 50 EC, and 10 mg/kg of Parathion 20 WP. Morphological changes were evaluated by macroscopic, skeletal staining and light microscopic examinations of the embryos. Primary hypoplasia or atrophy developed in the cervical musculature /m. longus colli/ accompanied by lordosis and scoliosis of the cervical spine. In most cases we also found cyllosis .     

Acute toxoplasmosis in squirrel monkeys (Saimiri sciureus) in Mexico

Toxoplasma gondii causes fatal multisystemic disease in New World primates, with respiratory failure and multifocal necrotic lesions. Although cases and outbreaks of toxoplasmosis have been described, there are few genotyping studies and none has included parasite load quantification. In this article, we describe two cases of lethal acute toxoplasmosis in squirrel monkeys (Saimiri sciureus) of Mexico city. The main pathological findings included pulmonary edema, interstitial pneumonia, hepatitis and necrotizing lymphadenitis, and structures similar to T. gondii tachyzoites observed by histopathology in these organs. Diagnosis was confirmed by immunohistochemistry, transmission electron microscopy and both end point and real time PCR. The load was between <14 and 23 parasites/mg tissue. Digestion of the SAG3 gene amplicon showed similar bands to type I reference strains. These are the first cases of toxoplasmosis in primates studied in Mexico, with clinical features similar to others reported in Israel and French Guiana, although apparently caused by a different T. gondii variant.     

Analysis of the effect of the bovine adenosine triphosphate-binding cassette transporter G2 single nucleotide polymorphism Y581S on transcellular transport of veterinary drugs using new cell culture models

In commercial dairy production, the risk of drug residues and environmental pollutants in milk from ruminants has become an outstanding problem. One of the main determinants of active drug secretion into milk is the ATP-binding cassette transporter G2/breast cancer resistance protein (ABCG2/BCRP). It is located in several organs associated with drug absorption, metabolism, and excretion, and its expression is highly induced during lactation in the mammary gland of ruminants, mice, and humans. As a consequence, potential contamination of milk could expose suckling infants to xenotoxins. In cows, a SNP for this protein affecting quality and quantity of milk production has been described previously (Y581S). In this study, our main purpose was to determine whether this polymorphism has an effect on transcellular transport of veterinary drugs because this could alter substrate pharmacokinetics and milk residues. We stably expressed the wild-type bovine ABCG2 and the Y581S variant in Madin-Darby canine kidney epithelial cells (MDCKII) and MEF3.8 cell lines generating cell models in which the functionality of the bovine transporter could be addressed. Functional studies confirmed the greater functional activity in mitoxantrone accumulation assays for the Y581S variant with a greater relative V(MAX) value (P = 0.040) and showed for the first time that the Y581S variant presents greater transcellular transport of the model ABCG2 substrate nitrofurantoin (P = 0.024) and of 3 veterinary antibiotics, the fluoroquinolone agents enrofloxacin (P = 0.035), danofloxacin (P = 0.001), and difloxacin (P = 0.008), identified as new substrates of the bovine ABCG2. In addition, the inhibitory effect of the macrocyclic lactone ivermectin on the activity of wild-type bovine ABCG2 and the Y581S variant was also confirmed, showing a greater inhibitory potency on the wild-type protein at all the concentrations tested (5 μM, P = 0.017; 10 μM, P = 0.001; 25 μM, P = 0.008; and 50 μM, P = 0.003). Differential transport activity depending on the genotype together with the differential inhibition pattern might have clinical consequences, including changes in substrate pharmacokinetics (and subsequently pharmacodynamics) and more specifically, changes in secretion of ABCG2 substrates into milk, potentially implying important consequences to veterinary therapeutics.     

Diagnostic radiology of pet and wild birds: a review. I. Radiographic techniques and radiographs of healthy birds.

By the radiographic examination of pet and wild birds, veterinary clinicians may relatively easily obtain additional information that can be used routinely in their everyday diagnostic and therapeutic work. The first part of the present review summarizes the basic technical conditions of radiological examinations, analyses the radiographic features of healthy birds, and describes the procedure and radiological indications of contrast radiography.     

Specific contrast ultrasound using sterically stabilized microbubbles for early diagnosis of thromboembolic disease in a rabbit model

Specific contrast ultrasound is widely applied in diagnostic procedures on humans but remains underused in veterinary medicine. The objective of this study was to evaluate the use of microbubble-based contrast for rapid ultrasonographic diagnosis of thrombosis in small animals, using male New Zealand white rabbits (average weight about 3.5 kg) as a model. It was hypothesized that the use of microbubble-based contrast agents will result in a faster and more precise diagnosis in our model of thrombosis. A pro-coagulant environment had been previously established by combining endothelial denudation and external vessel wall damage. Visualization of thrombi was achieved by application of contrast microbubbles [sterically stabilized, phospholipid-based microbubbles filled with sulfur hexafluoride (SF₆) gas] and ultrasonography. As a result, rapid and clear diagnosis of thrombi in aorta abdominalis was achieved within 10 to 30 s (mean: 17.3 s) by applying microbubbles as an ultrasound contrast medium. In the control group, diagnosis was not possible or took 90 to 180 s. Therefore, sterically stabilized microbubbles were found to be a suitable contrast agent for the rapid diagnosis of thrombi in an experimental model in rabbits. This contrast agent could be of practical importance in small animal practice for rapid diagnosis of thrombosis.     

The pharmacokinetics and metabolism of ivermectin in domestic animal species

The pharmacokinetic properties of drugs are closely related to their pharmacological efficacy. The kinetics of ivermectin are characterised, in general terms, by a slow absorption process, a broad distribution in the organism, low metabolism, and slow excretion. The kinetics vary according to the route of administration, formulation, animal species, body condition, age, and physiological status, all of which contribute to differences in drug efficacy. Characterisation of ivermectin kinetics can be used to predict and optimise the value of the parasiticide effects and to design programmes for parasite control. This article reviews the pharmacokinetics of ivermectin in several domestic animal species.     

Comparison between Haemophilus parasuis infection in colostrums-deprived and sow-reared piglets

The aim of this study was to compare the development of Glasser's disease in sow-reared and colostrum-deprived piglets. Ninety piglets from a commercial pig farm in Spain were used. The farm was positive for Haemophilus parasuis. Fifty-two pigs were sow-reared (SR) and 38 were colostrum-deprived (CD) piglets. The animals were intratracheally inoculated with H. parasuis serovar 5 and sacrificed at 1, 2 and 3 days post-infection. To assess the development of disease, antibody titers, clinical signs, pathological lesions, microbiological isolation and PCR amplification were compared between the groups. Inoculation of SR pigs did not cause clinical signs or lesions of Glasser's disease. In SR pigs, H. parasuis isolation and specific PCR amplification from tissues showed a very low number of positive samples. In contrast, in CD pigs, inoculation resulted in the typical signs and lesions of Glasser's disease. Positive microbiological isolation and specific PCR products were obtained from the majority of the tissues tested, and no antibodies against H. parasuis were detected. The experimental infection using CD pigs describes a successful method to study this microorganism and confirms the important role that maternal antibodies play in protection against clinical signs and disease.     

Adhesion of Escherichia coli K88ab fimbriae to porcine enterocytes: effect on enzymatic activities of the brush border, and cyclic AMP and GMP levels

We have studied the cellular alterations, after in vitro adherence, of purified K88ab fimbriae to membranes of porcine enterocytes. Effects on enzymatic activities as disaccharydases and alkaline phosphatase show low changes. While cAMP levels were decreased (44%), guanylyl cyclase was increased (up to 200%), and levels of cGMP were in consequence significantly affected. This study support the role of cyclic GMP as intracellular mediator for adherence, and suggest their implication in disease, affecting a membrane-mediated mechanisms for guanylate cyclase activation, that is unique in the intestine.