Diagnostic and public health investigation of Mycobacterium tuberculosis infection in a dog in Ontario,Canada

A 4-y-old, female mixed-breed dog was presented to the Ontario Veterinary College for further evaluation of multiple pulmonary and hepatic masses, intrathoracic lymphadenitis, and recent development of a pyogranulomatous pleural effusion. Along with other comprehensive tests, a thoracic lymph node biopsy was performed, and Mycobacterium tuberculosis complex infection was confirmed by real-time PCR. The dog’s condition declined post-operatively, and euthanasia was elected. Postmortem examination confirmed severe granulomatous pneumonia, hepatitis, intrathoracic and intraabdominal lymphadenitis, omentitis, and nephritis. Line-probe assays performed on samples collected postmortem confirmed the species as M. tuberculosis. 24-loci MIRU-VNTR genotyping, spoligotyping, and whole-genome sequencing revealed relations to known human isolates, but no epidemiologic link to these cases was investigated. Given the concern for potential human exposure during this animal’s disease course, a public health investigation was initiated; 45 individuals were tested for M. tuberculosis exposure, and no subsequent human infections related to this animal were identified. Our case highlights the need for more readily available, minimally invasive testing for the diagnosis of canine mycobacteriosis, and highlights the ability of canid species to act as potential contributors to the epidemiology of M. tuberculosis infections.     

2S albumin from buckwheat (Fagopyrum esculentum moench) seeds

Sucrose density gradient centrifugation showed that approximately 30% of total buckwheat proteins migrated with a 2S sedimentation coefficient. The main part of that fraction, polypeptides in the range of molecular mass from 8 to 16 kDa, were water soluble and represented albumins. SDS-PAGE analysis in nonreducing and reducing conditions showed that these polypeptides were not linked by disulfide bonds. The albumins make 25% of total salt soluble proteins, but that content is dramatically reduced under S-deficiency conditions. Determination of amino acid composition showed high methionine (9.2%) and lysine (5.6%) contents. That characteristic offers the possibility of transfer of the genes for individual albumin polypeptides to legumes and cereals limited in those essential amino acids to improve their nutritional quality.     

Anti-Trichinella antibodies detected in chronically infected horses by IFA and Western blot, but not by ELISA

In the Balkan countries, where trichinellosis is a re-emerging zoonosis, it is of great importance to determine Trichinella infection prevalence among the major hosts, including horses. One method for monitoring prevalence is serological surveillance; however, the validity of serological methods in horses is not well understood. The dynamics of anti-Trichinella IgG production and circulating excretory/secretory (ES) antigens were investigated in three horses experimentally-infected with Trichinella spiralis. Horses were slaughtered at 32 week post infection (p.i.). Low worm burdens were found in all three animals. Anti-Trichinella IgG was detected up to 32 weeks p.i. by an indirect immunofluorescence assay (IFA) and by Western blot (Wb), but not by ELISA. The ELISA test detected antibodies for only a short period of time (up to 18 weeks p.i. using ES antigen or up to 20 weeks p.i. using tyvelose-BSA antigen). The presence of circulating muscle larvae ES antigen in sera of infected horses was observed by dot blot from the 4th week p.i. up to the 32nd week p.i.     

Control of the Whitefly Trialeurodes vaporariorum Westw. (Homoptera, Aleyrodidae) on tomato by the new insecticide Acetamiprid

The efficacy of a new class of insecticide (chloronicotinyl) Mospilan 20 SP (a.?i. acetamiprid), compared with Lannate 90 SL (a.?i. methomyl) and Applaud WP 25 (a.?i. buprofezin), in glasshouse control of whitefly (Trialeurodes vaporariorum) on tomatoes, was investigated. All investigated insecticides significantly decreased the number of whitefly larvae, compared with untreated plots where population density grew during the trial. Based on statistical analysis, efficacy of all insecticides on whitefly larvae were in the same category. Some differences occurred 7 days after the third treatment. Deposited egg number was significantly different between checks and each insecticide plot. Efficacy of investigated insecticides, evaluated according to deposited egg number, was also good and in the same category.     

The need for implementation of International Commission on Trichinellosis recommendations, quality assurance standards, and proficiency sample programs in meat inspection for trichinellosis in Serbia

Implementation of methods to control inspection for Trichinella in meat recommended by International Commission on Trichinellosis (ICT), particularly the introduction of the quality assurance standards and proficiency panels for certified analysts is extremely important in Serbia and other countries where Trichinellosis is endemic. In spite of existing regulations, including the inspection of 0.5 g samples of diaphragm by the compression method or by artificial digestion of 1g samples, in Serbia 280 people were diagnosed with clinical trichinellosis after consumption of inspected meat during the period 2001--2002. These outbreaks, which occurred in the municipalities of Kumane, Surcin and Bogatic, were a consequence of inadequate application of inspection methods and insufficient education of some veterinary inspectors. The problem of inadequate veterinary inspection in Serbia can be overcome by strict application of the ICT recommendations for the control of Trichinella with specific emphasis on implementing the quality assurance system (QAS) and proficiency sampling (PS/--PP/panel).     

Control of peripheral nerve myelination by the beta-secretase BACE1

Although BACE1 (beta-site amyloid precursor protein-cleaving enzyme 1) is essential for the generation of amyloid-b peptide in Alzheimer's disease, its physiological function is unclear. We found that very high levels of BACE1 were expressed at time points when peripheral nerves become myelinated. Deficiency of BACE1 resulted in the accumulation of unprocessed neuregulin 1 (NRG1), an axonally expressed factor required for glial cell development and myelination. BACE1-/- mice displayed hypomyelination of peripheral nerves and aberrant axonal segregation of small-diameter afferent fibers, very similar to that seen in mice with mutations in type III NRG1 or Schwann cell-specific ErbB2 knockouts. Thus, BACE1 is required for myelination and correct bundling of axons by Schwann cells, probably through processing of type III NRG1.     

Enteritis associated with Clostridium perfringens type A in 9-month-old calves

Four 9-month-old Simmental male calves were presented with a history of sudden death. The necropsy and microscopic findings allowed a diagnosis of enteritis and severe intraluminal hemorrhage with blood clots in the jejunum, suggestive of jejunal hemorrhage syndrome.     

Epidemiology of Trichinella infection in the horse: the risk from animal product feeding practices

A discovery in 2002 of a Trichinella spiralis-infected horse in Serbia offered an opportunity to conduct needed epidemiological studies on how horses, considered herbivores, acquire a meat-borne parasite. This enigma has persisted since the first human outbreaks from infected horse meat occurred in then 1970s. The trace back of the infected horse to a farm owner was carried out. Interviews and investigations on the farm led to the conclusion that the owner had fed the horse food waste in order to condition the horse prior to sale. Further investigations were then carried out to determine the frequency of such practices among horse owners. Based on interviews of horse producers at local horse markets, it was revealed that the feeding of animal products to horses was a common practice. Further, it was alleged that many horses, particularly those in poor nutritional condition would readily consume meat. A subsequent series of trials involving the experimental feeding of 219 horses demonstrated that 32% would consume meat patties. To confirm that horses would eat infected meat under normal farm conditions, three horses were offered infected ground pork balls containing 1100 larvae. All three became infected, and at necropsy at 32 weeks later, were still positive by indirect IFA testing, but not by ELISA using an excretory-secretory (ES) antigen. This result indicates that further study is needed on the nature of the antigen(s) used for potential serological monitoring and surveillance of horse trichinellosis, especially the importance of antigenic diversity. The experimentally-infected horses also had very low infection levels (larvae per gram of muscle) at 32 weeks of infection, and although the public health consequences are unknown, the question of whether current recommended inspection procedures based on pepsin digestion of selected muscle samples require sufficient quantities of muscle should be addressed. It is concluded that horses are more willing to consume meat than realized and that the intentional feeding of animal products and kitchen waste is a common occurrence among horse owners in Serbia (and elsewhere?). This is a high risk practice which demands closer scrutiny by veterinary and food safety authorities, including the implementation of rules and procedures to ensure that such feeds are rendered safe for horses, as is now required for feeding to swine.