Analogy between lymphotropic human retroviruses and large animal retroviruses

The family Retroviridae comprises some fifty viruses in three subfamilies: Oncoviridae, Lentiviridae and Spumaviridae. A better understanding of retroviral pathobiology has resulted from the rapid developments in knowledge of the molecular biology of normal and cancerous cells as well as retroviruses. Genomic relatedness was found between two human T cell leukemia viruses and bovine leukemia virus, similarly, some relatedness appears possible between human AIDS (acquired immunodeficiency syndrome) virus and lentiviruses of large animals. Because of their genomic relatedness, retroviruses from man and animals could theoretically form recombinants during in vitro manipulation. Therefore persons who work with retroviral materials should follow established laboratory practices to control infectious agents.     

Analogie entre les rétrovirus humains lymphotropes et les rétrovirus des grands animaux

The family Retroviridae comprises some fifty viruses in three subfamilies: Oncoviridae, Lentiviridae and Spumaviridae. A better understanding of retroviral pathobiology has resulted from the rapid developments in knowledge of the molecular biology of normal and cancerous cells as well as retroviruses. Genomic relatedness was found between two human T cell leukemia viruses and bovine leukemia virus; similarly, some relatedness appears possible between human AIDS (acquired immunodeficiency syndrome) virus and lentiviruses of large animals. Because of their genomic relatedness, retroviruses from man and animals could theoretically form recombinants during in vitro manipulation. Therefore persons who work with retroviral materials should follow established laboratory practices to control infectious agents.     

Concentrations sériques et biodisponibilité sanguine du chloramphénicol chez les bovins

Serum concentrations and factors affecting the blood bioavailability of chloramphenicol in bovine

The authors have compared the serum concentrations and the factors affecting blood bioavailability of chloramphenicol after intramuscular administration of canadian commercial preparations containing 500 mg/mL of antibiotic.

The animals (dairy cows and heifers) received each drug (20 mg/kg) in one or two injection sites. The serum samples, analysed by colorimetric or microbiological methods, showed that considerable differences in concentration exist between the two methods.

The evolution of biodisponibility factors proved identical in both cases. It appears that therapeutic levels of chloramphenicol are reached only by drug A for four to five hours.

The usual dosage (2-10 mg/kg), by intramuscular route, is not sufficient to attain these active concentrations using the other drugs. However, the important variability obtained during the experiment and reflected in the standard deviation values, has not proved that drug A has a better bioavailability based on the criteria of the only microbiological analysis.

     

Enzymes Sériques pour le Diagnostic de la Nécrose Hépatique Aigüe Expérimentale

The activity of certain serum enzymes ornithine carbamyl transferase (OCT), serum isocitric dehydrogenase (SIC-D), total serum lactic dehydrogenase (LDH) and its isoenzymes (LD₁ and LD₅) was evaluated as a mean of assessing experimental hepatic necrosis on dogs treated with CCl₄. Measurement of activity levels of these enzymes, seldom carried out in veterinary clinical pathology, was made together with tests commonly used in our laboratories: serum glutamic pyruvic transaminase (SGPT), serum glutamic oxalacetic transaminase (SGOT) and serum alkaline phosphatase (SAP), cholesterol, bilirubin and prothrombin time. Measurement of the level of OCT was useful in the diagnosis of liver necrosis. The SIC-D level was important during the first four days of the experiment, but on subsequent days, the enzymatic activity was practically normal. Because of the wide variations of LDH serum levels in normal animals and since many factors influence its activity, the measurement of this enzyme and its isoenzymes was not a good index in the diagnosis of canine liver necrosis. The evaluation of cholesterol and bilirubin was judged of secondary importance because these metabolites are not specific to hepatic problems.     

Comparative features of retroviral infections of livestock

Retroviral infections of livestock have become of increasing importance due to their usefulness as comparative models for human retroviral infections and their effects upon animal health and marketability of animals and animal products nationally and internationally. This paper presents a perspective on the retroviruses of economic concern in veterinary medicine with emphasis on the importance of understanding the modes of virus transmission and the species specificity of the viruses. The retroviruses reviewed include the oncovirus, bovine leukosis virus, and the lentiviruses, equine infectious anemia virus; maedi/visna virus, caprine arthritis-encephalitis virus and bovine visna-like virus. The comparative features amongst these animal retroviruses and those of humans must be recognized by the veterinary and medical professions since the similarities in virus replication and spread by blood transfer can provide important clues in controlling and perhaps preventing human retroviruses infections, such as the human immunodeficiency virus.     

Prévalence des infections à Salmonella spp. chez les bovins et les équins de l'Hôpital vétérinaire d'enseignement de la Faculté de médecine vétérinaire de l'Université de Montréal.

Bacteriologic detection of Salmonella spp. from feces of animals admitted to Veterinary Teaching Hospital of the Faculty of Veterinary Medicine, University of Montréal, in Saint-Hyacinthe was carried out during a 1-year period to estimate the prevalence of bovine and equine salmonellosis. Prevalence at the time of hospitalization was quite low: 1.4% in cattle and 1.7% in horses. Incidence was 15.1 cases/100 animal/year in cattle and 38.7 cases/100 animal/year in horses. Serotype typhimurium was the most prevalent in both species. In cattle, cases were evenly distributed over the year. In horses, a recrudescence of cases and a obviousness of transmission were apparent in April 1996.     

Présence de facteurs R chez des souches d'entérobactéries pathogènes isolées d'animaux domestiques, et plus particulièrement du chien

Strains of enterobacteria (nine Escherichia coli and two Salmonella) isolated from primary or secondary infections in the dog, cat, pig, calf and kangaroo were studied for the presence of extrachromosomal drug resistance factors (R factors). Seven strains of E. coli and two strains of Salmonella transferred resistance involving the following antibiotics: streptomycin, ampicillin, chloramphenicol, neomycin and tetracycline. All strains harboring R factors transferred streptomycin resistance and the identified resistance patterns were as follows: Sm Am, Sm Te, Sm Neo, Sm Am Te, Sm CI Neo and Sm Am CI Te. The levels of resistance observed were comparable for all donor strains and their converted recipients.

Strains of E. coli harboring R factors were isolated from three dogs that had died of either otitis (followed by a generalized infection), enteritis or bronchopneumonia — secondary to distemper. The bacteria isolated from cats were recovered at the necropsy of animals that had died of purulent pleuresy and feline panleukopenia. The other strains (two Salmonella and one E. coli were isolated from fatal enteric diseases in the pig, calf and kangaroo.

     

Implications of simian retroviruses for captive primate population management and the occupational safety of primate handlers.

Nonhuman primates can be naturally infected with a plethora of viruses with zoonotic potential, including retroviruses. These simian viruses present risks to both captive nonhuman primate populations and persons exposed to nonhuman primates. Simian retroviruses, including simian immunodeficiency virus, simian type D retrovirus, simian T-lymphotropic virus, and gibbon ape leukemia virus, have been shown to cause clinical disease in nonhuman primates. In contrast, simian foamy virus, a retrovirus that is highly prevalent in most nonhuman primates, has not been associated with clinical disease in naturally infected primates. Although it has been shown that human retrovirus infections with human T-lymphotropic virus and human immunodeficiency virus originated through multiple independent introductions of simian retroviruses into human populations that then spread globally, little is known about the frequency of such zoonotic events. In this article, exogenous simian retroviruses are reviewed as a concern for zoo and wildlife veterinarians, primate handlers, other persons in direct contact with nonhuman primates, and other nonhuman primates in a collection. The health implications for individual animals as well as managed populations in zoos and research institutions are discussed, the cross-species transmission and zoonotic disease potential of simian retroviruses are described, and suggestions for working safely with nonhuman primates are provided.     

Une étude expérimentale sur la variation du taux d'anticorps sériques suivant le cycle évolutif des oestres du cheval

The changes of antibody titers in the sera of colts infested naturally or artificially with Gasterophilus have been determined in relation to the life cycle of this arthropod using passive hemagglutination, complement fixation, double diffusion techniques and saline extracts of antigens from the third larval stages of Gasterophilus intestinalis and G. nasalis.

In the sera of the infected animals the hemagglutinating antibodies were present at low titers at the third week post-infestation by using somatic extract of G. intestinalis and at the seventh week in case of G. nasalis. At eight weeks post-infestation the antibody titers reached their maximum 1:8192 (G. intestinalis) and 1:4096 (G. nasalis), then dropped at 12 weeks post-infestation.

The complement fixing antibodies were present occasionally between the seventh and 11th weeks after infestation. Precipitating antibodies were absent in all sera.

     

Présence de la maladie bactérienne du rein chez les salmonidés au Québec

Presence of the bacterial kidney disease in salmonid fish in Quebec During the summers of 1979 and 1980, wild and hatchery fish were analysed for the presence of the bacterial kidney disease (BKD) agent in salmonid fish in Quebec by the indirect immunofluorescence technique. The causative agent of BKD was detected in all hatcheries tested. Ten to 25% of the fish were positive. The presence of this agent was independent of age and species. We were unable to detect the BKD in fish from the rivers in the northern part of Quebec (over the 50th parallel).     

Les protéines totales et leurs fractions dans le sérum et dans les sécrétions endométriales chez la vache atteinte d'infertilité sine materia

Total proteins, albumine and globulins of serum and uterine secretions were evaluated in two groups of 15 normal and 15 repeat breeder cows. Cyclic significant variations of all studied parameters were observed in uterine secretions of normal cows although only total proteins showed the same pattern in repeat breeder cows where individual variations were noted to be very important. Concentrations of total proteins, albumin (P<0.05) and β globulins (P<0.01) were different between the two groups during either the estrous or the postestrous period. Concentration of proteins in uterine fluid was higher in normal breeder cows during postestrus and diestrus.     

Electrolytes des sécrétions intra-utérines bovines lors d'infertilité sine materia

Serum and uterine secretions Na, K, Ca, Mg and P were studied in 15 normally reproducing and in 15 repeat-breeder cows. No cyclical variations were noted for these elements in the serum whereas the normal group showed cyclical and significant K, Mg and P variations (P <0.05) in the uterine secretions.

The concentration of the studied uterine elements, with the exception of P, correlated with the concentration of their homologue in the serum at different stages of the cycle. It is believed that the concentration of serum Na, K, Mg and Ca maintains the intrauterine concentrations at the physiological level for the survival of the gametes and the embryo.

Significant differences in the uterine concentrations of Na, K and P were noted between the groups at different stages of the cycle. These various concentrations as well as the nonsignificant variations of the uterine secretions might explain the infertility in the abnormal group.

     

Rhinotrachéite Infectieuse Bovine Chez Les Vaches Laitières au Québec

An outbreak of infectious rhinotracheitis affecting four herds of dairy cattle was observed in the Province of Quebec, the general characteristics of which are the same as those reported in the infection of feedlot cattle.

However, a 25% average decrease in the milk production of affected herds was noticed during the present infection, thus stressing a particular economic aspect. The nature of the viruses isolated during this outbreak and those described previously in North America is identical.

     

Seroprevalence of feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) in shelter cats on the island of Newfoundland,Canada

Feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) are retroviruses found within domestic and wild cat populations. These viruses cause severe illnesses that eventually lead to death. Housing cats communally for long periods of time makes shelters at high risk for virus transmission among cats. We tested 548 cats from 5 different sites across the island of Newfoundland for FIV and FeLV. The overall seroprevalence was 2.2% and 6.2% for FIV and FeLV, respectively. Two sites had significantly higher seroprevalence of FeLV infection than the other 3 sites. Analysis of sequences from the FeLV env gene (envelope gene) from 6 positive cats showed that 4 fell within the FeLV subtype-A, while 2 sequences were most closely related to FeLV subtype-B and endogenous feline leukemia virus (en FeLV). Varying seroprevalence and the variation in sequences at different sites demonstrate that some shelters are at greater risk of FeLV infections and recombination can occur at sites of high seroprevalence.     

Les électrolytes du sang et des sécrétions endométriales de la vache à la suite d'une glucocorticothérapie

The effect of two synthetic glucocorticoids, 9_α-fluoroprednisolone acetate and dexamethasone (9_α-fluoro, 16_α-methylprednisolone) was studied on 12 normally breeding cows. Na, Mg, K, Ca and P concentrations were evaluated in the serum and in the uterine fluid at four stages of the estrous cycle.

No significant changes were noted in Na and Ca concentration in either serum or uterine fluid. On the other hand, significant changes in the Mg, K and P were observed. Both drugs have caused a decrease in the content of Mg in the serum (P<0.05) during diestrus, a fall in the level of uterine K (P<0.01) during proestrus and a decrease of P during proestrus both in serum (P<0.001 after dexamethasone treatment) and in uterine fluid (P<0.001 for both drugs).

It is obvious that the two drugs change the chemical composition of blood and endometrial secretions. This could jeopardize the survival of the spermatozoids and of the ovum as well as the fertilization and the implantation processes.

     

General principles of retrovirus immunodetection tests.

Because infecting retroviruses contain protein and glycoprotein antigenic determinants that can be readily distinguished from host cell determinants, the development of immunologic detection systems, immunodetection tests, or immunoassays capable of identifying antigens of some retroviruses (oncoretroviruses) in blood, body fluids, or cells is possible. Conversely, detection of antibodies produced by animals against some infecting retroviruses can also be used to identify current infections of lentiretroviruses and some oncoretroviruses. Studies of various microorganisms by various immunodetection systems indicate that the most specific and sensitive assays are immunofluorescence, radioimmunoassay, and immunoblot (western blot) analysis, followed by sensitive but less specific ELISA and agglutination assays, and finally by even less sensitive but very specific isolation in culture and double immunodiffusion techniques. The first test used routinely for clinical detection of any retrovirus was the immunofluorescent antibody test, introduced in 1972, for detection of FeLV infection in pet cats. Since then, tests for human retroviruses, the human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2 and the human T-cell lymphotropic virus types I and II (HTLV-I and HTLV-II) have been introduced for routine use in human medicine. Recently, retroviral tests for a second feline retrovirus, the feline immunodeficiency virus (FIV) have been introduced in veterinary medicine. General principles of sensitivity, specificity, true-positive and -negative rates, false-positive and -negative rates, and positive and negative predictive values apply to all methods used for detection of retroviral infections.     

Infection à Dermatophilus congolensis chez une vache laitière, au Québec

Dermatophilus congolensis infection in a dairy cow in Quebec     

Leucémie lymphoïde chez deux chiens

Lymphoid leukemia in two dogs