Major antigenic groups of rabies virus in Canada determined by anti-nucleocapsid monoclonal antibodies

A total of 123 rabies virus isolates from various geographical areas in Canada were characterized by a panel of 43 anti-nucleocapsid monoclonal antibodies. Four major antigenic groups are found in terrestrial mammals: "Canadian Arctic" from Ontario, Quebec and the Northwest Territories; "south-eastern Georgian Bay" from Ontario; "south mid-central skunk" from Alberta, Saskatchewan and Manitoba; and "Brook's, Alberta skunk" from a restricted area in Alberta. Bat isolates can be divided into 4 major antigenic groups: "B-1" in Eptesicus fuscus from Ontario; "B-2" in a variety of bat species from British Columbia eastward into Ontario; "B-3" in Myotis spp. from Ontario and New Brunswick; and "B-4" in E. fuscus from Alberta and Saskatchewan. A single case of bat to horse transmission of rabies virus is recorded. These street isolates are compared with isolates of fixed virus. Epidemiological aspects are discussed.     

The Susceptibility of Muskrats and Snowshoe Hares to Experimental Infection with a Chlamydial Agent

Muskrats (Ondatra zibethicus) and snowshoe hares (Lepus americanus) were exposed experimentally by various routes to a chlamydial agent (designated strain M56) originally isolated during a die-off of muskrats and snowshoe hares which occurred in Saskatchewan during 1961. Both species were susceptible to experimental infection. Whereas M56 was highly lethal for snowshoe hares (18 deaths/19 exposed), it was less virulent for muskrats (6 deaths/20 exposed).

The degree of susceptibility of muskrats to induced infections with M56 was influenced by the presence or absence of specific antibodies at the time of exposure. A febrile illness was observed in 11 of 20 muskrats. In the six that died, widespread focal necrosis was found in the liver. Following intraperitoneal or oral exposures, chronic infections were established and the agent was recovered from the brain and the small intestine up to 96 days post-infection. Specific antibodies were found in 11.8% of 127 sera of muskrats trapped form the wild in Saskatchewan, the Canadian Arctic, and Wisconsin.

In snowshoe hares, M56 induced an acute, febrile, emaciating illness, and the almost invariable fatal course was short with terminal signs of opisthotonos, convulsions, and hypoglycemia. Snowshoe hares succumbed with intravenous doses of less than ten mouse intracerebral LD₅₀ of M56. The same syndrome was produced by intravenous, subcutaneous, and oral infections. M56 was found in high titers in all tissues examined. The highest titers were found in the liver and spleen which correlated with the pathology observed. M56 was recovered from female rabbit ticks (Haemaphysalis leporispalustris) engorging on experimentally infected snowshoe hares.

     

Rabies diagnosis in western Canada, 1985-1989

The results of laboratory examination of 20460 specimens for the diagnosis of rabies by the standard fluorescent antibody and mouse inoculation tests over a five year period are presented. Specimens were received from British Columbia, Alberta, Saskatchewan, Manitoba, and the Yukon and Northwest Territories. Of those examined, 9.96% were positive. The main reservoirs of rabies were skunks, bats, and foxes. During this observation period a rabies epizootic occurred in skunks in Saskatchewan. When both tests were performed, the fluorescent antibody test was found to agree with the mouse inoculation test in over 99% of cases.     

Laboratory Diagnosis of Rabies in Western Canada (1968-1977)

The results of laboratory examination of 18,086 specimens for the presence of rabies antigen by the fluorescent antibody and mouse inoculation tests over a ten year period are presented. The submissions were received from British Columbia, Alberta, Saskatchewan, the Yukon and the Northwest Territories. Of those examined, 10.74% were positive: however, the incidence of rabies varied widely in the specimens and species submitted, depending on their origin. The principal wildlife reservoirs of the disease appear to be skunks, foxes and bats. A correlation of almost 99% was obtained between the fluorescent antibody test and the mouse inoculation test, indicating that the diagnostic procedures used were highly reliable in identifying rabies-infected animals.     

Rabies in Western Canada 1978-1984

The results of laboratory examination of 22,503 specimens for the diagnosis of rabies by the standard fluorescent antibody and mouse inoculation tests over a seven year period are presented. Specimens were received from British Columbia, Alberta, Saskatchewan, the Yukon and Northwest Territories. Of the 1,445 positive cases, 10.50% involved human contact. The main reservoirs of rabies were skunks, bats and foxes. The reliability of the fluorescent antibody test for the diagnosis of rabies was reaffirmed by agreement with the mouse inoculation test in over 99% of cases.     

Prevalence of antibodies to infectious bovine rhinotracheitis, parainfluenza 3, bovine respiratory syncytial, and bovine viral diarrhea viruses in cattle in Saskatchewan and Alberta

A total of 1745 healthy cattle from 295 farms in Saskatchewan and Alberta was tested by ELISA for antibodies to four viruses. Antibodies to infectious bovine rhinotracheitis (IBR) virus were found in 37.8% of sera (59.5% of properties), to parainfluenza 3 (PI3) virus in 93.9% of sera (99.7% of properties), to bovine respiratory syncytial (BRS) virus in 78.5% of sera (86.6% of properties), and to bovine viral diarrhea (BVD) virus in 40.6% of sera (66.7% of properties)

The prevalence of PI3 viral antibodies among Saskatchewan cattle was not affected by district of origin, breed, sex, age, or vaccination practices, though BRS viral antibodies appeared less frequent in young, male, and unvaccinated animals. Antibodies to IBR and BVD viruses were less prevalent in the Prince Albert/Tisdale districts and in young, male, and unvaccinated animals, but were more common in Holstein cattle. Antibodies to IBR virus appeared less frequent in Herefords. Antibodies were more prevalent in cattle which had been vaccinated against IBR, BRS, and BVD virus infections.

The relatively small number of cattle sampled from Alberta had a similar prevalence of antibodies to PI3 and BRS viruses to that seen in cattle in Saskatchewan, though IBR and BVD prevalence rates were lower.

     

A Serological Survey of Leptospira interrogans serotype pomona in Alberta and Saskatchewan Striped Skunks and Possible Transmission Between Cattle and Skunks

The range of known occurrence of Leptospira interrogans serotype pomona is extended to Alberta in striped skunks (Mephitis mephitis); no evidence of L. sejroe was found. Reacting sera from skunks were confined to the southern portion of Alberta and adjacent Saskatchewan, although a number of reactors were found sufficiently further north in Saskatchewan suggesting that a different mode of infection may be functioning there. Of 95 skunk sera from near a dairy farm infected with serotype pomona 40% were reactors. Of 438 skunk sera from other areas only 5.7% were reactors; that difference was suggestive of transmission from cattle to skunks on the dairy farm. Of 22 skunk sera collected near the dairy farm in summer none were reactors, whereas 52% of skunk sera taken the previous and following winters were. That seasonal difference was not evident among sera from other locations.     

Prevalence of Rabies Virus in Foxes Trapped in the Canadian Arctic

Brains and salivary glands of 521 trapped arctic foxes (Alopex lagopus) submitted from four different settlement areas in the Northwest Territories were examined for rabies by the standard fluorescent antibody and mouse inoculation tests. Rabies antigen was present in 44 of 201 (21.9%) brains from foxes trapped in the Sachs Harbour area, but submissions from Cambridge Bay (127), Spence Bay (93) and Gjoa Haven (100) were negative. Virus was also present in salivary glands from 43 (97.7%) of these 44 positive foxes.

The arctic fox continues to be the main wildlife reservoir of rabies in the Canadian Arctic and foxes in the prodromal stage of the disease pose a particular threat to the trapper. Preexposure vaccination should always be a consideration in this occupational group.

     

Mycoplasma and Associated Bacteria Isolated from Ovine Pink-eye

A mycoplasma was recovered from the untreated conjunctival membranes of nine sheep affected by Pink-eye. It was neither isolated from the conjunctiva of treated animals which were affected nor from the conjunctiva of normal animals either in contact or not in contact with affected animals.

Bacteria found on normal conjunctival membranes were Neisseria ovis, Escherichia coli, Staphylococcus epidermididis, Streptococcus and Bacillus spp.

Bacteria found in clinical cases of Pink-eye were N. ovis, E. coli, a Streptococcus and Pseudomonas spp.

     

Porcine Hemophilus parahemolyticus Pneumonia in Saskatchewan II. Bacteriological and Experimental Studies

The incidence of porcine pleuropneumonia caused by Hemophilus parahemolyticus has shown a marked increase in recent years in some countries. Isolation of a strain distinct from European serotypes was made from a natural outbreak of the disease in pigs in Saskatchewan. Experimentally infected pigs did not develop clinical signs but pathologic-anatomic studies of lungs revealed the presence of necrotizing fibrinous pneumonia with intense proliferation of mesenchymal tissue elements. Similar extensive fibroblastic activity had been found to be a typical feature in the natural infection. It is speculated that the Saskatchewan strain may have invasive patterns different from European serotypes.     

The prevalence of macroscopic sarcocysts in New Zealand cattle at slaughter

A survey carried out to determine the prevalence of visible Sarcocystis spp. infection in 100 slaughtered cattle in a South Island abattoir revealed 64% infected. Although all ages, genders, breeds and export grades were infected, only host age had a statistically significant effect on the infection rate.

Infections were most common in the rectus abdominis and the psoas muscles (47% and 41% respectively). Most infections were light, with less than ten macrocysts seen, though infections of more than 50 macrocysts occurred.

The average macrocyst length was 4.1±0.10 mm (SE) (n = 233), the average cyst wall thickness 5.3 ±0,12 μm (SE) (n = 45).

It is thought that the actual prevalence of infection is higher than that recorded and reasons for this are discussed.     

Epizootic of Western Encephalomyelitis Virus Infection in Equines in Alberta in 1965

The epizootic of equine encephalomyelitis in 1965 in Alberta was proved to be due to Western Encephalomyelitis virus infection by serological findings and virus isolations.

Sixty-three horses of 88 tested, showed a diagnostic rise of CF antibodies to Western Encephalomyelitis virus.

Western Encephalomyelitis virus was isolated from 5 brains of horses. Homologous antibodies were shown in 3 of these animals, the only ones from which blood specimens were received.

For the first time virological evidence is given that Western Encephalomyelitis virus infection in horses is found in more areas of Alberta and in regions situated further North than those previously suspected.

     

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.

     

The Detection of Specific Complement-Fixing Antibodies in Serum of White-Tailed Deer (Odocqileus Virginianus) with Theileria Infection

A complement-fixation (CF) antigen which has been prepared from Theileria infected erythrocytes is capable of reacting to specific serum antibodies of deer acutely infected with Theileria.

No sera from 17 deer known to be free of Theileria infection reacted positively to the CF test. Of 35 tests on sera from 12 infected deer having a parasitemia of 2% or less and no accompanying anemia, only 10 (29%) were positive, 2 (6%) were suspicious, and 23 (66%) were negative. Of 65 tests on 8 acutely infected deer, 49 (75%) were positive, 4 (6%) were suspicious and 12 (18%) were negative. Of the 8 deer in which acute theileriasis occurred all reacted to Theileria antigen at one time or another.

A significant correlation was found between CF titers and the degree of parasitemia in acute infections.

Rabbits were hyperimmunized using erythrocytes from either normal or Theileria infected deer. Reciprocal absorption of the hyperimmune sera with Theileria and normal erythrocytic antigens demonstrated the presence of antibodies specific for Theileria.

     

The importance of ovine arthritis in meat hygiene in New Zealand

Data obtained from faecal samples from 508 domestic cats and 481 dogs, previously found to have a high frequency of Sarcocystis spp. infections, were further examined to provide information on levels of sporocyst shedding and to ascertain the influence of host, environmental and seasonal factors on the prevalence of naturally acquired infections.

Statistical analysis of prevalence data revealed that, of the factors examined, only host age in cats exerted any apparent influence. Infections were significantly more common in cats up to, rather than over, 6 months of age.

Although they tended to be greater in dogs than cats, faecal sporocyst counts in both hosts were generally low, with the majority of infected samples containing 200 sporocysts per gram or less. In infected dogs the highest count recorded was 144,600/g with a mean of 2270/g, and in infected cats it was 11,100/g with a mean of 597/g.     

Immunization of Mice and Chinchillas Against Pseudomonas aeruginosa

The possibility of production of an effective vaccine against Pseudomonas aeruginosa infections in fur-bearing animals was investigated. Twenty-three strains of Pseudomonas aeruginosa isolated from diseased chinchillas and mink were tested in mice for their immunogenic properties. Nineteen of these strains produced good immunity against homologous strains, and three of these produced also good immunity against heterologous strains. Of the remaining four strains two produced moderate immunity and two no immunity.

It was found that 0.05% or 0.5% formalin added to suspensions of Pseudomonas aeruginosa or ultrasonification of the suspension produced better results than 0.5% phenol, 0.3% alcohol or heat at 100°C for half an hour.

Chinchillas vaccinated with two doses of formolized Pseudomonas aeruginosa bacterins were immune for 36 weeks after the second dose, while all controls died within 48 hours after being challenged.

It was found that the protection afforded by the polyvalent bacterin extended beyond the strains included in the vaccine.

A field survey on 34 ranches which included over 7,700 chinchillas showed very promising and encouraging results.

     

Wide Distribution of Pasteurella haemolytica Type 1 Over the Nasal Mucosa of Cattle

Studies on the site of proliferation of Pasteurella haemolytica in the bovine nasal cavity have been carried out.

P.haemolytica were isolated from 15 selected major anatomical areas of the nasal cavity in calves with high numbers of P.haemolytica following shipment from Western Canada. When the organisms were present in the nasal cavity of live animals in low numbers, they were isolated from many, but not all, areas. P.haemolytica was isolated post mortem from one or more selected areas of several nasal cavities in spite of negative antemortem cultures.

By the direct fluorescent antibody technique, P.haemolytica was demonstrated at the surface of nasal epithelial cells. Organisms were not seen in or between epithelial cells nor in the ducts nor alveoli of glands. The findings were similar when high and low numbers of P.haemolytica were present in the nasal cavity.

     

Ollulanus tricuspis in domestic cats — prevalence and methods of post-mortem diagnosis

Ollulanus tricuspus is a parasite of the stomach of domestic cats and other animals, with a worldwide distribution. It can sometimes cause severe gastritis.

Fifty-five cat stomachs were examined for O.tricuspis using three techniques. O.tricuspis was found in seven stomachs 13%) from adult cats; the number of parasites recovered from individual cats ranged from 9 to 119 (mean 54). The prevalence was higher than that previously recorded in New Zealand. Repeated dilution and sedimentation of the stomach contents and mucosal washings was found to be the most reliable detection method, being positive in all of the detected infections. Pepsin/HCI digestion of the stomach mucosa detected only 71% and punch sampling of the mucosa only 29% of these infections. This contrasts with an overseas study indicating that, in heavily infected cats, these techniques are similar in sensitivity. No macroscopic lesions were seen in the stomachs of infected cats.     

Antigenic variants of rabies virus in isolates from eastern, central and northern Canada.

Street rabies virus isolated from 51 specimens from Ontario, Quebec, Manitoba and the Northwest Territories have been typed by a panel of 36 antinucleocapsid monoclonal antibodies. Three main groups were found. The first group comprised those terrestrial mammals originating in Ontario, Quebec and the Northwest Territories. The second group was found in terrestrial mammals from Manitoba. The third heterogenous group was made up of bats from Ontario.     

The Use of Induced Mammary Infections for Evaluating Dry Cow Treatment Products II. Trial of a Proposed Method to Compare Three Levels of Novobiocin

Infections were induced at the end of lactation in all udder quarters of 19 cows by the infusion of 0.2 mL of a 10^-4 dilution in milk of a six hour milk culture of Staphylococcus aureus, strain 305 (A.T.C.C No. 29740). Two right or two left udder quarters were infected at 15 days and the opposite two five days before the last milking of lactation. Following the last milking all four udder quarters of eight cows were treated with 400 mg novobiocin in 10 mL of 2% aluminum monosterate in peanut oil, gelled. All udder quarters of eight other cows were treated with 50 mg novobiocin in the same vehicle and the udder quarters of three cows were treated with the vehicle only.

At calving, eight of 32 quarters treated with 400 mg novobiocin were still infected, as were 18 of 32 treated with 50 mg of novobiocin and all those quarters treated with vehicle only. Results were identical from udder quarters infected 15 and five days before drying off.

No significant differences were found between quarters in milk yield on the last day of lactation, nor the length of the dry period. An increasing number of udder quarters were infected at calving with increase in lactation age of the cow, although the small number of cows would not allow a firm conclusion. A significant difference in results was found between front and hind udder quarters, only five of 32 front quarters were infected at calving as compared to 21 to 32 hind quarters.

The method proposed was found to give essentially the same results as those from a large field trial using the same antibiotic. It should therefore be useful in evaluation trials of new antibiotic products for dry cow treatment.