The epizootiological significance of positive bacteriological findings on Mycobacterium tuberculosis and Mycobacterium bovis in humans

The relation between the active form of tuberculosis in persons working in agriculture and incidence of tuberculosis in cattle was analyzed in 1974 to 1978, i.e. in the period after the elimination of bovine tuberculosis in Czechoslovakia (in 1968). M. tuberculosis was isolated in 15 cases and M. bovis in four cases of persons employed by the farms on which the Regional Hygienic Station, Brno, was responsible for the microbiological diagnostics of tuberculosis. Direct contact with animals was demonstrated in eight patients; M. tuberculosis was isolated from seven of these patients and M. bovis from one. Seven cattle herds were exposed to spontaneous infection by M. tuberculosis and in one of them tuberculosis was not demonstrated during complex examination. In three herds the examination revealed only a sensitivity of cattle to mammalian tuberculin. In other three herds tuberculosis was detected by allergic tests, patho-anatomic examination and bacteriological examination. M. tuberculosis in cattle was detected in two herds. The occurrence of bovine tuberculosis caused by a cattle tender with a positive finding of M. bovis in sputum was demonstrated in one herd. Virulence for the tested cattle was found in one strain (isolated from a mesenterial lymph node of cattle) of the four strains of M. tuberculosis used for the experimental infection of 17 animals. On the other hand, in three strains of M. tuberculosis, trials with experimental infection demonstrated only allergy to mammalian tuberculin and changes at the sites of subcutaneous inoculation of mycobacteria of regressive nature; these mostly disappeared within 90 days from infection.     

Diseases diagnosed in replacement layer and breeder chicken flocks in Victoria, Australia, 1977 to 1985

During the period from July 1977 to June 1985, specimens from 766 replacement layer and breeder chicken flocks were submitted to the Veterinary Research Institute, Victoria, Australia, for investigation of morbidity, mortality and, or, poor performance. A total of 5940 necropsies, as well as numerous ancillary tests, were performed. The findings for these flocks are presented and the consequences of some particular diseases noted.     

Number and distribution of Australian veterinarians in 1981, 1991 and 2001

OBJECTIVE: To analyse the number and distribution of the Australian veterinary work-force, and to assess changes in it that have occurred since 1981. PROCEDURE: The postcode and gender of each veterinarian who was registered, resident and apparently working in each state and territory in 1981, 1991 and 2001 was obtained from veterinary board lists, entered on an Excel data base, and analysed using the statistical program SAS System 7 for Windows 95. The Official Australian Postcode Map was used to determine the location of postcode areas, and publications of the Australian Bureau of Statistics provided data on human populations. RESULTS: At the end of June 2001, 6358 veterinarians were registered, resident and apparently working in a state or territory of Australia. This was 100% higher than in 1981. Over the intervening 20 years, the number had increased by 3181, 2001 of whom were female. Between 1981 and 1991 the increase in major cities was 898 and in rural areas 682, of whom 357 were male. Between 1991 and 2001 the increase in cities was 1139 and rural areas 462, of whom only 98 were male. The density of veterinarians in Australia - 330/million people - is higher than in the UK (213/million), USA (218/million) and Canada (250/million). CONCLUSIONS: The relative number of veterinarians in Australia is now higher than in the UK, USA and Canada, and is likely to continue to increase. There is evidence of maldistribution, with many rural practices facing shortages of veterinarians with the experience and inclination to maintain veterinary services over the longer term, and some cities likely to become overcrowded with veterinarians.     

The distribution of invA,pagC and spvC genes amongSalmonella isolates from animals

New molecular diagnostic techniques often rely on hybridization or amplification of specific DNA regions to detect pathogenic bacteria. The choice of genes to be used as probes or as the targets of amplification techniques is critical to the success of these procedures. The genes so used might best be those associated with virulent isolates and having a wide distribution among such isolates. In this study three genes,invA, pagC andspvC, thought to be associated with the virulence of salmonellae, were labelled and used to probe the total DNA from 103Salmonella isolates from animals in an attempt to determine whether these genes might be useful in diagnostic procedures.pagC was detected in 99% of theSalmonella tested, andinvA was detected in 94.2% of the isolates. BothpagC andinvA were detected with a significantly higher frequency thanspvC in isolates from chickens and swine, but no significant difference in detection of these three genes occurred when bovine isolates were examined. Failure to detect any of these genes occurred in only one isolate. Isolates from apparently healthy or from clinically ill chickens and swine could not be distinguished by detecting these three genes. The genes were not detected in the non-Salmonella strains tested. These results suggest that, of these three genes,pagC may be the best choice for use as a probe or polymerase chain reaction target in future detection protocols.Abbreviations df degrees of freedom - H apparently healthy animal - I animal diagnosed clinically as having salmonellosis - LB Luria-Bertani - NDSU North Dakota State University in Fargo, North Dakota - NS not significantly different - NVSL National Veterinary Services Laboratory in Ames, Iowa - PCR polymerase chain reaction - SDS sodium dodecylsulphate - UGA University of Georgia in Athens, Georgia     

A serological and biochemical study of new field isolates of foot-and-mouth disease virus type A in Peru, 1975 to 1981

Three foot-and-mouth disease virus type A isolates recovered from field outbreaks in the Department of San Martin, Peru, during the period 1975 to 1981 were compared with each other, and the South American vaccine strains A24 and A27, by complement fixation (CF), virus neutralization (VN) and polyacrylamide gel electrophoresis (PAGE). Complement fixation and VN tests gave comparable results distinguishing the field isolates from each other and from the vaccine strains. Analysis of the structural polypeptides by PAGE also showed clear differences between all the viruses examined. Samples from tissue culture passaged and mouse adapted strains of one of the field isolates gave identical patterns in PAGE, but differences were observed in the polypeptide pattern of the A24/BRA/55 strain and the Peru vaccine strain, which were serologically indistinguishable. Results illustrate a continued antigenic variation in an endemic area where vaccination has been used; however, asymmetric serological reactions between the A24 vaccine strain and the most recent field isolate indicated that a vaccine incorporating A24 should still give adequate protection.     

Number, distribution and concentration of Australian veterinarians in 2006, compared with 1981, 1991 and 2001

OBJECTIVE: To determine the number, concentration and distribution of veterinarians working in Australia in 2006, and compare with data from 1981, 1991 and 2001. Procedure Data on each veterinarian who was registered, resident and apparently working in each Australian state and territory were obtained from relevant veterinary board lists, entered into an Excel spreadsheet and analysed with SAS System for Windows 8. Other data were obtained from the Official Australian Postcode Map, and the Australian Bureau of Statistics. RESULTS: A total of 7510 veterinarians, of whom 46% were female, were working in Australia in 2006. The rate of increase (230/year) between 2001 and 2006 was greater than for the previous 20 years. The number per million people (360) was 73% higher than in 1981, and more than 30% higher than in the USA and UK. With the establishment of three new veterinary schools the number of graduates, and the total number of veterinarians, will increase further. By 2011 the number of veterinarians is likely to be three-fold greater, and the number per million people two-fold greater than in 1981. The number of veterinarians per million dogs and cats will increase at a greater rate if dog and cat numbers continue to fall. As more than 75% of Australian veterinary work involves dogs and cats this has serious implications for the profession. CONCLUSIONS: Progressively increasing numbers of veterinarians will compete for a constant or diminishing resource--the dogs and cats of Australia. It seems likely that overt signs of oversupply will appear before sufficient numbers of veterinarians enter alternative forms of employment.     

The prevalence, organ distribution and fertility of cystic echinoccosis in feral pigs in tropical North Queensland, Australia

An investigation was carried out to study the prevalence of Echinococcus granulosus hydatidosis in feral pigs (Sus domesticus) in the Charters Towers region of tropical North Queensland. Data were collected from a total of 238 carcasses, which were hunted and shot in the Burdekin River catchment area. Organs of the abdominal, thoracic, and pelvic cavities were examined for the presence of hydatid cysts. In the laboratory, cysts and hydatid cyst fluids were examined under a stereoscopic binocular microscope and a compound microscope. An overall prevalence of E. granulosus hydatid cysts in feral pigs was found to be 31.1%. There was no significant difference in either sex or age between infected and non-infected feral pigs. The predilection sites of cysts were livers (23%) and lungs (62%), with more cysts in lungs (252) than livers (48). The ratio of livers to lungs infected with fertile cysts was 1:4 compared to 1:8 sterile cysts. The overall fertility of cysts was 70.1%. The percentage of fertile cysts in liver and lung was 79.2% and 68.7%, respectively. The diameter of fertile cysts ranged from 15 to over 60 mm. There was no significant difference in size between fertile and non-fertile cysts in lungs. The high prevalence rate and fertility of cysts in feral pigs confirm that feral pigs can take part in the sylvatic cycle of the parasite in the region. The public health significance of this observation is potentially very important.     

The trichostrongyloid parasites of sheep in South Australia and their regional distribution

Summary. The species of trichostrongyloid nematodes present in 376 sheep from different agricultural regions of the state of South Australia were determined.
Parasites encountered in the abomasum were Teladorsagia circumcincta, T. trifurcata, T. davtiani, Camelostrongylus mentulatus, Haemonchus contortus and Trichostrongylus axel. T. circumcincta was the species most commonly encountered, but C. mentulatus was widespread in arid areas. H. contortus was present in a small number of sheep only, mainly in southern areas.
In the small intestine, Trichostrongylus vitrinus predominated in the wetter, southern districts, and T. rugatus in dry, northern areas. T. colubriformis was common, but was rarely dominant. T. probolurus was found in one sheep. Nematodirus filicollis was restricted to wetter, southern areas, while N. spathiger and N. abnormalis were widespread and predominated in dry areas. N. helvetianus was found once. Cooperia species were uncommon; species encountered were C. oncophora, C. surnabada and C. pectinata.
Thanks are due to P. M. Bonnin, E. Moore, S. M. Fitzsimons, F. M. and R. R. Martin and M. G. O'Callaghan for excellent technical assistance, and to members of the South Australian Department of Agriculture, particularly the staff of the Northern Region, for collecting material or helping with the collection.     

The use of discriminant analysis in predicting the distribution of bluetongue virus in Queensland,Australia

The climatic variables that were most useful in classifying the infection status of Queensland cattle herds with bluetongue virus were assessed using stepwise linear discriminant analysis. A discriminant function that included average annual rainfall and average daily maximum temperature was found to correctly classify 82.6% of uninfected herds and 72.4% of infected herds. Overall, the infection status of 74.1% of herds was correctly classified. The spatial distribution of infected herds was found to parallel that of the suspected vector,Culicoides brevitarsis. This evidence supports the role of this arthropod species as a vector of bluetongue viruses in Queensland.The effect of potential changes in temperature and rainfall (the so-called global warming scenario) on the distribution of bluetongue virus infection of cattle herds in Queensland was then investigated. With an increase in both rainfall and temperature, the area of endemic bluetongue virus infection was predicted to extend a further 150 km inland in southern Queensland. The implications of this for sheep-raising in Queensland are discussed.Abbreviations AGID agar gel immunodiffusion     

The distribution of Fasciola hepatica in Queensland, Australia, and the potential impact of introduced snail intermediate hosts

A survey was conducted to establish the distribution of the liver fluke, Fasciola hepatica, in the state of Queensland, Australia, and to evaluate the impact of the introduced snail intermediate hosts, Pseudosuccinia columella and Austropeplea viridis. Serum samples from a total of 5103 homebred cattle in 142 beef herds distributed throughout the state and 523 pooled milk samples from dairy herds from the state's major dairying regions were tested for antibodies to F. hepatica by ELISA. Snails were collected on infected properties around the limits of the F. hepatica distribution. F. hepatica infection was detected in 44 dairy herds and two beef herds. The distribution of infected herds indicates that F. hepatica is established only in southeast Queensland. The distribution there was patchy but the parasite was more widespread than suggested by an earlier survey. The predominant intermediate host species found along the northern limit of the distribution was P. columella. We conclude that the introduction of P. columella and A. viridis has not yet had a major impact on the distribution of F. hepatica in Queensland. However, the presence of P. columella, which is much more adaptable to tropical habitats than the native intermediate host, Austropeplea tomentosa, at the northern limit of the F. hepatica distribution suggests that there is potential for the parasite to expand its range.     

Toxoplasma gondii infection of cats in epizootiological and clinical aspects

A total of 200 cats from a south-western region of Poland were tested for antibodies to T. gondii. 105 (52.5%) examined cats were seropositive for T. gondii. Positive results were found in 16 (50%) out of 30 homeless cats, 33 (55%) out of 60 cats kept in shelters, and 56 (51.85%) out of 108 pet cats visiting outpatients clinics. 70 of pet cats stayed indoor and never left house, the others (38 cats) lived at house, but frequently abided outdoor. The seroprevalence in the last group was higher than in cats kept indoor, in shelters or homeless cats, however the differences were not statistically significant. Among the cats kept exclusively indoor the statistically significant difference in seropositivity was noted between the cats fed raw meat (69.23%) and the ones eating only commercial feed or cooked meat (19.35%), chi2 = 17.24, P < 001. Males were more frequently infected than females, but the differences were not statistically significant. In cats over 5 years old the percentage of positive results was significantly higher than in the younger ones. The ranges of antibody titres measured by LAT (latex agglutination test) were in agreement with ranges estimated by IFAT (indirect fluorescent antibody test). The LAT titres over 1980 IU/ml and IF IgG titres over 1:4000 were found only in cats, in which clinical toxoplasmosis was confirmed.     

The role of the differential complement fixation test, using rough and smooth brucella antigens, in the anamnestic test

To assess the ability of the differential complement fixation test to distinguish vaccinal reactors from infected cattle, approximately 1,000 heifers were tested by the complement fixation test (CFT) using rough and smooth brucella antigens, before the injection of 45/20 vaccine and at 3 and 6 or 10 weeks after vaccination. Before vaccination 91.5% of heifers were negative to the rough antigen but 0.6% were positive with high titre (greater than or equal to 128). By 10 weeks after injection of 45/20 vaccine 97.6% of heifers were positive to the rough CF antigen, at greater than or equal to 8, a majority reaching greater than or equal to 128. Nineteen pre-vaccinal reactors to the standard CFT were killed and Brucella abortus was isolated from the tissues of 14. Twenty-six post-vaccinal reactors were killed and B. abortus was isolated from the tissues of 8. In the 22 B. abortus infected animals the differential CFT classified 9 correctly as infected, 5 incorrectly as vaccination reactions and 8 as inconclusive. The differential CF was ineffective in distinguishing titres resulting from vaccination with 45/20 vaccine from those due to infection.