Mycobacterium fortuitum from lesions of slaughtered pigs in Ibadan, Nigeria.

To ascertain the cause of tuberculous-like lesions in pigs slaughtered in a local abattoir in Ibadan (south-western Nigeria), a total of 516 pigs were inspected over a period of four months, 18 of which had gross lesions suggestive of tuberculosis at post-mortem. Mycobacterial culture and molecular typing (GenoType Mycobacterium CM [Common Mycobacteria] assay) analysis were used to identify and confirm the mycobacteria species responsible for these lesions. Results show that 2.3% (12/516) of the animals screened were infected with mycobacteria; Mycobacterium fortuitum was confirmed in 33.3% (4/12) of these cases. As far as the authors are aware, this is the first report confirming the isolation of M. fortuitum in slaughtered pigs in Nigeria. There is a need to improve on necessary preventive and control measures that will reduce potential sources of mycobacterial infections in pig-rearing herds. These infections may also have public health implications, especially to workers in the pig industry.

Histological observations of bovine tuberculosis in lung and lymph node tissues from British deer.

Deer are recognized as hosts of Mycobacterium bovis and assessing the role of wild cervids in perpetuating tuberculosis among cattle has motivated extensive research on several continents. In this paper, the histopathology of lymph node and lung tuberculous granulomas in M. bovis positive British deer is presented. The overall aim was to seek further insights into the potential for onward transmission from infected deer to other species, including cattle. Samples were obtained from an extensive survey of wild mammals in South-West England and from statutory tuberculosis surveillance. M. bovis culture-positive samples were characterised microscopically as to their stage of lesion advancement, number of acid-fast bacilli and granuloma encapsulation. Seventy percent of the deer developed granulomas containing far greater numbers of M. bovis bacilli than typically reported in cattle. Red and fallow deer had the largest number of poorly encapsulated granulomas often containing many hundreds of bacilli. The results are consistent with infected wild British deer being a potential source of environmental contamination and onward transmission to other species. However, further work on levels of bacillary shedding is required before this can be confirmed.

Pathology of naturally occurring bovine tuberculosis in England and Wales.

The aim of this study was to obtain a contemporary data set of pathology in tuberculin reactor and in-contact cattle in England and Wales. Four hundred animals (200 reactors and 200 in-contacts) from 242 farms located in 14 counties in Western England and Wales were examined. The mean number of lymph nodes (LNs) with tuberculosis (TB)-like lesions per TB-confirmed animal was 1.7 in reactors and 1.5 in in-contact animals. Tuberculous lesions in both reactor and in-contact animals were most commonly observed in the LNs of the thorax, followed by the head and abdomen, particularly the mediastinal, retropharyngeal and tracheobronchial LNs. Twenty-five reactors had macroscopic lesions in the palatine tonsils. Among TB-confirmed cattle, 27% of reactors and 9% of in-contact animals had gross TB-like lesions in the lungs, particularly in the caudal lobes. Gross lesions that were not TB-confirmed were parasitic granulomas (45%), bacterial or mycotic club-forming pyogranulomas (27%) and bacterial abscesses (23%). Diagnostic sensitivity was maximised when bacteriology and histopathology were used concurrently. Stage IV granulomas, alone or in combination with other stages, constituted 63% of lesions, while 16% of lesions were stage I/II granulomas. Caseous necrosis and calcification were common features of the granulomas encountered in natural Mycobacterium bovis infections, even with pathology limited to a small number of sites. Granulomas often covered large areas of histological sections and typically contained only small numbers of acid fast bacilli.

Tuberculosis outbreak in a dromedary racing herd and rapid serological detection of infected camels.

A recent outbreak of tuberculosis (TB) in a dromedary racing herd of 58 animals involved 3 infected animals. Disease was confirmed at necropsy by finding gross lesions from which Mycobacterium bovis (antelope type) was isolated. Sera collected from the camels in this herd were used to evaluate two new serological methods, Multiantigen Print Immunoassay (MAPIA) and rapid test (RT) developed using the lateral-flow technology, in comparison with the intradermal tuberculin tests. Antibodies were found in all three infected dromedaries by both RT and MAPIA, but not in the remaining 55 animals in the herd. With the limited number of animals tested in this study, the serological assays showed the potential for convenient, rapid, and accurate diagnosis of TB in live camels.

Camel tuberculosis--a case report.

An adult male dromedary bull was diagnosed with pulmonary tuberculosis (Tb). The dromedary was severely emaciated and died 2 months after the onset of the disease. It exhibited typical Tb lesions in both lungs and lung lymph nodes. A guinea pig inoculated with lung tissue from theTb camel died after 3 weeks from typical Tb. Mycobacteria were isolated from the dromedary's lung and lung lymph nodes and also from different organs of the guinea pig. The microorganism was identified as member of the antelope clade of the Mycobacterium tuberculosis complex.

The differentiation of Brucella species by substrate specific tetrazolium reduction.

In the development of a tetrazolium reduction assay to replace substrate stimulated oxygen uptake for the identification of Brucella species, nine tetrazolium salts were evaluated. Only the more readily reduced compounds (MTT and INT) detected increased metabolic activity with the more fastidious, slow growing strains and with B. suis strains on L-arginine and DL-ornithine. The assay was optimised with MTT. MTT reduction profiles offered with the medium on which the cells were grown. Cells grown on TSA gave profiles more similar to the published respirometric results than those grown on SDA. The optimal substrate concentration was 0.84 g l-1 and prolonged (> 3 h) exposure to substrate was necessary before adding MTT. MTT concentration was not critical and the OD was proportional to the MTT concentration between 0.03 and > 0.5 g l-1. MTT reduction was linear for 60 min after its addition. The reaction was, therefore, stopped after 60 min by adding formaldehyde solution. The optimised assay was evaluated with 71 strains of Brucella, representing all the species and biovars of the genus. Each strain was assigned to its previously identified species and sub-groups were defined.

The characterisation of Brucella strains isolated from marine mammals.

Small Gram negative coccobacilli isolated from seals, porpoises, dolphins and from an otter road casualty were identified as Brucellae by their colonial and cell morphology, staining characteristics, biochemical activity, agglutination by monospecific antisera and susceptibility to lysis by Brucella specific bacteriophage. Their characterisation, including metabolic profiles, is described. These strains could not be assigned to recognised nomen species of the genus Brucella and it is suggested that they comprise a new nomen species to be called B. maris (sp. nov., type strain 2/94). It is further suggested the nomen species be subdivided into three biovars corresponding to their CO2 requirement, metabolic activity on galactose, dominant antigen and animal host.

Isolation of Brucella species from cetaceans, seals and an otter.

Brucella organisms which differed from the recognised species of the genus, were isolated from nine seals, eight cetaceans and one otter. A method is described for the isolation of Brucella species from sea mammals and the first isolations of Brucella species are recorded from an Atlantic white-sided dolphin (Lagenorhynchus acutus), two striped dolphins (Stenella coeuleoalba), a hooded seal (Cystophora cristata), a grey seal (Halichoerus grypus) and a European otter (Lutra lutra). There were differences in the culture media required for the primary isolation of the organisms and in their dependency on carbon dioxide, Subcutaneous lesions, when present, always yielded a confluent growth. The organisms were isolated from seven of 14 spleen samples and also from the mammary glands, uterus, testes and blood and the mandibular, gastric, iliac, sub-lumbar and colorectal lymph nodes.

Isolation of Brucella melitensis from aborting ruminants in Jordan.

Thirty-four isolates (16.5 per cent) of Brucella melitensis were cultured from 206 samples from aborted, still-born or weak full-term animals and vaginal swabs from aborted animals. Twenty-six of 31 isolates from sheep were B. melitensis biovar 3. Two isolates were biovar 1 and one of these was the vaccine strain Rev 1. The three remaining isolates were from vaginal swabs and were not biotyped since B. melitensis biovar 3 had been isolated from the aborted fetuses. One of two isolates from cattle and one isolate from a goat were biovar 1. The remaining cattle isolate was biovar 3.

The isolation of Brucella melitensis biovar 3 from a testicular hygroma of a ram in a nomadic flock of sheep and goats in western Sudan.

Brucella melitensis biovar 3 was isolated from a testicular hygroma in a ram from a nomadic flock of sheep and goats serologically positive for brucellosis and with a history of occasional abortions. The affected testis was enlarged, extensively damaged and contained fluid. The isolation of this biovar identifies the need for further investigations into the prevalence of brucellosis and the particular biovars involved in nomadic animals.

Clinical manifestations of brucellosis in cattle of the southern Darfur Province, western Sudan.

Ninety-seven adult Zebu cattle with hygromas, 32 with arthritis and two showing long calving intervals were investigated for brucellosis. 92 per cent of hygromatous cattle, 62 per cent of arthritic cattle and both animals having long calving intervals were serologically positive and 65 per cent of milk samples were positive by the Milk Ring Test. Hygromas were found on the jaw, bursa, thigh, flank, hip, shoulder, neck and joints. Hygroma aspirates gave higher titres than sera in the serum agglutination test. IgG1, IgG2 and IgA were detected in all the aspirates and all but one contained IgM. Cattle with hygromas are a potential source of infection to other animals and a serious public health problem.

Brucella biovars isolated from nomadic cattle in the southern Darfur Province of western Sudan.

The occurrence of brucellosis and the identification of biovars of Brucella species isolated from infected cattle were studied in nomadic, semi-nomadic and sedentary populations in the South Darfur Province of Western Sudan. Brucellosis was widespread in the area and in all management systems investigated. Forty-one strains of B. abortus were isolated and all were found to be biovar 6.

Effect of infectious stunting syndrome on the immunocompetence of broilers.

Immune responses and liveweights of broilers affected with the stunting syndrome (group C) were compared with those of unaffected birds from the same premises (group B) and normal control broilers of the same genetic origin (group A). Measurements of cell-mediated immunity were made using the phytohaemagglutinin (PHA) intradermal test and those of humoral immunity by antibody response to sheep red blood cells. Weekly observations were made of birds aged from two to eight weeks. Throughout the investigation the weekly mean weight of affected birds was very significantly lighter (P less than 0.001) than that of unaffected and control birds. From the second to the sixth week, wing web PHA reactions in group C were very significantly less than those in groups B or A (P less than 0.001), and during the seventh and eighth week wattle PHA reactions were significantly less in group C than those in group B (P less than 0.02). No significant differences were detected between the three groups in humoral immunity; the complete, IgG and IgM, antibody levels being closely similar. The significance and possible practical applications of these findings are discussed.