Distribution of Mycobacterium avium complex isolates in tissue samples of pigs fed peat naturally contaminated with mycobacteria as a supplement

In early 1999, there was an increased incidence of tuberculous lesions in the lymph nodes of slaughtered pigs in the Czech Republic. In part 1 of this study, tuberculous lesions were detected in 140 (62%) tissue samples collected from pigs coming from 15 farms in 15 districts at routine veterinary meat inspections in abattoirs. Mycobacteria were isolated from 37 (16%) tissue samples: 34 Mycobacterium avium subsp. hominissuis isolates and three environmentally derived mycobacteria. In search of infection sources, M. avium subsp. hominissuis was isolated from 38 (79%) samples of peat used as a feed supplement. In part 2 of our study, the head, mesenteric, and inguinal lymph nodes of 117 randomly selected slaughtered pigs from one farm with young piglets fed peat as a supplement were investigated for mycobacterial infection. From 65 (56%) pigs, a total of 76 mycobacterial isolates were identified (56 M. avium subsp. hominissuis isolates, 5 M. avium subsp. avium isolates, 3 M. intracellulare isolates, and 12 environmentally derived mycobacterial isolates). IS1245 restriction fragment length polymorphism (RFLP) types with >20 bands of 45 distinct RFLP types were found in 49 M. avium subsp. hominissuis isolates from pigs (n = 31) and peat (n = 18). Identical RFLP types were found in only four pig isolates. Five randomly selected isolates from pigs and peat were subcultured to six independent clones or colonies. Among the IS1245 RFLP types of 30 clones, identical RFLP types obtained from pigs and peat were identified, which confirmed the hypothesis that peat contaminated with mycobacteria represents a significant source of mycobacterial infection for pigs.

Detection of Mycobacterium avium subsp. paratuberculosis in retail cheeses from Greece and the Czech Republic

We investigated the presence of Mycobacterium avium subsp. paratuberculosis in retail cheeses from Greece and the Czech Republic. We found that 31.7% and 3.6% of our samples reacted positive by PCR and culture, respectively. Consumption of these cheeses is likely to result in human exposure to M. avium subsp. paratuberculosis, albeit at a low level for viable cells.

Distribution of Mycobacterium avium subsp. paratuberculosis in organs of naturally infected bull-calves and breeding bulls

Paratuberculosis, caused by Mycobacterium avium subsp. paratuberculosis, has particular importance in cattle due to the resulting chronic diarrhoea, weight loss, decreased production, infertility and eventual death. While faecal oral route of infection is generally recognised, reports about semen-derived infection are rare. The objective of this work was to assess whether M.a. paratuberculosis may disseminate from the gastrointestinal tract to reproductive organs, and compare this event between naturally infected bull-calves and breeding bulls. Ten bull-calves, aged 6-28 weeks and four breeding bulls were tested by serology, faecal and tissue culture, IS900 PCR and RFLP. In seven bull-calves M.a. paratuberculosis was isolated predominantly from mesenteric lymph nodes (75%); isolates from mucosa of the intestine constituted 25%. In three breeding bulls, M.a. paratuberculosis was isolated both from intestinal mucosa and mesenteric lymph nodes. Head and mediastinal lymph nodes, liver, spleen and semen of bull no. 1 (Holstein-Friesian); testes and epididymis of bull no. 2 (Piemonte); testes, epididymides and seminal vesicle of bull No. 3 (Hereford); and seminal vesicle of bull No. 4 (Simmental) tested positive by culture. Hot-start PCR revealed M.a. paratuberculosis in semen, seminal vesicle and intestinal tissue where culture isolation was difficult. Isolates from bull-calves and breeding bulls were of RFLP types B-C9 and B-C1, respectively. Bull-calves born in infected herd can be sources of infection when later used for natural mating or artificial insemination. Sub-clinically infected bulls release M.a. paratuberculosis into semen, consequently infecting the uterine environment of cows.

Avian tuberculosis in naturally infected captive water birds of the Ardeideae and Threskiornithidae families studied by serotyping, IS901 RFLP typing, and virulence for poultry

Avian tuberculosis was detected in one flock of 38 water birds of the families Ardeideae (n = 20) and Threskiornithidae (n = 18). Mycobacterium avium subsp. avium (MAA, serotype 1, genotype IS901+ and IS1245+) was more often (p = 0.01) detected in tissue and/or faecal samples in 18 (90.0%) birds form the Ardeideae family: little egret (Egretta garzetta), buff-backed heron (Bubulcus ibis), great white egret (Egretta alba), and bittern (Botaurus stellaris) in comparison to two (11.1%) birds from the Threskiornithidae family: sacred ibis (Threskiornis aethiopicus). Avian tuberculosis was not diagnosed in spoonbills (Platalea leucorodia). Tuberculous lesions were found in nine birds. MAA isolates of IS901 RFLP type F-C3 were present in all of the 20 infected birds and in all environmental isolates. A mixed infection with the MAA isolates of three RFLP types F-C3 (tissue isolate), G-C3, and T-C3 (faecal isolates) was found in one sacred ibis. All 20 tissue isolates of IS901 RFLP type F-C3 from 20 birds and 8 environmental MAA isolates were fully virulent in pullets, whilst the isolates of RFLP types G-C3 and T-C3 were non-virulent in pullets. All of the tested MAA isolates had the same IS1245 RFLP "bird profile". In 12 of 20 infected birds with MAA M.a. hominissuis isolates of serotypes 4, 8, 9 and genotype IS901- and IS1245+ were detected and in 8 other birds mycobacteria not belonging to the M. avium complex were found. The presence of MAA in the environment may be a source for further spread of the causal agent of avian tuberculosis among other groups of animals in zoological gardens, farm animals, and also among their keepers.

Clinical pharmacokinetics of ifosfamide in combination with N-acetylcysteine

The pharmacokinetics of ifosfamide were studied in 20 patients with soft tissue and bone sarcomas. Drug was administered as a 30-60 min i.v. infusion at 1.2 or 2.0 mg/m2/day for five consecutive days. Some patients also received 1.5 g/m2 of N-acetylcysteine (NAC) administered 3 times per day during the course of therapy. NAC had no effect on ifosfamide pharmacokinetics. There were significant differences in plasma half-life, area under the concentration-time curve and plasma clearance on day 1 versus day 5 of ifosfamide administration. Myelosuppression and granulocytopenia correlated better with day 1 versus day 5 ifosfamide pharmacokinetics suggesting that the alteration of ifosfamide pharmacology with multiple dosing has a significant effect on drug activity.

Assessment of pulmonary and hematologic toxicities of liblomycin, a novel bleomycin analog

The antitumor efficacy as well as hematologic and pulmonary toxicity of Liblomycin, a new lipophilic analog of bleomycin, was evaluated in BDF1 mice. In comparison to bleomycin which was without any antitumor efficacy against P388 leukemia, a dose of 10 mg/kg Liblomycin administered on a daily schedule for 10 consecutive days resulted in a significant increase in animal survival (% T/C of 190). This therapeutic dose and schedule of drug administration did not produce any evidence of pulmonary histopathologic injury; at a similar dose and schedule bleomycin resulted in greater than 40% consolidation of alveolar lung space. Mouse lung collagen synthesis measured as rate of [3H]hydroxyproline formation was increased almost 4-fold by bleomycin 7 days following a single maximally tolerated i.v. injection (133 mg/kg); in contrast, Liblomycin (60 mg/kg) did not significantly alter the rate of lung collagen synthesis compared to saline injected control animals. Lung function was assessed by whole body plethysmography. Bleomycin produced an increase in breathing rates above control values by day 15 following administration of drug at 10 mg/kg (d1-10). Mice treated with Liblomycin did not exhibit an increased rate of breathing. Liblomycin, in contrast to bleomycin, produced mild and transient leukopenia and thrombocytopenia suggesting that this toxicity will be a limiting one in future clinical trials. The only other toxicity noted in this study was the appearance after repeated intraperitoneal administration of Liblomycin of a hepatic collagenous fibrous capsule. The capsule formation resulted in an abnormal and grossly lobulated liver which was believed to have affected animal survival. Intravenous administration of Liblomycin, however, was not associated with any detectable hepatic injury.

Seroepidemiology of measles in Addis Ababa, Ethiopia: implications for control through vaccination

We undertook a representative survey of measles antibodies in Addis Ababa, Ethiopia 1994, to characterize immunity and transmission. Specific-antibody levels (IU/l) were determined by ELISA for 4654 sera from individuals aged 0-49 years (1805 < 15 years) collected by stratified household-cluster sampling. The proportion seronegative (< 100 IU/l) was 20% (95% CI: 16-25) in children 9-59 months old, declining to 9% (7-12) in 5-9 year olds, 5% (4-7) in 10-14 year olds, and < 1% in adults. The proportion of children (< 15 years old) with low-level antibody (100-255 IU/l) was 8% (7-10). Vaccination and an absence of a history of measles illness were strongly associated with low-level antibody. History of measles vaccination in 9 months to 14-year-old children was approximately 80%. We estimate a primary vaccine failure rate of 21% (12-34) and continued high measles incidence of 22 per 100 susceptibles (19-24) per annum. Our data support the introduction of campaign vaccination in the city in 1998, although higher routine vaccine coverage is required to sustain the impact. The implications of a high prevalence of low-level antibody are discussed.

Evidence that prolonged histamine suffusions produce transient increases in vascular permeability subsequent to the formation of venular macromolecular leakage sites. Proof of the Majno-Palade hypothesis

The aim of this study was to determine whether histamine-stimulated increases in macromolecular efflux are dependent on the formation of specific vascular leakage sites, or whether other mechanisms need to be invoked to explain the increase in macromolecular efflux produced by this inflammatory mediator. Intravital light microscopy was used to localize and quantitate vascular macromolecular leakage sites in the noneverted hamster cheek pouch. Fluorimetric measurements of plasma and suffusate tracer (FITC-D 70,000 mol wt) concentrations were utilized to quantitate changes in macromolecular efflux. In some experiments, the FITC-D was injected intravenously either at the start of or after the start of a prolonged histamine suffusion for estimation of the duration of the vascular FITC-D leakage response. In saline control cheek pouches there were few, if any, visible FITC-D vascular leakage sites and only small increases in the [FITC-D]s. The arteriolar vasodilators papaverine (1 X 10(-5) M) and isoproterenol (1 X 10(-5) M) failed to increase the formation of vascular FITC-D leakage sites, and the magnitude of the increase in [FITC-D]s produced by these agents was similar to that observed in saline controls. Histamine (1 X 10(-5) M) suffused for either 15, 60, or 120 minutes produced marked increases in [FITC-D]s and in the number of venular FITC-D leakage sites. The venular FITC-D leakage sites began to fade after 10-20 minutes, eventually disappearing altogether. In contrast, the [FITC-D]s was markedly increased throughout the 120-minute observation period. Treatment with papaverine prior to and during the 60-minute histamine suffusion failed to prevent the mediator-stimulated vascular leakage response. In contrast, similar treatment with isoproterenol inhibited the histamine-stimulated increases in [FITC-D]s and the formation of venular FITC-D leakage sites. When the tracer was injected intravenously at the start of the 60-minute histamine suffusion (1 X 10(-5) M), the [FITC-D]s and the number of vascular leakage sites were markedly increased. However, when the tracer was injected intravenously 30 minutes after the start of the 60-minute histamine suffusion, there were only minimal increases in [FITC-D]s and the formation of venular leakage sites. These findings suggest that prolonged suffusions of histamine produce transient increases in macromolecular efflux which are dependent on the formation of discrete venular macromolecular leakage sites.(ABSTRACT TRUNCATED AT 400 WORDS)

Bovine tuberculosis: an old disease but a new threat to Africa

Bovine tuberculosis (TB) is a disease characterised by progressive development of specific granulomatous lesions or tubercles in lung tissue, lymph nodes or other organs. Mycobacterium bovis is the causative agent of the disease. Bovine species, including bison and buffaloes, are susceptible to the disease, but nearly all warm-blooded animals can be affected. All species are not equally susceptible to the disease; some are spill-over (end) hosts and others maintenance hosts. In Africa, bovine TB primarily affects cattle; however, infection in other farm and domestic animals, such as sheep, goats, pigs, dogs and cats, is not uncommon. Wild ruminants and carnivores are also affected and are the natural reservoirs of the infectious agent in the wild. Man is also susceptible to the disease, the highest risk groups being individuals with concomitant HIV/AIDS infection. In Africa, human TB is widely known to be caused by M. tuberculosis; however, an unknown proportion of cases are due to M. bovis. This infection in humans is under-reported as a result of the diagnostic limitations of many laboratories in distinguishing M. bovis from M. tuberculosis. None of the national reports submitted to the OIE and WHO by African member states mention the importance of M. bovis in human TB cases. Consumption of unpasteurised milk and poorly heat-treated meat and close contact with infected animals represent the main sources of infection for humans. This review attempts to examine the impact of bovine TB on the health of animals and humans.

Immunogenicity and efficacy of Fermi-type nerve tissue rabies vaccine in mice and in humans undergoing post-exposure prophylaxis for rabies in Ethiopia

Rabies is an acute viral encephalitis that is invariably fatal following the manifestations of clinical signs. To subvert the course of the disease, rabies post-exposure prophylaxis (PEP) is widely utilized. The immunogenicity and efficacy of Fermi-type rabies vaccine produced in Ethiopia was determined in mice subjected to intracranial challenge with rabies virus, and in humans undergoing rabies PEP in Ethiopia. Mice were randomly assigned into 5 groups. Group 1 received 0.25 ml each of phenolized saline intraperitoneally for 14 consecutive days. Mice in groups 2-5 received 0.25 ml of rabies vaccine for human PEP for the same period of time. Blood samples were drawn from the retro-orbital vein of all mice on designated days for the determination of rabies virus neutralizing antibody (VNA) using the mouse serum neutralization test. Mice were subsequently challenged intracranially with rabies virus at a concentration of 64 MICLD50 90 days post initial vaccination. Rabies neutralizing antibody titers in the sera of immunized mice ranged from 4.6 to 25 IU/ml. Booster vaccine doses did not seem to induce significant increases in the immune response of vaccinated mice, all of whom withstood intracranial challenge with rabies virus. Rabies VNA was further determined in 12 patients vaccinated in accordance with the prescribed dosage of Fermi-type vaccine for human rabies PEP. Most had > 0.5 IU/ml of rabies VNA by day 14, and none detectable at day 1. In contrast to mice, booster doses of vaccine may contribute to slightly higher rabies VNA titers in humans but our small sample size, on top of significant defaulter rates in the study participants, limits our interpretation of the effects of booster vaccine doses. The results of this study are the first documentation of the efficacy and immunogenicity of the Ethiopian Fermi type nerve tissue vaccine in both humans and mice.