ABSTRACT
The risk for occupational exposure to pulmonary tuberculosis is increasing among municipal workers as they are the poorly paid and poorly educated workers, occupationally exposed to different biohazards, and usually work without adequate protective equipments. The aim of this study is determining the magnitude of pulmonary tuberculosis among municipal street cleaners, identifying some of the associated occupational risk factors, and identifying the DNA fingerprint patterns of mycobacterium tuberculosis isolates among those workers. Three hundred and twenty [320] male municipal street cleaners and 200 male drivers were included in the initial screening procedures of the tuberculosis survey; where they were subjected to a pre-constructed questionnaire, clinical examination, mass miniature radiography [MMR], and tuberculin skin testing. Chest X-ray and CT were done to confirm the diagnosis in subjects with any suspected lesions detected by MMR. Moreover, pulmonary TB suspects underwent sputum examination for acid fast bacilli, sputum culture, and biochemical tests to speciate mycobacterial isolates. Genotyping of Mycobacterium tuberculosis isolates, from the diagnosed cases with active pulmonary TB, was done using polymerase chain reaction amplifying the DNA fragments between insertion sequence IS6110. The study revealed that municipal street cleaners had significantly higher risk for Mycobacterium tuberculosis infection, as detected by tuberculin skin testing and chest radiography, than did the controls [OR=3.88, 95% CI; 2.4-6.19 and OR=3.02, 95 % CI; 1.07-9.22, respectively]. Moreover, higher percent of the street cleaners [3.4%] were classified as pulmonary tuberculosis suspects compared to the controls [1%]; however the difference between both groups of workers was not of statistical significance. Pulmonary tuberculosis disease was confirmed in 7 out of 320 street cleaners [2.2%]. Moreover, long duration of employment and bad street status were found to be associated with pulmonary TB disease in such workers. Finally, genotyping of Mycobacterium tuberculosis isolates from the 7definite cases of pulmonary TB, revealed 2 distinct sets of fingerprint patterns; this may suggest that these workers acquired TB from 2 different sources of infection. The study concluded that: Genotyping of M. tuberculosis isolates is mandatory in the study of TB epidemiology. Municipal street cleaners are at increased risk for occupational acquisition of Mycobacterium tuberculosis infection and contracting pulmonary TB disease
ABSTRACT
Ammonium molybdate is an essential trace element in plants and animals as a cofactor for enzymes and also, it is an environmental pollutant. Sixty adult male albino rats were used to investigate the adverse effects of ammonium molybdate on the bone, brain, spinal cord and chromosomes. The rats were equally divided into 3 groups. The 1[st] group was left without treatment and used as a negative control group, the 2[nd] group was daily intragastrically administered saline for 30 days and was used as a positive control group and the 3[rd] group was daily intragastrically administered ammonium molybdate in a dose of 33 mg /kg body weight [1/10 of the lethal dose fifty] for 30 days. At the end of the study ten rats from each group were sacrificed, necropsied and specimens from the bone, brain and spinal cord were collected for histopathological examination. The remaining ten rats of each group were used for studying the chromosomal pattern of bone marrow cells. Histopathological examination of the rats of the 3[rd] group [ammonium molybdate group] showed reduction in the thickness of the bone trabeculae with formation of numerous osteoid fractures and fissures of the epiphysis and necrotic osteocytes. There is also separation between the cortical bone from the periosteum and the endosteum. The bone marrow cavity contains numerous large fat cells with lacked hemopoietic activity. The brain showed congestion of meningeal and cerebral blood vessels, edema, gliosis and neuronophagia. The spinal cord showed satillitosis, gliosis in the grey matter and encephalomalacia and demyelination in the white matter. Regarding cytogenetic study of the bone marrow cells, molybdenotic rats showed a significant increase in the incidence of chromosomal aberrations as terminal chromatid deletions, chromosomal fragments and ring chromosomes when compared with the control group. It could be concluded that, ammonium molybdate is genotoxic and can produce toxic effects on the bone, brain and the spinal cord of adult male albino rats