Journal of hygiene, epidemiology, microbiology, and immunology最新文献

Magnesite waste containing largely magnesium oxide (MgO) and a mixture of other metals forms aerosols with a considerable portion of respirable particles when released into the atmosphere. Several animal species (domestic rabbits, Wistar rats, cattle) were used to biologically monitor the accumulation and effects of inhaled magnesite aerosol in two actual locations of the magnesite industry. The study revealed the biological accumulation of magnesium, iron and other metals in the bodies of exposed animals (and F1 animals) as well as specific lesions on tracheal relief, morphological changes in organ microstructure (especially in the lungs, spleen, liver and myocardium), alternations in the reproductive capacity of females, distorted Mg:Ca:P ratio as well as changes in the immune profile. The findings of biological monitoring of animals are consistent with the conclusions of epidemiological studies.

The epidemiology of human papillomaviruses (HPV) was studied in 61 immunocompromised patients (e.g. renal and cardiac transplants; Bowen's disease; genital cancer) undergoing therapy at the University Hospital of Wales at Cardiff U.K. Warts from various sites of these patients were studied for the presence of HPV types 6, 11, 16 and 18 using the dot-blot DNA hybridization technique. Four HPV-16 and one HPV-11 was detected. The presence of HPV-16 in our study is quite significant since it suggests the potential occurrence of genital HPV types in skin warts in immunocompromised patients and hence the need for screening such patients against HPV types. HPV, mainly types 16 and 18 are usually associated with genital cancer, cervical malignancies and cervical intraepithelial neoplasia. The semen of the husband of 30 women with cervical abnormalities and the semen of 30 husbands (control) of wives with normal cervix were tested for HPV-6, 11, 16 and 18. No HPV-DNA could be detected in all of the 60 specimen. This suggests that specimens were either truly negative for any of those types or because virus DNA could present in a small amount less than 5 pg/microliters in some patients. Whether semen plays a role in transmitting HPV is still controversial.

Serum samples were collected from eighty-three leprosy patients and twenty-five healthy controls supposedly not exposed to Mycobacterium leprae infection. Phenolic glycolipid-1 coated latex agglutination test (PGL-LAT) was carried out with the serum samples to detect antibodies specific to M. leprae. Samples showing positive agglutination were 50% in the lepromatous leprosy (LL) group showing no erythema nodosum leprosum (ENL) complications, 66.6% in LL group with ENL complication, 60% in borderline lepromatous (BL) group, 50% in borderline (BB) and 33.3% in borderline tuberculoid (BT). The patients belonging to the tuberculoid (TT) group and most of the long-term treated patients were interestingly negative, and so were sera from all the healthy controls. PGL-LAT developed by us therefore is specific and a fairly sensitive technique to detect antibodies specific to M. leprae and will be very useful in field conditions.

Alpha, beta and delta toxins of Staphylococcus aureus stimulate human peripheral blood lymphocytes to blastic transformation and formation of IgM, IgG and IgA. The toxins are efficient at concentrations that are not toxic for the cells in culture. A dose of a toxin suitable for stimulation is 100 ng/ml but a stimulation can be observed also at 10 ng/ml, in the case of Ig formation even at a concentration of 1 ng/ml. Toxoids are approximately as effective to elicit blastic transformation as the toxins themselves, their efficiency to stimulate Ig formation being somewhat lower but significant. Alpha and delta toxins and toxoids at the appropriate concentration appear to act as medium-strength polyclonal activators of lymphocytes. Beta toxin and its toxoid are weak polyclonal activators.

In Central African Republic, the first cases of resistant P. falciparum to chloroquine occurred in 1983 in non immune expatriate residents on regular chemoprophylaxis. From 1984 to 1991, 950 in vivo tests with a seven days observation period were performed in semi-immune autochtonous children living in seven towns of the country. Chloroquine treatments were given at 25 mg/kg over 3 days period to children with P. falciparum parasitaemia > 500 (634 simplified methods) or > 1000/mm3 (316 WHO standard field tests), usually asymptomatic. Until 1988, the surveys show an absence or a low frequency of chloroquine resistance (usually below 10%) according to the town; since 1989, the resistance has been present in all towns but everywhere with a frequency under 20%. None cases of R III level resistance was observed and all children became or remained asymptomatic at day 7. Until further surveys demonstrate a decreased efficacity of chloroquine, it is advised that chloroquine be used at 25 mg/kg over 3 days period as the treatment of choice in uncomplicated acute malaria in the Central African Republic.

The authors present a short historical review on the developments in the Czechoslovak tropical health studies with special reference to the post WW II period. Perspectives for future expansion are likewise outlined.

During 21 month study of bacterial conjunctivitis among 121 children in two health care centres in Calabar, Nigeria, a total of 90 (74.4%) cases were culturally confirmed. Neonates had the highest age-specific attack rates with 48 (53.3%) cases. Neisseria gonorrhoeae, the predominant pathogen, was recovered from 32 (35.6%) infections; 21 (65.6%) of them from neonates. Cultures of genital swabs of consenting parents of infected neonates as well as those of three female children aged 2-12 years with concurrent vulvo-vaginitis yielded N. gonorrhoeae. Younger women, mostly primi-gravidae were more frequently found to have benefited from peri-natal health care services than older multi-gravidae. Nevertheless, such access to health care services did not appear to influence the frequency of gonococcal conjunctivitis in neonates from the two maternal groups (P < 0.01). Sexual abuse and contaminated fomites were the possible modes of gonococcal infection transmission to older children. Overall, 22 (68.8%) strains of gonococci were resistant to penicillin; 19 (59.4%) were penicillinase-producing Neisseria gonorrhoeae (PPNG), while 5 (15.6%) had chromosomally-mediated resistance. All isolates were sensitive to erythromycin. This study recommends a review of gonorrhoea surveillance in pregnancy to include routine examination of cervical swabs just before delivery.

By indirect immunofluorescence using antigens of hantavirus Hantaan and CG 18-20 on Vero E6 cells were examined 5,827 samples of sera from 5,299 probands of Czechoslovakia. In 49 persons (0.94%) were found antibodies of titres 1:32 and higher. Two groups of elderly farm workers showed a cluster of positive individuals amounting to 9.9% and 29.4% respectively. The ratio of positivities in some other, randomly and specifically selected groups was deep below 1%. The partial results for the group of farmers were confirmed by RIA test. Occasionally antibodies only to one of the hantavirus serotypes, at other time, to both were found. The authors discuss the findings of antibodies of the two serotypes in humans as related to the evidenced existence of two hantavirus antigen serotypes in animals.

The 5th International Conference on Indoor Air Quality and Climate: INDOOR AIR '90 continued a series of international scientific conferences begun in 1978 on a complex, interdisciplinary subject increasingly recognized to be of importance to human comfort, health and productivity, and having important implications for building design and furnishing, office equipment, appliances, cleaning, heating, ventilating, humidifying and air-conditioning. INDOOR AIR '90 constituted a week long program of 542 paper and poster presentations and forum discussions, 100 exhibits, and a public forum. This paper summarizes some of the highlights of this conference and links these to some of the studies reported at earlier INDOOR AIR Conference.

Human serological profiles, and feline serological and fecal profiles were used to study the epidemiology of toxoplasmosis in Santa Clara County, California. The prevalence of human toxoplasmosis was determined to be 42.9% in a test population of 147 women. The prevalence of feline toxoplasmosis was indicated to be 34.8% based on serological analysis of 158 felines. Of 107 cats tested, 6.5% were shedding Toxoplasma gondii - like oocysts in their feces. Statistical analyses of questionnaire data indicated that the major infection sources for seropositive humans in this study were: (1) eating rare-medium cooked beef; (2) exposure to cats; and (3) working in an outside garden. Of these three sources, gardening represented the least risk. The data from questionnaires with reference to age, residence, and eating and toilet habits of owned felines were evaluated and found to show no significant statistical correlation with seropositivity. The infection sources for seropositive felines could not be determined. The plausible significance of feline-human interaction, human consumption of infected meat, and gardening habits is stressed.