Biomedical subjects
Publications and source records attributed to R Heusser.
A novel staphylococcal cassette chromosome (SCC) mec from a clinical methicillin-resistant Staphylococcus aureus isolate (ST100/CC5) had a mosaic structure, composed of SCC DNA from several different backgrounds. It harbored two complete ccr loci and a new variant of mec complex B, with DeltamecR1 interrupted by the aminoglycoside resistance transposon Tn4001.
To test the hypothesis that safer sex procedures are less consistently observed by persons under the influence of alcohol, data from the Swiss human immunodeficiency virus (HIV) Prevention Study (HIPS) were evaluated. HIPS is a large prospective cohort study involving 724 HIV-negative and mainly heterosexual subjects who entertain casual sexual contacts. Of the 724 participants, 36% reported that they had had sex while under the influence of alcohol. Of this group, 31% indicated that safer sex procedures were neglected owing to the influence of alcohol. No significant differences with regard to unprotected sexual intercourse were found between subjects who combine sex and alcohol and those who do not. The same was found to be true among subjects with different levels of general alcohol consumption. However, a significant correlation was found between the intensity of alcohol consumption (i.e., the quantity of alcohol intake per sitting) and the incidence of unprotected sexual intercourse. These findings show that the relationship between alcohol consumption and safer sex is complex; they also emphasize the need for preventive efforts to reinforce safer sexual behavior, for example through individual counseling of persons at risk for HIV-infection.
OBJECTIVES: To analyse trends in age at diagnosis for adult AIDS cases reported in Europe and the United States. DESIGN: We used AIDS surveillance data for the seven European countries with the highest cumulative number of AIDS cases reported through June 1994 and for the United States through June 1993. Mean age at AIDS diagnosis over time was calculated by sex, transmission category and country. Linear regression yielded annual increase in age and permitted statistical evaluation of the trends observed. Annual AIDS incidence was calculated for homo-/bisexual men and injecting drug users (IDU) by 5-year age groups over time. RESULTS: We found an overall increase in age at AIDS diagnosis among the main transmission categories in Europe and the United States. The epidemiologic profiles of the two regions were highly similar, despite the lower average age among IDU in Europe compared with the United States (30.6 versus 36.7 years) and lower annual increases in age in the United States. In contrast to homo-/bisexual men, the increase in age at diagnosis is strikingly uniform and pronounced among IDU. Between 1986 and 1993, IDU in all countries exhibited at least a 6-month increase in age at diagnosis per annum. Although annual AIDS incidence remains consistent between various age groups of homo-/bisexual men, IDU aged 30-49 years show continuing increase, whereas their younger counterparts show signs of stabilization or decrease. CONCLUSIONS: Despite different epidemic profiles and prevention policies, the age trends for the European countries examined and the United States were strikingly similar. The meaning of this general increase in age among the main transmission categories and the especially high increase among IDU may provide important insight into epidemic dynamics and intervention assessment.
A review of the literature shows that condoms offer good protection against HIV infection and other sexually transmitted diseases. A series of in vitro experiments demonstrate that quality condoms made of latex are impermeable to HIV. In addition, more than 30 in vivo studies confirm that condoms are highly effective in preventing the transmission of HIV. Condom breakage or slippage is relatively uncommon (1-5%). Most condom failure probably results from incorrect or inconsistent usage. Failures may be minimized by increasing experience, choice of quality condoms and by strictly following instructions for use.
For successful malaria prophylaxis, future travelers need to be informed about the risks of infection and about systematic measures to be taken against mosquito bites. For visits in areas of high transmission, continuous chemoprophylaxis is recommended, whereas in regions with low transmission a stand-by medication for self-therapy is sufficient. Each of these four measures has some problems which are discussed here in addition to the recently published recommendations by the Swiss Working Group for Medical Advice to Travelers.
Primary prophylaxis by a change of behaviour in the population continues to be the only effective possibility to prevent a further spread of the aids epidemic. The most important presupposition for this is the precise knowledge of the ways of transmission and the corresponding protective measures. Informations referring to this must turn up repeatedly and above all free of contradictions at all levels of the preventive campaign. The desired changes of behaviour suppose also a climate of confidence and solidarity. The physician's task of prevention is part of the comprehensive strategy of HIV-prevention in Switzerland (effect in width and depth on population- and target groups and on the individual level). It is naturally the physician's domain to look after and counsel individually. Most variable possibilities of beginning a conversation about Aids prevention offer themselves to him. He should put the indication for this as generous as possible and deal extensively with a possible risky behaviour which might not be conscious to both the patient and the physician. The HIV antibody test is indicated in certain situations, however the pre- and posttest counselling is in any case much more decisive than the result of the test. The preventive measures recommended up to now for the most important ways of transmission (sexual contact, intravenous drug use, perinatal transmission, blood/blood products) are still valid without modification.
From May 1985 to July 1988, 11,445 German residents who had travelled to Africa filled in a questionnaire during the return flight and a second questionnaire sent to them 3 months later. 92.6% of the travellers had been on holiday and 99.3% of these holiday-makers were aware of the risk of malaria. Before and during their stay in the tropics 10,955 travellers (95.7%) had taken the chemoprophylaxis correctly, though in some instances the drugs prescribed were not in accordance with the guidelines existing at the time. However, 3227 of them (35.5%) discontinued the drugs too early, i.e. less than four weeks after their return. Only 4.3% of the travellers had taken proper precautions against mosquito bites. In view of the ever increasing numbers of people travelling to countries where malaria is endemic, doctors and travelers should be provided with more information and should be given more consistent advice on malaria prophylaxis.
General practitioners are in prime position for promoting primary, secondary and tertiary HIV prevention. Counselling is an integral part of their work and a key step towards behavioural change of their patients. Particular attention must be given to counselling before and after the HIV antibody test. So far, the extraordinary potential of general practitioners to educate patients about HIV infection has been used insufficiently. The primary barriers to providing health education are lack of knowledge and discomfort with initiating discussions of sexuality or drugs use rather than lack of time or 'other health priorities', etc. These findings show the need to implement education programmes for physicians and other members of their medical practice. Additionally, patients should be encouraged to take the initiative in starting discussions about HIV. In Switzerland, an education programme for physicians is currently under way.
In order to determine knowledge, attitudes and practices towards malaria prophylaxis, as well as its side-effects and efficacy, a self-administered questionnaire was distributed to European travellers on return flights from tropical Africa to Europe. Between 1985 and 1988 the questionnaire was completed by 44,472 passengers (80.1% of those on board) on 242 flights. A follow-up questionnaire was completed by 42,202 (94.9%) of the same travellers 3 months later. Almost all knew about the risk of malaria, but 10% relied solely on advice from nonmedical sources. While 55.6% had taken at least one measure against mosquito bites, only 4.5% adopted three such measures (used repellents and insecticides and wore long clothing after dusk). Compliance with chemoprophylaxis use was reported by 57.0% of travellers who spent less than 3 months in Africa, compared with 29.2% who stayed 3-12 months. Depending on the antimalaria regimen taken, 11-44% of the travellers experienced adverse effects, while four deaths were attributed to the chemoprophylaxis. The incidence of malaria per month of exposure for travellers who took no chemoprophylaxis was 15.2 per 1000 in East Africa and 24.2 per 1000 in West Africa. In East Africa, the prophylactic efficacy of the currently recommended antimalaria regimens (relative to that of no chemoprophylaxis) was zero for a chloroquine dosage of 300 mg base per week (4 malaria fatalities), 64.1% for a chloroquine dosage of 600 mg base per week (P = 0.03), and 94.0% for mefloquine (P = 0.003).
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In a randomized double-blind study, Swiss adults traveling to tropical countries for 12 to 28 days took a solid formulation of bismuth subsalicylate (1.05 or 2.1 g/day on a twice-daily regimen) or placebo. Efficacy was evaluated in 231 volunteers. Diarrheal incidence was reduced by 41% in persons taking the high dose (P = 0.007) and by 35% in those taking the low dose (P = 0.03) with excellent compliance. No serious adverse reactions occurred, but objectionable taste, constipation, and nausea were seen more frequently with active medication (P = 0.04). Twenty patients provided stool samples: no bacteria were detected in the 8 volunteers who were on active medication, but various bacteria were found in 5 of the 12 patients who had taken placebo (P = 0.04).
Travelers have resorted to a variety of drugs for prevention of diarrhea. No beneficial prophylactic effect has been confirmed for halogenated hydroxyquinoline, lactobacilli, antimotility drugs, ethacridine, and various other agents. In contrast, bismuth subsalicylate (BSS) in liquid form reduced the incidence of diarrhea in students from the United States living in Mexico and in tablet form in volunteers challenged by enterotoxigenic Escherichia coli. In tourists visiting various developing countries, a randomized, double-blind study was conducted in which 390 persons received a total of 2.1 or 1.05 g of BSS daily or placebo in tablet form in two doses. BSS reduced the incidence of diarrhea by 41% in the high-dose group and by 35% in the low-dose group without causing important adverse reactions.