Low occupational risk of human immunodeficiency virus infection among dental professionals

Hepatitis B vaccination and infection among U.S. dentists, 1983-1992

The hepatitis B vaccine became commercially available in 1982. Since then, health care workers, including dentists, have been encouraged to be vaccinated. This study examines the prevalence of hepatitis B vaccination and infection among U.S. dentists from 1983 to 1992.

Occupational risk of infection with human immunodeficiency virus

The risk of HIV infection in surgical settings is a composite of overlapping risks related to the local prevalence of HIV, the route of exposure to HIV-infected blood, and the susceptibility of the worker. Studies continue to suggest that the risk of blood contact, including percutaneous injuries, remains appreciable. Prevention of such exposures in the operating and delivery room by adoption of safer instruments, work practices, and techniques and by the consistent use of appropriate personnel protective equipment must be viewed as a priority.

Percutaneous exposures to HIV-infected blood. Among dental workers enrolled in the CDC Needlestick Study

The authors found that 19 percutaneous exposures among dental workers occurred both during and after use of instruments such as syringe needles and scalers. Specific information about the device and action associated with an exposure is important for prevention efforts, including safer instruments and work practices. Most of these exposures probably involved smaller, rather than larger, amounts of blood infected with the human immunodeficiency virus. To our knowledge, none of the exposures resulted in HIV transmission to an enrolled dental worker.

Secretory leukocyte protease inhibitor: a human saliva protein exhibiting anti-human immunodeficiency virus 1 activity in vitro

Infection of adherent primary monocytes with HIV-1Ba-L is significantly suppressed in the presence of human saliva. By reverse transcriptase (RT) levels, saliva, although present for only 1 h during monocyte viral exposure, inhibited HIV-1 infectivity for 3 wk after infection, whereas human plasma and synovial fluid failed to inhibit HIV-1 infectivity. Antiviral activity was identified in the saliva soluble fraction, and to determine the factor(s) responsible, individual saliva proteins were examined. Of those proteins examined, only secretory leukocyte protease inhibitor (SLPI) was found to possess anti-HIV-1 activity at physiological concentrations. SLPI anti-HIV-1 activity was dose dependent, with maximal inhibition at 1-10 micrograms/ml (> 90% inhibition of RT activity). SLPI also partially inhibited HIV-1IIIB infection in proliferating human T cells. SLPI appears to target a host cell-associated molecule, since no interaction with viral proteins could be demonstrated. However, SLPI anti-HIV-1 activity was not due to direct interaction with or downregulation of the CD4 antigen. Partial depletion of SLPI in whole saliva resulted in decreased anti-HIV-1 activity of saliva. These data indicate that SLPI has antiretroviral activity and may contribute to the important antiviral activity of saliva associated with the infrequent oral transmission of HIV-1.

Risk for occupational transmission of HIV infection among health care workers. Study in a Spanish hospital

The aim of this study was to evaluate the HIV seroconversion rate associated with different types of occupational exposures in health care workers. A longitudinal study was conducted from January 1986 to October 1992 in a teaching hospital in Spain, where HIV infection is prevalent among patients. Each health care worker was asked to complete a questionnaire regarding age, sex, staff category, lace of exposure, other exposures, type of exposure, body fluid, infected material and HIV status of source patient. These health care workers were then followed up at 6 weeks, 3 months, 6 months and 12 months with repeated test for HIV antibody. Four hundred twenty three reports of occupational exposure were analysed. Nursing was the profession with more exposures (42.8%). Ninety five percent of total exposures were percutaneous, 4% mucous membrane contacts and 1% skin contacts, 88.3% were described as blood contact and 71.8% had resulted from needlestick and suture needles. Exposures from HIV-positive patients comprised 23.2% of occupational exposures. There was a significant difference in the length of follow-up in physicians (p = 0.00009) and nurses (p = 0.00001), when we compared HIV-positive patients with patients in whom the HIV status was unknown or negative. The HIV seroconversion rate was 0.00%. We consider that the risk of acquiring HIV infection via contact with a patient is low, but not zero. Well documented cases of seroconversion have been published.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessing viral retention and elimination in rotary dental instruments

The authors of this article used a laboratory model of herpes simplex virus infection to assess the potential for contamination of dental handpieces by a human viral pathogen. They found that although all the handpieces in the study were fitted with anti-retraction valves, it was not until the units were flushed internally and disinfected externally that the pathogens were eliminated.

Moving from autonomy to responsibility in HIV-related healthcare

No healthcare issue has generated as much ethical debate on the relationship between the individual and society as HIV Infection. In this debate, an appeal is most often made to such principles as autonomy and confidentiality to protect individuals who are HIV positive or who have AIDS from an invasion of privacy thought to be justified by society's need for information. In the first years, this emphasis on the protection of the individual was essential. Even today, there are risks in disclosing one's HIV status. However, as more and more persons become Infected, live longer, and move within the healthcare industry for non-HIV related care, as both patients and healthcare workers, the terms of the debate need to be redefined.

The reluctance of house staff to perform mouth-to-mouth resuscitation in the inpatient setting: what are the considerations?

OBJECTIVE

Medical house staff are required to perform cardiopulmonary resuscitation (CPR) as part of their job responsibilities. Previously it has been shown that house staff are reluctant to perform mouth-to-mouth resuscitation (MMR) in an out of hospital setting. Therefore, whether reluctance to perform MMR extends to the inpatient setting, and, if so, the reasons for this reluctance were investigated.

DESIGN

All 74 internal medicine house officers of a large metropolitan hospital responded to presentations of hypothetical inpatient cardiac arrest scenarios to assess their willingness to perform MMR.

SETTING

A 1200 bed university-affiliated teaching hospital in Los Angeles, California.

SUBJECTS

All categorical internal medicine house officers at this hospital.

INTERVENTIONS

This study is a survey which concerns whether the house officer would perform mouth-to-mouth resuscitation in different hypothetical cardiac arrest scenarios.

RESULTS

Forty-five percent would perform MMR on an unknown patient and 39% would perform MMR in the elderly patient scenario. Only 16% would do MMR on a patient with a small amount of blood on his lips and only 7% would perform MMR on a patient with presumed acquired immunodeficiency syndrome. Medical housestaff were much more reluctant to perform MMR on elderly, trauma, or presumed immunodeficient patients in an inpatient setting than in an outpatient setting. All house staff that indicated their unwillingness to perform MMR cited fear of human immunodeficiency virus infection as their reason.

CONCLUSION

Medical housestaff are quite reluctant to perform MMR in an inpatient setting. Thus, educating the medical house staff about the percent of patients that survive inpatient cardiac arrest and the actual risks of contracting infectious diseases, especially HIV infections, from MMR and preventative measures, such as effective barrier masks, should result in an increased willingness of physicians to perform MMR or mouth-to-mask ventilation on inpatients.

Dentists and AIDS: a survey of knowledge, attitudes, and behavior in Italy

OBJECTIVES

Italy, together with Spain, is second only to France in the total number of AIDS cases in Europe, with over 16,800 as of March 1993. The purpose of this study was to evaluate knowledge, attitudes, and behavior concerning AIDS and infection control among Italian dentists.

METHODS

A questionnaire was mailed to 1,000 dentists randomly selected from the Italian Dental and Maxillo-Facial Association's register of dentists.

RESULTS

Of the 715 dentists responding, 70.7 percent of dentists knew all the main risk groups able to transmit the infection and that semen is a biologic fluid potentially contaminated by HIV virus. This knowledge was greater if the number of patients per week was not higher than 55 and if the dentist had had a previous contact with an HIV-seropositive patient. Only a few (21.1%) knew all the oral manifestations of AIDS. Over 65 percent of the dentists indicated that they would treat HIV-seropositive patients (71.9%) or those with AIDS (66.8%). Dentists were more willing to care for an HIV-seropositive patient if they were involved in specialties with high blood contact, if they had a previous contact with an HIV patient, as the average number of patients per week increased, and if they did not consider saliva as a possible route of transmission of HIV. A small percentage of dentists who had the opportunity to treat patients at risk for AIDS (12.1%) or HIV seropositive (9.4%) refused to treat them. Willingness to treat was the most significant predictor of actual treatment of an infected patient. Only 24.4 percent routinely used all barrier techniques (gloves, masks, and protective eyewear). Predictors of routine use of all barrier techniques were specialties with high blood contact, considering saliva a possible route of transmission of HIV infection, average number of patients per week fewer than 40, and number of years of practice.

CONCLUSIONS

Educational efforts for improving knowledge and finding and implementing ways to motivate dentists to the correct and routine use of infection control procedures are needed.

Multiple herpesviruses in saliva of HIV-infected individuals

Oral infections with human herpesviruses cause increased morbidity in patients infected with HIV. In this study, multiple HHVs were often isolated from the saliva of HIV-seropositive dental patients, but their isolation rate did not differ substantially from rates reported for the general population, except for human cytomegalovirus.

HIV infection and the dentist. 1. The presence of HIV in saliva and its implications to dental practice

The human immunodeficiency virus (HIV) has been detected in all body fluids. The presence and the detection of HIV virus in human saliva are reviewed. Modes of HIV transmission are discussed with particular reference to the possibility and risk of virus transmission via saliva. This risk is considered to be extremely low. The relevance of this information to the practising dentist is discussed and some practical suggestions in infection control are made.

Occupational risk and precautions related to HIV infection among dentists in the Lothian region of Scotland

This retrospective study used a postal questionnaire to measure occupational risks and to assess infection control procedures among 310 dental practitioners. The study comprised general dental practices in the Lothian region of Scotland, Lothian Health Board Community Dental Service and Edinburgh Dental Hospital. Altogether, 217 dental practitioners responded by the due date giving recall of inoculation injuries within the previous 5 years and infection control measures employed. The study revealed that 191 practitioners (88%) had completed a course of hepatitis B vaccination but one-third of them had not been tested for post-vaccination antibody. In 1991, two thirds of dentists (66%: 137 of 207 respondents) wore the same pair of gloves, and 80% of dentists (142 of 177 respondents) wore the same mask, for dealing with more than one patient. The usual practice was to change gloves during sessions (44%: out of 71 dentists) and to change masks for each session or less often (75%: 73 out of 97 dentists). The proportion of dentists who never used gloves fell from 56% in 1981 to 1% in 1991. An autoclave was used for sterilisation by 85% of practitioners in 1991. Reported non-sterile inoculation injuries averaged 1.7 (S.D. = 3.2) injuries per dentist in the previous year with 56% of practitioners having had an injury. The average was 6.8 (S.D. = 15.9) injuries per dentist in the previous 5 years with 76% of practitioners having had an injury. Of recent non-sterile inoculation injuries described by dental practitioners, 30% constituted a moderate or high risk of transmission of infection to the practitioner (43 of 141 described injuries). Combined with HIV seroprevalance rates, probabilities of transmission and numbers of practising dentists, the mean reported number of non-sterile inoculation injuries in the previous 5 years may be used to provide estimates of expected numbers of dental practitioners occupationally infected with HIV in the previous 5 years. U.K. estimates were 0.004 dentists in Lothian region and 0.05 dentists in the Thames region occupationally infected with HIV in the previous five years. Non-sterile inoculation injuries appear to be a common hazard of dental practice. In any year, most dentists are exposed to the risk of blood-borne viral infection. Despite a high reported incidence of such injuries, dental practice within the U.K. appears to carry a low risk of acquiring HIV infection from occupational exposure.

Rotary dental instruments and the potential risk of transmission of infection: herpes simplex virus

A laboratory model of herpes simplex virus infection was used to assess the potential contamination of dental handpieces. When contaminated instruments were treated with surface disinfection and internal chemical disinfection, viable virus was eliminated in all instruments.

Progress in the understanding of HIV infection: an overview

The worldwide epidemic of human immunodeficiency virus (HIV) infection will likely be considered the most important public health event of the twentieth century. During the past 15 years, a wealth of information relating to the epidemiology, diagnosis, natural history, and treatment of HIV infection has accumulated. This article details the recent progress in each of these areas.

Viral infections in the dental setting: potential effects on pregnant HCWs

Occupational exposure of pregnant health care workers to infectious diseases may cause a variety of effects. This article reviews potential effects of viral infections in pregnant health care workers by pathogens transmittable in a dental setting.

Aggregation of human immunodeficiency virus type 1 by human salivary secretions

Human immunodeficiency virus (HIV-1) is generally transmitted by parenteral contact with infected body secretions. Although extensive epidemiological data and familial studies have failed to provide any conclusive data that saliva may act as a vehicle for transmission of AIDS, both professional and public anxieties remain. The present study, as well as others, suggests that salivary secretions may act as inhibitors of HIV-1 replication in vitro. In our study, the inhibitory activity was determined to be associated mainly with secretions obtained from the human submandibular-sublingual glands. Human submandibular-sublingual (HSMSL) and parotid (HPS) salivas were collected and tested for their ability to modulate the replication of HIV-1, using a plaque assay on HeLa/CD4+ cell monolayers. Initial results examining freshly collected salivary samples from ten individuals confirmed the results previously obtained by Fox et al. (1988, 1989). An average plaque reduction of approximately 66% was obtained with HSMSL, in contrast to 34% reduction obtained with HPS. Titration of the inhibitory activity in HSMSL showed detectable levels at a 1:500 dilution. Comparison of inhibitory activity of dialyzed and lyophilized saliva to fresh saliva indicated little difference between the two samples when filtration occurred after the addition of HIV-1. However, the effect of filtration was significantly diminished in the lyophilized samples. Electron microscopic examination of the saliva-HIV incubates revealed the aggregation/entrapment of virus particles by salivary components. These results suggest that human salivary secretions (with HSMSL > HPS) may have a role in modulating the infectivity of HIV-1.

Analyzing dental procedures performed by an HIV-positive dental student

No evidence of HIV transmission was found between an HIV-positive dental student and 163 treated patients.

Detection of salivary antibodies in cats infected with feline immunodeficiency virus

The saliva of cats infected with feline immunodeficiency virus was examined for total immunoglobulin content and antiviral antibodies. Seropositive cats showed an increase in salivary immunoglobulin G levels, which was only partly attributable to the enhanced prevalence of oral inflammatory lesions, compared with the levels in seronegative cats. Immunoglobulin G, but not immunoglobulin M, levels in serum were also increased. Salivary antibodies were determined by indirect immunofluorescence and Western blot (immunoblot) analysis. All but 1 of the 16 seropositive cats examined were positive, while all 16 control cats were negative. The presence of oral lesions was not a prerequisite for antibody detection in saliva. It was concluded that salivary antibody might be usefully exploited for diagnostic and epidemiologic purposes.

What is the dentist's occupational risk of becoming infected with hepatitis B or the human immunodeficiency virus?

Surveys have shown that dentists are reluctant to treat persons infected with the human immunodeficiency virus (HIV). However, dentists are much more willing to treat patients with infectious hepatitis B virus (HBV). This study shows that the annual cumulative risk of infection from routine treatment of patients whose seropositivity is undisclosed is 57 times greater from HBV than from HIV, and that the risk of dying from HBV infection is 1.7 times greater than the risk of HIV infection, for which mortality is almost certain.

Blood-borne Infections Associated with Transfusion

The epidemic of acquired immunodeficiency syndrome (AIDS) and the realization that transmission of human immunodeficiency virus is caused by homologous blood transfusion have changed the way physicians and their patients view the safety of hemotherapy. Considering that nearly four million patients receive the lifesaving benefits of blood transfusions every year in the United States, we need to recognize and reduce the inherent biological complications of this therapy. Currently, a major concern is the transmission of blood-borne infectious agents and the establishment of persistent infection in transfusion recipients, which is apparently facilitated by suppression of the recipient's hematopoietic and immune systems. Education of blood donors, patients, and attending physicians regarding infectious complications of transfusion is essential and remains the most effective procedure for making rational decisions. Before giving blood transfusions, astute physicians should calculate a risk/benefit ratio and communicate it to the patient or family. Potential recipients of transfusions can be assured that the blood supply is safer now than at any time in the past, although there is still a very small risk for the transmission of infectious agents that cause chronic diseases, such as hepatitis, AIDS, neuropathies, and leukemias. It is essential that everyone understands that the goal of a zero-risk blood supply is not attainable. Recent developments in molecular biology and biotechnology, however, provide opportunities for further reduction of infectious complications of blood transfusions.

Human immunodeficiency virus type I. Infection among dentists

The largest collection yet assembled of year-to-year data on the seroprevalence of antibody to HIV in practicing dentists confirms that dentists--along with other health care workers--remain at low risk for occupationally acquired HIV infection.

[Risk of infections by the human immunodeficiency virus (HIV) among health professionals]

To investigate the occupational risk of infection by HIV among health professionals, 36 cases of occupational accidents involving exposure to material potentially infected with HIV, reported at a Brazilian General Hospital (HCFMRP), were studied. Of the injured workers 75% were female and 25% male (ranging from 23 to 49 years old) and just one of them had high-risk behavior of HIV infection. Of these health professionals, 52.8% were nursing auxiliaries, 19.4%, nurses, 13.9%, nursing attendants, 5.5%, laboratory technicians, 2.8% surgery instrumentalist, 2.8% accountants and 2.8% nursing technicians. In 47.2% of cases the workers had a parenteral exposure to blood (needlestick injuries). The right hand and fingers were the body areas most effected. The serologic test to detect HIV antibodies by the ELISA method was required of all the workers. The results were negative and no seroconversion was registered during the one year follow-up period. The professionals were retested one month, 2 months, 6 months and one year after the exposure. In conclusion, the risk of infection by HIV among health professionals of HCFMRP seems to be very low. Continuing education should be provided for health care workers with a view to reinforcing the use of universal precaution, especially those to prevent injuries caused by needles or other sharp instruments.

HIV disease: present status and future directions

This review of the human immunodeficiency virus (HIV) epidemic shows that HIV has had and will have a major impact on dentistry, just as it has had on so many other aspects of medical practice and society. These areas include the prevention of HIV transmission in the dental care workplace, the early and safe care and treatment of those who are infected, and the protection of those who are vulnerable or made more vulnerable because of HIV infection. To do this, the dental professional must be educated about HIV and its diseases, their treatment, and what must be done to prevent HIV transmission. Early recognition and treatment of HIV-related oral diseases have become the norms of practice today. Although more and more dentists face potential exposure to HIV, excellent dental care can be provided while minimizing this risk.

Surgical glove perforation and maxillofacial trauma: to plate or wire?

The technique of interdental wiring was compared with a small-plate osteosynthesis technique (SPO) in a prospective study of surgical glove perforations acquired during the treatment of mandibular fractures. Using the SPO technique there was a significant reduction in the incidence of skin penetrating injuries in the surgeon (P less than 0.005) and assistant surgeon groups (P less than 0.05). The reduction in the incidence of glove perforation in the assistant surgeon group was very highly significant in the SPO series (P less than 0.001). The reduction in the surgeon group was not significant. No difference was noted in the scrub nurse group. The small-plate osteosynthesis technique has the advantage of reducing the risk of intraoperative cross-infection transmitted by hand contamination or penetrating injury. The recommended precautions for preventing the transmission of blood-borne pathogens are reviewed.

HIV infection and the healthcare worker

The perception of degree of risk can vary markedly from actual risk. About 5% of the cases of AIDS and HIV infection in the United States have occurred in healthcare workers, a percentage that has remained stable over time. Nearly all of these infections are related to lifestyle factors, not occupational risk. The risk to patients appears to be very much smaller, but has received even more publicity. Apprehension exists concerning the future framework of our medical care delivery system and who will care for whom. The sensitive handling of legitimate fears and the minimization and balancing of conflicting risks will be a challenging task in the decades ahead.

Occupational risk for hepatitis C virus infection among New York City dentists

Health-care workers have an occupational risk of infection with hepatitis C virus (HCV). However, neither the magnitude of this risk nor the practices associated with it have been defined. Since dentists have numerous patients and are exposed to blood, they are likely to have the maximum risk. Therefore, we have assessed occupational risk for HCV infection among dentists in the New York City area. Individuals who admitted present or previous intravenous drug use or (men) who were homosexual or bisexual were excluded. Demographic, occupational, and behavioural data were recorded, and sera were tested for antibodies to HCV (anti-HCV). Anti-HCV was found in 8 (1.75%) of 456 dentists compared with 1 (0.14%) of 723 controls (odds ratio [OR] 12.9, 95% confidence interval [CI] 1.7 to 573). Anti-HCV was found in 4 (9.3%) of 43 oral surgeons compared with 4 (0.97%) of 413 other dentists (OR 10.5, 95% CI 1.9 to 58). Seropositive dentists claimed to have treated more intravenous drug users in the week (p = 0.04) or month (p = 0.03) before the study than did seronegative dentists. Our findings show that dentists are at increased risk for hepatitis C infection. All health-care workers should regard patients as potentially infected with a communicable bloodborne agent.

Effectiveness of dental office instrument sterilization procedures

To evaluate instrument sterilization procedures in Minnesota, biological indicators were used to monitor 406 sterilizers in 381 dental offices. Findings suggest a general improvement in instrument performance over that of a decade ago, but sterilization failure rates are still too high. Sterilizer operator errors are a major cause of sterilization failures. BIs are useful in monitoring sterilization performance only when sterilization procedures are performed consistently and competently by well-trained staff using adequately maintained equipment.

Blood splashes to the eyes in oral and maxillofacial surgery, and the risks of HIV transmission

The risk of transmission of HIV through blood and saliva splashes to the mucous membranes around the face is unknown. Orthopaedic surgeons are very aware of possible risks and are beginning to take appropriate precautions. This present study indicates that oral and maxillofacial surgeons have similar risk factors, and the minimal precaution of wearing protective glasses should be recommended for all intraoral and extraoral surgery.

Human immunodeficiency virus transmission in health care settings: risk and risk reduction

Surveillance data and case reports document that health care workers (HCWs) risk occupationally acquired human immunodeficiency virus (HIV) infection. Transmission of HIV to patients of an infected HCW during invasive procedures has also been reported. The risk to a susceptible HCW depends on the prevalence of HIV infection among patients, the nature and frequency of occupational blood exposures, and the risk of transmission per exposure. Blood exposure rates vary by occupation, by procedure, and by compliance with preventive measures. Future efforts to protect both HCWs and patients must include improved surveillance, risk assessment, study of postexposure prophylaxis, and an emphasis on exposure prevention, including development of safer medical devices, work practices, and personal protective equipment that are acceptable to HCWs and do not adversely affect patient care.

Dentists, allied professionals with AIDS

With about a million people in the United States infected with HIV, health care providers increasingly will encounter infected patients. To minimize transmission in the workplace, recommended infection control measures, including universal precautions, should be followed strictly.

Dimensional stability of a polyvinylsiloxane impression material following ethylene oxide and steam autoclave sterilization

Polyvinlsiloxane impressions were made from a stainless steel master die machined to stimulate five full veneer crown preparations symmetrically placed in an arch form. Three groups of 10 impressions each were made. Treatment groups were sterilized using an ethylene oxide gas and a conventional steam autoclave. Casts were poured and intrapreparation, height, and diameter measurements were made using a stereomicroscope, a digital electronic caliper, and a 1-inch travel dial indicator. Analysis of dimensional changes for the two groups showed that casts made from impressions sterilized by ethylene oxide are acceptable for use in the construction of fixed or removable prostheses. Casts made from impressions sterilized in a steam autoclave can be used for the fabrication of diagnostic casts and some transitional prostheses, but not for routine construction of crowns or fixed partial dentures.

Dental students' knowledge of AIDS and HIV infection in Helsinki, Finland, and in Dar es Salaam, Tanzania

The purpose of this investigation was to study the knowledge about HIV infection and AIDS among dental students in Helsinki, Finland, and in Dar es Salaam, Tanzania. All respondents knew that HIV is not transmitted via hand-shaking, drinking water, or breathing air. More than half of the students in both countries did not know that HIV can be transmitted via breast-feeding. A higher proportion of students in Dar es Salaam than in Helsinki believed that all HIV-positive persons will get AIDS. Tanzanians recognized the early symptoms of HIV infection better than the Finnish students. Many students in both countries did not mention bisexual men as belonging to the high-risk group. Most of the dental students in Dar es Salaam but only one in five in Helsinki believed that dentists belong to the at-risk group.

Detection of proviral sequences in saliva of patients infected with human immunodeficiency virus type 1

Single samples of saliva collected from 20 human immunodeficiency virus type I (HIV-1) seropositive patients were tested by the polymerase chain reaction for HIV-1 proviral sequences using primers from the long terminal repeat (LTR), gag, and env regions of the virus. Proviral sequences were detected in the saliva of 50% of the patients. Sequential samples of saliva, collected at four different times, from each of six additional patients led to the detection of proviral sequences in 100% of the patients. Since, however, the detection of HIV-1 required not only the highly sensitive polymerase chain reaction, but also multiple samples, it appears that under ordinary circumstances infected cells are present in saliva in low numbers. Although this may explain the lack of transmission of HIV-1 by casual contact through the salivary route to household members and health-care workers, the presence of infected cells in the saliva of a high percentage of patients argues for avoidance of sexually intimate situations involving prolonged and repeated contact with saliva.

Paramedics: knowledge base and attitudes towards AIDS and hepatitis

We surveyed 420 paramedics employed by a large metropolitan fire department to determine the effects of educational seminars on their knowledge base, perceptions, and attitudes about AIDS and hepatitis B. All surveys were completed on an anonymous, voluntary, and confidential basis. Our educational efforts improved the paramedics' knowledge base concerning the medical manifestations of AIDS, identification of risk factors, modes of transmission, and means of infection control, but had no impact on paramedics' fear of contracting AIDS. While paramedics have a strong fear of contracting AIDS, we note that they underestimate their risk of acquiring hepatitis B. Only 17% of paramedics surveyed had received the hepatitis vaccine, despite attending an infectious disease seminar addressing the occupational risks of acquiring hepatitis B infections during the previous year. Further educational efforts to address the paramedics' attitudes about AIDS, as well as to encourage paramedics to recognize hepatitis B exposure as a significant personal health risk, are currently being pursued.

Salivary detection of HIV-1 antibodies using recombinant HIV-1 peptides

Salivary antibodies may play a role in the absence of HIV-1 transmission by saliva. We evaluated the presence of salivary IgG antibodies to HIV-1 using a recombinant ELISA. Whole saliva was collected from 21 HIV-1-seropositive individuals and assayed in an ELISA, ASQ (Beckman Instruments, Brea, CA), consisting of a panel of six HIV-1 recombinant peptides. Saliva samples from 20 individuals demonstrated IgG to one or more peptides and 18 to two or more peptides. Samples from 20 seropositive individuals were reactive with the gp41 peptide, whereas only 12 were reactive with the two gp120 peptides. Nineteen of twenty salivas also had detectable IgG antibodies to HIV-1 by Western blotting. The results indicate that viral-specific IgG antibodies are present in the saliva of a high percentage of HIV-infected individuals and that a recombinant peptide ELISA for saliva might be useful for the detection of HIV-1 infection.

In vitro inhibition of HIV-1 infectivity by human salivas

Inhibitory factors to human immunodeficiency virus type 1 (HIV-1) in saliva may be responsible for the infrequent isolation of virus from saliva and also may account for the marked infrequency of salivary and/or oral transmission of HIV-1. Incubation of HIV-1 with human saliva followed by addition of the mixture to susceptible cells leads to partial or complete suppression of viral replication in vitro. We investigated the inhibitory effects of whole saliva and specific glandular salivas on HIV-1 infectivity as measured by viral-induced cytopathic effects in susceptible cells. Whole saliva contained marked inhibitory activity to HIV-1, strain HTLV-IIIB, and to virus infected cells. Submandibular saliva contained inhibitory activity, but of lesser quantity. Parotid saliva demonstrated no HIV-inhibitory activity. Whole saliva also appeared to contain filterable components that were inhibitory to lymphocyte growth. Passage through a .45 micron pore-size filter eliminated the viral inhibitory activity of submandibular saliva and some of the activity in whole saliva. All salivas except parotid incubated with HIV-1 followed by filtration were inhibitory suggesting that complexing of virus with high molecular weight, submandibular mucins may play a role in viral inhibition.

AIDS: practising safe endoscopy

The emergence of HIV has provoked a widespread reappraisal of infection control practices in endoscopy units. Infection control practices should be applied to all patients alike without recourse to selection or screening. Although there has only been one reported instance of viral transmission at endoscopy, HIV could in theory be transmitted by a contaminated endoscope. Experience suggests that this is more likely to occur from damaged endoscopes, if an unsuitable disinfectant is used or endoscopes are not precleaned. In-use studies have shown that HIV contaminates endoscopes used on patients with AIDS, but in amounts too small to cause infection in tissue cultures. Cleaning in neutral detergent is extremely effective in removing contaminating micro-organisms, including HIV, from endoscopes. Aldehydes are the disinfectants of choice, but any disinfectant may fail if organic material is not removed by cleaning. After thorough cleaning, short disinfection times (e.g. four minutes) ensure inactivation of all relevant micro-organisms except Cryptosporidium and mycobacteria, although in practice even these organisms are likely to be reduced to non-pathogenic levels. Accidental needlestick injuries are the greatest hazard in the endoscopy suite; needles should not be resheathed and biopsy forceps must be handled with great care. The wearing of gloves should become second nature.

Risk of transmission of HIV to home care and health care workers

There are only three known routes of transmission of the human immunodeficiency virus (HIV): (1) exposure to blood via transfusion, sharing of contaminated needles by drug abusers, occupational needle stick or blood spill, unsterile needle injections; (2) sexual transmission; (3) perinatal exposure. There is no evidence for transmission by close interpersonal nonsexual contact or insect vectors. Health care workers are at risk for HIV transmission through accidental parenteral inoculation or extensive exposure to blood on nonintact skin or mucous membranes. Fortunately, population studies indicate that this risk is low and may be further reduced by adherence to simple infection control guidelines. The accumulated information on low rates of occupational transmission of HIV makes unwarranted the treatment of patients with acquired immunodeficiency syndrome (AIDS) or HIV infection as if they were highly contagious in the health care setting.