The role of internists during epidemics, outbreaks, and bioterrorist attacks

Internists are well-positioned to play significant roles in recognizing and responding to epidemics, outbreaks, and bioterrorist attacks. They see large numbers of patients with various health problems and may be the patients' only interaction with the medical community for symptoms resulting from infectious diseases and injuries from radiation, chemicals, and/or burns. Therefore, Internists must understand early warning signs of different bioterrorist and infectious agents, proper reporting channels and measures, various ways that they can assist the public health response, and roles of different local, state, and federal agencies. In addition, it is important to understand effects of a public health disaster on clinic operations and relevant legal consequences.

Improving influenza vaccination rates of high-risk inner-city children over 2 intervention years

PURPOSE

Influenza immunization rates among children with high-risk medical conditions are disappointingly low, and relatively few data are available on raising rates, particularly over 2 years. We wanted to determine whether interventions tailored to individual practice sites improve influenza immunization rates among high-risk children in inner-city health centers over 2 years.

METHOD

A before-after trial to improve influenza immunization of children was conducted at 5 inner-city health centers (residencies and faith-based). Sites selected interventions from a menu (eg, standing orders, patient and clinician reminders, education) proved to increase vaccination rates, which were directed at children aged 2 to 17 years with high-risk medical conditions. Intervention influenza vaccination rates and 1 and 2 years were compared with those of the preintervention year (2001-2002) and of a comparison site.

RESULTS

Influenza vaccination rates improved modestly from baseline (10.4%) to 13.1% during intervention year 1 and to 18.7% during intervention year 2 (P <.001), with rates reaching 31% in faith-based practices. Rates increased in all racial and age-groups and in Medicaid-insured children. The increase in rates was significantly greater in intervention health centers (8.3%) than in the comparison health center (0.7%; P <.001). In regression analyses that controlled for demographic factors, vaccination status was associated with intervention year 1 (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.6-2.2) and with intervention year 2 (OR, 2.8; 95% CI, 2.3-3.4), as well as with practice type. Adolescents had lower vaccination rates than children 2 to 6 years old (OR, 0.6; 95% CI, 0.5-0.7).

CONCLUSIONS

Tailored interventions selected from a menu of interventions modestly increased influenza vaccination rates over 2 years at health centers serving children from low-income families. We recommend this strategy for faith-based practices and residencies with 1 practice site, but further research is needed on multisite practices and to achieve higher influenza vaccination rates.

Community-acquired methicillin-resistant Staphylococcus aureus: prevalence and risk factors

Reference/Citation: Salgado CD, Farr BM, Calfee DP. Community-acquired methicillin-resistant Staphylococcus aureus: a meta-analysis of prevalence and risk factors. Clin Infect Dis.20033613113912522744.

Clinical Question: What are the prevalence rates and risk factors associated with community-acquired methicillin-resistant Staphylococcus aureus (MRSA)?

Data Sources: Studies were identified by searching MEDLINE (January 1966–February 2002) and abstracts from scientific meetings (1996–2001). Reviews of citations and reference lists were performed to identify additional eligible studies. The search terms included Staphylococcus aureus, infection, colonization, methicillin resistance, community-acquired, community-onset, prevalence, frequency, and risk factors.

Study Selection: The search was limited to English-language investigations identified from the electronic and manual searches. Studies were divided into 2 groups, as follows: group 1, retrospective or prospective studies that reported the prevalence of community-acquired MRSA (CA-MRSA) among hospital patients who were colonized (presence of bacteria without infection) or infected with MRSA; and group 2, studies that reported the prevalence of MRSA colonization in the community. The studies were evaluated independently by 2 authors, and case reports were excluded.

Data Extraction: Data extraction and study quality assessment procedures were not fully explained. The outcome measures for hospital patients were definitions of CA-MRSA used in the study, prevalence of CA-MRSA, sample size, number and type of risk factors assessed, and number of patients with ≥1 health care–associated risk factor. The studies were grouped based on type, retrospective or prospective. The pooled prevalence of CA-MRSA was calculated for each group (retrospective or prospective) and was limited to the prevalence among patients with MRSA. The proportion of patients who reported ≥1 health care–associated risk factor was also calculated. The outcome measures among community members were prevalence of MRSA, sample size, number and type of risk factors assessed, number of members with ≥1 risk factor, and MRSA strain type, when available. The studies were grouped based on the population surveyed (surveillance cultures, contacts with MRSA-colonized individuals, or sport team members or day care contacts). The pooled prevalence of MRSA colonization and the proportion of members with ≥1 reported risk factor were calculated for each of the study populations listed above. The proportion of CA-MRSA strains that represented typical nosocomial (infection that develops in the hospital) strains was also determined. Chi-square analysis was performed to compare proportions and to determine heterogeneity among the studies.

Main Results: Specific search criteria identified 104 studies for review, of which 57 met inclusion and exclusion criteria. Thirty-nine studies focused on CA-MRSA among hospital patients who were colonized or infected with MRSA. Of these, 32 groups (27 retrospective, 5 prospective) reported the prevalence of CA-MRSA using clinical specimens. Seven groups identified risk factors of CA-MRSA among patients previously diagnosed with MRSA. Thirteen different definitions of CA-MRSA were used in 31 of these studies, and 8 groups did not report the definitions used. The isolation of MRSA within 48 hours of hospital admission, with or without recent admission to a hospital or long-term care facility, or previous history of MRSA colonization were the most common definitions in the studies.

The risk factors included recent hospitalization (range, 1–24 months before identification of MRSA infection or colonization), recent outpatient visit (usually within 12 months), recent nursing home admission (usually within 12 months), recent antibiotic exposure (range, 1–12 months), chronic illness (eg, end-stage renal disease, diabetes, or malignancy), injection drug use, and close contact with a person who had risk factor(s) for MRSA acquisition. The presence of health care–associated risk factors was examined in 17 of the retrospective studies, and the median number of factors studied was 2 (range, 1–6). Among 4121 patients in these studies, 86.1% were found to have ≥1 health care–associated risk factor. All authors of prospective studies (5) examined health care–associated risk factors, and the median number of factors studied was 4 (range, 2–4). Among the 636 patients, 86.9% had ≥1 health care–associated risk factor. In the 7 studies with 515 patients previously diagnosed with MRSA, 84.7% had ≥1 health care–associated risk factor. The most common risk factors assessed in the 17 retrospective studies were recent hospitalization and chronic illness requiring health care visits.

The pooled CA-MRSA prevalence was 30.2% (range, 1.9%– 96%) among 5932 patients from the 27 retrospective studies and 37.3% (range, 18.2%–51.2%) among 636 patients from the 5 prospective studies. Eighteen groups reported the prevalence of MRSA colonization in the community. Ten of these reported MRSA prevalence using surveillance cultures, 4 examined colonization status of household contacts with discharged hospital patients with nosocomial MRSA colonization, and 4 reported colonization status of sports team members or day care contacts of persons colonized with MRSA. In the 10 surveillance studies, the pooled MRSA colonization prevalence was 1.3% (95% confidence interval [CI], 1.04%–1.53%; range, 0.2%– 7.4%) among 8350 community members. Nine of these studies were stratified based on culture samples taken before the assessment of risk factors, and among 4825 people, the pooled MRSA colonization prevalence was 2.1%. When examining health care–associated risk factors, the median number of factors studied was 5 (range, 1–10), and 47.5% with MRSA had ≥1 health care–associated risk factor. The risk factors included those previously identified. In the remaining surveillance study, the MRSA colonization prevalence was 0.20% among 3525 people without prior health care contact. Compared with subjects in the 9 stratified studies with a health care contact, subjects in this study were 90% less likely to have MRSA (relative risk, 0.10; 95% CI, 0.05–0.21). Cultures for 3898 subjects in 7 of the 10 surveillance studies were obtained at the time of a hospital admission, an outpatient clinic visit, or an emergency department visit, and the pooled prevalence of MRSA colonization was 1.8%. In 3 studies in which cultures were obtained outside of a health care facility (schools, day care centers, homeless shelters, or military bases), the pooled MRSA colonization prevalence among 4452 subjects was reported to be 0.76%. Therefore, subjects in a health care facility were 2.35 times more likely to carry MRSA than were subjects outside of a health care facility (95% CI, 1.56–3.53). In one study examining 94 subjects in a semiclosed community, the prevalence of MRSA colonization was 7.4%. These subjects were 36 times more likely to carry MRSA than were subjects who were not in a semiclosed community (95% CI, 13.7–94.7).

The studies also identified 70 MRSA isolates (pure form of an organism in a microbial culture) from subjects who reported no health care–associated risk factors. Strain typing was performed with 32 isolates, and 29 (91%) isolates were similar to strains identified in hospitals. The colonization status of 191 household contacts of 93 patients with nosocomial MRSA colonization discharged from the hospital was examined in 4 studies. The results demonstrated that 17.8% of the contact subjects were colonized with a strain of MRSA having the same antibiogram (record of the susceptibility of bacteria to antibiotics) as the index case (initial individual with the strain). The authors reported that subjects who had household contacts with MRSA-colonized patients were 14 times more likely to be colonized than were community subjects without a known MRSA contact (95% CI, 9.8–20.1). In 4 studies examining 517 sports team members or day care contacts of persons known to be colonized with MRSA, 5.4% demonstrated colonization of MRSA with the same strain as the index case.

Conclusions: Based on the available data, the prevalence of MRSA among community members without health care–associated risk factors was relatively low. However, 85% of hospital patients diagnosed with CA-MRSA and 47.5% of healthy community members colonized with MRSA were found to have ≥1 health care–associated risk factor. The risk factors identified were recent hospitalization, outpatient visit, nursing home admission, antibiotic exposure, chronic illness, injection drug use, and close contact with a person with risk factor(s). Most MRSA colonization occurred among community members who had health care–associated risk factors or contact with persons with risk factors. The evidence indicated that control of MRSA in the community may require control of MRSA in the health care setting (hospital, health care office, and nursing home). The absence of a standardized definition for CA-MRSA and questions regarding the actual site of colonization versus acquisition should be considered in the interpretation of these findings.

Association between infectious diseases and type 1 diabetes: a case-crossover study

BACKGROUND

To investigate the role of infectious diseases in the development of type 1 diabetes, this study estimated the relative risks of type 1 diabetes immediately after infectious diseases.

RESEARCH DESIGN AND METHODS

A case-crossover design was employed. Information on infectious diseases during 407 d before the onset of type 1 diabetes was collected from medical records and parents' interviews for 260 patients in Chinese type 1 diabetes registry. The frequency of infectious diseases in 42 d before the onset of type 1 diabetes was compared with either the usual frequency of infectious diseases over the past year or the actual frequency of infectious diseases in a comparable 42-d control period.

RESULTS

Forty-eight (18%) patients were reported to have infectious diseases during this period based on medical records and interviews with parents. The relative risk of type 1 diabetes onset was markedly elevated to 10.1 (5.6, 17.9) immediately after infectious diseases, suggesting the role of infections as a precipitator. The relative risk decreased gradually before and after 42 d and was similar between male and female patients.

CONCLUSION

The results showed that infectious diseases are associated with a large and transient increase in the risk of type 1 diabetes during 42 d after the infection.

Autophagy: A protective mechanism in response to stress and inflammation

Autophagy is one of the intracellular systems that is responsible for protein trafficking (degradation/recycling) in eukaryotic cells. This ubiquitous process contributes to cytosolic homeostasis, but its deregulation is often associated with various pathologies, including neurodegenerative diseases and cancer and pathologies with an altered inflammatory response. This review provides an overview of autophagy and discusses its regulation, function and future therapeutic possibilities, with a focus on the role of autophagy in inflammation.

Infectious diseases epidemiology

In this glossary the authors have reviewed old and new terms contemporarily used in the infectious disease epidemiology. Many of these concepts were established throughout the 19th century and at the beginning of the 20th century (classic terms), however, the meanings of old terms have been revised and new terms are continually being added. This glossary has therefore reviewed the classic and the more recently established terminology defining the most relevant terms contemporarily used in this field.

Blocking anthrax lethal toxin at the protective antigen channel by using structure-inspired drug design

Bacillus anthracis secretes three polypeptides: protective antigen (PA), lethal factor (LF), and edema factor (EF), which interact at the surface of mammalian cells to form toxic complexes. LF and EF are enzymes that target substrates within the cytosol; PA provides a heptameric pore to facilitate LF and EF transport into the cytosol. Other than administration of antibiotics shortly after exposure, there is currently no approved effective treatment for inhalational anthrax. Here we demonstrate an approach to disabling the toxin: high-affinity blockage of the PA pore by a rationally designed low-molecular weight compound that prevents LF and EF entry into cells. Guided by the sevenfold symmetry and predominantly negative charge of the PA pore, we synthesized small cyclic molecules of sevenfold symmetry, beta-cyclodextrins chemically modified to add seven positive charges. By channel reconstitution and high-resolution conductance recording, we show that per-6-(3-aminopropylthio)-beta-cyclodextrin interacts strongly with the PA pore lumen, blocking PA-induced transport at subnanomolar concentrations (in 0.1 M KCl). The compound protected RAW 264.7 mouse macrophages from cytotoxicity of anthrax lethal toxin (= PA + LF). More importantly, it completely protected the highly susceptible Fischer F344 rats from lethal toxin. We anticipate that this approach will serve as the basis for a structure-directed drug discovery program to find new and effective treatments for anthrax.

Innogenetics NV

Innogenetics NV is a Belgium-based international biopharmaceutical company that has applied its know-how and synergies in molecular biology, immunology and virology to build two distinct businesses: a specialty diagnostics business grounded in personalized medicine, and a pharmaceutical business that is developing therapeutic vaccines. The advantage of this dual model is that the growing revenues from the profitable specialty diagnostics business partially support the development of its biopharmaceutical pipeline. The company employs some 600 persons, with affiliates in Germany, Spain, Italy, France, and the USA.

Emerging trends in international law concerning global infectious disease control

International cooperation has become critical in controlling infectious diseases. In this article, I examine emerging trends in international law concerning global infectious disease control. The role of international law in horizontal and vertical governance responses to infectious disease control is conceptualized; the historical development of international law regarding infectious diseases is described; and important shifts in how states, international institutions, and nonstate organizations use international law in the context of infectious disease control today are analyzed. The growing importance of international trade law and the development of global governance mechanisms, most prominently in connection with increasing access to drugs and other medicines in unindustrialized countries, are emphasized. Traditional international legal approaches to infectious disease control--embodied in the International Health Regulations--may be moribund.

The U.S.-Mexico Border Infectious Disease Surveillance project: establishing bi-national border surveillance

In 1997, the Centers for Disease Control and Prevention, the Mexican Secretariat of Health, and border health officials began the development of the Border Infectious Disease Surveillance (BIDS) project, a surveillance system for infectious diseases along the U.S.-Mexico border. During a 3-year period, a binational team implemented an active, sentinel surveillance system for hepatitis and febrile exanthems at 13 clinical sites. The network developed surveillance protocols, trained nine surveillance coordinators, established serologic testing at four Mexican border laboratories, and created agreements for data sharing and notification of selected diseases and outbreaks. BIDS facilitated investigations of dengue fever in Texas-Tamaulipas and measles in California-Baja California. BIDS demonstrates that a binational effort with local, state, and federal participation can create a regional surveillance system that crosses an international border. Reducing administrative, infrastructure, and political barriers to cross-border public health collaboration will enhance the effectiveness of disease prevention projects such as BIDS.

Efficacy of killed virus vaccine, live attenuated chimeric virus vaccine, and passive immunization for prevention of West Nile virus encephalitis in hamster model

Results of experiments evaluating the efficacy of three immunization strategies for the prevention of West Nile virus (WNV) encephalitis are reported. Immunization strategies evaluated included a killed virus veterinary vaccine, a live attenuated chimeric virus vaccine candidate, and passive immunization with WNV-immune serum; all were tested by using a hamster model of the disease. Each product protected the animals from clinical illness and death when challenged with a hamster-virulent éwild-type WNV strain 1 month after initial immunization. The live attenuated chimeric virus vaccine candidate induced the highest humoral antibody responses, as measured by hemagglutination inhibition, complement fixation, and plaque reduction neutralization tests. Although the duration of protective immunity was not determined in this study, our preliminary results and the cumulative experience of other virus vaccines suggest that the live attenuated chimeric virus provides the longest lasting immunity.

Print media coverage of risk-risk tradeoffs associated with West Nile encephalitis and pesticide spraying

When mosquito-borne West Nile virus emerged in the United States in 1999 and triggered pesticide spraying, society was faced with a controversy over an important risk-risk tradeoff-the risks of pesticide exposure versus those of West Nile encephalitis. Effective public communication about risk-risk tradeoffs is important because it can assist individuals and society in investing resources optimally. This study examined how effectively major North American print media in the year 2000 provided information on this risk-risk tradeoff. My colleagues and I found that the print media were generally ineffective in providing precise information about pesticide risks and in comparing risks of pesticide exposure with those of West Nile encephalitis. The media were also ineffective in mentioning the efficacy of pesticide spraying or comparing the economic costs of pesticide spraying with those of West Nile encephalitis. We suggest that greater effort in collecting and reporting precise risk information, fostering more active relationships between journalists and scientists/public health professionals, and recognizing biases resulting from preconceptions can help improve reporting by the print media and public health agencies on risk-risk tradeoffs associated with emerging insect-borne infectious diseases. These efforts could help improve public health by improving decision making related to the control of insect-borne diseases.

Dengue hemorrhagic fever in infants: research opportunities ignored

The age distribution of cases of dengue hemorrhagic fever and dengue shock syndrome (DHF/DSS) in infants under the age of 1 year are reported from Bangkok, Thailand, and for the first time for Ho Chi Minh City, Vietnam; Yangon, Myanmar; and Surabaya, Indonesia. The four dengue viruses were isolated from Thai infants, all of whom were having a primary dengue infection. Progress studying the immunologically distinct infant DHF/DSS has been limited; most contemporary research has centered on DHF/DSS accompanying secondary dengue infections. In designing research results obtained in studies on a congruent animal model, feline infectious peritonitis virus (FIPV) infections of kittens born to FIPV-immune queens should be considered. Research challenges presented by infant DHF/DSS are discussed.

Immunizations in pediatrics: an update

A Vaccine Evaluation Center has been established in Canada to evaluate vaccines from the developmental stage through to post-marketing surveillance. Special populations need special treatment, particularly day care attendees, children infected with HIV, immunocompromised patients, children who have had a splenectomy, premature infants, the hospitalized child, the traveller, health care workers, and pregnant women. Real and imaginary adverse reactions, their management, and their presentation are discussed. The use of acetaminophen prophylaxis to minimize the most common adverse reactions to diphtheria-pertussis-tetanus-polio immunization is recommended. The most remarkable of the new developments in modern vaccines is the recombinant hepatitis B vaccine.

Urinary tract infection in children: diagnosis and treatment

The history and the physical examination are important and rewarding in the assessment of urinary tract infection in children. Urinary tract infection is usually an ascending infection; periurethral colonization is fundamental to its pathogenesis. It is important to treat predisposing factors, such as poor personal hygiene, diarrhea, and diaper rash. Parents should be specifically instructed on the proper procedures for introital and foreskin cleansing. To minimize the risk of urinary tract infection, children should be encouraged to void frequently and instructed not to hold their urine. Antibiotics should be chosen after taking into account the susceptibilities of the common bacterial pathogens and antibiotics received by the child. Consideration of the symptoms and signs of urinary tract infection is important to develop an appropriate treatment plan.

AIDS and the Family Physician: Survey of Practices in AIDS Counselling and HIV Antibody Testing

In January and February of 1988, a questionnaire was sent to family physicians affiliated with family practice teaching departments in Toronto to determine whether there was any consensus among family physicians as to which patients they counselled about AIDS and to whom they recommended antibody testing for HIV. Ninety-seven out of 126 questionnaires were answered, for a response rate of 77.0%. More than 90% of the physicians reported discussing AIDS and its prevention with patients in high-risk groups, sexual partners of such patients, and those with multiple sexual contacts. More than 90% recommended HIV antibody testing for patients in high-risk groups who requested it. For discussing AIDS with all sexually active patients, however, there was much less consensus in the reported physician practices.

Information for travellers' physicians

Physicians can obtain advice about international travel for their patients from many different sources of information. The authors review some of the most common sources based on their experience at the International Travellers' Clinic operated by the New Brunswick Department of Health and Community Services in Fredericton. They identify readily available handbooks and periodicals and compare two computer software programs.

'Imported' sexually transmitted diseases

A sexual history should be routinely obtained from all travellers. Those whose symptoms indicate a sexually transmitted disease may need to be investigated for unusual infections. Resistant strains of gonorrhea are becoming a major concern. Chancroid should be considered in the differential diagnosis of genital ulcer disease. The possiblility of human immunodeficiency virus infection should be discussed with all these patients.

Before departure: advising tropical travellers

Advising travellers to tropical and subtropical countries before their departure requires physician use of regularly updated information sources. The author outlines an approach to risk assessment and presents an overview of important issues and some information sources.

Travellers' diarrhea

Travellers' diarrhea is reported to affect one-third of those journeying to the tropics. The incidence varies with the destination and risks taken by travellers. Most people are affected by the third day of travel by usually short-lived symptoms. Interest in prevention and treatment reflects the size of the problem and not the severity of the syndrome. Prevention is best achieved by dietary precautions. Prophylactic drugs should be reserved for those likely to suffer most severely or who have the greatest need to avoid symptoms. Treatment should usually be limited to fluid replacement and non-antimicrobial drugs unless circumstances are exceptional.

Chronic fatigue syndrome: review of the literature

Chronic fatigue syndrome, previously known as chronic mononucleosis or post-infectious fatigue, is a poorly understood illness characterized by chronic debilitating fatigue, recurrent flu-like symptoms, and few clinical or laboratory abnormalities. Attention was briefly focused on the Epstein-Barr virus (EBV) as a causal agent, but that hypothesis is now in serious doubt. While a significant incidence of psychiatric illness has been demonstrated among patients with the chronic fatigue syndrome, there is also evidence of subtle immune system abnormalities, leading some researchers to postulate a multi-factorial psycho-immune cause.

Illness in returned travellers

Intercontinental travel is more common now than it has ever been before, and so are travel-related diseases. A thorough history and physical examination provide many clues to possible pathogens, particularly when combined with knowledge of the geographic distribution of specific diseases. Prompt diagnosis and proper treatment are imperative.

Control of influenza: when do I use amantadine?

Influenza causes significant morbidity and mortality in Canada yearly despite the availability of vaccine and the antiviral drug amantadine (Symmetrel®). Vaccine is prepared annually against specific subtypes of influenza A and B that are anticipated to predominate during the winter months. The vaccine should be given in early autumn to patients considered at high risk for the sequelae of influenza. Amantadine, which was first marketed for the treatment of influenza in the early 1960s, is effective in the prevention and early treatment of illness caused by influenza A and is ineffective against influenza B. The drug is available in oral form and should be used as an adjunct to immunization or as an alternative in those for whom immunization is contraindicated or ineffective.

Exchange transfusion in a case of severe Plasmodium falciparum infection: a case report

A 45-year-old Canadian man, who had recently returned from Cameroon, complained of fever lasting eight days. He had 40% parasitemia with Plasmodium falciparum. In spite of oral therapy with chloroquine, quinine, and tetracycline, the patient's condition deteriorated. Although his clinical condition improved more slowly, the patient's parasitemia improved considerably after exchange transfusion and the institution of parenteral quinidine therapy. Exchange transfusion may be life-saving in falciparum malaria and should be instituted early in severe cases.

The Red Ear-drum: To Treat or Not To Treat?

Acute otitis media is typified by the patient with fever, earache, and a "red" ear-drum. Suppurative otitis media, however, often presents without specific symptoms, and redness is the least reliable physical finding. Impaired tympanic membrane mobility on pneumatic otoscopy and bulging and opacification of the ear-drum are more reliable and important physical signs. Review of placebo-controlled trials reveals that antimicrobial therapy produces more rapid relief of fever and earache in patients with the most symptoms. Effects on patients with fewer symptoms are more modest. Amoxicillin remains the standard first-line treatment. Reasonable indications for alternative therapy are reviewed.

Urinary tract infections in female patients

Urinary tract infections are a common problem in female patients. Twenty-five per cent of patients with an initial infection will develop recurrent infections, with reinfection of the urine some time after the urine has been sterilized being the most common situation. Most adult patients have no urinary tract abnormality, with the infecting organism coming from the rectum and colonizing the vagina before colonizing the bladder. In children with urinary tract infections, there is a higher incidence of urinary tract abnormalities. The author presents a plan of management for various clinical problems.

Is there a resurgence of acute rheumatic Fever in Canada?

Recent reports of acute rheumatic fever (ARF) outbreaks in the continental United States have caused alarm. A survey of Canadian pediatric cardiologists was undertaken to determine whether they were aware of an increase in ARF or, more specifically, rheumatic carditis. Ninety per cent of active pediatric cardiologists responded. In 1987, 48 cardiologists reported having seen 48 patients with ARF. Seventy-five per cent of respondents had seen no cases or only one case in the 12 previous months. Seventy-six per cent of respondents had noticed no increase in the number of cases since 1983. The rate of ARF reported by the cardiologists increased from east to west (p = .003), with an overall Canadian rate of 0.19 cases per 100 000 population. Rheumatic carditis and rheumatic fever remain rare. There is no evidence of a Canadian outbreak, but close monitoring is warranted.

Managing sore throat: theory versus practice

The authors address the reliability of clinical impression in the management of sore throat. Five primary care family physicians in rural Ontario examined 222 patients with sore throats. The clinical impression of either Group A β-hemolytic streptococcal (GABHS) or non-GABHS pharyngitis was recorded and throat cultures were ordered in each case. The physicians predicted that 50% of the cultures would be positive for GABHS, whereas only 13.5% actually had positive results. The initial clinical diagnosis of "strep throat" was correct only one in five times. Without cultures, at least 112 patients would have been treated with antibiotics, 87 unnecessarily. The authors conclude that the clinical prediction of GABHS is inaccurate and can lead to unnecessary use of antibiotics.

Human papilloma virus infections

Genital warts are believed to be caused by human papilloma viruses and to be sexually transmitted. The viruses are classified by DNA types, which appear to cause different types of disease. The choice of treatment, and usually its success rate, vary according to the type of disease and its location.

Vaginal infections

Vaginal infections are among the most common complaints for which women see their physicians. The patient complains primarily of vaginal discharge or pruritus. Optimal management of these infections requires a careful history, physical examination, and laboratory assessment to determine the pathogen. Specific therapy is available for the three important causes of vaginal infection: yeast vulvovaginitis, trichomoniasis, and bacterial vaginosis. Concomitant sexually transmitted diseases should be excluded in women with complaints suggestive of vaginal infection.

An audit of adult tetanus immunity

Many Canadian adults are not protected against tetanus. This study examined adult patients' knowledge of their tetanus immunization and its documentation in family practice charts at a downtown teaching community health centre. A date of previous immunization was recalled by 38% (49/129) of patients. Immunization was documented on 34% (44/129) of the "cumulative patient profiles." Of the 22 patients who provided a recall date and whose charts documented immunization, 82% (18/22) had accurate recall. Written immunization records were kept by 19% (25/129) of patients. The results indicate problems both with patients' knowledge of immune status and with chart documentation by physicians. Recommendations for improvement of the immunization process are outlined.

The day-care physical examination

Many Canadian children attend day care. Family physicians are being asked, more and more frequently, to provide assessment of a child's health status prior to day-care admission. The authors of this paper provide evidence for the most useful screening tests in the pre-school age group, outline some means of identification of children at high risk for infectious disease, and suggest rational patterns of use of laboratory investigations. They also propose a guide to the day-care physical examination.

Single-dose therapy of infectious diseases

Single-dose antimicrobial therapy has clear advantages over multiple-dose therapy. Long-acting penicillins have been used for many years in single doses for treatment of streptococcal pharyngitis and early syphilis. More recently, shorter-acting agents are used for non-invasive mucosal infections. In trichomonas vaginitis, for instance, a 2g single dose of metronidazole is approximately 92% effective and is considered the treatment of choice. Controversy still exists about the value of single-dose therapy in women who have bacterial cystitis. However, there is good evidence that 2 or 3 double-strength tablets of co-trimoxazole are very effective and safe in the treatment of uncomplicated cystitis in healthy women.

Update on AIDS for the family physician

Infection with Human Immunodeficiency Virus-I (HIV-I) results in a wide spectrum of clinical disease. Many patients remain clinically well, although they may be infectious to others. These patients may, however, suffer from the psychological effects of knowing they have been infected with the virus. Others may develop symptoms, and many develop fatal opportunistic infections and malignant disease. The primary-care physician must be able to educate, to alleviate fear and misunderstanding, and to provide optimal medical and palliative care.

Binocular visual processing in the owl's telencephalon

Single neurons recorded from the owl's visual Wulst are surprisingly similar to those found in mammalian striate cortex. The receptive fields of Wulst neurons are elaborated, in an apparently hierarchical fashion, from those of their monocular, concentrically organized inputs to produce binocular interneurons with increasingly sophisticated requirements for stimulus orientation, movement and binocular disparity. Output neurons located in the superficial laminae of the Wulst are the most sophisticated of all, with absolute requirements for a combination of stimuli, which include binocular presentation at a particular horizontal binocular disparity, and with no response unless all of the stimulus conditions are satisfied simultaneously. Such neurons have the properties required for 'global stereopsis', including a receptive field size many times larger than their optimal stimulus, which is more closely matched to the receptive fields of the simpler, disparity-selective interneurons. These marked similarities in functional organization between the avian and mammalian systems exist in spite of a number of structural differences which reflect their separate evoluntionary origins. Discussion therefore includes the possibility that there may exist for nervous systems only a very small number of possible solutions, perhaps a unique one, to the problem of stereopsis.