Infectious Diseases

Disclaimer: While every attempt is made to ensure that drug dosages provided within the text of this journal and the website are accurate, readers are urged to check drug package inserts before prescribing. Views and opinions in this publication and the website are not necessarily endorsed by or reflective of those of the publisher.

Susan L. Eldred, RN, BScN, MBA, PhD candidate, University of Ottawa, Ottawa, ON.
Wendy A. Gifford, RN, PhD candidate, University of Ottawa, Ottawa, ON.

HIV/AIDS is rapidly increasing among adults age 50 and older. However, limited research has been conducted to understand the issues associated with HIV/AIDS in advancing age. This paper describes issues related to the transmission and contraction of HIV/AIDS among older adults, their complex clinical picture, and management of antiretroviral therapy, as well as social considerations. Cognizance of polypharmacy and comorbidities common with advanced age as well as the double stigmatization of age and HIV/AIDS is essential. Further research is needed to better understand the interactions between HIV/AIDS and age, and to determine effective, safe treatments and appropriate highly active antiretroviral therapy dosing in older adults.
Key words: HIV, AIDS, sexually transmitted diseases, older adults, highly active antiretroviral therapy.

Roger E.Thomas,MD, Ph.D., CCFP, MRCGP, Professor, Department of Family Medicine, University of Calgary, and Cochrane Coordinator, University of Calgary, Calgary, AB.

Recent evidence has shown that vaccination against influenza is effective in reducing the complications of influenza (pneumonia, hospitalization for influenza or pneumonia, and deaths due to influenza or pneumonia) for those 60 years and over living in long-term care facilities (LTCs) during periods of high viral circulation if the vaccine has a good match to the circulating strain. Vaccination was found to be similarly effective for those 60 and over living in the community. There is further evidence that health care workers should be vaccinated for their own benefit, as vaccination is demonstrably effective for healthy adults under 60, and most health professionals are under 60.There is some evidence that vaccination of these workers may provide additional protection for residents of LTCs from the complications of influenza. Influenza can be detected by rapid office-based tests and should be used when the pretest probability of influenza is less than 30%. The evidence suggests that oseltamivir and zanamivir are effective in reducing the symptoms of cases and reducing infections in households and contacts of cases.
Keywords: influenza, older adults, vaccination, prevention of influenza, antivirals.

To the Editor:
The omission of Dukoral™* (oral, inactivated traveller’s diarrhoea and cholera vaccine) from Dr. Patrice Bourée’s article “Safe Foreign Travel” (Geriatrics & Aging 2006;7:472-8) was surprising, especially since the author comments that “traveller’s diarrhea occurs in up to 50% of travellers in tropical areas.”
Could the author comment?

K.M. Laycock

Dr. Patrice Bourée responds:
The reader’s question is not surprising for me. I have not forgotten the matter of vaccination with Dukoral™. I am familiar with this vaccine, manufactured by SBL Vaccin AB (Stockholm) with Vibrio cholerae 01, killed by heat or formol and B-subunit choleric toxin. But, according to the French Health Ministry, the official recommendations are “such a vaccination is not justified for travellers who wash their hands and practice adequate personal hygiene. It is only justified for health teams who are working in a cholera-infected area or in a refugee’s camp.”¹ This does not apply to the typical older traveller. Travellers should be attentive to the risk of acquiring cholera, but the risk is very low for most travellers who do not encounter conditions of severe poverty. The fear of this disease is used to promote food safety.² Besides, “the effectiveness of such a vaccine is not proved in people of 65 years old and more.”¹ So, my failure to mention it is not an omission but my estimation that this vaccine is not recommended for older adults.

However, the indications for this drug pose an interesting problem that is not yet satisfactorily resolved. Opinions differ markedly in Europe, Canada, and in the United States on the matter of this and other agents, and it is difficult to say which perspective is best. There is a similar conflict regarding agents used to treat traveller’s diarrhea: in the U.S., bismuth subsalicylate is used as first-line therapy, while this agent is strictly forbidden in France and is not available.

Sincerely yours,
Dr. Patrice Bourée

*Note: Dukoral was approved for use in Canada in 2003. It is indicated for active immunization against disease caused by Vibrio cholerae serogroup O1 in adults and children from two years of age who will be visiting endemic/epidemic areas.

Comité Technique des Vaccinations. Guide des vaccinations. INPES, Paris, 2006, 125-9.
DuPont HL, Steffen R. Textbook of Travel Medicine. BC Decker: Hamilton, Ontario, 1997: 86-91.

Patrice Bourée, MD, Head of the Department of Tropical Medicine, Bicetre Hospital (AP-HP); Paris-XI University, Paris, France.

The older population continues to increase; these individuals generally have substantial leisure time and are in good mental and physical health. As a result, they take the opportunity to travel. To avoid unnecessary risks, trips should be carefully planned with regard to updating immunizations according to the destination. Some older individuals suffer from chronic diseases which, though not a contraindication to travel, should be considered. Their medication should be reviewed with regard to the climate; there may be a need for specific travel medication such as chemoprophylaxis of malaria. It may be necessary to seek the advice of different specialists related to the patient’s medical problem. With careful planning, older adults shall remember only the pleasant moments of the trip.
Key words: immunization, travel, older adults, infectious disease, advice.

Michael A. Drebot, PhD, Chief, Viral Zoonoses, Zoonotic Diseases and Special Pathogens, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada.
Harvey Artsob, PhD, Director, Zoonotic Diseases and Special Pathogens, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada.

Since its introduction into North America in 1999, West Nile virus (WNV) has rapidly expanded its range across the continent. There is evidence that it has moved into the Caribbean and South and Central America. The virus has significantly affected public health, causing more than 20,000 cases of associated illness and resulting in the largest WNV epidemic ever recorded. Although neuroinvasive disease occurs in less than 1% of infections, the risk for encephalitis and other neurological illnesses increases with age. Currently there is no specific therapy for the treatment of WNV-associated disease and a vaccine is not yet available. Decreasing the risk of virus exposure requires seasonal preventative and control measures.
Key Words: West Nile virus, epidemiology, diagnosis, neurological illness, disease prevention.

Chamandeep Thind, MRCP, Department of Dermatology, Aberdeen Royal Infirmary, Aberdeen, Scotland, UK.
Simone Laube, MD MRCP, Department of Dermatology, Aberdeen Royal Infirmary, Aberdeen, Scotland, UK.

Skin and soft tissue infections are an important cause of morbidity and mortality in older adults. Decreased immunity, changes in skin anatomy, and comorbidities contribute to an increased susceptibility to infections. Methicillin-resistant Staphylococcus aureus is an increasingly common problem in both the community as well as hospitals. Clinical features and management of some common skin infections encountered in this population are reviewed here. Local microbiological guidelines and drug susceptibilities should be taken into account in the treatment.
Key words: bacterial skin infections, cellulitis, MRSA, fungal infection, scabies.

In the early days of antibiotic therapy, clinicians started predicting the end of the plague of infectious diseases that had beset humankind for its entire history. Of course, medical science was completely wrong. We did not count on the adaptability of microorganisms, the medical interventions that increase immune deficiency, the global transmission of pathogens, and many other confounding difficulties. Most importantly, we forgot that the background microbial flora within which we live is essential for our survival, and that the prevention of illnesses from these pathogens is more dependent on broad public health measures (sanitation, water purification, nutrition) than the use of antibiotics in specifically affected individuals, even though antibiotic use is life-saving in certain circumstances. Notably, we are seeing more unusual infections in older people who are not immunosuppressed, and the reasons for this are quite simple. The population is aging, and older adults travel to unusual places. Novel infections are often transported to our country in a variety of ways.

Our CME article with this edition’s focus is ”Common Skin Infections in the Older Adult” by Chamandeep Thind and Dr. Simone Laube. The article ”West Nile Virus: A Pathogen of Concern for Older Adults,” by Drs. Michael A. Drebot and Harvey Artsob, reviews a disease that is new to Canada and has had a substantial impact on the health of older Canadians. It has certainly changed the summertime habits of many Canadians of all ages. Several travel companies now specialize in adventure travel for older adults, and if your patients are among those adventurous seniors, you will appreciate Dr. Patrice Bourée’s article ”Safe Foreign Travel for the Older Adult.”

We have our usual columns featuring articles on other topics. Our Cardiovascular column this month is “The Role of Revascularization in Older Patients with Acute Coronary Syndromes” by Anna J.M. van de Sande, Dr. Paul W. Armstrong, and Dr. Padma Kaul. Our skin article is entitled ”Nonmalignant Photo Damage” by Drs. Joseph F. Coffey and Gordon E. Searles. Ever since the APOE 4 allele, involved in lipoprotein metabolism, was discovered to have a relationship to Alzheimer’s disease, hypotheses as to the relationship of cholesterol and dementia have been explored. For those interested in cognitive impairment, the article ”Is Cholesterol a Memory Thief?“ by Dr. D. Larry Sparks, will be particularly interesting. Our Cancer column features the second part of Patricia K. Long and Dr. David Ollila’s article entitled “Cutaneous Melanoma, Part Two: Management of Patients with Biopsy-Proven Melanoma.” Neuropathic foot ulcers are a serious issue for diabetic older adults, and Drs. Timothy Daniels and Evan Timir review “Surgical Treatment of Diabetic Foot Complications.” As well, this issue features a book review, ”Evidence-Based Medicine Guidelines” by Meteb Al-Foheidi.

Enjoy this issue,
Barry Goldlist

Janet E. McElhaney, MD, FRCPC, FACP, Geriatrician, Center for Immunotherapy of Cancer and Infectious Diseases and UConn Center on Aging, University of Connecticut School of Medicine, Farmington, CT, USA.

Influenza is a serious illness and is probably the single cause of excess mortality during the winter months in the portion of the population that is aged 65 and over. In spite of its limited efficacy in older adults, influenza vaccination is a cost-saving medical intervention that can help to prevent pneumonias, exacerbations of heart failure, and, surprisingly, heart attacks and strokes. As hospitalization rates for acute respiratory illnesses continue to rise in spite of widespread vaccination programs, antiviral drugs need to be incorporated into prophylaxis and early treatment strategies for influenza. Particularly in the institutional setting, seasonal prophylaxis or influenza outbreak control that involves the staff is essential.

Key words: influenza, antiviral drugs, vaccination, prophylaxis, drug resistance.

Richard Long, MD, Professor, Department of Medicine, University of Alberta, Edmonton, AB; Chairman, Tuberculosis Committee, Canadian Thoracic Society.

The incidence of tuberculosis increases with age in Canadians. The prevalence of latent tuberculosis infection (LTBI) may also increase with age in Canadians, though information on the age distribution of LTBI is less precise. Chronic inflammatory conditions that currently constitute the major indications for new biologic therapies (tumour necrosis factor inhibitors), such as Crohn's disease and rheumatoid arthritis, often have an older age onset. Biologic therapies have the potential to cause LTBI to progress to active tuberculosis disease. Their use in older Canadians or other populations that may have a higher than average prevalence of LTBI poses a challenge to tuberculosis control.
Key words: tuberculosis, tumour necrosis factor inhibitors, age, rheumatoid arthritis, Crohn's disease.

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Infectious Disease Applications for Handheld Computers

Philippe L. Bedard, MD, and Feisal A. Adatia, MD, MSc, First Year Ophthalmology Resident; University of Toronto, Toronto, ON.

Many health care professionals use handheld computers to access medical reference information and drug databases at the point of care.¹There are many specific infectious disease software applications for handheld computers, which combine information regarding specific microbial pathogens and sites of infections with antimicrobial databases and treatment guidelines. Infectious disease software may minimize medication prescription errors and promote more rational use of antimicrobials. This article briefly reviews the salient features of five popular infectious disease applications.

ePocrates ID
ePocrates ID is available with ePocrates Rx Pro, the purchase-based suite which includes the popular handheld drug database, ePocrates Rx. Users can search by location, bug or drug. ePocrates ID provides a numbered list of recommended antimicrobial regimens for both empiric and specific pathogen-based therapy. For each antimicrobial, users can tap on a hyperlink to be connected with ePocrates Rx for more detailed drug monographs. ePocrates ID offers the simplest and most intuitive interface of any available infectious disease handheld application. Busy clinicians can quickly find treatment recommendations and a wide range of well-organized antimicrobial information at the point of care. However, users should be aware that the manufacturer of ePocrates has the ability to track how information is accessed on ePocrates ID.² Another drawback is that ePocrates cannot be run from an expansion memory card. ePocrates Rx Pro is expensive and users must renew their subscription annually. Unlike the core drug database in ePocrates Rx, ePocrates ID is not automatically updated with each hotsync operation, although users can download quarterly updates.

The Sanford 2003 Guide to Antimicrobial Therapy
The Sanford Guide is the handheld version of the popular paper-based infectious disease handbook. The opening screen of the handheld version is split into a "rapid reference" section of 17 commonly used tables and a searchable alphabetical index. The Sanford Guide provides the most detailed coverage of antimicrobial spectra, adverse medication effects and drug interactions and the most extensive literature references. However, unlike other applications, the information in the Sanford Guide is not organized by individual drug monographs, making it difficult to find information about a particular antimicrobial or clinical infection quickly. The search feature in the Sanford Guide is also cumbersome, as scroll bars must be used extensively to find information.

Johns Hopkins Division of Infectious Diseases Antibiotic Guide
Information in this guide may be searched through three side tabs entitled diagnosis, pathogen or antibiotic. Of the reviewed programs, this is the only one which is free and that automatically updates when a handheld syncs with a desktop computer. While being quite comprehensive and having undergone vigorous review for accuracy, this program does not provide any pediatric dosing. As well, drug monographs cannot be accessed through diagnosis or pathogen tabs, adding time required to search for drug details.

The 5-Minute Infectious Diseases Consult
This program is one of the extensive catalogues of medical reference books available from Skyscape. For users of other Skyscape references, the link feature allowing cross-referencing of databases is an attractive benefit. There are four indices that can be searched: Main Index, Microorganisms, Medication Index and Table of Contents. The Main Index is organized into basics, clinical manifestations, diagnosis, treatment, follow-up and selected readings. Perhaps the best feature of this program is its speed and ease of navigation. It is the most expensive of the reviewed databases and provides less drug monograph information than the other alternatives.

Infectious Diseases and Antimicrobials Notes
This program is formatted to run in iSilo, an e-book reader. It has the following sections: antimicrobial spectra index, prophylactic therapy, normal flora, organisms and treatment, infectious disease and treatment and antimicrobial treatment. This program has several attractive features. Its prophylactic therapy section provides details on prevention of infection with chemotherapy and provides surgical antibiotic prophylaxis notes. Its inclusion of a normal flora section is also quite educational. However, it requires extensive scrolling and lacks sidebar tabs seen in other applications. Furthermore, it does not disclose author information or provide references for its citations.

Conclusion
There is a variety of alternatives for users in search of an infectious disease reference for their handheld computers. ePocrates ID and Johns Hopkins Division of Infectious Diseases Antibiotic Guide provide the most concise and easily navigable treatment guidelines for particular clinical scenarios. The Sanford 2003 Guide to Antimicrobial Therapy may be most appropriate for specialists well acquainted with the paper-based version of the guide. The 5-Minute Infectious Diseases Consult offers the most extensive diagnostic information and can be linked with other Skyscape applications. Finally, the Infectious Diseases and Antimicrobials Notes may appeal to those in search of information regarding microbial flora and antimicrobial prophylaxis.

References

Adatia FA and Bedard PL. "Palm reading": 1. Handheld hardware and operating systems. CMAJ 2002;167:775-80.

Adatia FA and Bedard PL. "Palm reading": 2. Handheld software for physicians. CMAJ 2003;168:727-34.

Miller SM, Beattie MM, Butt AA. Personal digital assistant infectious diseases applications for health care professionals. Clin Infect Dis 2003;36:1018-29.

Related Terms: Infectious Diseases, handheld computers, infectious disease applications, technology

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