Concerns have arisen anew about possible use of biological weapons. The pathogens considered most likely to be used for this purpose are discussed in this article. A good source for additional information is www.usamriid.army.mil/education/bluebook.html.

The most common cause of travelers' diarrhea, usually a self-limited illness without fever lasting several days, is infection with noninvasive enterotoxigenic (ETEC) or enteroaggregative (EAEC) strains of Escherichia coli. Campylobacter, Shigella, Salmonella, Aeromonas, viruses and parasites are less common.

View the Comparison Table: Antiviral Drugs for Seasonal Influenza for 2025-2026

When the use of aspirin for primary prevention of cardiovascular diseases was last reviewed in The Medical Letter, only one placebo-controlled prospective trial was available: the (male) Physicians' Health Study. Last year, a second large, randomized, placebo-controlled study was reported as part of the Women's Health Study. Recently a sex-specific meta-analysis of 6 trials, including these two, was published.

The injectable direct thrombin inhibitor desirudin (Iprivask – Canyon), a recombinant analog of hirudin, the leech anticoagulant protein, was approved by the FDA in 2003 for prevention of venous thromboembolism (VTE) after elective hip arthroplasty, but was only marketed recently in the US. It has been available in Europe as Revasc for about 10 years. Two other hirudin analogs are available in the US: lepirudin (Refludan) for treatment of heparin-induced thrombocytopenia (HIT) and bivalirudin (Angiomax) for use in percutaneous coronary intervention (PCI).

Persons planning to travel outside the US should be up to date on routine vaccines and, depending on their destination, duration of travel, and planned activities, may also receive certain travel-specific vaccines. Tickborne encephalitis and dengue vaccines, which are not available in the US, are reviewed in a separate article available online. Detailed advice for travel to specific destinations is available from the Centers for Disease Control and Prevention (CDC) at www.cdc.gov/travel/destinations/list. Recommendations for administration of vaccines as part of routine...

The FDA has approved an IV formulation of the antifungal drug posaconazole (Noxafil - Merck) for prophylaxis of Aspergillus and Candida infections in adults at high risk for these infections, such as those with prolonged neutropenia. Posaconazole is also available as delayed-release tablets and an oral suspension.With activity against Aspergillus and Candida, posaconazole has an antifungal spectrum similar to that of voriconazole (Vfend, and generics), but unlike voriconazole it is also active against many species of Mucorales (formerly called Zygomycetes), such as Mucor and Rhizopus....

The drugs of choice for treatment of viral infections (other than HIV) and their dosages are listed in Tables 1-6 on the pages that follow. Some of the indications and dosages recommended here have not been approved by the FDA. Vaccines used for the prevention of viral infections are discussed elsewhere.

Recombinate (Baxter) and Kogenate (Miles), two recombinant-DNA-derived Factor VIII (rFVIII) preparations, were recently approved for marketing by the US Food and Drug Administration. Clotting factor concentrates are generally prepared from large plasma pools obtained from thousands of donors. Without adequate inactivation of viruses, these concentrates can transmit hepatitis B, hepatitis C, and the human immunodeficiency virus (HIV), among others. The new recombinant products, which include human albumin added as a stabilizer, are claimed to be free of blood-borne viruses.

Zanamivir, a neuraminidase inhibitor taken by inhalation, has been approved by the FDA for treatment of influenza. Oseltamivir phosphate, an oral neuraminidase inhibitor, will probably be approved soon.