Abstract. Hepatitis E is an important medical pathogen in many developing countries but is rarely reported from the United States, although antibody to hepatitis E virus (anti-HEV) is found in Ͼ 1% of U.S. citizens. Zoonotic spread of the virus is suspected. Sera obtained from 239 wild rats trapped in widely separated regions of the United States were tested for anti-HEV. Seventy-seven percent of rats from Maryland, 90% from Hawaii, and 44% from Louisiana were seropositive for anti-HEV. Rats from urban as well as rural areas were seropositive and the prevalence of anti-HEV IgG increased in parallel with the estimated age of the rats, leading to speculation that they might be involved in the puzzling high prevalence of anti-HEV among some U.S. city dwellers. The discovery of anti-HEV in rats in the United States and the recently reported discovery that HEV is endemic in U.S. swine raise many questions about transmission, reservoirs, and strains of HEV in developed countries.Hepatitis E is the first or second most important cause of acute clinical hepatitis in many developing countries of Asia, the Middle East and North Africa. Hepatitis E can occur sporadically or in epidemics and the peak clinical attack rate usually occurs in young adults. 1 Hepatitis E is caused by hepatitis E virus (HEV), an unclassified virus that is enterically transmitted. Antibody to HEV (anti-HEV), indicative of past infection, has been detected in only 5-60% of the general population of developing countries where the disease is endemic. 2 The peak age-specific acquisition of anti-HEV occurs in young adults. 3 The relatively low prevalence of antibody in young children and the relatively late acquisition of infection in some populations are unusual patterns for a virus that is believed to be transmitted principally by the fecal-oral route. Although this pattern is consistent with a cohort effect, studies from India suggest that this is not the explanation. 3 In industrialized countries, clinical hepatitis E is rarely reported and the few cases that do occur are generally among individuals who acquired their infection in a developing country. 4,5 It is therefore perplexing that anti-HEV has been detected in these industrialized countries in 0.4-5% of healthy populations (generally blood donors), even in the absence of known risk factors. 6 In some studies, even higher prevalences of anti-HEV have been found in specific populations in the United States. 7,8 Although the specificity of some tests used for measuring anti-HEV has been questioned, it is unlikely that false-positive results can explain the relatively high prevalence of anti-HEV in populations with no significant clinical hepatitis E.It has been proposed that animal reservoirs of HEV exist in some regions and that human infections may represent, in part, a zoonosis. The successful transmission of HEV to swine, rats, and sheep in the former USSR and in Asia has been reported, as has the transmission of HEV to several non-human primate species. 9-14 Antibody to HEV has been detect...

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Leptospirosis is a major public health problem throughout the world. Clinical recognition of leptospirosis is challenging, and the definitive serologic diagnostic assay, the microscopic agglutination test, is timeconsuming and difficult to conduct. Various serologic screening tests have been developed, but their performance among ill persons in the United States has not been established. Eight screening tests were compared using 379 serum samples obtained in 1998 and 1999 from a series of 236 patients (33 with confirmed infection). The median number of days between illness onset and specimen collection was 9. The overall sensitivity, by specimen, for each test was as follows: indirect hemagglutination assay (MRL Diagnostics, Cypress, Calif.), 29%; INDX Leptospira Dip-S-Tick (PanBio InDx, Inc., Baltimore, Md.), 52%; Biognost IgM IFA test (Bios GmbH Labordiagnostik, Gräfelfing, Germany), 40%; Biolisa IgM ELISA (Bios GmbH, Labordiagnostik), 48%; Leptospira IgM ELISA (PanBio Pty Ltd., Brisbane, Australia), 36%; SERION ELISA classic Leptospira (Institut Virion•Serion GmbH, Würzburg, Germany), 48%; LEPTO Dipstick(Organon-Teknika, Ltd., Amsterdam, The Netherlands), 34%; Biosave latex agglutination test (LATEX; Bios GmbH Labordiagnostik), 86%. Test specificity ranged from 85 to 100% among all tests except LATEX, for which the specificity was significantly lower, at 10%. Test sensitivity was particularly low (<25%) for all tests (except LATEX) on specimens collected during the first week of illness. This is the most comprehensive field trial of leptospirosis screening tests reported to date. The data indicate that immunoglobulin M detection tests have limited utility for diagnosing leptospirosis during the initial evaluation of patients seen in Hawaii, a time when important therapeutic decisions are made. Improved leptospirosis screening tests are needed.

From 1991 through 1997, few gonococcal strains exhibiting intermediate or clinically significant resistance to CDC-recommended doses of fluoroquinolones were identified from Hawaii. Isolates belonged to a large number of phenotypic and genotypic types, suggesting that most cases were imported, with only a few instances in which isolate pairs indicated that secondary transmission of infections had occurred in Hawaii. Beginning in 1998, the number of CipR isolates increased markedly, and more isolates belonged to fewer phenotypic and genotypic types, suggesting either more frequent importation of fewer strain types or the possibility that the endemic spread of a few strains is beginning to occur.