Long-distance transport of pathogens plays a critical role in the emergence of novel diseases. Shipping is a major contributor to such transport, and the role of ships in spreading disease has been recognized for centuries. However, statistical confirmation of pathogen spread by shipping is usually impractical. We present evidence of invasive spread of infectious salmon anemia in the salmon farms of Scotland and demonstrate a link between vessel visits and farm contamination. The link is associated with vessels moving fish between sites and transporting harvest, but not with vessels delivering food or involved in other work.

We modeled surface wetness at high resolution, using a dynamic hydrology model, to predict flood and swamp water mosquito abundances. Historical meteorologic data, as well as topographic, soil, and vegetation data, were used to model surface wetness and identify potential fresh and swamp water breeding habitats in two northern New Jersey watersheds. Surface wetness was positively associated with the subsequent abundance of the dominant floodwater mosquito species, Aedes vexans, and the swamp water species, Anopheles walkeri. The subsequent abundance of Culex pipiens, a species that breeds in polluted, eutrophic waters, was negatively correlated with local modeled surface wetness. These associations permit real-time monitoring and forecasting of these floodwater and nonfloodwater species at high spatial and temporal resolution. These predictions will enable public health agencies to institute control measures before the mosquitoes emerge as adults, when their role as transmitters of disease comes into play.

In June 1999, the dioxin crisis, caused by dioxin-contaminated feed components, exploded in Belgium, resulting in withdrawal of chicken and eggs from the market. Through the sentinel surveillance system, a decrease in Campylobacter infections during June 1999 was noticed. A model was generated with the reports from preceding years (1994 to 1998), and a prediction of the number of infections in 1999 was calculated. The model shows a significant decline (40%) in the number of infections, mainly because of the withdrawal of poultry. The use of a disaster as an epidemiologic tool offers a unique opportunity to observe exceptional changes in the occurrence of infections or other diseases.

Beginning with the 1999-2000 influenza season, physicians throughout Hawaii ordering a viral culture for patients with suspected influenza were also offered influenza rapid testing. We compared the number of viral respiratory cultures sent to the Hawaii Department of Health and the number of providers who participated in influenza surveillance over consecutive influenza seasons. The number of viral respiratory cultures rose from 396 to 2,169 between the 1998-1999 and 2000-2001 influenza seasons, and the number of providers submitting >1 influenza culture increased from 34 to 327, respectively. The number of influenza isolates obtained each season also increased (from 64 to 491). The available data suggest that the changes observed in Hawaii’s influenza surveillance were not secondary to differences in influenza activity between seasons. This is the first evaluation of integrating influenza rapid testing into public health surveillance. Coupling rapid tests with cultures appears to be an effective means of improving influenza surveillance.

We conducted a randomized, triple-blinded home drinking water intervention trial to determine if a large study could be undertaken while successfully blinding participants. Households were randomized 50:50 to use externally identical active or sham treatment devices. We measured the effectiveness of blinding of participants by using a published blinding index in which values >0.5 indicate successful blinding. The principal health outcome measured was “highly credible gastrointestinal illness” (HCGI). Participants (n=236) from 77 households were successfully blinded to their treatment assignment. At the end of the study, the blinding index was 0.64 (95% confidence interval 0.51-0.78). There were 103 episodes of HCGI during 10,790 person-days at risk in the sham group and 82 episodes during 11,380 person-days at risk in the active treatment group. The incidence rate ratio of disease (adjusted for the clustered sampling) was 1.32 (95% CI 0.75, 2.33) and the attributable risk was 0.24 (95% CI -0.33, 0.57). These data confirm that participants can be successfully blinded to treatment group assignment during a randomized trial of an in-home drinking water intervention.

Pulsed-field gel electrophoresis (PFGE) of Bordetella pertussis chromosomal DNA fragments generated by XbaI restriction has been used to subtype isolates for epidemiologic studies. To better understand the natural history of pertussis, we determined the PFGE profiles of 1,333 strains isolated in the United States from 1935 to 1999. Results showed a shift in prevalent profiles from the earliest to the latest study periods. In addition, genetic diversity decreased over time, and prevalent profiles were more highly related to each other than to less common profiles. These results provide the foundation for investigating the impact of prevention strategies, including the use of the acellular vaccines, on the currently circulating B. pertussis population.

We report the genetic characterization of the M RNA segment of Crimean Congo hemorrhagic fever virus (CCHFV). Two CCHFV strains isolated in Xinjiang Province, a region endemic for CCHF in northwestern China, were studied. These strains, designated BA66019 and BA8402, were isolated in 1965 and 1984 from a CCHF patient and Hyalomma ticks, respectively. Viral RNA was extracted from suckling mouse brains infected with these two strains, amplified, and sequenced. The full-length M RNA, consisting of 5.3 kb, was determined for both strains. The coding nucleotide sequences of the two strains differed from each other by 17.5% and from the reference CCHFV strain IbAr10200 by a mean of 22%, suggesting that the genus Nairovirus comprises a group of genetically highly diverse strains.

To determine the distribution and antimicrobial drug resistance in bacterial pathogens causing nosocomial infections, surveillance data on nosocomial infections documented from 1981 to 1999 at National Taiwan University Hospital were analyzed. During this period, 35,580 bacterial pathogens causing nosocomial infections were identified. Candida species increased considerably, ranking first by 1999 in the incidence of pathogens causing all nosocomial infections, followed by Staphylococcus aureus and Pseudomonas aeruginosa. Candida species also increased in importance as bloodstream infection isolates, from 1.0% in 1981-1986 to 16.2% in 1999. The most frequent isolates from urinary tract infections were Candida species (23.6%), followed by Escherichia coli (18.6%) and P. aeruginosa (11.0%). P. aeruginosa remained the most frequent isolates for respiratory tract and surgical site infections in the past 13 years. A remarkable increase in incidence was found in methicillin-resistant S. aureus (from 4.3% in 1981-1986 to 58.9% in 1993-1998), cefotaxime-resistant E. coli (from 0% in 1981-1986 to 6.1% in 1993-1998), and cefotaxime-resistant Klebsiella pneumoniae (from 4.0% in 1981-1986 to 25.8% in 1993-1998). Etiologic shifts in nosocomial infections and an upsurge of antimicrobial resistance among these pathogens, particularly those isolated from intensive care units, are impressive and alarming.

A large outbreak of tularemia occurred in Kosovo in the early postwar period, 1999-2000. Epidemiologic and environmental investigations were conducted to identify sources of infection, modes of transmission, and household risk factors. Case and control status was verified by enzyme-linked immunosorbent assay, Western blot, and microagglutination assay. A total of 327 serologically confirmed cases of tularemia pharyngitis and cervical lymphadenitis were identified in 21 of 29 Kosovo municipalities. Matched analysis of 46 case households and 76 control households suggested that infection was transmitted through contaminated food or water and that the source of infection was rodents. Environmental circumstances in war-torn Kosovo led to epizootic rodent tularemia and its spread to resettled rural populations living under circumstances of substandard housing, hygiene, and sanitation.

We investigated the prevalence of Shiga toxin-producing Escherichia coli (STEC) in hospitalized diarrhea patients in Calcutta, India, as well as in healthy domestic cattle and raw beef samples collected from the city's abattoir. Multiplex polymerase chain reaction using primers specific for stx1 and stx2 detected STEC in 18% of cow stool samples, 50% of raw beef samples, and 1.4% and 0.6% of bloody and watery stool samples, respectively, from hospitalized diarrhea patients. Various virulence genes in the STEC isolates indicated that stx1 allele predominated. Plasmid-borne markers, namely, hlyA, katP, espP, and etpD, were also identified. Bead enzyme-linked immunosorbent assay and Vero cell assay were performed to detect and evaluate the cytotoxic effect of the Shiga toxins produced by the strains. STEC is not an important cause of diarrhea in India; however, its presence in domestic cattle and beef samples suggests that this enteropathogen may become a major public health problem in the future.

In 1999, an outbreak of Legionnaires' disease affected many visitors to a flower show in the Netherlands. To identify the source of the outbreak, we performed an environmental investigation, as well as a case-control study among visitors and a serologic cohort study among exhibitors to measure exposure to possible sources. Of 77,061 visitors, 188 became ill (133 confirmed and 55 probable cases), for an attack rate of 0.23% for visitors and 0.61% for exhibitors. Two whirlpool spas in halls 3 and 4 of the exhibition and a sprinkler in hall 8 were culture positive for Legionella pneumophila. One of three genotypes found in both whirlpool spas was identical to the isolates from 28 of 29 culture-positive patients. Persons who paused at the whirlpool spa in hall 3 were at increased risk for becoming ill. This study illustrates that whirlpool spas may be an important health hazard if disinfection fails.

Two returning safari tourists with African trypanosomiasis were admitted to the Hospital for Tropical Diseases, London, in a 3-day period, compared with six cases in the previous 14 years. We describe the clinical features, diagnosis, and problems encountered in accessing appropriate therapy, and discuss the potential for emergence of this disease in increasingly adventurous international travelers.

We studied a cohort of patients requiring renal dialysis who had migrated to the United Kingdom from tuberculosis (TB)-endemic countries and found extremely high rates of TB (1,187 cases per 100,000 per year), partly associated with end-stage diabetic renal disease. We recommend enhanced vigilance and screening of such patients, both to reduce illness and death and to prevent nosocomial spread of TB among susceptible persons.

The first human rabies case in Chile since 1972 occurred in March 1996 in a patient without history of known exposure. Antigenic and genetic characterization of the rabies isolate indicated that its reservoir was the insectivorous bat Tadarida brasiliensis. This is the first human rabies case caused by an insectivorous bat rabies virus variant reported in Latin America.

Infections with methicillin-resistant Staphylococcus aureus (MRSA) are increasingly community acquired. We investigated an outbreak in which a food handler, food specimen, and three ill patrons were culture positive for the same toxin-producing strain of MRSA. This is the first report of an outbreak of gastrointestinal illness caused by community-acquired MRSA.

An infection with Cryptosporidium felis in an HIV-positive man from Italy was successfully treated with paromomycin, despite the patient’s having a CD4+ cell count of 31/mL. Fourteen cases of human infection with C. felis have been described, all in the past 3 years, emphasizing the public health importance of Cryptosporidium parasites other than C. parvum.

Virus-associated hemophagocytic syndrome is a fulminant disorder associated with systemic viral infection and characterized pathologically by multiple-organ infiltration of hemophagocytic histiocytes into the lymphoreticular tissues. This is the first report of a previously healthy adult in whom Human herpesvirus 6 reactivation induced this syndrome with severe hemodynamic and respiratory distress.

Rickettsia felis, formerly called ELB agent, was identified by using molecular biology techniques in the cat flea (Ctenocephalides felis felis) from southwestern Spain. For the first time this flea-transmitted rickettsia has been detected within its vector in Eurasia.

Enterobacteria contribute to two serious clinical syndromes seen in African AIDS patients: diarrhea and septicemia. In West Africa, prophylaxis with sulfamethoxazole-trimethoprim (SXT) reduced illnesses. We report reduced sensitivity of enterobacteria to available antimicrobial agents in Zambia, with only 22% of nontyphoidal salmonellae and 6% of shigellae sensitive to SXT.

Mycoplasma contamination of the licensed anthrax vaccine administered to military personnel has been suggested as a possible cause of Persian Gulf illness. Vaccine samples tested by nonmilitary laboratories were negative for viable mycoplasma and mycoplasma DNA and did not support its survival. Mycoplasma contamination of anthrax vaccine should not be considered a possible cause of illness.

The nondiphtheriae corynebacteria are uncommon but increasingly recognized as important agents of community-acquired endocarditis in patients with underlying structural heart disease, as well as of prosthetic-valve endocarditis. We describe three cases of nondiphtheriae corynebacterial endocarditis, including the first reported case of endocarditis caused by Corynebacterium amycolatum, occurring over an 18-month period, all in association with indwelling intravascular devices.

Two diabetic patients with primary liver abscess, who initially responded unsatisfactorily to intravenous ceftriaxone or cefoxitin treatment and had abscess drainage, were found to be infected with a single clone of Klebsiella pneumoniae with two different colonial morphotypes and resistotypes. Primary liver abscess caused by second-generation cephalosporin-resistant K. pneumoniae strains may be an emerging problem in Taiwan.