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In October 2001, the first inhalational anthrax case in the United States since 1976 was identified in a media company worker in Florida. A national investigation was initiated to identify additional cases and determine possible exposures to Bacillus anthracis. Surveillance was enhanced through health-care facilities, laboratories, and other means to identify cases, which were defined as clinically compatible illness with laboratory-confirmed B. anthracis infection. From October 4 to November 20, 2001, 22 cases of anthrax (11 inhalational, 11 cutaneous) were identified; 5 of the inhalational cases were fatal. Twenty (91%) case-patients were either mail handlers or were exposed to worksites where contaminated mail was processed or received. B. anthracis isolates from four powder-containing envelopes, 17 specimens from patients, and 106 environmental samples were indistinguishable by molecular subtyping. Illness and death occurred not only at targeted worksites, but also along the path of mail and in other settings. Continued vigilance for cases is needed among health-care providers and members of the public health and law enforcement communities.

New meningococcal vaccines are undergoing clinical trials, and changes in the epidemiologic features of meningococcal disease will affect their use. Active laboratory-based, population-based US surveillance for meningococcal disease during 1992-1996 was used to project that 2400 cases of meningococcal disease occurred annually. Incidence was highest in infants; however, 32% of cases occurred in persons >/=30 years of age. Serogroup C caused 35% of cases; serogroup B, 32%; and serogroup Y, 26%. Increasing age (relative risk [RR], 1.01 per year), having an isolate obtained from blood (RR, 4.5), and serogroup C (RR, 1.6) were associated with increased case fatality. Among serogroup B isolates, the most commonly expressed serosubtype was P1.15; 68% of isolates expressed 1 of the 6 most common serosubtypes. Compared with cases occurring in previous years, recent cases are more likely to be caused by serogroup Y and to occur among older age groups. Ongoing surveillance is necessary to determine the stability of serogroup and serosubtype distribution.

In 2000, >400 cases of disease caused by Neisseria meningitidis serogroup W135 (MenW135), the largest MenW135 outbreak reported to date, occurred worldwide among Hajj pilgrims and their contacts. To elucidate the origin of the outbreak strains and to investigate their relatedness to major clonal groups, genotypic and phenotypic subtyping was performed on 26 MenW135 outbreak-associated isolates and 50 MenW135 isolates collected worldwide from 1970 through 2000. All outbreak-associated isolates were members of a single clone of the hypervirulent electrophoretic type (ET)-37 complex, designated the "(W)ET-37 clone"; 19 additional MenW135 strains were also members of this clone, and the remaining 31 MenW135 strains were clearly distinct. The 2000 MenW135 outbreak was not caused by emergence of a new MenW135 strain but rather by expansion of the (W)ET-37 clone that has been in circulation at least since 1970; the strains most closely related to those causing the 2000 outbreak have been isolated in Algeria, Mali, and The Gambia in the 1990s.

Adventure travel is becoming more popular, increasing the likelihood of contact with unusual pathogens. We investigated an outbreak of leptospirosis in “Eco-Challenge” multisport race athletes to determine illness etiology and implement public health measures. Of 304 athletes, we contacted 189 (62%) from the United States and 26 other countries. Eighty (42%) athletes met our case definition. Twenty-nine (36%) case-patients were hospitalized; none died. Logistic regression showed swimming in the Segama River (relative risk [RR]=2.0; 95% confidence interval [CI]=1.3 to 3.1) to be an independent risk factor. Twenty-six (68%) of 38 case-patients tested positive for leptospiral antibodies. Taking doxycycline before or during the race was protective (RR=0.4, 95% CI=0.2 to 1.2) for the 20 athletes who reported using it. Increased adventure travel may lead to more frequent exposure to leptospires, and preexposure chemoprophylaxis for leptospirosis (200 mg oral doxycycline/week) may decrease illness risk. Efforts are needed to inform adventure travel participants of unique infections such as leptospirosis.

Surveillance for coccidioidomycosis (CM) and a case-control study for risk factors among adults were conducted in Kern County, California. From January 1995 through December 1996, 905 cases of CM were identified, for an annual incidence of 86 cases per 100,000 population. A total of 380 adults were enrolled in the case-control study: 77 had severe pulmonary disease, 33 had disseminated disease, and 270 control patients had mild disease. Independent risk factors for severe pulmonary disease included diabetes, recent history of cigarette smoking, income of < $15,000 per year, and older age. Oral antifungal therapy before hospitalization was associated with a reduced risk of CM pneumonia. Risk factors for disseminated disease were black race, income of < $15,000 per year, and pregnancy. Early treatment of CM with oral antifungal agents may prevent severe pulmonary disease in groups considered to be at high risk, such as elderly individuals, persons with diabetes, and smokers. Persons at risk for severe CM may benefit from vaccination once an effective CM vaccine is available.

An outbreak of serogroup W-135 meningococcal disease occurred during the 2000 Hajj in Saudi Arabia. Disease was reported worldwide in Hajj pilgrims and their close contacts; however, most cases were identified in Saudi Arabia. Trends in Saudi meningococcal disease were evaluated and the epidemiology of Saudi cases from this outbreak described. Saudi national meningococcal disease incidence data for 1990 to 2000 were reviewed; cases from January 24 to June 5, 2000 were retrospectively reviewed. The 2000 Hajj outbreak consisted of distinct serogroup A and serogroup W-135 outbreaks. Of 253 identified cases in Saudi Arabia, 161 (64%) had serogroup identification; serogroups W-135 and A caused 93 (37%) and 60 (24%) cases with attack rates of 9 and 6 cases per 100,000 population, respectively. The 2000 Hajj outbreak was the first large serogroup W-135 meningococcal disease outbreak identified worldwide. Enhanced surveillance for serogroup W-135, especially in Africa, is essential to control this emerging epidemic disease.

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