Severe acute respiratory syndrome, Beijing, 2003

The largest outbreak of severe acute respiratory syndrome (SARS) struck Beijing in spring 2003. Multiple importations of SARS to Beijing initiated transmission in several healthcare facilities. Beijing's outbreak began March 5; by late April, daily hospital admissions for SARS exceeded 100 for several days; 2,521 cases of probable SARS occurred. Attack rates were highest in those 20-39 years of age; 1% of cases occurred in children <10 years. The case-fatality rate was highest among patients >65 years (27.7% vs. 4.8% for those 20-64 years, p < 0.001). Healthcare workers accounted for 16% of probable cases. The proportion of case-patients without known contact to a SARS patient increased significantly in May. Implementation of early detection, isolation, contact tracing, quarantine, triage of case-patients to designated SARS hospitals, and community mobilization ended the outbreak.     

SARS-associated coronavirus transmission, United States

To better assess the risk for transmission of the severe acute respiratory syndrome-associated coronavirus (SARS-CoV), we obtained serial specimens and clinical and exposure data from seven confirmed U.S. SARS patients and their 10 household contacts. SARS-CoV was detected in a day-14 sputum specimen from one case-patient and in five stool specimens from two case-patients. In one case-patient, SARS-CoV persisted in stool for at least 26 days after symptom onset. The highest amounts of virus were in the day-14 sputum sample and a day-14 stool sample. Residual respiratory symptoms were still present in recovered SARS case-patients 2 months after illness onset. Possible transmission of SARS-CoV occurred in one household contact, but this person had also traveled to a SARS-affected area. The data suggest that SARS-CoV is not always transmitted efficiently. Routine collection and testing of stool and sputum specimens of probable SARS case-patients may help the early detection of SARS-CoV infection.     

Risk factors for SARS among persons without known contact with SARS patients, Beijing, China

Most cases of severe acute respiratory syndrome (SARS) have occurred in close contacts of SARS patients. However, in Beijing, a large proportion of SARS cases occurred in persons without such contact. We conducted a case-control study in Beijing that compared exposures of 94 unlinked, probable SARS patients with those of 281 community-based controls matched for age group and sex. Case-patients were more likely than controls to have chronic medical conditions or to have visited fever clinics (clinics at which possible SARS patients were separated from other patients), eaten outside the home, or taken taxis frequently. The use of masks was strongly protective. Among 31 case-patients for whom convalescent-phase (>21 days) sera were available, 26% had immunoglobulin G to SARS-associated coronavirus. Our finding that clinical SARS was associated with visits to fever clinics supports Beijing's strategy of closing clinics with poor infection-control measures. Our finding that mask use lowered the risk for disease supports the community's use of this strategy.     

SARS transmission, risk factors, and prevention in Hong Kong

We analyzed information obtained from 1,192 patients with probable severe acute respiratory syndrome (SARS) reported in Hong Kong. Among them, 26.6% were hospital workers, 16.1% were members of the same household as SARS patients and had probable secondary infections, 14.3% were Amoy Gardens residents, 4.9% were inpatients, and 9.9% were contacts of SARS patients who were not family members. The remaining 347 case-patients (29.1%) had undefined sources of infection. Excluding those <16 years of age, 330 patients with cases from "undefined" sources were used in a 1:2 matched case-control study. Multivariate analysis of this case-control study showed that having visited mainland China, hospitals, or the Amoy Gardens were risk factors (odds ratio [OR] 1.95 to 7.63). In addition, frequent mask use in public venues, frequent hand washing, and disinfecting the living quarters were significant protective factors (OR 0.36 to 0.58). In Hong Kong, therefore, community-acquired infection did not make up most transmissions, and public health measures have contributed substantially to the control of the SARS epidemic.     

Use of quarantine to prevent transmission of severe acute respiratory syndrome--Taiwan, 2003

On July 5, 2003, Taiwan was removed from the World Health Organization (WHO) list of severe acute respiratory syndrome (SARS)-affected countries. As of July 9, a total of 671 probable cases of SARS had been reported in Taiwan. On February 21, the first identified SARS patient in Taiwan returned from travel to Guangdong Province, mainland China, by way of Hong Kong. Initial efforts to control SARS appeared to be effective; these efforts included isolation of suspect and probable SARS patients, use of personal protective equipment (PPE) for health-care workers (HCWs) and visitors, and quarantine of contacts of known SARS patients. However, beginning in mid-April, unrecognized cases of SARS led to a large nosocomial cluster and subsequent SARS-associated coronavirus transmission to other health-care facilities and community settings. In response to the growing epidemic, additional measures were taken to limit nosocomial and community transmission of SARS, including more widespread use of quarantine. By the end of the epidemic, 131,132 persons had been placed in quarantine, including 50,319 close contacts of SARS patients and 80,813 travelers from WHO-designated SARS-affected areas. This report describes the quarantine measures used in Taiwan and discusses the need for further evaluation of quarantine and other control measures used to prevent SARS.     

Superspreading SARS events, Beijing, 2003

Superspreading events were pivotal in the global spread of severe acute respiratory syndrome (SARS). We investigated superspreading in one transmission chain early in Beijing's epidemic. Superspreading was defined as transmission of SARS to at least eight contacts. An index patient with onset of SARS 2 months after hospital admission was the source of four generations of transmission to 76 case-patients, including 12 healthcare workers and several hospital visitors. Four (5%) case circumstances met the superspreading definition. Superspreading appeared to be associated with older age (mean 56 vs. 44 years), case fatality (75% vs. 16%, p = 0.02, Fisher exact test), number of close contacts (36 vs. 0.37) and attack rate among close contacts (43% vs. 18.5%, p < 0.025). Delayed recognition of SARS in a hospitalized patient permitted transmission to patients, visitors, and healthcare workers. Older age and number of contacts merit investigation in future studies of superspreading.     

一起小学校内乙型流感暴发的调查

2004年9月下旬，浙江省江山市某乡镇中心小学发生了一起由乙型流感病毒引起流行性感冒暴发。经调查本次乙型流感共发现患者65例，罹患率15．26％。     

一起传染性非典型肺炎爆发的“超级传播者”和传播链分析

目的：了解严重急性呼吸综合征(SARS)爆发案例的传播过程，分析SARS病例不同阶段的传染性和不同接触方式的危险性。方法：设计统一调查表，用查阅病历、面对面调查和电话调查相结合的方式进行，以指征病例为起点进行线索追踪和个案调查。用传播链示意图分析传播关系，用接触史分析示意图分析传染性。结果：共追查到与该案例传播链相关的接触者207人，发病36例，死亡1例，总罹患率为17％。其中指征病例和1名二代病例分别直接传播了12例和13例续发病例，其传播过程可以用清晰的传播链加以描述；所有36例病例均与前代病例的症状期有密切接触史，家族传播链中85％的病例都与前代病例症状期的第3—5天有过接触，发病前后均接触和仅发病后接触者罹患率分别为70％和67％，差异无显著性；仅与前代病例潜伏期接触的15名同柜台同事、29名同班同学无发病，38名与医护人员发病前或发病初期密切接触的家属无发病。结论：该案例所有的续发病例都有与症状期病例密切接触史；未观察到SARS患者在其潜伏期内存在传染性。     

Public health interventions and SARS spread, 2003

The 2003 outbreak of severe acute respiratory syndrome (SARS) was contained largely through traditional public health interventions, such as finding and isolating case-patients, quarantining close contacts, and enhanced infection control. The independent effectiveness of measures to "increase social distance" and wearing masks in public places requires further evaluation. Limited data exist on the effectiveness of providing health information to travelers. Entry screening of travelers through health declarations or thermal scanning at international borders had little documented effect on detecting SARS cases; exit screening appeared slightly more effective. The value of border screening in deterring travel by ill persons and in building public confidence remains unquantified. Interventions to control global epidemics should be based on expert advice from the World Health Organization and national authorities. In the case of SARS, interventions at a country's borders should not detract from efforts to identify and isolate infected persons within the country, monitor or quarantine their contacts, and strengthen infection control in healthcare settings.     

SARS surveillance during emergency public health response, United States, March-July 2003

In response to the emergence of severe acute respiratory syndrome (SARS), the United States established national surveillance using a sensitive case definition incorporating clinical, epidemiologic, and laboratory criteria. Of 1,460 unexplained respiratory illnesses reported by state and local health departments to the Centers for Disease Control and Prevention from March 17 to July 30, 2003, a total of 398 (27%) met clinical and epidemiologic SARS case criteria. Of these, 72 (18%) were probable cases with radiographic evidence of pneumonia. Eight (2%) were laboratory-confirmed SARS-coronavirus (SARS-CoV) infections, 206 (52%) were SARS-CoV negative, and 184 (46%) had undetermined SARS-CoV status because of missing convalescent-phase serum specimens. Thirty-one percent (124/398) of case-patients were hospitalized; none died. Travel was the most common epidemiologic link (329/398, 83%), and mainland China was the affected area most commonly visited. One case of possible household transmission was reported, and no laboratory-confirmed infections occurred among healthcare workers. Successes and limitations of this emergency surveillance can guide preparations for future outbreaks of SARS or respiratory diseases of unknown etiology.     

Epidemiologic clues to SARS origin in China

An epidemic of severe acute respiratory syndrome (SARS) began in Foshan municipality, Guangdong Province, China, in November 2002. We studied SARS case reports through April 30, 2003, including data from case investigations and a case series analysis of index cases. A total of 1,454 clinically confirmed cases (and 55 deaths) occurred; the epidemic peak was in the first week of February 2003. Healthcare workers accounted for 24% of cases. Clinical signs and symptoms differed between children (<18 years) and older persons (> or =65 years). Several observations support the hypothesis of a wild animal origin for SARS. Cases apparently occurred independently in at least five different municipalities; early case-patients were more likely than later patients to report living near a produce market (odds ratio undefined; lower 95% confidence interval 2.39) but not near a farm; and 9 (39%) of 23 early patients, including 6 who lived or worked in Foshan, were food handlers with probable animal contact.     

Contact Tracing Activities during the Ebola Virus Disease Epidemic in Kindia and Faranah,Guinea, 2014

The largest recorded Ebola virus disease epidemic began in March 2014; as of July 2015, it continued in 3 principally affected countries: Guinea, Liberia, and Sierra Leone. Control efforts include contact tracing to expedite identification of the virus in suspect case-patients. We examined contact tracing activities during September 20–December 31, 2014, in 2 prefectures of Guinea using national and local data about case-patients and their contacts. Results show less than one third of case-patients (28.3% and 31.1%) were registered as contacts before case identification; approximately two thirds (61.1% and 67.7%) had no registered contacts. Time to isolation of suspected case-patients was not immediate (median 5 and 3 days for Kindia and Faranah, respectively), and secondary attack rates varied by relationships of persons who had contact with the source case-patient and the type of case-patient to which a contact was exposed. More complete contact tracing efforts are needed to augment control of this epidemic.     

Severe acute respiratory syndrome (SARS) in Singapore: clinical features of index patient and initial contacts

Severe acute respiratory syndrome (SARS) is an emerging viral infectious disease. One of the largest outbreaks of SARS to date began in Singapore in March 2003. We describe the clinical, laboratory, and radiologic features of the index patient and the patient's initial contacts affected with probable SARS.     

Ebola hemorrhagic fever transmission and risk factors of contacts, Uganda

From August 2000 through January 2001, a large epidemic of Ebola hemorrhagic fever occurred in Uganda, with 425 cases and 224 deaths. Starting from three laboratory-confirmed cases, we traced the chains of transmission for three generations, until we reached the primary case-patients (i.e., persons with an unidentified source of infection). We then prospectively identified the other contacts in whom the disease had developed. To identify the risk factors associated with transmission, we interviewed both healthy and ill contacts (or their proxies)who had been reported by the case-patients (or their proxies) and who met the criteria set for contact tracing during surveillance. The patterns of exposure of 24 case-patients and 65 healthy contacts were defined, and crude and adjusted prevalence proportion ratios (PPR) were estimated for different types of exposure. Contact with the patient's body fluids (PPR = 4.61%, 95% confidence interval 1.73 to 12.29) was the strongest risk factor, although transmission through fomites also seems possible.     

Outbreak of serogroup W135 meningococcal disease after the Hajj pilgrimage,Europe, 2000

The 2000 Hajj (March 15-18) was followed by an outbreak of Neisseria meningitidis W135 2a: P1.2,5 in Europe. From March 18 to July 31, 2000, some 90 cases of meningococcal infection were reported from nine countries, mostly the United Kingdom (UK) and France; 14 cases were fatal. Although most early cases were in pilgrims, the outbreak spread to their contacts and then to those with no known pilgrim contact. In France and the UK, the outbreak case-fatality rate was compared with the rate reported from national surveillance. The risk of dying during this outbreak was higher in France and the UK, although the difference was not statistically significant. Prophylaxis for all pilgrims and their household contacts was offered in France; in the UK and other European countries, prophylaxis was recommended only for close contacts. No difference in transmission rates following intervention was detected between France and the UK.     

Use of antiviral drugs to reduce household transmission of pandemic (H1N1) 2009, United Kingdom

The United Kingdom implemented a containment strategy for pandemic (H1N1) 2009 through administering antiviral agents (AVs) to patients and their close contacts. This observational household cohort study describes the effect of AVs on household transmission. We followed 285 confirmed primary cases in 259 households with 761 contacts. At 2 weeks, the confirmed secondary attack rate (SAR) was 8.1% (62/761) and significantly higher in persons <16 years of age than in those >50 years of age (18.9% vs. 1.2%, p<0.001). Early (<48 hours) treatment of primary case-patients reduced SAR (4.5% vs. 10.6%, p = 0.003). The SAR in child contacts was 33.3% (10/30) when the primary contact was a woman and 2.9% (1/34) when the primary contact was a man (p = 0.010). Of 53 confirmed secondary case-patients, 45 had not received AV prophylaxis. The effectiveness of AV prophylaxis in preventing infection was 92%.     

Public health implications of cysticercosis acquired in the United States

Cysticercosis has emerged as a cause of severe neurologic disease in the United States that primarily affects immigrants from Latin America. Moreover, the relevance of cysticercosis as a public health problem has been highlighted by local transmission. We searched the biomedical literature for reports documenting cases of cysticercosis acquired in the United States. A total of 78 cases, principally neurocysticercosis, were reported from 12 states during 1954-2005. A confirmed or presumptive source of infection was identified among household members or close personal contacts of 16 (21%) case-patients. Several factors, including the severe, potentially fatal, nature of cysticercosis; its fecal-oral route of transmission; the considerable economic effect; the availability of a sensitive and specific serologic test for infection by adult Taenia solium tapeworms; and the demonstrated ability to find a probable source of infection among contacts, all provide a compelling rationale for implementation of public health control efforts.     

Severe acute respiratory syndrome surveillance in Australia.

In March 2003, the World Health Organization (WHO) issued a global alert recommending active worldwide surveillance for severe acute respiratory syndrome (SARS). This paper describes the epidemiological features of cases reported by Australian states and territories to the Australian Government Department of Health and Ageing between 17 March and 31 July 2003. There were 138 people investigated for SARS: 111 as suspect and 27 as probable. Five probable cases were reported to WHO after review of other possible diagnoses and Australia-specific exclusion criteria had been applied. An additional probable case identified by laboratory testing overseas, but who was not under investigation when in Australia, was also reported to WHO. The method by which surveillance for SARS was rapidly established provided an opportunity to examine Australia's planning and preparedness for future respiratory disease epidemics such as influenza.     

Fungal Endophthalmitis Associated with Compounded Products

Fungal endophthalmitis is a rare but serious infection. In March 2012, several cases of probable and laboratory-confirmed fungal endophthalmitis occurring after invasive ocular procedures were reported nationwide. We identified 47 cases in 9 states: 21 patients had been exposed to the intraocular dye Brilliant Blue G (BBG) during retinal surgery, and the other 26 had received an intravitreal injection containing triamcinolone acetonide. Both drugs were produced by Franck’s Compounding Lab (Ocala, FL, USA). Fusarium incarnatum-equiseti species complex mold was identified in specimens from BBG-exposed case-patients and an unopened BBG vial. Bipolaris hawaiiensis mold was identified in specimens from triamcinolone-exposed case-patients. Exposure to either product was the only factor associated with case status. Of 40 case-patients for whom data were available, 39 (98%) lost vision. These concurrent outbreaks, associated with 1 compounding pharmacy, resulted in a product recall. Ensuring safety and integrity of compounded medications is critical for preventing further outbreaks associated with compounded products.