Respiratory infections during SARS outbreak, Hong Kong, 2003.The effect of community hygienic hy·gien·ic adj. 1. Of or relating to hygiene. 2. Tending to promote or preserve health. 3. Sanitary. measures during the outbreak of severe acute respiratory syndrome Severe Acute Respiratory Syndrome (SARS) Definition Severe acute respiratory syndrome (SARS) is the first emergent and highly transmissible viral disease to appear during the twenty-first century. in Hong Kong Hong Kong (hŏng kŏng), Mandarin Xianggang, special administrative region of China, formerly a British crown colony (2005 est. pop. 6,899,000), land area 422 sq mi (1,092 sq km), adjacent to Guangdong prov. was studied by comparing the proportion of positive specimens of various respiratory viruses in 2003 with those from 1998 to 2002. Community hygienic measures significantly reduced the incidence of various respiratory viral infections. ********** Severe acute respiratory syndrome (SARS) is an infection caused by a novel coronavirus coronavirus /co·ro·na·vi·rus/ (ko-ro´nah-vi?rus) any virus belonging to the family Coronaviridae. Coronavirus /Co·ro·na·vi·rus/ (ko-ro´nah-vi?rus that is transmitted primarily through direct mucous membrane mucous membrane n. A membrane lining all body passages that communicate with the exterior, such as the respiratory, genitourinary, and alimentary tracts, and having cells and associated glands that secrete mucus. Also called mucosa. contact with infectious respiratory droplets and through exposure to fomites fomites see fomes. . In 2003, Hong Kong reported SARS cases from March 11 to June 2. During the height of the outbreak, schools were suspended, social activities were curtailed with the closure of various public places, and the community was engaged in a sustained and intense hygiene campaign (1-3). Population education on personal hygienic measures was spearheaded by the government with concerted efforts from various organizations and the community. Surveys conducted in April and May 2003 showed that most of the population wore a face mask Face mask The simplest way of delivering a high level of oxygen to patients with ARDS or other low-oxygen conditions. Mentioned in: Adult Respiratory Distress Syndrome (76%), washed their hands after contact with potentially contaminated contaminated, v 1. made radioactive by the addition of small quantities of radioactive material. 2. made contaminated by adding infective or radiographic materials. 3. an infective surface or object. objects (65%), used soap when washing hands (75%), covered their mouths when sneezing To verbally tell somebody about a new and interesting Web site. See viral marketing. or coughing (78%), and used diluted bleach for household cleaning (>50%) (4,5). Another survey on health-seeking behavioral traits conducted in June 2003 showed that >70% of respondents practiced some of these hygienic measures more frequently during the SARS outbreak than during the pre-SARS period (6). The Study We postulated that these populationwide anti-SARS measures would have effects on other infections spread by the respiratory route. In this study, we examined whether such measures also affected the incidence of some common acute viral respiratory infections. The study period was January 1, 1998, to December 31, 2003. Data were obtained from the Government Virus Unit (GVU GVU Graphics, Visualization and Usability (Georgia Tech) GVU Greenville Update (newsletter) GVU Generic Virtual User (Sprint) ), a public health and diagnostic virology virology, study of viruses and their role in disease. Many viruses, such as animal RNA viruses and viruses that infect bacteria, or bacteriophages, have become useful laboratory tools in genetic studies and in work on the cellular metabolic control of gene expression laboratory serving public and private hospitals and outpatient clinics in Hong Kong. At GVU, all respiratory specimens are routinely cultured using 4 continuous cell lines, Rhesus monkey rhesus monkey: see macaque. rhesus monkey Sand-coloured macaque (Macaca mulatta), widespread in South and Southeast Asian forests. Rhesus monkeys are 17–25 in. (43–64 cm) long, excluding the furry 8–12-in. kidney, Madin-Darby canine kidney, rhabdomyosarcoma rhabdomyosarcoma /rhab·do·myo·sar·co·ma/ (mi?o-sahr-ko´mah) a highly malignant tumor of striated muscle derived from primitive mesenchymal cells. , and human laryngeal laryngeal /lar·yn·ge·al/ (lah-rin´je-al) pertaining to the larynx. la·ryn·geal or la·ryn·gal adj. Of, relating to, affecting, or near the larynx. epithelium, which could support the growth of various viruses including influenza, parainfluenza parainfluenza Infectious disease A virus that causes URIs–up to 50% of croup and 10–15% of bronchiolitis, bronchitis, pneumonias in toddlers Clinical Rhinorrhea, cold-like Sx Risk factors Preschool children; by school age most children have been exposed , respiratory syncytial virus respiratory syncytial virus (sĭnsĭsh`əl): see cold, common. (RSV RSV respiratory syncytial virus; Rous sarcoma virus. RSV abbr. respiratory syncytial virus RSV 1 Respiratory syncytial virus, see there 2 Rous sarcoma virus, see there ), and adenovirus adenovirus Any of a group of spheroidal viruses, made up of DNA wrapped in a protein coat, that cause sore throat and fever in humans, hepatitis in dogs, and several diseases in fowl, mice, cattle, pigs, and monkeys. . On detection of specific cytopathic effects, the viruses are identified with standard protocols (7). For each month of the study period, we obtained the number of respiratory virus isolates as a proportion of the total number of respiratory specimens processed by GVU. We computed the percentage change in the proportion of positive specimens (PPS (Packets Per Second) The measurement of activity in a local area network (LAN). In LANs such as Ethernet, Token Ring and FDDI, as well as the Internet, data is broken up and transmitted in packets (frames), each with a source and destination address. ) for each virus between each month of 2003 and the mean PPS in the same month of the preceding 5 years (1998-2002), which served as the reference period. For comparison purposes, we obtained the monthly number of positive tests for immunoglobulin M immunoglobulin M n. Abbr. IgM The class of antibodies found in circulating body fluids and the first antibodies to appear in response to an initial exposure to an antigen. (IgM) antibody against hepatitis B core antigen hepatitis B core antigen n. Abbr. HBcAg A core protein antigen of the hepatitis B virus found on the Dane particle and also in hepatocyte nuclei in hepatitis B infections. (anti-HBc) and the corresponding total number of tests performed in the study period. The percentage change in PPS was calculated as above. Although a positive IgM anti-HBc test result indicates acute hepatitis acute hepatitis Clinical medicine Liver inflammation of abrupt onset, which may be due to a viral infection–eg HAV or toxins Clinical Low-grade fever, anorexia, N&V, fatigue, malaise, headache, photophobia, pharyngitis, cough; later, dark urine, light B infection or an exacerbation of chronic hepatitis Chronic hepatitis Long lasting inflammation of the liver due to viruses or other causes. Mentioned in: Tube Compression of the Esophagus and Stomach chronic hepatitis B infection, as we were testing the same catchment of population throughout 1998 to 2003, the proportion of exacerbations of chronic hepatitis B infection is assumed to have remained unchanged during the study period. The Table shows the change in PPS in 2003 for the various viruses in comparison with the reference period. In 2003, the monthly number of respiratory specimens ranged from 665 to 5,432 (mean 1,399), in comparison with a range throughout the years 1998-2002 of 757 to 3,162 (mean 1,334.5). A surge in the number of specimens was noted during March and April 2003 (5,432 and 3,758, respectively). During March to July 2003, marked reductions in PPS occurred compared with the reference period for influenza virus influenza virus n. Any of three viruses of the genus Influenzavirus designated type A, type B, and type C, that cause influenza and influenzalike infections. , parainfluenza virus parainfluenza virus n. Any of five types of viruses of the genus Paramyxovirus that are associated with various respiratory infections, especially in children. , RSV, and adenovirus, particularly in the months of April, May, and June. This reduction corresponded to the period when anti-SARS measures in the community were most rigorous. In contrast, similar changes in PPS were not observed for hepatitis B Hepatitis B Definition Hepatitis B is a potentially serious form of liver inflammation due to infection by the hepatitis B virus (HBV). It occurs in both rapidly developing (acute) and long-lasting (chronic) forms, and is one of the most common chronic , which is caused by a bloodborne virus with a different mode of transmission than that of the 4 respiratory viruses (Figure 1). Since August 2003, instead of reductions in PPS, a rebound in isolation rates was observed for the 4 viruses. The 2003 SARS outbreak overlapped with the traditional seasonal peak from March to September for RSV in Hong Kong (8). In 2003, the RSV peak season shifted to August-October. The accumulation of susceptible infants offset the infection control measures instituted against respiratory infections as well as the normal seasonality; as a result, RSV activity increased in the late months of 2003. Figure 2 illustrates the usual seasonal variation of the 4 respiratory viruses and their pattern from 1998 to 2003. Discerning whether the observed effects in our study were real or apparent is important. The surge in specimens during March and April 2003 suggested that physicians were more inclined to order tests for patients with respiratory symptoms at the height of the SARS outbreak. This fact could conceivably dilute PPS for respiratory viruses. However, since May 2003, the number of tests has returned to normal levels; however, PPS remained significantly decreased during May to July 2003. Thus, PPS reductions cannot be explained by a dilution effect caused by an increased number of specimens processed. Furthermore, after we controlled for the patients' age group differences, PPS for influenza virus remained depressed when compared to PPS in the reference period (data not shown). The same pattern was true for adenovirus. Population coverage for influenza vaccination in Hong Kong has been <15% throughout the study period (A. Chan, pers. comm.), so vaccination was unlikely to have resulted in reduced influenza circulation in the community. The concomitant significant reduction in PPS for all 4 respiratory viruses in the same period argues against 2003's being a milder year for influenza. Temporally, the moderation of PPS reductions since August 2003 (the last SARS case was reported on June 2) supported the hypothesis that the effects of populationwide anti-SARS measures on the incidence of respiratory viruses were real. With the recent outbreaks of highly pathogenic avian influenza avian influenza: see influenza. among poultry in Asian countries, and the associated human infections, pandemic pandemic /pan·dem·ic/ (pan-dem´ik) 1. a widespread epidemic of a disease. 2. widely epidemic. pan·dem·ic adj. Epidemic over a wide geographic area. n. planning for influenza has been undertaken with renewed efforts on a worldwide basis (9). In pandemic preparedness planning, control measures have traditionally focused on the use of antiviral antiviral /an·ti·vi·ral/ (-vi´ral) destroying viruses or suppressing their replication, or an agent that so acts. an·ti·vi·ral adj. chemotherapy and the expedient development of an effective vaccine. However, such strategies may not be feasible, especially in countries with limited resources. An effective vaccine would probably become available only during the latter phase of the pandemic. Information concerning the effects of increased social distance and communitywide hygiene measures on the incidence of common viral respiratory infections at a population level has been lacking. The SARS outbreak offers a unique opportunity to study the association. Although our study was observational and thus could not establish a causal relationship, it suggests a possible association between population-based hygienic measures and the reduced incidence of influenza and other acute viral respiratory infections. However, the relative contribution of each of these measures could not be estimated in our study. The effective implementation of such measures requires determined and sustained educational efforts from health authorities with collaboration of the public. We thus propose that stockpiling personal protective equipment and having public education campaigns on infection control practices should form an integral component in pandemic planning for the emergence of novel influenza virus strains in humans. Acknowledgments We thank the staff of the Government Virus Unit for their technical assistance. References (1.) SARS Expert Committee. SARS in Hong Kong: from experience to action. Report of the SARS Expert Committee. [cited 2005 Aug 20]. Available from http://www.sars-expertcom.gov.hk/english/reports/ reports.html. (2.) Leisure and Cultural Services Department The Leisure and Cultural Services Department (Traditional Chinese: 康樂及文化事務署 . Additional precautionary measures at LCSD LCSD Leisure and Cultural Services Department (Hong Kong) LCSD Logan City School District LCSD Left Cardiac Sympathetic Denervation LCSD Lee County School District (Lee County, Florida) facilities and functions. Press release 27 March 2003. [cited 2005 Aug 20]. Available from http://www.info.gov. hk/gia/generat/200303/27/0327250.htm (3.) Housing Authority. HA shopping centre activities postponed. Press release 28 March 2003. [cited 2005 Aug 20]. Available from http://www.info.gov.hk/gia/general/200303/28/0328183.htm (4.) Leung GM, Lam TH, Ho LM, Ho SY, Chan BH, Wong IO, et al. The impact of community psychological responses on outbreak control for severe acute respiratory syndrome in Hong Kong. J Epidemiol Community Health. 2003;57:857-63. (5.) Cheng C. Report on the public responses to the SARS outbreak in Hong Kong [Monograph]. [cited 2005 Aug 20]. Available from http://www.ust.hk/src/Researche.html (6.) Lau JT, Yang X, Tsui HY, Kim JH. Impacts of SARS on health-seeking behaviors in general population in Hong Kong. Prev Med. 2005;41:454-62. (7.) Lennette EH, Lennette DA, Lennette ET, editors. Diagnostic procedures for viral, rickettsial rickettsial /rick·ett·si·al/ (ri-ket´se-al) pertaining to or caused by rickettsiae. rick·ett·si·al adj. Relating to, or caused by a member of the genus Rickettsia. , and chlamydial chlamydial pertaining to members of the family Chlamydiaceae. chlamydial abortion abortion in cows, ewes, sows and goat does caused by Chlamydophila abortus and C. pecorum. See enzootic abortion of ewes. infections. 7th ed. Washington: American Public Health Association The American Public Health Association (APHA) is Washington, D.C.-based professional organization for public health professionals in the United States. Founded in 1872 by Dr. Stephen Smith, APHA has more than 30,000 members worldwide. ; 1995. (8.) Lo JYC JYC Joyce Corporation Limited (stock symbol) JYC Jacques Yves Cousteau (oceanographer) JYC Jackson Yacht Club (Mississippi) JYC Jamestown Yacht Club , Lim WWL WWL World Wide Lexicon WWL Working Load Limit WWL world wide localization WWL world wide language , Yeung AFY AFY Acre-Feet Per Year (engineering) AFY All for You (band) AFY As For You . Respiratory syncytial virus infection Respiratory Syncytial Virus Infection Definition Respiratory syncytial virus (RSV) is a virus that can cause severe lower respiratory infections in children under the age of two, and milder upper respiratory infections in older children and adults. in Hong Kong, 1990 91. Journal of the Hong Kong Medical Association. 1994;46:42-5. (9.) Ungchusak K, Auewarakul P, Dowell SF, Kitphati R, Auwanit W, Puthavathana P, et al. Probable person-to-person transmission of avian influenza A (H5N1). N Engl J Med. 2005;352:333-40. Address for correspondence: Wilina W.L. Lim, Virology Division, Public Health Laboratory Centre, 382 Nam Cheong St, Shek Kip Mei Shek Kip Mei (Chinese: 石硤尾), originally known as Kap Shek Mi, is an area in New Kowloon, the North Eastern Kowloon Peninsula of Hong Kong. History , Kowloon, Hong Kong SAR (Segmentation And Reassembly) The protocol that converts data to cells for transmission over an ATM network. It is the lower part of the ATM Adaption Layer (AAL), which is responsible for the entire operation. See AAL. SAR - segmentation and reassembly , People's Republic People's Republic n. A political organization founded and controlled by a national Communist party. of China; fax: 852-2319-5989; email: wllim@pacific.net.hk Janice Y.C. Lo, * Thomas H.F. Tsang, * Yiu-Hong Leung, * Eugene Y.H. Yeung, * Thomson Wu, * and Wilina W. L. Lim * * Department of Health, Hong Kong Special Administrative Region A special administrative region may be:
Dr Lo is acting consultant medical microbiologist at the Microbiology Division of the Public Health Laboratory Services Branch, Centre for Health Protection, Department of Health, Government of the Hong Kong Special Administrative Region, People's Republic of China. Her research interests include the application of virologic and microbiologic diagnostic techniques in the epidemiologic study epidemiologic study A study that compares 2 groups of people who are alike except for one factor, such as exposure to a chemical or the presence of a health effect; the investigators try to determine if any factor is associated with the health effect of infectious diseases of public health significance.
Table. Change in proportion of positive specimens (PPS) in 2003 for
various viruses with reference to the period 1998-2002 *
Virus Jan Feb Mar
Influenza
No. isolates 327 419 786
No. tests performed 1,166 1,530 5,432
PPS (03) 0.28 0.27 0.14
Average PPS (98-02) 0.235 0.368 0.329
Range of PPS (98-02) 0.067- 0.143- 0.121-
0.321 0.519 0.517
% change ([dagger]) +19 -26 -56
Parainfluenza
No. isolates 29 35 75
No. tests performed 1,166 1,530 5,432
PPS (03) 0.02 0.02 0.01
Average PPS (98-02) 0.035 0.025 0.022
Range of PPS (98-02) 0.014- 0.014- 0.008-
0.106 0.053 0.046
% change ([dagger]) -28 -8 -38
RSV
No. isolates 49 53 66
No. tests performed 1,166 1,530 5,432
PPS (03) 0.04 0.03 0.01
Average PPS (98-02) 0.014 0.021 0.055
Range of PPS (98-02) 0.003- 0.010- 0.037-
0.054 0.065 0.090
% change ([dagger]) +203 +64 -78
Adenovirus
No. isolates 61 78 84
No. tests performed 1,166 1,530 5,432
PPS (03) 0.05 0.05 0.02
Average PPS (98-02) 0.034 0.030 0.035
Range of PPS (98-02) 0.012- 0.019- 0.017-
+0.1 +0.1 0.071
% change ([dagger]) +52 +72 -55
Hepatitis B
No. of positive test 16 11 13
results
No. of tests performed 143 98 135
PPS (03) 0.112 0.112 0.096
Average PPS (98-02) 0.147 0.132 0.127
Range of PPS (98-02) 0.083- 0.079- 0.093-
0.228 0.190 0.153
% chante ([dagger]) -24 -15 -24
Virus Apr May Jun
Influenza
No. isolates 105 22 58
No. tests performed 3,758 1,495 974
PPS (03) 0.03 0.01 0.06
Average PPS (98-02) 0.154 0.127 0.143
Range of PPS (98-02) 0.065- 0.043- 0.072-
0.203 0.194 0.216
% change ([dagger]) -82 -88 -58
Parainfluenza
No. isolates 12 2 1
No. tests performed 3,758 1,495 974
PPS (03) 0.00 0.00 0.00
Average PPS (98-02) 0.036 0.037 0.034
Range of PPS (98-02) 0.021- 0.024- 0.026-
0.046 0.054 0.046
% change ([dagger]) -91 -96 -97
RSV
No. isolates 24 6 3
No. tests performed 3,758 1,495 974
PPS (03) 0.01 0.00 0.00
Average PPS (98-02) 0.104 0.081 0.066
Range of PPS (98-02) 0.055- 0.049- 0.042-
0.155 0.112 0.098
% change ([dagger]) -94 -95 -95
Adenovirus
No. isolates 41 5 0
No. tests performed 3758 1,495 974
PPS (03) 0.01 0.00 0.00
Average PPS (98-02) 0.056 0.055 0.058
Range of PPS (98-02) 0.012- 0.022- 0.028-
0.121 0.110 0.105
% change ([dagger]) -81 -94 -100
Hepatitis B
No. of positive test 18 20 13
results
No. of tests performed 99 97 118
PPS (03) 0.182 0.206 0.110
Average PPS (98-02) 0.129 0.125 0.156
Range of PPS (98-02) 0.070- 0.085- 0.096-
0.168 0.162 0.188
% chante ([dagger]) +41 +65 -29
Virus Jul Aug Sep
Influenza
No. isolates 96 54 121
No. tests performed 776 665 1,283
PPS (03) 0.12 0.08 0.09
Average PPS (98-02) 0.186 0.153 0.063
Range of PPS (98-02) 0.145- 0.123- 0.040-
0.232 0.173 0.105
% change ([dagger]) -33 -47 +49
Parainfluenza
No. isolates 11 26 29
No. tests performed 776 665 1,283
PPS (03) 0.01 0.04 0.02
Average PPS (98-02) 0.023 0.017 0.027
Range of PPS (98-02) 0.017- 0.010- 0.014-
0.034 0.028 0.043
% change ([dagger]) -38 +135 -16
RSV
No. isolates 8 53 181
No. tests performed 776 665 1,283
PPS (03) 0.01 0.08 0.14
Average PPS (98-02) 0.072 0.094 0.092
Range of PPS (98-02) 0.038- 0.046- 0.057-
0.113 0.126 0.118
% change ([dagger]) -86 -15 +54
Adenovirus
No. isolates 1 2 4
No. tests performed 776 665 1,283
PPS (03) 0.00 0.00 0.00
Average PPS (98-02) 0.068 0.044 0.038
Range of PPS (98-02) 0.032- 0.029- 0.026-
0.091 0.058 0.054
% change ([dagger]) -98 -93 -92
Hepatitis B
No. of positive test 19 20 22
results
No. of tests performed 139 135 120
PPS (03) 0.137 0.148 0.183
Average PPS (98-02) 0.154 0.156 0.168
Range of PPS (98-02) 0.104- 0.068- 0.086-
0.186 0.228 0.250
% chante ([dagger]) -11 -5 +9
Virus Oct Nov Dec
Influenza
No. isolates 50 10 35
No. tests performed 1,193 1,008 1,407
PPS (03) 0.04 0.01 0.02
Average PPS (98-02) 0.022 0.019 0.044
Range of PPS (98-02) 0.009- 0.008- 0.022-
0.044 0.030 0.110
% change ([dagger]) +87 -49 -44
Parainfluenza
No. isolates 68 75 112
No. tests performed 1,193 1,008 1,407
PPS (03) 0.06 0.07 0.08
Average PPS (98-02) 0.061 0.081 0.065
Range of PPS (98-02) 0.025- 0.031- 0.035-
0.102 0.149 0.156
% change ([dagger]) -7 -9 +22
RSV
No. isolates 48 12 5
No. tests performed 1,193 1,008 1,407
PPS (03) 0.04 0.01 0.00
Average PPS (98-02) 0.036 0.022 0.032
Range of PPS (98-02) 0.018- 0.001- 0.001-
0.051 0.060 0.072
% change ([dagger]) +13 -47 -89
Adenovirus
No. isolates 7 8 17
No. tests performed 1,193 1,008 1,407
PPS (03) 0.01 0.01 0.01
Average PPS (98-02) 0.049 0.052 0.074
Range of PPS (98-02) 0.045- 0.042- 0.058-
0.055 0.062 0.093
% change ([dagger]) -88 -85 -84
Hepatitis B
No. of positive test 21 15 20
results
No. of tests performed 111 102 131
PPS (03) 0.189 0.147 0.153
Average PPS (98-02) 0.144 0.167 0.148
Range of PPS (98-02) 0.081- 0.099- 0.082-
0.233 0.249 0.197
% chante ([dagger]) +32 -12 +3
* RSV, respiratory syncytial virus.
([dagger]) Percentage change of PPS in 2003 with respect to the
average PPS from 1998 to 2002.
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