Swine influenza a outbreak, Fort Dix, New Jersey, 1976.
In early 1976, the novel A/New Jersey/76 (Hsw1N1) influenza virus influenza virus
Any of three viruses of the genus Influenzavirus designated type A, type B, and type C, that cause influenza and influenzalike infections. caused severe respiratory illness Noun 1. respiratory illness - a disease affecting the respiratory system
respiratory disease, respiratory disorder
adult respiratory distress syndrome, ARDS, wet lung, white lung - acute lung injury characterized by coughing and rales; inflammation of the in 13 soldiers with 1 death at Fort Dix Fort Dix, U.S. army training center, 32,000 acres (12,950 hectares), central N.J., SE of Trenton; est. 1917 as Camp Dix and named for U.S. statesman John A. Dix. In 1939 it was made a permanent garrison and renamed Fort Dix. , New Jersey. Since A/New Jersey was similar to the 1918-1919 pandemic pandemic /pan·dem·ic/ (pan-dem´ik)
1. a widespread epidemic of a disease.
2. widely epidemic.
Epidemic over a wide geographic area.
n. virus, rapid outbreak assessment and enhanced surveillance were initiated. A/New Jersey virus was detected only from January 19 to February 9 and did not spread beyond Fort Dix. A/Victoria/75 (H3N2) spread simultaneously, also caused illness, and persisted until March. Up to 230 soldiers were infected with the A/New Jersey virus. Rapid recognition of A/New Jersey, swift outbreak assessment, and enhanced surveillance resulted from excellent collaboration between Fort Dix, New Jersey Department of Health, Walter Reed Army Institute of Research This article is about the U.S. Army medical research institute (not the hospital). Otherwise, see Walter Reed (disambiguation).
The Walter Reed Army Institute of Research (WRAIR) is the largest biomedical research facility administered by the U.S. , and Center for Disease Control personnel. Despite efforts to define the events at Fort Dix, many questions remain unanswered, including the following: Where did A/New Jersey come from? Why did transmission stop?
Revisiting events surrounding the 1976 swine influenza swine influenza
A highly contagious form of human influenza caused by a filterable virus identical or related to a virus formerly isolated from infected swine. Also called swine flu. A (H 1N 1) outbreak may assist those planning for the rapid identification and characterization of threatening contemporary viruses, like avian influenza avian influenza: see influenza. A (H5N1) (1). The severity of the 1918 influenza A influenza A
Influenza caused by infection with a strain of influenza virus type A.
influenza A Infectious disease An avian virus, especially of ducks–which in China live near the pig reservoir and 'vector'; (H1N1) pandemic and evidence for a cycle of pandemics aroused concern that the 1918 disaster could recur (2,3). Following the 1918 pandemic, H1N1 strains circulated until the "Asian" influenza A (H2N2) pandemic in 1957 (3). When in early 1976, cases of influenza influenza or flu, acute, highly contagious disease caused by a virus; formerly known as the grippe. There are three types of the virus, designated A, B, and C, but only types A and B cause more serious contagious infections. in soldiers, mostly recruits, at Fort Dix, New Jersey, were associated with isolation of influenza A (H1N1) serotypes (which in 1976 were labeled Hsw1N1), an intense investigation followed (4).
Of 19,000 people at Fort Dix in January 1976, [approximately equal to] 32% were recruits (basic trainees) (4). Recruits reported to Fort Dix for 7 weeks of initial training through the basic training reception center, where they lived and were processed into the Army during an intense 3 days of examinations, administrative procedures, and indoctrination in·doc·tri·nate
tr.v. in·doc·tri·nat·ed, in·doc·tri·nat·ing, in·doc·tri·nates
1. To instruct in a body of doctrine or principles.
2. . At the reception center, training unit cohorts were formed. Recruits were grouped into 50-member units (platoons) and organized into companies of 4 platoons each. Units formed by week's end moved from the reception center to the basic training quarters. To prevent respiratory illnesses, recruits were isolated in their company areas for 2 weeks and restricted to the military post for 4 weeks (4). Platoon platoon
Principal subdivision of a military company, battery, or troop. Usually commanded by a lieutenant, it consists of 25–50 soldiers organized into two or more squads led by noncommissioned officers. members had close contact with other platoon members, less contact with other platoons in their company, and even less contact with other companies.
On arrival, recruits received the 1975 1976 influenza vaccine influenza vaccine Flu vaccine A vaccine recommended for those at high risk for serious complications from influenza: > age 65; Pts with chronic diseases of heart, lung or kidneys, DM, immunosuppression, severe anemia, nursing home and other chronic-care (A/Port Chalmers/1/73 [H3N2], A/Scotland/840/ 74 [H3N2], and B/Hong Kong/15/72) (4). Other soldiers reported directly to advanced training programs of 4 to 12 weeks at Fort Dix immediately after basic training at Fort Dix or elsewhere. These soldiers received influenza vaccinations in basic training. Civilian employees and soldiers' families were offered vaccine, but only an estimated <40% accepted (4).
Training stopped over the Christmas-New Year's holidays and resumed on January 5, 1976, with an influx of new trainees. The weather was cold (wind chill factors wind chill factor Wilderness medicine An index used to adjust the actual air temperature to express the intensity of cooling expected from a cold environment as a function of the ambient temperature and wind speed; the WCF is a measure of the effect of air of 0[degrees] to -43[degrees]F), and the reception center was crowded (4). Resumption of training was associated with an explosive febrile febrile /feb·rile/ (feb´ril) pertaining to or characterized by fever.
Of, relating to, or characterized by fever; feverish. respiratory disease Noun 1. respiratory disease - a disease affecting the respiratory system
respiratory disorder, respiratory illness
adult respiratory distress syndrome, ARDS, wet lung, white lung - acute lung injury characterized by coughing and rales; inflammation of the outbreak involving new arrivals and others. Throat swabs were collected from a sample of hospitalized soldiers with this syndrome. On January 23, the Fort Dix preventive medicine preventive medicine, branch of medicine dealing with the prevention of disease and the maintenance of good health practices. Until recently preventive medicine was largely the domain of the U.S. physician learned of 2 isolations of 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. type 21 and suspected an adenovirus outbreak (4). He notified the county health department and the New Jersey (NJ) Department of Health of the outbreak (4). On January 28, an NJ Department of Health official consulted with the military physician and suggested that the explosive, widespread outbreak could be influenza (4). Over the next 2 days, 19 specimens were delivered to the state laboratory and 7 A/Victoria-like viruses and 3 unknown hemagglutinating agents were identified (4). Specimens were flown to the Center for Disease Control (CDC See Control Data, century date change and Back Orifice.
CDC - Control Data Corporation ), Atlanta, Georgia, on February 6, where a fourth unknown agent was found (4).
On February 2, Fort Dix and NJ Department of Health personnel arranged for virologic studies of deaths possibly caused by influenza (4). Tracheal tracheal
pertaining to or emanating from trachea.
see transtracheal aspiration.
tracheal band sign
on contrast radiography of a dilated esophagus, the impression made ventrally by the trachea. swabs taken on February 5 from a recruit who died on February 4 yielded a fifth unknown agent on February 9. By February 10, laboratory evidence had confirmed that a novel influenza strain was circulating at Fort Dix and that 2 different influenza strains were causing disease. By February 13, all 5 unknown strains were identified as swine influenza A (Hsw1N1). The possibility of laboratory contamination was evaluated (4). No known swine influenza A strains were present in the NJ Department of Health Virus Laboratory before the Fort Dix outbreak. Additionally, all unknown Fort Dix viruses were independently isolated from original specimens at CDC and the Walter Reed Army Institute of Research (WRAIR WRAIR Walter Reed Army Institute of Research ), Washington, DC. Also, 2 patients with novel virus isolates had convalescent-phase, homologous homologous /ho·mol·o·gous/ (ho-mol´ah-gus)
1. corresponding in structure, position, origin, etc.
1. , hemagglutination-inhibition (HAI HAI Health Action International
HAI Healthcare-Associated Infections
HAI Helicopter Association International
HAI Hospital Acquired Infection
HAI Hemagglutination Inhibition (Immune assay type, microbiology) ) antibody titers antibody titer The amount of a specific antibody present in the serum, usually as a result of an acquired infection; titers for IgM usually rise abruptly at the time of infection–acute phase and fall slowly; during the 'convalescent' phase, IgG ↑ and is of 1:40-1:80, consistent with recent infections. The new influenza strain had been independently identified in 3 different laboratories and supporting serologic se·rol·o·gy
n. pl. se·rol·o·gies
1. The science that deals with the properties and reactions of serums, especially blood serum.
2. evidence developed within 15 days after the original specimens were collected (Table) (4).
Swine Influenza A Viruses
The swine influenza A (Hsw1N1) viruses from Fort Dix soldiers were studied at CDC (5,6). The novel virus was named A/New Jersey/76 (Hsw1N1). Initially, HAI serologic studies of Fort Dix populations were performed at WRAIR by using inactivated inactivated
rendered inactive; the activity is destroyed.
treated so that they are no longer able to produce evidence of growth or damaging effect on tissue. A/Mayo Clinic/103/74 (Hsw1N1) antigen from CDC (7). The A/Mayo Clinic virus was recovered in 1974 from lung tissue obtained at autopsy from a man with Hodgkin disease Hodgkin disease
Most common malignant lymphoma. It starts with local, painless swelling of lymph nodes and sometimes of the spleen, liver, or other organs, followed by weight loss and weakness. who lived on a swine swine, name for any of the cloven-hoofed mammals of the family Suidae, native to the Old World. A swine has a rather long, mobile snout, a heavy, relatively short-legged body, a thick, bristly hide, and a small tail. farm (8). Later, CDC provided WRAIR with A/New Jersey/76 (Hsw1N1) antigen (7).
Outbreak Investigation Planning
Outbreak investigation plans were developed quickly, and lines of communication "Lines of Communication" is an episode from the fourth season of the science-fiction television series Babylon 5. Synopsis
Franklin and Marcus attempt to persuade the Mars resistance to assist Sheridan in opposing President Clark. and responsibilities were defined. Since a retrospective investigation required extensive serologic studies, a serology Serology
The division of biological science concerned with antigen-antibody reactions in serum. It properly encompasses any of these reactions, but is often used in a limited sense to denote laboratory diagnostic tests, especially for syphilis. laboratory was established at WRAIR and operated 7 days a week. The HAI antibody test, which measured antibody to the hemagglutinin hemagglutinin /he·mag·glu·ti·nin/ (-gloo´ti-nin) an antibody that causes agglutination of erythrocytes.
cold hemagglutinin one which acts only at temperatures near 4° C. glycoprotein glycoprotein (glī'kōprō`tēn), organic compound composed of both a protein and a carbohydrate joined together in covalent chemical linkage. , was used to identify infections (9). Variables other than 1976 swine virus infection that might influence HAI titers were identified. Influenza A (H1N1) viruses circulated from 1918 to 1957 (3). Additionally, earlier military influenza vaccines (1955-1969) and some civilian formulations (1956-1958) contained swine antigens (10). Most basic training soldiers were in their late teens and early twenties, so few had potential exposure to military vaccines (the earlier military vaccines were available to civilian workers and soldiers' families) (10). Other populations were expected to have age-related antibody from infections or vaccines. Development of heterotypic heterotypic /het·ero·typ·ic/ (-tip´ik) pertaining to, characteristic of, or belonging to a different type.
het·er·o·typ·ic or het·er·o·typ·i·cal
adj. antibody after vaccination or infection with contemporary H3N2 antigens was possible; populations suitable for assessing this were studied. None of the potential HAI test limitations was considered serious.
The NJ Department of Health continued to provide virus isolation services to the military (4). Army personnel investigated the outbreak on Fort Dix; civilian health departments defined the outbreak beyond Fort Dix. CDC provided reference laboratory support and consultation.
Case Finding at Fort Dix
Case-finding was conducted prospectively and retrospectively (Table). Prospectively, throat washings were collected from patients with febrile, acute respiratory disease who were hospitalized or sought treatment at the emergency room February 14-16 (phase I, n = 50) and February 22-24 (phase II, n = 45) (7). Attempts were made to obtain paired serum specimens from phase I patients. Specimens were obtained from 60 basic training soldiers, 13 other military personnel, and 22 civilians. A/Victoria/75 (H3N2) virus was isolated from 34 (68%) persons during phase I and 21 (47%) in phase II (7). A/New Jersey/76 (Hsw1N1) was not isolated from any of the 95 patients. One of 34 (3%) persons with an A/Victoria isolate and paired serum samples had a [greater than or equal to] 4-fold rise in titer titer /ti·ter/ (ti´ter) the quantity of a substance required to react with or to correspond to a given amount of another substance. to A/Mayo Clinic (Hsw1N1) antigen, with an acute titer of <1:10 increasing to 1:20 (7).
Retrospective study retrospective study,
a study in which a search is made for a relationship between one phenomenon or condition and another that occurred in the past (e.g. was made possible by an ongoing Adenovirus Surveillance Program, which collected weekly throats swabs and paired serum specimens from a sample ([approximately equal to] 3%-6%) of basic trainees hospitalized with respiratory disease (7). Specimens had been sent to Army regional laboratories, and 80% of the paired serum specimens from Fort Dix trainees hospitalized between November 1, 1975, and February 14, 1976, went to Fort Meade, Maryland Fort Meade is a census-designated place (CDP) in Anne Arundel County, Maryland, United States. The population was 9,882 at the 2000 census. It is the home to the National Security Agency in the US Army base of the same name. . Serum specimens not depleted de·plete
tr.v. de·plet·ed, de·plet·ing, de·pletes
To decrease the fullness of; use up or empty out.
[Latin d by routine studies were stored. Stored serum specimens from 74 Fort Dix trainees were identified at Fort Meade and forwarded to WRAIR; 39 (53%) of the trainees had been hospitalized after January 1, 1976. These serum samples were initially tested against A/Mayo Clinic antigen. Serum samples with [greater than or equal to] 4-fold rises in titer were re-tested against A/New Jersey and A/Victoria/3/75 (H3N2) antigens (7). HAI titers to A/Mayo Clinic and A/New Jersey differed only slightly.
Concerns that influenza A (H3N2) infection or vaccination might stimulate antibody to A/Mayo Clinic were addressed. Four groups were studied to identify persons with [greater than or equal to] 4-fold heterotypic HAI antibody increases to A/Mayo Clinic. None were found in 39 Fort Dix soldiers who received influenza vaccine in February 1976 (group 1), and none were found among 27 hospitalized soldiers from posts other than Fort Dix who had [greater than or equal to] 4-fold rises in complement fixation complement fixation
The binding of active complement to a specific antigen-antibody pair used in diagnostic tests, such as the Wasserman test, to detect the presence of a specific antigen or antibody. (CF) antibody to influenza A (group 2) (7). In the third group, [greater than or equal to] 4-fold rises in antibody titers developed in 3 (8%) of 40 soldiers from Fort Dix and elsewhere who had been hospitalized with an A/Victoria isolate (7). In the fourth group, a single serum sample was studied from each of 168 randomly selected Fort Dix basic trainees who had received their annual influenza vaccination 3 to 4 weeks earlier (11). Only 4 (2%) had HAI titers [greater than or equal to] 1:20 to A/Mayo Clinic (11). In similar studies by others, in 0%-6% of persons, heterotypic antibody to influenza A/swine developed after infection with A/Victoria (H3N2) or influenza vaccination (12,13).
Since heterotypic antibody to A/Mayo Clinic seldom occurred, soldiers who were hospitalized for acute respiratory disease and showed a [greater than or equal to] 4-fold titer rise to influenza A (Hsw1N1) in stored serum specimens from the Adenovirus Surveillance Program were considered to have had A/New Jersey infections. Eight new cases in basic trainees were found. Three (38%) of the 8 solders also had [greater than or equal to] 4-fold antibody rises to A/Victoria. Therefore, 13 male, enlisted soldiers, aged 17-21 years, were identified as having had respiratory diseases resulting in hospitalization hospitalization /hos·pi·tal·iza·tion/ (hos?pi-t'l-i-za´shun)
1. the placing of a patient in a hospital for treatment.
2. the term of confinement in a hospital. or death and an A/New Jersey (Hsw1N1) isolate or serologic conversion to A/New Jersey (case-patients). Ten had arrived at Fort Dix between January 5 and February 3, 1976. Three arrived between September 9 and December 30, 1975. Dates of onset of illness were known for 12 and were from January 12 to February 8, 1976. Hospital admissions occurred between January 19 and February 9. Autopsy findings for the only patient who died showed severe edema edema (ĭdē`mə), abnormal accumulation of fluid in the body tissues or in the body cavities causing swelling or distention of the affected parts. , hemorrhage hemorrhage (hĕm`ərĭj), escape of blood from the circulation (arteries, veins, capillaries) to the internal or external tissues. The term is usually applied to a loss of blood that is copious enough to threaten health or life. , and mononuclear mononuclear /mono·nu·cle·ar/ (-noo´kle-er)
1. having but one nucleus.
2. a cell having a single nucleus, especially a monocyte of the blood or tissues.
adj. infiltrates Infiltrates
Cells or body fluids that have passed into a tissue or body cavity.
Mentioned in: Eosinophilic Pneumonia in the lungs, consistent with viral pneumonia viral pneumonia Pulmonology Pneumonia of viral origin, which is more severe in the very young and very old Common pathogens Adenovirus, influenza virus, parainfluenza virus, RSV, rhinovirus, HS, CMV. See Influenza, Pneumonia, Respiratory syncytial virus. . No preexisting pre·ex·ist or pre-ex·ist
v. pre·ex·ist·ed, pre·ex·ist·ing, pre·ex·ists
To exist before (something); precede: Dinosaurs preexisted humans.
v.intr. disease or bacterial infection was found. Four (33%) of the 12 surviving patients had radiologic radiologic Radiological adjective Referring to radiology evidence of pneumonia but their clinical syndromes were similar to those described for patients with infections caused by other influenza A strains (7).
Twelve of the 13 patients were basic trainees; one was an office worker who had an A/New Jersey isolate (7). The 12 trainees were in 9 different training companies (7,14). One company had 3 patients, and 1 company had 2 patients. In these 2 companies, all patients came from the same platoon. Nine were interviewed. Except for those in the same unit, the patients were unknown to each other. All denied swine contact for 6 months before admission. No common variables in working or living environments were identified. All had contact with the Fort Dix medical care system, but care took place in 5 clinics and 2 wards. From January 19 to February 9, there were 7 days when none occupied a hospital bed (7,14).
Transmission and Illness in Units with Case-patients
Transmission was assessed by using HAI antibody titers to A/Mayo Clinic (Hsw 1N1). Sixteen of 17 contacts of the patient not in basic training, 1843 years of age, were studied, and 4 (25%) had titers [greater than or equal to] 1:20 (14). One of the 9 training companies had a case-patient who completed basic training before the case was identified and was not studied. In another company with a case-patient, 13 soldiers were studied, and all had titers [greater than or equal to] 1:10, but their platoons were not identified. Seven companies were studied by comparing the platoon with at least 1 case-patient to other platoons in the company. Some members of all 7 platoons with case-patients had titers [greater than or equal to] 1:20, varying from 7% to 56% (median = 26%). In other platoons from these seven companies, the prevalence of titers [greater than or equal to] 1:20 ranged from 0% to 40% (median 18%), which indicated that A/New Jersey virus transmission was not limited to 1 platoon in most companies (14).
Comparable samples of soldiers from the 7 companies with cases discussed above and 7 contemporary companies without cases were evaluated. Prevalences of HAI antibody titers to A/Mayo Clinic [greater than or equal to] 1:20 in the companies with cases ranged from 0% to 45% (median 18%) (8). Prevalences in the companies without cases was 0%-10% (median 4%) (14).
Available records permitted the identification of hospital admissions for acute respiratory disease in 6 of the 9 companies with an A/New Jersey case. From January 19 to February 9, 1976, when the A/New Jersey patients from these companies were admitted, admission rates for acute respiratory disease of [greater than or equal to] 3.0 per 100 men per week were observed in 4 of the companies. The highest rates occurred during the week ending January 25 and ranged from 1.1 to 6.9 (median 3.4) per 100 men per week (14).
Extent of Spread and Duration of Outbreak
The weekly formation of segregated cohorts of new recruits provided an opportunity to study the extent and duration of virus transmission. A random 9% sample of soldiers beginning basic training from January 5 to March 1 were studied for HAI antibody to A/Mayo Clinic (Hsw1N1) (11). The prevalence of titers [greater than or equal to] 1:20 by weekly cohort ranged from 0% to 19%. The 3 highest prevalences, 19%, 12%, and 9%, occurred in cohorts who started training on January 12, 19, and 26, respectively. Prevalences for 6 other cohorts ranged from 0% to 5%, with 0% prevalence in the cohorts that started training on January 5 and March 1 (11). Eleven of the 12 Fort Dix basic training soldiers identified as A/New Jersey case-patients also began training on January 12, 19, and 26 (11,14).
From February 21 to February 27, a total of 39 soldiers in the basic training reception center were studied for HAI antibody to A/New Jersey (Table) (11). This same group was studied 5 weeks later. All 39 had HAI antibody titers to A/Mayo Clinic <1:10 initially and at 5 weeks. The prevalence of HAI antibody titers to A/Mayo Clinic antigen was also determined in advanced training students, civilians who visited the Fort Dix Phlebotomy Phlebotomy Definition
Phlebotomy is the act of drawing or removing blood from the circulatory system through a cut (incision) or puncture in order to obtain a sample for analysis and diagnosis. Clinic, installation maintenance workers, basic training instructors, military medical and veterinary personnel, and soldiers who worked in the reception center. In advanced training students and persons [less than or equal to] 25 years of age, the prevalence of titers [greater than or equal to] 1:20 was 0%-6%, consistent with heterotypic responses. However, titers were higher in persons [greater than or equal to] 26 years old; most had prevalences in the range of 17% to 44%, but women and men [greater than or equal to] 51 years of age at the Phlebotomy Clinic had prevalences of 92% (n = 37) and 88% (n = 60), respectively (11).
The earliest A/New Jersey patient was hospitalized on January 19; the last identified patient Identified patient (IP)
The family member in whom the family's symptom has emerged or is most obvious.
Mentioned in: Family Therapy was admitted on February 9 (Table) (7). Both were identified by serologic testing serologic test Lab medicine A test that measures components–eg, antibodies, complement, and reactions–eg, complement fixation, agglutination, precipitation, etc, that reflect immune status, especially antibody titers. Cf Seroconversion. . Four of 5 patients with virus isolates were admitted on January 29 and 30. The last A/New Jersey isolate came from the soldier who died on February 4. The patient admitted on January 19 reported that his onset of illness occurred on January 12. Since no evidence was found for A/New Jersey virus at Fort Dix before January 12, the virus was likely introduced on or shortly after resumption of training on January 5. As shown by the clustering of hospital admissions, the A/New Jersey outbreak peaked during late January and tapered ta·per
1. A small or very slender candle.
2. A long wax-coated wick used to light candles or gas lamps.
3. A source of feeble light.
a. off in early February. The absence of any indication of the A/New Jersey virus in the cohort beginning basic training on March 1 and in the reception center group who gave blood samples from February 21 to February 27 and 5 weeks later supports the conclusion that A/New Jersey disappeared in February (Table) (11).
To understand the relationship of the A/Victoria and A/New Jersey/76 (Hsw1N1) outbreaks, serum specimens from the 9% sample of soldiers who began basic training from January 5 to March 1 were also studied for HAI antibody to A/Victoria. The geometric mean (mathematics) geometric mean - The Nth root of the product of N numbers.
If each number in a list of numbers was replaced with their geometric mean, then multiplying them all together would still give the same result. titers to A/Victoria [greater than or equal to] 1:10 for cohorts beginning training on January 5 and January 12 were 1:56 and 1:53, respectively. The geometric mean titers then increased to 1:114 in the cohort that started on February 2, peaked at 1:120 in the cohort that began on February 9, remained high at 1:109 for the February 16 cohort, and then returned to baseline (11). Thus, the A/New Jersey outbreak likely started in early January and peaked in late January, followed closely by the A/Victoria outbreak.
Even though A/Mayo Clinic titers [greater than or equal to] 1:20 were seen in Fort Dix populations other than basic trainees, the prevalences in young people were very low, consistent with heterotypic antibody. Higher prevalences in older persons could have been related to earlier influenza A (H1N1) infections or vaccinations with vaccines that contained swine influenza antigens (10). The high titers to A/Mayo Clinic in these groups could not be related to illness, vaccination, or swine contact (11). When the serologic data were extrapolated, the total number of A/New Jersey infections in Fort Dix basic trainees was [approximately equal to] 230 when contacts of all 13 case-patients were considered and [approximately equal to] 142 when only virologically confirmed cases were considered true cases (11,15).
Case Finding beyond Fort Dix
Influenza A/Victoria-like strains had been identified in New Jersey as early as January 21, 1976. By the end of January, the state had investigated reports of high employee and student absenteeism ab·sen·tee·ism
1. Habitual failure to appear, especially for work or other regular duty.
2. The rate of occurrence of habitual absence from work or duty. and a hospital outbreak. Patients in all episodes were sampled by using virus isolation and serologic testing. All laboratory reports indicated A/Victoria virus infections (4).
Starting February 10, arrangements were made to study febrile respiratory disease patients at McGuire Air Force Base McGuire Air Force Base (IATA: WRI, ICAO: KWRI, FAA LID: WRI) is a United States Air Force Base located in parts of New Hanover Township and North Hanover Township, in Burlington County, New Jersey.
It is also a census-designated place. (adjoining Fort Dix) and at hospitals, emergency rooms, and physicians' offices in the Fort Dix vicinity. Medical examiners A public official charged with investigating all sudden, suspicious, unexplained, or unnatural deaths within the area of his or her appointed jurisdiction. A medical examiner differs from a Coroner in that a medical examiner is a physician. were told to obtain specimens from possible influenza patients and surveillance was increased statewide. From January 9 to March 19, infection with influenza A/Victoria virus was documented in 301 persons by virus isolation (151 persons), CF or HAI serology (113 persons), or both (37 persons). Cases in New Jersey came from 19 of 21 counties, McGuire Air Force Base, and Lakehurst Naval Training Center. Delaware had 19 cases, including 5 from Dover Air Force Base Dover Air Force Base or Dover AFB (IATA: DOV, ICAO: KDOV, FAA LID: DOV) is a base of the United States Air Force in the state of Delaware. The base is located two miles south of the city of Dover — the capital of Delaware. . From January 31 to March 17, 10 civilian deaths in New Jersey were attributed to influenza. Influenza A/Victoria (H3N2) was isolated from all 10 patients (4).
The numbers of isolation and serologic specimens tested and the percentages positive for A/Victoria were consistent with an outbreak that began quickly in January and declined in late February to early March. No influenza cases were identified after March 19; influenza A/New Jersey was never isolated outside Fort Dix (Table) (4,7).
Among patients with serologic evidence of influenza, HAI antibody responses to both A/Victoria and A/New Jersey were studied in 134. Six (4%), aged 22 to 71 years, had [greater than or equal to] 4-fold HAI rises in titer to both viruses (4). In the absence of any association with swine influenza A virus, the A/New Jersey titers were attributed to A/Victoria infections.
Summary and Speculation
A/New Jersey/76 (Hsw1N1) was likely introduced into Fort Dix early in 1976, after the holidays (15). The virus caused disease with radiologic evidence of pneumonia in at least 4 soldiers and 1 death; all of these patients had previously been healthy (7,15). The virus was transmitted to close contacts in the unique basic training environment, with limited transmission outside the basic training group. A/New Jersey probably circulated for a month and disappeared. The source of the virus, the exact time of its introduction into Fort Dix, and factors limiting its spread and duration are unknown (15).
The Fort Dix outbreak may have been a zoonotic Zoonotic
A disease which can be spread from animals to humans.
Mentioned in: Zoonosis anomaly caused by introduction of an animal virus into a stressed population in close contact in crowded facilities during a cold winter. However, the impact of A/New Jersey virus on this healthy young population was severe in terms of estimated infections, hospitalizations, and duration of the outbreak.
If the outbreak was more than an anomaly, why did it not extend beyond basic trainees? Several factors merit consideration. Contact between basic trainees and others was limited. Moreover, a swine influenza antigen was included in annual military influenza vaccine formulations from 1955 through 1969 (10). The high antibody titers to A/Mayo Clinic antigen observed with increasing age in the Phlebotomy Clinic population may reflect earlier influenza A (H1N1) infections or vaccine exposure and some protection (11). Also, competition between A/New Jersey and A/Victoria viruses must be considered. The A/Victoria virus spread widely and may have limited the impact of A/New Jersey virus with its lesser ability for human transmission.
Could the Fort Dix outbreak have resulted from interaction between swine influenza A and A/Victoria viruses? A/Victoria transmission occurred in New Jersey before A/New Jersey was identified at Fort Dix. Is it possible that A/Victoria virus and an early A/New Jersey virus coinfected a soldier with genetic exchange, resulting in a recombinant virus with enhanced human transmission capability? The rapid disappearance of A/New Jersey prohibited studies of virus interactions. Genetic analyses of A/New Jersey, A/Victoria and contemporary A/swine viruses might elucidate e·lu·ci·date
v. e·lu·ci·dat·ed, e·lu·ci·dat·ing, e·lu·ci·dates
To make clear or plain, especially by explanation; clarify.
To give an explanation that serves to clarify. a relationship.
Communication and collaboration existed at the onset of the outbreak and continued throughout the investigation. The points of contact at the NJ Department of Health, Fort Dix, CDC, and WRAIR had been established before the outbreak, so time was not lost identifying organizations and persons who needed to be contacted. Organizational roles were defined early and respected. The development of outbreak investigation plans, collaboration in field and laboratory work, and exchange of information occurred smoothly. An important part of the Army investigation was establishment of points of contact at WRAIR who communicated with military leaders, the NJ Department of Health, CDC, and the press. Military epidemiology and laboratory teams reported to WRAIR points of contact. This system protected these teams from disruptive inquiries.
The burden on the laboratories supporting this investigation was intense, lasting for weeks. In 1976, WRAIR was a research and field epidemiology laboratory that also operated as a public health reference laboratory. The WRAIR commander had the authority to reallocate Verb 1. reallocate - allocate, distribute, or apportion anew; "Congressional seats are reapportioned on the basis of census data"
allocate, apportion - distribute according to a plan or set apart for a special purpose; "I am allocating a loaf of and mobilize scientists and laboratory resources. Today, WRAIR no longer functions as a public health laboratory. The depth of resources and flexibility that existed at WRAIR in 1976 cannot be found in other military laboratories (16). Duplicating the 1976 laboratory effort today, in timely fashion, would be difficult.
The investigation of the Fort Dix swine influenza A outbreak in 1976 was made possible by the competence, professionalism, and hard work of many persons from the New Jersey Department of Health; Fort Dix, NJ, US Army Medical Department Activity; WRAIR; CDC; and others. We acknowledge all of them, wherever they may be, with gratitude for their outstanding contributions.
(1.) Centers for Disease Control and Prevention Centers for Disease Control and Prevention (CDC), agency of the U.S. Public Health Service since 1973, with headquarters in Atlanta; it was established in 1946 as the Communicable Disease Center. . Update: influenza activity--United States and worldwide. 2004 05 season. MMWR MMWR Morbidity & Mortality Weekly Report Epidemiology A news bulletin published by the CDC, which provides epidemiologic data–eg, statistics on the incidence of AIDS, rabies, rubella, STDs and other communicable diseases, causes of mortality–eg, Morb Mortal Wkly Rep. 2005;54:631-4.
(2.) Crosby AW. Epidemic and peace, 1918. Westport (CT): Greenwood Press: 1976.
(3.) Cox NJ, Fukuda K. Influenza. Infect infect /in·fect/ (in-fekt´)
1. to invade and produce infection in.
2. to transmit a pathogen or disease to.
1. Dis Clin North Am. 1998;12:27 38.
(4.) Goldfield Goldfield, small town, SW Nev., a former gold-mining center. Gold was discovered there in 1902, and after an early period of disappointment, large yields of high quality gold were extracted. M, Bartley JD, Pizzuti W, Black HC, Altman R, Halperin WE. Influenza in New Jersey in 1976: isolations of influenza A/New Jersey/76 virus at Fort Dix. J Infect Dis. 1977;136:S347-55.
(5.) Kendal AP, Goldfield M, Noble GR. Dowdle WR. Identification and preliminary antigenic analysis of swine influenza-like viruses isolated during an influenza outbreak at Fort Dix, New Jersey. J Infect Dis. 1977;136:S381-5.
(6.) Kendal AR Noble GR, Dowdle WR. Swine influenza viruses isolated in 1976 from man and pig contain two coexisting co·ex·ist
intr.v. co·ex·ist·ed, co·ex·ist·ing, co·ex·ists
1. To exist together, at the same time, or in the same place.
2. subpopulations with antigenically distinguishable hemaggltuinins. 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 . 1977;82:111-21.
(7.) Gaydos JC. Hodder RA, Top FH Jr, Soden VJ, Allen RG, Bartley JD, et al. Swine influenza A at Fort Dix, New Jersey (January February 1976). I. Case finding and clinical study of cases. J Infect Dis. 1977;136:S356-62.
(8.) Smith TF, Burgert EO Jr, Dowdle WR, Noble GR, Campbell RJ, Van Scoy RE. Isolation of swine influenza virus from autopsy lung tissue of man. N Engl J Med. 1976;294:708 10.
(9.) Treanor JJ. King JC, Zangwill KM. New approaches to influenza vaccine in new generation vaccines. 3rd ed. New York New York, state, United States
New York, Middle Atlantic state of the United States. It is bordered by Vermont, Massachusetts, Connecticut, and the Atlantic Ocean (E), New Jersey and Pennsylvania (S), Lakes Erie and Ontario and the Canadian province of : Marcel Dekker Marcel Dekker is a well-known encyclopedia publishing company with editorial boards found in New York, New York. They are part of the Taylor and Francis publishing group.
Initially a textbook publisher, they went to encyclopedia publishing in the late 1990's. ; 2004:537-58.
(10.) Takafuji ET, Johnson DE, Segal HE. The swine antigen in previous influenza vaccines. N Engl J Med. 1976;295:1018.
(11.) Hodder RA, Gaydos JC, Allen RG, Top FH Jr, Nowosiwsky T, Russell PK. Swine influenza A at Fort Dix, New Jersey (January-February 1976). III. Extent of spread and duration of the outbreak. J Infect Dis. 1977;136:S369-75.
(12.) Masurel N. Swine influenza virus and the recycling of influenza-A viruses in man. Lancet. 1976;2:244-7.
(13.) Noble GR, Kaye HS, Kendal AP, Dowdle WR. Age-related heterologous heterologous /het·er·ol·o·gous/ (het?er-ol´ah-gus)
1. made up of tissue not normal to the part.
1. antibody responses to influenza virus vaccination. J Infect Dis. 1977;136:S686-92.
(14.) Gaydos JC, Hodder RA, Top FH Jr, Allen RG, Soden VJ, Nowosiwsky T, et al. Swine influenza A at Fort Dix, New Jersey (January-February 1976). II. Transmission and morbidity in units with cases. J Infect Dis. 1977;136:S363-8.
(15.) Top FH Jr, Russell PK. Swine influenza A at Fort Dix, New Jersey (January-February 1976). IV. Summary and speculation. J Infect Dis. 1977:136:S376 80.
(16.) Gaydos JC. The need for a military public health laboratory symposium. Mil Med. 2000:165:5-7.
Address for correspondence: Joel C. Gaydos, US Department of Defense Global Emerging Infections Surveillance and Response System, Waiter Reed Army Institute of Research, Silver Spring, MD 20910-7500, USA;. tax: 301-319-9213: email: Joel.Gaydos@na.amedd.army.mil.
Joel C. Gaydos, * Franklin H. Top, Jr, ([dagger]) Richard A. Hodder, ([double dagger double dagger
A reference mark () used in printing and writing. Also called diesis.
Noun 1. ]) and Philip K. Russel ([section]) (1)
* Walter Reed Army Institute of Research, Silver Spring, Maryland Not to be confused with Silver Springs.
Silver Spring is an urbanized, unincorporated area in Montgomery County, Maryland, USA. After Baltimore and Columbia, Silver Spring is the third most populous Census Designated Place in Maryland. , USA; ([dagger]) MedImmune, Incorporated, Gaithersburg, Maryland, USA; ([double dagger]) Northeast Center for Special Care, Lake Katrine, New York Lake Katrine is a hamlet (and census-designated place) in Ulster County, New York, United States. The population was 2,396 at the 2000 census.
Lake Katrine is a community in the western part of the Town of Ulster, located near a small lake, also called Lake Katrine. , USA; and ([section]) Albert B. Sabin Vaccine Sabin vaccine
An oral vaccine that contains live attenuated polioviruses and is used to confer immunity against poliomyelitis. Institute, New Canaan, Connecticut New Canaan is a wealthy town in Fairfield County, Connecticut, United States, 8 miles (13 km) northeast of Stamford, on the Five Mile River. In 1900, 2,968 people lived in New Canaan, and in 1910, 3,667. The population was 19,395 at the 2000 census. , USA
(1) In 1976 all authors were US Army officers assigned to the Walter Reed Army Institute of Research, Washington, DC.
Dr Gaydos is director, Public Health Practices, for the US Department of Defense Global Emerging infections Surveillance and Response System. His research interests include acute respiratory diseases in previously healthy persons and sexually transmitted infections.
Table. Key events in the swine influenza A (Hsw1N1) outbreak, Fort Dix, NJ Date (1976) Event January 5 Outbreak of acute respiratory disease following influx of new recruit trainees (4). January 19 Earliest hospitalization of Fort Dix soldier with acute respiratory disease attributed to swine influenza A (Hsw1N1) (identified retrospectively by serologic tests) (7,14) January 21 Influenza A/Victoria (H3N2) identified away from Fort Dix in NJ civilians (4) January 23 Adenovirus type 21 isolated from soldiers ill with respiratory disease: Fort Dix reported outbreak to local and state health departments (4) January 28 NJ Department of Health (DoH) suggested Fort Dix outbreak may be due to influenza and offered to process specimens for virus isolation (4) January 29-30 19 specimens sent to NJ Department of Health in 2 shipments (4) February 2-3 NJ DoH identified 4 isolates of H3N2-like viruses and 2 unknown hemagglutinating agents in 8 specimens sent on January 29. Fort Dix and NJ DoH arranged for study of deaths possibly due to influenza. NJ DoH identified 3 H3N2-like viruses and third unknown hemagglutinating agent in 11 specimens sent on January 30 (4). February 4 Fort Dix soldier died with acute respiratory disease (4). February 5 Tracheal specimens from deceased soldier sent to NJ DoH (4). February 6 NJ DoH sent specimens to Center for Disease Control (CDC), Atlanta, GA; CDC identified fourth unknown hemagglutinating agent in Fort Dix specimens (4). February 9 Specimens from soldier who died on February 4 yielded fifth unknown hemagglutinating agent (4). Last hospitalization of an identified Fort Dix soldier with febrile, acute respiratory disease attributed to swine influenza A (Hsw1N1) (identified retrospectively by serologic tests) (7,14). February 10 Laboratory evidence supported 2 influenza type A strains circulating on Fort Dix; 1 was a radically new strain. Prospective surveillance for cases in surrounding area was initiated, only cases of H3N2 were found (4). February 13 Review of laboratory data and information found all 5 unknown agents were swine influenza A strains (later named A/New Jersey [Hsw1N1]); 3 laboratories independently identified swine virus from original specimens (serologic data supporting swine influenza A virus infection later obtained from 2 survivors with A/New Jersey isolates) (4). February 14-16 Initial planning meeting in Atlanta, GA, between CDC, NJ DoH, Fort Dix, and Walter Reed Army Institute of Research personnel. Prospective case finding was initiated at Fort Dix; H3N2 was isolated; Hsw1N1 was not isolated (7). Retrospective case finding was initiated by serologic study of stored serum specimens from Fort Dix soldiers who had been hospitalized for acute respiratory disease; 8 new cases of disease due to Hsw1N1 were identified with hospitalization dates between January 19 and February 9 (7,14). February 22-24 Prospective case finding was again conducted at Fort Dix; H3N2 virus was isolated but not Hsw1N1 (7). February 27 Thirty-nine new recruits entering Fort Dix February 21-27 gave blood samples after arrival and 5 weeks later; serologic studies were consistent with influenza immunization but not spread of H3N2 virus. None had titer rise to Hsw1N1 (11). March 19 Prospective surveillance identified last case of influenza in areas around Fort Dix; only H3N2 viruses were identified outside of Fort Dix (4).