The Changing Faces of Quarantine
The concept and the mission of quarantine have always been to prevent the importation and spread of disease and to protect populations from contagious disease. The roots of quarantine go way back. In the book of Leviticus in the Old Testament you can find reference to the principles of quarantine, a description of a practice of isolating persons afflicted with leprosy, a sort of prescribed isolation. Back in the fourteenth century in Europe, when plague, then called the "Black Death," was moving through, there were very drastic measures imposed on commerce in Italy to prevent the spread of the Black Death from moving from country to country via the seaports. The actual formal process of quarantine was pioneered in Venice. In 1348, there was a system for treating infected ships, travelers and merchandise. Venice's example was followed by other city-states at the time. In Ragussa, a landing station was established that was removed from the city for a thirty day detention period. This was known as trentina in Latin, or thirty days. In 1485, Venice established the forty-day harbor detention process, quarantina in Latin, or quarantine, and this is the first official use of "quarantine." In 1626, in Marseille, the first quarantine station was formed, and they introduced the official bill of health, the landing that certified that this ship coming into port was a healthy vessel. Following the plague epidemic in London in 1664, England passed some rigorous quarantine acts, and as late as 1721, ships coming from infected areas were burned in English waters. Now that is a pretty severe way to deal with preventing importation and spread. All quarantined vessels that were en route to England were required to show a solid yellow flag to indicate that they were under quarantine, and this became known as the "Q" flag. This flag is still represented on the quarantine station's officer's uniform today. If you go to the Seattle quarantine station at Sea-Tac, you can see the yellow flag. It also became known in the international maritime code of flag signals, the yellow quarantine flag.
Shifting over to the New World, in colonial America, quarantine was always handled as a local matter by individual colonies. The earliest evidence of quarantine was in the Massachusetts Bay Colony in 1647. This was implemented because of plague in the West Indies. But this was very much a local jurisdiction, interwoven immensely with commerce. Vessels from the West Indies were forbidden to land or discharge passengers or cargo during this plague outbreak. In Philadelphia, there was a yellow fever outbreak in 1699, and they passed a quarantine act to bar unhealthy or sickly vessels from coming closer than one mile from land without a certified bill of health and a permit.
In 1870 to 1920, we had a large wave of immigration, "the third wave." The last group, from 1898 to 1920, was mostly Eastern Europeans and very poor. These were in contrast to the earlier waves of immigration in the 1800s, which were wealthier Western Europeans. The Western Europeans were often coming here for economic opportunity rather than being driven out of Eastern Europe and Russia by czarist practices. The poor that came in this third wave of immigration were often crammed densely onto large vessels traveling across the ocean. These ships became the sources of outbreaks of disease. There was a large typhus epidemic in 1892 on one of these immigration vessels, the Febre Line steamer Massilia. There was also a large cholera epidemic in New York City in 1892. These epidemics became interwoven into the perception of this newly arriving immigrant population from the more established and affluent western Europeans as "dirty" and "tainted." They were fearful of the arrival of this new group and the disease that they were going to bring with them. In many ways, the quarantine was used as a political tool to exclude people and to try to prevent the infusion of the lower class into what they perceived as a prospering new America.
In 1878, the National Quarantine Act was signed. The Act began to shift quarantine authority and quarantine powers away from the states and put it into the hands of a federal entity. The Public Health Service Act was signed in 1944, and it created the extension of the maritime health service. These two things became interwoven very clearly into the major responsibilities of quarantine. The maritime health entities established the public health service hospitals in many poor coastal areas of the United States. These facilities were designed to provide healthcare service to people who did not really have a land-based home state. The immigrants were mobile and on the move. If you were a seaman, and you were arriving at a new port of call and had illness, you were entitled through the public health service to receive treatment at one of these hospitals at no charge. In fact, one of the public health service hospitals was right here in Seattle (formerly Pacific Medical Center, now Amazon.com).
In 1895, as part of this concept of "decontaminating" immigrants, it was quite common to have a disinfection process for baggage and clothing, and even a set of shower stalls in which people went in and often were sprayed with disinfectant. The Public Health Service (PHS) regulation calls for the medical examination of all newly arriving Americans. The following are the communicable diseases of public health significance that were screened for in newly arriving Americans: infectious TB, syphilis, chancroid, gonorrhea, granuloma inguinale, LGV and leprosy. In the older days of quarantine, this medical assessment of newly arriving Americans, or aliens, was done at the ports of entry, and there were many quarantine stations, scattered throughout the portals in the United States. Another responsibility of the quarantine officer was to assess illness aboard internationally arriving ships. They would often board a ship to inspect and make a sanitary assessment. If there was a febrile patient and there was a concern that there might be communicable disease on board, they would do a medical assessment and a determination of whether that person needed to remain in isolation.
Around 1944, the home for quarantine in the federal government was in the Department of Treasury, commensurate with its earlier roots in promoting international commerce with promoting and protecting free trade. It was to identify sick vessels that were then not allowed to enter the harbor and restricted from participation in international commerce. As more public health functions were attributed to Quarantine, its evolution was in concert. The Quarantine Division was moved from the Treasury Department to the Department of Health Education and Welfare (DHEW), which later became known as the Department of Health and Human Services (DHHS). In 1967, the Division of Foreign Quarantine was transferred to the Centers for Disease Control (CDC).
The International Health Regulations (IHRs) constitute a legal international treaty signed by a number of countries. The IHRs include a requirement on the part of its signatures to report certain diseases to the World Health Organization (WHO). The three quarantinable diseases that require reporting as stipulated by IHRs include yellow fever, plague and cholera; however each individual country has the sovereignty to specify its own quarantinable disease list beyond these 3 conditions. In 1982, by Executive Order of President Reagan, the list of US diseases included under foreign quarantine code of federal regulations was modified to include: yellow fever, plague, cholera, suspected smallpox / smallpox, diphtheria, infectious tuberculosis, and the viral hemorrhagic fevers. The International Health Regulations also require member countries to provide vessel inspection services and information to prospective travelers about the international health requirements and requirements for international travel. The Division of Quarantine is delegated the authority and the responsibility of informing the US public about the requirements for international travel, including yellow fever vaccination requirements around the world. In 1977, the responsibility for certifying yellow fever vaccination centers was delegated from the CDC Division of Quarantine to the state health departments in each of the states.
I want to share with you some of my perceptions on preventing importation and spread of infectious diseases as we enter the Year 2000 and how that impacts the evolution of quarantine practice and policy. The speed and volume of international travel has reached shocking proportions. As a global population, we are on the move in unprecedented, numbers as we approach this new millennium. International air arrivals are rapidly approaching the one billion mark. Seven million North Americans are likely to take cruise ship vacations in this coming year. As many as 50 million refugees and internally displaced persons are migrating by land, moving from one place to another. We have truly become a global village. I like this quote from a report from the Institute of Medicine that says, "As the human immunodeficiency virus epidemic surely should have taught us, in the context of infectious disease, there is nowhere in the world from which we are remote, no one from whom we are disconnected."
Map - Unexpected Outbreaks This is a map from a recent WHO report called Removing Obstacles to Healthy Development, and it shows in the last five years the location of unexpected outbreaks and emerging infections that have occurred. Some of the highlights recently have included new strains of influenza virus, H9N2 and H5N1, and Nipah virus.
In the 1950's people traveled the globe largely by ship; circumnavigating the globe required 365 days. If anyone was ill in transit they either died or recovered from the disease by the time they reached their port of call. As we approach the year 2000 it only takes 36 hours to travel around the world. You can go from any one point on the globe to any other in 36 to 72 hours, depending on your connections. That means from Kikwit, Zaire to New York City takes less time than the incubation period for most infectious diseases. These diseases are no longer going to occur primarily in transit. They are going to appear after arrival, and not necessarily while you are at the port.
The other thing that has exploded is the world population. The world population is currently at 6 billion people. Of those 6 billion people, more and more of them are engaged in international journeys. The latest number I have seen is over one billion international arrivals a year. That translates into somewhere between two and three million people on international flights every day.
A wonderful article in the October 1998 issue of National Geographic called "Human Migration" by Michael Parfit, describes the process, the means, and purpose of human migration as a "dynamic undertow of population change: everyone's solution and everyone's conflict." Human migration is best seen in the context of "push" factors and "pull" factors. If you are lucky, it is a pull of economic opportunity and better things to come, or the pleasure of a new journey that motivates your journey. On the other hand, there are the push factors. There are civil wars, hardship, famine, violence and persecution that force people to leave their homes.
International movement can be viewed in three clearly distinct categories.
Over the past few years we have had imported cases of dengue from the Caribbean, Central America and Asia, schistosomiasis from outbreaks attributed to Lake Malawi and other endemic areas, Cyclospora from Nepal and Guatemala, leptospirosis in Costa Rican river rafters, and imported cases of yellow fever from Brazil and Venezuela.
Larger cruise ships can hold almost 5,000 passengers and 2,000 crew members. This is a floating city. This cruise ship is a very unique environment and is densely populated. In this floating city, you have the mixture of crewmembers and travelers from different parts of the world. Many of the crew may come from places that may not have routine immunization policies. The susceptibility profile for measles and chicken pox and other diseases are quite different than they would be in a US population that receives childhood vaccines. The passengers on this ship, on the other hand, are frequently elderly, mostly North American, often with underlying chronic health conditions that place them at increased risk for certain conditions. There are also some physical and environmental features that contribute to the emergence of disease. This industry has grown tremendously, perhaps more than doubled in volume of passengers over the last decade and also increased the number of ports of call they make. In 1994, an outbreak investigation of pneumonia was linked to inhalation of aerosolized bacteria from the whirlpool spas. The organism recovered was Legionella pneumophila.
Emerging infections in travelers can frequently go undetected for long periods of time. One reason is the population's mobility, for example after a cruise the passenger scatter quickly. It can be difficult to put all the pieces of the puzzle together when one only hears about a case here or there- the geographic clustering is not as obvious. People come from all over the world and converge for an intense, short period of time, on average 6 to 7 days, on a ship with the unique environment. They live and eat together and form a temporary community for short periods of time and then they go home and scatter, often to places all over the world. In the context of disease, that 7 days is about 2 incubation periods for many infectious diseases. You could have a single case, or multiple cases, in the embarking population. Put them on a cruise ship and the numbers can multiply quickly and also disseminate when people go back home. The other analogy is that of the Internet, where people come together in a chat room for a short period of time from all over the world, they have an intense exchange of communication, they send files or whatever back and forth, and then they go back to their own places in their own communities. I do not know if any of you have ever had an Internet virus sent to you on your computer, but you can see how quickly these viruses can spread around the globe. The analogies of a "virtual community" to those at sea are remarkably similar.
In summer 1997, we were asked to investigate an outbreak of respiratory disease on a ship that was sailing between Montreal and New York City. The ship had 75% of its passengers over 65 years of age. Another 25% of them had underlying chronic health conditions, placing them at risk for respiratory disease. Several were hospitalized with pneumonia on arrival of this cruise in Canada, and we were called and asked, could this be legionnaire's disease? We got on board to investigate, and it turns out that this was influenza-A infection in the summertime, which was quite unusual. As a matter of fact, the strain of influenza-A had not really been reported in North America before. It was a strain that, subsequently, has become known as the Sydney strain of influenza-A. When you investigate more thoroughly the cases in this epidemic curve, in the first few days of the outbreak, Australian passengers were disproportionately infected and ill with disease. It turns out there was a group of travelers that arrived from Sydney, Australia in the middle of their winter time during a big outbreak of flu in Sydney, they came to the US during our summertime. The Australian passengers infected each other; then flu spread to other passengers and crew members. Since crew members stay on board from cruise to cruise while the passenger pool cycles every week they served as a reservoir for transmission of this disease to newly boarding passengers. We were able to implement institutional control measures--use of anti-viral medication both for treatment and for prophylaxis, isolating ill people and immunizing the entire crew with influenza vaccination. These measures effectively stopped this outbreak. But that was not before the passengers from the first two cruises returned home to different destinations in the United States. This was the first reported introduction of Sydney strain flu into North America. Undoubtedly, it was not the only introduction, but you can see how effective this amplifier and disseminator could be in rapidly spreading flu strains.
The following summer in Alaska, we received reports from several vessels of outbreaks of respiratory disease. We set up a large field team to investigate in Anchorage at the CDC Arctic Investigation Program. After setting up surveillance on 17 ships that were sailing the route between Vancouver BC and Seward, Alaska and 15 land-based clinics, it was clear that there was a massive outbreak of influenza A among Alaskan tourists. This turned out to be the same strain that we saw on the earlier ship. This was A-Sydney strain flu. Of all the isolates that we collected in our surveillance system, every one of them that was influenza-A typed out as Sydney flu.
It is not just flu that has been spread on ships. In 1991, an Asian vessel that had contaminated water in its bilge, discharged this wastewater off the coast of Peru, infecting the seafood bed, which led to an enormous outbreak of cholera in Latin America. In 1991 through 1996, 655,000 cases of cholera were detected. In less developed countries, this disease can spread quite rapidly through contamination of water supplies. There was a rapid increase in cholera cases in the US reported here after the 1991 outbreak in Peru. One person returning from an area where cholera was epidemic, smuggled crabs in his suitcase back to the US and made ceviche for his friends; this resulted in a small outbreak of cholera. International commerce and globalization of the food supply are major factors in the emergence of new disease. A colleague of mine once said "You don't have to travel to get traveler's diarrhea anymore. A trip to the local grocery store is probably sufficient." We are eating from a global grocery basket, and the hygiene practices and food handling practices around the world will impact us all.
Let us move from ships to airplanes. Map - International Arrivals by Air This shows the increase in volume of international arrivals by air along popular routes. Most routes have experienced at least a 27% increase from 1993 to 1997, and the largest increases are in destinations to the least developed countries in Africa and the Middle East. As a result of so many people on airplanes, the questions that always arise are: "What can I get from sitting on that airplane? How good is the air on the airplane? Am I likely to suffer from the spread of a variety of diseases?" The CDC has been involved in seven investigations of potential transmission of TB in aircraft. All the index cases were highly infectious. Two of these investigations found evidence of transmission, one from flight attendants to other crew, and one from passenger to passenger. Transmission was associated with flight durations longer than eight hours and close proximity to a TB case, but transmission was not associated with re-circulated air. There are now guidelines that WHO and the CDC have issued for preventing TB transmission in airplanes.
Non-human primates, exotic pets, and insect vectors can all come in on
Map - Rapid Increase in Dengue Fever This graphic shows the rapid increase in cases reported to WHO of dengue from around the world over the last half century. In the Americas, dengue has been resurging for the last decade. Dengue is a viral condition spread through the bite of an infected mosquito. Map - Dengue Hemorrhagic Fever in the Americas These are some of the countries in Latin America with reported cases of dengue in 1995. Mexico in 1995 reported almost 12,000 cases of dengue and 355 cases of dengue hemorrhagic fever. Texas had a large number of cases in an outbreak on the border in 1985. The US Mexico border is probably the world's busiest frontier. There is a tremendous amount of migration in an area which is underserved in terms of public health infrastructure, hygiene, and water supply. Large migrations of populations from all of South and Central America come to the borders to work in factories. The Division of Quarantine with other partners has taken the lead in setting up a bi-national infectious disease surveillance system along the US-Mexico border called "BIDS." BIDS participants include: both federal governments, the Pan American Health Organization (PAHO), six Mexican states and their local jurisdiction, and four US State health departments and their local jurisdictions. Currently, an operational system is intensely looking at syndromic surveillance for febrile illnesses with rash, which includes testing for dengue, measles, rubella, typhus and viral hepatitis. Surveillance is occurring in nine clinics in sister-city pairs. The BIDS network was instrumental in detecting and launching an investigation of another dengue outbreak on the border in 1999 in Nuevo Laredo, Mexico and Laredo, Texas. During a household survey done by the investigation team, the percent of acute dengue cases defined by IgM sero-positivity in Mexico was 16%, and in the United States, 1.3%. But IgG sero-positivity was 50% on the Mexican side and 23% on the US side of the border. We hope the BIDS project will give us a more complete picture of febrile illnesses with rash and viral hepatitis on both sides of the US-Mexican border.
In the fall of 1999, an infectious disease physician in a hospital in Flushing, New York recognized a cluster of two cases of encephalitis and notified PH authorities. Eight more cases were identified and an investigation was initiated. Laboratory confirmed human cases of West Nile encephalitis clustered in the boroughs of Queens. Mosquito surveillance was launched as part of this outbreak investigation. Map - Lab confirmed WNV in Birds and Horses Here are lab confirmed cases in birds and in horses, birds in red and horses in blue. This outbreak is in close proximity to two international airports: LaGuardia, and JFK. It sits in the middle of a swampy flatland that serves as a habitat for mosquito breeding. These areas are a major migratory stop for migrating birds. This is the perfect mix. Queens is one of the most interesting, ethnically diverse neighborhoods in our country. Fifty five percent of Queens is foreign born and the population there speaks 40 to 50 different languages. The US Census Bureau notes that 50% of the growth of the US population in the last decade is due to the arrival of new Americans, and another 20% to their first generation offspring. So 70% of all the growth in the US population is accounted for by immigration. These demographic factors need to be taken into consideration in terms of how we establish disease surveillance.
Resettlement patterns of immigrants to the US show trends in TB cases. Our new Americans are accounting for up to 43% of all cases of tuberculosis. They are coming from a limited number of countries. Southeast Asia and Mexico account for the vast majority of TB cases among foreign born in the US The Division of TB Elimination and the Division of Quarantine have been launching major public health initiatives in Southeast Asia and in Mexico to improve the screening for tuberculosis in the foreign immigrant applicant and to foster better ways to identify and track infectious TB cases by health departments.
Mass migrations have also been associated with the emergence of infectious diseases. Troops in the Sudan were part cause of a large outbreak of dysentery. Refugees are susceptible to food and water-borne diseases, both cholera and dysentery. Interestingly even temporary migrations, like the Hajj pilgrimage to Saudi Arabia, can contribute to the spread of disease. In 1987, several cases of meningococcal meningitis were spread as a result of pilgrimages to the hajj. This pattern is likely to repeat itself with increased mobility.
Refugees are a very vulnerable population. Traditionally, the immigrant and refugee pre-departure medical assessment was restricted to infectious TB, HIV, and sexually transmitted diseases (STD). The examination has been focused on excluding people with these conditions. The concept of emerging infectious diseases and geographic migration has not really been taken into account.
In the last three years, the Division of Quarantine has been piloting projects that enhance the pre-departure health assessment of refugees. In addition to the traditional disease screening, one needs geographically tailored assessments based on the region from which people come. We piloted this assessment in Mombassa, Kenya in two refugee camps that had Barawan Somali refugees. In that pilot project, we screened 400 people for malaria, intestinal parasites and shistosomiasis. We determined the prevalence of those diseases in the refugee population based upon a representative sample, then we developed prevention / treatment algorithms based on an expected prevalence of disease. When the expected prevalence exceeds a certain threshold, it becomes less expensive (more cost-effective) to offer mass treatment than it does to selectively screen and treat. All departing Somali refugees were destined for resettlement to 36 different states in the United States. At the point of departure, all were treated with TMP/sulfa to clear malaria parasitemia, and with albendazole to clear their intestinal parasitic infections. This pilot project was very successful and has subsequently been incorporated into US policy for all departing African refugees being assessed by the International Organization for Migration. Reports of this effort will appear in the January issue of American Journal of Tropical Medicine and Hygiene. Currently, about 50% of the expected 14,000 refugees coming from Africa, (except those with contraindications) are being offered this pre-departure treatment intervention. This shows how to enhance the assessment, and to provide a preventative opportunity at a point when everybody is together, where the drugs are cheaper, and where there are translators and effective delivery mechanisms.
Some preventative therapies were implemented to enhance the refugee health assessments of Kosovar refugees. Ten thousand immunizations were provided, pre-natal care was offered, prescriptions for chronic diseases were refilled, dental problems were assessed, and lice assessments were done.
Where should quarantine be as we enter the next millennium? What should
we do to address emerging infectious diseases?
This has been a very successful partnership and network. It is operating primarily in clinics in the private sector but forms an important government-private initiative. Although it is not formally integrated into WHO member country reporting, individual clinical sites are encouraged to report their cases to appropriate local public health authorities as well as to Geosentinel. However, its success may in part be due to the freedom from political constraints on reporting by the MOH of member countries to WHO. As of December 1995 these clinics had tracked over 6,000 patients with 9,000 different final diagnoses. If the patient is seen after an international journey of any sort, they are eligible for involvement in the surveillance system. The itinerary, characteristics of the travel, and the diagnosis are recorded on a worksheet that can be faxed to the central database to build a morbidity profile. The network's patients reflect over 10,000 geographic exposures during recent international travel over the six months prior to the clinic visit.
If there is a is a three standard deviation change from the expected month by month morbidity report, it sends off a warning system in Geosentinel. Geosentinel has contributed to the emergence of regional sister networks such as TropNet Europe, which has recently detected cases of malaria in travelers to tourist areas in the Dominican Republic, traditionally areas that did not have malaria transmission. After notification of the CDC through the network, we notified the Ministry of Health in Dominican Republic and confirmed new cases of malaria transmission. An emerging infection outbreak was identified and investigated. This allowed appropriate interventions to be instituted by local health authorities. Because of the recent Caribbean hurricanes and heavy rainfall, the anopheles mosquito vector had been flourishing in areas where it had not previously been. In conjunction, there were large hotel construction projects in that area which drew temporary migrant workers from Haiti and rural areas in the Dominican, locations of endemic malaria transmission. So temporary workers brought in the parasites, the mosquito vectors were brought in by a change in the environment, and this contributed to the emergence of malaria outbreaks in the resorts. The Dominican Ministry of Health surveillance system for malaria would not have picked up the cases in temporary migrant workers or the tourists, since the Haitians were not generally receiving healthcare in local clinics within the country, and the tourists were being diagnosed only after returning to their own countries. Only surveillance of the mobile populations was effective in identifying this problem.
"The microbe that felled one child in a distant continent yesterday can reach yours today and see the global pandemic tomorrow," a quote by Dr. Joshua Lederberg. It is important for us to keep up on what is occurring worldwide and to communicate this to the rest of the world through timely surveillance information that is reported rapidly over electronic communication networks. The new yellowbook, "Health Information for International Travel," the CDC web page on travelers' health, the National Center for Infectious Disease, and the Online Journal of Emerging Infectious Disease are now all online. These are all timely sources of information from the CDC regarding emerging infections. There are many others sources as well. There is ProMed, WHO, the Weekly Epidemiologic Record, and APEC Emerging Infections Network. We need to be integrating these types of systems and communications into our modern world and certainly integrating them into the public health mainstream.
We have come a long way with respect to quarantine practice and policy in the last 150 years. Strategies to combat importation and spread of infectious disease need to adapt to our modern society of globalization and unprecedented mobility. This has required a shift in focus away from "excludable" conditions, and away from the narrow focus on the border proper; we have broadened our focus to the mobile populations that cross the border, implementing surveillance systems that keep us informed and developing strong preventative strategies to improve the health of these mobile populations.
Q: And you are always excluded entry into the US if you are HIV positive?
A: No. If you are HIV positive, you are eligible for a waiver. If you can document that you have a care provider that can manage your disease, we can recommend to the Department of State that a waiver of the restriction be administered.
Q: Cruise ship outbreaks have been happening for about 25 years. Is there any thought to putting a surveillance officer on vessels for reporting?
A: Yes, there are systems of inspection that go on routinely, a sanitation scoring system, and vessel sanitation programs have been implemented. We have been working with this industry to implement routine surveillance for respiratory diseases and have published guidelines on certain threshold levels for detecting respiratory disease outbreaks.
Freedman, Kozarsky, Weld, and Cetron for Geosentinel Study Group. "Geosentinel: the global emerging infections sentinel network of the International Society of Travel Medicine." Journal of Travel Medicine, 1999; 6: 94-98.
Cetron M, Keystone J, Shlim D, Steffen R. "Travelers' Health." Emerg Infect Dis, 1998 Jul-Sep; 4(3): 405-409.
CDC. Enhanced Medical Assessment Strategy for Barawan Somali Refugees - Kenya, 1997. MMWR, 1998; 46(52-53): 1250-1254.
Cetron MS, Chitsulo L, Sullivan JJ, Pilcher J, Wilson M, Noh J, Tsang VC, Hightower AW, Addiss DG. "Schistosomiasis in Lake Malawi." Lancet, 1996 Nov; 348: 1274-78.
CDC. Update: outbreak of Influenza A infection - Alaska and the Yukon Territory. MMWR, 1998; 47(33): 685-688.
CDC. Outbreak of Influenza A infection among travelers - Alaska and the Yukon Territory, MMWR, 1999; 48 (25): 545-6, 555.
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Send comments to Carrie Horwitch, MD, MPH
Last updated: November 2000