INTERNATIONAL SURVEILLANCE AND TRANSPORT OF EBOLA VIRUS DISEASE AND OTHER HAEMORRHAGIC FEVERS: THE UK EXPERIENCE
LILA M. ROOTS
International Health Division, Department of Health and Social Security, Alexander Fleming House, Elephant and Castle, London SEI 6BY, England.
INTERNATIONAL SURVEILLANCE: MEASURES TAKEN IN THE UK AT THE TIME OF THE EBOLA DISEASE OUTBREAK IN SUDAN AND ZAIRE 1976
The control of outbreak of any specific disease should be based on an agreed national policy. This must be based on:
a. the epidemiology of that disease;
b. the organization of government services in that country.
In the UK the control of notifiable infections disease is mainly the responsibility of local government. The doctor responsible is the medical officer for environmental health for each district.
Certain diseases are made notifiable by statutory provisions of the public health acts and regulations by central government to facilitate the monitoring and surveillance. In 1976 the headings, Lassa Fever, Rabies, Marburg Disease and Viral Haemorrhagic Fevers were added to the list.
In the context of the control of infectious disease the DHSS publishes from time to time memoranda incorporating advice for the guidance of the professions on methods of control of such diseases, eg. memoranda have been produced on the control of smallpox, Lassa fever etc.
When the outbreak of Ebola disease in the Sudan and Zaire came to our attention in the UK in mid-September 1976, very little was known about the epidemiology of the disease and in the circumstances it was decided to apply with some minor modifications the same methods of control that had been drawn up for Lassa fever. Fortunately, the memorandum on Lassa fever, giving guidelines on dealing with a case or suspect case of Lassa fever had just been published and circulated to all registered doctors in the UK who were asked to refer to it if needed.
The control measures rested on:
a. early identification of known or suspected cases based on the probability that patients were not infected before onset of symptoms;
b. their isolation, using only the special facilities designated for the purpose and special transport and designated laboratory facilities;
c. surveillance of contacts ensuring cases were identified before there was secondary spread. The limits of the designated infected region were based on WHO reports in October of an outbreak of a viral haemorrhagic fever resembling Marburg disease; initially South Sudan and North Zaire, later South Sudan and the whole of Zaire.
The Microbiological Research Establishment (MRE) Porton was one of the three laboratories which played an important role in international surveillance providing facilities for examination of specimens from world wide sources.
From mid-October all persons coming from the infected area to the UK via ports or air ports were placed under surveillance. There was no restriction on movements of persons regarded as contacts. Port health units were advised by the Department of Health and Social Security 5DHSS) about isolation in a designated hospital for anyone with pyrexia, in consultation with the Medical Officer for Environmental Health (MOEH) and an expert in infectious diseases.
For those without temperature 21 days surveillance was instituted. Any person changing district was notified to the new district and change of country notified to the Embassy of that country, or to the Scottish Office, Welsh Office, Northern Ireland or Eire.
This exercise mainly involved aeroplanes. If a plane arrived at a UK port from an infected area all passengers' names and destination addresses were taken by the Port Health Authority and passed to Central Government (DHSS Communicable Disease Division) who in turn passed each to the appropriate district containing the destination address. The local MOEH was responsible for clinical checking for 21 days. Transit passengers had name, destination, address and, if known, flight number passed to Central Government (DHSS International Health Division) and thence to the health authorities of the country to which they were travelling.
Where indirect flights were involved, eg. from the affected area via a European City, passengers were asked by means of prominent notices in the airport to inform immigration on arrival of their recent stay or travel through infected areas. These people were then referred to the Port Health Unit.
In addition a Press notice was issued by DHSS at the beginning of the outbreak informing the public of the situation and the measures being taken. A central operations room was set up at DHSS for inquiries.
There were loopholes in the system. Certainly a number of passengers failed to notify the immigration officers of recent visits to affected areas and did not reach port health, some coming via other European Capitals also passed through unnotified.
There were inaccuracies in addresses given, eg the Grosvenor Hotel, London was insufficient to distinguish between 3 or 4 hotels. Others did not have a destination address or could not give an exact account of movements within the next day or two. Use of existing medical surveillance machinery was useful but meant that other tasks had to be abandoned. Some areas, especially London areas receiving most of the visitors, were stretched to the limit of their manpower. Had the inflow of traffic from the infected areas been any heavier or had the outbreak lasted longer, there would have been difficulties in maintaining the surveillance scheme.
There was, however, much unofficial co-operation from persons returning from the area and from medical officers of firms with personnel working in the area.
MOsEH and Port Medical Officers were kept informed of the situation in a series of letters sent from the Chief Medical Officer of the Department of Health on such matters as:
i. symptoms of the original Marburg disease;
ii. the present status of the outbreaks;
iii. limit of infected areas;
iv. port and airport control measures etc.
In all some 400 passengers passing through ports of entry into the UK were placed under surveillance for periods of up to 3 weeks, between mid-October and mid-December. None of these were considered as suspect cases although two were feverish. There were no severe clinical conditions discovered in the course of the exercise and no admissions to designated units for isolation.
In general, there was considerable co-operation from the public, local authorities and also those firms employing people in affected areas.
In the event of any future similar infectious outbreaks similar policy would be adopted with modification of reporting and surveillance measures and possibly distribution of manpower, exact policy depending on the nature of the disease involved and what was known about its epidemiology. It is hoped that familiarity with a disease or development of a vaccine would probably allow less stringent vigilance.
TRANSPORT: TRANSIT ISOLATOR FOR AREA MEDICAL EVACUATION OF PATIENTS
Recently several highly infectious diseases have come to the fore which were previously unknown: Lassa fever, Ebola disease, etc. Situations may arise where UK nationals suffering from a highly infectious disease may require transport from abroad to the UK.
Epidemiologically, it is undesirable to move patients from an infected to a non-infected area as this creates the potential risk of introducing and spreading a non-indigenous disease into a new country. It is therefore of prime importance that efforts be made for local facilities to be adequate for treatment of such patients: buildings, equipment and manpower and possibly the setting up of plasma banks in endemic areas for treatment on the spot.
Humanitarian or other considerations may give cause for transfer of a patient from an endemic to a non-endemic area. The problem is then how to do this in the safest way. To this end a transit isolator for use in aeromedical evacuation has been developed in the UK along the lines of the static isolator which has already been produced for use in hospitals.
The UK has proceeded with formation of an aeromedical evacuation team for transport of British subjects with highly infectious diseases, if necessary. The Royal Air Force has agreed to establish and maintain such a team. Having had an aeromedical unit for many years they have the experience and requisite expertise and capabilities to transport ill persons by air.
The team, drawn from this unit, has received training at Coppetts Wood Hospital in London and is continuing with inflight training using a transit isolator developed at the Microbiological Research Establishment, Porton Down.
The present plan is, should a case arise, it would be referred to one or more UK medical experts, if possible in contact with the medical consultant looking after the patient and in conjunction with the RAF doctor involved, and they would decide whether evacuation was medically advisable. An advance party may be necessary to look at the feasibility of evacuation and set up transport and communication links. Many other problems such as type of protective clothing to be used, hospital facilities to be used in the UK, procedure for dealing with patients' relations, permission for over flying countries en route to the patients etc. are being worked out.