UNITED NATIONS
N A T I O N S UNIES
WORLD H E A L T H O R G A N IZAT ION C O M M I T T J S £ ON I N T E R W A T I O M L QUARANTINE
ORGANISATION MONDIALE DE LA SANTÉ 21 September ORIGINAL: 1954
Second Session
ENGLISH
REVISION OF THE YELLOW-FEVER PROVISIONS OF THE INTERNATIONAL SANITARY REGUUTIONS
Proposal by the United States Government
This Government i s o f the o p i n i o n that a new approach should be
considered
f o r the prevention of the spread of y e l l o w fever through i n t e r n a t i o n a l t r a f f i c . S p e c i f i c suggestions f o l l o w . 1A r t i c l e 70. Discussion. I t i s pro^josed to suppress t h i s a r t i c l e . I t appears to be impossible to d e f i n e endemic areas i n the
Americas which are acceptable to a l l the Governments concerned i n view of the Seventh World Health Assembly's a c t i o n contrarj' to that recommended bj' the Ccaranittee on I n t e r n a t i o n a l Quarantine. The r e s u l t i s that the second paragraph of A r t i c l e 70 Intended.
does not serve the purpose f o r which i t was
The conception of y e l l o w - f e v e r endemic areas to be d e l i n e a t e d by an i n t e r n a t i o n a l a u t h o r i t y was introduced by the I n t e r n a t i o n a l Sanitary Conventions of 1944. I t was r e t a i n e d i n the I n t e r n a t i o n a l S a n i t a r y Regulations which are In The f i r s t d e l i n e a t i o n was
force i n a l l but two of the American R e p u b l i c s . c a r r i e d out i n 1945 and 194b by UNRRA.
S l i g h t m o d i f i c a t i o n s of the zones were
made i n 1950 and 1951 by the World Health O r g a n i z a t i o n which had taken over the a d m i n i s t r a t i o n of the Conventions from UNRRA i n accordance w i t h the p r o v i s i o n s of the 1946 p r o t o c o l s . Neither i n A f r i c a nor i n the Americas were the y e l l o w - f e v e r endemic zones ever defined according to the d e f i n i t i o n given i n the I n t e r n a t i o n a l S a n i t a r y Regulations. The d e l i n e a t i o n s i n the Americas were made under p r o t e s t from s e v e r a l
South American c o u n t r i e s concerned. S e i z e d w i t h the question, but being of the opinion t h a t a fundamental r e v i s i o n of the clauses of the ISR should not be made by the Seventh World H e a l t h Assembly, members of Committee on I n t e r n a t i o n a l Quarantine only.
- 2 the Committee on International Quarantine proposed, in its first session, a del.:1neation for the Americas which took into account the ISR definition of yellow-fever endentic zones, adding as a dditional safeguards type. cerned. r ec ommendat~ons
regarding vaccination of ~
departing travellers and prompt r eporting under Article J of yellow-fever cases of . They wer e rejected by ~he
These recommendations were formally accepted by all the American repub1i.cs conSev€nth World Health Assembly by a close v.o~e.
Because of the difficulties of a practical nature in the application of Arti.cl.e it is suggested that yellow fever be dealt ",ith in the same manner as are the other quarantinable diseases. In the case of plague, cholera and smallpox it is the duty of each goverrunent to report at once the presenc ~
~J
of cas es of the se diseases and to declare local areas It is the duty of WHO prQIIIP~
infected, according to the rules established in the ISR. · to transmit such reports. own protection in conformity with the rules of the ISR.
Other governments may then take measures necessar.,y for the.il This system has worked well, Under this system plague has ceased to
and no ' complaints have been received by WHO. greatly reduced. sams manner.
be internationally transmitted, and the cholera-infected part of the world has ~en It seems reasonable, therefore, to deal with yellow fever in the
2.
Definition of "foyer". Discussion.
It is proposed to suppress this definition.
The reference in thE:. second sentence of the present ISR text to "th
first case of human yellow fever transmitted by Aedes aegypti" has been construed to exclude jungle yellow fever from the meaning of the first sentence, which reads. III
foyer' means the occurrence of two cases of a quarantinable disease derived from an
imported case, or one case derived from a non-imported cas, e ". The argument advanced is that a case of jungle yellow fever is not derived from another case but from a mo~ey.
However, a case of bubonic plague is but the intention was
U8~
derived
from a rat and not from another human case;
certain~
not to
relieve anyone of the obligation to notify plague cases other than those transmitted from man to man, nor has any government ever construed the definition in this sense. Moreover, it is rarely possible to determine the source of a first case of a quarantin, able disease in a local area unless it is directly related to a known imported case. The present wording of the definition is therefore ambiguous and impractical.
- 3 As a matter of f a c t , the conoeption o f "foyer" i s used i n the Regulations only f o r determining an " i n f e c t e d l o c a l area" i n connexion viith plague, c h o l e r a , "urban" yellow fever and smallpox. The ISR provide f o r measures against louse-borne typhus and
relapsing f e v e r only when these diseases are i n an epidemic s t a t e .
I t would be
simpler t h e r e f o r e t o suppress the u n s a t i s f a c t o r y d e f i n i t i o n of "foyer" and s t a t e the requirements d i r e c t l y i n t h e d e f i n i t i o n o f " i n f e c t e d l o c a l area". The present d e f i n i t i o n o f "epidemic" i s based on the d e f i n i t i o n of " f o y e r " and would t h e r e f o r e have t o be changed a l s o . I t should be kept i n mind that t h i s The f o l l o w i n g
d e f i n i t i o n i s used only i n connexion w i t h typhus and r e l a p s i n g f e v e r . i s suggested;
"epidemic" means the extension o f a quarantinable disease by a m u l t i p l i c a t i o n o f cases i n a l o c a l area.
3.
D e f i n i t i o n o f "yellow-fever endemic zones".
I t i s proposed t o suppress t h i s •
definition. D i s c u s s i o n . ' With the suppression o f A r t i c l e 70, t h i s d e f i n i t i o n becomes unnecessary. Quarantine s e r v i c e s are concerned w i t h human cases of yellow f e v e r and
not w i t h the existence of the v i r u s among animals i n the jungle so long as i t does not give r i s e t o human cases. Nevertheless, i t w i l l be u s e f u l t o maintain the warning d e c l a r a t i o n provided under A r t i c l e 7 o f the ISR o f evidence other than by a hvunan case of the presence of the v i r u s of y e l l o w f e v e r . Such d e c l a r a t i o n s are u s e f u l , apart from quarantine, because
governments may wish t o recommend that persons be vaccinated against yellow f e v e r i f going i n t o an area where t h e v i r u s i s known t o be present, and may a l s o wish t o s t a r t mass v a c c i n a t i o n i n exposed areas. The knowledge o f an approaching y e l l o w - f e v e r
e p i z o o t i c may lead t o the i n s t i t u t i o n of more a c t i v e Aedes a e g y p t i c o n t r o l , but such measures should not be confused w i t h quarantine. On the contrary, they are taken i n
conformity w i t h R e s o l u t i o n 79 of the Fourth World Health Assembly vdiich urges governments t o take preventive measures i n t h e i r own c o u n t r i e s . I n many cases, however, the
presence of the v i r u s i s not suspected u n t i l a human case turns up.
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Experience of the past ten years has shown that differences exist in our knowledge of the epidemiology of yellow fever in Africa and in the Americas. differences may, however, be only apparent. of control have been taken. and understood. The actual More information regarding the presence
of yellow fever is available in the Americas than in Africa, and more active measures The movements of yellow fever over vast geographical areas in the Americas and its subsequent disappearance for long periods are well known In Africa, little is known of the geographical movements of yellow fever, and the indices obtained by the mouse protection tests give past history rather than present distribution. Many governments of the western hemisphere have expended large sums and great efforts to control yellow fever. be recognized. These governments consider that their efforts should ~,
Traffic within each hemisphere is vastly greater than traffic between
receptive parts of the two hemispheres, and i f the nearby and more exposed countries satisfied that the proposed arrangement is safe far them it can be assumed that it would be safe for countries farther away. The governments more immediately concerned with the possible transmission of posals. 4.
yel1~
fever from Africa may recommend some modifications of or additions to the above proPerhaps special provisions with respect to Africa would meet their needs. It is proposed to change this
Defini tion of "yellow-fever receptive area".
definition to read as followss "yellow-fever receptive area" means an area in which, according to the government of the territory concerned, the virus of yellow fever does not exist but where the presence of Aedes aegypti would permit its development if introduced. Discussion. The present definition is rather vague, and it would be better :to The government should
specify the circumstances in which the governments themselves would determine whether rsceptive areas exist within their respective territories. governments. inform WHO of its decision, and this decision should be transmitted by WHO to other Similarly, the discovery of vectors in new areas, or their suppression where formerly prevalent, may lead to declarations of changes in receptive areas wbicb should be notified promptly.
- 5 5. Definition of "infected local area". It is proposed to change the wording of (a)
in conformity with the proposals made in the foregoing, and to suppress (d) leaving (b) and (c) unchangeds "infected local area" means (a) a local area where there is a non-imported case of plague, yellow fever, or or
cholera, or smallpox; (b) (c)
a local area where there is an epidemic of typhus or relapsing fever; a local area where plague infection among rodents exists on land or on
craft which are part of the equipment of a port. Discussion. The reasons for suppressing the reference to yellow-fever endemic
Zones in (d) have been given in the foregoing. It is the generally accepted opinion that a local area should be declared ~ected
when there is one case of yellow fever transmitted b,y Aedes aegypti, and the The added emphasis on human yellow-fever cases not likely to have Governments
ISR so provide. caS 6 S
been transmitted b,y Aedes aegypti seems warranted because it is the occurrence of human which indicate that a danger to international traffic may exist. should be reminded that notification of a first case of yellow fever is not to be delayed until laboratory confirmation has been received. This appears clearly from Article 3 of the ISR, but the provision has frequently not been observed. Similarly, where a non-imported case of plague occurs there will usually already be an epizootic among the rodents. It would be purposeless to awa~t
a second human case
before declaring the local area infected. a first non-imported ~se
As a matter of fact, it has been universal
practice for a great many years to declare a local area infected upon the occurrence of of plague.
Unlike plague and yellow fever, cholera and smallpox are not dependent for transmission on vectors and animal hosts. Wherever a non-imported case occurs there must So long as there is only a have been a reservoir of infection, recognized or not. in the case of choler ~
Single case and the disease is not present in neighbouring areas it may be reasonable, or smallpox, to await laboratory confirmation before declaring a When case follows, the local area should, of course, be local area infected provided the necessary laboratory facilities are available. the case is confirmed, or if another declared infected.
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I t w i l l be noted that the above proposals a f f e c t p r o v i s i o n s r e g a r d i n g d i s e a s e s other than y e l l o w f e v e r which was the only one mentioned i n the r e s o l u t i o n o f t h e Seventh World Health Assembly. I t seems d e s i r a b l e t o take t h i s o p p o r t u n i t y t o make
changes i n the other p r o v i s i o n s w i t h a view t o b r i n g i n g the r u l e s o f the ISR more i n t o l i n e w i t h c u r r e n t quarantine p r a c t i c e . These p a r t i c u l a r changes do not i n v o l v e c o n -
s e q u e n t i a l changes elsewhere i n the ISR.
^'
A r t i c l e 6.1 1.
I t i s proposed to change paragraph ( l ) t o read: area
The h e a l t h a d m i n i s t r a t i o n o f a t e r r i t o r y i n which an i n f e c t e d l o c a l
i s s i t u a t e d s h a l l inform the Organization when that l o c a l area i s f r e e f r o m infection. Discussion. I t i s proposed to omit the second l i n e of the present t e x t w h i c h This
reads "other than a l o c a l area which i s p a r t o f a y e l l o w - f e v e r endemic zone". change i s necessary because o f the suppression of A r t i c l e 70.
I t i s the government
of the t & r r i t o r y i n question which announces i n f e c t i o n and c e s s a t i o n o f i n f e c t i o n according t o the r u l e s o f ISR. Another government can complain i f i t i s i n p o s s e s s i o n
of i n f o r m a t i o n which seems t o iKvalidate the c l a i m o f c e s s a t i o n o f i n f e c t i o n . .
7.
A r t i c l e 6.2
Changes are proposed i n 6.2(b) a f t e r which t h i s p a r t o f the A r t i c l e
w i l l read} 2. An i n f e c t e d l o c a l area may be considered f r e o from i n f e c t i o n when a l l t o prevent t h e r e c u r r e n c e '
measures o f prophylaxis have been taken and maintained
of t h e disease o r i t s spread to other areas, and when (a) (b) \inchangedj i n the case of y e l l o w fever»
i f the-Aedes a e g y p t i index i s below
one per cent., when three months have elapsèd a f t e r the occxirrence o f the l a s t human case; or i f the Aedes aegypti index i s not below one per
" cent., when a year has elapsed a f t e r the occxirrence of the l a s t hximan case; (c) unchanged. . •• • • ! o • .
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Discussion.
The conditions p e m i t t i n g a government to declare an i n f e c t e d l o c a l o f the l a s t human case i n
area f r e e from yellow f e v e r are based on the occurrence
accordance w i t h the p r i n c i p l e s developed i n the proposals s t a t e d i n the foregoing. For quarantine purposes no d i s t i n c t i o n i s made, t h e r e f o r e , between "urban" and "jungle" yellow f e v e r . absence of Aedes a e g y p t i . But a d i s t i n c t i o n must be made i n regard t o the presence o r I f the vector index i n c i t i e s and around other h a b i t a t i o n s
i s n i l , or at l e a s t below one per cent., the absence o f human cases f o r three months should i n d i c a t e the c e s s a t i o n of danger of f u r t h e r t r a n s m i s s i o n . Otherwise, the
danger must be considered present u n t i l a year has passed a f t e r the l a s t human case thus a l l o w i n g f o r the f u l l c y c l e of changing seasons. I t i s suggested t h a t governments accompany d e c l a r a t i o n s of the c e s s a t i o n of i n f e c t i o n w i t h the necessary d e t a i l e d documentary evidence i n regard to Aedes aegypti
i n d i c e s i n order t o leave no doubts o f the j u s t i f i c a t i o n i n the minds o f other h e a l t h administrations.
8.
Other p r o v i s i o n s regarding yellow f e v e r .
Should the foregoing proposals be
adopted "yellow-fever endemic zone" would have t o be changed t o "yeUow-fever i n f e c t e d l o c a l area" i n A r t i c l e 20. I t i s not b e l i e v e d that the other A r t i c l e s o f the ISR regarding yellow f e v e r need r e v i s i o n a t t h i s time.