1990. a Cumulative Review of Studies on Travellers, Their Experience of Illness and the Implications of These Findings PDF

8/10/2019 1990. a Cumulative Review of Studies on Travellers, Their Experience of Illness and the Implications of These Find

1/16

Journal of nfection

I99O), 21, 27-42,

A c u m u l a t i v e r e v i e w o f s t u d i e s o n t r a v e l l e r s , t h e i r e x p e r i e n c e

o f i l l n e s s a n d t h e i m p l i c a t i o n s o f t h e s e f i n d i n g s

J. H . Co s s a r ,* D . R e i d ,* R . J. Fa l l o n , t E . J. Be l l , ~ M. H. Ri d i n g ,~

E . A . C. F o l l e t t , 1 B . C . D o w , ~ S . M i t c h e l l * * a n d N . R . G r i s t t t

*Communicable Diseases (Scotland) Unit, t Department of Laboratory

Medicine, ~Regional Virus Laboratory, ~ Scottish Se rum Ban k, IIHepatitis

Reference (Scotland) Laboratory, Ruchill Hospital, Glasgow G2o 9NB,

~lGlasgow and West of Scotland Blood Transfusion Service, Law Hospital,

Carluke, Lanarkshire ML8 5ES, **Scottish Health Education Group,

Woodburn House, Canaan Lane, Edinburgh EH Io 4S G and aftUniversity of

Glasgow Department of Infectious Diseases, Glasgow GI2 8QQ

Scotland, U.K.

Accepted for publication 19 February I99O

S u m m a r y

A cumulative review of illness experienced by 13 816 travellers returning to Scotland

since I977, shows an overall attack rate of 36 . Alimentary complaints predominated;

I8 of travellers had these alone and a fur ther IO had other symptoms as well as

their gastro-intestinal disorder.

Higher attack rates were noted in those taking package holidays. Inexperience of

travel, smoking, more southerly travel and younger age (particularly those between

2o- and 29-years-old) were other contributing factors. A similar pattern emerged from

a I year study of hospital in-patients with travel related admissions.

Serological studies of 47o travellers showed that 20 had incomplete immuni ty to

poliomyeli tis; 25 of those tested (3 I2 travellers) had serological evidence of typhoid

immunisation, 1.9 (of 76o travellers) had antibodies to

Legionella pneumophila, 64

(51I travellers tested) had antibodies to hepatitis A, 87 (288 tested) had adequate

levels of tetanus antitoxin but only 4o of the 225 travellers tested had adequate levels

of diphtheria antitoxin.

Amongst a subgroup of 645 travellers the travel agent was the most frequently

consulted source of pre-travel health advice. This carries particular significance for the

dissemination of relevant advice in view of the inadequacies found from study of the

health information in travel brochures.

These findings, viewed against the perspective of the continuing growth in

international travel, means that travellers, the medical profession, the travel trade,

health educators, global health agencies and health authorities in those countries

accepting and encouraging tourists, will be required to recognise the health

implications of further tourism development if this problem of illness associated with

travel is to be brought under control.

Introduct ion

The last few decades have witnessed a remarkable growth in international

travel. Thi s has followed increased trade, political cultural and sports

exchanges between nations, mili tary manoeuvres, pilgrimages, labour and

o163-4453/9o/o4oo27 + I6 So2.oo/o I99O The British Society for the Study of Infection


2/16

28

] H C O S S A R ET 4L

r e f u g e e m o v e m e n t s , a n d m o r e f r e q u e n t t o u r i s t t r a v e l - - 3 4 I m i l l i o n i n I 9 86

a l o n e . 1 G r o w t h h as a ls o b een p r o m o t ed b y a s o p h i s t i c a t ed t r ave l t r ad e

c o m b i n e d w i t h th e s p e e d ( c r u is i n g sp e e d o f C o n c o r d e I 3 5 6 m . p . h . ) , c o m f o r t

a n d c a p a c it y ( 4 0 0 + p a s s e n g e r s p e r j u m b o j e t ) o f t h e m o d e r n p a s s e n g e r

a e r o p la n e . A l l th e s e p o p u l a t i o n m o v e m e n t s h a v e t h e p o t e n t i a l f o r tr a n s m i s s i o n

o f in f e c t i o n a n d t h i s i s i n c r e a se d b y o v e r c r o w d i n g , i n a d e q u a t e s a n i ta t i o n

f ac il it ie s , an d w h en t h e c l i ma t i c an d cu l t u r a l co n t r a s t s b e t we en h o m e an d g u e s t

c o u n t r i e s ar e m o s t e x t r e m e , s u c h as f o r e x a m p l e b e t w e e n n o r t h e r n E u r o p e a n d

t rop ica l Af r i ca .

A s w e ll a s t h e f a m i li a r p r o b l e m o f t r av e l le r s d i a r r h o e a t h e f o ll o w i n g m o r e

s e ri o u s in f e c t io n s h a v e b e e n i m p o r t e d i n t o th e U . K . d u r i n g t h e l as t I o y e a r s :

ty ph oi d f ever 2 hep a t i t i s , ~-5 po l io my el i t i s , 6-8 lepto spir os is , 9 schis toso mia s is , 1 n

am oeb iasis,12 cholera,13.14 rab ies ~5 giar diasi s,l~ salmonellosis,XT. 18 shigellosis,19

dysentery,17 le ishmanias is ,20.21 lassa fever , 22 2~ t rypan osom ias is ,24 leg ion na ires

disease, 25-~7 diph th er ia , 28 29 cy tom eg alo vir us infe ct io n, s ma lar ia , 31 a cq uir ed

i m m u n e d e f i c ien cy s y n d r o me , 32 an d s ex u a ll y t r an s m i t t ed d i sea s es . 33 34

R eco g n i s i n g t h a t t h e s e p r o b l ems a r e s t ead i l y i n c r ea s i n g f o r t h e r ea s o n s

o u t l i n e d ab o ve , th e C o m m u n i c a b l e D i se a se s ( S c o tl a nd ) U n i t ( C D S U ) i n

a s so c i a ti o n w i t h t h e U n i v e r s i t y o f G l a s g o w D e p a r t m e n t o f I n f e c t io u s D i s ea s e s,

t h e D e p a r t m e n t o f L a b o r a t o r y M e d i c i n e , t h e R e g io n a l V i r us L a b o r a t o r y a n d

t h e S c o t t i s h H e a l t h E d u c a t i o n G r o u p ( S H E G ) , h a v e , s in c e I 9 7 7, b e e n a c t iv e l y

i n v o l v e d in m o n i t o r i n g t h e h e a l t h e x p e r i e n c e s o f r e t u r n i n g S c o t t i sh

t rave l lers 35-45 an d the i r im m u n i t y to infec t ion. 26 40.46-4s A t th e sam e t im e the y

h av e l o o k ed a t t h e ad eq u acy 49 an d way s o f i mp r o v i n g 5-52 cu rr en t pre - t ra ve l

h e a l t h a d v i ce . T h i s p a p e r p r e s e n t s p r e v i o u s l y u n p u b l i s h e d s t u d ie s , a n o v e ra l l

cu mu l a t i v e r ev i ew , an d s u g g es t s a c t i o n b a s ed o n t h e s e f i n d i n g s .

e t h o d s

B e t w e e n 1 9 7 7 a n d I 9 8 5 t r a v e l l e r s r e t u r n i n g t o S c o t l a n d a n d o n e g r o u p o f

v i s i t o r s t o S co t l an d h av e b een i s s u ed wi t h a s t an d a r d q u es t i o n n a i r e t o r eco r d

p e r s o n a l an d t r av e l d e t a i l s wh i ch i n c l u d e ag e , g en d e r , o ccu p a t i o n , co u n t r y ,

t o w n a n d t y p e o f a c c o m m o d a t i o n , d a t e s o f tr a ve l , r e a so n s f o r t r av e l, p r e - t r a v e l

h e a l t h s t a tu s , s y m p t o m a t i c c o m p l a i n t s w i t h d a t e o f o n s e t a n d d u r a t i o n , a n y

f a c to r s to w h i c h i l ln e ss m i g h t b e a t t r i b u t e d , a n d w h e t h e r t h e h e l p o f a d o c t o r

o r h o s p i t a l w a s r e q u i r e d . T h e q u e s t i o n n a i r e s w e r e r e t u r n e d t o C D S U u s i n g a

p r ep a i d r ep l y en v e l o p e . M o s t t r av e l l e r s we r e i s s u ed wi t h t h e q u es t i o n n a i r e a t

t h e i r r e t u r n a i r p o r t ( G l a s g o w o r E d i n b u r g h ) , s o m e b y tr a v el a g e n ts , e m p l o y e r s ,

a n d t o u r i s m d e p a r t m e n t s , a n d t h e r e m a i n d e r b y C D S U i n r e s p on s e to p u b li c

d e m a n d f o l l o w i n g m e d i a p u b l i c i t y w h i c h h a d h i g h l i g h t e d s p ec if ic e p is o d e s o f

t r av e l r e l a t ed i l l n e s s . T h e q u es t i o n n a i r e was u p d a t ed t o i n c l u d e d e t a i l s o n

s m o k i n g h a b i ts ( I 9 8 o ), t o m a k e c o m p l e t i o n a n d c o m p u t e r a n a ly s is e a s ie r

I98I), an d t o en q u i r e ab o u t p r e - t r av e l h ea l t h ad v i ce ( I 9 8 5 ) , b u t t h e b a s i c

i n f o r m a t i o n c o l le c te d r e m a i n e d o t h e r w i se e ss en ti al ly u n c h a n g e d t h r o u g h o u t

t h e p e r i o d o f s t u d y . T h i s en ab l ed v a l i d co m p ar a t i v e an a ly s e s to b e ca r r i ed o u t.

I n i t i a l l y t h e d a t a c o l l e c t e d w e r e a n a l y s e d m a n u a l l y , t h e r e a f t e r c o m p u t e r s

w e r e u s e d ( i n i t i a l l y a t C D S U , a n d l a t t e r l y G l a s g o w U n i v e r s i t y m a i n f r a m e ) ,

an d t h e i n f o r ma t i o n an a l y s ed u s i n g t h e S t a t i s t i c a l P ack ag es f o r t h e S o c i a l


3/16

Studies of travel related illness

29

S c i e n c e s ( S P S S x ) . T h e m a i n p r o b l e m w a s t h e s e l f -s e l e c ti o n b i a s o f t h e s a m p l e .

H o w e v e r , i f t h e r e a s o n a b l e a s s u m p t i o n is m a d e t h a t a ll t h e g r o u p s s t u d i e d h a v e

t h e s a m e r e s p o n s e b i a s a n d a n i d e n t i c a l m e t h o d o l o g y i s u s e d t h r o u g h o u t ,

c o m p a r i s o n w i t h i n t h e s e g r o u p s c a n b e j u st if i ed . W h e r e a p p r o p r i a t e t h e C h i -

s q u a r e d (X 2) t e s t i s u s e d i n a t w o - w a y t a b l e ; o c c a s i o n a l l y w i t h t e s t s f o r t r e n d

o r t h r e e - w a y t a b l e s i t w a s n e c e s s a r y t o u s e l o g - l i n e a r a n d l o g i s t i c m o d e l s .

M o re th an 75o of th e t rav e l le rs f r om sev era l of th e s tu die s 26' 35' 38-41' 4~

v o l u n t e e r e d a 5 m l s a m p l e o f v e n o u s b l o o d i n r e s p o n s e t o o u r r e q u e s t. T h e s e

w e r e c o l l e c t e d at R u c h i l l H o s p i t a l , a t tr a v e l le r s ' h o m e s a n d p l a c e s o f w o r k , a n d

w i t h t h e h e l p o f t h e i r f a m i l y d o c t o r s , p a r t i c u l a r ly f o r t h o s e d i s t a n t f r o m

G l a s g o w . T h e s e r u m s a m p l e s t h u s c o l l e c t e d w e r e d i v i d e d i n to p o r t i o n s a t

R u c h i l l H o s p i t a l l a b o r a t o r i e s f o r v a r i o u s a n t i b o d y t i tr e s to b e m e a s u r e d

v i z ,

p o l i o m y e l i t i s ( R e g i o n a l V i r u s L a b o r a t o r y ) , h e p a t i t i s A ( H e p a t i t i s R e f e r e n c e

L a b o r a t o r y ) ,

Legionella pneumophila

a n d

Salmonella typhi

( D e p a r t m e n t o f

L a b o r a t o r y M e d i c in e ) . T e t a n u s a n t it o x in l ev e ls w e r e m e a s u r e d a t t h e S c o t t is h

S e r u m B a n k ( R u c h i l l H o s p i t a l ) , a n d d i p h t h e r i a a n t i t o x i n l e ve ls a t t h e G l a s g o w

a n d W e s t o f S c o tl a n d B l o o d T r a n s f u s i o n S e r v ic e ( L a w H o s p i ta l ).

N e u t r a l i s i n g a n t i b o d i e s t o e ac h o f t h e t h r e e t y p e s o f p o l i o v i r u s w e r e

e s t i m a t e d u s i n g t h e m o d i f i e d m i c r o - m e t a b o l i c i n h i b i t io n t e st . 53 A l l s e r u m

t i t r a t i ons fo r t he l a t t e r w e re s t a r t e d a t a d i l u t i on o f I i n 4 ( i . e . I i n 8 i n f i na l

s e r u m v i r u s m i x t u r e s) w h i c h w e r e i n c u b a t e d f o r 3 h a t r o o m t e m p e r a t u r e

f o l l o w e d b y o v e r n i g h t i n c u b a t i o n a t 4 C. A l l t e s ts w e r e c a r r i ed o u t i n p a r al le l

w i t h B r i t i s h S t a n d a r d p o l i o v i r u s a n t i s e ra t y p e s I , 2 a n d 3 .

T o t a l a n t i b o d y t o h e p a t i ti s A v i r u s w a s m e a s u r e d b y a c o m p e t i t i v e

r a d i o i m m u n o a s s a y ( H A V A B , A b b o t t L a b o r a t o r i e s , C h ic ag o ), 47 s a m p le s w e r e

t e s t e d f o r a n t i b o d y t o L. pneumophi la a s d e s c r i b e d b y F a l l o n a n d A b r a h a m , 5 4

to

S. typhi

u s i n g a s t a n d a r d a g g l u t i n a t i o n t e c h n i q u e 55 e x c e p t t h a t t h e

i n c u b a t i o n t e m p e r a t u r e u s e d w a s 5 o C.

S e r a ( p r e v i o u s l y s t o r e d a t - 2 o C ) w e r e te s t e d f o r t e t a n u s I g G ( L a b s y s t e m s

U . K . , L t d ) a c c o rd i n g to t h e m a n u f a c t u r e r s r e c o m m e n d e d m e t h o d . T h e

c o n t r o l s w e r e t h r e e s e r a n e g a t i v e f o r t e ta n u s a n t i t o x i n a n d s e v e n p o s it i v e s e ra

w i t h k n o w n a n t i t o xi n c o n c e n t r a t io n s o f

o oo5-5

I U / m l . O p t i c a l d e n s i t i e s ( O D )

w e r e o b s e r v e d at 4 o 5 n m o n a F l o w M u l t i s c a n E L I S A r e ad e r. T o d e t e r m i n e

t h e i m m u n e s t a tu s o f a n i n d i v i d u a l a o . o I I U / m l p o s i t i v e c o n t r o l w a s u s e d a s

t h e c u t - o f f p o i n t . A n i n d i v i d u a l w i t h a t e s t OD > t h e o ' o I I U / m l p o s i t iv e

c o n t r o l w a s c o n s i d e r e d t o b e i m m u n e b u t s u s c e p t i b l e i f t h e t es t ra t io w a s l es s

t h a n t h i s v a l u e .

D i p h t h e r i a t o x o i d s e n s i t i s ed c e ll s w e r e p r o d u c e d i n a s i m i la r m a n n e r t o t h a t

d e s c r i b e d f o r t e t a n u s t o x o i d s e n s i t i s e d c e l l s b y B a r r

et al . 5~

H u m a n p l a s m a

a s s a y e d as 2 I U / m l b y t h e N a t i o n a l I n s t i t u t e f o r B i o l o gi c al S t a n d a r d s a n d

C o n t r o l w a s u s e d a s a r e f e r e n c e s t a n d a r d a n d a I i n 2 o o d i lu t i o n ( o ' o I I U / m l )

o f t h i s m a t e r i a l w a s u s e d i n a ll t e s t r u n s . I n t h e p a s s i v e h a e m a g g l u t i n a t i o n s l id e

t e s t, 5 o 1 o f t e s t s e r u m w a s m i x e d w i t h a n e q u a l v o l u m e o f 2 ~o d i p h t h e r i a

t o x o i d s e n s i t i s e d c el l s u s p e n s i o n o n a g l a ss s l id e . A f t e r 5 m i n a t r o o m

t e m p e r a t u r e , t e st s w e r e r ea d b y c o m p a r i n g w i t h t h e o -o I I U / m l c o n tr o l.

H a e m a g g l u t i n a t i o n s t r o n g e r t h a n th i s c o n t r o l in d i c a t e d t h e p r e s e n c e o f

d i p h t h e r i a a n t i t o x i n a t a n i m m u n e l ev e l ( i.e . > o . o i I U / m l ) .

D u r i n g t h e p e r i o d I J a n u a r y t o 3 I D e c e m b e r I 9 8 5 th e in - p a t ie n t d e ta il s


4/16

3 J . H . C O S S A R E T A L

( a )

We

Respiratory and other I

Respiratory I

Al imentary and respiratory 2

( b )

rotary 18

Al imentary and other 8

(N=I3 816)

Gostro enteritis

5 8

Malaria 3 8 9

ther 14

.. . . ~, . . . . . x infection 10

(/V=71)

Fig. I. Ty pes of travel illness. a), Illness reported by travellers from questionn aire studies

from z977-z985). b), Diagnoses recorded in in-patients from Ruchill Hospital ID Wards

I January I985 to 3~ December I985),

recorded on the Infec t ious D i seases ID) Un i t Record Shee t for admiss ions to

Ruchi l l Hospi ta l were used to compi le a prof i le on those with a travel

associated i l lness . These deta i l s inc luded age , gender , e thnic or ig in, diagnosis ,

length of s tay in hospi ta l , wh ether the i l lness was con sidered to be associated

with travel, the country v is i ted and the numb er o f days s ince returning to the

U . K .

Th e information co l lected by these meth ods was used to def ine a perspect ive

of travellers from the west of Sco t land and o f travel re lated il lnesses . D u e to

the retrospect ive nature o f the data co l lect ions , quest ionnaire rev is ion and

incomplete responses , the numbers analysed under di fferent categories of

study, o f necess i ty , have di f fer ing tota ls.

Resul t s

Thir teen thousand, e ight hundred and s ix teen comple ted ques t ionna ires w ere

returned. The response rate ranged from

2o 77 ~o

amongst indiv idual groups


5/16

Studies of travel related illness 3

3 5 0 0 ~

3 0 0 0 ~

r o 2 5 0 0 ~ -

2 0 0 0 ~

i s o o [

ooo[ i

E

g;

(a)

,e ..~

z

T

z

iiiiiiii i i i

i i i i i i i ; ;~ ;

iiiiiii i

:::::: ::

iiiii ii

iiiiiiii

o

(b)

i i i i i i i i i i i i

i

l

~ 9 ~ =

N m O

A g e g r o u p s A g e g r o u p s

F i g . 2 . D i s t r i b u t i o n o f t r a v e l l e r s b y a g e g r o u p a n d i l l n e s s . (a ) A g e o f t r a v e l l e r s a n d h e a l t h

e x p e r i e n c e ( f r o m q u e s t i o n n a i r e s t u d ie s ) . (I N ), T o t a l ; ( [ ] ) , n u m b e r u n w e l l . ( b ) T r a v e l

a s s o c i a te d a d m i s s i o n s ( f r o m R u c h i l l H o s p i t a l ) .

with a mean of 32 %. Thi rty -si x per cent rep orted illness (low I9 % in visitors

to Scotland in i98o, 37 high 78 - L. pneumophila study in z97726). As shown

in Fig. I, alimentary symptoms alone (diarrhoea or vomiting or both) were

reported most frequently by travellers (I8%), a further IO% had other

illnesses associated with alimentary symptoms . Gastro- intestina l illnesses and

malaria (both 38 %) were the two most comm on diagnoses recorded in the in-

patients stud ied du rin g I985 (total with travel rela ted illness - 7 I, i.e. 6 % of

all ID admissions).

Figure 2 shows the distribution of travellers by age group and illness, and

the age distribution of in-patients with travel related illness. In the former, the

fewest travellers were in the 0-9 and over 60 year age groups (4 and 9 %

respectively), the most in the 20-29 year group 22 ~ /o ) and the other groups

were closely ranged between z4 and I7 % (5 % did not give their age). Th e

20-29 year age group had the highest attack rate (48 %), there after attack rates

showed a progressive diminut ion with increasing age; those aged over 60 years

being least affected by illness (20 %). Illness was re por ted by 42 % of those

aged unde r 40 years (738I : 52 % of total travellers) and by 28 % above that age

(5764:42 %). Among st the 71 travel associated admissions, the most num ero us

were in the age group 20-29 years (25 %) closely followed by the 0-9 age group

(23 %). Al together those aged less than 4o years acc oun ted for 7I % of all these

admissions.

Th e gend er of the travellers was docu mente d in IO 9IO (79 %) of those who

returned questionnaires. There was no significant difference in the reports of

illness amongs t the 6064 females (56 % of total) and the 4864 males (44 % of

total) - 32 and 31% being unwell respectively.


6/16

32

J . H . C O S S A R ET AL.

Table I llness experienced by travellers according to place visited

S u m m e r W i n t e r

U n w e l l ( ) T o t a l U n w e l l ( ) T o t a l O v e r al l ( )

S c o t l a n d ( I 9 ) 355 - - - - ( 3 )

A u s t r i a - -

- - 2 0 )

44 (< x )

H u n g a r y ( 6 7) I 3 I - - - - ( I )

R o m a n i a ( 7 4) 3 8 0 - - - - ( 3)

Y u g o s l a v i a ( 2 7 ) 8 4 3 - - - - ( 6 )

B u l g a r i a ( 3 6 ) 2 2 6 - - - - ( 2 )

U . S . S . R . ( 3 7 ) I 6 8 ( I 2 ) 5 0 ( 2 )

I t a l y ( 2 1 ) 6 3 7 - - - - ( 5 )

G r e e c e ( 3 2 ) I 1 9 4 - - - - ( 9 )

S p a i n (36 ) 7035 (18 ) 147 (52 )

P o r t u g a l ( 4 4) 7 o i - - - - ( 5)

M a l t a ( 3 2 ) 5 8 1 ( 2 i ) 5 7 ( 5 )

C y p r u s ( 2 0) I 2 0 - - - - ( I )

T u n i s i a + M o r o c c o ( 7 7 ) 1 8 9 ( 3 2 ) 4 4 2 )

O t h e r ( 4 6 ) 9 1 4 - - - - ( 7 )

To t a l s 4962 (37 ) 13 474 67 (20 ) 342 13 816 ( IOO)

R a n g e s ( 1 9 - 7 7 ) (1 2 - 3 2 ) ( < 1-52

Th e smoking habits of travellers were dete rmined for IO 078 (73 ) of the

total number . Tw o thousand seven hun dre d and eighty-four (28 ) were

smokers of who m 37 reported illness; non-smok ers accounted for the

remaining 7294 travellers (72 ) with an overall attack rate of 32 . The

higher pe rcentage of smokers who were unwell compared with non-smoker s is

statistically significant (P < o.oooI).

Reports of illness according to season of travel and country visited are

displayed in Table I. The most visited countries were Spain (7182 travellers:

52 ) followed by Greece (II 94: 9 ) and Yugoslavia (843: 6 ); other

countries shared betwee n less than I and 6 of the total. Th er e is a tre nd

towards more attacks with travel further south and to some extent fur the r east,

and this remains generally true both in summer and winter. Examples in

suppor t of this tre nd are the 77 summe r attack rate repo rted by tourists to

Tunisia and Morocco, the 74 for Romania, and the rate of 32 reporte d

by winter tourists to Tunisia and Morocco. Attack rates in general are

substantially lower in winter (mean 20 ) than in sum mer (mean 37 ).

Th e relationship betwe en the c ountry visited and the percentage of travellers

unwell is statistically significant (P< o-oooI). In countries having both

summ er and winter travellers, the highe r percentage of summer travellers who

were unwell is statistically significant for all locations except Malta (P v . v . v . ' . v . v . ,

. . . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . . . .. . l 1 3 6 % : : : : :: : : : :: : : : :: : : : :: : : : :: : : : :: : : : :: : : : :: : :. . .

: :::1 :;: :::[ o x . ; :> x x , x , x o / c x . : . x . : . . . . . . . . . . . .

: . : . : . : . : . : . : 1 y o : : : : : : i : :~:~:~:~:~:2 . . o :~ :~:~:~:~: : i : : : : i : 6 % i ii ~ i ~ l . 1 i : ; :; : : ii i 6 % : ;i~ i i: :i :: i: :

Trave l ag en t Fam i ly oc to r O th e r M u l t i - so u rc e No adv ice t oken

(22 ) (I l ) (14 ) (4 ) (56 )

Fig . 3 . Pro- t rave l hea l th advice , source and hea l th exper ience . (Ul ) , Tota l 645; ( [ ] )~ 3I

unwe l l ( I99 ) .

t o 3 ( 6 6 o f 6 6 2 4 t o t a l) , a n d s e t o f f i n g o o d h e a l t h ( 97 o f 9 7 4 4 t o ta l ) . I n v i e w

o f t h e s e f in d i n g s c o m p a r i s o n s w i t h t h e m i n o r i t i e s o u t s i d e t h e se b r o a d

c a t e g o r ie s , w h i c h i n v o l v e w i d e l y d i s p a r a t e p r o p o r t i o n s o f t r a v e ll e r s, r e q u i r e t o

b e i n t e r p r e t e d w i t h c a u t io n . T h e p r o p o r t i o n ( z 1 ) w h o s t a y ed i n s e lf - c at e ri n g

a c c o m m o d a t i o n r e p o r t e d a lo w e r at ta c k ra te ( 2 6 ) t h a n t h o s e u s i n g o t h e r

t y p e s o f a c c o m m o d a t i o n , a s d i d t h e 4 s ta y i n g a b r o a d f o r m o r e t h a n 3 0 d a y s

(2 3 u n w e l l ) w h e n c o m p a r e d t o g r o u p s w i t h a d i ff e r e n t l e n g t h o f s ta y a b r o a d ;

s i m i l a r g r o u p c o m p a r i s o n s r e v e a l e d th e l o w e s t ra t es a m o n g s t t h o s e t r a v e ll i n g

f o r b u s i n e s s a n d h o l i d a y p u r p o s e s ( < z ) , IO u n w e l l , a n d i n t h e e m p l o y e r s

a n d m a n a g e r s , s o c i o - e c o n o m i c g r o u p (9 ) , 2 6 u n w e l l , c o m p a r e d w i t h o t h e r

s o c i o - e c o n o m i c g r o u p s . T h o s e w i t h a p r e - e x i s t i n g h e a l t h p r o b l e m ( 3 )

r e p o r t e d a h i g h e r i ll n e s s r a t e ( 4 6 ) .

A m o n g s t t h e 6 4 5 t ra v e ll e rs p r o v i d i n g i n f o r m a t i o n o n t h e u s e o f p r e - t r a v e l

h e a l t h a d v ic e ( F i g . 3 ), 2 8 4 ( 32 ) s o u g h t s u c h a d v i c e o f w h o m IO 5 ( 37 )

r e p o r t e d i ll ne ss c o m p a r e d to 9 4 ( 2 6 ) o f t h o s e w h o d i d n o t s e e k a d v ic e

( 56 ) . T h e t r av e l a g e n t w a s m o s t f r e q u e n t l y c o n s u l t e d f o r a d v i c e a n d t h e s e

z 33 tr a v e l l e r s ( 2 2 ) r e p o r t e d t h e l e a st i l l n e s s ; t h e f a m i l y d o c t o r w a s le a s t

c o n s u l t e d a n d a m o n g s t t h e s e 6 6 t r a v e ll e r s (z 1 ) t h e h i g h e s t a t ta c k r a te w a s

r e c o r d e d ( 4 2 ) . D u e t o o v e r l a p in t h e n u m b e r s o f t r a v e ll e r s s e e k i n g a d v i c e

f r o m t w o o r m o r e s o u r c e s , t h e p r o p o r t i o n s i n F i g . 3 a d d u p t o m o r e t h a n

I O 0

.

D e t a i ls o f t h e m e d i c a l m a n a g e m e n t o f t r a v el le r s w e r e c o l le c t ed f r o m 3 o 4 9

( 6 I ) o f t h o s e w h o w e r e u n w e l l . A l m o s t a q u a r t e r ( 2 4 ) w e r e c o n f i n e d t o

b e d , I 4 r e q u i r e d t h e s e r v ic e s o f a d o c t o r ( 9 a b r o a d , 5 a f te r r e t u r n i n g ) ,

a n d 61 (2 ) w e r e a d m i t t e d t o h o s p i t a l - - a l m o s t e q u a l l y d i v i d e d b e t w e e n h o m e

a n d a b r o a d .

A t o t a l o f I 2 6 5 a d m i s s i o n s to t h e i n f e c t i o u s d i se a s e s w a r d s w e r e r e c o r d e d

d u r i n g t h e I y e a r s tu d y p e r i o d a n d 7 I ( 6 ) , a s s h o w n in F ig . 4, w e r e

a s s o c i a te d w i t h t r a v e l a b r o a d (4 4 m a l e s : 6 2 ; 2 7 f e m a l e s : 3 8 ) . A m o n g s t

b o t h m a l e s a n d f e m a l e s th e m o s t r e p r e s e n t e d g r o u p w e r e A s i a n s (5 7 a n d 5 2

2 J I N 2 1


8/16

3 4 J . H . C O S S A R E T A L

Asian)

(m ale Caucasian)

17 ; 24

3 ; 4

(female African)

(male Afr ican) 2

4

ale Caucasian)

(female A sian) 14; 20

F i g . 4 . T ra ve l a s soc ia t e d admi s s i ons ( f rom R uc h i l l Hosp i t a l ) . (m ) , M a l e As i a n ; ( [~ ) ma l e

C a uc a s i a n ; ( [ ] ) , m a l e Af r i c a n ; ( [] )~ f e m a l e As i a n [ ] , f e ma l e C a uc a s i a n ; ( [ ] ) , f e ma l e Af r i c a n .

r e s p e c t iv e l y ) n e x t w e r e C a u c a s i a n s , a c c o u n t i n g f o r 3 8 o f t h e t o ta l o f t h e s e

a d m i s s i o n s . A f r i c a n s w e r e l e a st n u m e r o u s , (7 o f t h e t o ta l ).

S i x t y p e r c e n t o f t h o s e a d m i t t e d h a d v i s i te d th e I n d i a n s u b c o n t i n e n t ( 37

P a k i s t a n : 2 3 I n d ia ) . O f t h e r e m a i n d e r , v is i to r s t o S p a i n a c c o u n t e d f o r I 4 ,

t o N i g e r i a I 1 a n d I 6 h a d v i s i t e d o t h e r c o u n t r ie s . T h e m e d i a n in t e rv a l

b e t w e e n r e t u r n a n d a d m i s s i o n w a s I 4 d a y s (r a n g e 1 - 3 6 5 d a y s ) , t h e m e a n

l e n g t h o f s t a y i n h o s p i t a l w a s 6 d a y s ( r a n g e I - 4 I d a y s ) , a n d t h e t o t a l h o s p i t a l

' b e d - d a y s ' a c c o u n t e d f o r b y th e s e a d m i s s io n s w a s 4 3 2.

B e t w e e n I 9 7 7 a n d I 9 8 I , 7 6 I t r a v e l l e rs w e r e t e s t e d fo r a n t i b o d i e s t o L .

pneumophila

o f w h o m I 5 ( I '9 ) w e r e s e ro p o s it iv e . T h e s e h a d r e s p o n d e d to

m e d i a p u b l i c i t y h i g h l i g h t i n g l e g i o n e ll o s is a n d t r a v e l t o B e n i d o r m . 26

D u r i n g t h e p e r io d I 9 7 9 - I 9 8 2 , 4 7 o sa m p l e s w e r e t e s te d f o r p o l io m y e l i t i s

n e u t r a l i s i n g a n t i b o d y 4 ( T a b l e I I ). T h e a g e s r a n g e d f r o m I 5 - 8 3 y e a r s ; 5 5

w e r e a g e d 3 o - 6 0 y e a r s . E i g h t y p e r c e n t w e r e c o n s i d e r e d i m m u n e t o i n f e c t i o n

b u t s o m e in e a c h a g e g r o u p w e r e s u s c e p t i b l e to a t l ea s t o n e s e r o t y p e ; t w o h a d

n o a n t i b o d i e s . A n t i b o d i e s t o p o l i o v i rn s t y p e s i a n d 3 w e r e th o s e m o s t

f r e q u e n t l y a b s e n t ; 8 a n d I 1 o f t h e t ra v e l le r s h a d n o d e t e c t a b l e a n t i b o d y t o

t h e s e t y p e s , w h i l e 4 5 h a d n o a n t i b o d y t o p o l i o v i r u s t y p e 2 .

F r o m I 9 7 9 - I 9 8 2 , 7 9 ( 25 ) o f t h e 3 I Z s e ra t e s t e d f o r a n t i b o d i e s to almonella

typhi w e r e p o s i t i v e 4 a l t h o u g h t h e l e v e ls w e r e l o w e x c e p t i n 2 2 t r a v e l l e rs w i t h

' H ' a n t i b o d i e s a t a t i t re o f 1 60 o r g r e a te r . T h r e e s e ra h a d a n t i b o d y l ev e ls w h i c h

c o u l d b e d i a g n o s t ic a l ly c o n f u s i n g , t w o h a v i n g ' O ' t i t r es o f 3 2 o , a n d t h e o t h e r

a n ' O ' t i tr e o f 4 o a n d a n ' H ' t i tr e o f 6 4 o ; n o o t h e r s e r a h a d a n ' O ' t i tr e > I6 O .

F i v e h u n d r e d a n d e l e v e n s a m p l e s w e r e t e s t e d f o r a n t i b o d i e s t o h e p a ti t i s A ~7

( T a b l e I I I ) ; 6 4 w e r e a n t i - H A V p o s i t i v e w i t h a r a n g e o f f r o m 3 o ( ag e


9/16

Stud ies o f t rave l re la ted i l lness

T a b l e I I

A nt ib od y s ta tus o f t rave l lers to po l iov iruses ~ ,2 ,3

3 5

A g e g r o u p

( y e a r s )

W i t h o u t T o t a l

a n t i b o d y * ~ O n e T w o A l l t h r e e ~ n u m b e r

( ) / t y p e ( ) t y p e s ( ) t y p e s t ( ) J t e st e d

O v e r a l l

( )

I o - I 9 ( 4 ) (4 ) ( I 3 ) ( 7 8 ) 2 3 ( 5 )

2 0 - 2 9 ( 4 ) ( I 8 ) ( 7 8) I I 9 ( 2 5)

3 0 - 3 9 ( 3 ) ( I 7 ) ( 8 0 ) 6 6 ( I 4 )

4 0 - 4 9 ( 3 ) ( 8 ) ( 8 9 ) 9 I ( 1 9 )

5 0 - 5 9 ( i ) ( 7 ) ( 1 4 ) ( 7 8 ) i o o ( 2 i )

6 o + - - ( 6) ( i 7 ) ( 77 ) 7 I ( I 5 )

T o t a l s 2 ( < I ) 22 (5 ) 68 I 4 ) 3 7 8 ( 8 0 ) 4 7 0 I 0 0 )

R a n g e ( o - 4 ) ( 3 - 7 ) ( 8 - 1 8 ) ( 7 7 - 8 9 ) ( 5 - 2 5 )

* A t a t i t r e o f < 8 .

t A t a t i t r e o f > 8 .

T a b l e I I I

A n t i b o d y s t a tu s o f t ra v el le r s t o h e p a ti ti s A a n t i - H A V )

A g e g r o u p S e r o p o s it iv e T o t a l n u m b e r O v e r a ll

( y e a r s ) ( ) t e s t e d ( )

I O - I 9 ( 3 ) 2 3 ( 5 )

2 0 - 2 9 ( 3 8 ) I I 9 ( 2 3 )

3 0 - 3 9 ( 4 8) 6 6 ( I 3 )

4 0 - 4 9 ( 8 5 ) 9 1 ( I 8 )

5 0 - 5 9 ( 7 8 )

I o o

(20 )

6 0 + ( 8 9 ) 7 1 ( I 4 )

N o t k n o w n ( 6 3) 4 1 ( 8)

T o t a l s 3 2 8 ( 6 4 ) 5 1 1 ( IO O )

R a n g e ( 3 o- -8 9 ) ( 5 - 2 3 )

g r o u p i o -- I 9 y e a r s ) t o 89 ( a g e g r o u p o v e r 60 y e a r s ) . T h e r e w a s a r is e i n

s e r o p o s i t i v i t y w i t h i n c r e a s i n g a g e a p a r t f r o m a s li g h t d ip i n t h e 5 0 - 5 9 y e a r a g e

g r o u p . T h e p r e v a l e n c e o f a n t i - H A V in t h o s e a g e d u n d e r 4 o y e a r s c o m p a r e d

w i t h th o s e o v e r 4 0 y e a r s w a s 4 o a n d 8 3 r e s p e c t iv e l y . N o d i f f e r e n c e o f n o t e

w a s r e c o r d e d i n a v e r a g e s e r o p o s i t i v i t y b e t w e e n e a r l i e r ( I 9 7 9 ) a n d l a t er s a m p l e s

( x 9 8 3 ) .

E i g h t y - s e v e n p e r c e n t o f t h e 2 8 8 s e r u m s a m p l e s a n a l y s e d f o r p r e v a l e n c e o f

t e t a n u s a n t i to x i n h a d a d e q u a t e l e v e ls ; t h is e n c o m p a s s e s a r a n g e o f f r o m 7 4

( l ow e s t ) i n t h e 4 0 - 4 9 y e a r a g e g r o u p , t o Io o ( h ig h e s t ) i n t h e 3 o - 3 9 a n d 5 0 - 5 9

y e a r a g e g r o u p s .

T w o h u n d r e d a n d t w e n t y f iv e s a m p l e s w e r e t e s t e d f o r p r e v a l e n c e o f

d i p h t h e r i a a n t i t o x i n , 4 0 o f w h i c h h a d l ev e ls c o n s i d e r e d to b e p r o t e c t iv e .

T h e s e ra n g e d b e t w e e n 3 2 i n t h e 2 0 - z 9 y e a r a g e g r o u p a n d 55 i n t h e 4 0 - 4 9

y e a r a g e g r o u p .

2-2


10/16

36 j .H . COSSAR E T A L

i s c u s s i o n

T h e e p i d e m i o l o g i c a l p a t t e r n s w h i c h e m e r g e f r o m t h i s c o m p a r a t i v e a n a ly s is

r e p o r t e d b y t ra v e ll e rs w i t h i n d i f fe r e n t c o m p o n e n t s t u d y g r o u p s , w i t h r e g a r d t o

v a r i a t i o n s b y t y p e o f il ln e s s, ag e g r o u p , c o u n t r y v i s i ted , s ea s o n o f tr av e l ,

l i f e s t y l e f ac t o r s , h o s p i t a l i s a t i o n , p r e - t r av e l h ea l t h ad v i ce an d s e r o l o g i ca l

i m m u n i t y t o i n f ec t i o n s , h e l p t o d e f i n e t h e p e r s p ec t i v e o f t r av e l r e l a t ed i l ln e s se s

an d a s s o c i a t ed r i s k f ac t o r s . I t t h e r eb y b eco mes p o s s i b l e t o s u g g es t way s i n

w h i c h i m p r o v e m e n t s m a y b e m a d e i n p r o t e c t i n g a n d a d v i s i n g t h e t r a v e l l e r .

T h e 2 8 a t t a ck r a t e f r o m a l i men t a r y a i l men t s ( a l on e o r i n a s s o c i a t io n w i t h

o t h e r s y m p t o m s ) is t h e s am e as t h a t r e p o r t e d i n a s t u d y o f t r av e l l e r s' d i a r r h o e a

( 1 6 5 6 8 r an d o ml y s e l ec t ed S wi s s t r av e l l e r s ) , b y S t e f f en et al 57 T h e r a t e s

r ep o r t e d b y o t h e r r e s ea r ch e r s r an g e f r o m I 8 58 ( 26 6 5 F i n n i s h tr av e ll e rs ) to

4 I 59 ( 2 8 14 S co t t i s h h o l i d ay m ak e r s ) . T h a t t h i s i s t h e p r o b l em m o s t li k el y t o

a f f l i c t t h e t r av e l l e r i s a l s o co n f i r med b y C v e t an o v i c ' s e s t i ma t e t h a t i n

M e d i t e r r a n e a n c o u n t ri e s o f t h e E u r o p e a n r e g io n o f t h e W o r l d H e a l t h

O r g a n i z a t i o n t h e y e a rl y n u m b e r o f p e o p l e a f f ec t ed b y d i a r r h o e a i s I 2 m i l l io n

i n a p o p u l a t i o n o f 2 4 2 mi l l i o n , an d t h a t t o u r i s t s c o m i n g t o t h e s e a rea s f r o m t h e

r e st o f E u r o p e r u n a ri sk o f d e v e l o p i n g d i a r rh o e a 2 o t im e s g r e a t e r t h a n i n t h e ir

h o m e c o u n t r ie s . 8 T h i s e m p h a s i s e s t h e p o t e n t i a l f o r t h e t r a n s m i s s i o n o f o t h e r

g as t r o - i n t e s t i n a l i n f ec t i o n s , i n c l u d i n g t y p h o i d an d p a r a t y p h o i d f ev e r s , a s we l l

a s t h e s p r e a d o f h e p a t i t is A , i n t h e i n c r ea s i n g ly p o p u l a r a n d c r o w d e d h o l i d a y

a r ea s o f t h e M ed i t e r r a n ea n co ast s.

F u r t h e r co n f i r ma t i o n o f t h e s e t r en d s i n t r av e l r e l a t ed i ll n e ss e s is r ev ea l ed b y

an a l y si s o f l ab o r a t o r y i so l at e s o f p a t h o g e n s f r o m t r av e ll e r s co l l a t ed a t t h e

C D S U , w h i c h sh o w s t h a t b e t w e e n I 9 7 5 an d I 9 8 6 t h e r e h a s b een a f i v e - f o l d

i n c r ea s e i n t h e an n u a l t o t a l o f r ep o r t s ( I 3 5 a n d 7 o 4 r e sp ec t i v e l y ) an d a

p r o p o r t i o n a t e r i se f r o m 6 2 - 9 0 i n t h e r ep o r t s r e l a t i n g t o h o l i d ay m ak e r s 61' 62

( i m p r o v ed r e p o r t i n g m ay a l so co n t r i b u t e t o th i s i n cr ea se ) . I f t h e a r ea s v i s i ted

b y t h e s e t r av e l l e r s a r e co mp ar ed , t h e i s o l a t e s f r o m t h o s e v i s i t i n g s o u t h e r n

E u r o p e n o w c o m p r i s e 4 5 o f t h e t o ta l c o m p a r e d w i t h 2 6 i n I 9 7 5 T h e r e i s

l e s s p r o p o r t i o n a t e ch an g e f o r t h o s e v i s i t i n g o t h e r a r ea s . A cu mu l a t i v e r ev i ew

o f t h e p a t h o g en s i s o l a t ed s i n ce I 9 7 5 s h o ws t h a t i n f ec t i o n s a s s o c ia t ed w i t h

i n a d e q u a t e f o o d h a n d l i n g a n d p o o r w a t e r s u p p l y o r s a n i t a t i o n a c c o u n t f o r

8 7 o f t h e s e r ep o r t s ( to t a l n u m b e r 4 9 2 I ) .

T h e r e l ax e d a t t i tu d e s a n d r e d u c e d i n h i b i t i o n s w h i c h a r e n a t u r a l e l e m e n t s o f

v a c a t i o n a l e n j o y m e n t e x p o s e t h e t r a v e l l e r t o r i s k s w h i c h h e m i g h t o t h e r w i s e

a v o i d, a n d t h e y u n d o u b t e d l y c o n t r i b u t e t o t h e i ll ne s se s h e m a y a c q u i r e , w i t h

t h e m o r e a d v e n t u r o u s , t h e l e s s i m m u n e a n d t h e l e s s e x p e r i e n c e d l i k e l y t o

s u f fe r t h e h i g h es t a t t a ck ra t es . F u r t h e r co n f i r m a t i o n th a t s m o k i n g is a ma r k e r

o f t h o s e w i t h h i g h e r r i sk l i fe s ty l e s ( e it h e r b y v o l i t i o n o r d e f au l t ) is p r o v i d ed

b y t h e s mo k e r s ' s i g n if i c an tl y g r ea t e r i n c i d en ce o f t r av e l r e l a t ed i ll n e ss e s as

r eco r d ed i n t h i s s t u d y .

T h i s s t u d y a n d o t h e r s a l re a d y m e n t i o n e d 57'59 w h i c h s p e c if y t h e m o s t

a f f ec ted ag e g r o u p ag r ee t h a t i t i s b e t w een 2 o an d 2 9 y ear s o f age , a r g u ab l y

t h o s e l i k e ly to h av e t h e h i g h es t r i sk l if e s ty l e. T h i s is s u p p o r t e d b y o t h e r d a t a

a n a l y s e d a t t h e C D S U a n d p r e s e n t e d at a C o n f e r e n c e o n I n t e r n a t i o n a l T r a v e l

M e d i c i n e ( Z u r i c h , A p r i l I 9 8 8 ) , w h i c h s h o w e d t h a t w h i l s t t h e s e c o n d m o s t


11/16

tudies of travel related i l lness

37

frequently recorded cause of death in travellers (total study numbers 395

pers ons; I98o -I98 5) was 'accidents and i njuri es' (I8 ~/o), the 2o-z9 year age

group had the highest morta lity fro m this cause. ~4

Th er e is similar study ag reement when the area is specified in that travel to

north Africa57' 58 or eastern Europe 59 produces the highest attack rates. Th e

geographical impact of climatic contrast, and the environmental impact of

cultural contrast reflected in the higher attack rates recorded in travellers

returning from areas having the greatest contrasts to their home country,

suggest that the greater the physiological stresses and the mo re unfamiliar the

contact with environmental pathogens, the more illness is experienced

(however, the virulence and dose of pathogen(s) is clearly of importance). T his

hypothesis is also supported by the similar attack rate trend seen in winter

travellers, and also the lower winter attack rates in general when compared

with summer travellers, both overall and for individual countries.

The studies showed no significant correlation between travellers reporting

illness and their gender, reason for travel, type of accommodation used, socio-

economic status or their length of stay abroad, although the highest attack

rates were recorded in those who were unskilled or unemployed, and those

who set off with pre-exi sting ill health. Mor e controlled studies would be

required to corroborate any vulnerability to illness in travellers compromised

by either poor health or economic factors.

The pattern of illness in those admitted to hospital following return from

abroad mirrors that seen in the questionnaire studies,

v i z

the 20--29 year age

group was the most represented and the majority presented with alimentary

symptoms. Comparatively it is of interest to note that in a review of overseas

visitors admi tted to a Lond on hospital during I986, 45 had infective

illnesses (the largest single group), many of these infections were tropical, and

the 2I-4o year age group was the most represented, 63 which is not dissimilar

to the pattern seen in this study. Although no specific denominators are

available for the Ruchill Hospital admission data, whe n one considers that the

majority of U.K. residents are of Caucasian extraction and do not travel

beyond Europe, 64 there is a disproportionate repre sentat ion of those

contracting malaria, of travel to the Indian subcontinent, and of Asian

extraction amongst this group. Thi s carries clear implications in terms of the

current inadequacy in giving an 'at risk' group pre-travel health advice

appropriate both in language and culture.

The disappointing finding that more illness was reported by those taking

pre-travel health advice than by travellers who did not suggests that there is

considerable scope for improving the quality of that advice, although perhaps

those not seeking it were mor e experienced and knowledgeable about avoiding

illness whilst abroad. Also of note was that the family doctor was asked for

health advice least often, and the travel agent most often. This carries obvious

implications as to the most suitable place where the traveller may obtain

advice. Surprisingly, the minority who consulted their family doctor repor ted

the highest attack rate, but perhaps member s of this group were the least fit of

the travellers and therefore the most vulnerable to illness. Most travellers

make their arrangements via a travel agent and the health advice given by the

latter is therefore of crucial importance. Other studies have revealed


12/16

38

1. H . C O S S A R E T A L

inadequacies in both the quality and consistency of advice appearing in travel

brochures, 49 and, by way of example, have resulted in a general, pre -trave l

health advice booklet being designed, produced and test-marketed by the

CDSU in association with the Scottish Health Educ ation Group . 5 This

advice complements that contained in Depa rtm ent of Health leaflet TA I. All

the necessary specific pre-tra vel health advice can be provided by the i nfor med

general practitioner who has access to free, regularly updated, information

charts, 65 or, for more complex itineraries, to t he

C D S U

computer ised database

which is updat ed weekly. 6~ As the general prac titioner is pr imarily responsible

for the health care of the returning traveller who is ill and has access to the

relevant past medical history and vaccination record, he is the best placed to

give appropriate medical advice to the departing traveller.

The economic benefits of effective advice can be measured against the

estimated IO million hospitalisation costs from travel associated admissions

based on calculations of the numbe rs requi ring hospital care and their average

costs in I986. 45 This figure takes no account o f the considerable additional

costs accruing from primary care and specialist consultations, laboratory

investigations, drug prescriptions, loss of working days and loss of vacation

time due to such illness.

Specific medical advice depends upon the travellers' pre-existing health

status, imm uni ty to infection and exposure risk which is affected by life style.

Some diseases less common in one country are more prevalent in another,

which may lead to problems when travellers become complacent about

immunisation before travelling to countries where the disease is more

common. By way o f example, 28 773 cases of paralytic poliomyelitis were

repor ted to the W HO in 1986, 67 whilst poliomyelitis antibody studies reported

here show that one in five of this group of travellers was incompletely immune.

Similarly three in four of those tested had no evidence of successful

immunisation to

S typhi

despite the fact that at the time of testing (I982),

63 of visits carried out by U.K. residents were to countries where

immunisation was recommended.6s In this same context one in eight of

travellers tested were at risk from infection with tetanus and two in three from

infection with diphtheria. The antibody studies for hepatitis A suggest that

almost one in t hree are at risk and support the cost effectiveness of selective

screening in the U.K . before giving immunoglobul in to older travellers at risk

from hepatitis A. 48 All the serological findings require to be int erp ret ed with

caution as immunity will vary from area to area within the U.K. and from

count ry to country. Th ey do however, provide a basis for assessment of the

immu nity of travellers exposed to these pathogens, which might be used not

only for the protection of the traveller, but also of the native community

following his retu rn who may be at risk fro m virulent strains of these importe d

infections because of low levels of herd immunity.

In summary, growth of travel and the numbers affected by travel related

illnesses, some of a serious nature, mean that this subject will increasingly

demand attention from the medical profession, the travel trade, travellers and

health authorities in countries visited by tourists.

The traveller is most likely to have a short self-limiting episode of gastro-

intestinal upset. Vulnerability to travel associated illness is increased by


13/16

Studies of travel related illness

39

inexperien ce of travel, in those aged betw een 20 and 29 years, in smokers,

during travel in the summer, and greater climatic and cultural contrast

between the traveller s c ountry of origin and his holiday destination. Provision

of appropriate general advice for the traveller, whi ch is already available, is a

shared responsibili ty which is best directed, in the main, through travel

agencies. It can be shown to be cost effective. Specific medical advice is best

provided by the informed general practi t ioner who is responsible for the

prima ry care of the return ing traveller who is unwell .

Continued monitoring of i l lness in travellers and provision of information

about the problem and its prevention, using traditional channels of

communicat ion and modern technology to which medical and related

disciplines have ready access is fully justified.

Increased collaboration between medical workers, health educators and

those involved in the travel trade would be a positive and efficacious

contribution to reducing illness and discomfort in travellers, as well as the

expense that this brings to international health services.

It is clear that man y countries benefit economically from the develo pment

of tourism. In r eturn they have to accept a responsibili ty towards the

prevention of illnesses associated with it.

(We thank the many individuals and organisations who assisted in the questionnaire

studies. These include Mr B. J. Forteath and Mr J. MacPherson and colleagues of

Renfrew Distric t envi ronmental health department, Mr C. Sibbald and staff of

Edinburgh City environmental health department, Mr H. N. Battersby and staff of

the British Airport Author ity, Miss M. Sinclair and staff of the city of Glasgow Public

Relations Department, the leisure, recreation, and tourism departments of Argyll and

Bute, Cunninghame District and Strathclyde Region, the Scottish Tourist Board, the

Common Services Agency, various Glasgow companies and travel agents, the British

Broadcasting Corporation, the family doctors of the travellers studied and the

travellers themselves who volunteered information about their health and agreed to

give a blood sample to help further the research.

We also wish to record our thanks to the infectious diseases consultants at Ruchill

Hospital for permission to study the Infectious Diseases Unit Record Sheets of their

patients during I985; Mr A Millar (audio-visual technician CDSU) for assistance

with the figures and tables; Dr D. Fildes and staff (Department of Computing

Science, Glasgow University), and Mr I. Cockett (formerly of the Common Services

Agency) for the computer programming and analyses required in the studies, and Dr

C. Robertson (Depar tment of Mathematics, Strathclyde University) for statistical

assistance.

This work was supported in part by the Chief Scientist Organisation, Edinburgh.)

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Documents

1990. a Cumulative Review of Studies on Travellers, Their Experience of Illness and the Implications of These Findings PDF