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Human infectious diseases associated with animals
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PUBLIC HEALTH, July, 1951
HUMAN INFECTIOUS DISEASES ASSOCIATED WITH ANIMALS* By JAMES MACRAE, M.D., F.R.F.P.S., D.P.H.,
Resident Physician, Ham Green Hospital and Sanatorium, Bristol It is not my purpose to lecture you about a number of obscure diseases but rather to speak of the very real relation animals have in the spread of human infections. I would like to consider first, and very briefly, the general method by which such infections continue to worry us. A living pathogenic organism must exist, it must have a reservoir to which it can retreat and it must have means of moving to and from the reservoir and the human case. T h e means of movement may be physical, as in respiratory infections, or it may be by the agency of insects ; or the organism may rely on chance, waiting patiently as a spore, as does the tetanus bacillus. It may be a combination of these. T h e reservoir of infection is often human but it can be insect, fish, reptile, bird or animal. While the whole chain is important, the reservoir factor is vital to the survival of the organism and, if it can be eliminated, infections as we know them could not flourish. Unless we know the reservoir there can be no adequate understanding of any infectious disease. Control of the reservoir offers the best chance of complete mastery of the disease. When the reservoir of infection is human there are obvious difficulties in exercising proper control. Should any other living thing constitute a harbourage for organisms then the possibilities are brighter. For a long time it has been known that animals can acquire certain human diseases and use has been made of this fact in the field of experimental medicine. Alternatively, animals can pass some of their own peculiar infections to man. In other words, there are animal reservoirs of disease and we can create others. In recent years knowledge of this thesis has broadened steadily, especially in the field of virus diseases, and now more than ever must we think seriously of the animal world when we seek the reservoirs of human disease. I do not propose to deal with excessively rare diseases, nor will I include the vast number of tropical infections which have animal or insect reservoirs. I have compiled a list of human diseases associated with animals. T h a t list is attached and it is by no means exhaustive. T h e World Health Organisation has recently classified 80 such diseases and calls them Zoonoses. A glance at my list, Table I, shows the probable magnitude of the whole problem. I propose to speak only of such of these infections as I have seen myself. Since my experience is limited, these are by no means uncommon.
(1) Tuberculosls It may be considered that the bovine bacillus causes some 10% of human tuberculosis and that 50% of the child abdominal infections come from the same origin. It is probable that 25% or more of the United Kingdom's dairy cows are infected with tuberculosis. Bovine pulmonary infection is comparatively uncommon in humans but the degree of bovine infection varies considerably from one part of the country to another. Owing to inadequate data regarding types of bacilli, accurate figures are not always available, but the possibility of bovine tuberculosis should always be at the forefront of one's mind. Tuberculous meningitis is not commonly caused by the bovine bacillus. I myself have seen seven cases in a total series of 164 followed in Scotland in the years before the war. It should be remembered that cattle can be infected by the human strain of bacillus and this particular danger can
occur even in the best conditions; indeed it very nearly happened in our hospital dairy herd when a new cowman was engaged and only discovered on routine examination to be suffering from active tuberculosis. T h e remedy lies in either wholesale slaughter of the infected animals or segregation of calves into tubercle free herds and, even if these things were done, one would still need to take constant care to avoid infection of the cattle by human cases.
(2) Salmonella Infections These infections are a progressively increasing cause of human enteritis. T h e y have an exceptionally wide animal reservoir and over 300 strains of the organism have already been identified. Some of you will probably remember Sir William Savage's recent talk on this subject in this university when he delivered his Long Fox lecture. This is the only enteric disease with an animal reservoir occurring in this country. In recent years the increasing prevalence of Salmonella infection might be due to increased bulk storage and, therefore, bulk contamination by mice and rats or to the import of unusual items such as dried egg, or to slackening in the standards of food handling. T h e human carrier is rare, but the convalescent case often acts as a carrier for a period of several months. T h e remedy in the animal kingdom is difficult since the organism infects so many animals and, therefore, our main protective efforts should be aimed a.t protection of foodstuffs, the clean handling of them combined with adequate cooking. In H a m Green Hospital we had 38 of these cases last year and 20 in 1949.
(3) Brucellosis T h e main reservoir of this disease in this country is the cow. I see usually three to six cases of abortus fever a year. T h e disease is often unrecognised and takes the form of erratic pyrexia of unknown origin and in such circumstances is probably much commoner than suspected. T h e new drugs, particularly chloromycetin, hold out a more favourable future for treatment, and the veterinary control of cattle should ultimately reduce the danger to a minimum. Since the disease is spread largely by milk, the purity of that product comes under survey.
(4) WeU's Disease We admit two to three of these cases per year, all isolated cases, but I was personally involved in a small outbreak in Lanarkshire before the war. In that particular instance miners were infected by rats living in a wet pit and the organism was recovered from food tins which had attracted rats. It is worth while remembering that this is an occupational disease and the coroner is interested in any deaths which occur. Infectivity is high and it is strange that we do not see more cases. Control of the disease lies in the control of rats.
(5) Canicola Fever This disease might almost be called " Bristol Fever," since I believe that the longest list of human eases recorded in Great Britain has been gathered in this city. Perhaps 40% of British dogs are infected and I feel sure that many more human cases would come to light if they were but sought. T h e disease is, generally speaking, mild, with some encephalitic symptoms, conjunctivitis and iridocyclitis. At H a m Green Hospital we have now seen 17 cases in the past three years. Since the disease is so very prevalent among dogs and since dogs are so very much a part of our life and since often the disease is asymptomatic in the dog, control is likely to be difficult.
(6) Anthrax #Paper read to the West of England Branch Society of Medical Officers, Bristol, April 7th, 1951.
I have seen six cases of cutaneous anthrax all of which were mild and all occurring in animal workers. During t h e
193
PUBLIC HEALTH, July, 1951 war, in Aleppo, I saw m a n y cows a n d s h e e p b a d l y affected. T h e s e animals b e l o n g e d to the British A r m y a n d we took every p r e c a u t i o n to try to limit t h e s p r e a d of t h e disease. T h e a n i m a l s were s l a u g h t e r e d a n d b u r i e d i n lime. Despite this t r e a t m e n t local A r a b s d u g u p t h e animals a n d we f o u n d later ate the m e a t a n d actually sold some of it to local hotels, yet despite all this we could n o t trace a single h u m a n case. (7) Tetanus A p p r o x i m a t e l y o n e case of t e t a n u s is a d m i t t e d to H a m G r e e n H o s p i t a l p e r year. It has b e e n said t h a t t e t a n u s is not so p r e v a l e n t n o w as it was w h e n the horse was in greater use, b u t , indeed, the disease, i n civil practice, has n e v e r been very common. D u r i n g the war, however, one feels little d o u b t t h a t p r e v e n t i v e c o n t r o l b y m e a n s of toxoid inoculations was of t h e greatest value. (8) Actinomycosls W e have h a d two p u l m o n a r y cases d u r i n g the last four years, b o t h of t h e m i n m e n w o r k i n g w i t h cows. T h e disease is n o t v e r y c o m m o n b u t is w o r t h r e m e m b e r i n g in d o u b t f u l p u l m o n a r y infections. Penicillin has increased the chances of recovery a n d cure.
(9) Q Fever Last year we s t u m b l e d o n a solitary case of this disease, a n d one of m y colleagues w r o t e t h e details for p u b l i c a t i o n . I n a d d i t i o n to t h a t case w e f o u n d evidence of p r e v i o u s infection in a m e a t w o r k e r in Bristol. T h e r e h a v e n o w b e e n cases of this disease all over the s o u t h of E n g l a n d a n d t h e r e was a m i n o r hospital o u t b r e a k in L o n d o n . T h e disease was n o t e d for the first time in 1935 in Australia, a n d has since b e e n recognised all over the world. I m y s e l f saw it for the first time in Italy in 1944. It usually p r o d u c e s a n a t y p i c a l p n e u m o n i a . T h e Rickettsia s e e m s capable of s u r v i v i n g i n various d o m e s t i c animals, a n d e v e n in d u s t . I feel sure we shall p r o b a b l y see m o r e of this disease as it b e c o m e s m o r e readily recognisable.
(10) Plague I saw cases of this disease i n Jaffa, Haifa a n d Suez d u r i n g the war. T h e control, o f course, lies in t h e control of rats, since it is p r i m a r i l y a n epizootic. M y firmest i m p r e s s i o n of the disease was its ability to s m o u l d e r on a n d o n despite control. In H a i f a I c a n well r e m e m b e r extensive rat dest r u c d o n b e i n g u n d e r t a k e n for 18 m o n t h s after t h e last h u m a n case a n d yet a n o t h e r h u m a n case developed s h o r t l y after these d e r a t i z a t i o n m e a s u r e s were stopped. T h i s is a disease w h i c h could get loose in this c o u n t r y as it has d o n e in the past.
(11) Murine Typhus I have seen m u r i n e t y p h u s in the M i d d l e East d u r i n g t h e war. T h e disease occurs in a m i l d i s h f o r m a n d is carried b y the fleas of rats a n d mice. T h e r e is every possibility, a l t h o u g h it h a s n o t b e e n p r o v e d , t h a t the Rickettsia mooseri m u t a t e s w i t h prowazeki, a n d this m u t a t i o n m i g h t explain some of t h e reservoir p r o b l e m s of e p i d e m i c t y p h u s .
(12) Relapsing Fever Relapsing fever, a l t h o u g h n o t c o m m o n in this c o u n t r y , can involve a wide variety o f a n i m a l s a n d insects. I saw cases i n Syria, t h e reservoir a p p a r e n t l y b e i n g a m o n g s t bats i n caves, a n d similarly i n the W e s t e r n D e s e r t I saw two cases w h e r e t h e o r g a n i s m h a d b e e n t r a n s f e r r e d b y owl ticks.
(t3) Leishmaniasis T h i s disease was e x c e e d i n g l y c o m m o n i n its c u t a n e o u s variety in the L e v a n t , a n d it was i m p o s s i b l e to avoid seeing cases in every A r a b village in Syria. Dogs a n d d i r t s e e m to c o n t r i b u t e equally to the s p r e a d of t h e disease. I n D a l m a t i a I saw a n u m b e r of cases of viseraI leishmaniasis, t h e s p r e a d o f w h i c h was i n d o u b t .
(14) Rabies I n Palestine I saw one h u m a n case, a n A r a b b o y w h o h a d b e e n b i t t e n b y a jackal. I n t h e same c o u n t r y I saw several dogs suffering f r o m rabies a n d m y i m p r e s s i o n of t h e a n i m a l s
was t h a t t h e y were obviously ill, b u t n o t m a d in t h e dccepted p o p u l a r sense.
(15) Tox0plasm0sls D r . A. M . G . C a m p b e l l r e c e n t l y M e d i c o C h i r u r g i c a l Society, Bristol, a b l e family incidence of this disease a result of u n c o v e r i n g one case. T h e be congenital. I t p r o d u c e s a rash n o t unlike syphilis.
gave a lecture to the describing a remarkw h i c h h e e x p l o r e d as disease is rare a n d can a n d facial a p p e a r a n c e
(16) Chorio-Menlngitis I feel t h a t this disease is p r o b a b l y not so c o m m o n as was f o r m e r l y t h o u g h t , and cases s h o u l d n o t be d i a g n o s e d unless checked serologically. T h e r e has b e e n a t e n d e n c y to label o t h e r w i s e u n d i a g n o s e d cases of e n c e p h a l i t i s as chorio m e n ingitis, b u t it is n o w k n o w n t h a t o t h e r infections, for e x a m p l e m u m p s , c a n p r o d u c e a similar picture.
(17) Cow P0x I h a v e seen t w o cases of this disease r e s u l t i n g in a mild d e r m a t i t i s of the h a n d s . A similar sort o f disease is m e t w i t h s o m e t i m e s in the course of v a c c i n a t i o n a n d I r e m e m b e r a woman, who, u n - v a c c i n a t e d herself, t h o u g h t fit to suck h e r b a b y ' s vaccination a n d developed a serious lesion of h e r m o u t h a n d nose.
(18) Psittacosis I have seen five cases of this disease, two in S c o t l a n d in 1939, the i n f e c t i o n h a v i n g b e e n passed o n b y b u d g e r i g a r s , a n d t h r e e in Bristol d u r i n g the p a s t year, t h e infection h a v i n g b e e n t r a c e d to local wild a n d t a m e pigeons. T h i s infection is p r o b a b l y c o m m o n e r t h a n is s u s p e c t e d a n d certainly occurs in q u i t e a wide v a r i e t y of birds, some of w h i c h , t h e psittacines, are m o r e liable to t h e infection t h a n others. All the cases t h a t I h a v e seen p r o d u c e d atypical types of p n e u m o n i a a n d were all quite ill. O c c u r r e n c e of the disease a m o n g fulmars i n t h e Faroes is a n i n t e r e s t i n g i n d i cation of the prevalence of the disease a m o n g birds.
(19) Louping Ill Cases o f this disease, s h o w i n g encephalitis, have b e e n d i s c o v e r e d in Scotland. I t is n o t c o m m o n a n d so far seems to be limited to p e r s o n s w o r k i n g a m o n g s h e e p in the B o r d e r districts, b u t t h e r e is n o real r e a s o n w h y it s h o u l d n o t s p r e a d farther.
(20) Foot and Mouth Disease I have seen in Syria I saw of t h e h a n d s . common and
no cases of this disease in this c o u n t r y , b u t several cases w h i c h s h o w e d vesicular lesions A m o n g cattle in Syria t h e disease is v e r y almost disregarded.
(21) The Worms Cases of w o r m infection crop u p at intervals a n d we m a y at a n y t i m e see tape w o r m , h y d a t i d , trichineUa, a n d r o u n d w o r m infestation. O n e p a r t i c u l a r case of r o u n d w o r m i n f e s t a t i o n was a d m i t t e d to H a m G r e e n H o s p i t a l two years ago a n d a p p e a r e d as a n acute a b d o m i n a l c o n d i t i o n . I n fact, at operation, it was discovered t h a t the r o u n d w o r m had" p e n e t r a t e d i n t o the p a n c r e a t i c duct, c a u s e d a n acute p a n c r e a t i t i s w h i c h resolved w h e n the w o r m was p u s h e d d o w n into t h e intestine. T h e w o r m , a f t e r r e c o v e r y of the patient, was recovered w i t h a n t h e l m i n t i c s . I n Palestine I saw m a n y cases of r o u n d w o r m i n f e s t a t i o n a n d in p a r t i c u l a r a small A r a b b o y w h o h a d a n intestinal o b s t r u c t i o n caused b y a collection of w o r m s n u m b e r i n g o v e r 200. T h i s is m y experience. I h o p e to e x t e n d it farther. I feel sure we are all going to see m o r e of t h e s e diseases in that t h e y are g o i n g to be recognised, a n d this applies especially to Q fever. T h e E a s t e r n , W e s t e r n or V e n e z u e l a n e q u i n e e n c e p h a l o myelitis m i g h t appear in this c o u n t r y at a n y t i m e as horses m o v e across the Atlantic. I n 1924 J a p a n e s e B e n c e p h a l i t i s killed 3,800 o u t of 6,000 cases in T o l d o a n d t h e r e is talk o f similar disease in K o r e a
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PUBLIC HEALTH, July, 1931
now. O n e can b u t h o p e it will n o t arrive in t h e s e islands, b u t a n y t h i n g is possible in t h e s e days o f air travel. W i t h the d e v e l o p m e n t of virus bacteriology the i n t e r relation of living things suffering attack f r o m the same o r g a n i s m b e c o m e s steadily clearer. It is i n d e e d n o w advisable to e n q u i r e closely a b o u t habits, w o r k a n d animal contacts i n all cases of u n u s u a l infections. S u c h enquiries are the surest and quickest way to u n c o v e r s u r p r i s i n g infections and make one realise h o w c o m m o n u n c o m m o n things can be. T h u s far cart clinical control o f these diseases go. I n t h e field, each clinical case can be the p o i n t e r to a w i d e r area o f infection and control of the reservoir m a y b e c o m e possible. I n conclusion, I would b r i n g you back to the beginning. W e have b e e n c o n s i d e r i n g animals as sources o f h u m a n i n f e c t i o n s and I have p r e a c h e d o n this text to d e m o n s t r a t e the i m p o r t a n c e of this reservoir, h o w w i d e s p r e a d it is and h o w b y e n q u i r y w e can k n o w m o r e a b o u t it, or at least keep the possibility in m i n d t h a t the h o u s e h o l d dog can ke m o r e d a n g e r o u s t h a n he appears.
TABLF I. HUMAN INFECTIONS ASSOCIATED WITH ANIMALS.
Disease A--Bacterial Infections
Animal Reservoir
*Tuberculosis *Salmonellosis
... ...
*Brucellosis * W e l l ' s Disease *Canicola fever *Anthrax ...... *Tetanus *Ringworm *Actinomycosis *Q Fever . . . . . . Plague Murine Typhus Scrub Typhus Rocky Mountain Relapsing fever
... ... ...
Leishmaniasis *Toxoplasmosis Rat Bite fever Tularaemia
.,. ... .,. ...
... ... ... ...
*Chorio-meningitis * C o w p o x (vaccinia) *Psittacosis . . . . . . . . .
... ...
... ...
... ... ... ... ... ... ... ... ... ... ... ... ... .., ... fever ... ... ...
Cow, pig, m o n k e y , r o d e n t s . Cow, goat, sheep, rat, mouse, birds, cat, dog, etc. Cow, goat. Rat. Dog. Cow, goat, sheep, pig, etc. H e r b i v o r a generally. Horse, cow. Co',,,', horse. Cow, sheep, goat. Rat. Rat, mouse. Local rodents. Goat, local rodents. Owl, bat, r o d e n t s , m o n k e y foxes, jackal. Dog, local rodents. Rabbits. Rat. Rodents.
B--Virus Infections
* L o u p i n g Ill ...... * F o o t and M o u t h Disease * N e w c a s t l e Disease ... Rabies ......... Rickettsial pox ...... * O r f (Contagious P u s t u l a r Dermatitis) ...... Equine Encephalomyelitis Yellow fever ...... Rift Valley fever . . . . . . St. L o u i s Encephalitis ... J a p a n e s e B. Encephalitis Russian Spring-Summer Encephalitis ......
Mouse, monkey, rabbit, Cow. Parrots, b u d g e r i g a r , pigeon, fulmar, finch, duck, etc. Sheep.
Cow. D o m e s t i c fowl. Dog, wolf, cat, bat, deer, fox, cow, jackal, m o n goose. Mouse. Sheep. Horse, pigeon, rabbit, Monkey. Sheep. Fowls. Horse, goat, cow, Cow, rodents.
* T h e s e diseases occur in the U n i t e d K i n g d o m .
C--Protozoan, Helminth, Arthropod Infections Hookworm *Roundworm
...... ......
*Tape worm ...... * T r i c h i n e l l a spiralis *Echinococcus ...... Guinea worm ...... Clonorchis ...... Paragonimus :..... D e r m y s s u s gallmac Tunga penetrans . . . . . . *Giardia lamblia . . . . . . *Balantidi u m coli . . . . . .
...
...
Dog, cat. Rabbit, goat, sheep, pig, monkey. Cow, pig, fish, rat, dog. Pig, rat, lizard. Dog, cow, sheep, pig. Ox, dog, cat, horse, carnivores (Asian) Cat, dog, rat, mouse, fish. Dog, cat, pig. Fowls Cow, rodents. Rat, mouse. Pig.
BOOK REVIEWS Health Visiting. A Textbook for Health Visitor Students,
By MARGARET McEWAN, S.R.N., S.C.M. (Pp. 383. Price 18s. net.) L o n d o n : Faber & Faber. 1951. Textbooks on health visiting are sufficiently rare for any new production to be a welcome addition to the student's bookshelf. We must, therefore, extend a welcome to Margaret McEwan's 383 octavo pages. It is a valuable compendium of knowledge for the nurse who sets out to do health visiting and it will go some, if not the whole, way to satisfy the present demand. T h e book, as one of the first of its kind, has a number of weaknesses which subsequent editions should remedy. One of these arises from the unreal distinction drawn between the two parts into which the book is divided, namely, " Health Visiting " and " Health and Social Welfare Services and their Administration." The first part, " Health Visiting " (after an introductory chapter on history), is in effect an account of the health visitor in the maternity and child welfare field; a very good account in six chapters (including one on the family and one on statistics). The second part, " Health and Social Welfare Services and their Administration," has ten chapters covering the major services, including administration, the care of the deprived child and social welfare, as well as the school health service, the tuberculosis service, the V.D. service, and the mental health service. Thus, health visiting is presented in the main as a subject for the mother and her young child and the wider aspect of health visiting in relation to the total socio-medical needs of the family is given little emphasis. In general the book finds its weakest point in not outlining clearly the principles, aims and purpose of health visiting. This failure leads to others ; there is nowhere any statement of the relationship of the health visitor to the family doctor, although this is one of the burning problems of medicine to-day ; nor would the student reader grasp that she must work as a member of a team under the direction of the Medical Officer of Health. The chapter on the family needs to be strengthened in its account of the problem family and the unmarried mother. T h e chapter on tuberculosis is heavily weighted with clinical material which gives a wholly wrong emphasis to a social disease. T h e chapter on venereal diseases is also weak on the social aspects of the disease, which is the point at which it should be strongest. The book does not adequately deal with health visiting as an adjunct of general practice, the " giving of advice to persons in sickness," nor does it deal with hospital health visiting in relation to care and after care of the hospital patient, or to the modern aspects of the aged and handicapped. By giving such a long list of weaknesses it is not intended to belittle the high quality of this pioneering venture which will find an eager reading public in all health visitors' training courses and, it is to be hoped, among those already engaged in the field.
The Supply 0f Water.
By T. H. P. VEAL, B.SC., A.M.I.C.E.
Second edition. (Pp. 276 ; 118 figs.) London : Chapman & Hall, Ltd. 1950. In the preparation of the second edition of this work (the first was published 19 years ago) the principal additions and alterations have been made in the chapters dealing with flood flow and water purification. T h e main object of the book is to provide information on the chief aspects of water engineering in some degree of greater detail than is contained in textbooks on hydraulics. This the author has accomplished with some success and the possessor of this book will have to hand concise information of yields of wells, estimation of flows of streams and rivers, measurement of rainfall, flow of water in pipes and channels and metering devices.
PUBLIC HEALTH, July, 1951
HUMAN INFECTIOUS DISEASES ASSOCIATED WITH ANIMALS* By JAMES MACRAE, M.D., F.R.F.P.S., D.P.H.,
Resident Physician, Ham Green Hospital and Sanatorium, Bristol It is not my purpose to lecture you about a number of obscure diseases but rather to speak of the very real relation animals have in the spread of human infections. I would like to consider first, and very briefly, the general method by which such infections continue to worry us. A living pathogenic organism must exist, it must have a reservoir to which it can retreat and it must have means of moving to and from the reservoir and the human case. T h e means of movement may be physical, as in respiratory infections, or it may be by the agency of insects ; or the organism may rely on chance, waiting patiently as a spore, as does the tetanus bacillus. It may be a combination of these. T h e reservoir of infection is often human but it can be insect, fish, reptile, bird or animal. While the whole chain is important, the reservoir factor is vital to the survival of the organism and, if it can be eliminated, infections as we know them could not flourish. Unless we know the reservoir there can be no adequate understanding of any infectious disease. Control of the reservoir offers the best chance of complete mastery of the disease. When the reservoir of infection is human there are obvious difficulties in exercising proper control. Should any other living thing constitute a harbourage for organisms then the possibilities are brighter. For a long time it has been known that animals can acquire certain human diseases and use has been made of this fact in the field of experimental medicine. Alternatively, animals can pass some of their own peculiar infections to man. In other words, there are animal reservoirs of disease and we can create others. In recent years knowledge of this thesis has broadened steadily, especially in the field of virus diseases, and now more than ever must we think seriously of the animal world when we seek the reservoirs of human disease. I do not propose to deal with excessively rare diseases, nor will I include the vast number of tropical infections which have animal or insect reservoirs. I have compiled a list of human diseases associated with animals. T h a t list is attached and it is by no means exhaustive. T h e World Health Organisation has recently classified 80 such diseases and calls them Zoonoses. A glance at my list, Table I, shows the probable magnitude of the whole problem. I propose to speak only of such of these infections as I have seen myself. Since my experience is limited, these are by no means uncommon.
(1) Tuberculosls It may be considered that the bovine bacillus causes some 10% of human tuberculosis and that 50% of the child abdominal infections come from the same origin. It is probable that 25% or more of the United Kingdom's dairy cows are infected with tuberculosis. Bovine pulmonary infection is comparatively uncommon in humans but the degree of bovine infection varies considerably from one part of the country to another. Owing to inadequate data regarding types of bacilli, accurate figures are not always available, but the possibility of bovine tuberculosis should always be at the forefront of one's mind. Tuberculous meningitis is not commonly caused by the bovine bacillus. I myself have seen seven cases in a total series of 164 followed in Scotland in the years before the war. It should be remembered that cattle can be infected by the human strain of bacillus and this particular danger can
occur even in the best conditions; indeed it very nearly happened in our hospital dairy herd when a new cowman was engaged and only discovered on routine examination to be suffering from active tuberculosis. T h e remedy lies in either wholesale slaughter of the infected animals or segregation of calves into tubercle free herds and, even if these things were done, one would still need to take constant care to avoid infection of the cattle by human cases.
(2) Salmonella Infections These infections are a progressively increasing cause of human enteritis. T h e y have an exceptionally wide animal reservoir and over 300 strains of the organism have already been identified. Some of you will probably remember Sir William Savage's recent talk on this subject in this university when he delivered his Long Fox lecture. This is the only enteric disease with an animal reservoir occurring in this country. In recent years the increasing prevalence of Salmonella infection might be due to increased bulk storage and, therefore, bulk contamination by mice and rats or to the import of unusual items such as dried egg, or to slackening in the standards of food handling. T h e human carrier is rare, but the convalescent case often acts as a carrier for a period of several months. T h e remedy in the animal kingdom is difficult since the organism infects so many animals and, therefore, our main protective efforts should be aimed a.t protection of foodstuffs, the clean handling of them combined with adequate cooking. In H a m Green Hospital we had 38 of these cases last year and 20 in 1949.
(3) Brucellosis T h e main reservoir of this disease in this country is the cow. I see usually three to six cases of abortus fever a year. T h e disease is often unrecognised and takes the form of erratic pyrexia of unknown origin and in such circumstances is probably much commoner than suspected. T h e new drugs, particularly chloromycetin, hold out a more favourable future for treatment, and the veterinary control of cattle should ultimately reduce the danger to a minimum. Since the disease is spread largely by milk, the purity of that product comes under survey.
(4) WeU's Disease We admit two to three of these cases per year, all isolated cases, but I was personally involved in a small outbreak in Lanarkshire before the war. In that particular instance miners were infected by rats living in a wet pit and the organism was recovered from food tins which had attracted rats. It is worth while remembering that this is an occupational disease and the coroner is interested in any deaths which occur. Infectivity is high and it is strange that we do not see more cases. Control of the disease lies in the control of rats.
(5) Canicola Fever This disease might almost be called " Bristol Fever," since I believe that the longest list of human eases recorded in Great Britain has been gathered in this city. Perhaps 40% of British dogs are infected and I feel sure that many more human cases would come to light if they were but sought. T h e disease is, generally speaking, mild, with some encephalitic symptoms, conjunctivitis and iridocyclitis. At H a m Green Hospital we have now seen 17 cases in the past three years. Since the disease is so very prevalent among dogs and since dogs are so very much a part of our life and since often the disease is asymptomatic in the dog, control is likely to be difficult.
(6) Anthrax #Paper read to the West of England Branch Society of Medical Officers, Bristol, April 7th, 1951.
I have seen six cases of cutaneous anthrax all of which were mild and all occurring in animal workers. During t h e
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PUBLIC HEALTH, July, 1951 war, in Aleppo, I saw m a n y cows a n d s h e e p b a d l y affected. T h e s e animals b e l o n g e d to the British A r m y a n d we took every p r e c a u t i o n to try to limit t h e s p r e a d of t h e disease. T h e a n i m a l s were s l a u g h t e r e d a n d b u r i e d i n lime. Despite this t r e a t m e n t local A r a b s d u g u p t h e animals a n d we f o u n d later ate the m e a t a n d actually sold some of it to local hotels, yet despite all this we could n o t trace a single h u m a n case. (7) Tetanus A p p r o x i m a t e l y o n e case of t e t a n u s is a d m i t t e d to H a m G r e e n H o s p i t a l p e r year. It has b e e n said t h a t t e t a n u s is not so p r e v a l e n t n o w as it was w h e n the horse was in greater use, b u t , indeed, the disease, i n civil practice, has n e v e r been very common. D u r i n g the war, however, one feels little d o u b t t h a t p r e v e n t i v e c o n t r o l b y m e a n s of toxoid inoculations was of t h e greatest value. (8) Actinomycosls W e have h a d two p u l m o n a r y cases d u r i n g the last four years, b o t h of t h e m i n m e n w o r k i n g w i t h cows. T h e disease is n o t v e r y c o m m o n b u t is w o r t h r e m e m b e r i n g in d o u b t f u l p u l m o n a r y infections. Penicillin has increased the chances of recovery a n d cure.
(9) Q Fever Last year we s t u m b l e d o n a solitary case of this disease, a n d one of m y colleagues w r o t e t h e details for p u b l i c a t i o n . I n a d d i t i o n to t h a t case w e f o u n d evidence of p r e v i o u s infection in a m e a t w o r k e r in Bristol. T h e r e h a v e n o w b e e n cases of this disease all over the s o u t h of E n g l a n d a n d t h e r e was a m i n o r hospital o u t b r e a k in L o n d o n . T h e disease was n o t e d for the first time in 1935 in Australia, a n d has since b e e n recognised all over the world. I m y s e l f saw it for the first time in Italy in 1944. It usually p r o d u c e s a n a t y p i c a l p n e u m o n i a . T h e Rickettsia s e e m s capable of s u r v i v i n g i n various d o m e s t i c animals, a n d e v e n in d u s t . I feel sure we shall p r o b a b l y see m o r e of this disease as it b e c o m e s m o r e readily recognisable.
(10) Plague I saw cases of this disease i n Jaffa, Haifa a n d Suez d u r i n g the war. T h e control, o f course, lies in t h e control of rats, since it is p r i m a r i l y a n epizootic. M y firmest i m p r e s s i o n of the disease was its ability to s m o u l d e r on a n d o n despite control. In H a i f a I c a n well r e m e m b e r extensive rat dest r u c d o n b e i n g u n d e r t a k e n for 18 m o n t h s after t h e last h u m a n case a n d yet a n o t h e r h u m a n case developed s h o r t l y after these d e r a t i z a t i o n m e a s u r e s were stopped. T h i s is a disease w h i c h could get loose in this c o u n t r y as it has d o n e in the past.
(11) Murine Typhus I have seen m u r i n e t y p h u s in the M i d d l e East d u r i n g t h e war. T h e disease occurs in a m i l d i s h f o r m a n d is carried b y the fleas of rats a n d mice. T h e r e is every possibility, a l t h o u g h it h a s n o t b e e n p r o v e d , t h a t the Rickettsia mooseri m u t a t e s w i t h prowazeki, a n d this m u t a t i o n m i g h t explain some of t h e reservoir p r o b l e m s of e p i d e m i c t y p h u s .
(12) Relapsing Fever Relapsing fever, a l t h o u g h n o t c o m m o n in this c o u n t r y , can involve a wide variety o f a n i m a l s a n d insects. I saw cases i n Syria, t h e reservoir a p p a r e n t l y b e i n g a m o n g s t bats i n caves, a n d similarly i n the W e s t e r n D e s e r t I saw two cases w h e r e t h e o r g a n i s m h a d b e e n t r a n s f e r r e d b y owl ticks.
(t3) Leishmaniasis T h i s disease was e x c e e d i n g l y c o m m o n i n its c u t a n e o u s variety in the L e v a n t , a n d it was i m p o s s i b l e to avoid seeing cases in every A r a b village in Syria. Dogs a n d d i r t s e e m to c o n t r i b u t e equally to the s p r e a d of t h e disease. I n D a l m a t i a I saw a n u m b e r of cases of viseraI leishmaniasis, t h e s p r e a d o f w h i c h was i n d o u b t .
(14) Rabies I n Palestine I saw one h u m a n case, a n A r a b b o y w h o h a d b e e n b i t t e n b y a jackal. I n t h e same c o u n t r y I saw several dogs suffering f r o m rabies a n d m y i m p r e s s i o n of t h e a n i m a l s
was t h a t t h e y were obviously ill, b u t n o t m a d in t h e dccepted p o p u l a r sense.
(15) Tox0plasm0sls D r . A. M . G . C a m p b e l l r e c e n t l y M e d i c o C h i r u r g i c a l Society, Bristol, a b l e family incidence of this disease a result of u n c o v e r i n g one case. T h e be congenital. I t p r o d u c e s a rash n o t unlike syphilis.
gave a lecture to the describing a remarkw h i c h h e e x p l o r e d as disease is rare a n d can a n d facial a p p e a r a n c e
(16) Chorio-Menlngitis I feel t h a t this disease is p r o b a b l y not so c o m m o n as was f o r m e r l y t h o u g h t , and cases s h o u l d n o t be d i a g n o s e d unless checked serologically. T h e r e has b e e n a t e n d e n c y to label o t h e r w i s e u n d i a g n o s e d cases of e n c e p h a l i t i s as chorio m e n ingitis, b u t it is n o w k n o w n t h a t o t h e r infections, for e x a m p l e m u m p s , c a n p r o d u c e a similar picture.
(17) Cow P0x I h a v e seen t w o cases of this disease r e s u l t i n g in a mild d e r m a t i t i s of the h a n d s . A similar sort o f disease is m e t w i t h s o m e t i m e s in the course of v a c c i n a t i o n a n d I r e m e m b e r a woman, who, u n - v a c c i n a t e d herself, t h o u g h t fit to suck h e r b a b y ' s vaccination a n d developed a serious lesion of h e r m o u t h a n d nose.
(18) Psittacosis I have seen five cases of this disease, two in S c o t l a n d in 1939, the i n f e c t i o n h a v i n g b e e n passed o n b y b u d g e r i g a r s , a n d t h r e e in Bristol d u r i n g the p a s t year, t h e infection h a v i n g b e e n t r a c e d to local wild a n d t a m e pigeons. T h i s infection is p r o b a b l y c o m m o n e r t h a n is s u s p e c t e d a n d certainly occurs in q u i t e a wide v a r i e t y of birds, some of w h i c h , t h e psittacines, are m o r e liable to t h e infection t h a n others. All the cases t h a t I h a v e seen p r o d u c e d atypical types of p n e u m o n i a a n d were all quite ill. O c c u r r e n c e of the disease a m o n g fulmars i n t h e Faroes is a n i n t e r e s t i n g i n d i cation of the prevalence of the disease a m o n g birds.
(19) Louping Ill Cases o f this disease, s h o w i n g encephalitis, have b e e n d i s c o v e r e d in Scotland. I t is n o t c o m m o n a n d so far seems to be limited to p e r s o n s w o r k i n g a m o n g s h e e p in the B o r d e r districts, b u t t h e r e is n o real r e a s o n w h y it s h o u l d n o t s p r e a d farther.
(20) Foot and Mouth Disease I have seen in Syria I saw of t h e h a n d s . common and
no cases of this disease in this c o u n t r y , b u t several cases w h i c h s h o w e d vesicular lesions A m o n g cattle in Syria t h e disease is v e r y almost disregarded.
(21) The Worms Cases of w o r m infection crop u p at intervals a n d we m a y at a n y t i m e see tape w o r m , h y d a t i d , trichineUa, a n d r o u n d w o r m infestation. O n e p a r t i c u l a r case of r o u n d w o r m i n f e s t a t i o n was a d m i t t e d to H a m G r e e n H o s p i t a l two years ago a n d a p p e a r e d as a n acute a b d o m i n a l c o n d i t i o n . I n fact, at operation, it was discovered t h a t the r o u n d w o r m had" p e n e t r a t e d i n t o the p a n c r e a t i c duct, c a u s e d a n acute p a n c r e a t i t i s w h i c h resolved w h e n the w o r m was p u s h e d d o w n into t h e intestine. T h e w o r m , a f t e r r e c o v e r y of the patient, was recovered w i t h a n t h e l m i n t i c s . I n Palestine I saw m a n y cases of r o u n d w o r m i n f e s t a t i o n a n d in p a r t i c u l a r a small A r a b b o y w h o h a d a n intestinal o b s t r u c t i o n caused b y a collection of w o r m s n u m b e r i n g o v e r 200. T h i s is m y experience. I h o p e to e x t e n d it farther. I feel sure we are all going to see m o r e of t h e s e diseases in that t h e y are g o i n g to be recognised, a n d this applies especially to Q fever. T h e E a s t e r n , W e s t e r n or V e n e z u e l a n e q u i n e e n c e p h a l o myelitis m i g h t appear in this c o u n t r y at a n y t i m e as horses m o v e across the Atlantic. I n 1924 J a p a n e s e B e n c e p h a l i t i s killed 3,800 o u t of 6,000 cases in T o l d o a n d t h e r e is talk o f similar disease in K o r e a
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now. O n e can b u t h o p e it will n o t arrive in t h e s e islands, b u t a n y t h i n g is possible in t h e s e days o f air travel. W i t h the d e v e l o p m e n t of virus bacteriology the i n t e r relation of living things suffering attack f r o m the same o r g a n i s m b e c o m e s steadily clearer. It is i n d e e d n o w advisable to e n q u i r e closely a b o u t habits, w o r k a n d animal contacts i n all cases of u n u s u a l infections. S u c h enquiries are the surest and quickest way to u n c o v e r s u r p r i s i n g infections and make one realise h o w c o m m o n u n c o m m o n things can be. T h u s far cart clinical control o f these diseases go. I n t h e field, each clinical case can be the p o i n t e r to a w i d e r area o f infection and control of the reservoir m a y b e c o m e possible. I n conclusion, I would b r i n g you back to the beginning. W e have b e e n c o n s i d e r i n g animals as sources o f h u m a n i n f e c t i o n s and I have p r e a c h e d o n this text to d e m o n s t r a t e the i m p o r t a n c e of this reservoir, h o w w i d e s p r e a d it is and h o w b y e n q u i r y w e can k n o w m o r e a b o u t it, or at least keep the possibility in m i n d t h a t the h o u s e h o l d dog can ke m o r e d a n g e r o u s t h a n he appears.
TABLF I. HUMAN INFECTIONS ASSOCIATED WITH ANIMALS.
Disease A--Bacterial Infections
Animal Reservoir
*Tuberculosis *Salmonellosis
... ...
*Brucellosis * W e l l ' s Disease *Canicola fever *Anthrax ...... *Tetanus *Ringworm *Actinomycosis *Q Fever . . . . . . Plague Murine Typhus Scrub Typhus Rocky Mountain Relapsing fever
... ... ...
Leishmaniasis *Toxoplasmosis Rat Bite fever Tularaemia
.,. ... .,. ...
... ... ... ...
*Chorio-meningitis * C o w p o x (vaccinia) *Psittacosis . . . . . . . . .
... ...
... ...
... ... ... ... ... ... ... ... ... ... ... ... ... .., ... fever ... ... ...
Cow, pig, m o n k e y , r o d e n t s . Cow, goat, sheep, rat, mouse, birds, cat, dog, etc. Cow, goat. Rat. Dog. Cow, goat, sheep, pig, etc. H e r b i v o r a generally. Horse, cow. Co',,,', horse. Cow, sheep, goat. Rat. Rat, mouse. Local rodents. Goat, local rodents. Owl, bat, r o d e n t s , m o n k e y foxes, jackal. Dog, local rodents. Rabbits. Rat. Rodents.
B--Virus Infections
* L o u p i n g Ill ...... * F o o t and M o u t h Disease * N e w c a s t l e Disease ... Rabies ......... Rickettsial pox ...... * O r f (Contagious P u s t u l a r Dermatitis) ...... Equine Encephalomyelitis Yellow fever ...... Rift Valley fever . . . . . . St. L o u i s Encephalitis ... J a p a n e s e B. Encephalitis Russian Spring-Summer Encephalitis ......
Mouse, monkey, rabbit, Cow. Parrots, b u d g e r i g a r , pigeon, fulmar, finch, duck, etc. Sheep.
Cow. D o m e s t i c fowl. Dog, wolf, cat, bat, deer, fox, cow, jackal, m o n goose. Mouse. Sheep. Horse, pigeon, rabbit, Monkey. Sheep. Fowls. Horse, goat, cow, Cow, rodents.
* T h e s e diseases occur in the U n i t e d K i n g d o m .
C--Protozoan, Helminth, Arthropod Infections Hookworm *Roundworm
...... ......
*Tape worm ...... * T r i c h i n e l l a spiralis *Echinococcus ...... Guinea worm ...... Clonorchis ...... Paragonimus :..... D e r m y s s u s gallmac Tunga penetrans . . . . . . *Giardia lamblia . . . . . . *Balantidi u m coli . . . . . .
...
...
Dog, cat. Rabbit, goat, sheep, pig, monkey. Cow, pig, fish, rat, dog. Pig, rat, lizard. Dog, cow, sheep, pig. Ox, dog, cat, horse, carnivores (Asian) Cat, dog, rat, mouse, fish. Dog, cat, pig. Fowls Cow, rodents. Rat, mouse. Pig.
BOOK REVIEWS Health Visiting. A Textbook for Health Visitor Students,
By MARGARET McEWAN, S.R.N., S.C.M. (Pp. 383. Price 18s. net.) L o n d o n : Faber & Faber. 1951. Textbooks on health visiting are sufficiently rare for any new production to be a welcome addition to the student's bookshelf. We must, therefore, extend a welcome to Margaret McEwan's 383 octavo pages. It is a valuable compendium of knowledge for the nurse who sets out to do health visiting and it will go some, if not the whole, way to satisfy the present demand. T h e book, as one of the first of its kind, has a number of weaknesses which subsequent editions should remedy. One of these arises from the unreal distinction drawn between the two parts into which the book is divided, namely, " Health Visiting " and " Health and Social Welfare Services and their Administration." The first part, " Health Visiting " (after an introductory chapter on history), is in effect an account of the health visitor in the maternity and child welfare field; a very good account in six chapters (including one on the family and one on statistics). The second part, " Health and Social Welfare Services and their Administration," has ten chapters covering the major services, including administration, the care of the deprived child and social welfare, as well as the school health service, the tuberculosis service, the V.D. service, and the mental health service. Thus, health visiting is presented in the main as a subject for the mother and her young child and the wider aspect of health visiting in relation to the total socio-medical needs of the family is given little emphasis. In general the book finds its weakest point in not outlining clearly the principles, aims and purpose of health visiting. This failure leads to others ; there is nowhere any statement of the relationship of the health visitor to the family doctor, although this is one of the burning problems of medicine to-day ; nor would the student reader grasp that she must work as a member of a team under the direction of the Medical Officer of Health. The chapter on the family needs to be strengthened in its account of the problem family and the unmarried mother. T h e chapter on tuberculosis is heavily weighted with clinical material which gives a wholly wrong emphasis to a social disease. T h e chapter on venereal diseases is also weak on the social aspects of the disease, which is the point at which it should be strongest. The book does not adequately deal with health visiting as an adjunct of general practice, the " giving of advice to persons in sickness," nor does it deal with hospital health visiting in relation to care and after care of the hospital patient, or to the modern aspects of the aged and handicapped. By giving such a long list of weaknesses it is not intended to belittle the high quality of this pioneering venture which will find an eager reading public in all health visitors' training courses and, it is to be hoped, among those already engaged in the field.
The Supply 0f Water.
By T. H. P. VEAL, B.SC., A.M.I.C.E.
Second edition. (Pp. 276 ; 118 figs.) London : Chapman & Hall, Ltd. 1950. In the preparation of the second edition of this work (the first was published 19 years ago) the principal additions and alterations have been made in the chapters dealing with flood flow and water purification. T h e main object of the book is to provide information on the chief aspects of water engineering in some degree of greater detail than is contained in textbooks on hydraulics. This the author has accomplished with some success and the possessor of this book will have to hand concise information of yields of wells, estimation of flows of streams and rivers, measurement of rainfall, flow of water in pipes and channels and metering devices.