380 AND DISEASE

ANIMAL PARASITES AND HUMAN DISEASES

By Paul C. Beaver, Ph.D. Department of Tropical Medicine and Public Health, Tulane University School of Medicine

P A1IASITES fall only roughly into the two directed to parasitic infections caused by categories implied in the title of this worms which, regardless of length of resi- discussion. While a few of them arc totally dence in the human body, do not reach full dependent upon htmman hosts, and some are reproductive maturity and are therefore not able to develop only in other animals, a diagnosable by the usual laboratory majority of the parasites commonly re- methods. It is of course the larval stages ferred to as “parasites of man” are in or immature adults that arc involve(! amid!, reality parasites of other animals.1 In the owing to their tendency to be mostly in the latter grouip are such familiar examples as tissues and in many instances difficult to Trichinella, found in rats and many other find and identify, the infections caused by animals, including pigs; Balantidium and them are often unrecognized. Largely for some lesser protozoa of pigs; Toxoplasma, this reason the frequency and severity of which occurs in many wild and domesti- infections of this nature have not been cated animals. Trypanosoma cnuzi, which is fully determined. There are, however, some carried by a variety of animals, is the cause familiar examples. of Chagas’ disease commonly seen in parts Certain well known larval tapeworm in- of South America and found recently in a fections are acquired from other animals. child in Texas.2 Other examples include Examples are echinococcus (hydatid) and Isospora of undetermined hosts, possibly in- coenunuis whose infective stages are carried cluding the dog; species in the feces of dogs, and sparganuim which that commonly are found in sheep and comes from infected cats and (logs hut ne- goats; the small tapeworms, Hymenolepis quines development in aquatic hosts before nana and Hmcnolepis diminuta, of rats it is infective for man. These infections arc and mice; and! the common dog tapeworm, uncommon in the United States and are Dipylidium caninum. There arc others especially rare in children. whose endemicity in any area depends It is sometimes stated! that the comiimon somewhat on the presence of suitable non- ascarids and whipworms of children human hosts, and still others that are able (Ascanis lumbnicoides and Tnichuiris tn- to reach maturity in man but are rarely chiura) are identical with those of pigs. It involved in medical problems because in- has not been satisfactorily demonstrated fection is acquired only by eating uncooked that they are cross-infective to the extent earthworms and insects. It might be men- of reaching full maturity in the reciprocal tioned, as a matter of interest, that occa- hosts, but it can be safely assumed that siona!ly other animals may acquire pana- when children swallow the infective eggs sitic diseases from their human associates, of pig ascaris, the larvae invade the liver as for example dysentery and diarrhea in and the lungs even if they fail to reach ma- dogs, caused by Entamoeba histolytica and tumrity in the intestine. Strongyloides sterconalis. Creeping eruption, or cutaneous larva In all of the above mentioned parasitic migrans, has been recognized for many infections, diagnosis is usually based on con- years as due to larval stages of the dog and ventional laboratory methods, and both cat , Ancylostoma brazihiense. It clinical and laboratory workers are gen- is not always appreciated, however, that erally familiar with the problems presented other species of ncmatode larvae also pro- by them. Iii recent ‘ears attention has been ducc creeping eruption, and that after a

ADDRESS: New Orleans, Louisiana.

Downloaded from www.aappublications.org/news by guest on October 1, 2021 AMERICAN ACADEMY OF PEDIATRICS - PROCEEDINGS 381

period of migration in the outer layers of other indications of infection gradually the skin some of the larvae move into disappear. Conclusive diagnosis can be deeper tissues, including the lungs.3 made only by direct demonstration of larvae Among those infections acquired through in liver tissue or in other tissues post contact with dogs and cats in the United mortem. Usually a satisfactory diagnosis States, it is believed that visceral larva mi- can be made on clinical grounds, especially grans, caused by ascarids of dogs, is proba- if supported by senodiagnostic tests pres- l)lV the most widespread and most damag- ently being developcd.#{176}2 imig to children. Although this infection Toxocara is the only larval yet )rolmbly has been common among tOddler- identified in the tissues of children with age children for many years, it was not . It is anticipated, recognized amid described until 1952. however, that others will he discovered. It During the past 5 years much has been was mentioned earlier that dog and cat written about visceral larva migrans and hookworm larvae that cause creeping erup- case reports, including some fatalities, have tion also invade the deeper tissues. Their appeare! abundantly in pediatric jour- behavior in experimental animals suggests nals. s It will therefore suffice merely to that several species of not review 5OC of its main features. The para- ordinarily infesting man probably behave site, Toxocara, is a large roundworm which somewhat like Toxocara in humans and in its appearance amid life cycle resembles may therefore produce the visceral larva Ascaris lumbricoidles, the commiion large migrans type of disease. Studies by Nichols roundworm of children. The dog and the have made it possible to identify some of cat each comiimm)nly harbors a species of its these larvae either after isolation from fresh own, T. canis amid T cati, respectively. Eggs tissues or in stained sections.33’ ‘ Two of eliminated iii the aninials’ feces are not in- the Toxocara larvae recently identified in fective when passed but after 2 or 3 weeks our laboratory arc noteworthy. One (to be iii warm, dLIni1), shaded soil each egg, of reported from California by Dr. A. R. which there may be hundreds in 1 or 2 gm Irvine) was the first to be found in the eye of soil, comitains an infective larva capable since Wilder reported a series of sumch cases of prodtmcing a new mature infection in a in 1950;15 and the other (reported a few natural host, or a long-lasting larval infec- months ago from Washington, D.C. by tion in a child. When infective eggs are in- Bruton and Jaffurs16) was the first to be gested I)y children, the larvae erupt from found in a needle biopsy. the egg, migrate to the liver, and from there Biopsies of the liver for diagnosis of to other parts of the body including the cen- suispected cases of visceral larva migrans tral nervous system and the eye. Destructive have revealed three infections of Capillania eosinophi!ic granulomatous lesions are hepatica in children-one each in Balti- formed! aroundi the minute worms or along more,17 Hawaii’8 and Souith Afnica.19 Nec- their migratory paths through the tissues. ropsy examination earlier had brought to Marked eosinophilia of the blood, hypcr- light only three such cases, one of which globuhinemia and enlargement of the liver was in a child in New Orleans.2#{176} This are characteristically noted!, along with worm’s natural location is in the liver of variable symptoms including fever, cough, rats and other small rodents, and it has the loss of appetite, irritability and neumnologic peculiar trait of putting its eggs in the (histurbamices. Threatening lesions in the tissues where they can not be eliminated eve bearing a superficial resemblance to from the body. Capillania has not been ade- retimioblastoma have occurred in a number quately stu(lied but it appears probable that of instances. Larvae Persist alive in the human imifection is acquired! through the in- tissues for many months, dumning which time gcstion of soil contaminated by animals the eosinophilia may remain high while the whose feces bear the eggs digested from the

Downloaded from www.aappublications.org/news by guest on October 1, 2021 :382 ANIMALS AND DISEASE liver of infected rats. Like Toxocara, the about the frequency and clinical importance eggs must undergo development outside the of infection with immature stages of this host before they are infective. Clinically, common parasite. Indeed its possible role in Capillania infection can not be distinguished dyscntenies of unknown cause in children from visceral larva migrans caused by has already been considered by the speaker, Toxocara. Although it appears to be an as it must also have by others. There arc uncommon infection in children it seems doubtless still some important parasitic dis- to be especially damaging since only one eases unidentified. Some of them may fill individual infected vith Capillaria is the gaps among the diseases of unknown on known to have survived, and even in this doubtful etiology, such as tropical eosino- case the child had not entirely recovered philia which, according to some prelimi- when the report was made.19 On the other nary reports, appears to be a non-patent hand, its real prevalence is unknown and ncmatode infection related to visceral larva it is possible that some clinically significant 627 but non-fatal infections arc being over- Since the nonpatent, cryptic parasitic looked. infections, especially the filth-borne, soil- One other type of zoonotic infection generated ones, are more common in chil- should be mentioned. In 1941 a worm dren than in adults, it is expected that new resembling the hcartworm of dogs (Dino- knowledge of these infections will come filaria) was discovered in the inferior vena from pediatricians who look for them. For- cava of a woman in New Onlcans.21 More tunately, there are certain common signals recently other filanial worms of the same which serve to alert the clinical and labora- general type have been found in subcutanc- tory observer. They are, somewhat in order oils nodules or abscesses in adult residents of their significance or frequency, cosino- of Florida. In addition to two reported in phihia of the blood, especially if high and

195222 and one in 1957,23 at least five un- sustained, liver enlargement, pneumonitis, reported cases have come to our attention bronchial asthma, urticania, neurologic dis- within the past year. These worms are tunbances, sharp deviations in behavior, several centinieters long and, although none intra-ocular granulomatous lesions, or sub- have been found mature amid reproductive, cutaneous cysts, masses, or swellings. With all have been fully differentiated. Thus far or without peripheral eosinophilia, hidden these worms have not been specifically parasitic infections of the intestine arc sug- identified audI the natural host is therefore gcsted by the presence of cosinophils and unknown. It is suspected that dogs carry Charcot-Leyden crystals in exudates of the the infection and that mosquitoes trans- bowel or in feces. mit it.23 The trend towards suburban and exurban Perhaps stress can justifiably be placed residence probably is encouraging more on the incompleteness of our knowledge of families to acquire household pets. At the the larval worm infections acquired from same time, better housing and general im- other animals, particularly household pets. provements in sanitation are bringing about A few years ago we might have said that a decrease in the prevalence of human para- ascarids of dogs and cats rarely if ever cause sitic infections transferred directly from in- disease iii child!ren, although warning on dividumal to individual. On the other hand, this matter had been given by Schwartz in modern implements and principles of sanita-

193221 and by others even earlier. Also, up tion have had relatively little influence on to a Tear ago we (lid not know that the dog the management and defecation habits of whiipworm, ‘irichuiris vulpis, ever infects household pets. This situation niay be iiIdfl. Now that Hall and Soiinenberg25 have bringing about an actual rise in the fre- reported infection with a mature worm in a quency of human disease contracted from child, we must immediately be curious these animals. It is certainly true that the

Downloaded from www.aappublications.org/news by guest on October 1, 2021 AMERICAN ACADEMY OF PEDIATRICS - PROCEEDINGS 383 control of other parasitic dliseases in some Larva miligrans. Exper. Parasitol., 5:587, communities has elevated the -borne 1956. infections to a position of much greater 4. Beaver, P. C., Snyder, C. I-I., Carrera, G. M., Dent, J. H., and Lafferty, J. W.: relative importance. This matter is men- Chronic eosinophilia dime to viscenal tioned to emphasize that while it may ap- larva mignans. Report of three cases. pear that the prevalence of zoonotic infec- PEDIATRICS, 9:7, 1952. tions among children is increasing, the ap- 5. Smith, M. H. D., and Beaver, P. C. : Vis- ceral larva mignans due to infection with Paremit increase is due, in part at least, to dog and cat ascanids. Pediat. Clin. North the greater ease with which these infections America, February, 1955, p. 163. cllTl be recognized in the absence of others 6. Platou, R. V., and Beaver, P. C. : Visceral that often produce many of the same larva migrans. Acta paediat., 46:64, symptoms. 1957. In conclusion, several of the parasites of 7. Dent, J. H., Nichols, R. L., Beaver, P. C., Camera, G. M., and Staggers, R. J.: animals, particularly household pets, are Visceral larva migrans; with a case re- known to cause serious diseases in chil- port. Am. J. Path., 32:777, 1956. dren. Other less damaging ones are readily 8. Kanpinski, F. E., Events-Suarez, E. A., amid transmissible to humans, and it can not Sawitz, W. G. : Larval gramiulomatosis be said with confidence that still others are (visceral larva migrans). Am. J. Dis. not responsible for certain diseases of un- Child., 92:34, 1956. 9. Heiner, D. C., and Kevy, S. V. : Visceral known cause. Moreover, even if certain larva migrans; report of the syndrome in parasites of pets are harmless to the human three siblings. New England J. Med., members of a household they may be harm- 254:629, 1956. fuml to the pets themselves. It would there- 10. Sadun, E. H., Norman, L., and Allain, D.: fore seem that from almost every reasonable The detection of antibodies to infections with the nematode, , a point of view parasites deserve much the causative agent of visceral larva migrans. same consideration whether they occur in Am. J. Tnop. Med., 6:562, 1957. children or in their childlike animal corn- 11. Kagan, I. G.: Senum-agar double diffusion panions. Finally, we must be reminded that studies with ascanis antigens. J. Infect. household pets have such values as to Dis., 101:11, 1957. entirely rule out any suggestion that they 12. Jung, R. C., and Pacheco, G. : Relationship of clinical features to immunologic reac- impose such responsibilities and involve tions in visceral larva migrans. In prepa- such hazards as to make them undesirable, ration. except in special cases. Though it is not a 13. Nichols, R. L. : The etiology of visceral simple matter, by preventive and thcna- larva migrans. I. Diagnostic morphology peutic measures, dogs and cats can be kept of infective second-stage Toxocara Ian- vae. J. Parasitol., 42:349, 1956. free of harmful parasites, or at least they 14. Nichols, R. L. : The etiology of visceral can be managed in such a way as to mini- larvae migrans. II. Comparative larval mize their threat to health. The same holds morphology of Ascaris lunthricoides, for other less common household pets, such , Strongyloides ster- as mice and monkeys. coralis and . J. Parasitol., 42:363, 1956. 15. Wilder, H. C. : Nematode endopthalmitis. REFERENCES Tr. Am. Acad. Ophth., 55:99, 1950. 16. Bruton, 0. C., and Jaffurs, W. J. : Larval

1 . Meyer, K. F. : The animal kingdom, a re- granulomatosis ; diagnosis by needle servoir of human disease. Ann. mt. Med., biopsy of the liver. U. S. Armed Forces 29:326, 1948. M. J., 8:1022, 1957. 2. Woody, N. C., and Woody, H. B. : Amen- 17. Otto, G. F., Benthrong, M., Applebv, R., can trypanosomiasis (Chagas’ disease). Rawlins, J., and Wilbur, 0. : Eosinophilia First indigenous case in the United and hepatomegaly due to Capillania States. J.A.M.A., 159:676, 1955. hepatica infection. Bull. Johmi Hopkins 3. Beaver, P. C. : Parasitological reviews. Hosp., 94:319, 1954.

Downloaded from www.aappublications.org/news by guest on October 1, 2021 384 ANIMALS AND DISEASE

18. Ewing, C. M., and Tilden, I. L.: Capil- of Dirofilaria. Ztschr. Tropenmed., 8:59, lana Ize/)atica. Report of fourth case of 1957. true human infection. J. Pediat., 48:341, 24. Schwartz, B. H. : Some parasites of dogs 1956. and cats transmissible to human beings 19. Cochraime, J. C., Sagorin. L., and Vilcocks, and domesticated animals. Vet. Alumni ,1. C. : Capillaria liepatica infection in Quart., Ohio State Univ., 20:5, 1932. man; a syndrome of extreme eosinophihia, 25. Hall, J. E., and Sonnenbeng, B. : An ap- hepatomegalv and hperglobulinaemia. parent case of human infection with the South African M. J., 31:751, 1957. whipwonm of dogs, Trichuris vulpis 20. McQuown, A. L. : Capiliaria hepatica: Re- (Fnoelich, 1789). J. Parasitol., 42:197, Port of geiiuine amid spurious cases. Am. 1956. J. Trop. Med., 30:761, 1950. 26. Danaraj, T. J., da Silva, L. S., and 21. Faust, E. C., Thomas, E. P., and Jones, J.: Schachen, J. F. : The filanial compliment- Discovery of human heartworm infection fixation test in eosinophilic lung (tropi- in New Orleans. J. Parasitol., 27:115, cal eosinophilia). A preliminary report. 1941. Proc. Alumni A., Malaya, 10:109, 1957. 22. Faust, E. C., et al.: Unusual findings of 27. Gault, E. W., amid Webb, J. K. G. : Tropical filanial infectiomis in mami. Am. J. Tnop. eosinophilia; hepatic lesions related to Me(l., 1:239, 1952. presence of nematode larvae. Lancet, 2:3. Faust, E. C. : Hurnami infection with species 2:471, 1957.

RICKETTSIAL DISEASES OF ANIMALS TRANSMISSIBLE TO CHILDREN

By Lauri Luoto, D.V.M., MPH. U. S. Departuient of health, Education and Welfare, Public Health Service, National Institutes of I!(’(lit/l, National Institute of Allergy and Infectious Diseases, Rocky Mountain Laboratory, Hamilton, Montana

B E(:AUSE rickettsial infections occuir spo- and characteristics of these diseases in chil- radically, pediatricians may iiot be as dren will be reviewed briefly. thoroughly familiar with them as they are Rocky Mountain spotted fever is usually with common diseases of children that are contracted during the spring or summer characterized by rash. Hence, the nickettsias through the bite of an infected tick a!- are infrequently consi(!ered in the etiology though infection also may be acquired by of febnile exanthemas or fevers of unde- dermal contact with tissues of a crushed termined origin. Rickettsial diseases of pni- or improperly removed tick. The wood tick, mary interest in this country are Rocky Denmacenton andersoni, the dog tick, D. Mountain spotted fever, mumrine typhus, vaniabilis, and the lone-star tick, Ambly- rickcttsialpox and Q fever. The agents omma americanum, which are found, re- causing these diseases exist as latent infec- spcctively, in the western, eastern, and tions in arthnopods and animals, and they southern United States arc responsible for are transmitted accidentally to man through transmitting the organism to man. Natumral well-defined channels of spread. An aware- infection with Rickcttsia nickettsii in these ness of the epizootiology of rickettsial dis- species is maintained by transovaria! pas- eases in nature and of the means by which sage of the agent and by the feeding of these agents are transmitted to man is help- immature stages on infected small mam- ful in establishing a d!iagnosis of a nickett- mals. Environmental factors such as rain- sial disease. Thenefone, salient features of fall, temperature, food supply of small the natural cycles of infection which may mammals, and prevalence of predators in- suggest a clinical diagnosis will be stressed, directly affect the abundance of ticks. The

ADDRESS: Rocky Mountain Laboratory, Public Health Service, Hamilton, Montana.

Downloaded from www.aappublications.org/news by guest on October 1, 2021 ANIMAL PARASITES AND HUMAN DISEASES Paul C. Beaver Pediatrics 1958;22;380

Updated Information & including high resolution figures, can be found at: Services http://pediatrics.aappublications.org/content/22/2/380 Permissions & Licensing Information about reproducing this article in parts (figures, tables) or in its entirety can be found online at: http://www.aappublications.org/site/misc/Permissions.xhtml Reprints Information about ordering reprints can be found online: http://www.aappublications.org/site/misc/reprints.xhtml

Downloaded from www.aappublications.org/news by guest on October 1, 2021 ANIMAL PARASITES AND HUMAN DISEASES Paul C. Beaver Pediatrics 1958;22;380

The online version of this article, along with updated information and services, is located on the World Wide Web at: http://pediatrics.aappublications.org/content/22/2/380

Pediatrics is the official journal of the American Academy of Pediatrics. A monthly publication, it has been published continuously since 1948. Pediatrics is owned, published, and trademarked by the American Academy of Pediatrics, 345 Park Avenue, Itasca, Illinois, 60143. Copyright © 1958 by the American Academy of Pediatrics. All rights reserved. Print ISSN: 1073-0397.

Downloaded from www.aappublications.org/news by guest on October 1, 2021