Volume 5 | Issue 4 Article 7

1943 Some Parasites of the Eric W. Isakson Iowa State College

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Recommended Citation Isakson, Eric W. (1943) "Some Parasites of the Dog," Iowa State University Veterinarian: Vol. 5 : Iss. 4 , Article 7. Available at: https://lib.dr.iastate.edu/iowastate_veterinarian/vol5/iss4/7

This Article is brought to you for free and open access by the Journals at Iowa State University Digital Repository. It has been accepted for inclusion in Iowa State University Veterinarian by an authorized editor of Iowa State University Digital Repository. For more information, please contact [email protected]. Sonle Parasites of the Dog

A study of the parasites less commonly encountered

Eric W. Isakson, fall' 43

RACTICALLY all veterinarians read­ beyond the fact that the larvae are P ily diagnose and treat in coughed up in the mucus from the tra­ the dog. Such parasites as , lice, ticks, chea and may pass out the mouth or be tapeworms, hookworms, and ascarids, are swallowed and pass with the feces. It is common and are dealt with routinely and thought, however, that the life cycle is quite effectively. However, there are a direct. great many more parasites of the dog, This parasite is not common, but has most of which do not receive much atten­ been reported from countries scattered tion until they appear under unusual cir­ throughout the world. In North America cumstances, and then are too often con­ its occurernce has also been rather scat­ sidered only as curiosities. This article tered. It has been reported in Canada, was written for the purpose of attracting New York, Texas, and Nebraska. attention to a few of the less common, The symptoms vary, as would be ex­ though far from rare, parasites of the pected, with the degree of infection and dog which have interesting and direct im­ the size of the nodules produced. If the portance to human hygiene, or which may infection is slight and the nodules are appear unexpectedly at post mortem ex­ small, there may be no symptoms except amination, causing confusion or bewilder­ a slight cough. As the nodules become ment in the mind of the examiner. larger the lumen of the respiratory pass­ age is decreased, respiration becomes la­ Respiratory Parasite bored, and the cough increases and be­ Oslerus osleri, often called a dog "lung­ comes persistent. Emaciation and loss of worm," is a parasite of the trachea, bron­ appetite are seen as the disease progresses. chi, and occasionally the lungs. It is The disease may become chronic and may found in nodular proliferations of the mu­ result in death. Diagnosis is made by a cosa, usually at the base of the primary bronchoscopic examination, by finding the bronchi. It is a rather small nematode. larvae in mucus obtained by swabbing the The male measures about 5 mm. in length posterior part of the pharynx, or by find­ and is quite slender while the female ing larvae in fresh feces. measures 9 to 15 mm. and is more robust. The presence of the parasite in the mucosa Treatment Symptomatic stimulates the growth of connective tis­ Only symptomatic treatment can be rec­ sue and thereby causes the formation of ommended because of the location of the tumor-like nodules which may be up to a parasites. Expectorants and cough reme­ centimeter in diameter, grayish in color, dies may relieve the symptoms. Monnig1 , and having a villous appearance due to relating the experience of Fillers, states the projecting ends of the worms. The that if the are kept free from rein­ parasite is ovoviviparous, the eggs hatch­ fection the worms may die and the nod­ ing in the uterus of the female. The larvae ules disappear in four or five months. Thus are blunt anteriorly and have a short S­ strict sanitation is recommended both for shaped tail. The life cycle is not known treatment and prophylaxis.

Spring, 1943 167 serrata, commonly referred he rubs his nose with his fore feet and to as the "tongue-worm" of the dog, is snores in his sleep. A blood-stained dis­ not a worm and is not a parasite of the charge from the nostrils may be observed tongue. The adult inhabits the nasal cav­ but is not constant. The parasite lives ity of the dog primarily and according to about fifteen months and then the animal Hall, is a legless arachnid. It has been recovers. It seldom if ever causes death reported rarely in man and in herbivorous of the host. . Diagnosis is made by the symptoms and The adult is elongated and somewhat by finding eggs in the nasal exudate or in worm-like with a broad anterior end, the feces. Occasionally the parasites are tapering body with a cross-striated ap­ found in the feed pan or watering pan, but pearance, and is flattened dorso-ventrally. this is the exception rather than the rule. There are four hooks at the anterior end The only treatment at present is trephin­ which are said to be remnants of the legs. ing and irrigating the nasal cavity. The male is 2 or 3 cm. long while the Pneumonyssus caninum, sometimes female is occasionally up to 10 or 12 cm. called the sinus mite, is a parasite of the in length. upper respiratory system of the dog first Life Cycle described and named by Chandler and Ruhe4 in 1940. Their specimens were taken The eggs are deposited by the female from a Boston terrier from East Lansing, and pass out in mucus when the dog Michigan. Although mites have been re­ sneezes, or they are swallowed and pass ported from the upper respiratory tracts out in the feces. A suitable host animal of seals, old world primates and a South eats contaminated vegetation and thereby American monkey, this was the first re­ ingests the eggs. The eggs hatch in the port of them in dogs. Since then Martin alimentary canal of the host animal and and Deubler5 have reported finding the the larvae~make their way, as a rule, to same species of mite from three dogs in the liver, lungs, and lymph nodes, espe­ the area of Philadelphia. cially the mesenteric lymph nodes, where The first was from a middle-aged fox­ they develop into the infective nymphal hound whose death was caused by an stage. This stage resembles the adult but acute meningo-encephalitis resulting from is only 5 or 6 mm. long, is white in color, injury over the right eye. On examining and has four legs. It lies in a small cyst the brain cavity they noted small, cream­ and is surrounded by viscid, turbid fluid. colored, eight-legged moving According to Monnig1 the nymph may about in the frontal sinuses. Further ex­ leave the cyst and wander in the body of amination revealed their presence on the the intermediate host, and in this way it mucous membrane covering the turbi­ is believed that infection of herbivores nates and other structures forming the with adults occurs. Dogs become infected nasal passages. Large numbers of mites by eating rabbits or glands of larger were found but the heaviest concentration herbivorous animals which contain the was in the frontal sinuses. The mucosa encysted nymps. The nymphs wander showed slight redness but could not be through the body of the dog and attach considered to be greatly altered. themselves high in the nasal cavity where they mature. In the South the nymphs are Second Case quite common in cattle while in Europe, About a month later a second case was sheep are said to be the most common noted in a golden retriever with a history intermediate host. Rabbits and other of never having previously been sick. Just herbivorous animals also act as interme­ prior to its death the animal greeted its diate hosts. owner, ran back and forth in the house As has been stated, the parasites attach several times, and then laid down and sud­ high up in the nasal passages. This pro­ denly died. The head and sinuses were duces severe irritation and causes the dog examined and the nasal passages were to sneeze and cough at intervals. Often found to be heavily infected with arthro-

168 The Veterinary Student pods similar to those found in the fox­ 0.6 mm. They are pale yellow or cream hound. Many mites were found partially colored. Most specimens contained a large imbedded in the nasal mucous membrane egg in the abdomen, some of which showed down to and beyond the points of the tur­ a well-developed embryo. binates. About one hundred mites were No definite symptoms are known but found, some of which were six-legged the symptoms that should probably cause larvae. Again there was not much change one to be suspicious of infection with this in the affected tissues. mite are sneezing, head shaking, rubbing The third case was observed about five the nose, and mild nervous reactions. The months later in a six-year-old terrier. It mite probably occurs more often than was was presented to a clinician because it formerly thought but is not frequently re­ suddenly seemed to lose control of its ported because the sinuses and nasal cav­ front legs and fall to the ground, at which ity are not routinely examined during post time it began to move its head from side mortem examination. to side as though trying to dislodge some­ Esophageal Worm thing from it. These symptoms lasted about thirty seconds. The dog then arose Spirocera lupi, a nematode parasite of but seemed to lack coordination of its dogs and other , is sometimes re­ movements and appeared slightly nervous. ferred to as the esophageal worm. It is a About five minutes later a similar attack parasite of the esophagus, stomach, and occurred. From that time on when the sometimes of the aorta, is blood-red in animal moved about or became excited it color, and is usually coiled. The male is would develop convulsive or preconvul­ 3 to 5 cm. long and the female is 6 to 8 sive symptoms. There seemed to be loss cm. in length and 1 to 1.5 mm. wide. The of appetite and at times the animal was eggs are 30 to 35 microns long by 10 to 15 unable to locate its food. The dog became microns wide, thick shelled, and contain progressively worse, becoming nervous an embryo when deposited. The eggs, and showing symptoms of fright. The ap­ when deposited by the female, pass ()ut ih petite and incoordination also became the feces and are consumed by coprbpha­ worse and the dog was destroyed eight gus beetles which act as the interrriediate days after first symptoms appeared. The hosts. The larvae pass from the digestive owner reported that the dog had always tract to the body cavity of the beetles, been nervous and about a year before be­ encyst, and develop to the infective stage gan to snap at imaginary objects. in about two months. When the beetles are eaten by dogs the larvae are set free Mites In Sinuses and go to the site of infection where they A moderate number of mites were penetrate the tissue and develop into sex­ found in the frontal sinuses and nasal pas­ ually mature worms. The usual location sages. There seemed to be little macro­ is the thoracic portion of the esophagus, scopic change in the sinus and nasal mu­ but occasionally they are found in the cous membranes. Martin and Deubler stomach or aorta. They cause a prolifera­ reported that all the mites were found to tion of connective tissue forming growths be pubescent and gravid females. This which vary from about 2 to 4 cm. or more may mean that the males are very small in diameter and, when in the esophagus, or quite rare or that the mites reproduce have openings into its lumen. parthenogenetically. The latter seems im­ Pressure from large growths may cause probable in that all writers describing either coughing, dyspnea, or interfere with species of a closely related genus describe circulation. Rupture may be followed by males. pleuritis. A growth on the aorta may re­ The general shape of the mite is oval sult in aneurysm and possible rupture. with the posterior part slightly broader The symptoms are not constant because than the anterior part. The average body growths in the esophagus may cause sten­ length is slightly over 1 mm. and the osis, perforation, dysphagia, vomition, loss width at the widest point is slightly over (Continued on page 204)

Spring, 1943 169 PARASITES OF nOG with six hooks and the body is approxi­ (Continued from page 169) mately 0.6 mm. in length. The copepod is eaten by a suitable fish of weight, and pleuritis. Growths in the and digested. This sets the procercoid' circulatory system may cause angina, free. It loses its cercomer and hooks, dyspnea, suffocation, syncope, and hemor­ passes through the stomach wall, enters rhage. the body cavity, makes its way to the mus­ The prognosis is unfavorable and the culature, liver, or other organs, and de­ treatment only symptomatic or prophylac­ velops into the so-called plerocercoid. This tic because of the lesions produced. The stage is 1 to 2 cm. long and worm-like in parasites have beE!n reported from many appearance. It coils up and waits for some of the states, but are found mainly in the to consume the fish and liberate Southeast. it. When this happens it attaches itself to the mucosa of the intestine and develops Broad Fish Tapeworm into a mature tapeworm in three or four DiphyUobothriumlatum, the broad fish weeks. Only certain fish act as hosts for tapeworm, is seldom mentioned in veter­ the parasite at this stage. In 1927, wall­ inary literature and its too often consid­ eyed pike, northern pike, and perch taken ered as just another tapeworm of the dog from Shagawa Lake at Ely were one hun­ when in reality it is quite different from dred percent infected with plerocercoids other species. It has the most interesting to a greater or less extent. Such fish as and probably the most complex life cycle crappies, suckers, and mongrel whitefish of this group and is a parasite in man as which also inhabit the lake have at no well as in dogs. Before 1927 it was thought time been shown to harbor the larvae. to come from eating fresh-water fish of The adult worm in man may obtain a European origin and it was assumed that length of 8 to 10 meters and contain three the life cycle was not carried out in or four thousand segments. The segments America. However, during 1927 Ward, have a maximum width of about 15 mm. Essex, and Magath7• 1o, working at Ely, and are wider than they are long. The Minnesota, proved that the parasite oc­ head is very small and, different than that curred in American waters. In 1928 Ver­ of ordinary tapeworms, has no hooks and geerll minimized man as the spread.er and only two slit-like suckers with which to at­ blamed the dog to a greater extent. tach itself to the intestine of the host. A The ova are egg-shaped, yellowish­ feature that easily separates this parasite brown in color, and have an operculum from other tapeworms is the brown spot at one end. This is the only species of in the center of each segment which gives tapeworm of domestic animals whose ova a beaded appearance throughout the do not have six hooklets at the time they length of the worm. This spot consists of pass from the host. An ovum will develop the uterus and ova. As the worm grows, in a few weeks in the water depending the posterior segments break off, ruptur­ on the temperature, and the small ciliated ing the ovaries and discharging ova into larva, the coracidium, escapes through the intestinal contents of the host. The the operculum. The coracidium swims host then must deposit the feces in the around in the water and soon dies unless water or· on very moist soil and thus the ingested by a . Of the crus­ cycle is repeated. taceans, only certain copepods are suit­ able hosts. Among these are Cyclops Tapewonn Dwarfed strenuus, Cyclops prasinus, and Diap­ When this tapeworm is found in dogs, tomus gracilis. The coracidium penetrates it is dwarfed both in length and width as the wall of the digestive tract of the cope­ compared to that found in a human host. pod and develops into the procercoid in Essex10 found ova from dogs to be less the body cavity in two or three weeks. than ten percent hatchable while ova from It is this stage that has the globular ap­ human feces were nearly one hundred pendix or cercomer which is provided percent hatchable. These observations

204 The Veterinary Student lead one to believe that man is the pre­ weeks and if found the animal should be ferred or true host of the worm in spite retreated. of the fact that the dog and wild carni­ Lentz recommends feeding lean meat vores are thought to be most important in the night before and milk about two hours spreading it, and that in certain areas it is prior to treating in order to form a soft reported to be the most common tape­ curd in the intestinal tract and prevent worm of the dog. excessive cramping. This is followed with Dogs are seldom fed raw fish. In fact, one-eighth to one-half grains of arecoline most dogs will refuse to eat it. However, hydro bromide orally depending on the once they develop the taste for it, they size of the dog. The animals are not fed often show a preference for it. It is often for several hours after treatment. reported that dogs, having acquired a taste Control of the parasites involves man for raw fish, will refuse a meal only to be as well as dogs. Defecation along river found at a garbage heap shortly afterward and lake banks should be avoided as ova consuming fish scraps. These dogs are fre­ are easily washed into them by rain. All quently reinfected with the tapeworms. fish used for food for man and dogs should be well cooked. Symptoms Ancylostoma braziliense is a hookworm found in dogs, , and a great many Little clinical disturbance is caused by other carnivorous animals distributed infection with this parasite. However, in over a large part of the earth, especially young dogs in particular, Thompson" has in tropical and subtropical countries. It noticed decided evidence of malnutrition is very similar in appearance and life cycle accompanied by a ravenous appetite. to the common dog hookworm, Ancylos­ Marked anemia has been reported which toma caninum, but slightly smaller and Cameron12 says is due to hemolysins liber­ more slender, the male being approxi­ ated by the parasite. He also states that mtaely 7.5 mm. long and the female ap­ tapeworms are heavy calcium consumers proximately 10 mm. It is differentiated and that they take their nourishment by from A. caninum by microscopic examina­ osmosis from food within the intestinal tion of the buccal capsule. A. braziliense tract. D. latum is said to be the only tape­ has a large triangular tooth on each side worm with which anemia is associated. of the oral opening dorsally and a smaller The above listed symptoms rapidly dis­ tooth on each side ventrally. A. caninum appear on removal of the parasites. Old has a buccal capsule armed with three dogs seldom show serious symptoms. The strong teeth on each side. segments are often seen hanging from the anus and often it is this that attracts the Life Cycle owner's attention and prompts him to re­ The adult female A. braziliense deposits quest that the dog be treated. ova in the small intestine of the host. The treatment for this parasitism is the These ova pass out with the feces and un­ same as for infection with any species of der favorable conditions of warmth and tapeworm. Thompson(l recommends starv­ moisture hatch and produce small larvae. ing for one or two meals followed by a The larvae moult twice and then become dose of arecoline hydrobromide. He first infective. Under ordinary conditions they used one-quarter to one-half grain but Enter the body of a suitable host either by later cut it to one-tenth grain and claimed ingestion or by penetration of the skin. better results. Severe peristaltic contrac­ When they penetrate the skin of the dog tion may cause the segments to break from or they leave no noticeable lesion. the scolex so that they are passed and the They eventually make their way to the latter retained. If this happens the seg­ intestine where they mature. However, ments are regenerated in a short time. if they come in contact with human skin, This may explain the better results from they produce a condition of special inter­ the reduced dosage of arecoline. The feces est. It is for this reason that the parasite should be checked for ova in about six is mentioned here.

Spring, 1943 205 When the infective larvae come in con­ REFERENCES tact with human skin, they penetrate it 1. Monnig, H. O. Veterinary Helminthology and Entomology. 2nd ed. Wm. Wood & Co. Baltimore. and produce a condition known as creep­ 1938. ing eruption. This lesion is characterized 2. Price, E. W. Some of the rarer and more neglected parasites of dogs and cats. Jour. Amer. Vet. by linear, tortuous, and serpiginous erup­ Med. Assn. 74 (n.s. 27) :864-878. 1929. tions, accompanied by intense itching. It 3. Meador, D. J. Tongueworm of the dog. Jour. Amer. Vet. Med. Assn. 70(n.s. 23) :525-526. is not fatal but causes much distress to 1927. the patient. When the larva enters the 4. Chandler, W. L., and Ruhe, D. S. Pneumonyssus skin it produces a stinging sensation which caninum N. sp., A mite from the frontal sinus of soon passes away. It may remain at the the dog. Jour. Parasitology. 26:59-70. 1940. 5. Martin, H. M., and Deubler, M. J. (Pneu­ point of ingress for a while, producing an monyssus sp.) of the upper respiratory tract of itchy, erythematous, urticaria-like, papu­ the dog. University of Penn. Vet. Ext. Quart. lar lesion which resembles a 89. 43 (9). 1943. 6. Thompson, J. E. Some observations on the Eur­ bite or the effect of a chigger. Then a lin­ opean broad fish tapeworm Diphyllobothrium ear lesion extends from it along which latum. Jour. Amer. Vet. Med. Assn. 89 (n.s. 42) 71-86. 1936. vesicles may form, and it may become sec­ 7. Magath, T. B. The relation of Diphyllobothrium ondarily infected. These lesions may exist latum infestation to the public health. Jour. and continue to progress for a few days Amer. Med. Assn. 101 :337-341. 1933. 8. Hall, M. C., and Wigdor, M. A bothriocephalid to six or eight months or more if not tapeworm from the dog in North America with properly treated. Sensible perspiration is notes on cestode parasites of dogs. Jour. Amer. necessary for the larvae to penetrate the Vet. Med. Assn. 53(n.s. 6) :355-362. 1918. 9. Van Es, L., and Schalk, A. F. Notes on parasitic human skin. Thus creeping eruption oc­ anaphylaxis and allergy. No, Dak. Agr. Exp. curs during warm weather, especially if Sta. Bu!. 125: 151-193. 1917. it is humid. Experiments have shown to. Essex, H. E. Early development of Diphylloboth­ rium latum in Northern Minnesota. Jour. Para­ that thermotropism is more of a factor in sitology. 14:106-109. 1927. penetration of the skin than is histio­ 11. Vergeer, T. Diphyllobothrium latum (linn. 1758) tropism, and the larvae have been shown the broad fish tapeworm of man. Jour. Amer. Med. Assn. 90:673-678. 1928. to pass through moist clothing. 12. Cameron, T. W. M. Immunity against animal para­ sites. Proc. 12th Intern. Vet, Congo 1934. 111 :44-65. Development of Larvae 1935. Warmth and moisture favor the devel­ 13. Hall, M. C. Therapeutics of worm diseases. Proc. opment of the larvae in the soil and tend 12th Intern. Vet. Congo 1934. 111 :1-19. 1935. 14. Kirby-Smith. J. L., Dove, W. E., and White, G. F. to increase the parasitism in dogs and Some observations on creeping eruption. Amer. cats. The increased incidence in animals Jour. Trap. Med. 9(3) :179-193. 1929. further increases the contamination of soil 15. Dove, W. E. Further stUdies of Ancylostoma bra­ ziliense and the etiology of creeping eruption. and the infection of man. The infective Amer. Jour. Hygiene. 15 (3) :664-711. 1932. larvae remain alive for long periods of time under favorable conditions. Accord­ ing to Dove15, they have remained infec­ tive under laboratory conditions for one PYRETHRUM SUBSTITUTE hundred and eighteen days. Rain and Powdered sabadilla has now been pro­ other type of surface water may spread cessed so that it can be used as a spray. If the parasites over a considerable area, but this form is as effective as the powdered drying destroys both eggs and larvae. form, which is the indication of the pre­ Infection with Ancylostoma braziliense liminary tests, it may replace the limited in dogs is treated the same as that for supply of pyrethrum remaining in this Ancylostoma caninum. Among the anthel­ country. The development of the spray is mintics recommended are tetrachlorethy­ the work of T. C. Allen and Robert Dicke lene, 0.3 cc. per kilogram body weight; or of the Agricultural staff of the University N-Butyl chloride, 1 cc. per kilogram. of Wisconsin. pyrethrum is a Japanese (The author is indebted to Dr. E. A. product. The substitute, sabadilla, is im­ Benbrook of the Veterinary Pathology De­ ported from Central and South America, partment, Iowa State College, for his as­ chiefly from Mexico and Venezuela. sistance in preparing this paper.) -Science News Letter

206 The Veterinary Student