SPIROCHBTA POLLACHII: A NEW BLOOD-IN- HABITING SPIROCHBTE FROM GADC-S POLLACIIICS,

THE POLLACK; WITH A NOTE ON THE OCCURRENCE OF CERTAIN INTRACORPUSCULAR BODIES IN THE BLOOD OF THE GADIDB.’

By HERBERT HENRY, M.D., B.S.(Lond.), Demonstyator of Pathology in the University of Sh&ld ; Assistant Physician to the Shqjield Royal Hospital.

From the Palliologieal Laborahy of the University of Sheflcld.

(PLATE XIX.)

THE occurrence of the spirochzete which is the subject of the present communication was first reported by me (January 1 9 1 0 ’). Out of 348 fish taken from Port Erin Bay in September 1909, oiily two were found to harbour spirochaAes in their blood, both these fiRh being speci- mens of Gaduspollachius. Thirty-three further examples of this fish were carefully examined but with negative result. The other members of the Gadidce examined included numerous specimens of Gadics wtorrhwa, Gadus virens, Gadus luscus and Gadzu nierlangus, but here too the search for spirochztes proved fruitless. Since then I have esnniiued the blood of eyer 800 more seafish, but have failed to find any further cases of spirochztal infection.

The infected fish mere adult Rpecimens taken by means of a trammel net laid in inshore water at a depth of four to six fathoms. Films were prepared with blood taken directly from the heart. These, after being allowed to dry in air, were fixed imniediately for twenty minutes in nbsolute methyl alcohol, and were stained some two weeks afterwards, on returning t o the laboratory. Uiifortunately there was no opportunity of examining fresh blood, or of making wet fixed films, and the description of the parasite is confined only to ib appearance in films prepared as above mentioned. The best preparations were obtained by staining for twenty-four hours in weak solutions of Giemsa, Leish- man’s stain or Unna’s polychrome methylene-blue.

In thc bloocl of the first infected pollack there is a spirochzte in every six or eight oil-immersion fields, whereas in the second, ten or fifteen minutes search is necessary to find a single parasite.

Received June 24, 1912.

SPIROCHATA POLLACHIL 161

For descriptive purposes the parasites may be divided into short forms, long forms and dividing forms.

SHORT FORMS.

These make up about 5 0 per cent. of the total number of spirochaetes present. They vary from 8 p to 1 3 p in length, the average leugth being 11.5 p. They are usually quite straight (Plate XIX. Figs. 1-4) and show less deeply staining pointed extremities, though some are slightly curved or sickle-shaped (Figs. 7-10). The number of spiral8 present in each individual varies, being in most examples relatively great, but occasionally they are fewer (Fig. 5), so that the parasite has a drawn-out appearance. The average number of spirals in a series of carefully measured examples of this short form is 7.7, so that each spiral is about 1.5 p in length.

LONG FORMS. These differ from the smaller forms only in their greater length,

which varies from 15 p to 20 p, the average lying between 17 p and 18 p. Here the spirals average 10.4 in number, each being 1.6 p in length, so that for increase in length the larger forms show a propor- tionate increase in the number of spirals. These large forms make up 38 per cent. of the total number.

DIVIDING FORMS.

Some of the large individuals show in their centre a tbinned-out portion where the undulations are either shallow or entirely absent, an appearance strongly suggestive of transverse division. Such division results in the production of two spirochaetes, which not infrequently lie in actual continuity and are identical in size with the short forms (Figs. 25-28). It is also common to find two spirochaetea lying within a short distance of each other in the same microscopic field, the separation having resulted probably from the mechanical spreading of the blood film, or having occurred during the drying process previous to fixation.

I n several specimens of blood taken from examples of Gadus pollachius, Gadus Uirens, and Gadus morrhua, there have been found cer- tain corpuscular inclusions, which may represent encysted phases of a spirochaete. Most commonly these occur as small circular bodies, 0.5 p to 2 p in diameter, situated between the nucleus and the periphery of the corpuscular protoplasm, and taking on a solid purple staining like the chromatin of the nucleus. Usually only one such body is found in each corpuscle (Figs. 29, 30), but at times two are met with, situated close together or lying on opposite sides of the nucleus (Figs.

162 HERBERT NENR Y:

31-34). In one instance two such closely apposed bodies were found connected by a strand, thus presenting a dumb-bell appearance (Fig. 3 2). A larger swollen form of intracorpuscular body which appears as a diffusely staining blue spherical mass (Fig. 3 5) is occasionally seen. Such an inclusion may show round its periphery a ring of purple- staining material of varying thickness (Figs. 36, 37), or this material may be aggregated at various points as a series of minute deeply staining dots (Fig. 38). At times it is clumped on one side so as to give a semilunar outline (Fig. 39), and occasionally a crescentic body only is found, the rest of the small sphere having disappeared or being unstainable (Fig. 40). Stout rod-like bodies are occasionally found lying in close proximity to, or in actual continuity with, intracorpuscular bodies (Figs. 41, 42), and there is depicted an appearance suggesting the emergence of a fully 0edged spirochste from a crescent which still remains as a blue .structure with none of the purple staining (Fig. 43).

Until comparatively recently spirochzetes had not been described as existing in the blood of seafish, the credit of their discovery being due to Neumann (1909 2). Out of 614 fish taken from the Gulf of Naples, this observer found only two which showed spirochztal infection, one a specimen of Gadus nainutus, the other a specimen of Pelamys sarda. My own experience would show the condition to be still less frequent in fish taken from British waters, only two infected fish being found in a series of about 1 2 0 0 specimens examined.

The spirochste found in Gadus minutus, and named by Neumann Spirochmta qadi, presents considerable resem blance to Spirochceta gallinarum. It varies from 5 p to 22 p in length, the majority of examples falling between 1 0 p and 16 p. The spirals are few in number and measure 3.5 p to 4 p in length, with an average breadth of 1 p. On the other hand, SpiTochmta pelandis is shorter, being 9 p to 1 0 p in length, with double forms 18 p to 20 p long, and shows a greater number of spirals, these latter being 1 p to 1.5 p long. The spirochate which I have described, and for which I would suggest the name Spirochccta pollachii, is obviously quite distinct from Neumann’s 8pirochceta qadi, but exhibits several points of resemblance to Spirochcetn pelanaidis. There are many difficulties in the way of a true interpretation of the significance of the intracorpuscular bodies I have described. For instance, I have found that in the process of making air-dried films the red corpuscles of the Gadidce suffer more than those of any other group, with the exception of the red corpuscles of Scylliuna and Raia. Where the atmosphere is heavily laden with moisture, as occurs in a marine aquarium or in an open boat during dull and rainy weather, the process of drying is much retarded, and the red corpuscles of the Gadidce show rapid crystallisation of the hemoglobin, a feature which distinguishes them from the corpuscles of all other groups oE fish I have yet examined. This change pro- duces not only distortion in the shape of the corpuscle, but a t times

SPIROCHBTA POLLACHI% 163

tends to fragment the nucleus so that small pieces of chromatin lie free in the cell protoplasm. I have been careful, therefore, in the examination for the intracorpuscular bodies, to use only such slides as show no sign of corpuscular degeneration.

Again, some of the intracorpuscular bodies (Figs. 29-34) reeemble closely the so-called polar granules which occur in the physiological degeneration of certain vertebrate corpuscles, most notably those of Axolotl, and which are to be looked upon as nuclear extrusions. A similar appearance is produced if the red corpuscles of fresh-water or salt-water fish are left to degenerate in the presence of a trace of Unna’s polychrome methylene-blue. Moreover, I have in my possession a series of air-dried films taken from a specimen of Solea vulgaris and showing (L very heavy infection with Hmmogregarina Simondi, in which the occurrence of twin polar granules (as in Fig. 31) is very frequent, but I have never found a spirochaetal infection in Solea.

On the other hand, certain of the blood-inhabiting spirochaetes have been shown very definitely to present encysted phases in their life-history. Such phases have been fully described and figured, for example, by Balfour in the case of the spirochaetosis of Sudanese fowls (1908 In the so-called after-phase of this disease the spirochztes, as siich, disappear from the blood, but there are found in the circula- tion large numbers of red corpuscles containing bodies of various shapes and sizes which undoubtedly represent encysted phases of Spirochmta gallinnrunt. An examination of Balfour’s figures shows that there exists a close resemblance, in outline if not in size, between many of the intracorpuscular phases of the fowl spirochaete and the bodies herein described, and therefore it is perhaps not too much to assume that some at least of these latter bodies represent phases of Spirochmta pollnchii. The material a t my disposal, however, shows the fish infection to be so slight as compared with that which obtains in chicken spirochatosis, and the intracorpuscular bodies to be so scanty, for they are found only after prolonged search, that it is difficult to speak with certainty on the point.

On none of the specimens of pollack examined were ectoparasites found, so that it is impomible as yet to suggest a carrier of the infec- tion from fish to fish.

REFERENCES.

1. HENRY . . . . . . . “On the Hamoprotozoa of British Seafish,” Journ. Path. and Bacteriol., Cambridge, 1910, vol. xiv. p. 463.

2. NhmlANA . . . . . . “ Studien iiber protoeoische Parasiten im Blut von Meeresfischen,” Ztschr. f. Hyg. u. Infectionskrankh., Leipzig, 1909, Bd. xiv. Heft 1, 5. 1.

164 SPIROCHXTA4 POLLACHIL

3. BALFOUR . . . . . . r c Spirochsetosis of Sudanese Fowls," !l"u'i*d Report, Wellcome Research Laboratm'e8, Gordon Memorial College, Khartoum, 1908.

DESCRIPTION OF PLATE XIX.

(Drawn with Zeiss camera lueida. Magnification, 1500 diameters. Giemsa stain.)

Frcs. FIGS. 14-22.-Long forms. FIGS. 23,24.-Abnormal groupings. FIGS. 25-28.-Dividing forms. FIGS. 29-43.-Intl.acorpuseular bodies (described in text).

show in the films.)

1-13.-Short forms of SpirochcEta pollachii.

(The spirochietes are drawn with greater diameter and with deeper staining than they

JOURNAL OF PATHOLOGY.-Vot. XVII PLATE XVIII.