I . PHOTOZO~L., 2, 19-20 (1955)

Entamoeba bubalus, n.sp., from Carabao

19

GLENN A. NOBLE Califurnia Sfnte Polytechnic College, Sun Luis Obispo, California

~- c__ .

SUMMARY. 'lwel\e carabao in the Philippines were found to be lightly infected with intestinal amoebae. Trophic forms ( 1 2 microns in diameter) of this protozoan possessed a definite ectoplasm and a homogeneous endoplasm. They were found only in stained preparations. The nucleus was similar to that of the cyst. All unconcentratcd fecal smears contained at least a few cysts (8 microns in diameter). In these forms the cytoplasm usually contained a large vacuole and one or more irregular chromatoidal bodies. The nucleus (2.6 microns in diameter) possessed a pronounced, deeply staining, uniform peripheral ring and a large irregular endosome. There was no periendosomal ring, This amoeba is designated as E77lnnto~bn bzlbnllc.r, 11.s~ .

U R I h G THE academic year 1953-1954 the author had an opportunity, as a Lecturer at the Univer-

sity of the Philippines under the Fulbright program, to continue a study of intestinal amoebae of domestic mammals Almost all of the large animals examined, as in other countries(3). contained amoebic cysts. This report is limited to the results of a study of fifteen water buffalo, or carabao ( B u b u b s bubulis) from sev- eral islands of the Philippine group. Twelve of these animals were infected with amoebae.

the cytoplasm. The large endosome, 2 microns in diameter, was characteristic. This structure seemed to lie a group of several closely adjacent granules.

Twenty-three cysts (Figs. 2 and 3 ) were found. 'Their average diameter was 3 microns (range 5-9). All of th,em contained one or more vacuoles. Usually there was a single large vacuole which crowded all cell contents to the periphery. The cytoplasm was made up of fine granules. Chromatoidal bodies were present

MATERIALS A N D P1ETHOL)S

Fecal material was esamined a5 fresh as possible with saline and with iodine dilurnts. Samples were taken at random from the inass. Heidenhain's iron hematoxylin. using 2% phosphotungstic acid for destaining. was employed in making permanent slides. Outlines of the protozoa and their organelles were drawn with the aid of a camera lucida and were used as the basis for illus- trations. Measurements were taken with an ocular micrometer which was calibrated against a standard stagt micrometer for each magnification used.

RESliLTS

.-\lthuu~h most of the carabao harbored amoebae. infection was light in every infected animal. Kumbers of cysts per entire slide ranged from 0 to 6. I-sually there was only one or two. The blood of one of the host animals was infected with TQJ~UITOSO?PZO ~ v a n s i and several others harbored a species of intestinal trichomonad. All carabao were afflicted with intes- tinal worms.

They Only two motile forms (Fig. 1) were seen.

20 Entamoeba bubalus

in all cysts. Th,ese bodies were occasionally large with rounded ends s i rnihr to those of Entnriic~cbu histol?tic-o (Fig. 2 ) , but more often were small and irregular in size and shape (Fig. 3 ) . The nucleus averaqetl 2.6 microns (range 1.2 - 3.3) in diameter and was. in gen- eral, similar in appearance to that of the motile form. A distinct peripheral ring was usually seen. Chromatin distribution in the nuclear wall. however. varied. In some organisms there was practically none. in others there appeared a ring of dots. in still others there were a few isolated larger clumps. The endosome averaged 1.4 microns (range 0.8 - 1.6) in diameter. Often this structure appeared to b,e a cluster of four cranule.. There was no periendosomal ring.

DISCUSSION W D GENER.\L C’OYCLUSIONS

Earlier work on the genus Enturriocbn in domestic mammals threw doubt on the validity of assigning dif- ferent species names to thesc intestinal amoebae. ,L\ recent study of the amoebae of Philippine goats( 2 ) . however. indicated a new species from this host. In the

carabao the amoebae are likewise distinctive enough to be called a different species. The nucleus. especially. has constant diagnostic characteristics. Its heavy. usually uniform, outer ring and large prominent endo- some serve to distinguish this species. Compared to any random selection of twenty-three amoebic cysts from other domestic mammals. those from carabao showed remarkably little variation in structure. The distinctiveness of this amoeba and its apparent limita- tion to the carabao warrants its designation as Elztn- rnochn hirhnlus, n.sp. Cross-infection experiments. however. should be carried on. As Chen ( 1 ) and others have emphasized. host specificity is one of the best means of identifying species of all types of paraTites.

REFERENCES

1. Chtm. T. H . (1940). Morphological and developmental .tudirs (11 Paragonimus iloktsuensis with some remarks on other specie5 o i the genus (Trematodn : Troglotrematidae) . Lingnnn Sri. .I., 19. 4?9-5.10.

2 . Koble, G. .4., (19.54). Eiztaiiroeba dilinzani, n s p from Philippine goats. Philippine J . Sci., (in press).

3 . Soble, G . -4. & Noble, E. R. ( 1 9 5 2 ) . Entamoebae from i:lrm mamm;rl.-. .I. Pnrn.pitol.. 38. 571-.5q5.