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Ciliary structures in the microfilaria of Loa Loa
290
CORRESPONDENCE
None of the patients had significant anaemia or leucocytosis before or during treatment. Tests for heterophil antibodies were negative on patients No. 2 and 4, three weeks and one week after onset of symptoms respectively. As far as we could ascertain, no parasitic diseases besides toxoplasmosis have been associated with increased counts of atypical lymphocytes. Our finding that elevated numbers of atypical lymphocytes were present in about one half of the patients with malaria was similar to the observations of others on patients with toxoplasmosis. Atypical lymphocytes were noted in only 5 of the 10 cases in one study (SIIM, 1956) and 6 of the 30 in another series (BEVERLEY, 1958) of patients with toxoplasmosis. In contrast to many patients with toxoplasmosis who had symptoms similar to “glandular fever” the malaria patients with moderately elevated atypical lymphocyte counts did not exhibit such physical signs. Their lymph nodes and spleens were not enlarged. An increased number of atypical lymphocytes has usually been associated with infectious mononucleosis, some viraemias, and other diseases. In a review article (WOOD, 1967) malaria and quinine were listed as “doubtful or poorly documented causes of atypical lymphocytosis” but no references were provided. We therefore present our findings on the patients with malaria. We are, etc., R. D. PARGLE,* c.
LADD.
*Assistant Chief, Department of Pathology, USPHS Hospital, Staten Island, New York, U.S.A. 17 February,
1969 Current Address : (Dr. Paegle) Department of Pathology, Brooklyn-Cumberland Medical Center, Brooklyn, New York, 11201.
121 DeKalb
Avenue,
REFERENCES
J. W., Critique-Hematology “Check Sample” No. H-26, American Clinical Pathologists, Commission on Continuing Education, Council tology, N.P. 1966. DOWNEY, H., MCKINLAY, C. A. (1923). Arch. intern. Med., 32, 82. WOOD, A. T., FRENKEL, E. P. (1967). Am. J. Med., 42,923. ROBBINS, M. (1959). Am. J. Med. Techn., 25, 87. SIIM, J. CHR. (1956). Arm. N.Y. Ad. Sci., 64, 185. BEVERLEY, J. K. A., BEATTIE, C. P. (1958). Lancet, 2, 379. REBUCK,
CILIARY
STRUCTURES
IN
THE
MICROFILARIA
Society of on Hema-
OF LOALOA
S&-Recently KOZEK (1968) reported unusual “cilia” in the microfilaria of Dirojilaria immitis, which differed from normal kineto-cilia in that they did not show the usual pattern of 9 + 2 microtubules. The “cilia” were located within paired channels in the cephalic Each cephalic channel contained a maximum of 9 and caudal regions of the microfilaria. “cilia” at its base, although only 3-5 of these reached the channel orifice. The caudal channels were shorter, and each contained only one “cilium”. In this laboratory I have found these “cilia” also in the microfilariae of Loa loa, In the region of the nerve ring there recovered from the blood of Mandrillus leucophaeus. are several dendritic processes which extend forward into the posterior part of the cephalic which become organized to show space. These processes contain numerous microtubules, a “g-fold” symmetry; each process then resembles a “cilium”. Two channels, resembling those described by Kozek, originate in the posterior part of the cephalic space, and open near the anterior tip of the microfilaria. Each channel has a maximum diameter of 1.3 p taper to about 0 -25 p in at its base, and encloses up to 9 “cilia” (Fig. 1). The ChaMelS diameter near the anterior end of the microfilaria, but their apertures differ in appearance.
CORRESPONDENCE
(ToFacePage290)
291
CORRESPONDENCE
One aperture lies near the anterior tip of the microfilaria, but only one of the nine “cilia” reaches its orifice. The other channel turns obliquely before reaching the tip, and 3 “cilia” reach its orifice (Figs; 2 and 3). The aperture of each cephalic channel is filled with a plug of dense material, and the anterior tips of the “cilia” lie in close apposition to these plugs (Fig. 3). The cephalic “cilia” measure approximately 0 ~2 p in diameter at their point of origin within the channels, but distally they are slightly smaller. The “cilia” are surrounded by a layer of dense material (Figs. 2 and 3). The “9-fold” symmetry is lost in the distal ends of the “cilia”, and the microtubules show a wide variation in both number and arrangement. In addition to those “cilia” which are enclosed within the ceuhalic channels. I have observed other “cilia” within the cephalic space. There appear & be 8 of these “cilia” (Fig. 2), and I have never found them to be enclosed within channels. They extend to the anterior tip of the microfilaria, where they probably terminate in the cephalic papillae (Fig, 4). The number and arrangement of the microtubules vary along the length of these eight “cilia”. A central channel is seen in transverse sections through the anterior part of the microfilaria (Fig. 2), and this probably corresponds to the pharyngeal thread described by LAURENCEand SIMPSON(1968), from light microscopy. At the posterior end of the microfilaria there are 2 caudal ciliary channels, which measure approximately 0.3 p in diameter; each contains only one “cilium“ (Fig. 5). The caudal “cilia” measure annroximatelv 0.25 u in diameter. and distallv thev are invested with a thick coat of den;; material. * The orifice of each channel is fiiled with a plug of dense material which is similar to that seen in the cephalic channels. The function of these unusual “cilia” is not yet clear. Kozek suggested that in Dirofilurz’u immitis thev mieht be sensorv structures associated with the develonine am&ids and phasmids. The bcc&ence of cephalic papillae in the microfllaria of Loa lo; indicates that at least some of the characteristics of the adult worm may be recognized in the prejuvenile stage. Therefore it seems likely that the cephalic and caudal ciliary channels are indeed the precursors of the amphids and phasmids. According to the general account of periodicity set out by HAWKING(1967), microfilariae should be sensitive to minute differences in oxygen tension at both their anterior and posterior ends. If the cephalic and caudal ciliary channels are sensory organelles, it seems possible that their function might be to detect such changes in the environment. I am, etc., DIANE J. MCLAREN. Division of Parasitology, National Institute for Medical Research, Mill Hill, London, N.W.7. 20 February, 1969. REFERENCES
F. (1967). Proc. Roy. Sot. B., 169, 59. KOZEK,W. J. (1968). J. Purasit., 54, 838. LAURENCE, B. R. & SIMPSON, M. F. (1968). J. Helminth., HAWKING,
FIG. FIG. FIG. FIG. FIG.
42, 309.
1. Transverse section near the base of one cephalic ciliary channel. x 57,000. 2. Transverse section near the anterior tip of the microfilaria. x 33,000. 3. Longitudinal section to show the apertures of the cephalic ciliary channels. x 42,000. 4. Section through the anterior tip of the microfilaria, showing one of the cephalic papillae, and the aperture of one cephalic ciliary channel. X 50,000. 5. Transverse section through the posterior region of the microfilaria, to show the two caudal ciliary channels. x 40,000. KEY TO
C-cilium CA-caudal ciliary channel GE-cephalic ciliary channel CP-cephalic papilla
LETTERING
OF FIGURES
M-muscle P-plug PT-pharyngeal S-sheath.
thread
CORRESPONDENCE
None of the patients had significant anaemia or leucocytosis before or during treatment. Tests for heterophil antibodies were negative on patients No. 2 and 4, three weeks and one week after onset of symptoms respectively. As far as we could ascertain, no parasitic diseases besides toxoplasmosis have been associated with increased counts of atypical lymphocytes. Our finding that elevated numbers of atypical lymphocytes were present in about one half of the patients with malaria was similar to the observations of others on patients with toxoplasmosis. Atypical lymphocytes were noted in only 5 of the 10 cases in one study (SIIM, 1956) and 6 of the 30 in another series (BEVERLEY, 1958) of patients with toxoplasmosis. In contrast to many patients with toxoplasmosis who had symptoms similar to “glandular fever” the malaria patients with moderately elevated atypical lymphocyte counts did not exhibit such physical signs. Their lymph nodes and spleens were not enlarged. An increased number of atypical lymphocytes has usually been associated with infectious mononucleosis, some viraemias, and other diseases. In a review article (WOOD, 1967) malaria and quinine were listed as “doubtful or poorly documented causes of atypical lymphocytosis” but no references were provided. We therefore present our findings on the patients with malaria. We are, etc., R. D. PARGLE,* c.
LADD.
*Assistant Chief, Department of Pathology, USPHS Hospital, Staten Island, New York, U.S.A. 17 February,
1969 Current Address : (Dr. Paegle) Department of Pathology, Brooklyn-Cumberland Medical Center, Brooklyn, New York, 11201.
121 DeKalb
Avenue,
REFERENCES
J. W., Critique-Hematology “Check Sample” No. H-26, American Clinical Pathologists, Commission on Continuing Education, Council tology, N.P. 1966. DOWNEY, H., MCKINLAY, C. A. (1923). Arch. intern. Med., 32, 82. WOOD, A. T., FRENKEL, E. P. (1967). Am. J. Med., 42,923. ROBBINS, M. (1959). Am. J. Med. Techn., 25, 87. SIIM, J. CHR. (1956). Arm. N.Y. Ad. Sci., 64, 185. BEVERLEY, J. K. A., BEATTIE, C. P. (1958). Lancet, 2, 379. REBUCK,
CILIARY
STRUCTURES
IN
THE
MICROFILARIA
Society of on Hema-
OF LOALOA
S&-Recently KOZEK (1968) reported unusual “cilia” in the microfilaria of Dirojilaria immitis, which differed from normal kineto-cilia in that they did not show the usual pattern of 9 + 2 microtubules. The “cilia” were located within paired channels in the cephalic Each cephalic channel contained a maximum of 9 and caudal regions of the microfilaria. “cilia” at its base, although only 3-5 of these reached the channel orifice. The caudal channels were shorter, and each contained only one “cilium”. In this laboratory I have found these “cilia” also in the microfilariae of Loa loa, In the region of the nerve ring there recovered from the blood of Mandrillus leucophaeus. are several dendritic processes which extend forward into the posterior part of the cephalic which become organized to show space. These processes contain numerous microtubules, a “g-fold” symmetry; each process then resembles a “cilium”. Two channels, resembling those described by Kozek, originate in the posterior part of the cephalic space, and open near the anterior tip of the microfilaria. Each channel has a maximum diameter of 1.3 p taper to about 0 -25 p in at its base, and encloses up to 9 “cilia” (Fig. 1). The ChaMelS diameter near the anterior end of the microfilaria, but their apertures differ in appearance.
CORRESPONDENCE
(ToFacePage290)
291
CORRESPONDENCE
One aperture lies near the anterior tip of the microfilaria, but only one of the nine “cilia” reaches its orifice. The other channel turns obliquely before reaching the tip, and 3 “cilia” reach its orifice (Figs; 2 and 3). The aperture of each cephalic channel is filled with a plug of dense material, and the anterior tips of the “cilia” lie in close apposition to these plugs (Fig. 3). The cephalic “cilia” measure approximately 0 ~2 p in diameter at their point of origin within the channels, but distally they are slightly smaller. The “cilia” are surrounded by a layer of dense material (Figs. 2 and 3). The “9-fold” symmetry is lost in the distal ends of the “cilia”, and the microtubules show a wide variation in both number and arrangement. In addition to those “cilia” which are enclosed within the ceuhalic channels. I have observed other “cilia” within the cephalic space. There appear & be 8 of these “cilia” (Fig. 2), and I have never found them to be enclosed within channels. They extend to the anterior tip of the microfilaria, where they probably terminate in the cephalic papillae (Fig, 4). The number and arrangement of the microtubules vary along the length of these eight “cilia”. A central channel is seen in transverse sections through the anterior part of the microfilaria (Fig. 2), and this probably corresponds to the pharyngeal thread described by LAURENCEand SIMPSON(1968), from light microscopy. At the posterior end of the microfilaria there are 2 caudal ciliary channels, which measure approximately 0.3 p in diameter; each contains only one “cilium“ (Fig. 5). The caudal “cilia” measure annroximatelv 0.25 u in diameter. and distallv thev are invested with a thick coat of den;; material. * The orifice of each channel is fiiled with a plug of dense material which is similar to that seen in the cephalic channels. The function of these unusual “cilia” is not yet clear. Kozek suggested that in Dirofilurz’u immitis thev mieht be sensorv structures associated with the develonine am&ids and phasmids. The bcc&ence of cephalic papillae in the microfllaria of Loa lo; indicates that at least some of the characteristics of the adult worm may be recognized in the prejuvenile stage. Therefore it seems likely that the cephalic and caudal ciliary channels are indeed the precursors of the amphids and phasmids. According to the general account of periodicity set out by HAWKING(1967), microfilariae should be sensitive to minute differences in oxygen tension at both their anterior and posterior ends. If the cephalic and caudal ciliary channels are sensory organelles, it seems possible that their function might be to detect such changes in the environment. I am, etc., DIANE J. MCLAREN. Division of Parasitology, National Institute for Medical Research, Mill Hill, London, N.W.7. 20 February, 1969. REFERENCES
F. (1967). Proc. Roy. Sot. B., 169, 59. KOZEK,W. J. (1968). J. Purasit., 54, 838. LAURENCE, B. R. & SIMPSON, M. F. (1968). J. Helminth., HAWKING,
FIG. FIG. FIG. FIG. FIG.
42, 309.
1. Transverse section near the base of one cephalic ciliary channel. x 57,000. 2. Transverse section near the anterior tip of the microfilaria. x 33,000. 3. Longitudinal section to show the apertures of the cephalic ciliary channels. x 42,000. 4. Section through the anterior tip of the microfilaria, showing one of the cephalic papillae, and the aperture of one cephalic ciliary channel. X 50,000. 5. Transverse section through the posterior region of the microfilaria, to show the two caudal ciliary channels. x 40,000. KEY TO
C-cilium CA-caudal ciliary channel GE-cephalic ciliary channel CP-cephalic papilla
LETTERING
OF FIGURES
M-muscle P-plug PT-pharyngeal S-sheath.
thread