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Possible protozoan parasites in the faeces of a Lophuromys flavopunctatus naturally infected with Sarcocystis
LABORATORY MEETING
5,
Dr. Tranakchit Harinasuta : Amoebic liver abscess Photographs were shown illustrating the results of aspiration and treatment with emetine hydrochloride, chloroquine and Aminosidine. Abscess cavities were demonstrated by X-ray after injections of opaque iodides.
London School of Hygiene and Tropical Medicine DEPARTMENT OF PARASITOLOGY
D r . R. L a i n s o n :
A Trypanosoma cruzi-like t r y p a n o s o m e in the
coati (Nasua narica) from British Honduras A parasite morphologically indistinguishable from Trypanosoma (Schizotrypanum) cruzi was found in a " coati ", Nasua narica (Carnivora, Procyonidae), from the E1 Cayo District, British Honduras. Slides were shown, together with others of known T. cruzi for comparison. Although Chagas's disease has not yet been reported from the Colony, numerous cases have been described from neighbouring Guatemala and Mexico. It is likely, therefore, that the disease does exist in British Honduras, but has so far not been diagnosed. A more detailed account is in preparation. D r . A. M. M a n d o u r , a n d D r . J. J. S h a w : A Sarcocystis species i n a t w o - t o e d sloth, Choloepus hoffmanni hoffmanni, from Central America One cyst r u n n i n g through 35 serial sections (5~ thick), was found in a thigh muscle of a two-toed sloth, Choloepus h. hoffmanni. The maximum breadth was 54 ~. The cyst was finely trabeculated and the cyst wall was thin and devoid of cytophaneres. The spores were very minute and there was no tissue reaction around the parasite. No sarcocysts were found in the cardiac muscle. This appears to be the second report of Sarcocystis from a Hoffman's sloth ; the first report being that by Darling (1915). Montero-Gei (1956) reported a parasite in the skeletal muscle of a three-toed sloth (Bradypus infuscatus griseus). Because of the absence of a cyst wall and trabeculae he considered that it was not related to Sarcocystis. However, in our experience such characters are not necessarily detectable in all the developmental stages of Sarcocystis. Moreover, the parasite found by Montero-Gei was lying within a hypertrophied muscle fibre, which is a common finding in this parasite, and this suggests that it may well have been a Sarcocystis sp. References : Darling, S. (1915). J. Parasit., 1, 113 Montero-Gei, F. (1956). Rev. Biol. trop. S. Jose, 4, 41. D r . A. M. M a n d o u r : 1. P o s s i b l e
protozoan
parasites
in the faeces
o f a Lophuromys
flavopunetatus n a t u r a l l y i n f e c t e d w i t h Sarcocystis A.
Fresh faeces : 1. Banana-shaped organisms.
Some of them have one nucleus, but the majority possess two nuclei. One or more vacuoles, probably corresponding to each nucleus, are observed. The parasite appears to have a protective capsule. The organisms possessing one nucleus and one vacuole are reminiscent of Sarcocystis spores. 2. Amoeba-like organisms. They generally look like amoebulae but the nuclear membrane and the karyosome could not be detected. The cytoplasm is vacuolated and contains one, or rarely two, rounded compact bodies which stain dark blue with Giemsa and black with Heidenhain stain.
3. A few minute cyst-like organisms with excentric nucleus and one or two cytoplasmic inclusions. They did not grow on nutrient media. B. Faeces kept wet at room temperature : T h e banana-shaped and tile amoeba-like organisms disappeared between the 10th and the 15th days, while the cyst-like organisms became very numerous. No cyst wall is detected (Heidenhain stain).
6
LABORATORY MEETING
Natural intracystic morphological changes of Sarcocystis tenella spores A. Sections stained with haematoxylin and eosin : Pear-shaped, oval and rounded organisms are found in the centre of some macroscopic sarcocysts. T h e rounded forms possess an excentric deeply stained compact body. The cytoplasm appears to be granular especially at one side. B. Smears stained with Giemsa : Rounded forms of the parasite are also found in smears, which confirms the first observation. A bluish substance, presumably secreted by the spores, is found to fill the gap formed between either ends of the spore. Shrinkage of this substance perhaps approximates the two extremities of the spore, which eventuaily becomes a rounded body. T h e bluish substance thus appears as an excentric cytoplasmic inclusion, while the nucleus is not changed. 2.
3.
Two quick staining methods for permanent w h o l e - m o u n t preparation o f Sarcoeystis A. Staining with Gram's iodine : (1) A small piece of muscle is well compressed between two slides. (2) It is fixed in 70% alcohol for 10 minutes. (3) It is transferred to strong Gram's iodine until the contour of the specimen becomes deeply stained. (4) I t is differentiated momentarily in methylated spirit. (5) It is dipped in terpineol until the specimen becomes transparent (it takes 10 to 30 minutes according to the thickness of the material). (6) I t is mounted in canada balsam. T h e cysts are brownish and the muscles yellow. This staining method is based on the fact that Sarcocystis spores contain glycogen in their cytoplasm. B. Staining with acetic acid alum carmine : After fixation, the material is transferred to a watch-glass containing the staining reagent (for ½ hour), differentiated in i % acid alcohol, then dehydrated in 95% alcohol for 5 minutes. It is cleared in terpineol, and mounted in canada balsam. T h e sarcocysts stand out from the very pale muscle fibres as strongly staining pink tubes or tapes. Small cysts can easily be detected b y this technique. L. A. M. O m r a m (Mrs. Mandour, A.M.) introduced by Dr. J. J. Shaw : 1. Exoerythrocytic schizonts o f Plasmodium (G.) pinottii in canaries Two canaries were inoculated intramuscularly with pigeon's blood infected with Plasmodium (G.) pinottii. On the 20th day of inoculation, one of them died suddenly. Brain smears and sections revealed a considerable number of exoerythrocytic schizonts. However, blood stages were very scanty. T h e other ~anary was killed 2 days later. No exoerythrocytic schizonts were detected. Reference : G a m h a m , P. C. C. & Killick-Kenderick, R. (1964) : Trans. R. Soc. trop. Med. Hyg., 58, 4. 2.
Successful infection o f chick e m b r y o s by intravenous inoculation o f Plasmodium (G.) pinottii About 28% of the inoculated embryos took the infection. After hatching, some baby chicks were at first negative, but they showed the parasite in their blood a few days later. S o m e o f t h e m could rid themselves of the infection, but others succumbed as a result of high parasitaemia. Dr. G. S. Nelson and Mr. E. J. Blackie : A n Alaska strain o f Trichinella spiralis o f l o w infectivity to laboratory rats Trichinella spiralis is the only species in the primitive aphasmid family Trichinellidae ; it has long been regarded as the best example of a helminth lacking in host specificity. T h e parasite is found in a wide range of mammalian hosts and this ubiquity is often regarded as evidence of uniformity throughout its range. Rats and domestic pigs have aiways been considered to be hosts par excellence for T. spiralis, but this parasitological dogma was upset by the discovery of a strain of T. spiralis in East African carnivores, which was of exceptionally low infectivity to laboratory rats, wild rats and domestic pigs (Nelson m~d Mukundi, 1963). Further studies have shown that the East A f r i c a n 1". spiralis is not unique ; similar differences in infectivity have been found in other geographical strains of the parasite. Thanks to Dr. R. L. Rausch, Professor J. J. C. Buckley, Professor Z. Kozar and Professor S. E. Gould, it was possible to compare the Kenya strains from hyaenas
5,
Dr. Tranakchit Harinasuta : Amoebic liver abscess Photographs were shown illustrating the results of aspiration and treatment with emetine hydrochloride, chloroquine and Aminosidine. Abscess cavities were demonstrated by X-ray after injections of opaque iodides.
London School of Hygiene and Tropical Medicine DEPARTMENT OF PARASITOLOGY
D r . R. L a i n s o n :
A Trypanosoma cruzi-like t r y p a n o s o m e in the
coati (Nasua narica) from British Honduras A parasite morphologically indistinguishable from Trypanosoma (Schizotrypanum) cruzi was found in a " coati ", Nasua narica (Carnivora, Procyonidae), from the E1 Cayo District, British Honduras. Slides were shown, together with others of known T. cruzi for comparison. Although Chagas's disease has not yet been reported from the Colony, numerous cases have been described from neighbouring Guatemala and Mexico. It is likely, therefore, that the disease does exist in British Honduras, but has so far not been diagnosed. A more detailed account is in preparation. D r . A. M. M a n d o u r , a n d D r . J. J. S h a w : A Sarcocystis species i n a t w o - t o e d sloth, Choloepus hoffmanni hoffmanni, from Central America One cyst r u n n i n g through 35 serial sections (5~ thick), was found in a thigh muscle of a two-toed sloth, Choloepus h. hoffmanni. The maximum breadth was 54 ~. The cyst was finely trabeculated and the cyst wall was thin and devoid of cytophaneres. The spores were very minute and there was no tissue reaction around the parasite. No sarcocysts were found in the cardiac muscle. This appears to be the second report of Sarcocystis from a Hoffman's sloth ; the first report being that by Darling (1915). Montero-Gei (1956) reported a parasite in the skeletal muscle of a three-toed sloth (Bradypus infuscatus griseus). Because of the absence of a cyst wall and trabeculae he considered that it was not related to Sarcocystis. However, in our experience such characters are not necessarily detectable in all the developmental stages of Sarcocystis. Moreover, the parasite found by Montero-Gei was lying within a hypertrophied muscle fibre, which is a common finding in this parasite, and this suggests that it may well have been a Sarcocystis sp. References : Darling, S. (1915). J. Parasit., 1, 113 Montero-Gei, F. (1956). Rev. Biol. trop. S. Jose, 4, 41. D r . A. M. M a n d o u r : 1. P o s s i b l e
protozoan
parasites
in the faeces
o f a Lophuromys
flavopunetatus n a t u r a l l y i n f e c t e d w i t h Sarcocystis A.
Fresh faeces : 1. Banana-shaped organisms.
Some of them have one nucleus, but the majority possess two nuclei. One or more vacuoles, probably corresponding to each nucleus, are observed. The parasite appears to have a protective capsule. The organisms possessing one nucleus and one vacuole are reminiscent of Sarcocystis spores. 2. Amoeba-like organisms. They generally look like amoebulae but the nuclear membrane and the karyosome could not be detected. The cytoplasm is vacuolated and contains one, or rarely two, rounded compact bodies which stain dark blue with Giemsa and black with Heidenhain stain.
3. A few minute cyst-like organisms with excentric nucleus and one or two cytoplasmic inclusions. They did not grow on nutrient media. B. Faeces kept wet at room temperature : T h e banana-shaped and tile amoeba-like organisms disappeared between the 10th and the 15th days, while the cyst-like organisms became very numerous. No cyst wall is detected (Heidenhain stain).
6
LABORATORY MEETING
Natural intracystic morphological changes of Sarcocystis tenella spores A. Sections stained with haematoxylin and eosin : Pear-shaped, oval and rounded organisms are found in the centre of some macroscopic sarcocysts. T h e rounded forms possess an excentric deeply stained compact body. The cytoplasm appears to be granular especially at one side. B. Smears stained with Giemsa : Rounded forms of the parasite are also found in smears, which confirms the first observation. A bluish substance, presumably secreted by the spores, is found to fill the gap formed between either ends of the spore. Shrinkage of this substance perhaps approximates the two extremities of the spore, which eventuaily becomes a rounded body. T h e bluish substance thus appears as an excentric cytoplasmic inclusion, while the nucleus is not changed. 2.
3.
Two quick staining methods for permanent w h o l e - m o u n t preparation o f Sarcoeystis A. Staining with Gram's iodine : (1) A small piece of muscle is well compressed between two slides. (2) It is fixed in 70% alcohol for 10 minutes. (3) It is transferred to strong Gram's iodine until the contour of the specimen becomes deeply stained. (4) I t is differentiated momentarily in methylated spirit. (5) It is dipped in terpineol until the specimen becomes transparent (it takes 10 to 30 minutes according to the thickness of the material). (6) I t is mounted in canada balsam. T h e cysts are brownish and the muscles yellow. This staining method is based on the fact that Sarcocystis spores contain glycogen in their cytoplasm. B. Staining with acetic acid alum carmine : After fixation, the material is transferred to a watch-glass containing the staining reagent (for ½ hour), differentiated in i % acid alcohol, then dehydrated in 95% alcohol for 5 minutes. It is cleared in terpineol, and mounted in canada balsam. T h e sarcocysts stand out from the very pale muscle fibres as strongly staining pink tubes or tapes. Small cysts can easily be detected b y this technique. L. A. M. O m r a m (Mrs. Mandour, A.M.) introduced by Dr. J. J. Shaw : 1. Exoerythrocytic schizonts o f Plasmodium (G.) pinottii in canaries Two canaries were inoculated intramuscularly with pigeon's blood infected with Plasmodium (G.) pinottii. On the 20th day of inoculation, one of them died suddenly. Brain smears and sections revealed a considerable number of exoerythrocytic schizonts. However, blood stages were very scanty. T h e other ~anary was killed 2 days later. No exoerythrocytic schizonts were detected. Reference : G a m h a m , P. C. C. & Killick-Kenderick, R. (1964) : Trans. R. Soc. trop. Med. Hyg., 58, 4. 2.
Successful infection o f chick e m b r y o s by intravenous inoculation o f Plasmodium (G.) pinottii About 28% of the inoculated embryos took the infection. After hatching, some baby chicks were at first negative, but they showed the parasite in their blood a few days later. S o m e o f t h e m could rid themselves of the infection, but others succumbed as a result of high parasitaemia. Dr. G. S. Nelson and Mr. E. J. Blackie : A n Alaska strain o f Trichinella spiralis o f l o w infectivity to laboratory rats Trichinella spiralis is the only species in the primitive aphasmid family Trichinellidae ; it has long been regarded as the best example of a helminth lacking in host specificity. T h e parasite is found in a wide range of mammalian hosts and this ubiquity is often regarded as evidence of uniformity throughout its range. Rats and domestic pigs have aiways been considered to be hosts par excellence for T. spiralis, but this parasitological dogma was upset by the discovery of a strain of T. spiralis in East African carnivores, which was of exceptionally low infectivity to laboratory rats, wild rats and domestic pigs (Nelson m~d Mukundi, 1963). Further studies have shown that the East A f r i c a n 1". spiralis is not unique ; similar differences in infectivity have been found in other geographical strains of the parasite. Thanks to Dr. R. L. Rausch, Professor J. J. C. Buckley, Professor Z. Kozar and Professor S. E. Gould, it was possible to compare the Kenya strains from hyaenas