Recurrent outbreaks of muscular sarcocystosis among tourists visiting islands in Malaysia have focused international attention on sarcocystosis, a disease once considered rare in humans. Sarcocystis species require two hosts, definitive and intermediate, to complete their life cycle. Humans can serve as definitive hosts, with intestinal sarcocystosis for two species acquired from eating undercooked meat: Sarcocystis hominis, from beef, and Sarcocystis suihominis, from pork. Symptoms such as nausea, stomachache, and diarrhea vary widely depending on the number of cysts ingested but appear more severe with pork than with beef. Humans serve as intermediate hosts for Sarcocystis nesbitti, a species with a reptilian definitive host, and possibly other unidentified species, acquired by ingesting sporocysts from feces-contaminated food or water and the environment; infections have an early phase of development in vascular endothelium, with illness that is difficult to diagnose; clinical signs include fever, headache, and myalgia. Subsequent development of intramuscular cysts is characterized by myositis. Presumptive diagnosis based on travel history to tropical regions, elevated serum enzyme levels, and eosinophilia is confirmed by finding sarcocysts in muscle biopsy specimens. There is no vaccine or confirmed effective antiparasitic drug for muscular sarcocystosis, but anti-inflammatory drugs may reduce symptoms. Prevention strategies are also discussed.
The parasitic protozoan fauna in sixty-six anurans comprising of Duttaphrynus melanostictus, Phrynoidis juxtaspera, Hylarana erythraea and Polypedates leucomystax collected from Zoo Negara Malaysia was investigated. The distribution and prevalence rate of parasitic species in the digestive tract and blood were examined. Seven species of intestinal protozoa (Opalina ranarum, Cepedea dimidiata, Nycthetorus cordiformis, Entamoeba ranarum, Iodamoeba butschlii, Endamoeba blattae, and Tritrichomonas sp.) and two species of blood protozoa (Lankesterella sp. and Trypanosoma sp.) were recorded. Opalina ranarum was the most common protozoan found in the rectum and intestine (prevalence rate: 34.8%) infecting all host species, with P. juxtaspera heavily infected with the parasite, whereas Tritrichomonas sp. was the least prevalent intestinal species infecting only D. melanostictus. Both Lankesterella sp. and Trypanosoma sp. were found in the blood of H. erythraea.
Sampling of a large number of elasmobranchs from coastal waters off Borneo revealed the presence of five new species of Dollfusiella Campbell & Beveridge, 1994 (Trypanorhyncha: Eutetrarhynchidae), namely D. angustiformis n. sp., D. hemispinosa n. sp., D. spinosa n. sp., D. imparispinis n. sp. and D. parva n. sp. Dollfusiella angustiformis n. sp. is described from the spiral intestines of four species of the dasyatid stingray genus Himantura Müller & Henle from both the Indonesian and Malaysian parts of Borneo. All the other species were obtained from Malaysian Borneo. Dollfusiella hemispinosa n. sp. is described from the spiral intestines of three species of Himantura, whereas D. spinosa n. sp. was obtained from several specimens of Pastinachus solocirostris Last, Manjaji & Yearsley (Dasyatidae) as well as from Taeniura lymma 1 (sensu Naylor et al., 2012) (Dasyatidae), Neotrygon kuhlii 2 (sensu Naylor et al., 2012) (Dasyatidae), and Glaucostegus cf. typus (sensu Naylor et al., 2012) (Rhinobatidae). Dollfusiella imparispinis n. sp. is described from the spiral intestine of a single specimen of Chiloscyllium punctatum Müller & Henle (Hemiscyllidae) from the South China Sea off Sarawak, whereas D. parva n. sp. was obtained from several species of Himantura. Specimens of the five novel taxa possess scoleces covered with enlarged microtriches, a morphological characteristic exhibited by several other congeners. However, the new species differ from all congeners by possessing unique patterns of oncotaxy as well as combinations of additional morphological features. The number of valid species within Dollfusiella is increased to 26. For this reason, a key for the species of Dollfusiella is provided. Furthermore, novel information on hosts and geographic distribution is provided for two previously described species of Dollfusiella, D. michiae (Southwell, 1929) and D. spinulifera (Beveridge & Jones, 2000). The latter species differs slightly from the original description and shows a much higher variability with regard to the lengths of the scolex and muscular bulbs and the number of testes. These variable characters subdivided specimens of D. spinulifera into relatively distinct groups. However, the specimens did not differ in their oncotaxy and are considered to represent a single variable species.
A survey was undertaken to investigate the prevalence of intestinal and blood parasites among wild rats in urban area of Kuala Lumpur, Malaysia. A total of 137 stool and blood samples were collected from wild rats from Sentul and Chow Kit areas. Five species of rats were captured and supplied by Kuala Lumpur City Hall. The most common was Rattus rattus diardii (Malayan Black rat), 67%, followed by Rattus norvegicus (Norway rat), 10%, Rattus argentiventer (rice-field rat), 10%, Rattus tiomanicus (Malaysian field rat), 9% and Rattus exulans (Polynesian rat), 4%. Rattus rattus diardii is commonly known to live in human environment and they are normally identified as pests to human community. More male rats were captured (61%) compared to female (39%). Out of 137 samples, 81.8% samples were positive with intestinal parasites, with 86.2% from Sentul area and 78.5% from Chow Kit area. Six different parasites were detected. The most common intestinal helminth parasite detected was Nippostrongylus brasiliensis (80.3%), followed by Hymenolepis nana (23.4%), Capillaria hepatica (13.9%) and Hymenolepis diminuta (2.9%). Intestinal protozoan detected was Entamoeba histolytica/E. dispar (8.8%). Trypanosoma lewisi (1.5%) was the only blood parasite detected.
School children from 3 primary and 2 secondary schools in Sarawak were examined for the presence of gastrointestinal helminths. One primary school and 1 secondary school were located in a town (Serian), the other primary and secondary schools were in the countryside outside Serian. The intestinal helminths detected were Ascaris lumbricoides, Trichuris trichiura, Enterobius vermicularis and hookworm. Children from the rural schools had higher numbers of eggs in their faeces than those from the Serian schools. Children from the rural primary schools had higher number of eggs than those from the rural secondary school. The prevalence of Ascaris, Trichuris and hookworms in male and female and in primary and secondary school children was recorded.
A light and electron microscopic study of Sarcocystis orientalis sp. n. was made. The life cycle of this parasite is in two hosts. Gametogony is in the intestinal epithelial cells of a predator, Python reticulatus. Isospora-like oocysts developed. Sporocysts average 9.1 by 7.7 mum. Rats (Rattus norvegicus) were infected with sporocysts and asexual stages developed. Ten days after infection large zoites (average 7.85 by 2.48 mum) were observed free in peripheral blood and within white blood cells. Small schizonts producing merozoites 2-3 mum long were seen in lung tissue. Tissue cysts developed in skeletal muscle and produced numerous cystozoites (average 5.53 by 1.38 mum). Fine structure was similar to previously described Sarcocystis spp.
We identified and characterized a new cosmocercid nematode species, Cosmocercoides wuyiensis n. sp., through microscopic examination and sequencing of the partial small ribosomal RNA gene (18S rDNA), internal transcribed spacer (ITS) and mitochondrial cytochrome c oxidase subunit 1 (COI) genes. The new species was isolated from the intestine of the Asiatic frog Amolops wuyiensis Liu and Hu, 1975 captured from four localities of the Anhui province in south-east China. Among the 25 recorded species of the Cosmocercoides genus, the morphology of C. wuyiensis n. sp. is closest to that of C. kiliwai and C. malayensis, which were isolated from various Mexican frog and Malaysian lizard species, respectively. However, C. wuyiensis n. sp. displayed several distinguishing features, such as small size of the male body, two spicules of unequal lengths in the male, small gubernaculum, pre-, ad- and post-cloacal caudal rosette papillae in the ratio of 18-24:2:6 and simple papillae in the ratio of 14:multiple:4, circle and number of punctation in each rosette at 1:11-16, sharply conical tail-end and the presence of lateral alae and somatic papillae in both sexes. BLAST and the phylogenetic analyses of the 18S rDNA and ITS sequences indicated that C. wuyiensis n. sp. belonged to the genus Cosmocercoides, while that of the COI gene sequence of C. wuyiensis n. sp. showed 16.36% nucleotide divergence with C. pulcher and 47.99% nucleotide divergence with C. qingtianensis. The morphological and molecular characterization of C. wuyiensis n. sp. provides new taxonomic data for this genus.
Thirty snakehead fish, Channa micropeltes (Cuvier, 1831) were collected at Lake Kenyir, Malaysia. Muscle, liver, intestine and kidney tissues were removed from each fish and the intestine was opened to reveal cestodes. In order to assess the concentration of heavy metal in the environment, samples of water in the surface layer and sediment were also collected. Tissues were digested and the concentrations of manganese (Mn), zinc (Zn), copper (Cu), cadmium (Cd) and lead (Pb) were analysed by using inductively-coupled plasma mass-spectrometry (ICP-MS) equipment. The results demonstrated that the cestode Senga parva (Fernando and Furtado, 1964) from fish hosts accumulated some heavy metals to a greater extent than the water and some fish tissues, but less than the sediment. In three (Pb, Zn and Mn) of the five elements measured, cestodes accumulated the highest metal concentrations, and in remaining two (Cu and Cd), the second highest metal accumulation was recorded in the cestodes when compared to host tissues. Therefore, the present study indicated that Senga parva accumulated metals and might have potential as a bioindicator of heavy-metal pollution.
There are few small animals models for filariasis, even more so for onchocerciasis. Therefore it is difficult to test under drug screening conditions large numbers of potentially macrofilaricidal compounds. One way around this difficulty is to use mice infected with Trichinella spiralis which by reason of anatomical location in the host would show some correlation in antinematode activity between the test and target organisms. This study investigated the activity of 16 compounds against the immature larval stage of T. spiralis. All the nine benzimidazole compounds (albendazole, flubendazole, mebendazole, oxfendazole, oxibendazole 780118, 780120, 790163, and 790392) were active, the most potent being oxfendazole. The benzothiazoles (CGP21306, CGP20376, CGP21833 and CGP24588A) also indicated some anti-nematode activity together with 35vr, an imidazopyridine, but not as marked as the benzimidazole group. However, the organic arsenical compounds (Mel Ga and Mel Ni) showed little activity and this was at a rather highly toxic level. The prospects of using the Trichinella-mouse model as a primary screen to test for potential macrofilaricides are discussed.
Faecal samples of 56 common house crows (Corvus splendens Vieillot) were collected from the Petaling Jaya and Kelang districts of Selangor, peninsular Malaysia, and examined for coccidia. Intestinal tracts of 8 of the above crows wee histologically examined under light microscopy to determine the site of coccidial infection and the endogenous stages present. Fifty three (94.6%) crows had coccidial oocysts morphologically conforming to only one species of Isospora in their faeces at the time they were examined. The sporulated oocysts were found to be Isospora corviae (Ray et al. 1952) which has been emended to I. corvi. These oocysts are redescribed in greater detail. Corvus splendens is a new host record for I. corvi. Coccidial infection was observed in all the intestinal tracts and generally confined to the anterior two thirds of the intestine. The parasites occurred within intestinal epithelial cells, located usually above the host cell nucleus. Developmental stages of both the asexual and sexual phases were found in the epithelium, and are deemed to be the endogenous stages of I. corvi on the basis of the oocysts recovered from the same crows used for histological study. These stages are described here for the first time. The prevalence of I. corvi, its relationship with the host C. splendens, and its probable transmission from C. macrorhynchus are discussed.
Enterobius worms or their eggs, or both, are present in preserved tissue sections or tissue specimens of 259 patients whose medical records are on file at the Armed Forces Institute of Pathology, Washington D.C., U.S.A. The most common site of infection (86.5%) was found to be the lumen of the appendix, where the worms provoke no reaction. Of the 259 patients 11 (4.2%) had worms and/or eggs in granulomas of the abdominal and pelvic peritoneum, and an equal number had granulomas on the peritoneum of the salphinx or on the surface of the ovary. There were also ectopic worms and/or eggs in granulomas on the peritoneum of the small and large intestines (2.7%). These Enterobius granulomas form around degenerating adult worms, around discrete eggs, around clusters of eggs, and, we believe, also around the tracks of migrating worms. Three patients (1.2%) had worms in perianal abscesses. A necrotic granuloma, removed from the lung of one patient, surrounded a degenerating adult worm. This suggests that the worm, carried to the lung as an embolus, impacted in a pulmonary arteriole. A stool specimen of one patient contains eggs of Enterobius, and that of another patient contains an adult Enterobius. This is the largest recorded histopathological study of enterobiasis in man.
Thelohanellus kitauei is a freshwater myxosporean parasite causing intestinal giant cystic disease of common carp. To clarify the life cycle of T. kitauei, we investigated the oligochaete populations in China and Hungary. This study confirms two distinct aurantiactinomyxon morphotypes (Aurantiactinomyxon type 1 and Aurantiactinomyxon type 2) from Branchiura sowerbyi as developmental stages of the life cycle of T. kitauei. The morphological characteristics and DNA sequences of these two types are described here. Based on 18S rDNA sequence analysis, Aurantiactinomyxon type 1 (2048 bp) and Aurantiactinomyxon type 2 (2031 bp) share 99.2-99.4 %, 99.8-100 % similarity to the published sequences of T. kitauei, respectively. The 18S rDNA sequences of these two aurantiactinomyxon morphotypes share 99.4 % similarity, suggesting intraspecific variation within the taxon, possibly due to geographic origin. Phylogenetic analyses demonstrate the two aurantiactinomyxon types clustered with T. kitauei. Regardless, based on 18S rDNA synonymy, it is likely that Aurantiactinomyxon type 1 and 2 are conspecific with T. kitauei. This is the fourth elucidated two-host life cycle of Thelohanellus species and the first record of T. kitauei in Europe.
This study was conducted to determine the prevalence of intestinal parasites among children and adult Orang Aslis (Aborigines) from different locations in Perak. Faecal samples were collected and analyzed using the direct smear and formal ether sedimentation technique. Some of the faecal samples were stained using the Modified Acid fast stain for Cryptosporidium. Nail clippings of the respondents and the soil around their habitat were also analyzed. Of the 77 stool samples examined, 39 (50.6%) were positive for at least one intestinal parasite. The most common parasite detected was Trichuris trichiura (39.0%) followed by Ascaris lumbricoides (26.9%), Entamoeba coli (5.2%), Giardia lamblia (5.2%), Blastocystis hominis (3.9%), hookworm (3.9%), Entamoeba histolytica (1.3%), Iodamoeba butschlii (1.3%) and Cryptosporidium sp. (1.3%) respectively. Some respondents had single parasites (24.7%), some with two parasites (18.2%). Some with three parasites (6.5%) and one had four parasites species (1.3%). The parasites were slightly more common in females (54.7%) than males ((41.7%). The parasites were more common in the 13-20 year age group (90.9%) followed by 1-12 years (69.6%), 21-40 year age group (34.8%) and least in the 41-60 year age group (27.8%). Nail examinations of the respondents did not show any evidence of parasites. One had a mite, three had pollen grains and one had yeast cells isolated from the finger nails. Soil samples taken around their houses showed only one sample with a nematode ova and one with oocyst which was of a non human origin.
Increasing incidence of inflammatory bowel diseases, such as Crohn's disease, in developed nations is associated with changes to the microbial environment, such as decreased prevalence of helminth colonization and alterations to the gut microbiota. We find that helminth infection protects mice deficient in the Crohn's disease susceptibility gene Nod2 from intestinal abnormalities by inhibiting colonization by an inflammatory Bacteroides species. Resistance to Bacteroides colonization was dependent on type 2 immunity, which promoted the establishment of a protective microbiota enriched in Clostridiales. Additionally, we show that individuals from helminth-endemic regions harbor a similar protective microbiota and that deworming treatment reduced levels of Clostridiales and increased Bacteroidales. These results support a model of the hygiene hypothesis in which certain individuals are genetically susceptible to the consequences of a changing microbial environment.
The lecanicephalidean cestodes parasitizing the spiral intestine of the endangered giant freshwater whipray, Urogymnus polylepis (Bleeker), are investigated for the first time. Eight host specimens were collected between 2002 and 2008 at 2 collecting sites off the eastern coast of Borneo: 6 from the Kinabatangan River (Malaysia) and 2 from a fish market in Tarakan (Indonesia). Two of these individuals were found to be infected with a total of 3 new species of TetragonocephalumShipley and Hornell, 1905. Tetragonocephalum georgei n. sp. and Tetragonocephalum opimum n. sp. were recovered from a host specimen from the Kinabatangan River, and Tetragonocephalum levicorpum n. sp. was found parasitizing a host specimen purchased at a fish market in Tarakan. Specimens of each of the new species were prepared for light microscopy; specimens of 2 of the new species were prepared for scanning electron microscopy, and histological sections were prepared for 1 of the new species. The 3 new species are distinct from the 9 valid species of Tetragonocephalum and the 1 species inquirendum based on, for example, total length, number of proglottids and testes, and size of the scolex and acetabula. Tetragonocephalum georgei n. sp. and T. levicorpum n. sp. are unusual among their congeners in that they are euapolytic (i.e., gravid proglottids were not observed) rather than apolytic. They differ from one another in scolex and acetabula size. Tetragonocephalum opimum n. sp. is unusual among its congeners in its possession of vitelline follicles arranged in 2, rather than 3, regions in the proglottid. These new species increase the total number of valid species of Tetragonocephalum to 12 and the total number of known cestodes from U. polylepis to 13 species across 6 genera in 4 orders. This is the first account of lecanicephalideans reported from freshwater. The taxonomic status of each of the 32 nominal taxa historically associated with Tetragonocephalum is re-assessed. Type host identities of all valid species are revised and discussed in light of recent taxonomic efforts in the Dasyatidae Jordan and Gilbert.