A Giardia varani Lavier, 1923-like flagellate was found in the feces of a captive water monitor, Varanus salvator, originally caught wild from an unknown location in Malaysia. The parasite is similar in size and shape to Giardia lamblia, except that median bodies are rare and cysts are binucleate. A description of both the trophozoite and cyst stage of this flagellate is provided.
The synlophe of Batrachonema synaptospicula Yuen, 1965 collected from Rana limnocharis Boie, 1835 of peninsular Malaysia was found to be identical morphologically to that in the specimens from Rana narina Stejneger, 1901 of Okinawa, and R. limnocharis of Taiwan. In the midbody, 20-22 ridges are present, and the ridges increase gradually in size and are oriented from right to left in the dorsal and left ventral fields, whereas the right ventral ridges are small and almost perpendicular to the body wall. The orientation of ridges from right to left is considered to be a key characteristic of the genus Batrachonema. Because Amphibiophilus ranae Wang et al., 1978 and Amphibiophilus sp. from R. limnocharis of south China are regarded to be conspecific with B. synaptospicula, this nematode is surmised to be distributed widely in southeast and east Asia.
Schistosoma malayensis n. sp., a member of the Schistosoma japonicum complex is described from Rattus muelleri in Peninsular Malaysia and 2 strains are characterized. The only morphological differences noted among adults from natural hosts were that S. malayensis are in general smaller than S. mekongi and S. japonicum. But these differences may be the result of host-induced variations and therefore are of little taxonomic value. To minimize the effects of host-induced variations, adult worms recovered from laboratory mice with similar worm burdens at 50-56 days postinfection were compared. These comparisons revealed only minor morphometric differences among these 3 species. Schistosoma malayensis eggs from naturally and experimentally infected hosts are most similar to those of S. mekongi, with eggs of both species being, in general, smaller than those of S. japonicum. The egg index for S. malayensis is usually higher than for S. japonicum and lower than for S. mekongi. Differences were noted in the developmental rates in mice for 2 isolates of S. malayensis, S. mekongi, and S. japonicum (Philippine strain), but relatively large differences observed between isolates of S. malayensis indicate that, in this case, the developmental rate is not a useful taxonomic character. Schistosoma malayensis is erected principally on the basis of differences, reported elsewhere, in the life histories and in the electrophoretic migration patterns of isoenzymes of adult worms as compared to S. mekongi and S. japonicum. These comparisons indicate that S. malayensis is more closely related to S. mekongi than to S. japonicum.
Empruthotrema stenophallus n. sp. (Monogenea: Monocotylidae) is described from specimens from the nasal tissue of the blue-spotted maskray Dasyatis kuhlii (Muller and Henle, 1841) collected in shallow waters off Pulau Banggi and Pulau Mabul, Sabah, Borneo, Malaysia. This is the first monogenean species to be described from an elasmobranch collected from Sabah. E. stenophallus can be distinguished from the other 6 members of the genus by the morphology of the sclerotized male copulatory organ, which is narrow, short, and distally tapered. E. dasyatidis Whittington and Kearn, 1992, previously documented from the nasal tissue of several of elasmobranch species from Australia, is recorded from 8 host species distributed around Malaysian Borneo. These represent new host and locality records for this monocotylid. The difficulties in identifying species of Empruthotrema and the apparent lack of host specificity by some members of the genus are discussed.
Haemaphysalis (Garnhamphysalis) mjoebergi Warburton was reported from four male specimens from Sarawak, Borneo. We redescribe herein the male, from three specimens from Sarawak and 24 from Lampung District, Sumatra, and describe the female from 24 specimens from Lampung. Male structural variation in the dental formula and development of the coxa IV spur and segments of legs III and IV is unusual or unique in the genus Haemaphysalis. "Atypical" males might easily be misidentified. This species provides an ideal model for experimental study of population genetics and evolutionary processes and of biological factors influencing body size and structural variation in the genus Haemaphysalis. The sambar deer, Cervus unicolor brookei Hose (Sarawak) and C. unicolor equinus Cuvier (Sumatra), appears to be the chief host in humid, marshy, lowland forests and secondary growth. Single collections were from a human and a domestic cow. The dynamics and vector potential of this tick should be investigated in environments being exploited for human settlement and cattle breeding.
Two new nematodes belonging to the subfamily Nippostrongylinae (Nematoda: Trichostrongyloidea: Heligmonellidae) are described based on specimens from endemic murines of Sulawesi, Indonesia: Hasanuddinia maxomyos n. gen., n. sp. from Maxomys musschenbroekii and Eropeplus canus, and Heligmonoides musseri n. sp. from M. musschenbroekii, E. canus, and Margaretamys elegans. Hasanuddinia is closest to Rattusstrongylus of Malaysian rats in lacking a carene and in having a lateromedian gradient in the size of the synlophe ridges in the ventral side of the midbody but is distinguished in that the dorsal ray is divided in the distal half. Heligmonoides musseri most resembles H. bulbosus of Maxomys whiteheadi of Malaysia in having a carene supported by slender ridges of which the proximal portion is not thickened but is distinguished in having longer externodorsal rays and longer spicules. The ancestors of the present Sulawesi nematodes seem to have originated on the southeast Asian continent, were introduced to Sulawesi with the dispersal of some murines, and subsequently speciated.
Toxocara malaysiensis n. sp. from the small intestine of the domestic cat (Felis catus L.) in Malaysia is described and illustrated. This ascaridoid nematode was previously assumed to be Toxocara canis, which it superficially resembles, or designated Toxocara sp. cf. canis. The new species differs from T. canis in the shape of the cervical alae in cross section, spicule length, and the lip structure. It is also distinct from other species assigned to Toxocara.
Pterobdella occidentalis n. sp. (Hirudinida: Piscicolidae) is described from the longjaw mudsucker, Gillichthys mirabilis Cooper, 1864, and the staghorn sculpin, Leptocottus armatus Girard, 1854, in the eastern Pacific, and the diagnosis of Pterobdella abditovesiculata (Moore, 1952) from the 'o'opu 'akupa, Eleotris sandwicensis Vaillant and Sauvage, 1875, from Hawaii is amended. The morphology of both species conforms with the genus Pterobdella in possessing a spacious coelom, well-developed nephridial system, and 2 pairs of mycetomes. Originally described as Aestabdella abditovesiculata, P. occidentalis (present along the U.S. Pacific Coast), can be distinguished from most congeners by its metameric pigmentation pattern and diffuse pigmentation on the caudal sucker. Based on mitochondrial gene sequences, including cytochrome c oxidase subunit I (COI) and NADH dehydrogenase subunit I (ND1), P. occidentalis forms a distinct polyphyletic clade with Pterobdella leiostomi from the western Atlantic. Based on COI, ND1, and the 18S rRNA genes, other leech species most closely related to P. occidentalis include Pterobdella arugamensis from Iran, Malaysia, and possibly Borneo, which likely represent distinct species, and Pterobdella abditovesiculata from Hawaii, one of only a few endemic fish parasites in Hawaii. Like P. abditovesiculata, P. arugamensis, and Petrobdella amara, P. occidentalis is often found in estuarine environments, frequently infecting hosts adapted to a wide range of salinity, temperature, and oxygen. The physiological plasticity of P. occidentalis and the longjaw mudsucker host, and the ease of raising P. occidentalis in the lab, make it an excellent candidate for the study of leech physiology, behavior, and possible bacterial symbionts.
Three species of flying fox (Pteropus hypomelanus, P. vampyrus, and P. lylei) from Malaysia and Vietnam were screened for apicomplexan parasites by thin blood smears and polymerase chain reaction. Only 1 of 16 bats sampled from 3 localities in southeast Asia was found to be infected (P. hypomelanus from Pulau Pangkor, Malaysia). We observed micro- and macrogametocytes, with morphology consistent with Hepatocystis sp. parasites, using light microscopy. Phylogenetic analysis of the cytochrome b gene showed that the parasite from P. hypomelanus groups with 2 published sequences from Hepatocystis spp., including one from Cynopterus brachyotis, another fruit bat in the Pteropodidae.
The ultrastructure of the human skeletal muscle sarcocyst found in Malaysia is reported. Sarcocyst-positive, formalin-fixed tongue tissues were postfixed in osmium tetroxide. The primary cyst wall consisted of a thin membrane supported by osmiophilic material that was interrupted regularly by vesicle-like invaginations. Although there were no cytophaneres, stubby protrusions of the primary wall were observed. These protrusions were accentuated by dense, curvilinear material externally. The primary wall was wavy over about half the cross section of the cyst. The granular ground substance underlying the primary wall occasionally contained hitherto undescribed coiled microtubular structures. Branching septa extended from the ground substance into the cyst, separating mature merozoites into compartments. A few peripheral metrocytes and many laminated myelin figure-like structures, probably degenerating merozoites, were found. Although the human muscular sarcocyst has the same basic ultrastructure as those found in other animals, the stubby protrusions and coiled microtubular structures in the ground substance have not been described previously in nonhuman animals.