Using a sedimentation method, the prevalence of the nodular worm Oesophagostomum stephanostomum (Nematoda: Strongylida) in western lowland gorillas at Moukalaba-Doudou National Park (MDNP), Gabon, was determined in fecal samples collected between January 2007 and October 2011, along with their coprocultures. Concurrently, possible zoonotic Oesophagostomum infections in villagers living near MDNP were assessed from their fecal samples collected during October and November of 2011. In the gorillas, strongylid (Oesophagostomum and/or hookworm) eggs were found in 47 of 235 fecal samples (20.0 %) and Oesophagostomum larvae were detected in 101 of 229 coprocultures (44.1 %). In the villagers, strongylid eggs were found in 9 of 71 fecal samples (12.7 %), but no Oesophagostomum larvae were detected in coprocultures. The internal transcribed spacer (ITS) region of ribosomal RNA gene (rDNA) and cytochrome c oxidase subunit-1 (cox-1) region of mitochondrial DNA (mtDNA) of coprocultured Oesophagostomum larvae were amplified using parasite DNA extracted from 7–25 larvae/sample, cloned into Escherichia coli, and sequenced. Sequenced rDNA contained 353/354-bp long ITS1, 151-bp long 5.8S rDNA, and 227-bp long ITS2. Parts of clones showed variations at 1–3 bases in the ITS1 region at a frequency of 24/68 (35.3 %) and at 1–2 bases in the ITS2 region at a frequency of 7/68 (10.3 %), whereas the 5.8S rDNA was essentially identical. Sequenced cox-1 gene of the parasites, 849 bp in length, showed a higher number of nucleotide variations, mainly at the third nucleotide position of the codon. The majority of clones (27/41 (65.9 %)) had an identical amino acid sequence. These results suggest that at MDNP, Gabon, only a single population of O. stephanostomum with a degree of genetic diversity is prevalent in western lowland gorillas, without zoonotic complication in local inhabitants. The possible genetic variations in the ITS region of rDNA and cox-1gene of mtDNA presented here may be valuable when only a limited amount of material is available for the molecular species diagnosis of O. stephanostomum.

Species composition of Necator hookworms was surveyed in (i) Ugandan chimpanzees living around farms and villages at Bulindi, (ii) Gabonese gorillas under habituation in Moukalaba-Doudou National Park (MDNP), and (iii) Gabonese villagers living adjacent to MDNP. Internal transcribed spacers (ITS) of rDNA and partial cytochrome c oxidase subunit 1 (Cox1) gene of mtDNA were analyzed from larvae obtained by coproculture. Three ITS types (I, II and III) and three Cox1 haplotype groups (A, B and C) were demonstrated. ITS type I and Cox1 haplotype group A, representing Necator americanus, were demonstrated in the hookworm larvae from Gabonese gorillas and humans, but not from Ugandan chimpanzees. Type II and haplotype groups B and C, presumably representing N. gorillae, were found in larvae from Ugandan chimpanzees and Gabonese gorillas and humans. These features were overall similar with those found previously in the Central African Republic. Meanwhile, type III was proven in a larva from a Gabonese gorilla as the first demonstration from a non-human primate. Cox1 haplotypes obtained from Ugandan chimpanzees formed a subgroup within group B, presumably reflecting dispersal and diversification processes of the apes.

The gullet worm (Gongylonema pulchrum) has been recorded from a variety of mammals worldwide, including monkeys and humans. Due to its wide host range, it has been suggested that the worm may be transmitted locally to any mammalian host by chance. To investigate this notion, the ribosomal RNA gene (rDNA), mainly regions of the internal transcribed spacers (ITS) 1 and 2, and a cytochrome c oxidase subunit I (COI) region of mitochondrial DNA of G. pulchrum were characterized using parasites from the following hosts located in Japan: cattle, sika deer, wild boars, Japanese macaques, a feral Reeves's muntjac and captive squirrel monkeys. The rDNA nucleotide sequences of G. pulchrum were generally well conserved regardless of their host origin. However, a few insertions/deletions of nucleotides along with a few base substitutions in the ITS1 and ITS2 regions were observed in G. pulchrum from sika deer, wild boars and Japanese macaques, and those differed from G. pulchrum in cattle, the feral Reeves's muntjac and captive squirrel monkeys. The COI sequences of G. pulchrum were further divided into multiple haplotypes and two groups of haplotypes, i.e. those from a majority of sika deer, wild boars and Japanese macaques and those from cattle and zoo animals, were clearly differentiated. Our findings indicate that domestic and sylvatic transmission cycles of the gullet worm are currently present, at least in Japan.

Similar to wild mammals on the continents, mange caused by the mange mite, Sarcoptes scabiei (Acari: Sarcoptidae) is spreading in wild mammals in most of Japan. We collected crusted or alopetic skin from 120 raccoon dogs (Nyctereutes procyonoides viverrinus), three raccoons (Procyon lotor), six Japanese badgers (Meles anakuma), one Japanese marten (Martes melampus), one stray dog (Canis lupus familiaris), four wild boars (Sus scrofa leucomystax), and one Japanese serow (Capricornis crispus), mainly in an area where mangy wild animals have been increasingly noted in the past 4 yr. The second internal transcribed spacer (ITS2) region of the ribosomal RNA gene and the partial 16S and cytochrome c oxidase subunit I (cox-1) genes of mitochondrial DNA (mtDNA) were characterized in these skin samples. The ITS2 sequencing (404 base pairs [bp]) identified the causative mite for mangy skin lesions of 128 animals as S. scabiei, regardless of host origin. The cat mite (Notoedres cati) was the cause in one raccoon dog and one raccoon. Most mites had almost identical ITS2 nucleotide sequences to those recorded in a variety of mammals worldwide. Partial 16S and cox-1 fragments of mtDNA amplified and sequenced successfully (331 bp and 410 bp, respectively) showed an identical nucleotide sequence except for one site (C vs. T) for the former and four sites (G, C, C, C vs. A, T, T, T, respectively) for the latter fragment. These substitutions were always synchronized, with the two mitochondrial DNA haplotypes (i.e., C/GCCC and T/ATTT) appearing to separately colonize in geographic units. The T/ATTT haplotype fell into a clade where animal-derived mites worldwide dominated, whereas the C/GCCC haplotype formed a geographic branch unique to Japanese isolates. These results suggest that heterologous populations of monospecific S. scabiei are expanding their populations and distributions regardless of host species in an apparently local mange epizootic of wild mammals in Japan.

AbSTRACT. The northern snakehead Channa argus, native to China, Russia and Korea, is currently found widespread throughout Japan following its original introduction during the 1920s. A parasitological study of 10 snakeheads fished from the Fushinogawa River running through Yamaguchi City, Japan, detected 2-101 (average, 23.7) metacercariae per 100 g of trunk muscle from each fish. The trematode was identified as metacercariae of Posthodiplostomum sp. (Strigeidida: Diplostomidae) morphologically and characterized genetically based on the ribosomal RNA gene (rDNA). Phylogenetic trees were constructed on the basis of either the 18S, ITS or 28S region of rDNA to assess the relationship among members of the family Diplostomidae. The addition of genetic data from more diplostomid taxa, particularly Posthodiplostomum cuticola recorded from a variety of freshwater fish in Eurasia, would facilitate the precise identification of the present species.