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  1. Fulltext Description, molecular characteristics and Wolbachia endosymbionts of Onchocerca borneensis Uni, Mat Udin & Takaoka n. sp. (Nematoda: Filarioidea) from the Bornean bearded pig Sus barbatus Müller (Cetartiodactyla: Suidae) of Sarawak, Malaysia
    Uni S, Mat Udin AS, Agatsuma T, Junker K, Saijuntha W, Bunchom N, et al.
    Parasit Vectors, 2020 Feb 06;13(1):50.
    PMID: 32028994 DOI: 10.1186/s13071-020-3907-8
    BACKGROUND: The genus Onchocerca Diesing, 1841 includes species of medical importance, such as O. volvulus (Leuckart, 1893), which causes river blindness in the tropics. Recently, zoonotic onchocercosis has been reported in humans worldwide. In Japan, O. dewittei japonica Uni, Bain & Takaoka, 2001 from wild boars is a causative agent for this zoonosis. Many filarioid nematodes are infected with Wolbachia endosymbionts which exhibit various evolutionary relationships with their hosts. While investigating the filarial fauna of Borneo, we discovered an undescribed Onchocerca species in the bearded pig Sus barbatus Müller (Cetartiodactyla: Suidae).

    METHODS: We isolated Onchocerca specimens from bearded pigs and examined their morphology. For comparative material, we collected fresh specimens of O. d. dewittei Bain, Ramachandran, Petter & Mak, 1977 from banded pigs (S. scrofa vittatus Boie) in Peninsular Malaysia. Partial sequences of three different genes (two mitochondrial genes, cox1 and 12S rRNA, and one nuclear ITS region) of these filarioids were analysed. By multi-locus sequence analyses based on six genes (16S rDNA, ftsZ, dnaA, coxA, fbpA and gatB) of Wolbachia, we determined the supergroups in the specimens from bearded pigs and those of O. d. dewittei.

    RESULTS: Onchocerca borneensis Uni, Mat Udin & Takaoka n. sp. is described on the basis of morphological characteristics and its genetic divergence from congeners. Molecular characteristics of the new species revealed its close evolutionary relationship with O. d. dewittei. Calculated p-distance for the cox1 gene sequences between O. borneensis n. sp. and O. d. dewittei was 5.9%, while that between O. d. dewittei and O. d. japonica was 7.6%. No intraspecific genetic variation was found for the new species. Wolbachia strains identified in the new species and O. d. dewittei belonged to supergroup C and are closely related.

    CONCLUSIONS: Our molecular analyses of filarioids from Asian suids indicate that the new species is sister to O. d. dewittei. On the basis of its morphological and molecular characteristics, we propose to elevate O. d. japonica to species level as O. japonica Uni, Bain & Takaoka, 2001. Coevolutionary relationships exist between the Wolbachia strains and their filarial hosts in Borneo and Peninsular Malaysia.

    Matched MeSH terms: Onchocerciasis/transmission; Onchocerciasis/veterinary*; Onchocerciasis, Ocular/parasitology; Onchocerciasis, Ocular/transmission
  2. 15 years of APOC--a lifetime of public health evidence
    Allotey P, Amazigo U, Adjei S, Seddoh A, Lusamba-Dikassa PS
    Lancet, 2012 Oct 20;380(9851):1361-3.
    PMID: 23084441 DOI: 10.1016/S0140-6736(12)60723-5
    Matched MeSH terms: Onchocerciasis, Ocular/drug therapy; Onchocerciasis, Ocular/epidemiology; Onchocerciasis, Ocular/prevention & control*
  3. Prevalence of Onchocerca japonica and O. takaokai infections in the Japanese wild boar, Sus scrofa leucomystax, and the Ryukyu wild boar, S. s. riukiuanus, in Japan
    Uni S, Fukuda M, Uga S, Agatsuma T, Nakatani J, Suzuki K, et al.
    Parasitol Int, 2021 Aug;83:102313.
    PMID: 33662527 DOI: 10.1016/j.parint.2021.102313
    Reports of zoonotic infections with Onchocerca japonica (Nematoda: Filarioidea), which parasitizes the Japanese wild boar, Sus scrofa leucomystax, have recently increased in Japan. To predict the occurrence of infection in humans, it is necessary to determine the prevalence of O. japonica infection in the natural host animals. We investigated the presence of adult worms in the footpads, and of microfilariae in skin snips, taken from the host animals, between 2000 and 2018. Onchocerca japonica was found in 165 of 223 (74%) Japanese wild boars in Honshu and Kyushu. Among the nine regions studied, the highest prevalence of O. japonica infection was found in Oita, Kyushu, where 47 of 52 (90.4%) animals were infected. The ears were the predilection sites for O. japonica microfilariae. Adult worms of O. japonica were found more frequently in the hindlimbs than in the forelimbs of the host animals. Onchocerca takaokai was found in 14 of 52 (26.9%) Japanese wild boars in Oita. In Kakeroma Island among the Nansei Islands, both O. japonica and O. takaokai were isolated from the Ryukyu wild boar, S. s. riukiuanus. These observations could help predict future occurrences of human zoonotic onchocercosis in Japan.
    Matched MeSH terms: Onchocerciasis/epidemiology; Onchocerciasis/parasitology; Onchocerciasis/veterinary*
  4. Fulltext Predicting the environmental suitability for onchocerciasis in Africa as an aid to elimination planning
    Cromwell EA, Osborne JCP, Unnasch TR, Basáñez MG, Gass KM, Barbre KA, et al.
    PLoS Negl Trop Dis, 2021 07;15(7):e0008824.
    PMID: 34319976 DOI: 10.1371/journal.pntd.0008824
    Recent evidence suggests that, in some foci, elimination of onchocerciasis from Africa may be feasible with mass drug administration (MDA) of ivermectin. To achieve continental elimination of transmission, mapping surveys will need to be conducted across all implementation units (IUs) for which endemicity status is currently unknown. Using boosted regression tree models with optimised hyperparameter selection, we estimated environmental suitability for onchocerciasis at the 5 × 5-km resolution across Africa. In order to classify IUs that include locations that are environmentally suitable, we used receiver operating characteristic (ROC) analysis to identify an optimal threshold for suitability concordant with locations where onchocerciasis has been previously detected. This threshold value was then used to classify IUs (more suitable or less suitable) based on the location within the IU with the largest mean prediction. Mean estimates of environmental suitability suggest large areas across West and Central Africa, as well as focal areas of East Africa, are suitable for onchocerciasis transmission, consistent with the presence of current control and elimination of transmission efforts. The ROC analysis identified a mean environmental suitability index of 0·71 as a threshold to classify based on the location with the largest mean prediction within the IU. Of the IUs considered for mapping surveys, 50·2% exceed this threshold for suitability in at least one 5 × 5-km location. The formidable scale of data collection required to map onchocerciasis endemicity across the African continent presents an opportunity to use spatial data to identify areas likely to be suitable for onchocerciasis transmission. National onchocerciasis elimination programmes may wish to consider prioritising these IUs for mapping surveys as human resources, laboratory capacity, and programmatic schedules may constrain survey implementation, and possibly delaying MDA initiation in areas that would ultimately qualify.
    Matched MeSH terms: Onchocerciasis/drug therapy; Onchocerciasis/epidemiology*; Onchocerciasis/transmission
  5. A new case of zoonotic onchocercosis in northern Kyushu, Japan
    Fukuda M, Uni S, Otsuka Y, Eshita Y, Nakatani J, Ihara K, et al.
    Parasitol Int, 2015 Dec;64(6):519-21.
    PMID: 26209456 DOI: 10.1016/j.parint.2015.07.006
    A case of zoonotic onchocercosis has been found in a resident who lived in Iizuka City, Fukuoka Prefecture, Japan for some time. A 24-year-old male developed a painful nodule on the middle finger of his right hand. The nodule was surgically removed from the vagina fibrosa tendinis of the finger at Beppu Medical Center, Beppu City, Oita Prefecture in 2012. The causative agent was identified as a female Onchocerca dewittei japonica based on its histopathological characteristics. The identity of the filarioid has been confirmed by sequencing the cox1 gene. The present study indicates that the zoonotic onchocercosis caused by O. dewittei japonica has been concentrated in northeast Kyushu.
    Matched MeSH terms: Onchocerciasis
  6. Zoonotic infection with Onchocerca dewittei japonica in an 11-year-old boy in Kansai Region, Western Honshu, Japan
    Uni S, Fukuda M, Ogawa K, Lim YA, Agatsuma T, Bunchom N, et al.
    Parasitol Int, 2017 Oct;66(5):593-595.
    PMID: 28648713 DOI: 10.1016/j.parint.2017.06.006
    An 11-year-old boy living in Otsu City, Shiga Prefecture, Kansai Region, Western Honshu, Japan had zoonotic onchocercosis. The patient developed a painful swelling on the little finger of his left hand. The worm detected in the excised mass had external transverse ridges but did not have inner striae in the cuticle. On the basis of the parasite's histopathological characteristics, the causative agent was identified as a female Onchocerca dewittei japonica (Spirurida: Onchocercidae). The species of the filarial parasite was confirmed by sequencing the cox1 gene of the parasite. The Japanese wild boar Sus scrofa leucomystax is a definitive host for O. dewittei japonica, which is then transmitted by blackflies as the vector to humans. The current case described occurred in the Kansai Region, Western Honshu, where such infections were previously not reported.
    Matched MeSH terms: Onchocerciasis/diagnosis*; Onchocerciasis/parasitology*; Onchocerciasis/veterinary
  7. Onchocerca dewittei japonica n. subsp., a common parasite from wild boar in Kyushu Island, Japan
    Uni S, Bain O, Takaoka H, Miyashita M, Suzuki Y
    Parasite, 2001 Sep;8(3):215-22.
    PMID: 11584751
    We describe Onchocerca dewittei japonica n. subsp. from the Japanese wild boar, Sus scrofa leucomystax, in Oita, Kyushu Island, where all seven animals examined were found to be infected. This study began with efforts to identify the causative species in a recent case of zoonotic onchocerciasis. Compared with Onchocerca dewittei dewittei from Sus scrofa jubatus in Malaysia, which was reexamined here, our new subspecies has much greater space between the ridges on the females. In addition, its microfilariae (from uteri) are shorter (192-210 microns compared with 228-247 microns), and only the posterior third of the microfilarial body is coiled, instead of the entire body. The Onchocerca species parasitic in suids (these two subspecies and O. ramachandrini from the warthog in the Ethiopian region) form a group sharing several characters. Among the most unusual characters are the body swellings (a specialized apparatus for mating, known in only a few other genera). In addition, longitudinal cuticular crests were found on males of both subspecies from wild boar and on females of O. ramachandrini.
    Matched MeSH terms: Onchocerciasis/parasitology; Onchocerciasis/veterinary
  8. Status of Onchocerca volvulus infection and transmission by blackflies after 15 years of ivermectin distribution at Adani, Nigeria
    Onah IE, Ubachukwu PO, Eyo JE
    Trop Biomed, 2020 Mar 01;37(1):174-185.
    PMID: 33612728
    The nuisance bites of blackflies and transmission of Onchocerca volvulus, which causes onchocerciasis, constitutes a threat to public health and an impediment to food production in rural and riverine communities in Nigeria. The entomological profile of onchocerciasis at Adani, Nigeria, was investigated from August 2010 to January 2011 to determine the transmission of O. volvulus after 15 years of ivermectin distribution in the area. A total of 548 adult female blackflies of the Simulium damnosum complex were caught using human baits and dissected. Of this number, 248 flies were caught in the wet season (August to October), while 300 flies were caught in the dry season (November to January). The relative abundance of flies at Adani varied from 21 in December to 243 in January. The monthly catches between September and October and between December and January were significantly different. The monthly population density of the flies ranged from 0.5Flies/Man/Hour (FMH) in December to 5.5FMH in January. The diurnal biting pattern of the S. damnosum complex at the site showed a bimodal peak of activity with the evening peak being higher than the morning peak except in October when the morning peak was higher than the evening peak. The morning peaks were observed between 7.00 am and 10.00 am, whereas the evening peaks occurred between 4.00 pm and 6.00 pm. The morning and evening biting peaks in all the months were not significantly different. Nulliparous flies accounted for 75.7% of the total catch, whereas 24.3% of the flies caught were parous. The infection, infective bites and transmission of O. volvulus during the study period were zero. This study suggests that transmission of O. volvulus has been halted and the flies are presently more nuisance biters than disease vectors since no stage of O. volvulus was found in the flies dissected.
    Matched MeSH terms: Onchocerciasis/epidemiology*; Onchocerciasis/transmission*
  9. Blackfly vectors of zoonotic onchocerciasis in Japan
    Takaoka H, Fukuda M, Otsuka Y, Aoki C, Uni S, Bain O
    Med Vet Entomol, 2012 Dec;26(4):372-8.
    PMID: 22827756 DOI: 10.1111/j.1365-2915.2012.01023.x
    Studies of blackfly vectors of Onchocerca dewittei japonica Uni, Bain & Takaoka (Spirurida: Onchocercidae), a parasite of wild boar implicated in the aetiology of zoonotic onchocerciasis in Japan, and six other zoonotic Onchocerca species of this country are reviewed. Molecular identification of infective larvae found in wild-caught female blackflies showed that Simulium bidentatum (Shiraki) (Diptera: Simuliidae) is a natural vector of O. dewittei japonica, and also Onchocerca sp. sensu Fukuda et al., another parasite of wild boar. Inoculation experiments demonstrated that Simulium arakawae Matsumura and four other Simulium species are putative vectors. Similarly, S. arakawae, S. bidentatum and Simulium oitanum (Shiraki) are putative vectors of Onchocerca eberhardi Uni & Bain and Onchocerca skrjabini Rukhlyadev, parasites of sika deer. Morphometric studies of infective larvae indicated that Onchocerca lienalis Stiles, a bovine species, is transmitted by S. arakawae, Simulium daisense (Takahasi) and Simulium kyushuense Takaoka, and that Onchocerca sp. sensu Takaoka & Bain, another bovine species, is transmitted by S. arakawae, S. bidentatum, S. daisense and S. oitanum. Prosimulium sp. (Diptera: Simuliidae) and Simulium japonicum Matsumura are suspected vectors of Onchocerca suzukii Yagi, Bain & Shoho and O. skrjabini [Twinnia japonensis Rubtsov (Diptera: Simuliidae) may also transmit the latter], parasites of Japanese serow, following detection of the parasites' DNA genes in wild-caught blackflies.
    Matched MeSH terms: Onchocerciasis/parasitology; Onchocerciasis/transmission*
  10. Fulltext New zoonotic cases of Onchocerca dewittei japonica (Nematoda: Onchocercidae) in Honshu, Japan
    Uni S, Fukuda M, Otsuka Y, Hiramatsu N, Yokobayashi K, Takahashi H, et al.
    Parasit Vectors, 2015;8:59.
    PMID: 25623081 DOI: 10.1186/s13071-015-0655-2
    Zoonotic infections with Onchocerca species are uncommon, and to date only 25 clinical cases have been reported worldwide. In Japan, five previous zoonotic infections were concentrated in Oita, Kyushu (the southern island), with one previous case in Hiroshima in the western part of Honshu (the main island). The causative agent in Japan was identified as Onchocerca dewittei japonica Uni, Bain & Takaoka, 2001 from Japanese wild boars (Sus scrofa leucomystax Temminck, 1842). Here we report two infections caused by a female and male O. dewittei japonica, respectively, among residents of Hiroshima and Shimane Prefectures in the western part of Honshu.
    Matched MeSH terms: Onchocerciasis/parasitology*; Onchocerciasis/transmission
  11. Fulltext Anti-Wolbachia therapy for onchocerciasis & lymphatic filariasis: Current perspectives
    Wan Sulaiman WA, Kamtchum-Tatuene J, Mohamed MH, Ramachandran V, Ching SM, Sazlly Lim SM, et al.
    Indian J Med Res, 2019 06;149(6):706-714.
    PMID: 31496523 DOI: 10.4103/ijmr.IJMR_454_17
    Onchocerciasis and lymphatic filariasis (LF) are human filarial diseases belonging to the group of neglected tropical diseases, leading to permanent and long-term disability in infected individuals in the endemic countries such as Africa and India. Microfilaricidal drugs such as ivermectin and albendazole have been used as the standard therapy in filariasis, although their efficacy in eliminating the diseases is not fully established. Anti-Wolbachia therapy employs antibiotics and is a promising approach showing potent macrofilaricidal activity and also prevents embryogenesis. This has translated to clinical benefits resulting in successful eradication of microfilarial burden, thus averting the risk of adverse events from target species as well as those due to co-infection with loiasis. Doxycycline shows potential as an anti-Wolbachia treatment, leading to the death of adult parasitic worms. It is readily available, cheap and safe to use in adult non-pregnant patients. Besides doxycycline, several other potential antibiotics are also being investigated for the treatment of LF and onchocerciasis. This review aims to discuss and summarise recent developments in the use of anti-Wolbachia drugs to treat onchocerciasis and LF.
    Matched MeSH terms: Onchocerciasis/drug therapy*; Onchocerciasis/microbiology; Onchocerciasis/epidemiology
  12. Fulltext Building country capacity to sustain NTD programs and progress: A call to action
    Sodahlon Y, Ross DA, McPhillips-Tangum C, Lawrence J, Taylor R, McFarland DA, et al.
    PLoS Negl Trop Dis, 2020 10;14(10):e0008565.
    PMID: 33031387 DOI: 10.1371/journal.pntd.0008565
    Matched MeSH terms: Onchocerciasis/drug therapy
  13. Genetic diversity and DNA barcoding of the black fly (Diptera: Simuliidae) vectors of parasites causing human onchocerciasis in Guatemala
    Pramual P, Bunchom N, Saijuntha W, Tada I, Suganuma N, Agatsuma T
    Trop Biomed, 2019 Dec 01;36(4):938-957.
    PMID: 33597465
    Genetic variation based on mitochondrial cytochrome c oxidase I (COI) and II (COII) sequences was investigated for three black fly nominal species, Simulium metallicum Bellardi complex, S. callidum Dyar and Shannon, and S. ochraceum Walker complex, which are vectors of human onchocerciasis from Guatemala. High levels of genetic diversity were found in S. metallicum complex and S. ochraceum complex with maximum intraspecific genetic divergences of 11.39% and 4.25%, respectively. Levels of genetic diversity of these nominal species are consistent with species status for both of them as they are cytologically complexes of species. Phylogenetic analyses revealed that the S. metallicum complex from Guatemala divided into three distinct clades, two with members of this species from several Central and South American countries and another exclusively from Mexico. The Simulium ochraceum complex from Guatemala formed a clade with members of this species from Mexico and Costa Rica while those from Ecuador and Colombia formed another distinct clade. Very low diversity in S. callidum was found for both genes with maximum intraspecific genetic divergence of 0.68% for COI and 0.88% for COII. Low genetic diversity in S. callidum might be a consequence of the result being informative of only recent population history of the species.
    Matched MeSH terms: Onchocerciasis/transmission
  14. Opisthorchis viverrini (Poirier, 1886) a trematode parasite of man in West Malaysia
    Bisseru B, Chong LK
    Trop Geogr Med, 1969 Jun;21(2):138-46.
    PMID: 5816416
    Matched MeSH terms: Onchocerciasis/drug therapy
  15. Onchocerca takaokai n. sp. (Nematoda: Filarioidea) in Japanese wild boars (Sus scrofa leucomystax): Description and molecular identification of intradermal females
    Uni S, Fukuda M, Agatsuma T, Bain O, Otsuka Y, Nakatani J, et al.
    Parasitol Int, 2015 Dec;64(6):493-502.
    PMID: 26165205 DOI: 10.1016/j.parint.2015.07.001
    Human zoonotic onchocercosis is caused by Onchocerca dewittei japonica, parasitic in wild boars (Sus scrofa leucomystax) in Japan. Previously, microfilariae longer than those of Onchocerca dewittei japonica were observed in skin snips from wild boars during the study of O. dewittei japonica. Moreover, the third-stage larvae (L3) of these longer microfilariae were obtained from the blackfly Simulium bidentatum after experimental injections. Based on morphometric and molecular studies, similar L3 were found in blackflies during fieldwork in Oita, Japan. However, except for O. dewittei japonica, adult worms of Onchocerca have not been found in wild boars. In this study, we discovered adult females of a novel Onchocerca species in the skin of a wild boar in Oita, and named it Onchocerca takaokai n. sp. Females of this new species had longer microfilariae and differed from O. dewittei japonica in terms of their morphological characteristics and parasitic location. The molecular characteristics of the cytochrome c oxidase subunit 1 and 12S rRNA genes of the new species were identical to those of the longer microfilariae and L3 previously detected, but they differed from those of O. dewittei japonica at the species level. However, both species indicated a close affinity among their congeners and Onchocerca ramachandrini, parasitic in the warthog in Africa, was basal in the Suidae cluster of the 12S rRNA tree.
    Matched MeSH terms: Onchocerciasis
  16. Fulltext Seasonal Filarial Infections and Their Black Fly Vectors in Chiang Mai Province, Northern Thailand
    Aupalee K, Saeung A, Srisuka W, Fukuda M, Streit A, Takaoka H
    Pathogens, 2020 Jun 25;9(6).
    PMID: 32630410 DOI: 10.3390/pathogens9060512
    The transmission of zoonotic filarial parasites by black flies has so far been reported in the Chiang Mai and Tak provinces, Thailand, and the bites of these infected black flies can cause a rare disease-human zoonotic onchocerciasis. However, species identification of the filarial parasites and their black fly vectors in the Chiang Mai province were previously only based on a morphotaxonomic analysis. In this study, a combined approach of morphotaxonomic and molecular analyses (mitochondrial cox1, 12S rRNA, and nuclear 18S rRNA (SSU HVR-I) genes) was used to clarify the natural filarial infections in female black flies collected by using human and swine baits from two study areas (Ban Lek and Ban Pang Dang) in the Chiang Mai province from March 2018 to January 2019. A total of 805 and 4597 adult females, belonging to seven and nine black fly taxa, were collected from Ban Lek and Ban Pang Dang, respectively. At Ban Lek, four of the 309 adult females of Simulium nigrogilvum were positive for Onchocerca species type I in the hot and rainy seasons. At Ban Pang Dang, five unknown filarial larvae (belonging to the same new species) were detected in Simulium sp. in the S. varicorne species-group and in three species in the S. asakoae species-group in all seasons, and three non-filarial larvae of three different taxa were also found in three females of the S. asakoae species-group. This study is the first to molecularly identify new filarial species and their vector black fly species in Thailand.
    Matched MeSH terms: Onchocerciasis
  17. Fulltext Anti-nematode activity of sixteen compounds against Trichinella spiralis in mice--a possible new screen for macrofilaricides
    Surin J
    Southeast Asian J. Trop. Med. Public Health, 1995 Mar;26(1):128-34.
    PMID: 8525399
    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.
    Matched MeSH terms: Onchocerciasis/drug therapy
  18. Multicentre laboratory evaluation of Brugia Rapid dipstick test for detection of brugian filariasis
    Rahmah N, Shenoy RK, Nutman TB, Weiss N, Gilmour K, Maizels RM, et al.
    Trop Med Int Health, 2003 Oct;8(10):895-900.
    PMID: 14516300
    A multicentre evaluation of the Brugia Rapid dipstick test was performed using 1263 serum samples in four international laboratories, i.e. T.D. Medical College (TDMC, India), National Institutes of Health (NIH, USA), Swiss Tropical Institute (STI, Switzerland) and Leiden University Medical Centre (LUMC, Netherlands). In comparison with microscopy, the dipstick demonstrated sensitivities of 97.2% (70 of 72) at TDMC, 91.6% (175 of 191) at LUMC and 100% (six of six) at STI. Sera of chronic patients showed a positivity rate of 11.3% (19 of 168) and 61.2% (71of 116) at TDMC and LUMC, respectively. All 266 sera of non-endemic normals from STI, NIH and LUMC tested negative with the dipstick. At LUMC, sera of 'endemic normals' (amicrofilaraemics with no clinical disease) from an area with approximately 35% microfilaria positivity showed 60.8% positive results (31 of 51), thus demonstrating the likelihood of many cryptic infections occurring in this population. Specificities of the test with Onchocerca volvulus sera were 98.8% (80 of 81) and 100% (10 of 10) at the NIH and STI, respectively; while specificity with Loa loa sera at the NIH was 84.6% (44 of 52). At the STI, the dipstick test also demonstrated 100% specificity when tested with 75 sera from various protozoan and helminthic infections.
    Matched MeSH terms: Onchocerciasis/diagnosis
  19. Human case of Onchocerca dewittei japonica infection in Fukushima, Northeastern Honshu, Japan
    Fukuda M, Uni S, Igari T, Utsumi Y, Otsuka Y, Nakatani J, et al.
    Parasitol Int, 2019 Oct;72:101943.
    PMID: 31220633 DOI: 10.1016/j.parint.2019.101943
    A 73-year-old man living in Kawamata-machi, Fukushima Prefecture, Northeastern Honshu, Japan, visited a hospital with complaints of a subcutaneous swelling that had developed on the back of his left hand. The nodule was surgically removed from the vagina fibrosa tendinis of his left forefinger. Based on the histopathological characteristics, the causative agent of this nodule was identified as a female Onchocerca dewittei japonica (Spirurida: Onchocercidae). The species identification was confirmed by cox1 gene sequencing of the worm tissues from paraffin-embedded sections of the nodule. Although 11 cases of zoonotic onchocercosis have previously been recorded in Kyushu and Western Honshu, Japan, the present findings represent the first human case of infection with O. dewittei japonica in Northeastern Honshu, Japan.
    Matched MeSH terms: Onchocerciasis/diagnosis*
  20. Natural infections with larvae of Onchocerca species type I in the human-biting black fly, Simulium nigrogilvum (Diptera: Simuliidae), in western Thailand
    Saeung A, Srisuka W, Aupalee K, Fukuda M, Otsuka Y, Taai K, et al.
    Acta Trop, 2020 Apr;204:105344.
    PMID: 31954685 DOI: 10.1016/j.actatropica.2020.105344
    Zoonotic onchocerciasis is a human infection caused by Onchocerca species of animal origins and transmitted by black fly vectors. The reported incidence of this disease has increased throughout the world. This study aims to clarify the vectorial roles of black fly species in zoonotic filarial transmission in Tak province, western Thailand. The integrated approach of morphological and DNA sequence-based analyses was used to identify species of both wild-caught female black flies and infective filarial larvae found in the infected black flies. All of 494 female black flies captured were identified as Simulium nigrogilvum, through scanning electron microscopy (SEM) and DNA sequence analyses based on the cytochrome c oxidase subunit I (COI) and subunit II (COII), and the fast-evolving nuclear elongation complex protein 1 (ECP1) genes. Four females of S. nigrogilvum harbored one to three third-stage larvae (infective larvae) in their thoraces, with an infection rate of 0.81% (4/494). All infective larvae were similar in morphology and size to one another, being identified as Onchocerca species type I (= O. sp. type A), a bovine filaria, originally reported from Japan, and also as O. sp. found in S. nodosum in Thailand, based on their body lengths and widths being 1,068-1,346 µm long by 25-28 µm wide, and morphological characters. Comparisons of cytochrome c oxidase subunit I (COI) and 12S rRNA sequences of mitochondrial DNA (mtDNA) and phylogenetic analyses with those of previous reports strongly supported that all larvae were O. sp. type I. This report is the first indicating the presence of O. sp. type I in Thailand and its vector being S. nigrogilvum.
    Matched MeSH terms: Onchocerciasis
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