Savannakhét, Laos
Savannakhét, Laos

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Sato M.O.,Federal University of Tocantins | Sato M.,Niigata University | Chaisiri K.,Mahidol University | Maipanich W.,Mahidol University | And 6 more authors.
Revista Brasileira de Parasitologia Veterinaria | Year: 2014

Trichostrongylids infection has gained significant public health importance since Trichostrongylus spp. infections have been reported in humans in Lao PDR. In this study, gastrointestinal nematodes were identified and the intensity of infections was determined in goats and cattle, which are animals greatly used for meat production in Lahanam Village, Lao PDR. The total number of goats and bovines was 23 and 29, respectively, pertaining to 32 households surveyed in the area. Feacal samples were randomly collected from 14 goats and 11 bovines. Ninety three percent (13/14) of goats and 36% (3/11) of cattle were infected, with an average of 1,728 and 86 eggs per gram of faeces (EPG), respectively. Coproculture showed Trichostrongylus spp. (goats 16%; bovines 48%), Haemonchus spp. (goats 69%; bovines 37%), Cooperia spp. (bovines 8%) and Oesophagostomum spp. (goats 15%; bovines 6%). After performing the necropsy on an adult goat, Trichuris spp. was also found. We confirmed the presence of Oesophagostomum spp., H. contortus and T. colubriformis by morphology and DNA sequencing analysis of the ITS region of rDNA. Due to interactions between humans and goats in Lahanam Village and high EPG results, the diagnosis of species and the intensity of gastrointestinal nematode infection in these animals are important public-health issues. Other ruminant parasites, such as Oesophagostomum and Haemonchus, found in caprines and bovines, are reported to be causes of zoonosis and their presence in humans should be investigated in future field surveys in this area.


Tomokawa S.,Shinshu University | Kobayashi T.,Hiroshima University | Pongvongsa T.,Station of Malariology | Nisaygnang B.,National Institute of Public Health | And 4 more authors.
Southeast Asian Journal of Tropical Medicine and Public Health | Year: 2012

A matched-pair case-control study was conducted to identify factors associated with Opisthorchis viverrini infection among primary schoolchildren to develop preventive education. A house-to-house interview of the guardians of 118 children (59 cases and 59 controls) was conducted to collect information about theirs and their children's fish eating habits of 10 locally available fish species. The guardians' knowledge and attitudes about Opisthorchis viverrini infection and socio-economic status were asked about. The frequencies of eating fish did not differ between cases and controls. However, cases ate raw fish more frequently than controls (5.1 vs 1.2 times monthly). The frequency of eating raw "pa-xiew" was most strongly related to infection (OR 2.47; 95%CI 1.05-5.82). Infection was significantly associated with the children's experiences of eating raw fish (OR 7.48; 95% CI 1.45-38.69), frequency of eating raw fish by their guardians (OR 1.26; 95% CI 1.04-1.53) and maternal educational and career (OR 0.76; 95% CI 0.62-0.94). To prevent infections it is necessary to prevent the fish from becoming infected and to avoid eating raw fish. Education should focus on the children and their guardians to promote better eating habits.


Sanguankiat S.,Mahidol University | Sato M.O.,Dokkyo Medical University | Sato M.O.,Federal University of Tocantins | Sato M.,Niigata University | And 7 more authors.
Korean Journal of Parasitology | Year: 2016

In the present study, we report on the occurrence of paramphistomes, Fischoederius cobboldi and Paramphistomum epiclitum, in Lao PDR with the basis of molecular data. Parasite materials were collected from bovines bred in Ban Lahanam area, Savannakhet Province, Lao PDR at Lahanam public market. Morphological observations indicated 2 different species of paramphistomes. The mitochondrial gene cox1 of the specimens was successfully amplified by PCR and DNA sequencing was carried out for diagnosis of 11 specimens. Pairwise alignment of cox1 sequences were performed and confirmed F. cobboldi and P. epiclitum infecting bovines in Laos. Although there were many limiting points, as the small number of worm samples, and the restricted access of the animal host materials, we confirmed for the first time that 2 species of paramphistomes, F. cobboldi and P. epiclitum, are distributed in Lao PDR. More studies are needed to confirm the paramphistome species present in Savannakhet and its hosts to clear the natural history of these parasites of ruminants in the region and measure the impact of this parasite infection in the life and health of the local people. © 2016, Korean Society for Parasitology and Tropical Medicine.


Otake M.O.,Federal University of Tocantins | Sato M.,Niigata University | Chaisiri K.,Mahidol University | Maipanich W.,Mahidol University | And 6 more authors.
Revista brasileira de parasitologia veterinária = Brazilian journal of veterinary parasitology : Órgão Oficial do Colégio Brasileiro de Parasitologia Veterinária | Year: 2014

Trichostrongylids infection has gained significant public health importance since Trichostrongylus spp. infections have been reported in humans in Lao PDR. In this study, gastrointestinal nematodes were identified and the intensity of infections was determined in goats and cattle, which are animals greatly used for meat production in Lahanam Village, Lao PDR. The total number of goats and bovines was 23 and 29, respectively, pertaining to 32 households surveyed in the area. Feacal samples were randomly collected from 14 goats and 11 bovines. Ninety three percent (13/14) of goats and 36% (3/11) of cattle were infected, with an average of 1,728 and 86 eggs per gram of faeces (EPG), respectively. Coproculture showed Trichostrongylus spp. (goats 16%; bovines 48%), Haemonchus spp. (goats 69%; bovines 37%), Cooperia spp. (bovines 8%) and Oesophagostomum spp. (goats 15%; bovines 6%). After performing the necropsy on an adult goat, Trichuris spp. was also found. We confirmed the presence of Oesophagostomum spp., H. contortus and T. colubriformis by morphology and DNA sequencing analysis of the ITS region of rDNA. Due to interactions between humans and goats in Lahanam Village and high EPG results, the diagnosis of species and the intensity of gastrointestinal nematode infection in these animals are important public-health issues. Other ruminant parasites, such as Oesophagostomum and Haemonchus, found in caprines and bovines, are reported to be causes of zoonosis and their presence in humans should be investigated in future field surveys in this area.


Sato M.,Federal University of Tocantins | Yoonuan T.,Mahidol University | Sanguankiat S.,Mahidol University | Nuamtanong S.,Mahidol University | And 6 more authors.
American Journal of Tropical Medicine and Hygiene | Year: 2011

In Lahanam Village, Savannakhet Province, Laos, 125 of 253 villagers (49.4%) were found by fecal examination to harbor hookworm eggs. The eggs were heterogeneous in morphology and size, suggesting infections of mixed nematode species. To confirm the hookworm egg species, on a voluntary basis, 46 hookworm egg-positive participants were treated with albendazole, and post-treatment adult worms were collected from purged fecal samples. The common human hookworm was found in only 3 participants; 1 case of Necator americanus, and 2 cases of Ancylostoma duodenale. In contrast, adult Trichostrongylus worms were expelled from most participants (43 of 46, 93.5%). The Trichostrongylus species were confirmed by morphology and internal transcribed spacer 2 sequences; all worms were of the same species (T. colubriformis). In addition, some Trichostrongylus worms were obtained from a goat in the same village and identified as T. colubriformis. The results suggested that T. colubriformis was the main zoonotic species causing hookworm infections in the village. Copyright © 2011 by The American Society of Tropical Medicine and Hygiene.


PubMed | National Institute of Public Health, Niigata University, Station of Malariology, Nagasaki University and 2 more.
Type: Journal Article | Journal: The Korean journal of parasitology | Year: 2016

In the present study, we report on the occurrence of paramphistomes, Fischoederius cobboldi and Paramphistomum epiclitum, in Lao PDR with the basis of molecular data. Parasite materials were collected from bovines bred in Ban Lahanam area, Savannakhet Province, Lao PDR at Lahanam public market. Morphological observations indicated 2 different species of paramphistomes. The mitochondrial gene cox1 of the specimens was successfully amplified by PCR and DNA sequencing was carried out for diagnosis of 11 specimens. Pairwise alignment of cox1 sequences were performed and confirmed F. cobboldi and P. epiclitum infecting bovines in Laos. Although there were many limiting points, as the small number of worm samples, and the restricted access of the animal host materials, we confirmed for the first time that 2 species of paramphistomes, F. cobboldi and P. epiclitum, are distributed in Lao PDR. More studies are needed to confirm the paramphistome species present in Savannakhet and its hosts to clear the natural history of these parasites of ruminants in the region and measure the impact of this parasite infection in the life and health of the local people.


Miao M.,Pennsylvania State University | Wang Z.,Pennsylvania State University | Yang Z.,Kunming Medical College | Yuan L.,Kunming Medical College | And 17 more authors.
PLoS ONE | Year: 2013

The recent detection of clinical Artemisinin (ART) resistance manifested as delayed parasite clearance in the Cambodia-Thailand border area raises a serious concern. The mechanism of ART resistance is not clear; but the P. falciparum sarco/endoplasmic reticulum Ca2+-ATPase (PfSERCA or PfATP6) has been speculated to be the target of ARTs and thus a potential marker for ART resistance. Here we amplified and sequenced pfatp6 gene (~3.6 Kb) in 213 samples collected after 2005 from the Greater Mekong Subregion, where ART drugs have been used extensively in the past. A total of 24 single nucleotide polymorphisms (SNPs), including 8 newly found in this study and 13 nonsynonymous, were identified. However, these mutations were either uncommon or also present in other geographical regions with limited ART use. None of the mutations were suggestive of directional selection by ARTs. We further analyzed pfatp6 from a worldwide collection of 862 P. falciparum isolates in 19 populations from Asia, Africa, South America and Oceania, which include samples from regions prior to and after deployments ART drugs. A total of 71 SNPs were identified, resulting in 106 nucleotide haplotypes. Similarly, many of the mutations were continent-specific and present at frequencies below 5%. The most predominant and perhaps the ancestral haplotype occurred in 441 samples and was present in 16 populations from Asia, Africa, and Oceania. The 3D7 haplotype found in 54 samples was the second most common haplotype and present in nine populations from all four continents. Assessment of the selection strength on pfatp6 in the 19 parasite populations found that pfatp6 in most of these populations was under purifying selection with an average dN/dS ratio of 0.333. Molecular evolution analyses did not detect significant departures from neutrality in pfatp6 for most populations, challenging the suitability of this gene as a marker for monitoring ART resistance.


Sato M.,Niigata University | Pongvongsa T.,Station of Malariology | Sanguankiat S.,Mahidol University | Yoonuan T.,Mahidol University | And 6 more authors.
Journal of Helminthology | Year: 2015

The liver fluke, Opisthorchis viverrini, and the minute intestinal fluke, Haplorchis taichui, are prevalent in many Asian countries. This study analysed the patterns of infections of O. viverrini and H. taichui in Lahanam and Thakhamlien villages (Savannakhet Province, Lao PDR), in two cross-sectional investigations. Out of a total of 207 human participants, post-anthelmintic treatment positivity rates for expelled worms were 170 (82.1%) for H. taichui and 65 (31.4%) for O. viverrini. Both these species co-exist in the study villages. When each parasite was analysed separately, H. taichui infections reached a plateau among people aged >20 years. Opisthorchis viverrini infection rates were highest in the age group 21-30 years, with decreasing infection rates after the age of 30. Our findings indicated that fish-borne trematode infections were more prevalent among adults. Fish, common intermediate hosts, were acquired in the study area for analysis. The examination of 35 species of fish as intermediate hosts found O. viverrini metacercariae in only six species, and these were found mostly during the month of November. Many farmers who live on the rice fields obtain their food from their immediate environment, including these intermediate-host fish, potentially putting them at greater risk of O. viverrini infection. By contrast, H. taichui metacercariae were found in three species of fish obtained from the market, meaning that anyone could consume them and become infected. If people who work in rice fields limit the species of fish they consume, or avoid consuming raw fish during the month of November, they may reduce their risk of O. viverrini infection. © Cambridge University Press 2014.


Sato M.,Mahidol University | Pongvongsa T.,Station of Malariology | Sanguankiat S.,Mahidol University | Yoonuan T.,Mahidol University | And 7 more authors.
Southeast Asian Journal of Tropical Medicine and Public Health | Year: 2010

The utility of differential copro-DNA diagnosis using modified sample preparation steps of small liver and minute intestinal fluke infections was tested. Fecal samples containing parasite eggs were washed extensively with diluted detergent solution. Parasite eggs were concentrated by sedimentation and broken by microwaving before DNA extraction. PCR targeting ITS1 and ITS2 regions were performed using primer specific for Opisthorchis viverrini, Haplorchis taichui and other related species. Of 125 fecal samples, 94 were positive for small trematode eggs by a modified cellophane thick smear method. By ITS1-PCR, 52 samples were positive for O. viverrini, 12 H. taichui and 7 mixed infection. By ITS2-PCR, 63 were positive for O. viverini, 17 H. taichui, and 19 mixed infection. The ITS-PCR assay identified a higher number of opisthorchiasis cases than those with O. viverrini expelled after treatment, but for H. taichui, ITS-PCR identified less than half of the worm expelled cases. These results showed that copro-DNA diagnosis was useful for the differential diagnosis of O. viverrini and H. taichui infection, which could not be discriminated by microscopy.

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