Agents of food-borne zoonoses confirmed to parasitise newly-recorded in Thailand snails

Parasitic flatworms known as agents of food-borne zoonoses were confirmed to use several species of thiarid snails, commonly found in freshwater and brackish environments in southeast Asia, as their first intermediate host. These parasites can cause severe ocular infections in humans who consume raw or improperly cooked fish that have fed on infected snails.

Parasitic flatworms known as agents of food-borne zoonoses were confirmed to use several species of thiarid snails, commonly found in freshwater and brackish environments in southeast Asia, as their first intermediate host. These parasites can cause severe ocular infections in humans who consume raw or improperly cooked fish that have fed on infected snails. The study, conducted in South Thailand by Thai and German researchers and led by Kitja Apiraksena, Silpakorn University, is published in the peer-reviewed open-access journal Zoosystematics and Evolution.

“Trematode infections are major public health problems affecting humans in southeast Asia. Trematode infections depend not only on the habit of people, but also on the presence of first and second intermediate host species, resulting in the endemic spread of parasites, such as intestinal and liver flukes in Thailand”.

explain the scientists.

The snails of concern belong to the genus Stenomelania, have elongated and pointed shells and can be found near and in the brackish water environment of estuaries in the Oriental Region, from India to the Western Pacific islands. Worryingly enough, science does not know much else about these snails to date. Further, these species are hard to distinguish from related trumpet snails, because of the similarities in their shell morphology.

In order to provide some basic knowledge about the parasitic worms in Thailand and neighbouring countries, the research team collected a total of 1,551 Stenomelania snails, identified as four species, from streams and rivers near the coastline of the south of Thailand in Krabi, Trang and Satun Provinces. Of them, ten were infected with trematodes. The parasites were found at seven of the studied localities and belonged to three different species. In Krabi Province, the researchers observed all three species.

Speculating on their presence, the scientists suspect that it could be related to the circulation of sea currents, as the flow of water along the Andaman coast is affected by the monsoon season.

In conclusion, the researchers note that it is a matter of public health that further research looks into the biodiversity and biology of these snails, in order to improve our knowledge about the susceptibility of Stenomelania snails to food-borne zoonotic.

“This finding indicated that the resulting parasitic diseases are still largely neglected in tropical medicine, so further studies should be performed on the prevalence of various trematode-borne diseases in locations with snail occurrences in Thailand,”

they say.

Research article:

Apiraksena K, Namchote S, Komsuwan J, Dechraksa W, Tharapoom K, Veeravechsukij N, Glaubrecht M, Krailas D (2020) Survey of Stenomelania Fisher, 1885 (Cerithioidea, Thiaridae): The potential of trematode infections in a newly-recorded snail genus at the coast of Andaman Sea, South Thailand. Zoosystematics and Evolution 96(2): 807-819. https://doi.org/10.3897/zse.96.59448

Medicinal mushroom newly reported from Thailand helps reveal optimum growth conditions

Globally recognised medicinal mushroom is reported for the first time in Thailand. The study also presents the first assessment of the optimum growth conditions for the species.

A species of globally recognised medicinal mushroom was recorded for the first time in Thailand. Commonly referred to as lingzhi, the fungus (Ganoderma tropicum) was collected from the base of a living tree in Chiang Rai Province, Northern Thailand. Additionally, the study reports the first assessment of the optimum conditions needed for the species to grow its mycelia (the vegetative part of a fungus consisting of a branching network of fine, thread-like structures) and spread its colony.

The discoveries are published in the open-access journal MycoKeys by a research team from the Chinese Academy of Sciences, University of Chinese Academy of SciencesWorld Agroforestry CentreKunming Institute of Botany (China) and Center of Excellence in Fungal ResearchMae Fah Luang University (Thailand), led by Thatsanee Luangharn.

Over the last centuries, the studied mushroom and its related species in the genus Ganoderma have been used extensively in traditional Asian medicines due to their natural bioactive compounds, including polysaccharides, triterpenoids, sterols, and secondary metabolites, which are used in the treatment of various diseases. Other compounds derived from lingzhi, such as the studied species, also demonstrate antimicrobial activities. The medicinal use of these mushrooms is recognised by the World Health Organization and they are featured in the Chinese Pharmacopoeia.

The studied mushroom belongs to a group known to be parasitic or pathogenic on a wide range of tree species. The species is characterised with strongly laccate fruiting bodies and a cap with distinctly dark brown base colour and reddish shades. It grows to up to 7-12 cm in length, 4-8 cm in width and is up to 1.5 cm thick. While the mushroom has so far been widely reported from tropical areas, including mainland China, Taiwan and South America, it had never been recorded from Thailand.

During their research, the scientists found that mycelial production for Ganoderma tropicum is most successful on Potato Dextrose Agar, Malt Extract Agar, and Yeast extract Peptose Dextrose Agar, at a temperature of 25-28 °C and 7-8 pH. Unfortunately, mushroom fruiting was not achieved in the experiment.

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Original source:

Luangharn T, Karunarathna SC, Mortimer PE, Hyde KD, Thongklang N, Xu J (2019) A new record of Ganoderma tropicum (Basidiomycota, Polyporales) for Thailand and first assessment of optimum conditions for mycelia production. MycoKeys 51: 65-83. https://doi.org/10.3897/mycokeys.51.33513

Two new species of stone centipedes found hiding in larch forests in China

Scientists described two species of previously unknown stone centipedes from China. Now housed at the Hengshui University, China, where all members of the team work, the studied specimens were all collected in the leaf litter or under rocks in larch forests.

Having conducted their research across China, researchers Dr Sujian Pei, Yanmin Lu, Haipeng Liu, Dr Xiaojie Hou and Dr Huiqin Ma announced the two new species – Lithobius (Ezembius) tetraspinus and Hessebius luculentus – in two articles published in the open access journal ZooKeys.

Stone centipedes are the species which belong to the order Lithobiomorpha. These centipedes are anamorphic, meaning that they grow additional pair of legs as they moult and develop additional body segments. By the time they are fully grown, these count 15 in total. Unlike earlier predecessors, stone centipedes do not have the compound eyes we know from insects. Instead, stone centipedes see through simple eyes, sometimes a group of simple eyes, or, if living exclusively underground, they might have no eyes at all.19980 New centipede China L. tetraspinus

One of the newly discovered species, Lithobius (Ezembius) tetraspinus, is recorded from Hami City, Xinjiang Autonomous Region, northwestern China. The studied specimens were collected from moderately moist larch forest habitats at altitude of 950 to 1000. There, the small predominantly brown centipedes, measuring no more than about 13 mm in body length, were hiding under rodeside stones and leaf litter.

The second previously unknown centipede, Hessebius luculentus, discovered in Shandan County, Qinghai-Tibet Plateau, is slightly larger – reaching up to 20 mm. Its colours are a mix of yellow and brown with the odd grey or red hue. While it has the same preference for relatively moist habitats, this species lives at greater altitude. It has been reported from forest floor at about 1400 m above sea level.

In both papers, the authors point out that while the myriapod fauna of China remains generally poorly known, even less attention has been given to the order of stone centipedes.

The research articles are included in the special issue “Proceedings of the 17th International Congress of Myriapodology, Krabi, Thailand”. The congress, organised by Prof. Somsak Panha, Chulalongkorn University, Bangkok, was held in July 2017.

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Original source:

Pei S, Lu Y, Liu H, Hou X, Ma H (2018) Lithobius (Ezembius) tetraspinus, a new species of centipede from northwest China (Lithobiomorpha, Lithobiidae). In: Stoev P, Edgecombe GD (Eds) Proceedings of the 17th International Congress of Myriapodology, Krabi, Thailand. ZooKeys 741: 203-217. https://doi.org/10.3897/zookeys.741.19980

Ma H, Lu Y, Liu H, Hou X, Pei S (2018) Hessebius luculentus, a new species of the genus Hessebius Verhoeff, 1941 from China (Lithobiomorpha, Lithobiidae). In: Stoev P, Edgecombe GD (Eds) Proceedings of the 17th International Congress of Myriapodology, Krabi, Thailand. ZooKeys 741: 193-202. https://doi.org/10.3897/zookeys.741.20061

Counting stars: Illegal trade of Indian star tortoises is a far graver issue

Patterned with star-like figures on their shells, Indian star tortoises can be found in private homes across Asia, where they are commonly kept as pets. One can also see them in religious temples, praised as the living incarnation of the Hindu god Vishnu. How did they get there? Suspicious of a large-scale illegal international trade of these tortoises that could in fact pose a grave threat to the survival of the Indian Star tortoise, a team of researchers, led by Dr. Neil D’Cruze from Wildlife Conservation Research Unit, University of Oxford, and World Animal Protection, London, spent 17 months investigating the case focusing on India and Thailand. They have their study published in the open-access journal Nature Conservation.

The present study established that at least 55,000 Indian star tortoise individuals are being poached over the span of a year from a single trade hub in India. Helped by a number of herpetologists and wildlife enforcement officials, the researchers have tracked signals about how sophisticated criminal gangs are exploiting “legal loopholes” and people alike, taking advantage of rural communities and urban consumers in India and other Asian countries.

“We were shocked at the sheer scale of the illegal trade in tortoises and the cruelty inflicted upon them,” comments Dr. Neil D’Cruze. “Over 15 years ago wildlife experts warned that the domestic trade in Indian star tortoises needed to be contained before it could become established as an organised international criminal operation.”

“Unfortunately, it seems that our worst nightmare has come true – sophisticated criminal gangs are exploiting both impoverished rural communities and urban consumers alike,” he also added. “Neither group is fully aware how their actions are threatening the welfare and conservation of these tortoises.”

Although deemed of “Least Concern” on the IUCN Red List when last formally assessed back in 2000, the Indian star tortoise and its increasing illegal poaching and trading can easily lead to a serious risk of the species’ extinction. Other dangers of such unregulated activities include the introduction of invasive species and diseases.

Having spent a year among a rural hunter-gatherer community, researchers established the collection of at least 55,000 juvenile wild Indian star tortoises between January and December 2014. This is already between three and six times more than the last such record dating from about ten years ago.

Collectors tend to poach juvenile tortoises, but it is not rare for them to also catch adults. Based on the individual’s age and health, the tortoises are later sold to vendors at a price of between 50 and 300 Indian Rupees (INR), or between 1 and 5 USD, per animal. “Therefore, we conservatively estimate (assuming no mortalities) that the collector engagement in this illegal operation has a collective annual value of up to 16,500,000 INR (263,000 USD) for their impoverished communities,” comment the researchers.

Consumers seek the Indian star tortoise for either exotic pets or spiritual purposes. With their star-like radiating yellow patterns splashed with black on their shells, not only is this tortoise species an attractive animal, but it was also found to be considered as a good omen among the locals in the Indian state of Gujarat. During their survey, the researchers found over a hundred hatchlings in a single urban household. However, their owner claimed that none of them was kept with commercial intent, although some of the tortoises were meant for close friends and relatives.

On the other hand, there was a case where the researchers came across a Shiva temple hosting a total of eleven Indian star tortoises. Temple representatives there confirmed that the tortoise is believed to represent an incarnation of the Hindu god Vishnu, one of the three central gods in the religion, recognised as the preserver and protector of the universe.

In India vendors do not show the reptiles in public, but they are made available upon a special request. If paid for in advance, a vendor can also supply a larger quantity of the animals at a price ranging from 1,000 to 3,000 INR (15 to 50 USD) per animal. The researchers managed to see seven captive tortoises in private, including six juveniles and one adult, all in visibly poor health. Disturbingly, in order to reach these vendors, the collected tortoise are usually wrapped in cloths and packed into suitcases. Covered by a ‘mask’ of legal produce such as fruit and vegetables, they are transported to the ‘trade hubs’. They are also smuggled abroad to satisfy consumer demand among the growing middle classes in countries such as Thailand and China.

“Despite being protected in India since the 1970’s, legal ‘loopholes’ in other Asian countries such as Thailand and China appear to undermine India’s enforcement efforts,” explains Mr. Gajender Sharma, India’s Director at World Animal Protection, “They are smuggled out of the country in confined spaces, it’s clear there is little or no concern about the welfare of these reptiles.”

“World Animal Protection is concerned about the suffering that these tortoises endure,” he further notes. “We are dealing with an organised international criminal operation which requires an equally organised international approach to combat it.”

As a result of their study, the authors conclude that more research into both the illegal trafficking of Indian star tortoise and its effects as well as the consumer demand is urgently needed in order to assess, address and subsequently tackle the issue.

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Original source:

D’Cruze N, Singh B, Morrison T, Schmidt-Burbach J, Macdonald DW, Mookerjee A (2015) A star attraction: The illegal trade in Indian Star Tortoises. Nature Conservation 13: 1-19. doi:10.3897/natureconservation.13.5625