Genetic diversity and host specificity of Blastocystis in reptiles, Eastern Thailand.

Blastocystis inhabits the digestive tracts of a diverse range of hosts. Transmission patterns, including host specificity, and the clinical and public health significance of Blastocystis in humans remain poorly understood. This study aimed to investigate the distribution and genetic diversity of Blastocystis in herbivorous and carnivorous reptiles in Eastern Thailand. A total of 501 faecal samples were collected from 363 iguanas, 79 bearded dragons, 50 tortoises, and nine snakes in an animal breeding farm in Chonburi Province, Eastern Thailand. Detection and differentiation of Blastocystis was based on amplification, sequencing, and phylogenetic analysis of specific small subunit (SSU) ribosomal RNA genes from faecal DNA extracted from the samples. Altogether 101/501 samples (20 %) were polymerase chain reaction (PCR) and sequencing-positive for Blastocystis, 90 (89 %) of which were from iguanas; the remaining positive samples were from African spurred tortoise (n=6), Bearded dragon (n=3), Leopard tortoise (n=1), and Red-footed tortoise (n=1). Phylogenetic analysis revealed that most of the Blastocystis sequences from iguanas were largely similar, and they were distinct from those of the tortoises. Subtype 17 was found in the three bearded dragons and likely reflected Blastocystis from prey animals. This is the largest survey of Blastocystis in reptiles to date. Remarkable differences in Blastocystis colonization rates and genetic diversity were observed between iguanas and other reptile orders, and what was considered Blastocystis colonization was only observed in herbivorous reptiles.

Favipiravir Inhibits Mayaro Virus Infection in Mice.

Mayaro virus (MAYV) is an emergent alphavirus that causes MAYV fever. It is often associated with debilitating symptoms, particularly arthralgia and myalgia. MAYV infection is becoming a considerable health issue that, unfortunately, lacks a specific antiviral treatment. Favipiravir, a broad-spectrum antiviral drug, has recently been shown to exert anti-MAYV activity in vitro. In the present study, the potential of Favipiravir to inhibit MAYV replication in an in vivo model was evaluated. Immunocompetent mice were orally administrated 300 mg/kg/dose of Favipiravir at pre-, concurrent-, or post-MAYV infection. The results showed a significant reduction in infectious viral particles and viral RNA transcripts in the tissues and blood of the pre- and concurrently treated infected mice. A significant reduction in the presence of both viral RNA transcript and infectious viral particles in the tissue and blood of pre- and concurrently treated infected mice was observed. By contrast, Favipiravir treatment post-MAYV infection did not result in a reduction in viral replication. Interestingly, Favipiravir strongly decreased the blood levels of the liver disease markers aspartate- and alanine aminotransferase in the pre- and concurrently treated MAYV-infected mice. Taken together, these results suggest that Favipiravir is a potent antiviral drug when administered in a timely manner.

Insecticidal and Histopathological Effects of Ageratum conyzoides Weed Extracts against Dengue Vector, Aedes aegypti.

Crude extracts and essential oils of A. conyzoides were tested with larva and adult stages of Ae. aegypti mosquitoes to determine their insecticidal properties. The crude extracts and essential oils came from three varieties of A. conyzoides (with white flowers, purple flowers, or white-purple flowers) and from two places on each plant (leaves and flowers), giving six types overall: leaf-white (LW); leaf-purple (LP); leaf white-purple (LW-P); flower-white (FW); flower-purple (FP); and flower white-purple (FW-P). Chemical constituents and components of the essential oils were identified using gas chromatography-mass spectrometry (GC-MS). Electron microscopic and histopathological studies were performed to determine the toxicological effects on mosquitoes in terms of morphological alterations. The six types of crude extracts exhibited no activity against individuals in the larval stages. However, six types of essential oils were effective against adult Ae. aegypti females. The mortality of adult Ae. aegypti females was higher from leaf extracts, particularly LP (median lethal dose, LD50 = 0.84%). The number of chemical constituents identified by GC-MS was high in flowers, especially W-P. Precocene I was the most abundant chemical component among the five types of essential oils, except in LP, in which precocene II was the most abundant. Histopathological alterations in adult Ae. aegypti females included compound eye degeneration, muscular damage with cellular infiltration, gut epithelial degeneration and necrosis, pyknotic nuclei in the malpighian epithelium and ovarian cell degeneration. FW and FP plant types exhibited the highest severity of histopathological alterations in mosquitoes compared with other plants, probably owing to the presence of monoterpene compounds in their tissues. The present study demonstrated LP plant extracts from A. conyzoides could be effective adulticides against adult Ae. aegypti. As natural products are biodegradable and exhibit low toxicity to mammalian and non-target organisms, they are suitable candidates for use in vector control programmes.

Efficacy of Ageratum conyzoides extracts against Giardia duodenalis trophozoites: an experimental study.

BACKGROUND: Giardia duodenalis causes giardiasis in humans, particularly in developing countries. Despite the availability of treatments, resistance to some of the commercial anti-Giardia drugs has been reported in addition to their harmful side effects. Therefore, novel treatments for giardiasis are required. In this study, we aimed to assess the in vitro activity of crude extracts of Ageratum conyzoides against G. duodenalis trophozoites. METHODS: Plants were classified into three groups based on their flower colors: white (W), purple (P), and white-purple (W-P). Plants were separately cut into leaf (L) and flower (F) parts. Changes in internal organelle morphology of trophozoites following exposure to crude extracts were assessed using transmission electron microscopy (TEM). In subsequent experiments, efficacy of the most active essential oils from crude extracts [half maximal inhibitory concentrations (IC50) ≤ 100 µg/mL] against G. duodenalis trophozoites was tested. In vitro anti-Giardia assays using essential oils were performed in the same way as those performed using crude extracts. RESULTS: LW-P and FP extracts showed high activity (IC50 ≤ 100 µg/mL) against G. duodenalis trophozoites, with IC50 ± SD values of 45.67 ± 0.51 and 96.00 ± 0.46 µg/mL, respectively. In subsequent experiments, IC50 ± SD values of LW-P and FP essential oils were 35.00 ± 0.50 and 89.33 ± 0.41 µg/mL, respectively. TEM revealed the degeneration of flagella and ventral discs of G. duodenalis trophozoites following exposure to crude extracts. CONCLUSION: Crude LW-P and FP extracts of A. conyzoides showed the highest activity against G. duodenalis. Exposure to crude extract induced changes in the flagella and ventral discs of G. duodenalis trophozoites, which play important roles in attachment to the surface of mucosal cells. Our results suggest that the tested extracts warrant further research in terms of their efficacy and safety as giardiasis treatment.

Blastocystis infection and subtype distribution in humans, cattle, goats, and pigs in central and western Thailand.

Blastocystis is a common intestinal pathogen of humans and a variety of animals, with various host-specific subtypes. The aim of this study was to determine the prevalence and subtype distribution of Blastocystis in humans and domestic animals, Thailand. 113 stool samples were collected from pigs, goats, and cattle in Ayutthaya Province (AP; central Thailand) and 218 stool samples were collected from pigs, dogs, cats, chickens, and humans in Kanchanaburi Province (KP; western Thailand). Blastocystis was detected by nested PCR targeting the SSU rRNA gene. Subtypes were identified by DNA sequencing, and phylogenetic analysis was conducted. The overall prevalence of Blastocystis in animals was 76.1% (86/113) and 11.88% (12/101) in AP and KP, respectively, and the prevalence in humans was 12.82% (15/117) in KP. The prevalence of Blastocystis in the AP and KP pigs were 87.88% (29/33) and 20.37% (11/54), respectively. Blastocystis ST5 was the most abundant in pigs in both areas while Blastocystis ST10 and ST12 were most frequently found in cattle and goats. In addition, low percentage of Blastocystis ST1 and Blastocystis ST14 were found in pigs and goats, respectively. In this study, Blastocystis ST3, followed by ST2 and ST1 were predominantly found in humans. In conclusion, pigs may be a natural host of Blastocystis and this ST may be the pig-adapted ST in the studied areas, in this study.

Blastocystis subtype 5: Predominant subtype on pig farms, Thailand.

Blastocystis is a unicellular protist most commonly detected in humans and a variety of animals. The predominant mode of its transmission is the fecal-oral route, but its zoonotic potential is not completely understood. The objective of this study was to determine the presence and genetic diversity of Blastocystis on pig farms in Nakhon Pathom Province, Central Thailand. A total of 154 human and 90 pig stool samples were collected and analyzed. Nested PCR detected Blastocystis in 35.55% of the pig samples and 6.49% of the human samples. Subtyping based on regions of the small-subunit ribosomal RNA (SSU rRNA) gene identified three Blastocystis subtypes in pigs and humans: ST1, ST3, and ST5. Blastocystis ST5 was the predominant subtype, followed by ST1 and then ST3. All the sequences from the Blastocystis-positive samples from both pigs and humans were closely related. This study reveals a possibility of low host specificity of Blastocystis STs (ST1, ST3 and ST5) on pig farms in Thailand. We tentatively suggest that close contact with or exposure to pig stools may be a significant source of Blastocystis detected in pig handlers. Further studies are required to confirm the zoonotic transmission of this organism in Thailand, because pigs may play an important role in the transmission of Blastocystis.

Zoonotic potential of Enterocytozoon genotypes in humans and pigs in Thailand.

Enterocytozoon bieneusi is an opportunistic intestinal pathogen infecting humans and a variety of animals. Its mode of transmission and zoonotic potential are not completely understood. E. bieneusi has been frequently identified in pigs. The objective of our study was to investigate E. bieneusi in pigs and humans in Western and Central Thailand to determine its presence, genetic diversity, and zoonotic potential. A total of 277 human and 210 pig faecal samples were collected and analysed. E. bieneusi was found in 5.4% and 28.1% of human and pig samples, respectively, by nested PCR. Genotyping based on the internal transcribed spacer regions of the small subunit ribosomal RNA demonstrated three known genotypes (D, H, PigEb10) and eight novel genotypes (TMH1-8) in humans, and five known genotypes (D, EbpA, EbpC, H, O) and 11 novel genotypes (TMP1-11) in pigs. All known genotypes identified in humans and pigs had zoonotic potential. Further studies are needed to evaluate zoonotic risk of novel genotypes, as pigs may play an important role in the transmission of E. bieneusi.

Molecular identification of Cryptosporidium spp. in seagulls, pigeons, dogs, and cats in Thailand.

Zoonotic Cryptosporidium spp., particularly C. meleagridis, C. canis, and C. felis, are enteric protozoa responsible for major public health concerns around the world. To determine the spread of this parasite in Thailand, we conducted molecular identification of Cryptosporidium spp. from animal samples around the country, by collecting and investigating the feces of seagulls (Chroicocephalus brunnicephalus and Chroicocephalus ridibundus), domestic pigeons (Columba livia domestica), dogs, and cats. Seagull and pigeon samples were collected at the seaside and on the riverside to evaluate their potential for waterborne transmission. Ten pigeon samples were combined into one set, and a total of seven sets were collected. Seventy seagull samples were combined into one set, and a total of 13 sets were collected. In addition, 111 dog samples were collected from cattle farms, and 95 dog and 80 cat samples were collected from a temple. We identified C. meleagridis in pigeons, Cryptosporidium avian genotype III in seagulls, C. canis in dogs, and C. felis in cats. In the temple, the prevalence was 2.1% (2/95) for dogs and 2.5% (2/80) for cats. No Cryptosporidium was found in dog samples from cattle farms. These are the first findings of C. meleagridis in domestic pigeons, and Cryptosporidium avian genotype III in seagulls. Our study invites further molecular epidemiological investigations of Cryptosporidium in these animals and their environment to evaluate the public health risk in Thailand.