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Blastocystis occurrence in water sources worldwide from 2005 to 2022: a review

Attah AO, Sanggari A, Li LI, Nik Him NAII, Ismail AH, Meor Termizi FH

Parasitol Res, 2023 Jan;122(1):1-10.
PMID: 36434314 DOI: 10.1007/s00436-022-07731-0

There has been increasing interest in the study of Blastocystis in the last two decades. Many studies have been carried out in human and animal hosts including environmental sources, but there is little or no information on the occurrence of Blastocystis in water sources worldwide. Therefore, this study aimed at assessing the occurrence of Blastocystis in water sources across the world from 2005 to 2022, noting the method of detection and the distribution of the subtypes from various water sources. A literature search was performed on internet-based databases including Google search, PubMed, Scopus, and Web of Science. Upon application of the criteria for inclusion, 25 articles revealing the occurrence of Blastocystis in water sources in 15 countries were included in the review. Blastocystis occurrence varies across water sources ranging from 0% in a drinking water source in Venezuela to 100% in rivers; well water, stored water, and fishpond in Nepal and Malaysia; and fountain water, irrigation water, and rainwater in Italy, Spain, and Thailand. The occurrence of the parasite was significantly associated with the coliform count, temperature, conductivity, dissolved oxygen, turbidity, total dissolved solids, and chemical oxygen demand. A total of 11 Blastocystis subtypes were identified in water sources worldwide, namely, ST1-ST8, ST10, ST23, and ST26 in which ST1 and ST3 were the most prevalent subtypes. Considering the importance of Blastocystis as a waterborne parasite, the subtype distribution and morphological distinction in water sources need to be carried out using molecular and electron microscopic techniques. Existing studies have covered only about 10% of the world's countries.

Matched MeSH terms: Feces/parasitology
Intestinal parasitic infections and risk factors among the population in Cambodia

La N, Leng M, Rattanapitoon K, Pechdee P, Boonsuya A, Arunsan P, et al.

Trop Biomed, 2022 Dec 01;39(4):539-546.
PMID: 36602213 DOI: 10.47665/tb.39.4.009

Many species of helminths and protozoa caused intestinal parasitic infections (IPIs). It belongs to neglected tropical diseases (NTDs) and remains a major public health problem in several Southeast Asian countries. The present study aimed to investigate the prevalence of IPIs and associated risk factors among the population in Kratie Province in northeastern Cambodia and Phnom Penh is the capital that locates in southern Cambodia. Fecal specimens (n=366) were collected in 10 villages in Kratie Province and Phnom Penh from 2019 to 2021. They were processed using the formalin ethyl-acetate concentration technique (FECT) to investigate parasites at egg and cyst stages and then examined under a light microscope. The results revealed that the prevalence of IPIs among the population in Kratie Province (n=317) and Phnom Penh (n=49) was 16.12% (n=59); of Kratie Province (n=50, 13.66%) and Phnom Penh (n=9, 2.46%), 12.02% (n=44) were helminths and 4.10% (n=15) were protozoa. The parasitic infection rate was higher in males (9.02%) than in females (7.10%) and more likely to be due to helminths (7.38%) than protozoa (1.64%). Prevalence of Opisthorchis viverrini was the highest (5.74%), followed by those of Entamoeba coli (4.10%), hookworm (3.83%), Ascaris lumbricoides (1.10%), Hymenolepis nana (1.09%), Taenia spp. (0.54%), Trichuris trichiura (0.55%), and Enterobius vermicularis (0.27%), respectively. Moreover, O. viverrini infection was the most common infection in the <20-year age group in Kratie Province. In addition, the bivariate and multivariate analyses showed that the association between gender. Gender was a significant risk factor positively associated with O. viverrini and hookworm infections (ORadj=0.318, 95% CI=0.122-0.8270, P=0.019 and ORadj=0.085, 95% CI=0.017-0.436, P=0.003, respectively). In conclusion, the IPIs were highly prevalent, especially O. viverrini and hookworm infections, among the population in Cambodia. These IPIs impact the public health burden but can be prevented by education regarding good sanitary practices in this community.

Matched MeSH terms: Feces/parasitology
Fulltext Lernaea cyprinacea Linnaeus, 1758 (Copepoda: Lernaeidae) infection on Betta rubra Perugia, 1893 (Anabantiformes: Osphronemidae) from Aceh Province, Indonesia

Nur FM, Batubara AS, Fadli N, Rizal S, Siti-Azizah MN, Wilkes M, et al.

Rev Bras Parasitol Vet, 2022;31(1):e020421.
PMID: 35293430 DOI: 10.1590/S1984-29612022015

Betta rubra is an ornamental freshwater fish endemic to northern Sumatra, Indonesia. The B. rubra population has decreased in recent decades, and is classified as an endangered species in the IUCN Red List. This study aims to report for the first time infection by L. cyprinacea in B. rubra harvested from the Aceh Besar region of Indonesia. The fish samples were obtained from the Cot Bira tributaries, Aceh Besar District, Indonesia from January to December 2020. The results showed that the parasite infected 6 out of 499 samples in August and September, with a prevalence and intensity rate of 1% and 2 parasites/fish, respectively. The eyes and pectoral fins were the common infection sites. Despite B. rubra is not an optimal host (small size) for the parasite, this parasite might serve as additional threatening factors for the endangered B. rubra fish population.

Matched MeSH terms: Fishes/parasitology
Fulltext Plasmodium knowlesi Cytoadhesion Involves SICA Variant Proteins

Peterson MS, Joyner CJ, Lapp SA, Brady JA, Wood JS, Cabrera-Mora M, et al.

Front Cell Infect Microbiol, 2022;12:888496.
PMID: 35811680 DOI: 10.3389/fcimb.2022.888496

Plasmodium knowlesi poses a health threat throughout Southeast Asian communities and currently causes most cases of malaria in Malaysia. This zoonotic parasite species has been studied in Macaca mulatta (rhesus monkeys) as a model for severe malarial infections, chronicity, and antigenic variation. The phenomenon of Plasmodium antigenic variation was first recognized during rhesus monkey infections. Plasmodium-encoded variant proteins were first discovered in this species and found to be expressed at the surface of infected erythrocytes, and then named the Schizont-Infected Cell Agglutination (SICA) antigens. SICA expression was shown to be spleen dependent, as SICA expression is lost after P. knowlesi is passaged in splenectomized rhesus. Here we present data from longitudinal P. knowlesi infections in rhesus with the most comprehensive analysis to date of clinical parameters and infected red blood cell sequestration in the vasculature of tissues from 22 organs. Based on the histopathological analysis of 22 tissue types from 11 rhesus monkeys, we show a comparative distribution of parasitized erythrocytes and the degree of margination of the infected erythrocytes with the endothelium. Interestingly, there was a significantly higher burden of parasites in the gastrointestinal tissues, and extensive margination of the parasites along the endothelium, which may help explain gastrointestinal symptoms frequently reported by patients with P. knowlesi malarial infections. Moreover, this margination was not observed in splenectomized rhesus that were infected with parasites not expressing the SICA proteins. This work provides data that directly supports the view that a subpopulation of P. knowlesi parasites cytoadheres and sequesters, likely via SICA variant antigens acting as ligands. This process is akin to the cytoadhesive function of the related variant antigen proteins, namely Erythrocyte Membrane Protein-1, expressed by Plasmodium falciparum.

Matched MeSH terms: Erythrocytes/parasitology
Fulltext Spatial analyses of Plasmodium knowlesi vectors with reference to control interventions in Malaysia

Pramasivan S, Ngui R, Jeyaprakasam NK, Low VL, Liew JWK, Vythilingam I

Parasit Vectors, 2023 Oct 09;16(1):355.
PMID: 37814287 DOI: 10.1186/s13071-023-05984-x

BACKGROUND: Malaria parasites such as Plasmodium knowlesi, P. inui, and P. cynomolgi are spread from macaques to humans through the Leucosphyrus Group of Anopheles mosquitoes. It is crucial to know the distribution of these vectors to implement effective control measures for malaria elimination. Plasmodium knowlesi is the most predominant zoonotic malaria parasite infecting humans in Malaysia.
METHODS: Vector data from various sources were used to create distribution maps from 1957 to 2021. A predictive statistical model utilizing logistic regression was developed using significant environmental factors. Interpolation maps were created using the inverse distance weighted (IDW) method and overlaid with the corresponding environmental variables.
RESULTS: Based on the IDW analysis, high vector abundances were found in the southwestern part of Sarawak, the northern region of Pahang and the northwestern part of Sabah. However, most parts of Johor, Sabah, Perlis, Penang, Kelantan and Terengganu had low vector abundance. The accuracy test indicated that the model predicted sampling and non-sampling areas with 75.3% overall accuracy. The selected environmental variables were entered into the regression model based on their significant values. In addition to the presence of water bodies, elevation, temperature, forest loss and forest cover were included in the final model since these were significantly correlated. Anopheles mosquitoes were mainly distributed in Peninsular Malaysia (Titiwangsa range, central and northern parts), Sabah (Kudat, West Coast, Interior and Tawau division) and Sarawak (Kapit, Miri, and Limbang). The predicted Anopheles mosquito density was lower in the southern part of Peninsular Malaysia, the Sandakan Division of Sabah and the western region of Sarawak.
CONCLUSION: The study offers insight into the distribution of the Leucosphyrus Group of Anopheles mosquitoes in Malaysia. Additionally, the accompanying predictive vector map correlates well with cases of P. knowlesi malaria. This research is crucial in informing and supporting future efforts by healthcare professionals to develop effective malaria control interventions.

Matched MeSH terms: Mosquito Vectors/parasitology
Zoonotic simian malaria parasites in free-ranging Macaca fascicularis macaques and human malaria patients in Thailand, with a note on genetic characterization of recent isolates

Narapakdeesakul D, Pengsakul T, Kaewparuehaschai M, Thongsahuan S, Moonmake S, Lekcharoen P, et al.

Acta Trop, 2023 Dec;248:107030.
PMID: 37742788 DOI: 10.1016/j.actatropica.2023.107030

Despite the natural occurrences of human infections by Plasmodium knowlesi, P. cynomolgi, P. inui, and P. fieldi in Thailand, investigating the prevalence and genetic diversity of the zoonotic simian malaria parasites in macaque populations has been limited to certain areas. To address this gap, a total of 560 long-tailed macaques (Macaca fascicularis) and 20 southern pig-tailed macaques (M. nemestrina) were captured from 15 locations across 10 provinces throughout Thailand between 2018 and 2021 for investigation of malaria, as were 15 human samples residing in two simian-malaria endemic provinces, namely Songkhla and Satun, who exhibited malaria-like symptoms. Using PCR techniques targeting the mitochondrial cytb and cox1 genes coupled with DNA sequencing, 40 long-tailed macaques inhabiting five locations had mono-infections with one of the three simian malaria species. Most of the positive cases of macaque were infected with P. inui (32/40), while infections with P. cynomolgi (6/40) and P. knowlesi (2/40) were less common and confined to specific macaque populations. Interestingly, all 15 human cases were mono-infected with P. knowlesi, with one of them residing in an area with two P. knowlesi-infected macaques. Nucleotide sequence analysis showed a high level of genetic diversity in P. inui, while P. cynomolgi and P. knowlesi displayed limited genetic diversity. Phylogenetic and haplotype network analyses revealed that P. inui in this study was closely related to simian and Anopheles isolates from Peninsular Malaysia, while P. cynomolgi clustered with simian and human isolates from Asian countries. P. knowlesi, which was found in both macaques and humans in this study, was closely related to isolates from macaques, humans, and An. hackeri in Peninsular Malaysia, suggesting a sylvatic transmission cycle extending across these endemic regions. This study highlights the current hotspots for zoonotic simian malaria and sheds light on the genetic characteristics of recent isolates in both macaques and human residents in Thailand.

Matched MeSH terms: Macaca fascicularis/parasitology
New species of the fleas Farhangia and Nestivalius, from endemic rodents in Sulawesi, Indonesia

Mardon DK, Durden LA

Med Vet Entomol, 2003 Mar;17(1):75-86.
PMID: 12680929 DOI: 10.1046/j.1365-2915.2003.00410.x

The fleas (Siphonaptera: Pygiopsyllidae) Farhangia quattuordecimdentata sp. n. and Farhangia sedecimdentata sp. n. are described from pygmy squirrels (Prosciurillus spp.), and Nestivalius sulawesiensis sp. n. from murine rodents, all from Sulawesi, Indonesia. Both new species of Farhangia were collected in Central Sulawesi (Sulawesi Tengah); F. quattuordecimdentata sp. n. was recovered mainly from P. murinus, whereas F. sedecimdentata sp. n. was recovered mainly from P. leucomus. These new species are compared with the two previously described species of Farhangia: F. celebensis (Ewing) from P. murinus in North Sulawesi (Sulawesi Utara) and F. sciuri (Ewing) from the tree squirrel Callosciurus prevosti in Sabah (Borneo). Nestivalius sulawesiensis sp. n. was collected from six species of endemic murine rodents in both North and Central Sulawesi. It is compared to the morphologically similar N. pomerantzi (Traub) from Mindanao, which parasitizes murine hosts that are endemic to the Philippines.

Matched MeSH terms: Rodentia/parasitology*
The role and influence of bacteria on the growth of Blastocystis sp. subtype 3

Kaur CP, Yong CC, Rajamanikam A, Samudi C, Kumar S, Bhassu S, et al.

Parasitol Res, 2023 Jul;122(7):1463-1474.
PMID: 37162590 DOI: 10.1007/s00436-023-07842-2

Blastocystis sp. is an enteric protistan parasite that affects individuals worldwide with gastrointestinal symptoms such as abdominal discomfort, diarrhea, and flatulence. However, its pathogenicity is controversial due to its presence among asymptomatic individuals. Blastocystis sp. subtype 3 (ST3) is the most prevalent subtype among humans that have been associated with irritable bowel syndrome (IBS), Crohn's disease, ulcerative colitis, and colorectal cancer. Axenization of the parasite has been shown to impede its growth thus revealing the importance of accompanying bacteria in ensuring Blastocystis sp. survival. This study aims to identify the influence of accompanying bacteria on the growth of Blastocystis sp. ST3. Blastocystis sp. cultures were treated with Meropenem, Vancomycin, and Amoxicillin-Clavulanic acid (Augmentin). Bacteria-containing supernatant of antibiotic-treated and control cultures were isolated and identified through 16 s rRNA sequencing. Morphological changes of antibiotic-treated Blastocystis sp. ST3 were also observed. The cultures treated with meropenem and augmentin exhibited opposing effects with reduced growth of isolates from symptomatic patients and a significant increase in asymptomatic isolates. Whereas, vancomycin-treated cultures had no difference in the growth of Blastocystis sp. ST3 isolates from symptomatic and asymptomatic patients. Isolates from symptomatic and asymtomatic patients had 6 and 2 distinct bacterial species identified with Proteus mirabilis as the common bacteria among both types of isolates. Morphologically, Blastocystis sp. ST3 cultures exposed to meropenem and augmentin demonstrated an increase in pre-cystic forms. These findings demonstrate the effects of accompanying bacteria on the growth of Blastocystis sp. ST3 that could translate into clinical manifestations observed among Blastocystis sp.-infected patients.

Matched MeSH terms: Feces/parasitology
Fulltext High transmission efficiency of the simian malaria vectors and population expansion of their parasites Plasmodium cynomolgi and Plasmodium inui

Jeyaprakasam NK, Low VL, Pramasivan S, Liew JWK, Wan-Sulaiman WY, Vythilingam I

PLoS Negl Trop Dis, 2023 Jun;17(6):e0011438.
PMID: 37384790 DOI: 10.1371/journal.pntd.0011438

BACKGROUND: The elimination of malaria in Southeast Asia has become more challenging as a result of rising knowlesi malaria cases. In addition, naturally occurring human infections with other zoonotic simian malaria caused by Plasmodium cynomolgi and Plasmodium inui adds another level of complexity in malaria elimination in this region. Unfortunately, data on vectors which are responsible for transmitting this zoonotic disease is very limited.
METHODOLOGY/PRINCIPAL FINDINGS: We conducted longitudinal studies to investigate the entomological parameters of the simian malaria vectors and to examine the genetic diversity and evolutionary pattern of their simian Plasmodium. All the captured Anopheles mosquitoes were dissected to examine for the presence of oocysts, sporozoites and to determine the parous rate. Our study revealed that the Anopheles Leucosphyrus Group mosquitoes are highly potential competent vectors, as evidenced by their high rate of parity, survival and sporozoite infections in these mosquitoes. Thus, these mosquitoes represent a risk of human infection with zoonotic simian malaria in this region. Haplotype analysis on P. cynomolgi and P. inui, found in high prevalence in the Anopheles mosquitoes from this study, had shown close relationship between simian Plasmodium from the Anopheles mosquitoes with its vertebrate hosts. This directly signifies the ongoing transmission between the vector, macaques, and humans. Furthermore, population genetic analysis showed significant negative values which suggest that both Plasmodium species are undergoing population expansion.
CONCLUSIONS/SIGNIFICANCE: With constant microevolutionary processes, there are potential for both P. inui and P. cynomolgi to emerge and spread as a major public health problem, following the similar trend of P. knowlesi. Therefore, concerted vector studies in other parts of Southeast Asia are warranted to better comprehend the transmission dynamics of this zoonotic simian malaria which eventually would aid in the implementation of effective control measures in a rapidly changing environment.

Matched MeSH terms: Mosquito Vectors/parasitology
Fulltext The prevalence of simian malaria in wild long-tailed macaques throughout Peninsular Malaysia

Shahari S, Bin Abdullah ML, Binti Isman Rohimly AA, Binti Ashrat N, Amir A, Atroosh WMM, et al.

Sci Rep, 2024 Mar 12;14(1):6023.
PMID: 38472278 DOI: 10.1038/s41598-024-54981-2

The parasite Plasmodium knowlesi has been the sole cause of malaria in Malaysia from 2018 to 2022. The persistence of this zoonotic species has hampered Malaysia's progress towards achieving the malaria-free status awarded by the World Health Organisation (WHO). Due to the zoonotic nature of P. knowlesi infections, it is important to study the prevalence of the parasite in the macaque host, the long-tailed macaque (Macaca fascicularis). Apart from P. knowlesi, the long-tailed macaque is also able to harbour Plasmodium cynomolgi, Plasmodium inui, Plasmodium caotneyi and Plasmodium fieldi. Here we report the prevalence of the 5 simian malaria parasites in the wild long-tailed macaque population in 12 out of the 13 states in Peninsular Malaysia using a nested PCR approach targeting the 18s ribosomal RNA (18s rRNA) gene. It was found that all five Plasmodium species were widely distributed throughout Peninsular Malaysia except for states with major cities such as Kuala Lumpur and Putrajaya. Of note, Pahang reported a malaria prevalence of 100% in the long-tailed macaque population, identifying it as a potential hotspot for zoonotic transmission. Overall, this study shows the distribution of the 5 simian malaria parasite species throughout Peninsular Malaysia, the data of which could be used to guide future malaria control interventions to target zoonotic malaria.

Matched MeSH terms: Macaca fascicularis/parasitology
Mesocoelium malayanum sp. n. (Digenea: Brachycoeliidae) in a frog, Rana macrodon Dumeril and Bibron 1941, from Malaysia

Palmieri JR, Sullivan JT

J Helminthol, 1977 Sep;51(3):205-8.
PMID: 599267

Mesocoelium malayanum sp. n. is described from the frog Rana macrodon, in Malaysia. Elongate body, broader anteriorly, measuring 1.900 (1.679-2.070) mm long by 0.404 (0.380-0.437) wide, tegument aspinose oral sucker 0.212 (0.200-0.228) by 0.202 (9.191-0.205), acetabulum 0.141 (0.132-0.150) by 0.139 (0.123-0.146), prepharynx present, oesophagus 0.115 (0.096-0.137), caeca reaching posterior 1/3 of body, anterior testis 0.097 (0.087-0.110) by 0.091 (0.087-0.100) dorsal to acetabulum, posterior testis 0.094 (0.087-0.101) by 0.092 (0.091-0.100), cirrus pouch 0.121 (0.111-0.130) by 0.047 (0.041-0.055), genital pore at left of midline of oesophagus just anterior to intestinal bifurcation, ovary 0.110 (0.091-0.127) by 0.089 (0.085-0.096) on left of body and posterior to acetabulum, vitelline glands with single follicles extending from intestinal bifurcation to ends of caeca, excretory vesicle I-shaped and eggs 0.040 (0.037-0.046) by 0.023 (0.022-0.024). Although morphologically related to M. maroccanum and M. meggitti, M. malayanum is considered to be a new species.

Matched MeSH terms: Ranidae/parasitology*
Stunkardia minuta sp. n. (Trematoda: Paramphistomidae) from the Malayan box-tortoise Cuora amboinensis

Palmieri JR, Sullivan JT

J Helminthol, 1977 Jun;51(2):121-4.
PMID: 886177

Stunkardia minuta sp. n. was recovered from the small intestine and rectum of 5 box-tortoises (Cuora amboinensis) in Malaysia. The average body size (L X W) is 11-42 X 2-35 mm; oral sucker 1-51 X 1.02; oral pouches 0-21 X 0.18; ventral sucker 1-67 X 1-43; oesophageal bulb 0-54 X 0-54; ant. testis 0-95 X 0-98; post. testis 0-94 X 0.94; seminal vesicle 0-82 X 0-24; ootype 0-21 X 0-41; ovary 0-41 X 0-34; and egg 121 X 83 micrometer. Although morphologically similar to S. dilymphosa, S. minuta is distinct from any other reported member of the Paramphistomidae.

Matched MeSH terms: Turtles/parasitology*
Neodiplostomum (Conodiplostomum) ramachandrani sp. n. from Mueller's rat, Rattus muelleri in Malaysia

Betterton C

J Helminthol, 1976 Sep;50(3):157-61.
PMID: 993573

Neodiplostomum (Conodiplostomum) ramachandrani sp. n. is described from Rattus muelleri in Kepong, Selangor, Malaysia. It is characterised by having symmetrical dumbell-shaped testes, and vitellaria as a single ventral band in the hindbody. The taxonomic relations of Neodiplostomum, Conodiplostomum and Fibricola are discussed and possible significance of the fluke as an ecological indicator noted.

Matched MeSH terms: Rats/parasitology*
Selection of ssDNA aptamers and construction of aptameric electrochemical biosensor for the detection of Giardia intestinalis trophozoite protein

Alhindawi M, Rhouati A, Noordin R, Cialla-May D, Popp J, Zourob M

Int J Biol Macromol, 2024 May;267(Pt 2):131509.
PMID: 38608978 DOI: 10.1016/j.ijbiomac.2024.131509

Giardia intestinalis is one of the most widespread intestinal parasites and is considered a major cause of epidemic or sporadic diarrhea worldwide. In this study, we aimed to develop a rapid aptameric diagnostic technique for G. intestinalis infection. First, the SELEX (Systematic Evolution of Ligands by Exponential Enrichment) process generated DNA aptamers specific to a recombinant protein of the parasite's trophozoite. Ten selection rounds were performed; each round, the DNA library was incubated with the target protein conjugated to Sepharose beads. Then, the unbound sequences were removed by washing and the specific sequences were eluted and amplified by Polymerase Chain Reaction (PCR). Two aptamers were selected, and the dissociation constants (Kd), were determined as 2.45 and 16.95 nM, showed their high affinity for the G. intestinalis trophozoite protein. Subsequently, the aptamer sequence T1, which exhibited better affinity, was employed to develop a label-free electrochemical biosensor. A thiolated aptamer was covalently immobilized onto a gold screen-printed electrode (SPGE), and the binding of the targeted protein was monitored using square wave voltammetry (SWV). The developed aptasensor enabled accurate detection of the G. intestinalis recombinant protein within the range of 0.1 pg/mL to 100 ng/mL, with an excellent sensitivity (LOD of 0.35 pg/mL). Moreover, selectivity studies showed a negligible cross-reactivity toward other proteins such as bovine serum albumin, globulin, and G. intestinalis cyst protein.

Matched MeSH terms: Giardiasis/parasitology
Fulltext Anti-Acanthamoeba synergistic effect of chlorhexidine and Garcinia mangostana extract or α-mangostin against Acanthamoeba triangularis trophozoite and cyst forms

Sangkanu S, Mitsuwan W, Mahabusarakam W, Jimoh TO, Wilairatana P, Girol AP, et al.

Sci Rep, 2021 Apr 13;11(1):8053.
PMID: 33850179 DOI: 10.1038/s41598-021-87381-x

Acanthamoeba spp. can cause amoebic keratitis (AK). Chlorhexidine is effective for AK treatment as monotherapy, but with a relative failure on drug bioavailability in the deep corneal stroma. The combination of chlorhexidine and propamidine isethionate is recommended in the current AK treatment. However, the effectiveness of treatment depends on the parasite and virulence strains. This study aims to determine the potential of Garcinia mangostana pericarp extract and α-mangostin against Acanthamoeba triangularis, as well as the combination with chlorhexidine in the treatment of Acanthamoeba infection. The minimal inhibitory concentrations (MICs) of the extract and α-mangostin were assessed in trophozoites with 0.25 and 0.5 mg/mL, for cysts with 4 and 1 mg/mL, respectively. The MIC of the extract and α-mangostin inhibited the growth of A. triangularis trophozoites and cysts for up to 72 h. The extract and α-mangostin combined with chlorhexidine demonstrated good synergism, resulting in a reduction of 1/4-1/16 of the MIC. The SEM results showed that Acanthamoeba cells treated with a single drug and its combination caused damage to the cell membrane and irregular cell shapes. A good combination displayed by the extract or α-mangostin and chlorhexidine, described for the first time. Therefore, this approach is promising as an alternative method for the management of Acanthamoeba infection in the future.

Matched MeSH terms: Acanthamoeba Keratitis/parasitology
Fulltext Association between Landscape Factors and Spatial Patterns of Plasmodium knowlesi Infections in Sabah, Malaysia

Fornace KM, Abidin TR, Alexander N, Brock P, Grigg MJ, Murphy A, et al.

Emerg Infect Dis, 2016 Feb;22(2):201-8.
PMID: 26812373 DOI: 10.3201/eid2202.150656

The zoonotic malaria species Plasmodium knowlesi has become the main cause of human malaria in Malaysian Borneo. Deforestation and associated environmental and population changes have been hypothesized as main drivers of this apparent emergence. We gathered village-level data for P. knowlesi incidence for the districts of Kudat and Kota Marudu in Sabah state, Malaysia, for 2008-2012. We adjusted malaria records from routine reporting systems to reflect the diagnostic uncertainty of microscopy for P. knowlesi. We also developed negative binomial spatial autoregressive models to assess potential associations between P. knowlesi incidence and environmental variables derived from satellite-based remote-sensing data. Marked spatial heterogeneity in P. knowlesi incidence was observed, and village-level numbers of P. knowlesi cases were positively associated with forest cover and historical forest loss in surrounding areas. These results suggest the likelihood that deforestation and associated environmental changes are key drivers in P. knowlesi transmission in these areas.

Matched MeSH terms: Malaria/parasitology*
An improved stool concentration procedure for the detection of Cryptosporidium oocysts in Orang Asli stool samples

Salleh FM, Moktar N, Yasin AM, Al-Mekhlafi HM, Anuar TS

J Microbiol Methods, 2014 Nov;106:143-145.
PMID: 25193442 DOI: 10.1016/j.mimet.2014.08.019

To improve the stool concentration procedure, we modified different steps of the standard formalin-ether concentration technique and evaluated these modifications by examining stool samples collected in the field. Seven samples were found positive by the modified formalin-ether concentration technique (M-FECT). Therefore, the M-FECT procedure provides enhanced detection of Cryptosporidium oocysts.

Matched MeSH terms: Feces/parasitology*; Parasitology/methods*
The prevalence and distribution of gastrointestinal parasites of stray and refuge dogs in four locations in India

Traub RJ, Pednekar RP, Cuttell L, Porter RB, Abd Megat Rani PA, Gatne ML

Vet Parasitol, 2014 Sep 15;205(1-2):233-8.
PMID: 25139393 DOI: 10.1016/j.vetpar.2014.06.037

A gastrointestinal parasite survey of 411 stray and refuge dogs sampled from four geographical and climactically distinct locations in India revealed these animals to represent a significant source of environmental contamination for parasites that pose a zoonotic risk to the public. Hookworms were the most commonly identified parasite in dogs in Sikkim (71.3%), Mumbai (48.8%) and Delhi (39.1%). In Ladakh, which experiences harsh extremes in climate, a competitive advantage was observed for parasites such as Sarcocystis spp. (44.2%), Taenia hydatigena (30.3%) and Echinococcus granulosus (2.3%) that utilise intermediate hosts for the completion of their life cycle. PCR identified Ancylostoma ceylanicum and Ancylostoma caninum to occur sympatrically, either as single or mixed infections in Sikkim (Northeast) and Mumbai (West). In Delhi, A. caninum was the only species identified in dogs, probably owing to its ability to evade unfavourable climatic conditions by undergoing arrested development in host tissue. The expansion of the known distribution of A. ceylanicum to the west, as far as Mumbai, justifies the renewed interest in this emerging zoonosis and advocates for its surveillance in future human parasite surveys. Of interest was the absence of Trichuris vulpis in dogs, in support of previous canine surveys in India. This study advocates the continuation of birth control programmes in stray dogs that will undoubtedly have spill-over effects on reducing the levels of environmental contamination with parasite stages. In particular, owners of pet animals exposed to these environments must be extra vigilant in ensuring their animals are regularly dewormed and maintaining strict standards of household and personal hygiene.

Matched MeSH terms: Dog Diseases/parasitology*; Gastrointestinal Diseases/parasitology; Parasitic Diseases, Animal/parasitology*
New species of Bakeria (Nematoda; Strongylida; Molineidae), new species of Falcaustra (Nematoda; Ascaridida; Kathlaniidae) and other helminths in Cnemaspis mcguirei (Sauria; Gekkonidae) from Peninsular Malaysia

Bursey CR, Goldberg SR, Grismer LL

Acta Parasitol, 2014 Oct;59(4):643-52.
PMID: 25236275 DOI: 10.2478/s11686-014-0299-y

Two new nematode species, Bakeria schadi sp. nov. and Falcaustra malaysiaia sp. nov. from the gastrointestinal tract of McGuire's rock gecko, Cnemaspis mcguirei (Sauria: Gekkonidae) collected in Peninsular Malaysia are described. The two species now assigned to Bakeria are separated on the bases of male bursa type and location of the excretory pore: type II in B. schadi sp. nov. and type I in B. bakeri; location of excretory pore, anterior to nerve ring in B. schadi sp. nov. and posterior to nerve ring in B. bakeri. Falcaustra malaysiaia sp. nov. is most similar to F. chabaudi, F. concinnae, F. condorcanquii, F. barbi, F. dubia, and F. tchadi in that these 7 species possess 1 pseudosucker, 1 median papilla plus 10 pairs caudal papillae, and spicules with lengths between 1 and 2 mm. F. barbi and F. tchadi lack adcloacal papillae; the remaining 5 species possess 1 pair of adcloacal papillae. Falcaustra chabaudi is known from Nearctic salamanders; F. concinnae from Nearctic turtles; F. condorcanquii from Neotropical frogs, F. dubia from Oriental frogs, and F. malaysiaia sp. nov. from Oriental geckos. Two additional species of Nematoda were found, Cosmocerca ornata and Meteterakis singaporensis. Cnemaspis mcguirei represents a new host record for Cosmocerca ornata and Meteterakis singaporensis.

Matched MeSH terms: Gastrointestinal Diseases/parasitology; Helminthiasis, Animal/parasitology*; Lizards/parasitology*
Fulltext Sarcocystis nesbitti causes acute, relapsing febrile myositis with a high attack rate: description of a large outbreak of muscular sarcocystosis in Pangkor Island, Malaysia, 2012

Italiano CM, Wong KT, AbuBakar S, Lau YL, Ramli N, Syed Omar SF, et al.

PLoS Negl Trop Dis, 2014 May;8(5):e2876.
PMID: 24854350 DOI: 10.1371/journal.pntd.0002876

From the 17th to 19th January 2012, a group of 92 college students and teachers attended a retreat in a hotel located on Pangkor Island, off the west coast of Peninsular Malaysia. Following the onset of symptoms in many participants who presented to our institute, an investigation was undertaken which ultimately identified Sarcocystis nesbitti as the cause of this outbreak.

Matched MeSH terms: Fever/parasitology; Myositis/parasitology; Sarcocystosis/parasitology

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