Displaying publications 61 - 80 of 1452 in total

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  1. First Report of Lecanicephalidean Tapeworms (Eucestoda) from Freshwater, Including Description of Three New Species of Tetragonocephalum Shipley and Hornell, 1905
    Jensen K, Guyer R
    J Parasitol, 2021 01 01;107(1):1-15.
    PMID: 33429430 DOI: 10.1645/19-167
    The lecanicephalidean cestodes parasitizing the spiral intestine of the endangered giant freshwater whipray, Urogymnus polylepis (Bleeker), are investigated for the first time. Eight host specimens were collected between 2002 and 2008 at 2 collecting sites off the eastern coast of Borneo: 6 from the Kinabatangan River (Malaysia) and 2 from a fish market in Tarakan (Indonesia). Two of these individuals were found to be infected with a total of 3 new species of TetragonocephalumShipley and Hornell, 1905. Tetragonocephalum georgei n. sp. and Tetragonocephalum opimum n. sp. were recovered from a host specimen from the Kinabatangan River, and Tetragonocephalum levicorpum n. sp. was found parasitizing a host specimen purchased at a fish market in Tarakan. Specimens of each of the new species were prepared for light microscopy; specimens of 2 of the new species were prepared for scanning electron microscopy, and histological sections were prepared for 1 of the new species. The 3 new species are distinct from the 9 valid species of Tetragonocephalum and the 1 species inquirendum based on, for example, total length, number of proglottids and testes, and size of the scolex and acetabula. Tetragonocephalum georgei n. sp. and T. levicorpum n. sp. are unusual among their congeners in that they are euapolytic (i.e., gravid proglottids were not observed) rather than apolytic. They differ from one another in scolex and acetabula size. Tetragonocephalum opimum n. sp. is unusual among its congeners in its possession of vitelline follicles arranged in 2, rather than 3, regions in the proglottid. These new species increase the total number of valid species of Tetragonocephalum to 12 and the total number of known cestodes from U. polylepis to 13 species across 6 genera in 4 orders. This is the first account of lecanicephalideans reported from freshwater. The taxonomic status of each of the 32 nominal taxa historically associated with Tetragonocephalum is re-assessed. Type host identities of all valid species are revised and discussed in light of recent taxonomic efforts in the Dasyatidae Jordan and Gilbert.
    Matched MeSH terms: Cestode Infections/parasitology; Fish Diseases/parasitology*; Fresh Water/parasitology*; Intestines/parasitology; Skates (Fish)/parasitology*; Rivers/parasitology
  2. Direct detection of Strongyloides infection via molecular and antigen detection methods
    Balachandra D, Ahmad H, Arifin N, Noordin R
    Eur J Clin Microbiol Infect Dis, 2021 Jan;40(1):27-37.
    PMID: 32729057 DOI: 10.1007/s10096-020-03949-x
    Laboratory diagnosis of Strongyloides infections can be grouped into direct and indirect detection methods, and a combination of the two methods is often needed to reach an accurate and timely diagnosis. This review focuses on non-conventional direct detection via molecular and antigen detection assays. Conventional PCR is the most commonly used molecular diagnostic for Strongyloides. Real-time PCR is accurate and highly sensitive for quantitative and qualitative analysis. Meanwhile, PCR-RFLP can efficiently distinguish human and dog isolates of S. stercoralis, S. fuelleborni (from monkey), and S. ratti (from rodent). Loop-mediated isothermal amplification (LAMP) amplifies DNA isothermally with high specificity, efficiency, and rapidity, and has potential for point-of-care (POC) translation. As for antigen detection assay, coproantigen detection ELISAs for strongyloidiasis traditionally relied on raising rabbit polyclonal antibodies against the parasite antigens for use as capture or detection reagents. Subsequently, hybridoma technology using animals has enabled the discovery of monoclonal antibodies specific to Strongyloides antigens and was utilised to develop antigen detection assays. In recent times, phage display technology has facilitated the discovery of scFv antibody against Strongyloides protein that can accelerate the development of such assays. Improvements in both direct detection methods are being made. Strongyloides molecular diagnostics is moving from the detection of a single infection to the simultaneous detection of soil-transmitted helminths. Meanwhile, antigen detection assays can also be multiplexed and aptamers can be used as antigen binders. In the near future, these two direct detection methods may be more widely used as diagnostic tools for strongyloidiasis.
    Matched MeSH terms: Strongyloidiasis/parasitology
  3. 'Targeting the feast of a sleeping beast': Nutrient and mineral dependencies of encysted Acanthamoeba castellanii
    Baig AM, Khan NA, Katyara P, Lalani S, Baig R, Nadeem M, et al.
    Chem Biol Drug Des, 2021 01;97(1):18-27.
    PMID: 32602961 DOI: 10.1111/cbdd.13755
    Acanthamoeba spp. cause a corneal infection, Acanthamoeba keratitis (AK), and a cerebral infection, granulomatous amoebic encephalitis (GAE). Though aggressive chemotherapy has been able to kill the active trophozoite form of Acanthamoeba, the encysted form of this parasite has remained problematic to resist physiological concentrations of drugs. The emergence of encysted amoeba into active trophozoite form poses a challenge to eradicate this parasite. Acanthamoeba trophozoites have active metabolic machinery that furnishes energy in the form of ATPs by subjecting carbohydrates and lipids to undergo pathways including glycolysis and beta-oxidation of free fatty acids, respectively. However, very little is known about the metabolic preferences and dependencies of an encysted trophozoite on minerals or potential nutrients that it consumes to live in an encysted state. Here, we investigate the metabolic and nutrient preferences of the encysted trophozoite of Acanthamoeba castellanii and the possibility to target them by drugs that act on calcium ion dependencies of the encysted amoeba. The experimental assays, immunostaining coupled with bioinformatics tools show that the encysted Acanthamoeba uses diverse nutrient pathways to obtain energy in the quiescent encysted state. These findings highlight potential pathways that can be targeted in eradicating amoebae cysts successfully.
    Matched MeSH terms: Keratitis/parasitology
  4. Fulltext Prevalence of simian malaria parasites in macaques of Singapore
    Li MI, Mailepessov D, Vythilingam I, Lee V, Lam P, Ng LC, et al.
    PLoS Negl Trop Dis, 2021 Jan;15(1):e0009110.
    PMID: 33493205 DOI: 10.1371/journal.pntd.0009110
    Plasmodium knowlesi is a simian malaria parasite currently recognized as the fifth causative agent of human malaria. Recently, naturally acquired P. cynomolgi infection in humans was also detected in Southeast Asia. The main reservoir of both parasites is the long-tailed and pig-tailed macaques, which are indigenous in this region. Due to increased urbanization and changes in land use, there has been greater proximity and interaction between the long-tailed macaques and the general population in Singapore. As such, this study aims to determine the prevalence of simian malaria parasites in local macaques to assess the risk of zoonosis to the general human population. Screening for the presence of malaria parasites was conducted on blood samples from 660 peridomestic macaques collected between Jan 2008 and Mar 2017, and 379 wild macaques collected between Mar 2009 and Mar 2017, using a Pan-Plasmodium-genus specific PCR. Positive samples were then screened using a simian Plasmodium species-specific nested PCR assay to identify the species of parasites (P. knowlesi, P. coatneyi, P. fieldi, P. cynomolgi, and P. inui) present. All the peridomestic macaques sampled were tested negative for malaria, while 80.5% of the 379 wild macaques were infected. All five simian Plasmodium species were detected; P. cynomolgi being the most prevalent (71.5%), followed by P. knowlesi (47.5%), P. inui (42.0%), P. fieldi (32.5%), and P. coatneyi (28.5%). Co-infection with multiple species of Plasmodium parasites was also observed. The study revealed that Singapore's wild long-tailed macaques are natural hosts of the five simian malaria parasite species, while no malaria was detected in all peridomestic macaques tested. Therefore, the risk of simian malaria transmission to the general human population is concluded to be low. However, this can be better demonstrated with the incrimination of the vectors of simian malaria parasites in Singapore.
    Matched MeSH terms: Macaca/parasitology*; Macaca fascicularis/parasitology; Monkey Diseases/parasitology*
  5. Fulltext Nutritional status, hemoglobin level and their associations with soil-transmitted helminth infections between Negritos (indigenous) from the inland jungle village and resettlement at town peripheries
    Muslim A, Lim YA, Mohd Sofian S, Shaari SA, Mohd Zain Z
    PLoS One, 2021;16(1):e0245377.
    PMID: 33439889 DOI: 10.1371/journal.pone.0245377
    This study compared the current nutritional status, hemoglobin levels and their associations with soil-transmitted helminth (STH) infections between two categories of Negritos (indigenous): (i) Inland Jungle Villages (IJV) (ii) and Resettlement Plan Scheme (RPS) near town peripheries, decades after redevelopment and demarginalization. A total of 416 Negritos (IJV: 149; RPS: 267) was included for nutritional profiling based on anthropometric analysis. However, only 196 (IJV: 64; RPS: 132) individuals consented to blood taking for the hemoglobin (Hb) measurements. Subsequently, the association of undernutrition and anemia with STH infections were determined based on univariate and multivariate logistic regression analyses. The overall prevalence of stunting, wasting, and underweight amongst children and adolescents (n = 343) were 45.8%, 42.3% and 59.1%, respectively. In adults (n = 73), the prevalence of underweight was low (6.8%) but overweight and obese was prominent (26.0%). For anemia (n = 196), an overall prevalence rate of 68.4% were observed with 80% and 70.4% of children aged 2-6 y/o and aged 7-12 y/o, respectively being anemic. Comparatively, the prevalence of underweight (WAZ) was significantly higher in the RPS versus the IJV (P = 0.03) In the IJV, children aged ≤ 6 y/o and having STH poly-parasitism were associated with underweight (P = 0.01) and moderate-severe T. trichiura infection was associated with anemia. Whilst in the RPS, underweight was highly associated with only T. trichiura infection (P = 0.04). Wasting was significantly associated with young children aged ≤10 in both IJV (P = 0.004) and RPS (P = 0.02). Despite efforts in improving provision of facilities and amenities among the indigenous, this study highlighted a high magnitude of nutritional issues among the Negritos especially those in the RPS and their likely association with STH infections and decades of demarginalization. Joint nutritional intervention strategies with mass anti-helminthic treatment are imperative and urgently needed to reduce the undernutrition problems especially among indigenous children.
    Matched MeSH terms: Soil/parasitology*
  6. Fulltext Risk factor of plasmodium knowlesi infection in Sabah Borneo Malaysia, 2020: A population-based case-control study
    Chin AZ, Avoi R, Atil A, Awang Lukman K, Syed Abdul Rahim SS, Ibrahim MY, et al.
    PLoS One, 2021;16(9):e0257104.
    PMID: 34506556 DOI: 10.1371/journal.pone.0257104
    BACKGROUND: In the Malaysian state of Sabah, P. knowlesi notifications increased from 2% (59/2,741) of total malaria notifications in 2004 to 98% (2030/2,078) in 2017. There was a gap regarding P. knowlesi acquisition risk factors related to practice specifically in working age group. The main objective of this study was to identify the risk factors for acquiring P. knowlesi infection in Sabah among the working age group.

    METHODS AND METHODS: This retrospective population-based case-control study was conducted in Ranau district to assess sociodemographic, behavioural and medical history risk factors using a pretested questionnaire. The data were entered and analyzed using IBM SPSS version 23. Bivariate analysis was conducted using binary logistic regression whereas multivariate analysis was conducted using multivariable logistic regression. We set a statistical significance at p-value less than or equal to 0.05.

    RESULTS: A total of 266 cases and 532 controls were included in the study. Male gender (AOR = 2.71; 95% CI: 1.63-4.50), spending overnight in forest (AOR = 1.92; 95% CI: 1.20-3.06), not using mosquito repellent (AOR = 2.49; 95% CI: 1.36-4.56) and history of previous malaria infection (AOR = 49.34; 95% CI: 39.09-78.32) were found to be independent predictors of P. knowlesi infection.

    CONCLUSIONS: This study showed the need to strengthen the strategies in preventing and controlling P. knowlesi infection specifically in changing the practice of spending overnight in forest and increasing the usage of personal mosquito repellent.

    Matched MeSH terms: Malaria/parasitology*
  7. Fulltext Antiparasitic potential of Nephrolepis biserrata methanol extract against the parasitic leech Zeylanicobdella arugamensis (Hirudinea) and LC-QTOF analysis
    Shah MD, Venmathi Maran BA, Haron FK, Ransangan J, Ching FF, Shaleh SRM, et al.
    Sci Rep, 2020 12 16;10(1):22091.
    PMID: 33328532 DOI: 10.1038/s41598-020-79094-4
    Marine leech Zeylanicobdella arugamensis (Piscicolidae), an economically important parasite is infesting predominantly cultured groupers, hybrid groupers and other fish in Southeast Asian countries. In this study, we tested the anti-parasitic potential of a medicinal plant Nephrolepis biserrata found in Sabah, East Malaysia against Z. arugamensis. Various concentrations of methanol extracts of the plant were tested experimentally against Z. arugamensis and disinfestation of the leech from its primary host hybrid groupers. The composition of methanol extract of N. biserrata was determined through LC-QTOF analysis. The significant anti-parasitic activity of 100% mortality of leeches was observed with the exposure of N. biserrata extracts. The average time to kill the leeches at concentrations of 25, 50 and 100 mg/ml was 25.11 ± 3.26, 11.91 ± 0.99, and 4.88 ± 0.50 min., respectively. Further, at various low concentrations of N. biserrata 2.5, 5 and 10 mg/ml, hybrid groupers were disinfested in an average time of 108.33 ± 12.65, 65.83 ± 9.70 and 29.16 ± 5.85 min., respectively. The tandem mass spectrometry data from LC-QTOF indicated some hits on useful bioactive compounds such as terpenoids (ivalin, isovelleral, brassinolide, and eschscholtzxanthin), flavonoids (alnustin, kaempferol 7,4'-dimethyl ether, and pachypodol), phenolics (piscidic acid, chlorogenic acid, and ankorine), and aromatic (3-hydroxycoumarin). Thus N. biserrata can act as a potential biocontrol agent.
    Matched MeSH terms: Ectoparasitic Infestations/parasitology; Fishes/parasitology
  8. Fulltext Massive airway myiasis: an extreme rarity
    Teah MK, Chu YM, Shanmuganathan SD, Yeap TB
    BMJ Case Rep, 2020 Dec 09;13(12).
    PMID: 33298493 DOI: 10.1136/bcr-2020-237764
    Intubations are important live saving skills to maintain adequate ventilation and oxygenation. Common indications include impending upper airway obstruction, respiratory failure and impaired conscious level. Oral myiasis is an infrequently found disease which is characterised by ectoparasitic infestation of body tissues by fly maggots.We present a case report and share valuable experiences on a patient with massive airway myiasis causing upper airway obstruction which require emergency intubation.
    Matched MeSH terms: Mouth Diseases/parasitology*; Myiasis/parasitology*
  9. Detection and molecular identification of Leucocytozoon and Plasmodium species from village chickens in different areas of Myanmar
    Win SY, Chel HM, Hmoon MM, Htun LL, Bawm S, Win MM, et al.
    Acta Trop, 2020 Dec;212:105719.
    PMID: 32976841 DOI: 10.1016/j.actatropica.2020.105719
    Village chicken production, a traditional, small-scale, and extensive backyard poultry industry, has been profitable for local farmers in Myanmar. However, there is scanty information available concerning the infection of these chickens with avian pathogens, including haemoprotozoan parasites. In the present study, we provide the first report of microscopic detection and molecular identification of Leucocytozoon and Plasmodium parasites from seven different areas of Myanmar. Leucocytozoon gametocytes were detected in 17.6% (81/461) of the blood smears from village chickens. The nested polymerase chain reaction (PCR) for targeting Leucocytozoon mitochondrial cytochrome b (cyt b) genes had a 17.6% positive rate. Although the positive rate of nested PCR targeting Plasmodium/Haemoproteus cyt b was 34.3%, the PCR protocol was observed to possibly amplify DNA of a certain species of Leucocytozoon. There were no obvious clinical signs in the infected birds. Statistical analysis of the microscopic detection and PCR detection rates using the age and sex of birds as internal factors revealed that the statistical significances differed according to the study area. The sequencing of 32 PCR products obtained from each study area revealed infection by Leucocytozoon caulleryi in three birds, Leucocytozoon sabrazesi in two birds, Leucocytozoon schoutedeni in two birds, Leucocytozoon sp. in eighteen birds, and Plasmodium juxtanucleare in seven birds; however, Haemoproteus infection was not detected. While L. sabrazesi was detected in chickens from the central region of Myanmar, the other haemosporidians were detected in those from different areas. In the haplotype analysis, we detected 17 haemosporidian cyt b haplotypes, including two for L. caulleryi, one for L. sabrazesi, two for L. schoutedeni, nine for Leucocytozoon sp., and three for P. juxtanucleare. Phylogenetic analysis of the cyt b haplotypes revealed a considerably close genetic relationship among chicken haemosporidians detected in Myanmar, Thailand, and Malaysia. These results indicate that well-recognized widespread species of chicken Leucocytozoon and Plasmodium are distributed nationwide in Myanmar, providing new insights into the ecosystem and control strategies of haemosporidian parasites in domesticated chickens in Myanmar.
    Matched MeSH terms: Chickens/parasitology*
  10. Fulltext Plasmodium knowlesi infecting humans in Southeast Asia: What's next?
    Jeyaprakasam NK, Liew JWK, Low VL, Wan-Sulaiman WY, Vythilingam I
    PLoS Negl Trop Dis, 2020 12;14(12):e0008900.
    PMID: 33382697 DOI: 10.1371/journal.pntd.0008900
    Plasmodium knowlesi, a simian malaria parasite, has been in the limelight since a large focus of human P. knowlesi infection was reported from Sarawak (Malaysian Borneo) in 2004. Although this infection is transmitted across Southeast Asia, the largest number of cases has been reported from Malaysia. The increasing number of knowlesi malaria cases has been attributed to the use of molecular tools for detection, but environmental changes including deforestation likely play a major role by increasing human exposure to vector mosquitoes, which coexist with the macaque host. In addition, with the reduction in human malaria transmission in Southeast Asia, it is possible that human populations are at a greater risk of P. knowlesi infection due to diminishing cross-species immunity. Furthermore, the possibility of increasing exposure of humans to other simian Plasmodium parasites such as Plasmodium cynomolgi and Plasmodium inui should not be ignored. We here review the current status of these parasites in humans, macaques, and mosquitoes to support necessary reorientation of malaria control and elimination in the affected areas.
    Matched MeSH terms: Malaria/parasitology; Monkey Diseases/parasitology
  11. Molecular detection of tick-borne haemopathogens in shelter dogs and Rhipicephalus sanguineus (sensu lato) ticks from Peninsular Malaysia
    Sipin Q, Mustaffa Kamal F, Watanabe M, Megat Abdul Rani PA, Low VL, Abdul Aziz NA
    Comp Immunol Microbiol Infect Dis, 2020 Dec;73:101563.
    PMID: 33120297 DOI: 10.1016/j.cimid.2020.101563
    Ticks are important vectors in transmitting various pathogens and they could jeopardize the health and welfare of humans and animals worldwide. The present study aimed to investigate the presence of important tick-borne haemopathogens (TBH) in dogs and ticks via polymerase chain reaction (PCR) assays. A total of 220 blood samples and 140 ticks were collected from 10 animal shelters in Peninsular Malaysia. Of 220 blood samples, 77 (35 %) were positive to TBH, of which 20 % were E. canis, 12 % were A. platys, 7 % were B. gibsoni and 7 % were B. vogeli. All ticks were identified as Rhipicephalus sanguineus with five samples (3.57 %) positive with TBH. Co-infections of TBH (0.45-9.55 %) in dogs were also observed in this study.
    Matched MeSH terms: Dog Diseases/parasitology
  12. Purification of Plasmodium and Babesia- infected erythrocytes using a non-woven fabric filter
    Tao ZY, Liu WP, Dong J, Feng XX, Yao DW, Lv QL, et al.
    Trop Biomed, 2020 Dec 01;37(4):911-918.
    PMID: 33612745 DOI: 10.47665/tb.37.4.911
    The purification of parasite-infected erythrocytes from whole blood containing leucocytes is crucial for many downstream genetic and molecular assays in parasitology. Current methodologies to achieve this are often costly and time consuming. Here, we demonstrate the successful application of a cheap and simple Non-Woven Fabric (NWF) filter for the purification of parasitized red blood cells from whole blood. NWF filtration was applied to the malaria-parasitized blood of three strains of mice, and one strain of rat, and to Babesia gibsoni parasitized dog blood. Before and after filtration, the white blood cell (WBC) removal rates and red blood cell (RBC) recovery rates were measured. After NWF filter treatment of rodent malaria-infected blood, the WBC removal rates and RBC recovery rates were, for Kunming mice: 99.51%±0.30% and 86.12%±8.37%; for BALB/C mice: 99.61%±0.15% and 80.74%±7.11%; for C57 mice: 99.71%±0.12% and 84.87%±3.83%; for Sprague-Dawley rats: 99.93%±0.03% and 83.30%±2.96%. Microscopy showed WBCs were efficiently removed from infected dog blood samples, and there was no obvious morphological change of B. gibsoni parasites. NWF filters efficiently remove leukocytes from malaria parasite-infected mouse and rat blood, and are also suitable for filtration of B. gibsoni-infected dog blood.
    Matched MeSH terms: Erythrocytes/parasitology*
  13. Hemoprotozoa and Anaplasma spp. in rodents and shrews of Bangladesh
    Islam S, Rahman MK, Ferdous J, Rahman M, Akter S, Faraque MO, et al.
    Trop Biomed, 2020 Dec 01;37(4):842-851.
    PMID: 33612737 DOI: 10.47665/tb.37.4.842
    Hemoprotozoans are important pathogens of animals and humans, among which some species have zoonotic significance. The prevalence of different hemoprotozoa and Anaplasma spp. in larger mammals have been reported from different regions of the world. But, very few studies have been conducted to estimate the prevalence of hemoprotozoa in rodents and shrews of South-East Asia. The study assessed the prevalence of hemoprotozoa and Anaplasma spp. in rodents and shrews of Bangladesh. Blood samples (n=451) were collected from rodents and shrews between June 2011 and June 2013 and July-December 2015 from 4 land gradients of Bangladesh. Giemsa-stained blood smears revealed that 13% of animals were harboring hemoprotozoa (4.7% Babesia spp., 0.67% Plasmodium spp.), and Anaplasma spp. (7.5%). The study may serve as a guide for future hemoparasitic research of rodents and shrews.
    Matched MeSH terms: Rodentia/parasitology*; Shrews/parasitology*
  14. Helminthic parasites in indigenous chickens in Penang Island, Malaysia
    Farah Haziqah MT, Khadijah S
    Trop Biomed, 2020 Dec 01;37(4):896-902.
    PMID: 33612743 DOI: 10.47665/tb.37.4.896
    Indigenous chicken (Gallus domesticus) is reared for both its meat and eggs. Most consumers prefer the meat probably due to its specific texture and taste. The study was conducted to determine the presence of helminth parasites of 240 indigenous chickens (Gallus domesticus) obtained randomly from 12 divisions in Penang Island, Malaysia. Necropsy findings revealed 14 endoparasite species which parasitized these chickens namely, Acuaria hamulosa, Acuaria spiralis, Amoebotaenia sphenoides, Ascaridia galli, Brachylaima sp., Capillaria spp., Gongylonema ingluvicola, Heterakis gallinarum, Hymenolepis sp., Oxyspirura mansoni, Raillietina echinobothrida, Raillietina tetragona, Syngamus trachea and Tetrameres americana. The high abundance of helminth species observed in this study may be attributed to the free-range scavenging production system, where these indigenous chickens were exposed to intermediate or paratenic hosts of helminths which infect poultry. Besides, sustainable methods of helminthic control measure are necessary in order to enhance indigenous chicken production and eventually improve the economy of the rural farmers.
    Matched MeSH terms: Chickens/parasitology*; Helminthiasis, Animal/parasitology*; Poultry Diseases/parasitology*
  15. Morphological characteristics of microfilariae in blood smears of the common treeshrew Tupaia glis (Mammalia: Scandentia) in Gemas, Negeri Sembilan, Malaysia
    Mat Udin AS, Uni S, Zainuri NA, Abdullah Halim MR, Belabut DA
    Trop Biomed, 2020 Dec 01;37(4):1152-1157.
    PMID: 33612768 DOI: 10.47665/tb.37.4.1152
    Some filarial nematodes, such as Wuchereria bancrofti, Brugia malayi, and Brugia timori, cause lymphatic diseases in humans in the tropics, whereas other filarial parasites from wild animals cause zoonotic diseases in humans worldwide. To elucidate the prevalence and diversity of filarial parasites in Malaysia, we investigated the filarial parasites from wild animals in Gemas, Negeri Sembilan. To find adult filarial parasites, we dissected 26 animals, which included five frogs, one skink, one snake, two birds, six common treeshrews, and 11 rats. Then, we examined microfilariae in the blood smears and skin snips obtained from each animal. We found two types of microfilariae in the blood smears of common treeshrews: one was very similar to Malayfilaria sofiani and the other closely resembled Brugia tupaiae. These findings indicate an additional distribution of these filarial parasites in Gemas.
    Matched MeSH terms: Tupaia/parasitology*
  16. Trichinella spiralis: RNAi-mediated silencing of serine protease results in reduction of intrusion, development and fecundity
    Yang DQ, Zeng Y, Sun XY, Yue X, Hu CX, Jiang P, et al.
    Trop Biomed, 2020 Dec 01;37(4):932-946.
    PMID: 33612747 DOI: 10.47665/tb.37.4.932
    In previous studies, a Trichinella spiralis serine protease (TsSP) was identified in excretion/secretion (ES) products from intestinal infective L1 larvae (IIL1) using immunoproteomics. The complete cDNA sequence of TsSP gene was 1372 bp, which encoded 429 amino acids with 47.55 kDa. The TsSP was transcribed and expressed at all T. spiralis life cycle phases, as well as mainly located at the cuticle and stichosome of the parasitic nematode. Recombinant TsSP bind to intestinal epithelial cells (IEC) and promoted larva invasion, however, its exact function in invasion, development and reproduction are still unknown. The aim of this study was to confirm the biological function of TsSP during T. spiralis invasion and growth using RNA interference (RNAi) technology. The results showed that on 1 day after electroporation using 2.5 µM siRNA156, TsSP mRNA and protein expression of muscle larvae (ML) was suppressed by 48.35 and 59.98%, respectively. Meanwhile, silencing of TsSP gene by RNAi resulted in a 61.38% decrease of serine protease activity of ML ES proteins, and a significant reduction of the in vitro and in vivo invasive capacity of IIL1 to intrude into the IEC monolayer and intestinal mucosa. When mice were infected with siRNA 156-transfected larvae, adult worm and muscle larva burdens were decreased by 58.85 and 60.48%, respectively. Moreover, intestinal worm growth and female fecundity were evidently inhibited after TsSP gene was knockdown, it was demonstrated that intestinal adults became smaller and the in vitro newborn larval yield of females obviously declined compared with the control siRNA group. The results indicated that knockdown of TsSP gene by RNAi significantly reduced the TsSP expression and enzymatic activity, impaired larvae intrusion and growth, and lowered the female reproductive capacity, further verified that TsSP might participate in diverse processes of T. spiralis life cycle, it will be a new prospective candidate molecular target of anti-Trichinella vaccines.
    Matched MeSH terms: Intestinal Mucosa/parasitology
  17. Giardia duodenalis pathogenicity on immunosuppressed animal model
    Wakid MH, Toulah FH, Mahjoub HA, Alsulami MN, Hikal WM
    Trop Biomed, 2020 Dec 01;37(4):1008-1017.
    PMID: 33612753 DOI: 10.47665/tb.37.4.1008
    Giardiasis is the major water-borne diarrheal disease present worldwide caused by the common intestinal parasite, Giardia duodenalis. This work aims to investigate the effect of G. duodenalis infection pathogenicity in immunosuppressed animals through histopathological examination. A total of 45 BALB/c mice were divided into four groups; G1 (negative control), G2 (healthy animals exposed to Giardia); G3 (immunosuppressed animals exposed to Giardia), and G4 (non-exposed immunosuppressed animals). Our study revealed that G3 was the most affected group with an infection rate of 100%. The animals showed general weakness, soft stool, and high death rate with severe histopathological changes in the duodenum and mild degenerative changes in hepatic tissues. In G2, the maximal lesions in both duodenum and liver were on the 11th day. We spotted damage in the villi, edema in the central core, and submucosa, in addition to increased cellular infiltration with inflammation in lamina propria. The presence of the parasites within the villi and the lumen was clear. Most of the hepatocytes revealed hydropic and fatty changes, also dilated congested central veins and edema were observed. G3 changes were more intense than G2 with massive Giardia trophozoites between the intestinal villi, lumen, and extensive fatty liver degeneration. Immune suppression plays a significant role in the severity of injury with the Giardia parasites in duodenum and liver cells.
    Matched MeSH terms: Duodenum/parasitology; Intestinal Mucosa/parasitology; Liver/parasitology
  18. Fulltext Multi-Laboratory Evaluation of a Lateral Flow Rapid Test for Detection of Amebic Liver Abscess
    Noordin R, Yunus MH, Saidin S, Mohamed Z, Fuentes Corripio I, Rubio JM, et al.
    Am J Trop Med Hyg, 2020 12;103(6):2233-2238.
    PMID: 32996457 DOI: 10.4269/ajtmh.20-0348
    Independent evaluations of XEh Rapid®, an IgG4-based rapid dipstick test, were performed to assess its diagnostic performance to detect amebic liver abscess (ALA) using 405 samples at seven laboratories in four countries. The test showed high diagnostic specificity (97-100%) when tested with samples from healthy individuals (n = 100) and patients with other diseases (n = 151). The diagnostic sensitivity was tested with a total of 154 samples, and the results were variable. It was high in three laboratories (89-94%), and moderate (72%) and low (38%) in two other laboratories. Challenges and issues faced in the evaluation process are discussed. Nevertheless, XEh Rapid is promising to be developed into a point-of-care test in particular for resource-limited settings, and thus merits further confirmation of its diagnostic sensitivity.
    Matched MeSH terms: Amebiasis/parasitology; Liver Abscess, Amebic/parasitology
  19. Fulltext Diagnostic Potential of an IgE-ELISA in Detecting Strongyloidiasis
    Ahmad H, Balachandra D, Arifin N, Nolan TJ, Lok JB, Hayat Khan A, et al.
    Am J Trop Med Hyg, 2020 12;103(6):2288-2293.
    PMID: 32996454 DOI: 10.4269/ajtmh.20-0265
    Strongyloides stercoralis infection is prevalent worldwide and can cause lifelong infection in immunocompetent individuals, and potentially death in immunosuppressed patients. The diagnosis is hindered by the low sensitivity of microscopic examination, thus making serology an important complementary test to improve the detection rate. However, there were reports that some Strongyloides-infected individuals were negative with specific IgG and IgG4 assays, and other helminth infections were positive with commercial Strongyloides IgG-ELISAs. Thus, there is a need to develop better serodiagnostic methods for strongyloidiasis. We investigated the diagnostic potential of IgE-ELISAs using Strongyloides larval lysate. Sera from two groups infected with Strongyloides served as the positive reference, that is, 1) positive by commercial IgG-ELISAs and IgG4 rapid test, and stool samples positive by microscopy and/or PCR (group IA; n = 20); and 2) negative by IgG-ELISAs and IgG4 rapid test, but stool samples were PCR positive (group IB sera; n = 11). Sera from another two groups served as negative reference (controls), that is, 1) infected with other parasites (group II; n = 73) and 2) healthy donors (group III; n = 22). Results showed a 100% diagnostic sensitivity in detecting sera from groups IA and IB. The latter group of individuals probably had early infection because their IgG and IgG4 assays were negative. The optical density values of group IB sera were also significantly lower than those of group IA (P < 0.003). The IgE-ELISA was 100% specific when tested against sera from groups II and III. This study highlights the diagnostic potential of IgE-ELISA using larval lysate to detect strongyloidiasis, especially those with probable early infection.
    Matched MeSH terms: Feces/parasitology
  20. Fulltext Infectious disease antibodies for biomedical applications: A mini review of immune antibody phage library repertoire
    Lai JY, Lim TS
    Int J Biol Macromol, 2020 Nov 15;163:640-648.
    PMID: 32650013 DOI: 10.1016/j.ijbiomac.2020.06.268
    Antibody phage display is regarded as a critical tool for the development of monoclonal antibodies for infectious diseases. The different classes of antibody libraries are classified based on the source of repertoire used to generate the libraries. Immune antibody libraries are generated from disease infected host or immunization against an infectious agent. Antibodies derived from immune libraries are distinct from those derived from naïve libraries as the host's in vivo immune mechanisms shape the antibody repertoire to yield high affinity antibodies. As the immune system is constantly evolving in accordance to the health state of an individual, immune libraries can offer more than just infection-specific antibodies but also antibodies derived from the memory B-cells much like naïve libraries. The combinatorial nature of the gene cloning process would give rise to a combination of natural and un-natural antibody gene pairings in the immune library. These factors have a profound impact on the coverage of immune antibody libraries to target both disease-specific and non-disease specific antigens. This review looks at the diverse nature of antibody responses for immune library generation and discusses the extended potential of a disease-specified immune library in the context of phage display.
    Matched MeSH terms: Communicable Diseases/parasitology
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