MyMedR

Displaying publications 41 - 60 of 234 in total

Abstract:

Sort:

Homologs of the Brugia malayi diagnostic antigen BmR1 are present in other filarial parasites but induce different humoral immune responses

Noordin R, Aziz RA, Ravindran B

Filaria journal, 2004 Dec 31;3(1):10.
PMID: 15627400

BACKGROUND: The recombinant antigen BmR1 has been extensively employed in both ELISA and immunochromatographic rapid dipstick (Brugia Rapid) formats for the specific and sensitive detection of IgG4 antibodies against the lymphatic filarial parasites Brugia malayi and Brugia timori. In sera of individuals infected with Wuchereria bancrofti the IgG4 reactivity to BmR1 is variable, and cross-reactivity of sera from individuals infected with Onchocerca volvulus or Loa loa was observed only in single cases. In order to characterize the homologs of the BmR1 antigen in W. bancrofti (Wb-BmR1), O. volvulus (Ov-BmR1) and L. loa (Ll-BmR1) the cDNA sequences were identified, the protein expressed and the antibody reactivity of patients' sera was studied. METHODS: PCR methodology was used to identify the cDNA sequences from cDNA libraries and/or genomic DNA of W. bancrofti, O. volvulus and L. loa. The clones obtained were sequenced and compared to the cDNA sequence of BmR1. Ov-BmR1 and Ll-BmR1 were expressed in E. coli and tested using an IgG4-ELISA with 262 serum samples from individuals with or without B. malayi, W. bancrofti, O. volvulus and L. loa infections or various other parasitic infections. BmR1, Ov-BmR1 and Ll-BmR1 were also tested for reactivity with the other three IgG subclasses in patients' sera. RESULTS: Wb-BmR1 was found to be identical to BmR1. Ov-BmR1 and Ll-BmR1 were found to be identical to each other and share 99.7% homology with BmR1. The pattern of IgG4 recognition of all serum samples to BmR1, Ov-BmR1 and Ll-BmR1 were identical. This included weak IgG4 reactivities demonstrated by L. loa- and O. volvulus-infected patients tested with Ov-BmR1 and Ll-BmR1 (or BmR1). With respect to reactivity to other IgG subclasses, sera from O. volvulus- and L. loa-infected patients showed positive reactions (when tested with BmR1, Ov-BmR1 or Ll-BmR1 antigens) only with IgG1. No reactivity was observed with IgG2 or with IgG3. Similarly, ELISAs to detect reactivity to other anti-filarial IgG subclasses antibodies showed that sera from individuals infected with B. malayi or W. bancrofti (active infections as well as patients with chronic disease) were positive with BmR1 only for IgG1 and were negative when tested with IgG2 and with IgG3 subclasses. CONCLUSIONS: This study demonstrates that homologs of the BmR1 antigen are present in W. bancrofti, O. volvulus and L. loa and that these antigens are highly conserved. Recognition of this antigen by patients' sera is similar with regard to IgG1, IgG2 and IgG3, but different for IgG4 antibodies. We conclude that the BmR1 antigen is suitable for detection of IgG4 antibodies in brugian filariasis. However, its homologs are not suitable for IgG4-based diagnosis of other filarial infections.

Matched MeSH terms: Parasites
Fulltext Description of myxosporeans (Cnidaria: Myxozoa) infecting the popular food fish Notopterus notopterus (Pisces: Notopteridae) in Malaysia and India

Borkhanuddin MH, Goswami U, Cech G, Molnár K, Atkinson SD, Székely C

Food Waterborne Parasitol, 2020 Sep;20:e00092.
PMID: 32995584 DOI: 10.1016/j.fawpar.2020.e00092

This study was a co-operative investigation of myxosporean infections of Notopterus notopterus, the bronze featherback, which is a popular food fish in the South Asian region. We examined fish from Lake Kenyir, Malaysia and the River Ganga, Hastinapur, Uttar Pradesh, India, and observed infections with two myxosporeans: Myxidium cf. notopterum (Myxidiidae) and Henneguya ganapatiae (Myxobolidae), respectively. These species were identified by myxospore morphology, morphometry and host tissue affinity, and the original descriptions supplemented with small-subunit ribosomal DNA sequences and phylogenetic analysis. Free myxospores of M. cf. notopterum were found in the gallbladder, and measured 14.7 ± 0.6 μm long and 6.3 ± 0.6 μm wide; host, tissue and myxospore dimensions overlapped with the type, but differed in morphological details (spore shape, valve cell ridges) and locality (Malaysia versus India). Plasmodia and spores of H. ganapatiae were observed in gills, and myxospores had a spore body 9.7 ± 0.4 μm long, 4.5 ± 0.5 μm wide; sample locality, host, tissue, spore morphology and morphometry matched the original description. Small-subunit ribosomal DNA sequences were deposited in GenBank (M. cf. notopterum MT365527, H. ganapatiae MT365528) and both differed by >7% from congeneric species. Although the pathogenicity and clinical manifestation of myxozoan in humans are poorly understood, consumption of raw fish meat with myxozoan infection was reported to be associated with diarrhea. Identification of current parasite fauna from N. notopterus is an essential first step in assessing pathogen risks to stocks of this important food fish.

Matched MeSH terms: Parasites
Fulltext Diagnostic accuracy and limit of detection of ten malaria parasite lactate dehydrogenase-based rapid tests for Plasmodium knowlesi and P. falciparum

Tan AF, Sakam SSB, Rajahram GS, William T, Abd Rachman Isnadi MF, Daim S, et al.

Front Cell Infect Microbiol, 2022;12:1023219.
PMID: 36325471 DOI: 10.3389/fcimb.2022.1023219

BACKGROUND: Plasmodium knowlesi causes zoonotic malaria across Southeast Asia. First-line diagnostic microscopy cannot reliably differentiate P. knowlesi from other human malaria species. Rapid diagnostic tests (RDTs) designed for P. falciparum and P. vivax are used routinely in P. knowlesi co-endemic areas despite potential cross-reactivity for species-specific antibody targets.
METHODS: Ten RDTs were evaluated: nine to detect clinical P. knowlesi infections from Malaysia, and nine assessing limit of detection (LoD) for P. knowlesi (PkA1-H.1) and P. falciparum (Pf3D7) cultures. Targets included Plasmodium-genus parasite lactate dehydrogenase (pan-pLDH) and P. vivax (Pv)-pLDH.
RESULTS: Samples were collected prior to antimalarial treatment from 127 patients with microscopy-positive PCR-confirmed P. knowlesi mono-infections. Median parasitaemia was 788/µL (IQR 247-5,565/µL). Pan-pLDH sensitivities ranged from 50.6% (95% CI 39.6-61.5) (SD BIOLINE) to 87.0% (95% CI 75.1-94.6) (First Response® and CareStart™ PAN) compared to reference PCR. Pv-pLDH RDTs detected P. knowlesi with up to 92.0% (95% CI 84.3-96.7%) sensitivity (Biocredit™). For parasite counts ≥200/µL, pan-pLDH (Standard Q) and Pv-pLDH RDTs exceeded 95% sensitivity. Specificity of RDTs against 26 PCR-confirmed negative controls was 100%. Sensitivity of six highest performing RDTs were not significantly different when comparing samples taken before and after (median 3 hours) antimalarial treatment. Parasite ring stages were present in 30% of pre-treatment samples, with ring stage proportions (mean 1.9%) demonstrating inverse correlation with test positivity of Biocredit™ and two CareStart™ RDTs.For cultured P. knowlesi, CareStart™ PAN demonstrated the lowest LoD at 25 parasites/µL; LoDs of other pan-pLDH ranged from 98 to >2000 parasites/µL. Pv-pLDH LoD for P. knowlesi was 49 parasites/µL. No false-positive results were observed in either P. falciparum-pLDH or histidine-rich-protein-2 channels.
CONCLUSION: Selected RDTs demonstrate sufficient performance for detection of major human malaria species including P. knowlesi in co-endemic areas where microscopy is not available, particularly for higher parasite counts, although cannot reliably differentiate among non-falciparum malaria.

Matched MeSH terms: Parasites*
Fulltext Induction of Protective Immunity against Toxoplasmosis in BALB/c Mice Vaccinated with Toxoplasma gondii Rhoptry-1

Sonaimuthu P, Ching XT, Fong MY, Kalyanasundaram R, Lau YL

Front Microbiol, 2016;7:808.
PMID: 27303390 DOI: 10.3389/fmicb.2016.00808

Toxoplasma gondii is the causative agent for toxoplasmosis. The rhoptry protein 1 (ROP1) is secreted by rhoptry, an apical secretory organelle of the parasite. ROP1 plays an important role in host cell invasion. In this study, the efficacy of ROP1 as a vaccine candidate against toxoplasmosis was evaluated through intramuscular or subcutaneous injection of BALB/c mice followed by immunological characterization (humoral- and cellular-mediated) and lethal challenge against virulent T. gondii RH strain in BALB/c mice. Briefly, a recombinant DNA plasmid (pVAX1-GFP-ROP1) was expressed in CHO cells while expression of recombinant ROP1 protein (rROP1) was carried out in Escherichia coli expression system. Immunization study involved injection of the recombinant pVAX1-ROP1 and purified rROP1 into different group of mice. Empty vector and PBS served as two different types of negative controls. Results obtained demonstrated that ROP1 is an immunogenic antigen that induced humoral immune response whereby detection of a protein band with expected size of 43 kDa was observed against vaccinated mice sera through western blot analysis. ROP1 antigen was shown to elicit cellular-mediated immunity as well whereby stimulated splenocytes with total lysate antigen (TLA) and rROP1 from pVAX1-ROP1 and rROP1-immunized mice, respectively, readily proliferated and secreted large amount of IFN-γ (712 ± 28.1 pg/ml and 1457 ± 31.19 pg/ml, respectively) and relatively low IL-4 level (94 ± 14.5 pg/ml and 186 ± 14.17 pg/ml, respectively). These phenomena suggested that Th1-favored immunity was being induced. Vaccination with ROP1 antigen was able to provide partial protection in the vaccinated mice against lethal challenge with virulent RH strain of tachyzoites. These findings proposed that the ROP1 antigen is a potential candidate for the development of vaccine against toxoplasmosis.

Matched MeSH terms: Parasites
Fulltext Evaluation of Immunoprotection Conferred by the Subunit Vaccines of GRA2 and GRA5 against Acute Toxoplasmosis in BALB/c Mice

Ching XT, Fong MY, Lau YL

Front Microbiol, 2016;7:609.
PMID: 27199938 DOI: 10.3389/fmicb.2016.00609

Toxoplasmosis is a foodborne disease caused by Toxoplasma gondii, an obligate intracellular parasite. Severe symptoms occur in the immunocompromised patients and pregnant women leading to fatality and abortions respectively. Vaccination development is essential to control the disease. The T. gondii dense granule antigen 2 and 5 (GRA2 and GRA5) have been targeted in this study because these proteins are essential to the development of parasitophorous vacuole (PV), a specialized compartment formed within the infected host cell. PV is resistance to host cell endosomes and lysosomes thereby protecting the invaded parasite. Recombinant dense granular proteins, GRA2 (rGRA2) and GRA5 (rGRA5) were cloned, expressed, and purified in Escherichia coli, BL21 (DE3) pLysS. The potential of these purified antigens as subunit vaccine candidates against toxoplasmosis were evaluated through subcutaneous injection of BALB/c mice followed by immunological characterization (humoral- and cellular-mediated) and lethal challenge against virulent T. gondii RH strain in BALB/c mice. Results obtained demonstrated that rGRA2 and rGRA5 elicited humoral and cellular-mediated immunity in the mice. High level of IgG antibody was produced with the isotype IgG2a/IgG1 ratio of ≈0.87 (p < 0.001). Significant increase (p < 0.05) in the level of four cytokines (IFN-γ, IL-2, IL-4, and IL-10) was obtained. The antibody and cytokine results suggest that a mix mode of Th1/Th2-immunity was elicited with predominant Th1-immune response inducing partial protection against T. gondii acute infection in BALB/c mice. Our findings indicated that both GRA2 and GRA5 are potential candidates for vaccine development against T. gondii acute infection.

Matched MeSH terms: Parasites
Fulltext Plasmodium knowlesi and Wuchereria bancrofti: Their Vectors and Challenges for the Future

Vythilingam I

Front Physiol, 2012;3:115.
PMID: 22557977 DOI: 10.3389/fphys.2012.00115

Malaria and filariasis still continue to pose public health problems in developing countries of the tropics. Although plans are in progress for the elimination of both these parasitic vector borne diseases, we are now faced with a daunting challenge as we have a fifth species, Plasmodium knowlesi a simian malaria parasite affecting humans. Similarly in peninsular Malaysia, filariasis was mainly due to Brugia malayi. However, we now see cases of Wuchereria bancrofti in immigrant workers coming into the country. In order to successfully eliminate both these diseases we need to know the vectors involved and introduce appropriate control measures to prevent the diseases occurring in the future. As for knowlesi malaria it is still uncertain if human to human transmission through mosquito bites is occurring. However, P. knowlesi in human is not a rare occurrence anymore and has all the characteristics of a pathogen spreading due to changes in the ecosystem, international travel, and cross border migration. This has created a more complex situation. In order to overcome these challenges we need to revamp our control measures. This paper reviews the vectors of malaria and filariasis in Southeast Asia with special emphasis on P. knowlesi and W. bancrofti in Malaysia and their control strategies.

Matched MeSH terms: Parasites
Fulltext Serum neopterin is elevated in patients infected with Shigella

Singh KK, Wan-Nurfahizul-Izzati W, Ismail A

Gut Pathog, 2010;2(1):9.
PMID: 20727206 DOI: 10.1186/1757-4749-2-9

Neopterin is produced by human macrophages/monocytes when stimulated with interferon-gamma. Production of neopterin is found in serum, cerebrospinal fluid (CSF) and urine of patients with infections by viruses, intracellular bacteria and parasites, autoimmune diseases, malignant tumors and patients in allograft rejection episodes.

Matched MeSH terms: Parasites
Fulltext A cross-sectional study of the prevalence, density, and risk factors associated with malaria transmission in urban communities of Ibadan, Southwestern Nigeria

Awosolu OB, Yahaya ZS, Farah Haziqah MT, Simon-Oke IA, Fakunle C

Heliyon, 2021 Jan;7(1):e05975.
PMID: 33521357 DOI: 10.1016/j.heliyon.2021.e05975

Background: Malaria is a severe global public health challenge that causes significant morbidity and mortality worldwide, particularly in sub-Saharan Africa. This study was designed to determine the prevalence, parasite density, and risk factors associated with malaria infection transmission among residents of two urban communities of Ibadan, southwestern Nigeria.
Materials and methods: A cross-sectional hospital-based study was carried out on 300 participants. Blood samples were obtained. Thick and thin blood films were prepared and viewed using the standard parasitological technique of microscopy. Moreover, data on sociodemographic and environmental variables were obtained using a pre-tested standard questionnaire.
Results: Of the 300 participants examined, a total of 165 (55.0%) were found positive for Plasmodium falciparum with a mean (S.D) parasite density of 1814.70 (1829.117) parasite/μL of blood. The prevalence and parasite density of malaria infection vary significantly (P < 0.05) with age group. Children <5 years old were more likely to have malaria infection and high parasite densities than adults (p < 0.05). Similarly, in relation to gender, males significantly (P < 0.05) had a higher prevalence (60.2%) and mean (S.D) parasite density of malaria infection [2157.73 (1659.570) parasite/μL of blood] compared to females. Additionally, those without formal education had the highest prevalence (73.0%) and mean (S.D) parasite density of infection [2626.96 (2442.195) parasite/μL of blood]. The bivariate logistic regression analysis shows that age group 6-10 (Crude Odds Ratio, COR 0.066, 95% CI: 0.007-0.635), presence of streams/rivers (COR 0.225, 95% CI: 0.103-0.492), distance from streams/rivers within ≤1 km (COR 0.283, 95% CI: 0.122-0.654) and travel to rural area (COR 4.689, 95% CI: 2.430-9.049) were the significant risk factors.
Conclusions: Malaria infection is prevalent in the study area and was greatly influenced by traveling activities from the rural areas to urban centers and vice versa. Multifaceted and integrated control strategy should be adopted. Health education on mosquito prevention and chemoprophylaxis before and during travel to rural areas are essential.

Matched MeSH terms: Parasites
Fulltext The Neglected Cestode Infection: Epidemiology of Hymenolepis Nana Infection Among Children in Rural Yemen

Al-Mekhlafi HM

Helminthologia, 2020 Dec;57(4):293-305.
PMID: 33364898 DOI: 10.2478/helm-2020-0038

Hymenolepis nana is the most common cestode reported in humans worldwide. It is prevalent among children in the tropics and subtropics, particularly in rural poor communities where sanitation is inadequate or lacking. This cross-sectional study aims to determine the prevalence and significant risk factors of H. nana infection among children in rural Yemen. Faecal samples were collected from 498 children and screened for intestinal parasites by using wet mount, formalin-ether concentration and Kato-Katz techniques. A pretested questionnaire was used to collect demographic, socioeconomic, housing condition, and personal hygiene information. Overall, 77.5 % (386/498) of the children were found to be infected by at least one intestinal parasite species. The overall prevalence of H. nana was 17.5 % (87/498). Multivariate analysis confirmed that an age of < 6 years (adjusted odds ratio [AOR] = 4.28; 95 % (confidence interval [CI] = 2.04, 8.98), presence of other family members infected with H. nana (AOR = 2.48; 95 % CI = 1.45, 4.24), living in the highlands (AOR = 2.87; 95 % CI = 1.56, 5.26), living in a house without improved toilet facilities (AOR = 2.19; 95 % CI = 1.23, 3.88), not washing vegetables before consumption (AOR = 2.11; 95 % CI = 1.06, 4.19), and not washing hands after defecation (AOR = 1.88; 95 % CI = 1.08, 3.27) were the key factors significantly associated with H. nana infection among the studied children. In conclusion, H. nana is prevalent among children in rural Yemen, particularly among preschool-aged children. Thus, an integrated and effective programme to control intestinal parasitic infections should include preschool-aged children. Such a programme should focus on providing health education on hygienic practices, providing adequate sanitation and improved sources of drinking water, and screening and treating other infected family members.

Matched MeSH terms: Parasites
Intestinal parasites in hemodialysis patients from developing countries: A systematic review and meta-analysis

Taghipour A, Olfatifar M, Rostami A, Foroutan M, Vasigala V, Norouzi M

Hemodial Int, 2020 01;24(1):12-21.
PMID: 31804770 DOI: 10.1111/hdi.12796

Intestinal parasitic infection (IPI) is the main cause of gastrointestinal complications in hemodialysis patients due to their impaired immune systems. We conducted a systematic review and meta-analysis to evaluate the prevalence and odds ratio (OR) of IPIs in this population. Relevant eligible studies were identified by searching the PubMed, Science Direct, Scopus, Web of Science, and Google scholar databases up to January 30, 2019. A random-effects meta-analysis model was used to estimate the pooled prevalence, OR, and 95% confidence intervals (CI). Twenty-two studies, from Turkey, Iran, Brazil, Egypt, Saudi Arabia, Pakistan, and Malaysia met eligibility criteria for analysis, and included 11 using a case-control design (980 patients and 893 controls) and 11 studies using a cross-sectional design (a total of 1455 participants). Cross-sectional studies suggested that the pooled prevalence of IPIs in hemodialysis patients was 24% (95% CI, 14-36%; 307/1455). In studies using a case-control design, the pooled prevalence of IPIs in hemodialysis patients (30%, 330/980) was found to be significantly higher than controls (10%, 115/893) (OR, 3.40; 95%CI, 2.37-4.87). With respect to the parasites, Cryptosporidium spp. (OR, 4.49; 95%CI, 2.64-7.64) and Blastocystis sp. (OR, 4.03; 95%CI, 1.20-13.51) were significantly higher in hemodialysis patients compared to the controls. The current study revealed a high prevalence of IPIs in hemodialysis patients from countries in which the baseline prevalence of parasitic infection is high. We recommend that periodic screenings for IPIs in such countries should be incorporated into the routine clinical care of hemodialysis patients.

Matched MeSH terms: Parasites
Cutaneous larva migrans in a beach volleyball player

Krzywanski J, Kuchar E, Mierzynski R

IDCases, 2021;24:e01084.
PMID: 33889485 DOI: 10.1016/j.idcr.2021.e01084

Athletes playing beach volleyball come into contact with sand and may contract skin parasites. We present a case of cutaneous larva migrans in a 20-year-old Polish female beach volleyball player. The athlete participated in The World Tour in Asia (China, Malaysia, Cambodia) a month before. In the beginning, her skin lesions were misdiagnosed as allergic reactions and treated with antihistamines. The disease in the form of a pruritic, migratory serpiginous skin eruption on legs was diagnosed during routine medical examination at the National Centre for Sports Medicine in Warsaw. She was treated successfully with albendazole and cetirizine. The skin lesions resolved entirely within two weeks.

Matched MeSH terms: Parasites
Plasmodium knowlesi - an emerging pathogen

Ahmed MA, Cox-Singh J

ISBT science series, 2015 Apr;10(Suppl 1):134-140.
PMID: 26029250

Ten years have passed since the publication of a large focus of Plasmodium knowlesi infections in the human population. The discovery was made during a molecular investigation of atypical P. malariae cases in the Kapit Health Division, Sarawak, Malaysian Borneo. Patients were more symptomatic with higher parasite counts than expected in P. malariae infections. The investigation found only P. knowlesi DNA present in patient blood samples. Morphological similarity had allowed P. knowlesi to masquerade as P. malariae during routine diagnostic microscopy for malaria. P. knowlesi, a malaria parasite of macaque monkeys, had entered the human population. The subsequent development of P. knowlesi species-specific PCR assays soon demonstrated that the entry was not confined to the Kapit Division but extended across island and mainland Southeast Asia. Relevant clinical descriptions and guidelines for the treatment and management of patents with P. knowlesi malaria were not available. Nor was it clear whether P. knowlesi had undergone a host switch event into the human population or if infections were zoonotic. The outputs of studies on P. knowlesi malaria during the past 10 years will be summarized, highlighting major findings within the context of pathophysiology, virulence, host switch events, treatment, control and importantly malaria elimination.

Matched MeSH terms: Parasites
Fulltext Plasmodium knowlesi malaria: current research perspectives

Amir A, Cheong FW, de Silva JR, Liew JWK, Lau YL

Infect Drug Resist, 2018;11:1145-1155.
PMID: 30127631 DOI: 10.2147/IDR.S148664

Originally known to cause simian malaria, Plasmodium knowlesi is now known as the fifth human malaria species. Since the publishing of a report that largely focused on human knowlesi cases in Sarawak in 2004, many more human cases have been reported in nearly all of the countries in Southeast Asia and in travelers returning from these countries. The zoonotic nature of this infection hinders malaria elimination efforts. In order to grasp the current perspective of knowlesi malaria, this literature review explores the different aspects of the disease including risk factors, diagnosis, treatment, and molecular and functional studies. Current studies do not provide sufficient data for an effective control program. Therefore, future direction for knowlesi research is highlighted here with a final aim of controlling, if not eliminating, the parasite.

Matched MeSH terms: Parasites
Genetic diversity of zoonotic malaria parasites from mosquito vector and vertebrate hosts

Wong ML, Ahmed MA, Sulaiman WYW, Manin BO, Leong CS, Quan FS, et al.

Infect Genet Evol, 2019 09;73:26-32.
PMID: 30999059 DOI: 10.1016/j.meegid.2019.04.010

We explored and constructed haplotype network for simian malaria species: Plasmodium knowlesi, P. cynomolgi and P. inui aiming to understand the transmission dynamics between mosquitoes, humans and macaques. Mosquitoes were collected from villages in an area where zoonotic malaria is prevalent. PCR analysis confirmed Anopheles balabacensis as the main vector for macaque parasites, moreover nearly 60% of the mosquitoes harboured more than one Plasmodium species. Fragments of the A-type small subunit ribosomal RNA (SS rRNA) amplified from salivary gland sporozoites, and equivalent sequences obtained from GenBank were used to construct haplotype networks. The patterns were consistent with the presence of geographically distinct populations for P. inui and P. cynomolgi, and with three discrete P. knowlesi populations. This study provides a preliminary snapshot of the structure of these populations, that was insufficient to answer our aim. Thus, collection of parasites from their various hosts and over time, associated with a systematic analysis of a set of genetical loci is strongly advocated in order to obtain a clear picture of the parasite population and the flow between different hosts. This is important to devise measures that will minimise the risk of transmission to humans, because zoonotic malaria impedes malaria elimination.

Matched MeSH terms: Parasites
Sequence diversity and positive selection at the Duffy-binding protein genes of Plasmodium knowlesi and P. cynomolgi: Analysis of the complete coding sequences of Thai isolates

Putaporntip C, Kuamsab N, Jongwutiwes S

Infect Genet Evol, 2016 Oct;44:367-375.
PMID: 27480919 DOI: 10.1016/j.meegid.2016.07.040

Plasmodium knowlesi and P. cynomolgi are simian malaria parasites capable of causing symptomatic human infections. The interaction between the Duffy binding protein alpha on P. knowlesi merozoite and the Duffy-antigen receptor for chemokine (DARC) on human and macaque erythrocyte membrane is prerequisite for establishment of blood stage infection whereas DARC is not required for erythrocyte invasion by P. cynomolgi. To gain insights into the evolution of the PkDBP gene family comprising PkDBPα, PkDBPβ and PkDBPγ, and a member of the DBP gene family of P. cynomolgi (PcyDBP1), the complete coding sequences of these genes were analyzed from Thai field isolates and compared with the publicly available DBP sequences of P. vivax (PvDBP). The complete coding sequences of PkDBPα (n=11), PkDBPβ (n=11), PkDBPγ (n=10) and PcyDBP1 (n=11) were obtained from direct sequencing of the PCR products. Nucleotide diversity of DBP is highly variable across malaria species. PcyDBP1 displayed the greatest level of nucleotide diversity while all PkDBP gene members exhibited comparable levels of diversity. Positive selection occurred in domains I, II and IV of PvDBP and in domain V of PcyDBP1. Although deviation from neutrality was not detected in domain II of PkDBPα, a signature of positive selection was identified in the putative DARC binding site in this domain. The DBP gene families seem to have arisen following the model of concerted evolution because paralogs rather than orthologs are clustered in the phylogenetic tree. The presence of identical or closely related repeats exclusive for the PkDBP gene family suggests that duplication of gene members postdated their divergence from the ancestral PcyDBP and PvDBP lineages. Intragenic recombination was detected in all DBP genes of these malaria species. Despite the limited number of isolates, P. knowlesi from Thailand shared phylogenetically related domain II sequences of both PkDBPα and PkDBPγ with those from Peninsular Malaysia, consistent with their geographic proximity.

Matched MeSH terms: Parasites
Fulltext An overview of foodborne illness and food safety in Malaysia

Abdul-Mutalib, N.A., Syafinaz, A.N., Sakai, K., Shirai, Y.

International Food Research Journal, 2015;22(3):896-901.
MyJurnal

Foodborne disease has been associated with microorganisms like bacteria, fungi, viruses and parasites. Most commonly, the outbreaks take place due to the ingestion of pathogenic bacteria like Salmonella Typhi, Escherichia coli, Staphylococcus aureus, Vibrio cholera, Campylobacter jejuni, and Listeria monocytogenes. The disease usually happens as a result of toxin secretion of the microorganisms in the intestinal tract of the infected person. Usually, the level of hygiene in the food premises reflect the quality of the food item, hence restaurant or stall with poor sanitary condition is said to be the contributor to food poisoning outbreak. In Malaysia, food poisoning cases are not rare because the hot and humid climate of this country is very suitable for the growth of the foodborne bacteria. The government is also implementing strict rules to ensure workers and owners of food premises prioritize the cleanliness of their working area. Training programme for food handlers can also help them to implement hygiene as a routine in a daily basis. A lot of studies have been done to reduce foodborne diseases. The results can give information about the types of microorganisms, and other components that affect their growth. The result is crucial to determine how the spread of foodborne bacteria can be controlled safely and the outbreak can be reduced.

Matched MeSH terms: Parasites
Fulltext Pathology of lymphatic filariasis

Mak JW

International e-Journal of Science, Medicine & Education, 2012;6 Suppl:S80-86.
MyJurnal

Developing and adult worms of the human lymphatic filarial parasites (Wuchereria bancrofti,
Brugia malayi, and Brugia timori) are located mainly in the lymphatic system and occasionally in aberrant sites like subcutaneous and conjunctival cysts. Lymphatic
pathology ranging from dilatation of lymphatic channels and lymphangiectasia are detected on ultrasonography in apparently healthy, amicrofilaraemic, but filarial antigen positive individuals in endemic areas. Microfilariae are distributed in various organs and may be associated with immune mediated pathology at these sites; tropical pulmonary eosinophilia is characterized by intense immune mediated destruction of microfilariae in the lung parenchyma. In the spleen and other sites, nodular granulomatous lesions can occur where microfilariae are trapped and destroyed. The finding of Wolbachia endosymbionts in all stages of lymphatic filarial parasites has provided new insight on the adverse reactions
associated with anti-filarial chemotherapy. Inflammatory molecules mainly lipopolysaccharide (LPS)-like molecules released from endosymbionts on death of the
parasites are largely responsible for the adverse reactions encountered during anti-filarial chemotherapy. Prenatal tolerance or sensitization to parasite derived molecules can immune-modulate and contribute to both pathology and susceptibility/resistance to infection. Pathological responses thus depend not only on exposure to filarial antigens/infection, but also on host-parasiteendosymbiont factors and to intervention with antifilarial treatment. Treatment induced or host mediated death of parasites are associated with various grades of inflammatory response, in which eosinophils and LPS from endosymbionts play prominent roles, leading to death of the parasite, granulomatous formation, organization and fibrosis. The non-human primate (Presbytis spp.) model of
Brugia malayi developed for the tertiary screening of anti-filarial compounds has provided unique opportunities for the longitudinal study of the pathology associated with lymphatic filariasis. The pathology in this non-human primate model closely follows that seen in
human lymphatic filarial infections and correlates with clinical evidence of lymphatic pathology as detected with ultrasonography. These studies also show that successful treatment as detected by loss of motility and calcification of worms on ultrasonography is associated with reversal of early dilatations of lymphatic channels.

Matched MeSH terms: Parasites
Fulltext Parasite community structure in sympatric Bornean primates

Frias L, Hasegawa H, Chua TH, Sipangkui S, Stark DJ, Salgado-Lynn M, et al.

Int J Parasitol, 2021 10;51(11):925-933.
PMID: 33862059 DOI: 10.1016/j.ijpara.2021.03.003

Parasites are important components of ecosystems, influencing trophic networks, competitive interactions and biodiversity patterns. Nonetheless, we are not nearly close to disentangling their complex roles in natural systems. Southeast Asia falls within global areas targeted as most likely to source parasites with zoonotic potential, where high rates of land conversion and fragmentation have altered the circulation of wildlife species and their parasites, potentially resulting in altered host-parasite systems. Although the overall biodiversity in the region predicts equally high, or even higher, parasite diversity, we know surprisingly little about wild primate parasites, even though this constitutes the first step towards a more comprehensive understanding of parasite transmission processes. Here, we characterise the gastrointestinal helminth parasite assemblages of a community of Bornean primates living along the Kinabatangan floodplain in Sabah (Malaysian Borneo), including two species endemic to the island. Through parasitological analyses, and by using several measures of parasite infection as proxies for parasite diversity and distribution, we show that (i) most parasite taxonomic groups are not limited to a single host, suggesting a greater flexibility for habitat disturbance, (ii) parasite infracommunities of nocturnal primates differ from their diurnal counterparts, reflecting both phylogenetic and ecological constraints, and (iii) soil-transmitted helminths such as whipworm, threadworm and nodule worm are widespread across the primate community. This study also provides new parasite records for southern pig-tailed macaques (Macaca nemestrina), silvered langurs (Trachypithecus cristatus) and Western tarsiers (Cephalopachus bancanus) in the wild, while adding to the limited records for the other primate species in the community. Given the information gap regarding primate-parasite associations in the region, the information presented here should prove relevant for future studies of parasite biodiversity and infectious disease ecology in Asia and elsewhere.

Matched MeSH terms: Host-Parasite Interactions; Parasites*
Fulltext Negative effects of Kudoa islandica n. sp. (Myxosporea: Kudoidae) on aquaculture and wild fisheries in Iceland

Kristmundsson A, Freeman MA

Int J Parasitol Parasites Wildl, 2014 Aug;3(2):135-46.
PMID: 25161912 DOI: 10.1016/j.ijppaw.2014.06.001

In the early 2000s, experimental rearing of spotted wolffish, Anarhichas minor, was started in Iceland. Health surveillance, carried out at regular intervals during the rearing period, revealed persistent and highly prevalent Kudoa infections of fish muscles which caused great financial losses due to post mortem myoliquefaction. In addition, during the traditional process of drying and smoking wild Atlantic lumpfish, Cyclopterus lumpus, the muscles from some fish almost completely disappear and the fish have to be discarded. To describe the etiological agent responsible for these conditions, spotted wolffish, Atlantic wolffish Anarhichas lupus, northern wolffish Anarhichas denticulatus and Atlantic lumpfish were caught off the Icelandic coast and examined for the presence of Kudoa. We describe a novel myxosporean, Kudoa islandica n. sp., using morphological and molecular data, and show with histopathology that it causes extensive myoliquefaction in three different wild fish hosts, which all are commercially valuable species in Iceland. Although some spore dimensions varied significantly between fish species, the molecular analyses showed that the same parasite was responsible for infection in all fish. The northern wolffish was not found to be infected. Although robustly placed in the Kudoa clade in phylogenetic analyses, K. islandica was phylogenetically distinct from other kudoids. A single myxosporean, K. islandica, is responsible for the infections in the somatic muscles of lumpfish and wolffish, causing extensive post mortem myoliquefaction. This myxosporean is likely to infect other fish species and it is important to study its life cycle in order to evaluate any threat to salmonid culture via the use of lumpfish as a biocontrol for sea lice.

Matched MeSH terms: Parasites
Fulltext First molecular investigation of haemosporidian parasites in Thai bat species

Arnuphapprasert A, Riana E, Ngamprasertwong T, Wangthongchaicharoen M, Soisook P, Thanee S, et al.

Int J Parasitol Parasites Wildl, 2020 Dec;13:51-61.
PMID: 32904325 DOI: 10.1016/j.ijppaw.2020.07.010

Malaria parasites in the phylum Apicomplexa (Order: Haemosporida) infect diverse vertebrates and invertebrate hosts. At least seven genera of haemosporidian parasites have been described to exclusively infect bats. Most of these parasites remain enigmatic with a poorly known host range. Here, we investigated 271 bats belonging to 21 species and seven families from six provinces of Thailand. Overall, 124 out of 271 bats (45.8%) were positive for haemosporidian parasites, while none had Plasmodium, based on microscopic examination of blood smears and PCR amplification. We obtained 19 distinct cytochrome b (cytb) nucleotide haplotypes of Hepatocystis from seven bat species (families: Craseonycteridae, Hipposideridae, Pteropodidae, and Rhinolophidae). Nycteria was found in four bat species (Craseonycteridae, Emballonuridae, Megadermatidae, and Pteropodidae) and Polychromophilus in two species (Emballonuridae, Vespertilionidae). Phylogenetic analysis inferred from cytb sequences placed Hepatocystis into 2 different clades. Most Hepatocystis infections were found in insectivorous bats and clustered together with a sequence from Hipposideros larvatus in Cambodia (in subclade 1a). A single sequence of Hepatocystis obtained from a frugivorous bat, Cynopterus brachyotis, was placed in the same clade with Hepatocystis from the same bat species previously reported in Malaysia (clade 2). Nycteria in these Thai bats were clearly separated from the African isolates previously reported in bats in the family Rhinolophidae. Polychromophilus murinus from Myotis siligorensis was placed in a distinct clade (clade 2) from Polychromophilus melanipherus isolated from Taphozous melanopogon (clade 1). These results confirmed that at least two distinct species of Polychromophilus are found in Thailand. Collectively, Hepatocystis presented no host specificity. Although Megaderma spasma seemed to be infected by only Nycteria, its respective parasite does not show specificity to only a single bat host. Polychromophilus murinus and P. melanipherus seem to infect a narrower host range or are somehow restricted to bats in the families Vespertilionidae and Emballonuridae, respectively.

Matched MeSH terms: Parasites

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links