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Change in the incidence of intestinal diseases caused by parasitic protozoa in the Mexican population during the period (2015-2019) and its association with environmental and socioeconomic risk factors. Parasitol Res 2023; 122:903-914. [PMID: 36820929 DOI: 10.1007/s00436-023-07798-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 02/13/2023] [Indexed: 02/24/2023]
Abstract
Diarrheal diseases are one of the main health problems worldwide, especially in developing countries with poor health systems, high rates of poverty, and poor nutrition. The main causative agents of diarrheal disease are bacteria, viruses, and parasites; among the latter, the intestinal protozoa Giardia and Entamoeba stand out. In the present work, a observational analysis of the national surveillance data of amebiasis, giardiasis, and other protozoan intestinal infections was carried out. The data issued by the Directorate General of Epidemiology was analyzed to establish its relationship with geography, socioeconomic, and environmental conditions in Mexico during the 2015-2019 period. New cases of amebiasis decreased by 25.03% between 2015 and 2019, while giardiasis and other protozoan intestinal infections remained constant; in all cases, incidence was higher in females than in males, and children under 5 years of age were the most affected. The contribution of environmental conditions (seasonality, temperature, and humidity) and socioeconomic factors in the number of protozoan intestinal infection cases was assessed by a multivariable regression model using a backward selection procedure. Peaks in cases were observed in spring and summer, which are characterized by warm and humid climates. Additionally, states with high humidity and annual average temperature contribute to a notably higher incidence of these parasites, especially annual average temperature, as demonstrated through multivariable linear regression models. Moreover, the majority of these states have the largest population living in poverty with inadequate measures for the distribution, dispensing, and sanitation of water. These data are essential to incidence rate monitoring and focus efforts on eliminating risk factors and improving health programs in Mexico.
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Rahal A, Sharma DK, Kumar A, Sharma N, Dayal D. In silico to In vivo development of a polyherbal against Haemonchus contortus. Heliyon 2022; 8:e08789. [PMID: 35106389 PMCID: PMC8789534 DOI: 10.1016/j.heliyon.2022.e08789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/09/2021] [Accepted: 01/13/2022] [Indexed: 10/25/2022] Open
Abstract
Haemonchus contortus is a major constraint in the development of small ruminant subsector due to significant production losses incurred by it. The present study explores the antiparasitic potential of three anthelmintic plants (Butea monosperma, Vitex negundo and Catharanthus roseus (L.) G.Don) against H. contortus taking albendazole as the standard. In silico molecular docking and pharmacokinetic prediction studies were conducted with known bioactive molecules of these plants (palasonin, vinblastine, vincristine, betulinic acid and ursolic acid) against Glutamate Dehydrogenase (GDH) and tubulin molecules of the parasite. Methanolic extracts of these herbs were fractionated (hexane, ethyl acetate, chloroform and methanol) and used in in vitro larvicidal studies. Based on the in vitro data, two herbal prototypes were developed and clinically tested. All the 5 ligand molecules showed better binding affnity for GDH and tubulin protein as compared with albendazole and shared similar binding site in the core of the GDH hexamer with slight variations. Albendazole approximately stacked against GLY190A residue, showing hydrophobic interactions with PRO157A and a Pi-cation electrostatic interaction with ARG390 along with four hydrogen bonds. Vincristine formed 2 pi-anionic electrostatic bonds with ASP158 of B and C subunits alongwith hydrogen bonding and hydrophobic interaction and an additional pi-anion electrostatic interaction at ASP158A for vinblastine. Albendazole bound to α-tubulin next to colchicine site whereas vinblastine is bound at the nearby laulimalide/peloruside site of the dimer. Betulinic acid showed lateral interaction between the H2-H3 loop of one alpha subunit and H10 of the adjacent alpha subunit of two tubulin dimers. Ursolic acid and palasonin bound at the intradimer N site of microtubulin involving the H1-H7 and H1-H2 zone, respectively. The in vitro studies demonstrated good dose dependent anthelmintic potential. Both the prototypes were quite efficacious in clearing the infection, keeping it to a minimal for more than 5 months, probably, through direct anthelmintic effect through GDH, tubulin depolymerization and uncoupling as well as indirectly through immunomodulation along with antioxidant and anti-inflammatory properties.
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Affiliation(s)
- Anu Rahal
- Division of Animal Health, ICAR-Central Institute for Research on Goats, Makhdoom, Farah, Mathura, 281122, UP, India
| | - D K Sharma
- Division of Animal Health, ICAR-Central Institute for Research on Goats, Makhdoom, Farah, Mathura, 281122, UP, India
| | - Ashok Kumar
- Division of Animal Health, ICAR-Central Institute for Research on Goats, Makhdoom, Farah, Mathura, 281122, UP, India
| | - Nitika Sharma
- Division of Animal Health, ICAR-Central Institute for Research on Goats, Makhdoom, Farah, Mathura, 281122, UP, India
| | - Deen Dayal
- Division of Animal Health, ICAR-Central Institute for Research on Goats, Makhdoom, Farah, Mathura, 281122, UP, India
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Coffey CM, Collier SA, Gleason ME, Yoder JS, Kirk MD, Richardson AM, Fullerton KE, Benedict KM. Evolving Epidemiology of Reported Giardiasis Cases in the United States, 1995-2016. Clin Infect Dis 2021; 72:764-770. [PMID: 32047932 DOI: 10.1093/cid/ciaa128] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 02/07/2020] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Giardiasis is the most common intestinal parasitic disease of humans identified in the United States (US) and an important waterborne disease. In the United States, giardiasis has been variably reportable since 1992 and was made a nationally notifiable disease in 2002. Our objective was to describe the epidemiology of US giardiasis cases from 1995 through 2016 using National Notifiable Diseases Surveillance System data. METHODS Negative binomial regression models were used to compare incidence rates by age group (0-4, 5-9, 10-19, 20-29, 30-39, 40-49, 50-64, and ≥ 65 years) during 3 time periods (1995-2001, 2002-2010, and 2011-2016). RESULTS During 1995-2016, the average number of reported cases was 19 781 per year (range, 14 623-27 778 cases). The annual incidence of reported giardiasis in the United States decreased across all age groups. This decrease differs by age group and sex and may reflect either changes in surveillance methods (eg, changes to case definitions or reporting practices) or changes in exposure. Incidence rates in males and older age groups did not decrease to the same extent as rates in females and children. CONCLUSIONS Trends suggest that differences in exposures by sex and age group are important to the epidemiology of giardiasis. Further investigation into the risk factors of populations with higher rates of giardiasis will support prevention and control efforts.
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Affiliation(s)
- Cushla M Coffey
- National Centre for Epidemiology and Population Health, Australian National University, Canberra, Australia
| | - Sarah A Collier
- Division of Foodborne, Waterborne and Environmental Diseases, National Center for Emerging Zoonotic and Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Michelle E Gleason
- Division of Foodborne, Waterborne and Environmental Diseases, National Center for Emerging Zoonotic and Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Jonathan S Yoder
- Division of Foodborne, Waterborne and Environmental Diseases, National Center for Emerging Zoonotic and Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Martyn D Kirk
- National Centre for Epidemiology and Population Health, Australian National University, Canberra, Australia
| | - Alice M Richardson
- National Centre for Epidemiology and Population Health, Australian National University, Canberra, Australia
| | - Kathleen E Fullerton
- Division of Foodborne, Waterborne and Environmental Diseases, National Center for Emerging Zoonotic and Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Katharine M Benedict
- Division of Foodborne, Waterborne and Environmental Diseases, National Center for Emerging Zoonotic and Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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Intestinal Giardiasis Disguised as Ulcerative Colitis. Case Rep Gastrointest Med 2018; 2018:8968976. [PMID: 29854495 PMCID: PMC5964594 DOI: 10.1155/2018/8968976] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 04/03/2018] [Indexed: 02/05/2023] Open
Abstract
Parasite-associated colitis is quite rare in clinical practice of Ulcerative Colitis (UC). Here we reported an intestinal giardiasis case that has been diagnosed with UC. Further examination of stool revealed cysts of Giardia. This case completely responded to Albendazole. Giardiasis should be included for the differential diagnosis of UC.
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Gutiérrez-Gutiérrez F, Palomo-Ligas L, Hernández-Hernández JM, Pérez-Rangel A, Aguayo-Ortiz R, Hernández-Campos A, Castillo R, González-Pozos S, Cortés-Zárate R, Ramírez-Herrera MA, Mendoza-Magaña ML, Castillo-Romero A. Curcumin alters the cytoskeleton and microtubule organization on trophozoites of Giardia lamblia. Acta Trop 2017; 172:113-121. [PMID: 28465123 DOI: 10.1016/j.actatropica.2017.04.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 04/06/2017] [Accepted: 04/17/2017] [Indexed: 11/30/2022]
Abstract
Giardia lamblia is a worldwide protozoan responsible for a significant number of intestinal infections. There are several drugs for the treatment of giardiasis, but they often cause side effects. Curcumin, a component of turmeric, has antigiardial activity; however, the molecular target and mechanism of antiproliferative activity are not clear. The effects of curcumin on cellular microtubules have been widely investigated. Since tubulin is the most abundant protein in the cytoskeleton of Giardia, to elucidate whether curcumin has activity against the microtubules of this parasite, we treated trophozoites with curcumin and the cells were analyzed by scanning electron microscopy and confocal microscopy. Curcumin inhibited Giardia proliferation and adhesion in a time-concentration-dependent mode. The higher inhibitory concentrations of curcumin (3 and 15μM) disrupted the cytoskeletal structures of trophozoites; the damage was evident on the ventral disk, flagella and in the caudal region, also the membrane was affected. The immunofluorescence images showed altered distribution of tubulin staining on ventral disk and flagella. Additionally, we found that curcumin caused a clear reduction of tubulin expression. By docking analysis and molecular dynamics we showed that curcumin has a high probability to bind at the interface of the tubulin dimer close to the vinblastine binding site. All the data presented indicate that curcumin may inhibit Giardia proliferation by perturbing microtubules.
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Affiliation(s)
- Filiberto Gutiérrez-Gutiérrez
- Departamento de Fisiología, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico
| | - Lissethe Palomo-Ligas
- Departamento de Fisiología, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico
| | - José Manuel Hernández-Hernández
- Departamento de Biología Celular, Centro De Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, Mexico
| | - Armando Pérez-Rangel
- Departamento de Biología Celular, Centro De Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, Mexico
| | - Rodrigo Aguayo-Ortiz
- Facultad de Química, Departamento de Farmacia, Universidad Nacional Autónoma de México, México City, Mexico
| | - Alicia Hernández-Campos
- Facultad de Química, Departamento de Farmacia, Universidad Nacional Autónoma de México, México City, Mexico
| | - Rafael Castillo
- Facultad de Química, Departamento de Farmacia, Universidad Nacional Autónoma de México, México City, Mexico
| | - Sirenia González-Pozos
- Unidad de microscopia electrónica, Centro De Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México City, Mexico
| | - Rafael Cortés-Zárate
- Departamento de Fisiología, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico
| | - Mario Alberto Ramírez-Herrera
- Departamento de Fisiología, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico
| | - María Luisa Mendoza-Magaña
- Departamento de Fisiología, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico
| | - Araceli Castillo-Romero
- Departamento de Fisiología, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico.
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Gutiérrez-Gutiérrez F, Puebla-Pérez AM, González-Pozos S, Hernández-Hernández JM, Pérez-Rangel A, Alvarez LP, Tapia-Pastrana G, Castillo-Romero A. Antigiardial Activity of Podophyllotoxin-Type Lignans from Bursera fagaroides var. fagaroides. Molecules 2017; 22:E799. [PMID: 28505094 PMCID: PMC6154107 DOI: 10.3390/molecules22050799] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 05/08/2017] [Accepted: 05/09/2017] [Indexed: 01/08/2023] Open
Abstract
Giardiasis, a diarrheal disease, is highly prevalent in developing countries. Several drugs are available for the treatment of this parasitosis; unfortunately, all of them have variable efficacies and adverse effects. Bursera fagaroides has been known for its anti-inflammatory and antidiarrheal properties in Mexican traditional medicine. We investigated the in vitro anti-giardial activities of four podophyllotoxin-type lignans from Bursera fagaroides var. fagaroides, namely, 5'-desmethoxy-β-peltatin-A-methylether (5-DES), acetylpodophyllotoxin (APOD), burseranin (BUR), and podophyllotoxin (POD). All lignans affected the Giardia adhesion and electron microscopy images revealed morphological alterations in the caudal region, ventral disk, membrane, and flagella, to different extents. Only 5-DES, APOD, and POD caused growth inhibition. Using the Caco-2 human cell line as a model of the intestinal epithelium, we demonstrated that APOD displayed direct antigiardial killing activity and low toxicity on Caco-2 cells. This finding makes it an attractive potential starting point for new antigiardial drugs.
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Affiliation(s)
| | - Ana María Puebla-Pérez
- Departamento de Química y Farmacobiología, Universidad de Guadalajara, Guadalajara 44430, Jalisco, Mexico.
| | - Sirenia González-Pozos
- Unidad de Microscopía Electrónica LaNSE, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México 07360, Mexico.
| | - José Manuel Hernández-Hernández
- Departamento de Biología Celular, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México 07360, Mexico.
| | - Armando Pérez-Rangel
- Departamento de Biología Celular, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México 07360, Mexico.
| | - Laura Patricia Alvarez
- Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Morelos 62209, Mexico.
| | - Gabriela Tapia-Pastrana
- Laboratorio de Investigación Biomédica, Hospital Regional de Alta Especialidad de Oaxaca, Oaxaca 71256, Mexico.
| | - Araceli Castillo-Romero
- Departamento de Microbiología y Patología, Universidad de Guadalajara, Guadalajara 44340, Jalisco, Mexico.
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Escobedo AA, Almirall P, Cimerman S, Rodríguez-Morales AJ. Sequelae of giardiasis: an emerging public health concern. Int J Infect Dis 2016; 49:202-3. [DOI: 10.1016/j.ijid.2016.06.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 09/03/2015] [Accepted: 06/07/2016] [Indexed: 11/26/2022] Open
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Long-Term Consequences of Cryptosporidium and Giardia Gastroenteritis. CURRENT TROPICAL MEDICINE REPORTS 2016. [DOI: 10.1007/s40475-016-0078-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Escobedo AA, Almirall P, Ávila I, Salazar Y, Alfonso M. Care-seeking behaviour and diagnostic processes for symptomatic giardiasis in children attending an academic paediatric hospital. Pathog Glob Health 2014; 108:271-8. [PMID: 25253040 PMCID: PMC4216749 DOI: 10.1179/2047773214y.0000000152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Giardiasis is one of the commonest intestinal parasitic infections in Cuba. In order to determine care-seeking behaviour and diagnostic processes in paediatric in-patients with giardiasis, structured questionnaires were administered by interview mothers of children with giardiasis during January to December 2010. During the study period, 97 children were diagnosed with giardiasis, of whom 86 (88·6%) caregivers were interviewed. The median number of days from symptoms onset to the first presentation in a health unit was 2 days (range: 0-15 days). The pattern of care-seeking behaviour was variable; 41 (47·7%) of children initially visited the emergency unit in a paediatric hospital. Sixty-six children had, at least, one further contact for help before diagnosis of giardiasis was made (range: 1-5 contacts) and of the 128 contact visits, 94 (73·4%) were also targeted more to hospitals. There was a median time of 6 days between the first presentation to a health unit until diagnosis, which was mainly made by microscopic examination of duodenal aspiration. Among factors investigated in mothers, only knowing other person with giardiasis had significant association with their ability to suspect giardiasis [odds ratio (OR): 29·8, 95% confidence interval (CI): 3·71-239·4, P = 0·001]. Requesting a faecal specimen or ordering duodenal aspiration for microscopic examination during the first visit appeared associated with correct diagnosis (OR: 3·84, 95% CI: 1·57-9·40, P = 0·003). Efforts should be made to increase doctors' awareness of- and diagnostic skills for childhood giardiasis. At the same time, it is necessary to improve caregivers' awareness about giardiasis.
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Escobedo AA, Almirall P, Rumbaut R, Rodríguez-Morales AJ. Potential impact of macroclimatic variability on the epidemiology of giardiasis in three provinces of Cuba, 2010-2012. J Infect Public Health 2014; 8:80-9. [PMID: 25065512 DOI: 10.1016/j.jiph.2014.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 06/10/2014] [Accepted: 06/13/2014] [Indexed: 10/25/2022] Open
Abstract
Climate change and variability are common phenomena affecting various infectious diseases. Many studies have been performed on vector-borne diseases; however, few studies have addressed such influences on intestinal parasitic diseases (e.g., giardiasis). In this study, using nonlinear Poisson regression models, we assessed the potential associations between macroclimatic variation and giardiasis cases in children and school workers from three provinces of Cuba in the context of large sampling and parasitological assessment. Between 2010 and 2012, 293,019 subjects were assessed, resulting in 6357 positive for Giardia (216.95 cases/10,000 pop.; 95%CI 211.7-222.2). The variation in time for those giardiasis rates ranged from 35.8 to 525.8 cases/10,000 pop. Nonlinear Poisson regression models between the ONI index and the giardiasis incidence indicated a significant association (p<0.01). With lower values of ONI, lower incidence of giardiasis was observed at Havana (pseudo r(2)=0.0576; p<0.001) and Guantánamo (pseudo r(2)=0.0376; p<0.001). Although these results are preliminary and the magnitude of association is not higher, the results were of statistical significance. This result indicates the need to assess in detail in further studies the impact of additional macroclimatic and microclimatic variables on the epidemiology of this still important intestinal parasitic disease, not only in Cuba but also in other countries of the Caribbean and Latin American region.
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Affiliation(s)
- Angel A Escobedo
- Department of Parasitology, Hospital Pediátrico Universitario "Pedro Borrás", La Habana, Cuba; Working Group on Zoonoses, International Society for Chemotherapy, Aberdeen, United Kingdom; Committee on Clinical Parasitology, Panamerican Association for Infectious Diseases (Asociación Panamericana de Infectología), La Habana, Cuba
| | - Pedro Almirall
- Analisys and Health Trends Unit, Unidad Municipal de Higiene, Epidemiología y Microbiología, Plaza, La Habana, Cuba
| | | | - Alfonso J Rodríguez-Morales
- Working Group on Zoonoses, International Society for Chemotherapy, Aberdeen, United Kingdom; Research Group Public Health and Infection, Faculty of Health Sciences, Universidad Tecnológica de Pereira (UTP), Pereira, Risaralda, Colombia; Committee on Zoonoses and Hemorrhagic Fevers of the Colombian Association of Infectious Diseases (Asociación Colombiana de Infectología, ACIN), Bogotá, Colombia.
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Escobedo AA, Almirall P, Alfonso M, Cimerman S, Chacín-Bonilla L. Sexual transmission of giardiasis: a neglected route of spread? Acta Trop 2014; 132:106-11. [PMID: 24434784 DOI: 10.1016/j.actatropica.2013.12.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Revised: 12/28/2013] [Accepted: 12/30/2013] [Indexed: 12/20/2022]
Abstract
Sexually transmitted infections (STIs) are often discussed in the context of syphilis, gonorrhea, herpes, chlamydiasis and AIDS. However, since the past 30 years of the last century, epidemiology and natural history studies have led to improved understanding of giardiasis as a STI, as a result of oral-anal sexual contact. Studies suggest that Giardia is an increasingly recognized infection that may be underdiagnosed under the STI context. Health care providers should maintain a high index of suspicion for Giardia, obtain suitable diagnostic tests to identify and screen those at high risk for this infection, institute appropriate therapy, counsel patients regarding treatment compliance, follow-up, encourage partner notification and teach strategies for preventing the transmission of this disease, including the discussion of the risk of enteric infections after oral-anal sexual contact. We summarize some data concerning the research and clinical literature on Giardia infection as a STI and identify the specific recommendations for control of giardiasis as STI that available evidence indicates can reduce its transmission.
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Guo J, Zheng W, Wang Y, Li Y, Lu S, Feng X. Coexistence of sense and anti-sense mRNAs of variant surface protein in Giardia lamblia trophozoites. Biochem Biophys Res Commun 2014; 444:439-44. [PMID: 24472547 DOI: 10.1016/j.bbrc.2014.01.074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2014] [Accepted: 01/20/2014] [Indexed: 12/26/2022]
Abstract
A strategy of the parasitic protozoan Giardia lamblia to evade attack from the host immune system is periodic changes of its surface antigen, a member of the variant surface protein (VSP) family. A post-transcriptional gene silencing mechanism has been proposed to explain the presence of only one among many possible VSPs at any time. To investigate this phenomenon further, we extracted total RNA from cultured trophozoites of the G. lamblia C2 isolate, and cDNA was reverse-transcribed from the RNA. Sense and anti-sense VSPs were amplified from the total cDNA using nested PCR with primers designed from the 3'-conserved region and the known 5' or 3' end of the cDNA library. Sequence analyses of the amplified products revealed more than 34 full-length antisense VSPs and a smear of sense VSPs. Sequence alignments and comparisons revealed that these VSPs contained variable N-termini and conserved C-termini, and could be classified into 5 clades based on the sizes and variations of the N-terminal sequence. All antisense VSPs existed in the sense forms, but no corresponding antisense VSP existed for sense RNA (snsRNA) 16. The coexistence of sense and antisense VSP mRNAs in cultured G. lamblia supports the post-transcriptional regulation of VSP expression. We propose that VSPs transcribed simultaneously in the sense and antisense forms form double-stranded RNAs (dsRNAs) which are degraded by the Dicer endonuclease, while a VSP without an antisense transcription (e.g., snsRNA16) will be expressed on the surface of Giardia. In addition, in the course of this investigation VSPs were identified that were previously not known. PCR-based amplification of specific sense and antisense VSP cDNAs can be used to identify the specific VSP on G. lamblia trophozoites, which is easier than using specific monoclonal antibody approaches.
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Affiliation(s)
- Junli Guo
- School of Laboratory Medicine, Jilin Medical College, Jilin, Jilin 132013, China; Hainan Provincial Key Laboratory of Tropical Medicine, Hainan Medical College, Haikou 571199, China
| | - Wenyu Zheng
- Department of Hand Microsurgery, Central Hospital of Jilin City, Jilin, Jilin 132000, China
| | - Yuehua Wang
- School of Laboratory Medicine, Jilin Medical College, Jilin, Jilin 132013, China
| | - Yao Li
- School of Laboratory Medicine, Jilin Medical College, Jilin, Jilin 132013, China
| | - Siqi Lu
- Department of Parasitology, Capital Medical University, Beijing 100069, China
| | - Xianmin Feng
- School of Laboratory Medicine, Jilin Medical College, Jilin, Jilin 132013, China.
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