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Daniel E. Snyder - One of the best experts on this subject based on the ideXlab platform.
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Epidemiology of Ostertagia Ostertagi in cow-calf herds in the southeastern USA.
Veterinary parasitology, 1993Co-Authors: Daniel E. SnyderAbstract:Abstract Ostertagia Ostertagi is commonly found in the brood cow and nursing calf in the southeastern USA, this information being derived from fecal egg counts, coproculture and necropsy results; however, clinical disease and large burdens of this parasite are rarely reported. Fecal egg counts in brood cows are routinely low and are generally reported to be 10 eggs per gram of feces (EPG) or less. Nematode egg counts in spring-born calves are also generally low prior to weaning; they increase steadily during the spring and summer and peak from late summer to fall weaning. That egg counts in spring-born calves are low for several months after birth is probably a reflection of minimal grazing activity. It appears that Ostertagia Ostertagi may be of equal or less importance than other nematode genera for spring-born calves in the southeastern USA. The role that Ostertagia Ostertagi plays in fall-born calves or in year-round calving herds has not been adquately investigated. Also, the role that the adult cow plays, with low egg counts and small Ostertagia Ostertagi burdens, in contamination of pasture is not understood during either lactation or dry periods. Treatment of beef calves prior to, or at weaning can reduce contamination and transmission of gastrointestinal parasites on pastures which may be subsequently grazed by these or other weaned calves. Data on parasite population dynamics from tracer calf studies in cow-calf herds in the southeastern USA have identified peak periods of transmission and incidence of specific genera or stages. This information, in conjunction with routinely used cattle production and management practices such as time of calving, should provide means to more accurately define optimal timing for strategic parasite treatment programs and their overall effect on beef production in the southeastern USA.
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Epidemiology of Ostertagia Ostertagi in cow-calf herds in the southeastern USA.
Veterinary parasitology, 1993Co-Authors: Daniel E. SnyderAbstract:Ostertagia Ostertagi is commonly found in the brood cow and nursing calf in the southeastern USA, this information being derived from fecal egg counts, coproculture and necropsy results; however, clinical disease and large burdens of this parasite are rarely reported. Fecal egg counts in brood cows are routinely low and are generally reported to be 10 eggs per gram of feces (EPG) or less. Nematode egg counts in spring-born calves are also generally low prior to weaning; they increase steadily during the spring and summer and peak from late summer to fall weaning. That egg counts in spring-born calves are low for several months after birth is probably a reflection of minimal grazing activity. It appears that Ostertagia Ostertagi may be of equal or less importance than other nematode genera for spring-born calves in the southeastern USA. The role that Ostertagia Ostertagi plays in fall-born calves or in year-round calving herds has not been adequately investigated. Also, the role that the adult cow plays, with low egg counts and small Ostertagia Ostertagi burdens, in contamination of pasture is not understood during either lactation or dry periods. Treatment of beef calves prior to, or at weaning can reduce contamination and transmission of gastrointestinal parasites on pastures which may be subsequently grazed by these or other weaned calves. Data on parasite population dynamics from tracer calf studies in cow-calf herds in the southeastern USA have identified peak periods of transmission and incidence of specific genera or stages. This information, in conjunction with routinely used cattle production and management practices such as time of calving, should provide means to more accurately define optimal timing for strategic parasite treatment programs and their overall effect on beef production in the southeastern USA.
Jozef Vercruysse - One of the best experts on this subject based on the ideXlab platform.
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Experimental selection for ivermectin resistance in Ostertagia Ostertagi in cattle
Veterinary Parasitology, 2007Co-Authors: A.m. Van Zeveren, Edwin Claerebout, S. Casaert, Roger Alvinerie, P. Geldhof, Jozef VercruysseAbstract:Recent reports of suspected ivermectin (IVM) resistance in Ostertagia Ostertagi have highlighted the need for research into the mechanisms of IVM resistance. However, there are no reports of resistant field isolates of O. Ostertagi, which have been characterized for molecular research. Therefore, an anthelmintic susceptible O. Ostertagi population was selected for IVM resistance by repeatedly exposing the population to subtherapeutic and therapeutic levels of IVM over 10 generations. In each selection round, a group of calves was infected with the progeny of the previous IVM-selected O. Ostertagi population. In the last selection round a therapeutic IVM dose (0.2 mg/kg BW) only reduced the faecal egg counts by 57% and 65% on days 7 and 14 after treatment, respectively. In contrast, the therapeutic IVM dose was 100% effective at eliminating the parental IVM-susceptible isolate.
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A SMALL HEAT SHOCK PROTEIN OF Ostertagia Ostertagi: STAGE-SPECIFIC EXPRESSION, HEAT INDUCIBILITY, AND PROTECTION TRIAL
The Journal of parasitology, 2006Co-Authors: Isabel Vercauteren, Jozef Vercruysse, Veerle De Maere, Mieke Stevens, Kris Gevaert, Edwin ClaereboutAbstract:In this study, we isolated and analyzed a small heat shock protein (HSP) of Ostertagia Ostertagi (Oo-HSP18). Oo-hsp18 is encoded by a single-copy gene and the full-length cDNA represents an 18-kDa protein. The expression of Oo-hsp18 is highly stage specific and restricted to the adult stage. The protein is synthesized in a tissue-specific manner and localized in the body muscle layer. The levels of Oo-hsp18 mRNAs are sharply induced by heat shock but not by other stressors such as levamisole and H2O2. A vaccination trial with recombinant Oo-HSP18 failed to protect calves against a challenge infection.
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Molecular analysis of astacin-like metalloproteases of Ostertagia Ostertagi
Parasitology, 2004Co-Authors: V. De Maere, Jozef Vercruysse, Peter Geldhof, Isabel Vercauteren, Kris Gevaert, Edwin ClaereboutAbstract:In this study, we describe the Molecular analysis of zinc-metalloproteases from the abomasal nematode Ostertagia Ostertagi which were exclusively recognized by local antibodies of immune cattle. Full-length or partial coding sequences of 4 different zinc-metalloprotease cDNAs of Ostertagia (met-1, -2, -3 and -4) were amplified using gene-specific primers using the 3'- and 5'-Rapid Amplification of cDNA Ends (RACE) technique. Sequence analysis identified the cDNAs as encoding zinc-metalloproteases, which showed between 62%, and 70% homology to a metalloprotease 1 precursor of Ancylostoma caninum. The full-length cDNA of met-1 consists of an open reading frame (ORF) of 586 amino acids which contains 5 potential N-glycosylation sites and a predicted zinc-binding domain (HEBXHXBGFXHEXXRXDRD). The complete coding sequence of met-3 contains an ORF of 508 aa and the same conserved zinc-binding domain. These domains are signature sequences of the astacin family of the superfamily of metzincin metalloproteases. The presence of a threonine amino acid after the third histidine in M ET-l and MET-3, however, may place them in a new family or subfamily. Real-time PCR analysis of L3, exsheathed L3, L, and adult cDNA identified transcription of the 4 metal lop roteases in different life-stages. The protein MET-1 was expressed in insect cells using the baculovirus expression system but the immunization of calves with this molecule did not lead to protection against challenge infection.
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proteinases released in vitro by the parasitic stages of the bovine abomasal nematode Ostertagia Ostertagi
Parasitology, 2000Co-Authors: Peter Geldhof, Joost Agneessens, Edwin Claerebout, D Knox, Jozef VercruysseAbstract:Host tissue penetration, feeding and immune evasion by helminth parasites may be mediated by both mechanical processes and histolytic products released by the parasite. The aim of this study was to investigate potential histolytic products released during in vitro maintenance of exsheathed third (L3) and 4th larval stage (L4) and adult Ostertagia Ostertagi. Therefore, the pH optima, substrate specificity, molecular size and inhibitor sensitivity of in vitro released (IVR) proteinases were analysed by spectrophotometry and substrate gel electrophoresis. It was shown that L3, L4 and adult IVR proteinases degrade a variety of protein substrates in a pH-dependent and stage-specific manner. At alkaline pH, gelatin, casein and fibrinogen were degraded by metallo- and serine proteinases. In contrast, mucin, fibrinogen, albumin and haemoglobin were degraded at acidic pH by aspartyl protease- and cathepsin L-like activity. At pH 3, the heavy chain of bovine IgG was completely degraded by an aspartyl proteinase secreted by all 3 parasitic stages. The specificity of the L3, L4 and adult Ostertagia Ostertagi proteinases against the different substrates indicates variable functional requirements.
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Identification of Ostertagia Ostertagi specific cells in bovine abomasal lymph nodes.
Veterinary immunology and immunopathology, 2000Co-Authors: T. De Marez, Jozef Vercruysse, Eric Cox, Bruno GoddeerisAbstract:To investigate the contribution of different bovine cell subpopulations in the development of in vitro induced responses by Ostertagia Ostertagi third larval antigen extract (L3), bovine abomasal lymph node cell suspensions were depleted of specific cell populations. The depleted cell suspensions were subsequently assayed for their proliferative responses to O. Ostertagi L3 antigen extract. Proliferative responses to O. Ostertagi L3 antigen extract were restricted to a CD2+ CD4- CD8- cell population and MHC II+ cells different from B-cells were of major importance. Depletion of CD4, CD8, CD4CD8, IgM or CD21 positive cells did not decrease proliferation to L3 antigen extract. Depletion of gammadelta T-cells, which also comprise a subpopulation of CD2+ CD4- CD8- cells, reduced proliferation to L3 antigen extract only in one animal. The results suggest that either gammadelta T-cells could be involved in the proliferation or that another as yet unidentified population is important for proliferation. The precise role of these populations during infection with O. Ostertagi and the mechanism by which these cells may influence the host immune response are important issues that remain to be elucidated.
Edwin Claerebout - One of the best experts on this subject based on the ideXlab platform.
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Experimental selection for ivermectin resistance in Ostertagia Ostertagi in cattle
Veterinary Parasitology, 2007Co-Authors: A.m. Van Zeveren, Edwin Claerebout, S. Casaert, Roger Alvinerie, P. Geldhof, Jozef VercruysseAbstract:Recent reports of suspected ivermectin (IVM) resistance in Ostertagia Ostertagi have highlighted the need for research into the mechanisms of IVM resistance. However, there are no reports of resistant field isolates of O. Ostertagi, which have been characterized for molecular research. Therefore, an anthelmintic susceptible O. Ostertagi population was selected for IVM resistance by repeatedly exposing the population to subtherapeutic and therapeutic levels of IVM over 10 generations. In each selection round, a group of calves was infected with the progeny of the previous IVM-selected O. Ostertagi population. In the last selection round a therapeutic IVM dose (0.2 mg/kg BW) only reduced the faecal egg counts by 57% and 65% on days 7 and 14 after treatment, respectively. In contrast, the therapeutic IVM dose was 100% effective at eliminating the parental IVM-susceptible isolate.
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A SMALL HEAT SHOCK PROTEIN OF Ostertagia Ostertagi: STAGE-SPECIFIC EXPRESSION, HEAT INDUCIBILITY, AND PROTECTION TRIAL
The Journal of parasitology, 2006Co-Authors: Isabel Vercauteren, Jozef Vercruysse, Veerle De Maere, Mieke Stevens, Kris Gevaert, Edwin ClaereboutAbstract:In this study, we isolated and analyzed a small heat shock protein (HSP) of Ostertagia Ostertagi (Oo-HSP18). Oo-hsp18 is encoded by a single-copy gene and the full-length cDNA represents an 18-kDa protein. The expression of Oo-hsp18 is highly stage specific and restricted to the adult stage. The protein is synthesized in a tissue-specific manner and localized in the body muscle layer. The levels of Oo-hsp18 mRNAs are sharply induced by heat shock but not by other stressors such as levamisole and H2O2. A vaccination trial with recombinant Oo-HSP18 failed to protect calves against a challenge infection.
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Protection studies with a globin-enriched protein fraction of Ostertagia Ostertagi.
Veterinary parasitology, 2005Co-Authors: Edwin Claerebout, P. Geldhof, S Raes, W D Smith, D Pettit, T Geurden, J VercruysseAbstract:The protective capacity of an adult stage Ostertagia Ostertagi globin antigen was tested in four vaccination experiments in cattle. In a preliminary experiment, calves were vaccinated three times intraperitoneally with 250 microg globin in Freund's adjuvant and challenged with a trickled infection of 25,000 infective larvae. In three subsequent field studies, calves were vaccinated twice or three times intramuscularly with 80-100 microg globin in Quil A and challenged with a natural gastrointestinal nematode infection on pasture. Higher globin-specific antibody levels were detected in the vaccinated calves than in the control animals in all vaccine trials. In the preliminary experiment, geometric mean cumulative egg counts in the globin group were reduced by 52% and total worm burdens were reduced by 28%, compared to the controls. In the first field trial cumulative faecal egg counts were reduced by 63% in the vaccinated calves. However, the reduction in faecal egg output in these two experiments was not statistically significant and no reduction in faecal egg counts was observed in the vaccinated animals in the two last field trials. In conclusion, vaccination of calves with O. Ostertagi globin resulted in highly variable protection levels after challenge infection.
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Molecular analysis of astacin-like metalloproteases of Ostertagia Ostertagi
Parasitology, 2004Co-Authors: V. De Maere, Jozef Vercruysse, Peter Geldhof, Isabel Vercauteren, Kris Gevaert, Edwin ClaereboutAbstract:In this study, we describe the Molecular analysis of zinc-metalloproteases from the abomasal nematode Ostertagia Ostertagi which were exclusively recognized by local antibodies of immune cattle. Full-length or partial coding sequences of 4 different zinc-metalloprotease cDNAs of Ostertagia (met-1, -2, -3 and -4) were amplified using gene-specific primers using the 3'- and 5'-Rapid Amplification of cDNA Ends (RACE) technique. Sequence analysis identified the cDNAs as encoding zinc-metalloproteases, which showed between 62%, and 70% homology to a metalloprotease 1 precursor of Ancylostoma caninum. The full-length cDNA of met-1 consists of an open reading frame (ORF) of 586 amino acids which contains 5 potential N-glycosylation sites and a predicted zinc-binding domain (HEBXHXBGFXHEXXRXDRD). The complete coding sequence of met-3 contains an ORF of 508 aa and the same conserved zinc-binding domain. These domains are signature sequences of the astacin family of the superfamily of metzincin metalloproteases. The presence of a threonine amino acid after the third histidine in M ET-l and MET-3, however, may place them in a new family or subfamily. Real-time PCR analysis of L3, exsheathed L3, L, and adult cDNA identified transcription of the 4 metal lop roteases in different life-stages. The protein MET-1 was expressed in insect cells using the baculovirus expression system but the immunization of calves with this molecule did not lead to protection against challenge infection.
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proteinases released in vitro by the parasitic stages of the bovine abomasal nematode Ostertagia Ostertagi
Parasitology, 2000Co-Authors: Peter Geldhof, Joost Agneessens, Edwin Claerebout, D Knox, Jozef VercruysseAbstract:Host tissue penetration, feeding and immune evasion by helminth parasites may be mediated by both mechanical processes and histolytic products released by the parasite. The aim of this study was to investigate potential histolytic products released during in vitro maintenance of exsheathed third (L3) and 4th larval stage (L4) and adult Ostertagia Ostertagi. Therefore, the pH optima, substrate specificity, molecular size and inhibitor sensitivity of in vitro released (IVR) proteinases were analysed by spectrophotometry and substrate gel electrophoresis. It was shown that L3, L4 and adult IVR proteinases degrade a variety of protein substrates in a pH-dependent and stage-specific manner. At alkaline pH, gelatin, casein and fibrinogen were degraded by metallo- and serine proteinases. In contrast, mucin, fibrinogen, albumin and haemoglobin were degraded at acidic pH by aspartyl protease- and cathepsin L-like activity. At pH 3, the heavy chain of bovine IgG was completely degraded by an aspartyl proteinase secreted by all 3 parasitic stages. The specificity of the L3, L4 and adult Ostertagia Ostertagi proteinases against the different substrates indicates variable functional requirements.
J C Williams - One of the best experts on this subject based on the ideXlab platform.
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Epidemiology of Ostertagia Ostertagi in weaner-yearling cattle.
Veterinary Parasitology, 1993Co-Authors: J C Williams, J.w. Knox, A.f. LoyacanoAbstract:Epidemiologic events in the life cycle of Ostertagia Ostertagi are best known in the weaner-yearling phase of cattle development throughout the concentrated cattle-rising areas of the world. Animal and pasture management demands placed on this age class are greater than for suckling calves and adult stock in either beef or dairy breeds. This fact alone would likely account for a higher prevalence of clinical and subclinical disease in weaner-yearlings. Additionally, the developing immune response provides relatively early protection against intestinal genera such as Cooperia and Oesophagostomum, but is delayed against Ostertagia Ostertagi and Trichostrongylus axei. Both Type I and Type II disease may occur within the weaner-yearling stage. Factors affecting population changes of Ostertagia Ostertagi have been described as extrinsic, i.e. weather-climate and grazing management, and intrinsic or host factors, i.e. age, sex, immune status, heredity and reproductive state. Immune status, particularly in weaner-yearlings, may be of primary importance, as affected by host and extrinsic factors. With slow development of protective immunity against Ostertagia Ostertagi in calves, the possible role of immunity in both induction of inhibition and larval maturation, the potential immunopathologic involvement in pathogenesis of Type II disease, hypersensitivity to larval intake in resistant adult cows, and the reported delay of a protective response following anthelmintic prophylaxis in younger cattle, the immune response may have profound influence on epidemiologic variation through age classes. Although continual epidemiological observations from birth to early adulthood in the same cattle have not been undertaken, some notable studies in the UK, the Netherlands, and Denmark have closely examined epidemiological events through first and second grazing seasons.
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Efficacy of abamectin against natural infections of gastrointestinal nematodes and lungworm of cattle with special emphasis on inhibited, early fourth stage larvae of Ostertagia Ostertagi.
Veterinary parasitology, 1992Co-Authors: J C Williams, A.f. Loyacano, C. Nault, R.t. Ramsey, R.e. PlueAbstract:The anthelmintic efficacy of abamectin (avermectin B1) was evaluated against gastrointestinal nematodes, including Ostertagia Ostertagi inhibited larvae and lungworm, in yearling crossbred beef heifers during late spring. The calves were grazed on contaminated pasture for 10 weeks and then held under conditions free of nematode infection for 3 weeks prior to allotment and treatment on 5 June. Thirteen calves were randomly assigned to two groups of six by restricted randomization on body weights; the extra lightest calf was assigned to the non-treated control group. Group 1 calves were treated with abamectin at 200 micrograms kg-1 body weight by s.c. injection and Group 2 calves were not treated; all were killed at 14 days after treatment. Ostertagia Ostertagi was present in all controls; arithmetic mean numbers of adults, developing fourth stage larvae (L4) and inhibited EL4 were 7683, 605 and 36,102, respectively. Other nematode genera present in controls in sufficient numbers for the experiment were Haemonchus placei adults, Trichostrongylus axei adults, Cooperia spp. adults, Oesophagostomum radiatum adults, Bunostomum phlebotomum adults, Dictyocaulus viviparus adults and E5 (immature adults). Abamectin was highly effective (consistently greater than 99% efficacy and P less than 0.05) in removing all nematodes present in treated calves as represented in non-treated controls, including the primary target of Ostertagia Ostertagi inhibited EL4. The lowest efficacy was 93.8%, against D. viviparus E5.
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Efficacy of levamisole against Ostertagia Ostertagi in Louisiana cattle during maturation of inhibited larvae (September) and during minimal inhibition (December/January)☆
Veterinary parasitology, 1991Co-Authors: J C Williams, J.w. Knox, K.s. Marbury, R.a. Swalley, C.s. EddiAbstract:Levamisole (LEV) was tested in four experiments to compare efficacy values against Ostertagia Ostertagi when larval maturation was occurring (September), following inhibition and also when populations were expected to be largely adult (winter). A primary objective was to determine the importance of developing fourth-stage larvae (DL4) and inhibited, early fourth-stage larvae (EL4) in replacing adult worms lost through treatment and the effect of this on reduced efficacy against adult worms. Young crossbred beef calves ranging in weight from 150 to 230 kg were used in the first (September 1981), second (September 1983) and third experiments (January 1987). Jersey calves of 110 kg average weight were used in the fourth experiment (December 1988). Calves were randomized to groups according to weight and group sizes ranged from three to five calves. All parasite infections were naturally acquired, but a mixture of nematode third-stage larvae (L3) (22,500 per calf), including 20% Ostertagia Ostertagi, was inoculated into Jersey calves of Experiment 4 following a 2 week exposure to natural infection. All LEV treatments were by subcutaneous injection at dosages of 6 and 8 mg kg-1. Treatment with ivermectin was used only in Experiment 3 as an efficacy reference. All calves were killed at 8-10 days after treatment. The efficacy of LEV against all developmental stages of Ostertagia Ostertagi was consistently low in all experiments and a dose-dependent response was not evident. Large numbers of all Ostertagia Ostertagi developmental stages were present in non-treated calves in both September experiments. Percent reduction of adults, DL4 and EL4 at the 6 mg kg-1 and 8 mg kg-1 dosages, respectively, were adults, 51.7 and 23.6 (1981), 8.7 and 51.3 (1983); DL4 40.3 and 13.2 (1981), 37.9 and 33.1 (1983); EL4, 19.6 and 0 (1981), 59.6 and 42.9 (1983). Smaller numbers of Ostertagia Ostertagi were present in winter experiments and adult worms greatly outnumbered larval stages. Percent reductions of adults, DL4 and EL4, respectively, were (1987) LEV 6 mg kg-1, 40.2, 0 and 0; ivermectin 200 micrograms kg-1, 98.7, 97.7 and 100.0; (1988) LEV 6 mg kg-1, 62.4, 100.0 and 100.0; LEV 8 mg kg-1, 49.1 65.0 and 74.1. Too few larval stages were present in the latter experiment for valid efficacy values.(ABSTRACT TRUNCATED AT 400 WORDS)
Markus Drag - One of the best experts on this subject based on the ideXlab platform.
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the level of embryonation influences detection of Ostertagia Ostertagi eggs by semi quantitative pcr
Parasites & Vectors, 2016Co-Authors: Johan Hoglund, Markus Drag, Peter Nejsum, S M Thamsborg, Heidi L EnemarkAbstract:The Internal Transcribed Spacer 2 (ITS2) is a candidate diagnostic marker of the pathogenic cattle nematode Ostertagia Ostertagi. The aims of this study were: (i) to document and quantify how the development of O. Ostertagi eggs affects ITS2 copies under different storage conditions, and (ii) to suggest optimal storage conditions for faecal samples in a diagnostic pipeline that involves detection and semi-quantification by real-time semi-quantitative polymerase chain reaction (qPCR). Eggs of Ostertagia Ostertagi were obtained from fresh faeces and stored at 4 °C or 25 °C under aerobic or anaerobic (vacuum packing) conditions. Development was monitored by microscopy for up to 336 h, and the ITS2 copies were determined by qPCR from a fixed number of parasites. Under aerobic conditions at 25 °C, embryonation and a significant increase of ITS2 copies (P < 0.0001) were observed after 12 h. At 4 °C, embryonation occurred after 168 h with a trend towards increased ITS2 copies. Anaerobic conditions inhibited egg development at both temperatures and no significant increase in ITS2 copies was noticed (P = 0.90). ITS2 copies were analysed for each parasite stage: first-stage larvae (L1) exhibited significantly higher copy numbers (20,353 ± 1,950) than unembryonated eggs (568 ± 168; P < 0.0001) with lower coefficient of variation (33 vs 266 %). Aerobic storage of O. Ostertagi eggs at 25 °C led to a significant increase in ITS2 copies after 12 h due to embryonation and subsequent hatching. In contrast, anaerobic storage (vacuum packing) at 25 °C completely inhibited egg development and any undesirable semi-quantification bias for up to 336 h. Hence, vacuum packing is an optimal storage strategy prior to molecular diagnostic analyses. Alternatively, aerobic storage at 4 °C for up to 72 h can be used. Due to high copy numbers and lower genetic variation, the L1 stage may be considered for diagnostics and further molecular research.
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Additional file 2: of The level of embryonation influences detection of Ostertagia Ostertagi eggs by semi-quantitative PCR
2016Co-Authors: Markus Drag, Johan Hoglund, Peter Nejsum, S M Thamsborg, Heidi L EnemarkAbstract:Alignment of 49 ITS2 sequences from Ostertagia Ostertagi obtained from BLAST on the O. Ostertagi ITS2 sequence (GenBank AB245021.2|: 1,036–1,126 bp) targeted by the qPCR developed by Höglund et al. [15] and used in this study. Primers and probe are aligned in the bottom. Asterisks indicate the complete nucleotide conservation throughout all sequences; 15 sequences (31 %) contained single nucleotide polymorphisms (SNPs) in the forward primer region. (DOC 35 kb
