Sanitary requirements for bovine gametes and embryos in ... - CBRA
Sanitary requirements for bovine gametes and embryos in ... - CBRA Sanitary requirements for bovine gametes and embryos in ... - CBRA
Ponsart and Pozzi. Sanitary requirements for gametes and embryos.Table 5. Assessment of the sanitary risk for in vivo derived embryos using scientific approaches.In vivo infectionIn vitro infectionIn vivo embryotransfer• naturally infected donor or inseminationwith infected semen;••experimentally spiked embryos/semen;embryos transferred to recipients.In vitro embryowashing• Embryos transferred to recipients.• naturally infected donor or inseminationwith infected semen;• embryo status analyzed after washingprocedure described in IETS Manual.• experimentally spiked embryos/semen;• embryo status analyzed after washingprocedure in IETS Manual.Concerning transmission risk via ET, the IETSHASAC Committee reviews scientific publications onan annual basis and updates a complete set of more than400 references, which can be consulted on their website(www.iets.org). In the bovine species, 89 potentialembryo pathogens have been investigated (Thibier,2011). All diseases and pathogenic agents have beenplaced into one of four categories based on the amountof research indicating the likelihood of disease controlthrough the use of embryo transfer (Table 6). Forcategory 1 diseases, risk of transmission of a givendisease from donor to recipient via an embryo isnegligible, providing biosecurity measures describedfor handling embryos, material disinfection, and animalhealth requirements (semen, donor, and recipients ) asdescribed in the IETS Manual have been respected(Stringfellow, 2010; Thibier, 2011).New questions have been raised regardingtrypsin treatments: Al Ahmad et al. (2012) compared atreatment standard (TS) comprised of phosphate-bufferedsaline (PBS), 0.4% BSA (five washes of 100 fold dilutionfor 10 sec each), followed by two treatments with 0.25%trypsin in Hank’s solution (45 sec each), and then PBS0.4% BSA again (five times for 10 sec). The four otherwashing procedures all included the same first and lastwashing steps with PBS but without BSA (five times for10 sec) and with PBS 0.4% BSA (five times for 10 sec),respectively. The intermediate step varied for each washingprocedure, with other trypsin treatments (longer time, twicefor 60 sec) or hyaluronidase treatments in order toeliminate Blue tongue virus (BTV) from in vitro infectedgoat embryos: only two trypsin treatments of 60 sec eachwas effective in removing BTV from the embryos.Legal and sanitary measures applied to in vivoderived embryosPractical guidelines have been published in theManual of the International Embryo Transfer Society inorder to provide risk management procedures ensuringthe safety of ET (Stringfellow, 2010). Since theseguidelines have been adopted by the OIE, they are wellaccepted and implemented worldwide (OIE, 2012;Chapter 4.7). In Europe, legislation prescribes thesanitary conditions to which embryo collection andtransfer should comply. The Council Directive89/556/EEC of 25 September 1989 describes animalhealth conditions governing intra-community trade inand importation from third countries of embryos derivedfrom the bovine species. The legislation defines sanitaryand biosecurity requirements including donor females,environmental and handling conditions, and semen usedfor donor insemination.• Sanitary requirementsIn addition to OIE recommendations (Table 7),EU legislation includes the following requirements:donor cows must have spent the previous 6 monthswithin community territory or in the third country ofcollection in a herd officially tuberculosis and brucellosisfree, enzootic bovine leucosis free (or no clinical signs ofenzootic bovine leucosis during the previous 3 years);and where no clinical signs of infectious bovinerhinotracheitis/infectious pustular vulvo-vaginitis havebeen observed during the previous year.• Environmental and handling conditionsBoth the OIE Terrestrial Code (Chapter 4.7)and Directive 89/556 include biosecurity measures basedon a team approved by competent authority (governmentor local veterinary authorities), supervised by a teamveterinarian responsible for all team operations (healthstatus of donor cows, appropriate disease control measureswith handling and operating on donors, disinfection, andhygiene procedures). Team personnel should be adequatelytrained in the techniques and principles of disease control.High standards of hygiene should be practiced topreclude the introduction of disease.Procedures, facilities, and equipment are verifiedthrough regular official inspections (at least once a year)regarding embryo collection, process, and manipulation ofembryos at a permanent site or mobile laboratory, storageof embryos as well as activity records.The testing of samples can be requested by animporting country to confirm the absence of pathogenicorganisms that may be transmitted via in vivo derivedembryos (see Table 9), or to assess the quality control ofthe collection team together with washing procedures.Specimens may include degenerated embryos, embryocollection fluids, and a pool of the last washes of theembryos. In the French regulations, this testingprocedure is performed annually in a central laboratory290 Anim. Reprod., v.10, n.3, p.283-296, Jul./Sept. 2013
Ponsart and Pozzi. Sanitary requirements for gametes and embryos.and represents a prerequisite of renewal of approvaltogether with a favorable report from the officialinspection (France, 2008).• Sanitary controls of semen used in embryotransferThe safety of semen is another critical point andinternational regulations include requirements regardingejaculates being used for assisted reproduction techniques(Wrathall et al., 2006). With regard to semen that is used toproduce embryos for international trade, batches of frozensemen are selected from bulls located in accredited AICenters in the majority of cases. Such bulls are normallycertified negative for acute, epidemic diseases such as footand-mouthdisease, and chronic diseases such asbrucellosis, tuberculosis, leptospirosis, campylobacteriosis,and trichomonosis. For international trade, some countriesrequest that bulls are certified negative for enzootic bovineleukosis, infectious bovine rhinotracheitis, and bovine viraldiarrhea. (Bielanski, 2006; Wrathall et al., 2006).Table 6. Diseases or infectious agents in cattle listed by IETS according to the risk for their transmission via in vivoderived embryos (OIE, 2012).Disease categoryDisease agentCategory 1:BluetongueSufficient evidence has accrued to show that the risk of Bovine spongiform encephalopathytransmission is negligible provided that the embryos are Brucella abortusproperly handled between collection and transfer Enzootic bovine leukosisaccording to the IETS Manual.Foot and mouth diseaseInfectious bovine rhinotracheitis: trypsin treatment requiredCategory 2:Substantial evidence has accrued to show that the risk oftransmission is negligible provided that the embryos areproperly handled between collection and transferaccording to the IETS Manual, but for which additionaltransfers are required to verify existing data.Category 3:Preliminary evidence indicates that the risk oftransmission is negligible provided that the embryos areproperly handled between collection and transferaccording to the IETS Manual, but for which additionalin vitro and in vivo experimental data are required tosubstantiate the preliminary findings.Category 4:No conclusions are yet possible with regard to the levelof transmission risk, or the risk of transmission viaembryo transfer might not be negligible even if theembryos are properly handled according to the IETSManual between collection and transfer.Requirements applicable to in vitro produced (IVP)embryosAssessment of disease transmission via in vitroproduced embryosIn vitro embryo production entails thecompletion of three biological steps that are now wellNoneBovine immunodeficiency virusBovine viral diarrhea virusRinderpest virusCampylobacter fetus (subs. veneralis)Haemophilus somnusMycobacterium paratuberculosisNeospora caninumAkabaneBovine anaplasmosisBovine herpesvirus-4EnterovirusLumpy skin diseaseVesicular stomatitisChlamydia psittaciEscherichia coli 09:K99Leptospira borgpetersenii serovar hardjobovisMycobacterium bovisParainfluenza-3 virusTrichomonas foetusUreaplasma and Mycoplasma spp.established in cattle: oocyte maturation, in vitrofertilization (IVF), and embryo culture. The followingfactors have hindered progress toward the establishmentof recognized sanitary procedures for IVP embryos.The zona pellucida of intrafollicular oocytesappears to differ from that of ovulated ova. This structuraldifference might be associated with differing resistance toadherence to or penetration of the zona pellucida byAnim. Reprod., v.10, n.3, p.283-296, Jul./Sept. 2013 291
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Ponsart <strong>and</strong> Pozzi. <strong>Sanitary</strong> <strong>requirements</strong> <strong>for</strong> <strong>gametes</strong> <strong>and</strong> <strong>embryos</strong>.<strong>and</strong> represents a prerequisite of renewal of approvaltogether with a favorable report from the official<strong>in</strong>spection (France, 2008).• <strong>Sanitary</strong> controls of semen used <strong>in</strong> embryotransferThe safety of semen is another critical po<strong>in</strong>t <strong>and</strong><strong>in</strong>ternational regulations <strong>in</strong>clude <strong>requirements</strong> regard<strong>in</strong>gejaculates be<strong>in</strong>g used <strong>for</strong> assisted reproduction techniques(Wrathall et al., 2006). With regard to semen that is used toproduce <strong>embryos</strong> <strong>for</strong> <strong>in</strong>ternational trade, batches of frozensemen are selected from bulls located <strong>in</strong> accredited AICenters <strong>in</strong> the majority of cases. Such bulls are normallycertified negative <strong>for</strong> acute, epidemic diseases such as foot<strong>and</strong>-mouthdisease, <strong>and</strong> chronic diseases such asbrucellosis, tuberculosis, leptospirosis, campylobacteriosis,<strong>and</strong> trichomonosis. For <strong>in</strong>ternational trade, some countriesrequest that bulls are certified negative <strong>for</strong> enzootic <strong>bov<strong>in</strong>e</strong>leukosis, <strong>in</strong>fectious <strong>bov<strong>in</strong>e</strong> rh<strong>in</strong>otracheitis, <strong>and</strong> <strong>bov<strong>in</strong>e</strong> viraldiarrhea. (Bielanski, 2006; Wrathall et al., 2006).Table 6. Diseases or <strong>in</strong>fectious agents <strong>in</strong> cattle listed by IETS accord<strong>in</strong>g to the risk <strong>for</strong> their transmission via <strong>in</strong> vivoderived <strong>embryos</strong> (OIE, 2012).Disease categoryDisease agentCategory 1:BluetongueSufficient evidence has accrued to show that the risk of Bov<strong>in</strong>e spongi<strong>for</strong>m encephalopathytransmission is negligible provided that the <strong>embryos</strong> are Brucella abortusproperly h<strong>and</strong>led between collection <strong>and</strong> transfer Enzootic <strong>bov<strong>in</strong>e</strong> leukosisaccord<strong>in</strong>g to the IETS Manual.Foot <strong>and</strong> mouth diseaseInfectious <strong>bov<strong>in</strong>e</strong> rh<strong>in</strong>otracheitis: tryps<strong>in</strong> treatment requiredCategory 2:Substantial evidence has accrued to show that the risk oftransmission is negligible provided that the <strong>embryos</strong> areproperly h<strong>and</strong>led between collection <strong>and</strong> transferaccord<strong>in</strong>g to the IETS Manual, but <strong>for</strong> which additionaltransfers are required to verify exist<strong>in</strong>g data.Category 3:Prelim<strong>in</strong>ary evidence <strong>in</strong>dicates that the risk oftransmission is negligible provided that the <strong>embryos</strong> areproperly h<strong>and</strong>led between collection <strong>and</strong> transferaccord<strong>in</strong>g to the IETS Manual, but <strong>for</strong> which additional<strong>in</strong> vitro <strong>and</strong> <strong>in</strong> vivo experimental data are required tosubstantiate the prelim<strong>in</strong>ary f<strong>in</strong>d<strong>in</strong>gs.Category 4:No conclusions are yet possible with regard to the levelof transmission risk, or the risk of transmission viaembryo transfer might not be negligible even if the<strong>embryos</strong> are properly h<strong>and</strong>led accord<strong>in</strong>g to the IETSManual between collection <strong>and</strong> transfer.Requirements applicable to <strong>in</strong> vitro produced (IVP)<strong>embryos</strong>Assessment of disease transmission via <strong>in</strong> vitroproduced <strong>embryos</strong>In vitro embryo production entails thecompletion of three biological steps that are now wellNoneBov<strong>in</strong>e immunodeficiency virusBov<strong>in</strong>e viral diarrhea virusR<strong>in</strong>derpest virusCampylobacter fetus (subs. veneralis)Haemophilus somnusMycobacterium paratuberculosisNeospora can<strong>in</strong>umAkabaneBov<strong>in</strong>e anaplasmosisBov<strong>in</strong>e herpesvirus-4EnterovirusLumpy sk<strong>in</strong> diseaseVesicular stomatitisChlamydia psittaciEscherichia coli 09:K99Leptospira borgpetersenii serovar hardjobovisMycobacterium bovisPara<strong>in</strong>fluenza-3 virusTrichomonas foetusUreaplasma <strong>and</strong> Mycoplasma spp.established <strong>in</strong> cattle: oocyte maturation, <strong>in</strong> vitrofertilization (IVF), <strong>and</strong> embryo culture. The follow<strong>in</strong>gfactors have h<strong>in</strong>dered progress toward the establishmentof recognized sanitary procedures <strong>for</strong> IVP <strong>embryos</strong>.The zona pellucida of <strong>in</strong>trafollicular oocytesappears to differ from that of ovulated ova. This structuraldifference might be associated with differ<strong>in</strong>g resistance toadherence to or penetration of the zona pellucida byAnim. Reprod., v.10, n.3, p.283-296, Jul./Sept. 2013 291
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