Welcome to topic 3 for 624EHS - Contemporary Issues in Equine Science.
This topic is all about Equine Vaccinations. Make sure that you look at the launch powerpoint, which has been posted in the Classroom. All distance learning students are required to contribute to this blog. You have from now until 2 pm on Wednesday 15th of January 2020 to contribute to this blog, to debate the issues surrounding Equine Vaccinations. Ensure you can also evidence your opinions and remember that you are also required to submit a reference list (word document emailed to module leader) by 2 pm on Wednesday 15th of January. You will be graded on the quality and quantity of both your blog contributions and your reference list. Remember, the point of this is to debate the issues, so you should be replying to each other's posts. I will be keeping an eye on the blog, but if you have any issues, you should email me. Please note that this topic 3, will be marked and will count towards your final coursework 3 mark. Please remember to register your name with your comments so that I know who has contributed with which comment.
Rosa
Vaccinations play a critical role in preventing disease in equids by “reducing the risk of a disease outbreak occurring, reducing the spread of disease in the event of an outbreak and by decreasing the severity of illness in affected animals” (BHS, 2019)
ReplyDeleteA vaccination is designed to train the body’s immune system in order to enable it to recognise and combat the pathogens (either viruses or bacteria) of a disease it has not encountered prior (Oxford Vaccine Group, 2019; Public Health, 2019). In order to do this, “certain molecules from the pathogen must be introduced into the body to trigger an immune response” (Public Health, 2019).
Vaccinations are a controversial topic of discussion across a variety of communities, with questions posed surrounding the efficacy of vaccinating both humans and animals. Vaccines can be categorised into two groups - live attenuated vaccines, or inactivated whole cell vaccines (Malan, 2017; World Health Organisation, nd).
While inactivated vaccinations are produced from microorganisms that have been killed in either a physical or chemical process, live vaccinations are procured from pathogens which have been weakened under laboratory conditions and therefore continue to grow in the individual in which it was administered (WHO, nd). It should be noted here that while live vaccines have the ability to cause mild disease in the individual, owing to the weakening process and intensive testing associated with the approval process, it has been established that the overall benefits outweigh the potential side effects (Rettner, 2017). Additionally, only 1 year prior to the 2019 equine influenza outbreak in the UK, a study concluded that live equine flu vaccinations provide better immune responses and longer periods of protection against the disease than their inactivated counterparts (Rodriguez et al., 2018).
Equine influenza and tetanus are only two of the many equine specific diseases that are vaccinable. Vets and professional bodies recommend that all horses in the UK are at least vaccinated against these diseases (BHS, 2019; Rossdales Veterinary Surgeons, nd), with additional vaccinations against diseases such as equine herpes virus and equine rotavirus dependent on individual circumstances such as potential exposure within competition, international travel and breeding status (Bateman, 2019; Rossdales Veterinary Surgeons, nd).
All horses are exposed to a range of viral and bacterial infectious disease risks every day, which, if a horse becomes infected it not only impacts their health and welfare but also causes a disruption in competition and breeding schedules. The risk is significantly increased in horses that travel to events where large numbers of horses interact. Vaccinations against commonly occurring equine diseases such as equine influenza and tetanus are vital not only to reduce the risk of infection but as a mandatory requirement to enable horses to compete in equine events while protecting the wider equine population and industries.
ReplyDeleteThe use of vaccinations can reduce the risk of disease outbreaks, reduce the spread of disease during an outbreak or reduce the severity of illness in affected horses (Beva.org.uk, 2020; Bhs.org.uk, 2020; NOAH, 2020). It is strongly advised that all horses should be vaccinated against tetanus, a severe and fatal disease caused by the bacteria Clostridium tetani. This bacteria is found in soil, and if it enters the horse's body via a wound, a toxin is produced, which in turn affects the nervous system. As the disease progresses, it causes muscle spasms, paralysis of the muscles used for breathing, and eventually death. With appropriate vaccinations, the risk of tetanus is significantly reduced, improving the health and welfare of horses (Bhs.org.uk, 2020; FEI, 2020).
Vaccinating against equine influenza is a common practice in the equine industry. Equine influenza is a highly contagious viral respiratory disease. Outbreaks can spread rapidly because it can be spread by airborne nasal secretions, direct contact, and indirect contact via handlers and fomites. Outbreaks such as the 2019 outbreak, where there were 228 outbreaks of the disease (Equiflunet, 2020) demonstrate the importance of vaccinating horses. A large number of unvaccinated horses accelerated the spread of disease. Although vaccinations can not provide total protection from the disease, horses who are vaccinated will display reduced clinical signs and have a faster recovery. They will also spread less virus, meaning other horses will be less likely to get sick (Aht.org.uk, 2020). As a result of the 2019 outbreak, it was advised to vaccinate horses every six months instead of yearly, in an attempt to reduce the spread of the disease (HBLB, 2020).
Vaccination programs include primary courses and boosters, which are intended to be followed to meet the manufacturer's recommendations. For horses that compete, it is necessary for them to receive the required vaccinations, and it is recorded in their passport. The FEI states that "Horses must be vaccinated against equine influenza in order to compete at FEI events. Every horse's passport is checked at events to ensure that the horse has been vaccinated according to the FEI Veterinary Regulations. Therefore all equine influenza vaccines that have been given to the horse must be recorded in the horse's passport." (FEI, 2020). As a result, horse owners need to comply with vaccination programs to be able to compete with their horses. At lower level competitions and events, it is not always enforced to provide proof of vaccinations, which often leads to horses gathering in large numbers who have not received necessary vaccinations. Cases such as in 2019, showed that large numbers of horses that are unvaccinated increases the spread of diseases.
Equine influenza virus (EIV) breakouts continue to disrupt the equine industry across the world despite vaccination protocols and bio security strategy implementation (Pavulraj et Alan 2017). Another virus, Equine herpes virus (EHV), causes pregnant mares to abort thier unborn foals. In 2016, 10 vaccinated mates contracted EHV and aborted thier foals. Despite the horses receiving vaccinations the disease prevailed and infected the hosts (Garnett, 2017). The outbreaks are an indication of the vaccination process breaking down. Weaknesses in the vaccination itself along with the vaccination protocol need to be investigated to determine the cause of the outbreaks and review current procedures with the aim to prevent future outbreaks.
ReplyDeleteVirus mutations constantly occur therefore vaccinations need to be revised to match current strains. It has been suggested the vaccinations are not able to be modified at the same rate of the mutations which has contributed to the outbreaks of EIV. Horses have not been adequately vaccinated against the most recent mutations of the disease. (Durham, 2019).
EIV outbreaks have been linked to biosecurity breaches and reduced vaccination frequency compliance. 66.7% of horses that contracted EIV had not had a equine influenza vaccination in the last six months before developing symptoms. 37% of horses were due a yearly vaccination when they started to show symptoms of the respiratory disease EIV (Gildea, 2018). Vets typically recommended vaccinating once a year however FEI competition rules require vaccination every 6 months. Since the 2019 EIV outbreaks the vets guides me has changed and have recommend the 6 months vaccination. Further research into the efficacy and longevity of vaccine protection should be investigated in order for equine owners to be advised accordingly to help prevent the spread of the disease.
In partial agreement with the other comments, vaccination has been showed as an efficient method of controlling disease, both with regard to its spread, and impact on the horse, as well as the economic cost of vaccination versus veterinary care, loss of use, and even possible destruction of the horse (Humblet et al., 2016; Paillot et al., 2017; Sack et al., 2019).
ReplyDeleteThough there is no actual legal requirement to vaccinate in the UK (NOAH, 2019), it is a requirement of the various competitive authorities (FEI, 2019; Jockey Club, 2019; BD, 2019, BE, 2019, BSJA, 2019). However, it may become a legal issue, under the provisions of the Animal Welfare Act 2006, where it could be used to infer that by not vaccinating a horse, you are in breach of article 9 referring to the horse's need to be protected from pain, suffering, injury and disease (UK Gov., 2019).
The basic requirements are for the EI vaccination, generally followed (on recommendation) by that for Tetanus. The former is a requirement to compete, travel and in general participate in equestrian activities. Most stables also require vaccinations to be up-to-date before permitting horses to stay (BHS, 2019). Other vaccines are available for the following diseases; EHV-1 and EHV-4, EVA, Equine Rotavirus, Strangles (NOAH, 2019).
The impact of not vaccinating has been recently showed by the EI outbreak in the UK in 2019, where the majority of infected horses were not vaccinated for EI (AHT, 2020). The cost of this has been estimated at £100 - 200 million for the horse racing industry alone (Wilson, 2019).
While the debate is still out on whether vaccination is the correct method of disease control, considering the possible side effects from immunisation of horses, albeit minimal (Barba et al., 2019; Rosanowski et al., 2019). Other research indicates that the alternative is disastrous without this, as the Australian EI outbreak in 2007 showed (Fougerolle et al., 2019; Rosanowski et al., 2019).
Further research into improving the efficacy and keeping vaccines up to date with the disease's mutations is certainly necessary. However, other solutions should also be looked into, such as the use of homeopathic nosodes (Doehring & Sundrum, 2016; Epstein & Bell, 2016; Lees et al., 2017; Dennis et al., 2018), which still struggle to gain scientifically replicable results (Loeb et al., 2018).
Another avenue worth looking at is the immunisation of the vector reservoir for diseases, thus reducing the source of the disease itself (Afrough et al., 2019), as well as applying molecular techniques to virology (ibid).
I wholeheartedly agree with Charlotte about evidence indicating weaknesses within the protocol and the need for review. Recent reports regarding the current EHV outbreak in Hampshire further support the notion of flawed biosecurity measures (Murray, 2020).
ReplyDeleteRegarding EIV - of the 66.7% of horses that contracted EIV who had not had a jab in the 6 months prior to developing symptoms, does that figure account for horses which were exempt from the recommendation of 6 monthly vaccination? Is the remaining 33.3% who were vaccinated but still presented symptomatic, further indicative of weaknesses and inefficiencies even in “improved” protocols calling for twice annual vaccination?
Additionally, the impact that 6 monthly vaccinations could have on the veterinary industry should be considered. With many practices already working with stretched resources, could this change mean that vets will be subject to further time constraints? Or could it mean that there is an overall increase in their business, resulting in an increased generation of revenue? The latter is certainly questionable given the relatively low cost to owners of vaccinations when compared to horse ownership as a whole (BHS, 2019), along with cost saving incentives such as vet’s “zone days”. And is there an argument that further exposure to dated vaccines simple accelerate the rate in which these vaccinations become weaker and therefore less efficient? Surely access to more advanced EIV vaccinations than the 25 year old ones are needed? (University of Rochester Medical Center, 2018)
Aspects of the 2019 EIV outbreak were entirely unprecedented, with reports of airborne spread of the disease (Elder, 2019). As a result, could it be argued that the industry was, and still is, unprepared to effectively handle an outbreak? In addition, these changes are demonstrative of the difficulty that owners face when trying to work out the statistical significance of vaccinating vs risk of contraction. For example, the owner whose horse does not leave their yard believing that said horse does not require vaccinations, yet the risk of tetanus is evident regardless, as noted in Amber’s comments about the source of Clostridium tetani.
Simon makes an extremely valid point surrounding the legality of the requirement to vaccinate. However, the question of how a change in law would be implemented is considerable, given the difficulties authorities can face when prosecuting even the most heinous of crimes against animals. Additionally, what would the stance be regarding those horses who experience adverse side effects to vaccinating? Would vaccinating them be contradictory of their protection from pain and suffering? However, would the exemption of these horses adversely contradict the concept of ‘herd immunity’?
Finally, furthermore to the list of vaccinable diseases mentioned by Simon, I would like to add that additional vaccinations are available against West Nile virus, Sleeping sickness, Rabies, Potomac horse fever, Equine rhinitis A virus, with the Strangles vaccine being available within the UK as of 2020 (Bateman, 2019; Boehringer Ingelheim, nd). In addition, whilst acknowledging that EHV has nine strains, EHV1 and EHV4 are the two that cause disease, and are therefore vaccinated against (Phillips, 2020). It should be noted that the effects of the virus are dependent on the strain, and that while vaccines are advantageous against the respiratory effects of EHV, “they are not registered for use against the paralytic form” (Phillips, 2020).
Taking Robyn's point with regard to owners who are reticent in vaccinating their horse, reseach by Manyweathers et al. (2017), indicate 3 principle barriers to vaccine uptake, these being vaccine safety, costs and effectiveness. Obviously, if vets offer cost saving incentives, then this could remove one barrier. The worry of safety, and negative side effects from vaccination would indicate that more studies need to be done to remove potential allergens from the vaccine, these generally being protein-based adjuvants used as carriers for the vaccine itself (Gershwin, 2018). This further adds weight to Afrough et al. (2019)'s consideration that molecular and genetical technologies need to be used to improve the effectiveness and safety of vaccines. This is shown by research which indicates that vaccination against Influenza viruses is not effective (Debbink et al., 2017).
ReplyDeleteThis is in part in progress as the research for new EIV vaccines are coming about (Blanco-Lobo et al., 2019). Combining this with research into the ways to reduce or immunise horses against hypersensitivity, and thus reactivity to other substances (Fettelschoss-Gabriel et al., 2019), could be a way forward to improving vaccine safety, and removing another barrier to horse owner reticence.
With regards to comments regarding other disease outbreaks, EHV this month in UK (AHT, 2020), other diseases are worrying such as Viral Equine Encephalitis, caused by several equine diseases including rabies and WNV (Lecollinet et al., 2020), and for which I wholeheartedly concur that more needs to be done regarding biosecurity, which is not only reliant on vaccination. This includes rapid recognition of symptoms, thus limiting movement and the spread of diseases. A recent survey in the UK has shown that low numbers of horse owners are aware of possible disease vectors like mosquitoes (31-36%), while only between 12 and 13% can indicate symptoms linked to African Horse Sickness (AHS) or WNV (Chapman et al., 2018).
So sensitisation is also a very import pillar to supporting the control of diseases.
In the UK there are currently 5 main exotic disease risks which have a detrimental affect the welfare of the horse in various ways depending on the disease contracted. However, only some of these top 5 diseases have a vaccination developed as part of a prevention of disease plan. As Simon previously mentioned, vectors such as mosquitoes or insect vectors can spread diseases such as Equine Infectious Anaemia (EIA), African Horse Sickness and West Nile Virus (MSD, 2019). Biosecurity protocols could help reduce the number of insect convectors, thus reducing the spread of the said diseases.
ReplyDeletePreviously Simon highlighted the disastrous EI Australian outbreak in 2007. The outbreak was traced back to poor biosecurity measures in the quarantine station of racehorses (Sack, 2019). Firestone et al (2011) found that farms which had a high compliance of farm biosecurity measures prevented horses in high outbreak areas becoming infected with EI. The outbreak in 2007 highlights the importance of high compliance of biosecurity protocols. Biosecurity measures are often overlooked with too much reliance on the vaccination alone for prevention of outbreaks (Ivens et al, 2019). Vaccination against EI has become a common procedure in the industry, perhaps giving a false perception of efficacy of prevention of EI amongst horse owners. Animal Health Trust identified that vaccination alone does not provide immunisation from EI and strict biosecurity measures should be place (Clark, 2019). Following the 2019 EI outbreak in the UK it would be sensible for all equine owners to review their own biosecurity procedures for daily use to prevent the spread of diseases as well as for when outbreaks occur. Whilst the production of a new vaccine is on the horizon, influenza will continue to mutate and the vaccination will need to be reviewed again. The importance of biosecuirty protocols should not be underestimated. Biosecurity should be the primary preventative measure against disease, vaccination production is likely to always be to slow to provide protection against the current strains of EI.
Regarding vaccination alone not being sufficient to immunise against EI, and movement of horses being one of the risks in spreading disease, the Report of the Vaccinology Session of the French Equine Veterinarians Association (Paillot et al, 2016)advocated that in the event of an outbreak of EI an efficient buffer zone should be implemented during emergency vaccination. The vaccine used should be EI with DIVA (Differentiating Infected from Vaccinated Animals)capability. This would allow monitoring of the spread of the disease within the buffer zone and that any animal outside the zone presenting with signs of infection should be considered as a potential EI case.
DeleteIn relation to vaccination safety many years of research go into the development of safe and effective vaccinations. New vaccinations must be assessed by the independent regulator the Veterinary Medicines Directorate. Vaccines intended for animal use must meet specific high standards of efficacy, safety and quality before they are passed for sale and use. As part of the assessment process vaccines must be proven to have greater benefits for the equine population than any expected risk. Once assessed vaccines are monitored for their continued safety and efficacy Vaccinations must be prescribed by a vet as they as classified as POM-V medicines.
ReplyDeleteAlthough the vaccines are rigorously tested and regulated, there is still a chance that they will fail for one or many reasons including, being out of date, exposure to sunlight, death of live vaccine, wrong strainof pathogen and incorrect route of adminitration. (Quinn et al. 2011)
DeleteIn addition to the defects in biosecurity measures, Elder (2019) reports that Dr Richard Newton, director of epidemiology and disease surveillance at the Animal Health Trust, considers the development of anti-vaccine rhetoric on social media to be a contributory factor, as well as confusion “even among vets” as to why there are so many variants between flu vaccine rules between governing bodies. Further supporting Simon’s comments regarding owner sensitisation, Dr Newton goes on to explain the importance of owners routinely monitoring their horse’s temperature, as a rise from the baseline is often the first indicator of many infectious diseases (Elder, 2019). Remarkably, advancements in technology have allowed for the development of the ‘EquiTrace’ app, which works alongside a microchip to record and monitor temperature in a matter of seconds, as well as provide in-depth access to medical records (Elder, 2019; Veterinary Advances, 2018).
ReplyDeleteAnother element to the cause highlighted within the Elder (2019) article is the influence a no deal Brexit may have. Confirmation is needed to ascertain whether the listed status previously granted will apply to the pushed back leave date, as well as the EU’s stance on the recognition of UK breed societies as studbooks. Defra has applied for said recognition, but it had not, as of December 2019, been granted yet.
Continuing on the international policies of vaccination practice, it is evident that the United States follow a similar protocol which includes ‘core’ vaccines and ‘risk-based’ vaccines. (Boehringer Ingelheim, n.d). The American Association of Equine Practitioners (AAEP) recommends all horses should receive the core vaccines, which include vaccinations against West Nile virus, Eastern and Western Sleeping sickness, Tetanus and Rabies (AAEP, n.d; Boehringer Ingelheim, n.d). Whereas risk-based vaccinations include those combating: EIV; EVA; EHV; Anthrax; Botulism; Leptospirosis; Potomac Horse Fever; Rotaviral Diarrhea; Snake Bite; and Strangles (AAEP, n.d).
It should be noted that while the AAEP list EIV vaccinations as risk-based, they also stipulate the Equine Influenza is endemic in the US and as a result, only horses which are kept in a closed and isolated facility are exempt from the recommendation to vaccinate (AAEP, n.d). Additionally, when comparing between the UK and US, US-based Veterinarian Dr Jen Feiner (2016) recommends tetanus vaccines to be administered every 6 months (as opposed to the UK’s every 2 years). Further investigation into the epidemiology of tetanus in the United States as a result of this practice is required.