What don’t you understand about snorting horses, Mr. Vet?
Lee St.John Carter B.Sc. [zool.] Dip.Ed.
The first draft of this discussion paper has already generated critical comment that I have embraced in this draft and I thank the correspondents. I do intend it to be provocative and critical as well as analytical, informative and questioning.
The title comes from viewing a TV news item at the time of the Redlands Veterinary Clinic Hendra virus incident. A man from biosecurity was interviewed and made some speculative and highly improbable comments on the transmission of Hendra virus. The news piece then cut to a horse in a yard, which promptly came over and snorted at the camera! From my point of view, the most relevant ‘comment’ so far!
Information currently available on DPI&F and Queensland health websites is not very helpful [indeed, maybe misleading], in understanding, preventing or appropriately responding to another incident. I am concerned that the next victim might be a horse handler, not a vet. If you consider my hypothesis, the probability that the next event involves a child’s pet horse in a suburban backyard is higher than any other scenario. Nothing that has been learned about Hendra virus and, in particular, no information currently available to the horse owners’ community can mitigate the potential for further fatalities this scenario could produce. The R.V.C. incident only supports my concerns.
My personal involvement started from the perspective of a flying fox researcher initially concerned by suggestions of the possibility of Hendra virus infection during close encounters with megabat colonies. While attempting to survey a very large flying fox camp in company with two N.P.&W.rangers, we were exposed to a shower of ‘body products ’while negotiating a difficult traverse in dense rainforest regrowth within the colony. This event occurred just prior to receiving advice from the E.P.A.[16 July 2008] that “…IF ANYONE COMES INTO CONTACT WITH A FLYING-FOX OR ANY OF THEIR BODILY FLUIDS — report this immediately to Sue Johnston, Population Health Officer….”and also advice that observers should not be closely approaching colonies for fear of Hendra virus infection.
As well as this event, here, in Hervey Bay, we have a breeding colony of Black and some Grey Headed Flying Foxes. They have a traditional camp in a small isolated mangrove swamp and costal woodland area. This area is in a recreation reserve on Tuan Tuan Creek, adjacent to the esplanade in the centre of the city. Larger numbers of Grey Headed Flying Foxes and Little Red Flying Foxes seasonally visit the camp and, in drought years, or following extreme weather events in the north, the numbers of animals in the colony reaches the millions. Although they are a tourist attraction and the colony has its protectors, as well as legislative protection, there have been various attempts to move or disperse the colony. Concerted dispersal attempts in the past have led to the colony roosting in high trees in the nearby caravan park on the esplanade, which was rather less desirable than leaving them alone in the swamp! However, they have been persistently disturbed and three years ago many of the adult females chose to roost and birth in the tall trees overhanging the bike and pedestrian walkway on the esplanade adjacent to the colony area. Here, they were subjected to fewer disturbances than in the colony area!
Fortunately, Flying Foxes do not behave like seabirds, which deliberately defecate on persons passing under their nests! Having black bodies and hanging in the sun, their metabolism is engaged in water conservation strategies so there are no showers of urine![they possibly urinate on themselves to produce evaporative cooling when it is very hot] Also, there has been no evidence of placentas or other birthing products raining down on the bike path, although I have been present on birthing days! Negative publicity continues to be generated by the bat-hating brigade at any opportunity and the recent Hendra virus events provided them with “evidence” to feed this negativity.
After the association of Hendra virus with flying foxes became apparent after the first outbreak in 1994, I formulated a hypothesis about the mode of transmission, based on the behaviour of flying foxes and horses. The more recent events have only reinforced my hypothesis.
I have become increasingly concerned by recent events including a catalyst program on the Hendra virus and the possible dangers to human health posed by this bat born virus, and a recently released report titled “ Independent review of Hendra Virus cases at Redlands and Proserpine In July and August 2008 ”. This review, and other Hendra virus information on Queensland Health and D.P.I&F web sites, which I have recently reviewed, have led me to conclude that bureaucrats [biosecurity?] responsible for managing Hendra virus outbreaks have failed to understand the critical issues [which includes what we do now know about Hendra virus and conclusions based on that knowledge] and have proceeded and continued with inappropriate policies, legislation, and actions. This has led to more fatal outcomes, and is likely to lead to events with further predictable fatalities of persons handling horses as well as transmission between horses, particularly in stables, and resulting multiple mortalities of horses.
I am presenting the hypothesis that I have formulated, which still fits all the information I have reviewed so far. I also comment on some implications of my conclusions for both vets and horse owners and briefly comment on some of the published documentation and legislation, and my concerns about their relevance to the current situation.
The Hendra Virus Transmission Scenario
Hendra Virus is a common endemic virus in flying foxes, yet it is extremely hard to transmit, suggesting that it is essentially a S.T.D. in flying foxes. It could be transmitted through the adults who are polygamous and engage in vulval licking [probably to detect hormones in urine or secretions] during the mating season in autumn, and to the young, congenitally, during the birthing season that is in spring [six months apart]. Either of these possible transmission routes would characterise Hendra virus as an S.T.D. If the transmission route were less ‘intimate’, then Hendra virus would be more infective than it apparently is. Of course the possibility of slightly less intimate transmission can not presently be ruled out, because Flying Foxes in the camps have a ‘personal space that is less than a wingspan, even between species, and far closer within each species. Flying Foxes have a very well developed olfactory system and transmission could be similar to the route between horses.
Although only producing subclinical symptoms during experimental infections, the virus is apparently present in some body products during its infective stage. Presumably the virus would be most active [and transmittable] following the mating and birthing season, and when the animals are otherwise stressed [for example, during winter food shortages]
The behaviour of megabats, particularly in the camps, which always contain whichever of the 4 species is present in the area, is critical to an understanding of how these highly intelligent flying, primate like, mammals manage to survive the inevitable challenges to their health that living in large multispecific colonies provide. Their migratory behaviour both adds complications but also suggests answers, particularly with regard to external parasite loads.
While Little Red Flying Foxes and Grey Headed Flying Foxes are primarily nectar eaters and migrate to follow the blossom seasons of winter flowering hardwoods and other trees, Black Flying Foxes do not migrate to follow the blossom fields. They rely on local blossom and fruits. They are more urban animals with a more frugivorous diet. In the absence of flowering trees or soft fruits they consume more fibrous fruits including unripe fruits [all flying foxes do this when food is scarce!]. Flying Foxes often carry fruit away from fruiting trees to process and consume in temporary roost trees. They process this high fibre, low energy food by chewing the fruit to a pulp, presumably adding saliva, then squeezing the pulp between tongue and palate to separate the juices that contain carbohydrates and sugars from the pulp. The juices are then swallowed and the pulp is then spat out along with any large seeds. A friend recently observed a ‘bat splat’ as he described it, with three Cocos palm seeds in it. Cocos palms fruit in winter and are a preferred food of Flying Foxes in suburban environments. Cocos palm fruit are one prime suspect in my transmission scenario!
It is these ‘bat splats’ that are actually attractive to the highly developed sense of smell of a horse. Horses, along with most herbivores, have a negative response to faecal matter, evolving from the very real likelihood of parasite transfer. “Bat splats” smell like a fruity morsel. They are not excretory matter! Interaction between horses and ‘bat splats’ is probably quite a common occurrence. Cocos palm seeds may even be chewed before ingestion. The probability that a particular ‘splat’ is actually infective is quite low and the probability that infection is actually transmitted during an interaction is also low. With an average of one or two incidents of transmission every few years, the transmission scenario is obviously uncommon but predictable.
In the past I have been quite amused by the amount of food [such as chaff] that ends up in a horses nostrils when it is feeding. Horses don’t just sniff at their food, they also snort [exhaling forcefully], propelling food particles into the air and then sniff it up their nose. Snorting a fresh “bat splat” from an infective flying fox is the only likely mode of transmission of Hendra virus to horses. Virus transmission via a “bat splat” could occur through infected saliva, nasal mucus or epithelial cells in the splat.
It is the horses’ tendency to snort that is also the most likely mode of transmission of the virus from horses to other horses, as well as to humans. Snorting horses spray the [infective] mucus from their noses. Small droplet generation is the most effective way to dispense and enhance the effectiveness of insecticides as well as infective agents used in biological warfare and is the most common viral transmission mode [e.g. sneezing transmission of flu and colds] People handling horses do so, face to face. A snorting infected horse is a close range, biological weapon grade virus dispenser [And not so close range dispenser of more infective viruses like horse influenza!?] Transmission is most likely when handling sick horses and, particularly in the close confines of stables, between horses. The modes of transmission from bats to horses, postulated in the literature, vary from highly improbable [faecal or urine contamination of food] to ridiculous [contamination through birthing products!]. This is a deductive hypothesis and it is worth noting that looking for evidence of this transmission after a Hendra incident is a complete waste of time and resources since the event is separated by time. The event scene is no longer a transmission scene with any relevant evidence present!
Conclusions, from an understanding of the scenario, for vets
When my doctor or my dentist examines me, they wear a surgical mask and gloves for mutual protection from various infections. Horses with Hendra virus may be infectious before they show gross symptoms. The wearing of P.P.E. respirators after diagnosis with Hendra virus is too late and probably completely unnecessary as are the current protocols for handling and disposal of dead horses. I am extremely disturbed by the assertion in the Web document titled “ Handling possible and probable Hendra virus cases in equines -Guidelines for veterinarians including procedures for handling cases” which states in a note [5] “A standard surgical facemask is not a respirator and will not provide respiratory protection. (Refer to Australian Standard AS 1715 for information on implementing a respiratory protection program).” This assertion is based in fear alone, when applied to the real world of horse human interactions and contradicts long standing medical practice. Does Queensland Health follow these guidelines when treating human victims? It is certainly true that aerosolizing procedures during post mortem demand higher levels of respiratory and eye protection. This is a health issue for vets, and also medical examiners doing human postmortems. [Do doctors follow similar guidelines during postmortems?] Fatalities’ arising from inappropriate hygiene standards of vets during postmortem or other invasive procedures has nothing to do with preventing, mitigating, treating or generally managing actual Hendra virus events!
For me, it is quite simple, vets should be wearing surgical masks and not just when examining sick horses. A sick vet could transmit swine flu back to a pig with potentially far more consequences to the communities’ health![In fact, since the first draft of this paper, this has occurred, apparently via a farm worker not the vet! I wonder if biosecurity were at all proactive, once we had the first cases in the human population? Was the pig industry warned of the likelihood of zoonotic transfer back to the pigs?] In the case of Hendra virus, only the vet or horse handler is in danger, with other zoonotic diseases, the possible consequences are more far reaching!
Wear a surgical mask, apply the same hygiene standards as medical personnel, or risk a fatal infection or other zoonotic transmission.
Conclusions for persons associating with horses,
If you understand the above scenario then you should be also wearing some protection from a possibly infected horse. Contrary to the assertions of D.P.I&F that P.P.E respirators are necessary to protect from Hendra virus infection, the reality is that the chances of infection while handling horses, in the quite uncommon scenario of an actual Hendra virus infection, would probably be reduced by an order of magnitude [from around 40%?] to practically zero simply by wearing a cloth scarf or bandana over your mouth and nose as an initial precaution against getting ‘snotted’ when handling a sick horse [personal hygiene like washing your hands is also appropriate]. Certainly a surgical mask would be a good investment and you could use it in the flu season! It has been suggested that a clear facemask could be useful for horse handlers, as it would also provide protection from infective particles entering the eyes, which could be an alternative infection route.
Obviously any horse suspected of having Hendra virus needs to be isolated from humans and other horses. Currently there is no treatment that can help the horse to recover, since there is no antiserum with the necessary antibodies to fight the infection available. This is because the horses that could have supplied it, the ones that survived an infection, were all euthanased!
Horses with Hendra virus, when left alone, either die fairly quickly, or recover [more slowly].
At the present time, if a vet receives a conformation of Hendra virus and your horse survives the infection, the vet is legally obliged to notify D.P.I&F. who currently have a compulsory euthanasia policy!?[See my comments below on this policy]
Initial advice on Hendra virus tended to minimize the danger of stabled horses contracting the virus. The reality is, that if a horse brings Hendra virus into a stable environment, because it is a closed space, the likelihood of air born droplet transmission is greatly increased. Because we are talking about snorting horses, if they are working horses, the probability of transmission is further increased. Considering the behavior of horses and the dangers from the transmission of various diseases, it seems obvious that current designs for housing horses are seriously flawed from an animal health perspective. At the very least, clothe screens between stalls could seriously reduce the probability of air born droplet transmission. Quarantine of the premises does nothing to prevent the spread of infection between horses in the premises! It is time someone invented a nosebag ‘surgical mask for horses’. It would be a lot cheaper than canceling a significant equestrian event to slip a mask on every horse in the event of, for example, a suspected equine influenza outbreak, in the case of a stable with a suspected Hendra virus case it’s a no brainer!
General comments from my review, and questions for researchers
The first problem that I perceive is the references to outbreaks of Hendra virus and its relationship to threats of newly emerging, potentially epidemic, zoonotic diseases. Hendra virus is not potentially epidemic, nor is it exotic, or even newly emerging. Hendra virus incidents need to be understood as relatively uncommon, but quite predictable, natural occurrences [They will keep occurring!] These incidents need to be placed in proper perspective and managed accordingly. Hendra virus is a potentially lethal infection in horses and man. Occurrences need to be managed as serious health events. There is no evidence that they need to be treated as potential epidemic outbreaks by a team of biosecurity personnel. There is the obvious necessity of identifying and isolating of possibly infected horses prior to treatment. This isolation does not have to be a PC4 containment facility just an isolated stall or a double fenced yard [and a sign, Do not pet the sick horse! etc.]
“A decision was made to order the destruction of the horse under the legislative authority of the Exotic Diseases in Animals Act (1981).” The problem with the Exotic Diseases in Animals Act (1981) is that it is now flawed legislation, inappropriately altered for bureaucratic convenience. One flaw is, that ‘exotic diseases’ are defined as the diseases that are on the list of exotic diseases in the act. Circular definitions have unexpected outcomes!
This list originally contained several serious exotic epidemic diseases of livestock with serious economic consequences from an outbreak here in Australia. This act was designed to provide powers to assist in eradicating such an outbreak. The inclusions of both Hendra and Bat Lyssa virus on the list is completely inappropriate since they are neither exotic or epidemic [and therefore can not be eradicated!], and have no serious economic implications for livestock [other than being euthanased if antibody positive!] Also, the Flying Foxes that are their natural hosts are protected; ecologically important native species and there is no way that the powers invoked under this act are going to be used against them. If the contemplated strategy of persons in biosecurity is a destruction strategy involving Flying Foxes then this needs to be completely denounced and dispatched to the great rubbish bin of really bad ideas…
Hendra virus is not an exotic disease, it is a common endemic disease of flying foxes with the demonstrated ability for an uncommon, limited, but predictable transmission to horses and very limited predictable ability for further transmission to humans and horses .The decision to euthanase horses that survive a Hendra virus infection may have had an original logic in the containment of an apparent outbreak of a serious zoonotic, but since the limited transmissibility of the virus became apparent, and the natural host was identified, that argument has no merit or relevance.
There has been reference to the possibility of the re-emergence of the virus in these horses leading them to again become infective. This is very unusual in any virus diseases when an appropriate antibody response has manifested. There is no evidence of this in horses, and there never will be, if horses that survive continue to be euthanased! The references of re-emergence, refer to human infections of the related Nipah virus, which could be of concern to the human survivors of Hendra virus, but is hardly relevant to horse infections. This act has been compromised by its amendments.
The Exotic Diseases in Animals Act (1981) is not the only flawed document that has been used by biosecurity personnel. The R.V.C. Hendra virus review document refers to the Ausvet plan as follows-
“ The AUSVETPLAN brief policy statement for Hendra virus infection is reproduced here.
Australia’s policy for Hendra virus infection
Hendra virus infection is not an OIE-listed disease. The disease has proven to be only mildly contagious outside its natural hosts. Relapse and serious infection in clinically recovered or partially recovered horses can occur.
The policy is to eradicate Hendra virus infection in terrestrial animals using:
destruction and sanitary disposal of all horses or other terrestrial animals shown, through demonstration of antibodies, to be infected;
disinfection of the immediate contaminated environment; and
quarantine of all in-contact animals until repeated serological tests have proven freedom ”
This ‘policy’ for Hendra virus is internally contradictory, unethical, Inhibits actual research towards successful treatments, causes vets to violate their duty of care to both their clients and their animals, has an impossible aim, implies the destruction of a protected native animal to achieve that aim and in reality, does nothing to achieve any result at all! It certainly has made no difference to the outcomes of any of the incidents so far. In fact, when the horse owners’ community becomes aware of this plan and its implications, there will be an understandable reluctance to involve any vets or DPI&F biosecurity in any suspected Hendra incident.
This brief policy statement obviously has its origins in the document titled:
AUSTRALIAN VETERINARY EMERGENCY PLAN
AUSVETPLAN
1996
Operational Procedures Manual
Destruction
This is a document about how to kill animals [humanely?] in case of an epidemic outbreak, in order to contain that outbreak. Rather more sinister is a reference to the “ Wild Animal Control Manual, in press.” It does not say feral animal control and it seems if destruction of bats or other native animals is suggested in this document? These acts and policies are inappropriate for dealing with Hendra virus [or any other endemic virus] in any meaningful way. They have produced a fatally flawed response with no positive outcomes.
This ‘Policy’ plan for Hendra virus needs to be thrown into the rubbish bin. Hendra and Lyssa virus both need to be removed from the list of exotic diseases in the “Exotic Diseases in Animals Act (1981)” with all its nasty and unhelpful implications. The following extracts from that legislation are quite disturbing in their implications for horses and flying foxes.
Division 6 Powers of inspectors
20 General powers of inspectors
(e) may destroy any animal which is or which the inspector suspects on reasonable grounds to be infected with rabies;
(h) may search for, bait, trap or destroy vectors of exotic disease;
Example of destroying a vector of exotic disease—
killing the vector by poisoning it
(p) may order an owner to—
(vii) hunt and destroy undomesticated animals specified in the order and for the purposes of such hunting and destruction the provisions of the Nature Conservation Act 1992 shall be deemed not to
apply;
Have all the natural victims of Hendra virus been compensated under this act? The act clearly states that:
“ 29 Compensation
Subject to this part, compensation shall be paid to the owner
of— (b) any animal which is certified by a government veterinary officer as having died during the period of the outbreak notified pursuant to section 28 of the exotic disease specified in the notification and which at thetime of its death was situated in the area of the State notified in respect of that disease.”
Compensation will still need to be paid even if the act has been inappropriately amended and invoked, and is corrected, because the obsession with implementation of the plan with its destruction policy, has resulted in no appropriate treatment response but, in fact, has inhibited [actually prohibited!] the development of suitable medication or other treatment.
One important question that has not been answered by current reported studies, is how long after death, viable virus remains in a dead horse, its secretions, or on surfaces where it has been deposited? [And similarly for bat secretions!] Unlike bacteria or fungi, where viable organisms remain for long periods, viruses generally need living tissue to remain viable. The cooling to ambient temperature and cell lysis should render the carcass non infective unless this virus has the unusual ability to persist in the environment outside a host!? The infectivity of air borne droplets or small particles containing the virus would appear to be measured in seconds, not long periods [If this virus was anywhere near as viable outside the body as swine flu, we would already have a lethal epidemic!] It would appear that most disinfection and safe handling protocols by persons in white biohazard suits are unnecessary and only create the illusion that something is being done.
One document on the equine influenza virus refers to this virus being “excreted into the air” which is just rubbish terminology. Unfortunately this leads to the conclusion that molecule size, viable virus particles might be present in the atmosphere. This type of misunderstanding, of modes of transmission, would appear to explain the assertion that P.P.E. respirators are necessary for protection from Hendra virus infection. Using terminology such as “the shedding of the virus” is also unhelpful in understanding viral transmission. If you use the term ‘infective’ then it leads to reasonable, verifiable questions on possible transmission modes!
It can be predicted from the current statistics that there may be a very small number of antibody positive horses out there and it needs to be acknowledged that these horses represent no threat, and, even if re emergence was possible, the threat would be no different to that provided by a new event!
In Queensland registration of horses is compulsory. Horse owners’ [and Flying Fox conservationists] should be disturbed by current activities and legislated powers. In the context of Hendra virus [antibody positive] testing, the concurrent, compulsory euthanasia, policy and the inclusion in the list of exotic diseases in the ‘exotic diseases in animals act’, this is an unproductive, overbearing, costly, abuse of legislative powers, and a bureaucratic mess!
How should we be responding to this undeniably dangerous virus? Define the actual infective potential of the virus. Start testing ‘bat splats’! Develop an antiserum for the one or two cases that may occur annually. Educate vets regarding veterinary hygiene. Alert and educate the horse handling community to productive safe handling strategies for sick horses. Realise that this is a natural phenomena and actual transmission events cannot be avoided any more than snake bite or a puncture wound leading to tetanus. Listen to Flying Fox researchers and ask them the right questions. Put power tripping, bureaucratic bastards, with tunnel vision and their inappropriate invoking and manipulating of legislative powers, on notice to be named and shamed!
There are many other issues and criticisms that arise from the current state of affairs concerning Hendra virus and its management. There is one disturbing conclusion that I have reached, and that is, nothing that has been done or recommended by biosecurity personnel, has saved a single horse or human, or is likely to in the next event!
My transmission hypothesis is testable and potentially a lot more helpful in understanding and managing Hendra virus occurrences [and perhaps Nipah virus outbreaks?], than some current activities [like euthanasia for horses or any other animal, or collecting urine samples from around bat colonies!].
I hope informed researchers and government bureaucrats come to conclusions leading to more appropriate responses, policies and research in the future. I am very interested in getting feedback, criticism, editorial correction etc., on this paper and the issues it rases [and also any relevant research papers or information]. It can be copied [in full] and passed on to interested persons for consideration.
Lee St.John Carter 77 Wheeley Road, Booral, Hervey Bay 4655. Tel.07 41257127.
P.O. Box 5011, Torquay, Hervey Bay 4655
batwatcher1@hotmail.com
First draft-produced 22 June 2009.
Second draft-produced 14 August 2009
Disclaimer…Disclaimers are refuges for the ignorant and incompetent.
P.S. I have researched and produced this document as a private researcher and concerned citizen, I have received no funding or support. If a government department employed me, part of the conditions of employment would be various constraints on my voicing my opinions. I have spent considerable time reviewing this issue. If you support my efforts, don’t send thanks. Send money!
