Bats and Rabies, No. 3

How can Rabies be transmitted from Bats to People?

Dr James Irvine FRSE

The Bat Conservation Trust (BCT) have recently altered information on their website (1) regarding bats and rabies. The changes noted as of 18/12/02 are:

“There is more than one strain of rabies. The “classical” strain associated with terrestrial mammals in Continental Europe - sylvatic rabies - has never been recorded in bats in Europe.”*

* The second sentence of this paragraph, highlighted in red, has now been removed.

“The rabies-related virus sometimes carried by European bats is called “European bat lyssavirus” (EBL). There are two strains: EBL1 and EBL2. In Continental Europe, the recorded incidence of EBL is low. The bat recorded in Bairiki in 1996 carried a little recorded strain known as EBL2. In Europe, EBL2 has been found only ten or so times, in pond bats (which are not found in the UK) and Daubenton’s bats.”

“ Daubenton’s bats rarely live in houses and rarely come into contact with people.”**

** The text "Daubenton’s bats" has now been replaced with "This species".

“European bat lyssavirus (EBL) is transmitted by the bite of an infected bat. There is therefore no risk to people if bats are not approached or handled by them.”

“Bats are not aggressive, although, like any wild animal, they may bite to defend themselves if handled. Most of the UK’s bats have such small teeth that a bite will not break the skin. A bat that appears to be baring its teeth is “scanning” you with its unique echo-location voice, which you cannot hear. More than 1,000 trained voluntary bat workers with the Bat Conservation Trust handle bats regularly for conservation and welfare, with no ill-efects***.”

*** this was changed recently after the death from bat-transmitted rabies of one of their key bat conservation workers, so that the phrase “with no ill-effects” was deleted.

“The treatment of people bitten by bats infected with EBL1 and 2 in the UK and Europe has been completely effective. Nobody who has received the post-exposure treatment has ever contracted rabies.

“The most common bat living in people’s homes, the pipistrelle, has never been found with EBL****.”

**** this was changed recently so that the words “in the UK” were added.

“The treatment of people bitten by bats infected with EBL1 and 2 in the UK and Europe has been completely effective. For example, 180 people bitten by EBL bats in the Netherlands have been treated with 100% success over the past two decades***. Because the risks are so low, public support for bat conservation remains strong, even in countries where some bats carry EBL.”

This section was recently rewritten so that it now reads:

“The treatment of people bitten by bats infected with EBL1 and 2 in the UK and Europe has been completely effective. Nobody who has received the post-exposure treatment has ever contracted rabies.”

As the mission behind the Bat Conservation Trust is to conserve bats and to encourage biodiversity, perhaps it would be wise to check that the rest of the above statements are factually correct and not biased in favour of the good behaviour of bats.

BCT Statement:

“Daubenton’s bats rarely live in houses and rarely come into contact with people.”

Reference to a Scottish Natural Heritage (SNH) Press Release (2), and to the website of the Joint Nature Conservation Committee (3) both indicate that Daubenton's bats frequent “Buildings”. Do these buildings exclude houses? Neither of these websites says so.

BCT Statement:

"The most common bat living in people’s homes, the pipistrelle, has never been found with EBL.”

The fact that the words “in the UK” were subsequently added suggests that EBL has been found elsewhere in pipistrelle bats. This in turn implies that the infection of bats by EBL virus is not so species specific as the BCT previously stated. Indeed this suggests that other species of bats may well be susceptible to acquiring EBL virus if the circumstances are right.

As discussed in Report No 2 of this series (4) there is evidence in the States that the incidence of EBL in bats is quite markedly increasing. Although the USA has a different range of species of bat there was no mention in the Centers for Disease Control and Prevention (USA) report (5) that any one species of bat was more susceptible than another. According to the USA experience, rabies-related virus may affect any of the 39 species of bat in the USA. That being so, it is wrong to suggest that in the UK or Continental Europe that only certain species of bat may be affected and the other species are necessarily exempt from being infected with such viruses.

BCT Statement:

“The treatment of people bitten by bats infected with EBL1 and 2 in the UK and Europe has been completely effective. For example, 180 people bitten by EBL bats in the Netherlands have been treated with 100% success over the past two decades. Because the risks are so low, public support for bat conservation remains strong, even in countries where some bats carry EBL.”

The recent deletion of the sentence, highlighted in red, from the above paragraph suggests that the BCT did not want readers to know that so many people in the Netherlands had been bitten by EBL infected bats, or that the figures were now even more dramatic. It would appear that the information has been suppressed.

BCT Statement:

“The treatment of people bitten by bats infected with EBL1 and 2 in the UK and Europe has been completely effective. Nobody who has received the post-exposure treatment has ever contracted rabies.”

Sadly, the first sentence of this section is manifestly not true on account of the death from rabies of one of their own key bat conservation workers. True, he did not agree to be vaccinated after exposure. Indeed, although he was working intensively with bats, he had not accepted the standard advice that he should have been prophylactically vaccinated, and no one had enforced it when he was working under license from SNH. Once clinical symptoms of rabies appear, there is no treatment available and death is inevitable. BCT should have made that clear on their website and leaflets. The BCT should also have made it clear that the treatment of people infected with rabies-related virus in countries other than UK and Europe has not been effective when the person was unaware that they had been bitten by a bat. The inference made by the BCT that persons would necessarily know if they had been bitten by bat is seriously false.

SNH issued a second Press Release on 20/11/02 (6) stating that they had withdrawn the licenses for the majority of volunteer and contracted bat workers, whether vaccinated or not, until further notice, pending a precautionary review of procedures. It stated that until further notice, the only people to handle wild bats in Scotland will be in a small SNH-led team. The notice claims that experts who have been vaccinated have been identified around the country, in order that any situations arising which require wild bats to be handled can be met.

Land-Care previously understood that the Bat Conservation Trust was responsible for organising the bat conservation workers throughout the UK (under license from SNH). SNH now says it is going to do this for Scotland. An out of office hours telephone number is given. However, most persons would find difficulty in being aware of this as the SNH website still does not respond to inserting the word "bats", let alone the word "rabies", into its own web search facility. One wonders what experience SNH actually has in organising bat conservation workers. One also has to wonder why a fatality was apparently required to shake them out of complacency regarding the dangers of rabies in bats that had been so well documented by the National Center for Infectious Diseases in the USA (see below). After all, in farming one can hardly move without some certification of competence which is applied to many kinds of agricultural activity, under severe threat of penalties. Can SNH not keep its own house in order?

The bland reassurance from the Chief Scientist of SNH which states: “Given that bats are currently in hibernation, there should be no great need for anyone in Scotland to be handling wild bats anyway”. This website understands from persons whose houses are occupied by bats, that they do not hibernate as conscientiously as the Professor says they should. The Professor states in this SNH Press Release: “It all comes down to avoiding direct contact with any bat”. Unfortunately, as detailed in the next section of this article, that is not so easy if a person’s house is occupied by bats that are not hibernating quite as they should. But then neither SNH nor BCT wish to face up to the potential dangers to the public when bats do occupy houses (a common occurrence). That would interfere with their blind adherence to a policy promoting the dogma of conservation and biodiveristy.

Do People always know that they have had Significant Contact with a Bat?

According to the Centers for Disease Control and Prevention (7) and the National Center for Infectious Diseases (8) in the USA, people do not necessarily know that they have had significant contact with a bat, or indeed any bat contact at all - and yet they can die of untreatable bat-transmitted rabies. This is shown in Table 1 (Click here to view).

This observation is also reflected in the advice given out by the National Parks Service of the USA (Click here to view).

The National Center for Infectious Diseases website (8) gives a list of the twelve commonly asked questions and their answers concerning human rabies and its prevention. Question 4 and the answer to it is reproduced here. It stresses that "postexposure prophylaxis should be considered when direct contact between a person and a bat might have occurred, unless the person can be certain a bite, scratch, or mucous membrane exposure did not occur". A bat entering the room of a sleeping person is an example of a situation where this might be the case.

The case histories of the last 10 cases in the USA who developed rabies are shown here. A bat with rabies may not behave normally, as demonstrated by two of these cases. Victims in Minnesota, 2000, and in Texas, 1997, both awoke to find a bat had landed on them. It is therefore misleading to state that bats will necessarily keep out of the way. That may be the case for healthy bats, but not for bats infected with rabies-related virus/es. When a bat contracts rabies, it becomes lethargic and dies. This is unlike the aggressive behavior of some other mammals (9).

A Case Study of a girl who died of rabies transmitted from a bat is shown here reproduced from Centers for Disease Control and Prevention (USA) website. Although there was a bat in her room, there was no evidence that she had been bitten by it. The Centers for Disease Control and Prevention (USA) website provides advice on how to capture bats that have entered your home. This information has been reproduced here. It has been noted that, in the UK, the helpline for assistance in removing bats from the home is only available during office hours.

It will be clear from the above evidence (all documented authoritatively by the Centers for Disease Control and Prevention in the USA), that the implied assurances given out by BCT, that there is no problem unless the subject knows that he/she has been bitten by a bat, are incorrect. The American experience documented above states unequivocally that a person may be infected with rabies without knowing it. Proof that the source of the rabies-transmitting virus was a bat can be established by analysing the structure of the virus involved, as described in some of the cases included in Table 1, and the case histories of the last 10 rabies cases in the USA (Click here to view).

Bland reassurances that people living in houses which are also occupied by bats, have no need to fear getting rabies from these bats, cannot be substantiated. They do stand a small but significant risk of becoming infected with rabies virus. The tragedy is that, by the time they show symptoms it is too late to be able to cure it and death is inevitable. The advice the American authorities give is to catch the bat (wearing heavy gloves etc) and to block up the rooms in the house where a bat is likely to be.

Reference to the SNH website, and using the search facility for the words bats and rabies provided no information. On contacting SNH by telephone (using the number given on heir news release - which has since disappeared from their website) the caller was referred to the websites of the Bat Conservation Trust and of the Joint Nature Conservation Committee. This seemed a little odd, since SNH holds the licencing authority for all persons working with bats in Scotland. Perhaps they might have had some reference to bats on their website, rather than so much self advertising/promotional material.

Summary

There is evidence from the USA that the incidence of rabies-related viruses in bats is increasing (see No 2 in this series of articles). It is quite possible that this may be happening in the UK and Continental Europe.

There is no justification for inferring that rabies-related viruses are only likely to occur in certain species of bat. With such a strict bat conservation order on all species of bat in the UK, it is probable that the spread of rabies virus in bats from Continental Europe and further afield is being encouraged.

There is no justification for the false assurance that rabies infected bats will necessarily behave normally i.e. keeping out of the way and not being aggressive. Experience in the USA shows that rabies-infected bats may behave quite abnormally and that there may be a significantly greater risk of being bitten by a rabies infected bat compared to a healthy one, and that the victim may be unaware of it.

Consequently, bland assurances put out by the Bat Conservation Trust (BCT) that people have nothing to worry about if they have bats in their houses are seriously unfounded and misleading.

In view of the above evidence (which has been widely available on the internet for a period of years for anyone with a desire to seek it from highly authoritative and independent sources) is only now being brought to the attention of the unsuspecting public.

It is a matter of great concern that the Bat Conservation Trust and Scottish Natural Heritage (among others) have apparently deliberately mislead the public to further their own unifocal creed of increasing biodiversity at the expense of the welfare of the public who fund them.

References

1. Factsheet: Bats and Rabies. The Bat Conservation Trust.
(http://www.bats.org.uk/batinfo/rabies.htm).

2. SNH Press Release, 20 November 2002. Suspected Case of Rabies in Tayside. (Click here to view).

3. Website of the Joint Nature Conservation Committee (http://www.jncc.gov.uk).

4. Irvine, W. J. (2002). Bats and Rabies, No. 2: Comment on letter from Bat Conservation Trust, Courier 30 November 2002. The prevalence of European Bat Lyssavirus (EBL) in the UK. Land-Care (Click here to view).

5. Centers for Disease Control and Prevention (USA). (http://www.cdc.gov).

6. SNH Press Release, 20 November 2002. Bats. (Click here to view).

7. Bats and Rabies. National Center for Infectious Diseases. Centers for Disease Control and Prevention (USA) (http://www.cdc.gov/ncidod/dvrd/rabies/bats_&_rabies/bats&.htm).

8. Twelve Common Questions About Human Rabies and Its Prevention. National Center for Infectious Diseases. Centers for Disease Control and Prevention (USA) (Download [pdf]).

9. National Parks Service (http://www.nps.gov/wica/Bats.htm).

Key Websites

Centers for Disease Control and Prevention (USA) - http://www.cdc.gov/
Joint Nature Conservation Committee - http://www.jncc.gov.uk/
National Park Service - http://www.nps.gov/
National Center for Infectious Diseases - http://www.cdc.gov/ncidod/index.htm
Scottish Natural Heritage - http://www.snh.org.uk/
The Bat Conservation Trust - http://www.bats.org.uk

Land-Care Search

If you would like to search Land-Care please click on the word "Search" located at the top right of every page. Be sure to click the button next to "Search land-care.org.uk" before searching.

MENU

18 December 2002

Bats and Rabies, No. 3

How can Rabies be transmitted from Bats to People?

Dr James Irvine FRSE

BCT Statement:

BCT Statement:

BCT Statement:

BCT Statement:

Do People always know that they have had Significant Contact with a Bat?

Summary

References

Key Websites

Other Land-Care articles on bats and rabies

Land-Care Search