Since BSE first appeared in England in the late eighties, the Israeli veterinary Services (IVSAH) follows the developments outside Israel routinely, and reacts accordingly.

No cases of BSE have yet been diagnosed in Israel. The risk of an outbreak of the disease in Israel depends mainly on the:

(a) probabilities that the causative agent of the disease (the prion?) entered the country through infected live cattle or contaminated cattle meat and bone meal, MBM (the “external threat”); and

(b) the infected material being recycled (rendered) and introduced into the feed chain of the local cattle (the “internal risk”).

The External Threat

The external threat is the outcome of the probabilities that BSE actually entered the country through live cattle or MBM and the amounts imported since the late eighties.

Import of Live Animals into Israel

Live cattle have not been imported from GB since 1974. Import from all other countries, since 1992, was allowed only from herds, which had not been fed with MBMs, and - if from countries known to be infected with BSE (e.g. France) - only from areas free of BSE. The imports since 1980 are described in the Table 1.

Table 1:
 

Year	Country	Amount	Purpose (all beef)
1980	“Europe”	90	Bull calves for breeding
1981	“Europe”	115	Bull calves for breeding
1982	No import
1983	France	93	Bull calves for breeding
1984	France	114	Bull calves for breeding
1985	France	104	Bull calves for breeding
1986	France, Germany, Germany	130, 11, 500	Bull & female calves, heifers for breeding
1987	France, France, Germany	156, 68, 725	Bull & female calves, heifers for breeding
1988	France	67	Bull calves for breeding
1989	France	55	Bull calves for breeding
1990	France	55	Bull calves for breeding
1991	No import
1992	France	262	Bull calves for breeding
1993	France, Germany	886, 94	Fattening, heifers for breeding
1994	Germany, France & Germany	70, 231	Fattening, bull calves for breeding
1995	France & Germany, France	68, 394, 150	Bull calves for breeding, slaughtering*
1996	France	50, 63	Heifers, bull calves for breeding
1997	France	87	Bull calves for breeding
1998	France	110, 570	Bull calves for breeding, slaughtering*
1999	France	62	Bull calves for breeding
2000	Germany	132	Bull calves for breeding

* All bull calves for slaughtering were under the age of 18 months, slaughtered within 8 days of arrival to Israel.

Import of MBM into Israel

The import of MBM of mammalian origin from the UK and from all other countries was prohibited in 1988 and 1990 respectively. The import of poultry MBM was permitted only from plants authorised by the local veterinary authorities. The purpose of the authorisation was to ensure that the MBM is produced in the plant specifically allocated for poultry MBM, and follows the specified requirements set out by the IVSAH.

The imported MBMs have been tested since 1996 against mammalian antigens to ensure that the protein does not come from mammalian sources. It came to our notice only recently that mammalian antigens are destroyed in the process of rendering that involves heat treatment above 121^oC. Prions, the agents possibly responsible for BSE, are only destroyed at 133^oC. The test used could not therefore have guaranteed that imported “poultry” MBMs do not contain mammalians’ proteins. Shipments from GB (the most risky source) are accompanied by MAFF’s labs’ certificates based on tests, which diagnose mammalian antigens even after heating to 140^oC for 90 minutes. The import of MBM (in tons),from all animal species, in the relevant period from European countries is described in the Tables 2:

Table 2:
 

	United Kingdom		France		Holland		Denmark
Year	Poultry By- Product	Feather Meal	Poultry By- Product	Feather Meal	Poultry By- Product	Feather Meal	Poultry By- Product	Feather Meal	Fish Meal
1986			40*						1730
1987									1680
1988	17		20*		597*	22			1092
1989	3844	29				343	3947*		489
1990	3590	1629	**40	399	**1470	1419	**1076		461
1991	8937	3726	173	1028					244
1992	7928	4482	165	409		91	***2594		223
1993	8164	6423	328	1031		93	1157		82
1994	2064	3131	598	2048	294	1015	898	21	167
1995	2002	3096	305	840		766	180		175
1996	443	1288
1997	3247	881	485	1593	145	1940			177
1998	5258	1334	541	956		619			1311
1999	6137	339	337	535		405			125
2000	1111	623	430			850			117

  

	Belgium		Germany		Italy		Spain
Year	Poultry By- Product	Feather Meal	Poultry By- Product	Feather Meal	Poultry By- Product	Feather Meal	Poultry By- Product	Feather Meal	Fish Meal
1986	810*				1200*		1450*	790
1987	1150*	10	1771*		1000*		1752*	47
1988	802*		1053*		6737*		2808*	1298
1989	1100*	5	6374*	264	1820*		2929*	2410
1990	1220**	5	2688**	470	300**		1110**	689
1991			343		3548	98	316	191
1992			507		3872	304			75
1993
1994					3572	55
1995					1866
1996
1997			55		18
1998			110
1999
2000			****23

*Poultry by-product might have included mammalian MBM before 1989.

** A total ban on all mammalian MBM was imposed in 07/1990.

*** Porcine MBM (from a plant dealing exclusively with pig material).

**** Poultry blood meal.

The external threat, if exists, could be summed up in the penetration of unknown quantities of BSE agents in into Israel, through MBM exported as “poultry MBM”, if in spite of the certification of the veterinary authorities in the exporting countries, the poultry MBMs were contaminated to various degrees with mammalian MBMs (and therefore possibly with the BSE agents). A complete fraud (selling cattle MBM as poultry one) is practically impossible because of the different contents of mammalian MBMs, poultry MBMs and feathers’ meals, which are obviously checked by the importing feed mixtures manufacturers (Table 3):

Table 3:
 

	Ruminant meals		Poultry Meals
	Meat	Meat & Bone	Feather	By-Product
Crude Protein (%)	55.0	50.0	80.0	60.0
Crude Fat (%)	10.0	10.0	6.0	12.0
Crude Ash (%)	15.0	28.8	2.8	15.5
Calcium (%)	8.5	10.1	0.3	3.0
Phosphorus (%)	3.5	5.0	0.6	1.7

The risk of introduction of the disease through the imported bulls could be estimated as negligible.

The Internal Threat or the System Stability

Since 1996, Israel prohibits by law (and in practice) recycling of mammals. Recycling of poultry is allowed. All mammalian wastes (carcasses and organs) are buried in authorised sites, and since December 2000 are directed to one central incinerator. Cattle in Israel are not fed with mammalian MBM, in practice since the early seventies due to economical considerations, and by law since August 1996. Poultry and fishmeals are still allowed to be fed to cattle.

It is possible to estimate the system stability as good, and the internal threat as minimal.

The Actual Hazard (the Interaction of the Total Threat and Stability in Time)

The risk of an outbreak of BSE in Israel is the result of the interaction of the system stability and the external threat in the relevant period. In a stable system exposed to an external threat, the internal threat will be minimal, because without recycling the penetrating disease agent is bound to disappear with time. In an unstable system exposed to an external threat, the agent will spread through the cattle MBM. Some of the cattle, when reaching the “right” age, will turn out to be clinical cases of BSE. Others will be recycled, magnifying the amount of infected material and developing the disease into an epidemic.

The minimal period needed to diagnose the internal threat in an unstable country exposed to BSE is at least one “incubation period” of 5 years. The period could be the multiplication of few such periods and longer according to the extent of exposure to the BSE agent (the system stability, the size of the cattle population, the age dynamics of the population) and the quality of the monitoring system.

Of the four possible combinations, we estimate that the expected one in Israel is either [a stable system * none or a minimal external threat] or [a stable system * a high external threat]. The first alternative is the less hazardous, but even in the second one the system is able, with time, to remove the BSE agents. The choice between those two alternatives (the actual situation in Israel) depends in our case on the credibility of the British, French and German Veterinary Services and the efficiency of the control measures applied by the IVSAH.

It can not be over-emphasised that all mutual veterinary activities that accompany international trade, regarding BSE as well as all other diseases, are necessarily based on that credibility and certification.

The Actual Situation, the Efficiency of the Monitoring System

The efficiency of the monitoring system depends on the efficiency of the clinical system, the validity of the sample monitored, and the diagnostic methods applied.

The clinical monitoring and reporting system in the Israeli cattle industry is probably among the most efficient in the world, due to the fact that over 90% of the bovine veterinary practice in Israel is comprehensive, given under contract, and provided by a central, country-wide organisation ("Hachaklait"). Compensation for wastes and fallen stock is regulated by a state-compulsory insurance scheme, so that clinical follow up of fallen stock is guaranteed. The awareness of the system to the disease is well developed through lectures and pamphlets; the first of them described the symptoms of the disease to all the parties involved as early as 1989. The disease is notifiable in Israel since April 1992.

The present diagnostic methods allow diagnosis of the BSE agent only after death, and only when the disease is in its clinical stage or towards the end of the incubation period. The Pathology Department of the Kimron Veterinary Institute (KVI) is able to diagnose the disease since 1992 and maintains active surveillance.

In the years 1997 to 1999 for example, the KVI examined 586 brains of cows older than 36 months, all proved to be BSE negative. The Israeli bovine population in that age group is about 120,000; it is possible to calculate the probabilities of diagnosing infected cows if the disease actually exists in Israel. In a random sample, 2800 brains of cattle should have been examined annually to establish that the disease incidence in Israel is smaller than 0.1%. In Israel most of the brains of cattle showing nervous symptoms are sent to the KVI because of the compulsory obligation to examine it for rabies. 162 cows that showed nervous symptoms before their death were examined in the KVI in the period 1997 through 1999. It is possible to estimate on basis of that selected sample that the disease incidence of BSE, if exists, is smaller than 0.01%.

Import of Bovine Meat

It is believed that the prions responsible for BSE are not found in cattle younger than 30 months. No meat from Britain was allowed import since - the latest - 1986 (an official ban was applied in 1989). Import from other countries was allowed after evaluating the quality and credibility of the exporting country's State Veterinary Services by means of a detailed questionnaire with special emphasis upon BSE surveillance and the use of MBMs, and receiving a valid BSE risk analysis as demanded by the guidance of the OIE until mid December 2000. In practice we set an age limit for imported meat (36 months from South America, and 24 months from Europe).