Annex A
Distribution of TSE Infectivity in
Tissues and Body Fluids
The following tables present current information on the distribution of TSE infectivity in tissues and body fluids based on data from experimental studies, where available, and on information from other studies of natural TSE disease in humans and animals. A knowledge of the likely distribution of infectivity in tissues is important in deriving risk assessments for experimental work with tissues potentially infected with TSEs. However, the risk assessments must be updated as further information becomes available. The following tables must only be used as a guide to assist in deriving local risk assessments, which need to take into account other factors such as the origin of the TSE agent.
Table A.1
Catagorisation of tissues based on infectivity titres in tissues and body fluids from naturally infected goats and Suffolk sheep with clinical Scrapie (see also Table A.2) |
|---|
|
| Category | High infectivity | Medium infectivity | Low infectivity | No detectable infectivity |
|
| Sheep and goats | | brain
spinal cord | colon-proximal
ileum-distal
lymph nodes
pituitary gland
rectum-distal+
spleen
tonsil | adrenal gland
bone marrow**
cerebrospinal fluid
colon-distal
liver**
lung**
nasal mucosa
pancreas**
sciatic nerve
thymus** | blood clot
faeces
fetus
heart
kidney
mammary gland
milk
muscle-skeletal
ovary
placentao
saliva
salivary gland
seminal vesicle
serum
testis
thyroid
uterus |
|
Based on data derived from Hadlow W. J. et al, 1980, 1982; and from tables produced by the World Health Organisation Consultations 12-14 November 1991 and 17-19 May 1995, and the European Commission 14-15 September 1993.
+ = not assayed but high content of lymphoreticular tissue ** = trace or exceptional
o = positive in other studies (Pattison et al 1972, 1974) |
|
Table A.2
Infectivity in tissues based on other studies of natural disease |
|---|
|
Other tissues in which infectivity is assumed or known as a result of other studies of natural disease include:
| Other tissues which have shown NO detectable infectivity in other studies of natural disease include:
|
| cornea | - iatrogenic CJD | CJD: |
| dura mater | - iatrogenic CJD | faeces, hair, saliva, skin, sweat, tears and |
| kidney | - kuru and CJD | urine |
| lung | - CJD |
| pituitary gland | - iatrogenic CJD | Scrapie: |
| placenta | - scrapie, sheep | colostrum (in one pre-clinical sheep tested), |
| retina | - BSE | skin |
| |
| | BSE:
abomasum, buffy coat, distal colon, embryos, epididymis, fetal calf blood, fetal fluids, midrum fat, muscles with cranial or spinal nerve supply,
oesophagus, optic nerves, prostate,
proximal small intestine, reticulum, rumen omasum, semen, skin, splanchnic nerves, tibial nerves, trachea (cartilage), uterine caruncle (pregnant cow) |
|
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