GB/T 19180-2020Diagnostic techniques for bovine spongiform encephalopathy (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This standard replaces GB/T 19180-2003 "Diagnostic Technology of Bovine Spongiform Encephalopathy". This standard is compared with GB/T 19180-2003, except In addition to editorial changes, the main technical changes are as follows:

---Added the scope of application of H·E histopathological staining method, immunohistochemical method and western blotting method, and deleted "also available Used in the diagnosis of infectious spongiform encephalopathy in other animals" (see Chapter 1);

---Optimized the description of clinical symptoms (see 4.3);

---Optimized the operation steps of H·E histopathological staining method (see 5.1) and immunohistochemistry method (see 5.2);

---Added immunoblotting method (see 5.3).

Introduction

Bovine Spongiform Encephalopathy (BSE) is a chronic lethality of cattle caused by prions Neurological diseases pose great harm to animals and humans. The World Organization for Animal Health (OIE) lists it as an animal that has a serious impact on international trade One of the diseases, our country classifies it as a kind of animal diseases. The current "Diagnostic Technology of Bovine Spongiform Encephalopathy" (GB/T 19180-2003) It was promulgated by the former General Administration of Quality Supervision, Inspection and Quarantine on June 4, 2003 and implemented on December 1, 2003. This standard only includes clinical Three diagnostic methods, including symptoms, histopathology, and immunohistochemistry, do not include another diagnostic method specified by the OIE Terrestrial Animal Manual, namely Western blot. Western blotting method is more sensitive and specific than immunohistochemical method. Therefore, the immunoblotting method is bovine spongiform brain A better diagnosis method in disease diagnosis technology, it can better serve the monitoring of mad cow disease in my country.

BSE is divided into typical BSE and atypical BSE. Typical BSE is caused by cattle eating meat and bone meal or feed contaminated with cattle and sheep prions. Caused, atypical BSE is a sporadic BSE that occurs naturally. Under natural conditions, BSE is transmitted through the digestive tract, and no horizontal and vertical Evidence of direct transmission. The incubation period of typical BSE is generally 2 to 8 years, with an average of 4 to 5 years. It occurs mostly in cattle aged 4 to 6 years. It is rare, and it decreases significantly over 6 years old. According to the molecular weight of the pathogen, atypical BSE is divided into H type and L type. Atypical BSE The average age of onset is 11 years old. The course of BSE usually lasts from several months to a year, and eventually death.

Most BSE cattle have no typical clinical symptoms, so the diagnosis of BSE should be achieved through laboratory testing. The pathogen of BSE is Isoforms of prion protein in the organism, BSE prion antibodies cannot be detected in sick bovine serum, so serological detection methods are suitable for BSE It is meaningless. At present, most laboratory diagnostic methods are aimed at detecting the pathogen of BSE, including immunohistochemical methods and western blotting methods. Methods, ELISA methods, etc., among which immunohistochemical methods and western blotting methods are BSE diagnostic methods specified in the OIE manual. BSE disease The bovine central nervous system is damaged by prions, and spongy vacuole degeneration will occur. If the central nervous system is well preserved and autolysis has not occurred, use H·E histopathological staining method can observe these lesions. The OIE manual stipulates that the H·E histopathological staining method is the diagnosis of BSE When using immunohistochemical methods to diagnose BSE, the H·E histopathological staining method should be used to assist the diagnosis;

When using Western blotting to diagnose BSE, if the sample is suitable for H·E histopathological staining, then H·E should also be used at the same time. Histopathological staining method assists the diagnosis.

1 Scope

This standard specifies the technical requirements for clinical diagnosis, laboratory diagnosis and comprehensive determination of BSE diagnosis.

This standard is applicable to the diagnosis of BSE, in which clinical diagnosis is applicable to the monitoring and epidemiological investigation of BSE, and H·E histopathological staining The color method is suitable for the pathological diagnosis of the central nervous system of BSE, and the immunohistochemical method and western blot method are suitable for the etiology of BSE diagnosis.

2 Abbreviations

The following abbreviations apply to this document.

BSE. Bovine Spongiform Encephalopathy

H·E. Hematoxylinandeosin

HRP. Horseradish peroxidase (Horseradishperoxidase)

PBS. Phosphate buffered solution (Phosphatebufferedsolution)

PK enzyme. Proteinase K (ProteinaseK)

PVDF. Polyvinylidenefluoride

SDS. Sodium dodecylsulfate (Sodiumdodecylsulfate)

TBST. Isotonic buffered salt solution (Tris-HClbuffered solutionwithTween)

3 Clinical diagnosis