作者：美國愛荷華州立大學(xué)獸醫(yī)學(xué)院 張建強(qiáng)副教授

01

關(guān)于藍(lán)耳病及藍(lán)耳病毒的背景信息

Clinical disease臨床疾病

Respiratory and systemic disease呼吸道疾病

Reproductive disorders繁殖障礙

Neurological disorders神經(jīng)系統(tǒng)障礙

Economic ompact經(jīng)濟(jì)影響

PRRS Virus (PRRSV)

2 types : PRRSV-1 (Typ* 1. European) and PRRSV-2 (Type 2, North American)

now 2 species：Betaarterivirus mid 1 and Betaarterivirui suid 2

PRRSV-1

First identify in Europe in 1990s (Prototype strain: Lelystad strain)

First reported in the U.S. in 1992-1993 but whole-genome sequences determined in 1999

Globally, 4 subtypes (only Subtype 1 in the U.S.)

PRRSV-2

First identified in the U.S. in 1990$ (Prototype strain: VR-2332 strain)

RFIP pattern (cutting pattern by Mlul, Hincll, and Socll) commonly used in the North America

ORFS-based genetic classification system

02

藍(lán)耳病毒在美國的流行狀況

1、所有年齡段的豬及所有檢測的樣品類別（2010-2021四個(gè)實(shí)驗(yàn)室的數(shù)據(jù)）

可常年檢測到藍(lán)耳??；

但有一定的季節(jié)性；

在夏天的檢出陽性率偏低；

藍(lán)耳病毒可以在各個(gè)生產(chǎn)階段（年齡段）的豬只中檢測到；

藍(lán)耳病毒PCR檢出陽性率會(huì)有波動(dòng)；

在種豬群里，藍(lán)耳病毒PCR陽性率很低。

2、PRRSV-1 and PRRSV-2

Data from ISU+ UMN + SDSU+ KSU (from 2007 to 2018)

106,392 PRRSV PCR-positive cases

100,818 cases (94.76%) positive for PRRSV-2

2,289 cases (2.15%) positive for PRRSV-1

3,285 cases (3.09%) positive for PRRSV-1 and PRRSV-2

03

藍(lán)耳病毒的診斷方法

1、PRRSV Diagnostics藍(lán)耳病毒診斷

specimens for testing 用于檢測和診斷的樣品

Pathological and histopathological evaluation 病理及組織病理評佔(zhàn)

Detection of viral nucleic acid, viral antigen, infectious virus 基于核酸,抗原及活病毒的檢測

RT-PCR (duplex for Type 1 & Type 2)

Sequencing 測序

Immunohistochemistry 免疫組化

Direct tissue fluorescence antibody test 組織熒光抗體(FA)方法

Virus isolation病毒分離

Action of antibody 抗體檢測

Detection of antibody 抗體檢測

ELISA (HerdChek-PRRS X3, IDEXX): both Type 1 and Type 2 PRRSVs - Serum, Oral fluid

Indirect fluorescent antibody test (IFA): Serum; could be virus-specific IFA assay 免疫熒光抗體

Virus neutralization test: Serum; could be virus-specific VN test 中和抗體

2、PRRSV Virus Isolation in ZMAC and MARC-145 cells

It is a challenge to isolate PRRSV from oral fluid and processing fluid samples

從口腔液和睪丸/斷尾液里分離藍(lán)耳病毒很困難

Preferred specimen types for PRRSV VI: lung > serum > processing fluid and oral fluid

推薦用于分離藍(lán)耳病毒的樣品類別:肺組織 > 血清>口腔液和睪丸/斷尾液

serum and lung samples: Higher success rate of PRRSV VI in ZMAC than in MARC-145 cells.

When PRRSV VI is Neg in MARC-145 cells, VI attempts in ZMAC cells are recommended

對于肺組織和血清樣品，如果藍(lán)耳病毒分離在MARC-145細(xì)胞時(shí)陰性，建議嘗試ZMAC細(xì)胞

For cost-effectiveness, it is recommended to conduct PRRSV VI from clinical samples with Ct＜30.

建議用 Ct值小于30的肺組織或血清樣品做藍(lán)耳病毒分離,以提高分離成功率

Impacts of PRRSV-2 genetic lineages on VI varied

o LI & L8: VI success rate ZMAC > MARC-145

O L5：success rate similar in ZMAC and MARC-145

Not all of the PRRSV islates obtained in ZMAC cells can grow in MARC-145 cells

不是所有的在ZMAC細(xì)胞分離出的藍(lán)耳病毒株都能在MARC-145 細(xì)胞里生長

3、Is PRRSV in clinical sample and cell culture isolate the sample

995 PRRSV-2 PCR-positive specimens

548 serum, 397 lung,and other 50 sample;

Results can be summarized in three categories

category1: PRRSV-2 strains in clinical samples and MARC-145 and/or ZMAC isolates match each other

category2: Different RFLP (mismatching nucleotides at cutting sites); similar PRRSV-2 in clinical samples and isolates

Category 3:

Similar PRRSV-2 in clinical

04

藍(lán)耳的防控

1、Biosecurity and management

To reduce the probability of introducing PRRSV into negative herds or new PRRSV variants into positive herds

Examples

2.丶Induction of protective immunity

Live virus inoculation (LVI):farm-specific wild-type virus,serum from infected pigs

Autogenous vaccines:killed farm-specific wild-type virus isolate

Commercial killed vaccines

Commercial modified live virus (MLV) vaccines

3、Supplemental prophylactic and therapeutic measures

During an acute outbreak,administer anti-inflammatories to control fever and antibiotics to manage secondary bacterial infections

Ivermectin:effectiveness?