Comparative pathogenesis of two genotype VI.2 avian paramyxovirus type-1 viruses (APMV-1) in pheasants, partridges and chickens

Newcastle disease (ND) is caused by virulent forms of <i>avian paramyxovirus</i>-1 (APMV-1) and is an economically important disease of poultry world-wide. Pigeon paramyxovirus 1 (PPMV-1), a sub-group of APMV-1 is endemic in <i>Columbiform</i>es and can cause infections of poultry. An outbreak of ND in partridges in Scotland, UK, in 2006 (APMV-1/partridge/UK(Scotland)/7575/06) was identified as a class II, genotype VI.2.1.1.2.1, more commonly associated with PPMV-1. It has been hypothesized that game birds may be a route of transmission into commercial poultry settings due to the semi-feral rearing system, which potentially brings them into contact with both wild-birds and poultry species. Therefore, the pathogenesis and transmission of APMV-1/partridge/UK(Scotland)/7575/06 in game birds and chickens was investigated, and compared to a contemporary PPMV-1 isolate, PPMV-1/pigeon/UK/015874/15. Viral shedding and seroconversion profiles demonstrated that pheasants were susceptible to infection with APMV-1/partridge/UK(Scotland)/7575/06 with limited clinical signs observed although they were able to excrete and transmit virus. In contrast, partridges and pheasants showed limited infection with PPMV-1/pigeon/UK/015874/15, causing mild clinical disease. Chickens, however, were productively infected and were able to transmit virus in the absence of clinical signs. From the data, it can be deduced that whilst game birds may play a role in the transmission and epidemiology of genotype VI.2 APMV-1 viruses, the asymptomatic nature of circulation within these species precludes evaluation of natural infection by clinical surveillance. It therefore remains a possibility that genotype VI.2 APMV-1 infection in game birds has the potential for asymptomatic circulation and remains a potential threat to avian production systems. <b>RESEARCH HIGHLIGHTS</b>Demonstration of infection of game birds with Pigeon paramyxovirus-1 (PPMV-1).There are differing dynamics of infection between different game bird species.Differing dynamics of infection between different PPMV-1 isolates and genotypes in game birds and chickens. Demonstration of infection of game birds with Pigeon paramyxovirus-1 (PPMV-1). There are differing dynamics of infection between different game bird species. Differing dynamics of infection between different PPMV-1 isolates and genotypes in game birds and chickens.

新城疫（Newcastle disease, ND）由禽副黏病毒1型（avian paramyxovirus-1, APMV-1）强毒株引发，是全球范围内对家禽产业具有重大经济影响的疫病。鸽副黏病毒1型（Pigeon paramyxovirus 1, PPMV-1）作为APMV-1的一个亚群，在鸽形目（Columbiformes）鸟类中呈地方性流行，且可感染家禽。2006年英国苏格兰地区暴发的鹧鸪新城疫（毒株APMV-1/partridge/UK(Scotland)/7575/06）被鉴定为II类基因型VI.2.1.1.2.1，该基因型通常与PPMV-1相关。有假说提出，由于猎禽采用半散养饲养模式，使其同时接触野生鸟类与家禽，因此猎禽可能成为商业家禽养殖场的病毒传播媒介。为此，本研究针对毒株APMV-1/partridge/UK(Scotland)/7575/06在猎禽与鸡中的致病机制与传播特性展开探究，并与同期分离的PPMV-1毒株PPMV-1/pigeon/UK/015874/15进行对比。

病毒排毒与血清转化特征显示，雉鸡对毒株APMV-1/partridge/UK(Scotland)/7575/06易感，尽管可排毒并传播病毒，但仅观察到轻微临床症状。与之相反，鹧鸪与雉鸡对PPMV-1/pigeon/UK/015874/15的感染程度有限，仅引发轻度临床疾病。而鸡可被有效感染，且在无临床症状的情况下实现病毒传播。

基于上述研究数据可推断：尽管猎禽可能在VI.2基因型APMV-1病毒的传播与流行病学循环中发挥作用，但该类物种内的感染呈无症状特征，使得通过临床监测评估其自然感染变得困难。因此，猎禽中的VI.2基因型APMV-1感染存在无症状循环的可能性，并对禽类生产系统构成潜在威胁。

**研究亮点（RESEARCH HIGHLIGHTS）**
证实猎禽可感染鸽副黏病毒1型（PPMV-1）。
不同猎禽物种的感染动态存在差异。
不同PPMV-1分离株及基因型在猎禽与鸡中的感染动态存在差异。
证实猎禽可感染鸽副黏病毒1型（PPMV-1）。
不同猎禽物种的感染动态存在差异。
不同PPMV-1分离株及基因型在猎禽与鸡中的感染动态存在差异。