Asian-origin H5N8 highly pathogenic avian influenza (HPAI) viruses of the H5 Goose/Guangdong/96 lineage, clade 2.3.4.4 group B, reached South Africa by June 2017. By the end of that year, 5.4 million layers and broiler chickens died or were culled, with total losses in the poultry industry estimated at US$ 140 million, and thousands of exotic birds in zoological collections, endangered endemic species and backyard poultry and pet birds also perished. The 2017 H5N8 HPAI outbreaks were characterized by two distinct spatial clusters, each associated with specific reassortant viral genotypes. Genotypes 1, 2, 3 and 5 were restricted to the northern regions, spanning the provinces of Limpopo, Gauteng, North West, Mpumalanga, KwaZulu-Natal and Free State. The second, much larger cluster of outbreaks was in the south, in the Western and Eastern Cape provinces, wherein 2017 and 2018 outbreaks were caused solely by genotype 4. The last confirmed case of H5N8 HPAI in the northern region in 2017 was in early October, and the viruses seemed to disappear over the summer. However, starting in mid-February 2018, H5N8 HPAI outbreaks resurged in the north. Viruses from two of the eight outbreaks were sequenced, one from an outbreak in quails (Coturnix japonica) in the North West Province, and another from commercial pullets in the Gauteng province. Phylogenetic analysis identified the viruses as a distinct sixth genotype that was most likely a new introduction to South Africa in early 2018.

中文翻译：

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南非北部地区2018年爆发的枝条2.3.4.4 H5N8高致病性禽流感与2017年的爆发无关。

H5鹅/广东/ 96谱系的亚洲起源的H5N8高致病性禽流感（HPAI）病毒，进化枝B.2.3.4.4组在2017年6月之前到达南非。到那年底，有540万层鸡和肉鸡死亡或被淘汰，家禽业的总损失估计为1.4亿美元，成千上万的动物珍禽，濒临灭绝的特有物种以及后院家禽和宠物鸟也丧命。2017年H5N8高致病性禽流感暴发的特征是两个不同的空间簇，每个簇都与特定的重配病毒基因型相关。基因型1、2、3和5仅限于北部地区，横跨林波波省，豪登省，西北部，姆普马兰加省，夸祖鲁-纳塔尔省和自由邦省。第二个更大的爆发群是在南部，在西开普省和东开普省，其中2017年和2018年的暴发仅由基因型4引起。最后确诊的H5N8 HPAI病例是在2017年北部地区，发生在10月初，病毒似乎在夏天消失了。但是，从2018年2月中旬开始，北部再次爆发H5N8高致病性禽流感。对八次暴发中的两次暴发的病毒进行了测序，一种来自西北省鹌鹑（Coturnix japonica）暴发，另一种来自豪登省的商业小母鸡。系统发育分析确定该病毒为独特的第六种基因型，极有可能在2018年初被引入南非。而且病毒似乎在整个夏天消失了。但是，从2018年2月中旬开始，北部再次爆发H5N8高致病性禽流感。对八次暴发中的两次暴发的病毒进行了测序，一种来自西北省鹌鹑（Coturnix japonica）暴发，另一种来自豪登省的商业小母鸡。系统发育分析确定该病毒为独特的第六种基因型，极有可能在2018年初被引入南非。而且病毒似乎在整个夏天消失了。然而，从2018年2月中旬开始，北部再次爆发H5N8高致病性禽流感。对八次暴发中的两次暴发的病毒进行了测序，一种来自西北省鹌鹑（Coturnix japonica）暴发，另一种来自豪登省的商业小母鸡。系统发育分析确定该病毒为独特的第六种基因型，极有可能在2018年初被引入南非。