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Highly Pathogenic Avian Influenza A(H5N8) Virus, Democratic Republic of the Congo, 2017

2018; Centers for Disease Control and Prevention; Volume: 24; Issue: 7 Linguagem: Inglês

10.3201/eid2407.172123

1080-6059

Augustin T. Twabela, Georges Mbuyi Tshilenge, Yoshiro Sakoda, Masatoshi Okamatsu, Ezekiel Bushu, P. Koné, Lidewij Wiersma, Gianpiero Zamperin, Alessandra Drago, Bianca Zecchin, Isabella Monne,

Animal Disease Management and Epidemiology

In 2017, highly pathogenic avian influenza A(H5N8) virus was detected in poultry in the Democratic Republic of the Congo.Whole-genome phylogeny showed the virus clustered with H5N8 clade 2.3.4.4B strains from birds in central and southern Asia.Emergence of this virus in central Africa represents a threat for animal health and food security.T he detection of highly pathogenic avian influenza (HPAI) infections in poultry has greatly increased in the past decades, in particular as a consequence of the spread of the HPAI virus subtype H5, descendent of the H5N1 virus A/goose/Guangdong/1/1996 (Gs/GD), which was detected in China in 1996 (1).The evolution of the Gs/ GD H5 lineage has resulted in the emergence of multiple clades characterized by distinct antigenic properties and zoonotic potential (2).Among them, the HPAI H5 clade 2.3.4.4 has stood out for its concerning ability to reassort and combine with different neuraminidase (NA) subtypes and to spread rapidly to and within multiple continents (3).In late 2016, a reassortant HPAI H5N8 virus (clade 2.3.4.4 group B) began to spread from China (4) and the Russian Federation (5) to Asia, the Middle East, Europe, and western Africa and for the first time reached central, eastern, and southern Africa.Egypt, Tunisia, and Nigeria reported HPAI H5N8 virus in late autumn 2016, and virus detection continued to occur across Africa in the winter, spring, and summer of 2017 ( 6).This study provides insights from the epidemiologic and viral genome analysis on the outbreaks in the Democratic Republic of the Congo (DRC). The StudyIn late April 2017, high death rates in domestic chickens and ducks were reported in 4 localities of the Ituri province (Bunia territory) of DRC, which is situated at the edge of Albert Lake between the Rwenzori Mountains and the Republic of Uganda (Figure 1).Because this outbreak followed an HPAI H5N8 outbreak in Uganda in January 2017 (7,8), this alert led to a strong suspicion of HPAI.Clinical signs in the affected poultry included prostration, dyspnea, yellowish-colored diarrhea, generalized weakness, torticollis, and, in some cases, recumbency before death.Necropsies on carcasses revealed petechiae, hemorrhage, or both in all organs; hemorrhagic liver with soft consistency; and an empty gizzard with epithelial hemorrhage.We sampled 22 birds (9 duck carcasses, 12 live ducks, and 1 live chicken) in the 4 infected villages.We collected tracheal and cloacal swabs from living birds showing clinical signs and collected organs including lung, intestine, trachea, and heart from dead birds.We performed a rapid test for avian influenza virus (AIV) type A detection in the field using the AIV Ag Test Kit (BioNote, Hwaseong-si, South Korea).Of the 22 birds sampled, 6 ducks tested positive with the rapid test; real-time reverse transcription PCR analysis confirmed 11 H5-positive ducks.The Central Veterinary Laboratory of Kinshasa (Kinshasa, DRC) submitted the samples to the World Organisation for Animal Health (OIE) Reference Laboratory and the Food and Agriculture Organization of the United Nations (UN-FAO) Reference Center for Animal Influenza at the Istituto Zooprofilattico Sperimentale delle Venezie (Legnaro, Italy) for confirmatory diagnosis and genetic analysis.Using an Illumina MiSeq platform (Illumina, San Diego, CA, USA), we obtained whole-genome sequences for 4 viruses selected as being representative of the 4 affected areas in Ituri province (Table 1; online Technical Appendix Table 1, https://wwwnc.cdc.gov/EID/article/24/7/17-2123-Techapp1.pdf).We submitted the full genomes to GenBank (accession nos.MG607401-32) (Table 1; online Technical Appendix 1 Table 1) and used the