Global AI Situation Update
Since our last issue, H5N2 and H5N8 highly pathogenic avian influenza (HPAI) activity in North America has subsided. Canada declared freedom from HPAI in poultry in October 2015, and the costly outbreaks of H5N2 and H5N8 across 21 states in the USA reportedly resolved, with the last case detected in June 2015. In total, 211 commercial and 21 backyard poultry premises were affected in the USA between December 2014 and June 2015, with a total estimated cost of USD $950 million.
Concerns remain that seasonal outbreaks may continue as a result of migratory waterfowl activity. The role of migratory birds in the spread of HPAI in North America remains unclear, but phylogenetic analysis suggests commingling of infected birds may promote re-assortment of Asian HPAI strains with local low pathogenic avian influenza (LPAI) viruses. A study by the University of NSW on outbreaks in the Midwest of the USA found that timing of waterfowl migration played an important role in combination with high poultry densities and local farm factors.
The US Department of Agriculture, Animal and Plant Health Inspection Service (APHIS) have updated their preparedness and response plan for future HPAI incursions.
Meanwhile, a new virus serotype (H7N8) was detected during routine surveillance in January, marking the first report of H7N8 in the USA. To date, nine outbreaks of H7N8 LPAI and HPAI have been reported in poultry in Indiana.
Influenza A reports since the last issue:
The WHO reported a human case of H5N1 in Bangladesh. Cases of H5N1 HPAI were reported in poultry in Cambodia, Cote d'Ivoire, France, India, Nigeria and Vietnam; and in poultry and wild birds in Ghana. H5N1 LPAI was reported in poultry in Scotland.
H5N2 HPAI was reported in poultry in France and Taiwan, while H5N2 LPAI was reported in France and Germany (poultry); and South Africa (ostriches).
France reported cases of H5N3 LPAI in poultry.
Cases of H5N6 HPAI occurred in poultry in Laos and Vietnam; and in wild birds in Hong Kong. China reported five additional human cases and an outbreak in peacocks and black swans.
Further cases of H5N8 HPAI were reported in poultry in Taiwan and South Korea.
France reported outbreaks of H5N9 HPAI in ducks, marking the first detection of the subtype in Europe.
Gaza Strip reported an outbreak of H5 HPAI to the OIE. Details of the specific neuraminidase protein and affected species are unknown.
Since 1 October 2015, China has reported 23 additional human cases of H7N9, bringing the global total to 711 cases as of 13 January 2015 (691 in China; 13 in Hong Kong; 4 in Taiwan [all imported]; 2 in Canada; and 1 in Malaysia).
The WHO reported two human cases of H9N2 in Bangladesh dating back to February and October 2015.
Middle East Respiratory Syndrome (MERS)
Since our last issue, additional cases of the novel coronavirus MERS-CoV were reported in Oman (1), Jordan (5), and Saudi Arabia (31). As of 11 January 2016, 1626 human cases have been confirmed across 26 countries, resulting in 586 deaths.
The Republic of Korea declared freedom from the disease on 23 December 2015.
Findings from a recent publication in Science support camels as the reservoir for co-circulation of various camel and human coronavirus species. Trials to develop a vaccine for camels are ongoing.
The WHO declared that human-to-human transmission of Ebola in Guinea and Liberia has ended. However, a further case was confirmed in Sierra Leone in January, bringing the total to 28,638 human cases and 11,316 deaths since the outbreak in West Africa commenced in March 2014.
A recent report from the USA confirmed a case of rabies in a dog imported from Egypt under a falsified vaccination certificate. This serves not only to remind us of the importance of Australia’s import conditions for rabies, but also that quarantine borders can be breached. It is important to promptly investigate and report any cases of potential rabies.
A study from India reported natural rabies infection in a domestic chicken following a dog bite incident. Experimental infection of birds with rabies has been documented, but few reports of naturally occurring infections exist.
In December 2015 the FAO, OIE and WHO jointly convened a global conference in Geneva for the eradication of dog-mediated human rabies. The proposed strategy adopts a collaborative One Health approach to combine dog vaccination, education and improved access to human post-exposure prophylaxis.
Bluetongue virus (BTV)
In Vol. 9 Issue 1 we noted increased bluetongue virus serotype 4 (BTV-4) activity in southern Europe during summer and autumn of 2014. This seasonal pattern has continued in 2015, with outbreaks in Austria, Croatia, Greece, Romania and Turkey. Further cases in Bosnia and Herzegovina, Georgia, Hungary and Slovenia are yet to be serotyped.
In August 2015, BTV-8 was detected in France for the first time since 2010. As of January 2016, 143 outbreaks have been reported in sheep and cattle. Targeted vaccination for export has commenced.
In September 2015 Canada detected BTV-13 in beef cattle in Ontario. BTV-13 is endemic to the USA, but this marks the first detection of this serotype in Canada.
Carp herpesvirus 3
Researchers at CSIRO are investigating whether Carp herpesvirus 3 (aka Cyprinid herpesvirus 3 or CyHV3) could be used as a biocontrol agent to eradicate invasive populations of carp in Australia’s waterways. Trials to date have shown that the virus selectively kills invasive carp, without affecting native fish species.
Classical swine fever (CSF)
In May 2015, Australia was among the first countries to receive official CSF-free status from the OIE. Such recognition has important implications for Australia’s trade and market access opportunities. However, the disease remains endemic in many neighbouring countries, and Australia faces the constant threat of re-introduction. Early detection and laboratory confirmation of CSF is key to effective disease control. It’s important that Australian veterinarians remain alert to exotic disease risks, to ensure rapid recognition and response to a potential outbreak.
Would you be able to recognise a case of CSF? If not, see Emergency Animal Disease Bulletin - No 113
A study of food-producing animals in China detected the first polymyxin resistance mechanism, the MCR-1 gene, in E.coli. The MCR-1 gene has been shown to confer resistance to polymyxin antibiotics, notably polymyxin B and polymyxin E (colistin). Until now, polymyxins were the last group of antibiotics with no identified resistance. As the MCR-1 gene is plasmid-mediated, there is concern polymyxin resistance may transfer between microorganisms and drive the emergence of pan-drug resistance (PDR). The MCR-1 gene has since been detected in humans and production animals in Europe, Northern Africa, North America and South East Asia.
A publication in Emerging Infectious Diseases reports identification of a new genus of the Orthomyxoviridae family, provisionally known as influenza D virus, involved in respiratory disease in pigs and cattle in Italy. Further research is required to determine the zoonotic potential of influenza D.
Hotspots for bat viruses
Researchers developed a spatial empirical model to investigate drivers for zoonotic viral transmission from bat populations globally. The study maps risk levels and highlights processes underlying zoonotic disease emergence.
You may be looking at the first case and you do not want to become famous as the vet who missed it!
Use the hotline number 1800 675 888 or contact your local government vet. You are not alone.