African swine fever: a New Zealand perspective on epidemiological risk factors for its occurrence

Abstract

This article reviews key epidemiological and clinical features of African swine fever (ASF). We identify particular aspects of New Zealand's pig populations (commercial, non-commercial, and wild) that may affect the risk of disease entry or spread. Review of published literature is supplemented by analysis of demographic and spatial aspects of the New Zealand commercial, non-commercial, and feral pig populations to provide context around risk factors for the disease that are most relevant to New Zealand. The current Eurasian outbreak of ASF, including recent spread into Oceania, has increased the risk of an incursion of the disease into New Zealand. Large volumes of fresh pork importation (including from countries affected by ASF), large non-commercial pig populations with substantial spatial overlap with the country's commercial industry, limited monitoring of compliance with waste food feeding regulations, and lack of mandatory premises identification for noncommercial pig holdings would likely contribute to the risk of spread of ASF in the event of an incursion. Awareness amongst veterinarians of these risk factors will contribute to national biosecurity and disease preparedness efforts in New Zealand.

Epidemiological Characterization of African Swine Fever Dynamics in Ukraine, 2012–2023

“…Even though more than 70% of the reported outbreaks before 2015 were in wild boar, it is impossible to determine with certainty if it was the wild boars that were responsible for the introduction of ASF into the country. Inadvertent import and dissemination of the virus with pork products or live animals is a known risk factor for ASF spread [ 31 ]. It is not unlikely to have played a role in Ukraine, and provides a likely explanation for the isolated 2012 outbreak in Zaporozhye.…”

“…Because of these difference in habitats as well as to account for potential differences related to climate, we differentiated between the three southern oblasts Kherson, Odesa and Mykolaiv adjacent to the Black Sea and the other primarily more northern regions ( Figure 2 ). A colder climate with low temperatures in the winter could increase ASFV survival in the environment, such as in carcasses, and the data from the northern wild boars indeed show more cases in the cold months (November–February) [ 30 , 31 , 42 ]. This pattern of seasonality has also been observed in Poland and in Lithuania [ 44 , 54 ].…”

“…In Europe, ASF has progressed westward in a slow wave advancing through the wild boar population with spillover into domestic pig populations in all sorts of farming systems [ 1 , 19 , 24 , 25 ]. Infectious ASFV can survive for an extended period in the environment, such as in carcasses and on fomites, but also remains infectious in meat products made from infected animals and thus can inadvertently be carried long distances and across borders by human travel activities [ 1 , 26 , 27 , 28 , 29 , 30 , 31 ]. This makes ASFV very versatile in its modes of spread, and, depending on the country, the epidemiological situation and outbreak dynamics can differ significantly.…”

Biosecurity is critical to New Zealand’s national security, economy and way of life

“…The spread of the disease in 2018 has stimulated an expansion of the GF-TADs learning network approach to support countries as they deal with epidemic outbreaks and evolving endemicity. The potential for further expansion into the Oceania region is a significant concern, driving heightened risk management and preparedness (Kurian et al 2021).…”

Development and Validation of a Bioinformatic Workflow for the Rapid Detection of Viruses in Biosecurity

“…Similar consequences may occur with the introduction of the viruses responsible for African swine fever and Lumpy skin disease—losses of production and export value, as well as eradication, compensation, and surveillance costs may have considerable economic impact on primary industries [ 6 , 7 ]. Although these viruses are currently absent from NZ there are increasing concerns for their introduction into Australia, a major trading partner of NZ [ 8 , 9 , 10 , 11 ]. To address the ever-increasing risk of virus incursions, high-throughput sequencing (HTS) is now becoming routine within the NZ biosecurity sector, particularly when performing plant virus diagnostics [ 12 ].…”