Two threats highlighted in the shadow of COVID-19

In March 2020, ASF was reported in the Highlands region of PNG. ASF is a contagious viral disease of pigs that is transmitted via contact between animals. It is also transmitted through human activities such as feeding pigs contaminated kitchen waste. It has a very high mortality rate and has been known to kill 100% of infected pigs. There is no vaccine for ASF and no effective treatments.

While ASF does not infect humans and infected pork is safe to eat, pigs are central to the life of PNG’s Highlanders—for food, economic, cultural and ceremonial purposes—so the disease has the potential to be devastating. If ASF spreads to the cities of Port Moresby and Lae, commercial piggeries located there would also be at risk.

Since 2019 an ACIAR-supported project has been developing surveillance strategies to help detect mosquito-borne viral diseases that affect both animals and people. The project is also supported by the Australian Government’s Department of Foreign Affairs and Trade (DFAT) as a One Health project. Now, with additional funding from ACIAR, the project team is extending its scope to provide further support to the national ASF response.

An ACIAR-DFAT One Health project has been developing surveillance strategies to help detect mosquito-borne viral diseases in PNG. Now, with additional funding, the work will encompass African swine fever.

Working from the Commonwealth Scientific and Industrial Research Organisation’s (CSIRO) Australian Centre for Disease Preparedness (ACDP), project leader Dr David Williams says the team aims to increase PNG’s capacity to rapidly and accurately detect any incursions of ASF using diagnostic tests to ensure the country can mobilise its response.

‘We were already using pigs at our sentinel sites that are set up to track the presence of the mosquito-borne viruses we are monitoring,’ says Dr Williams. ‘It was a natural add-on to include ASF.’

Ten sentinel sites have been established in PNG across three provinces from which samples have been collected for mosquito-borne virus testing by staff from PNG’s National Agriculture Quarantine and Inspection Authority (NAQIA). NAQIA staff also travel into the Highlands to take samples from penned and free-range pigs to test them for ASF virus infections.

‘The challenge with working in the Highlands is that it is very remote and it can take a day or more to get there and return to Port Moresby—and even longer if you have to send samples to Australia to be tested,’ says Dr Williams. ‘It is really important that the local lab has the essential equipment and training to do the testing itself.’ This allows for a more rapid response by local NAQIA field teams to implement control measures to stop the spread of ASF.

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As part of the project, upgraded machinery has been installed at the NAQIA lab in Port Moresby to test for the presence of viral antibodies and proteins to the ASF virus in animal samples. The next step is to support the NAQIA lab to build capability in the ‘gold standard’ for virus testing: genetic tests.

‘Genetic testing is nearly 100% accurate for virus detection, which is an improvement over the existing tests that may only pick up around 70% of samples with the virus,’ says Dr Williams.

To identify which ones work best, ACDP and NAQIA are also testing the accuracy of ASF point-of-care test kits used in the field to provide an early indication of the presence of ASF.

While travel to PNG from Australia is restricted due to COVID-19, Dr Williams and his team are staying in touch with NAQIA and providing remote support. Another project partner, the PNG Institute for Medical Research, is assisting with the training of NAQIA laboratory staff.

With an increasing level of diagnostic capability, NAQIA will be able to independently conduct animal disease testing, test samples faster and be more confident in the test results, ensuring any efforts to control ASF and other livestock diseases are targeted and have maximum impact.

Dr Williams adds that existing surveillance activities at the pig sentinel sites—particularly those in village communities—also provide opportunities to talk to pig owners and farmers about ASF to raise awareness about the disease and what they can do to prevent it.

FAW is an invasive moth pest that has rapidly spread across Africa and Asia since 2016. In early 2020 it was detected for the first time in Australia. As a caterpillar, FAW eats crops including maize, sorghum, cotton, ginger and sugarcane.

FAW can develop resistance to commonly used pesticides and poses a major threat to crop production and food security. As an adult, FAW moths can fly up to 160 km in a single night, allowing them to infiltrate new areas quickly and easily.

FAW was detected in the Western Province of PNG in early 2020 but has not yet been found in other Pacific island countries. ACIAR is stepping up its response to help these countries better understand their FAW situations and develop their capacities to manage the pest.

An existing ACIAR project led by the University of Queensland is already building diagnostic and surveillance capacity for pests and diseases in the Pacific region. The project team will now expand its work to develop and test specific surveillance strategies for FAW, monitor the host plants used by the pest and run workshops to raise FAW awareness in regions where it has not yet invaded.

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In South-East Asian countries, where FAW is well established, the research needs are different. A newly developed ACIAR project will focus on understanding the genetics of fall armyworm led by Australia’s CSIRO and co-funded by the Grains Research and Development Corporation.

The project will provide a greater understanding of the pest’s genetic make-up to inform which pesticides and other practices are the most effective for managing the pest. This knowledge will help to develop effective pest management plans.

Dr Sarina Macfadyen, ACIAR Associate Research Program Manager for Farming Systems Analysis, says she hopes the research will start developing the knowledge needed to guide individual country responses and facilitate co-ordinated actions.

‘FAW can travel easily between countries and across large distances and therefore needs some degree of coordination in response and perhaps management,’ says Dr Macfadyen.

‘The team will develop new knowledge in two areas: firstly, conducting a genetic characterisation of the similarities and differences in the populations found in Australia and the countries in South-East Asia.’ 

There are two strains of fall armyworm that appear identical. One preferentially feeds on rice and pasture grasses and the other feeds on maize. Looking at the genetics will help to determine the ecology of the species better.

‘The second area of research involves testing populations that may already show some level of resistance to commonly used pesticides,’ says Dr Macfadyen. 

This knowledge will feed into the development of resistance management plans by individual countries and inform pesticide recommendations to farmers.

Both ASF and FAW continue to warrant significant attention, even as the world responds to COVID-19. If left unaddressed, their potential to cause further and significant harm to an ever-increasing number of people will increase.

Despite being a relatively small player in the global response to both threats, ACIAR plays a strategic role that fills knowledge and resource gaps where it can have the biggest impact by leveraging existing relationships and projects. 

See ACIAR projects:

• A One Health approach to establish surveillance strategies for Japanese encephalitis and zoonotic arboviruses in Papua New Guinea.
• Characterisation of Spodoptera frugiperda (fall armyworm) populations in South-East Asia and Northern Australia.
• Responding to emerging pest and disease threats to horticulture in the Pacific islands.

• With global attention on COVID-19, ACIAR is ensuring critical attention is given to serious and emerging regional threats to food security.
• African swine fever (ASF) and fall armyworm (FAW) have both become major threats to agricultural production in Pacific island countries.
• Additional support from ACIAR to tackle ASF and FAW, which have the potential to devastate pig and crop production respectively, will help to improve regional biosecurity—including for Australia.