Serological monitoring of especially dangerous animal diseases

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Serological monitoring of especially dangerous animal diseases

Introduction

global surveillance swine fever

Today more than ever, outbreaks of some animal diseases, particularly those harmful to humans (zoonoses) can cause considerable economic and social upheaval and send a wave of panic across the globe. The recent health crises due to bovine spongiform encephalopathy and foot-and-mouth disease are a good illustration of this new trend. The current avian influenza epizootic also shows how a serious health event for the animal kingdom can have a global impact on the rural economy and consumers and constitute a threat to public health.

Globalisation is a factor that facilitates the appearance of emerging and re-emerging diseases and considerably magnifies their impact. National Veterinary Services are crucial to prevention, detection and monitoring of animal diseases, including diseases transmissible to humans. They play a key role in all countries as guarantors of animal health and, by association, of public health. Their mission is the responsibility of the public authorities, with the involvement of private-sector partners.

In many countries, development and growth depend on agricultural performance, in terms of production, quality and safety of products of animal origin. That performance is directly linked to the quality of national Veterinary Services. To be efficient, Veterinary Services must operate according to scientific principles and in complete transparency, be technically independent and free of political and private-sector pressure. The OIE reiterates its affirmation that Veterinary Services are a global public good and that bringing them into line with international standards (structure, organisation, resources, capacity, role of the private sector and para-professionals) is a priority public investment.

The current avian influenza crisis is further proof that, without effective Veterinary Services, countries are unable to prevent the introduction or emergence and re-emergence of animal diseases or to bring outbreaks under control when they do occur. Countries with inefficient Veterinary Services cannot provide credible guarantees to their trade partners of the safety of the products of animal origin they wish to export.

The OIE undertook to produce international standards on the quality of governance of Veterinary Services and to help its member countries apply them.

The OIE's standards on the quality and assessment of Veterinary Services were democratically and unanimously adopted by its 167 members. In order to facilitate the implementation of the standards, the OIE, with the initial support from the Inter-American Institute for Cooperation on Agriculture (IICA), developed an interactive application for evaluating the quality of Veterinary Services on the basis of the adopted standards. The application, called «Performance, Vision and Strategy» (PVS), is designed to serve as a guide to help countries comply voluntarily with OIE standards through a process of self-evaluation, evaluation at the request of a trade partner or evaluation by a third party under the auspices of the OIE.

Use of PVS to monitor closely the various constituents of the OIE standards will be the topic of a training course for a team of OIE experts from the different regions so they can act as facilitators for the evaluation process and support OIE member countries. Whether for an individual country that wishes to conduct a self-evaluation, a group of countries that wants to conduct reciprocal evaluations to facilitate trade between them, or a country that wants to be evaluated by a third party under the supervision of the OIE, these experts will ensure the consistency of the evaluation process.

Organisations that fund economic development, the World Bank in particular, have supported the OIE initiative to promote the use of PVS worldwide and have requested the OIE's assistance in conducting voluntary evaluations in more than 100 developing and transition countries that meet the requisite conditions. The World Bank and the international community recognise the need for quality Veterinary Services, not only to control the current avian influenza crisis but also to prevent and bring other emerging or re-emerging diseases under control rapidly.

The evaluation of Veterinary Services using PVS, coordinated by the Central Bureau of the OIE, supported by its Regional Representations and offices on the five continents, will play a vital role in the preparation and definition of country investments needed to prevent and control disease on a global scale.

The evaluation data generated by PVS will enable the entire donor community to target investments, with the overarching goal of assisting countries that so wish to bring their services into line with international standards adopted democratically by all. The economic justification for these investments can be easily demonstrated: the cost of disease prevention is tiny in comparison with the cost of health crises; and appropriate animal health policies have an impact on poverty reduction and food safety. They also enable countries that wish to export animals and products of animal origin to access regional and international markets from which they would otherwise be excluded because of the presence of animal diseases on their territory or because their Veterinary Services do not meet OIE standards.

For the above reasons, the work of the Veterinary Services is now recognised as a global public good. Rich countries also acknowledge that support for the Veterinary Services in developing and transition countries is a priority, not only to promote development around the world, but also to protect the world against the spread of animal diseases and zoonoses that had already been eradicated.

OIE's expertise is now at the core of national programmes intended for over one hundred Member Countries so as to help them strengthen their Veterinary Services and secure the planet against natural or intentional biological disasters.

1. Enhancing the monitoring of wildlife health threats to improve global surveillance, risk assessment and early warning to support One Health

In the past decade, 60% of emerging infectious disease events were caused by zoonoses and of those 72% of the pathogens involved were of wildlife origin. Land-use changes, expansion of livestock farming, and the competition for natural resources are bringing people, agricultural lands and livestock into closer contact with wild animals. This increased contact creates opportunities for the transmission of endemic and newly emerging infectious diseases between livestock, wildlife and humans. It is clear that there is a need to establish long-term, sustainable wildlife disease monitoring programs, nationally, regionally and globally, with a focus on understanding disease ecology and epidemiology among domestic animals, wild animals, and people. With the emergence and rapid spread of Severe Acute Respiratory Syndrome (SARS-2003), H5N1 highly pathogenic avian influenza (HPAI - 2003), it has become evident that a multidisciplinary approach is necessary to be strengthened and developed amongst a large variety of disciplines and stakeholders (e.g. wildlife biologists, veterinarians, and public health professionals). It is critical that environmental and wildlife elements be addressed when examining the epidemiology and emergence of already known pathogens behaving differently and new pathogens in wild animals, livestock and human populations to fully understand the drivers of these newly emerging infectious diseases to ultimately prevent or minimize the impacts on animal health and, where zoonosis are concerned, human health.

Wildlife disease outbreaks have often been underreported in the broader context of global epidemiology. Wildlife incidents are reported occasionally and without complete epidemiological information. More complete data that includes specific species affected, number of dead and sick animals, a precise geo-location, and any pertinent epidemiological and environmental information such as habitat, proximity to domestic farms, etc. would make the information more complete and provide necessary information that enables appropriate disease outbreak investigations and disease prevention and mitigation strategies

Obtaining information about wildlife events and integrating them into the GLEWS regular activities is the first step towards better disease intelligence and risk assessment at the animal/human/ecosystem interface that will improve early warning and support response when relevant.

FAO is encouraging the use of an unofficial wildlife morbidity and mortality events reporting system the Wildlife Health Event Reporter (WHER) which is linked to the FAO EMPRES-i system to increase global early warning capacities using wildlife disease surveillance information. If unofficial events reported through WHER meet GLEWS criteria, information will automatically be shared through the GLEWS platform and follow up activities, such as disease event validation, verification or activating response mechanisms, could take place as it currently occurs for unofficial livestock or public health events. Unofficial information collected through WHER, once validated, may be used by Members to feed their OIE reports.

OIE, as the World Organisation for Animal Health, through its World Animal Health Information System is improving disease information details provided for wildlife species for the official notification of OIE-listed diseases (WAHID) and runs the OIE Worldwide Monitoring System for Wild Animal Diseases (WAHIS-Wild Interface) for which countries may voluntarily notify OIE annually for approximately 50 wildlife infectious and non-infectious diseases. This information is available for concerned stakeholders and to the public in large.

WHO brings in the public health aspect of wildlife health monitoring and surveillance, be it directly from animals or via bush meat consumption. If there is an outbreak or risks for humans from wildlife disease events then WHO is intimately implicated in the assessment, prevention, preparedness, social mobilization and communication and when appropriate response. WHO also has official relationships with some of the prominent wildlife organizations because of the crucial human - wildlife health aspects.

An important next step of the GLEWS, is to contribute to an integrated «One Health» approach, by increasing communication among Ministries of Agriculture, Forestry/Environment and Public Health and others to be sure that professionals responsible for both unofficial and official reporting in respective countries, coordinate and communicate regularly.

It was decided by the GLEWS Management Committee in its meeting in Geneva in February 2011, that in the tripartite mechanism, wildlife activities should be strengthened recognizing that monitoring disease risks emerging at the wildlife-livestock-human interface is an increasingly important area. GLEWS, as part of its shared rumour and unofficial information and event tracking activities and disease intelligence mechanisms also will verify epidemiologically significant wildlife events systematically. Ultimately, this effort will improve the understanding of transmission, spread, and the epidemiological roles of wildlife and livestock at the animal-human-ecosystem interface, as well as clarifying when risk management interventions will have the greatest impact.

2. Schmallenberg Virus in Northern Europe: a new orthobunyavirus in cattle Situation Assessment

Note: Defra's International Disease Monitoring (IDM) team monitors outbreaks of high impact diseases around the world. The emergence of new vector borne diseases of cattle is monitored and reported when necessary.

Disease Report

Since the summer months of 2011, both the Netherlands and Germany have reported outbreaks of a disease in cattle, with clinical signs such as fever, reduced milk yield (up to 50%), inappetence, loss of condition and in some cases, diarrhoea. The clinical signs disappeared after a few days and frequency of reports ceased in the forthcoming months. In Germany, these reports were restricted to North Rhein Westphalia (European Commission, 2011). In Netherlands, there were more than 80 affected farms over the whole region. However, although the cattle recovered, there have now been reports of deformities in early stage calves and also in sheep in the Netherlands although there were no reports of similar clinical signs in sheep (Netherlands Ministry of Agriculture, 2011).

More than 100 samples from affected cattle on 14 farms in Germany were sent to the Friedrich Loeffler Institute, and initially were tested for Bluetongue, Epizootic 2 Haemorrhagic disease, Pestiviruses, Rift Valley Fever and others. All were ruled out. Further investigations could not isolate virus, but using novel techniques such as next generation sequencing and metagenomic analysis (Friedrich Loeffler Institute, 2011) of PCR products nine samples (9%) gave positive results for viral sequences. Of the samples from Netherlands, 18 out of 50 were positive (36%). Analysis revealed these viral sequences had strong similarity to the orthobunyaviruses. This group of viruses includes a subgroup of agents such as Akabane, Aino and Shamonda viruses. The subgroup (the Simu-serogroup) contains 25 different viruses, mainly affecting animals, causing mild clinical disease and transmitted by insect vectors. However infections of early stage foetuses can cause abortion or congenital disorders (European Commission, 2011). The new virus has been named Schmallenberg virus, for the town where initial reports of disease were made.

Situation Assessment

There are still uncertainties around this new virus, such as the vector responsible for transmission, the geographic distribution, transmissibility of infected animals and the origin. The virus has not been isolated, and as there is no serology test available at present, serological surveillance is not possible. Since the UK was made aware of the situation we have been carrying out scanning surveillance in cattle. No similar reports of clinical signs in the UK have been made. The more recent reports of the abortions and congenital deformities are of concern and heightened awareness in animal keepers is recommended over the coming months. This is because there is a low risk that inapparently infected cattle and sheep may have been imported during 2011 from the affected area. Such animals may have been exposed during early pregnancy with an increased risk of developmental abnormality. Typical deformities in lambs have included crooked necks, hydrocephalus and stiff joints. Most were born dead while infected live lambs did not survive. It may be too early to see the extent of problems in cattle and even in sheep, case rates are not known. Therefore animal keepers would need to be aware of lambs or calves born between now and Summer 2012 and report any abortions and deformities, which may be submitted for testing, particularly if from imported cattle or sheep. As infection may have occurred some time ago, it would be difficult to take disease control measures.

This is not a notifiable disease, and as such there are no trade restrictions in place or any current control measures. It is not possible to consider appropriate control measures until more is known about the route of infection and spread. According to the initial risk assessment carried out by the Netherlands RIVM, the risk to human health is considered very low (Netherlands Ministry of Agriculture, 2011). According to TRACES, the EU trade notification system, there have been 185 consignments of cattle from Netherlands, totalling nearly 3,000 animals and 51 from 3 Germany, of nearly 1,500 animals. Many of these animals will be in-calf heifers. For sheep trade, there have been 5 consignments of 38 sheep from Germany and 4 from Netherlands of 63 animals. Approximately half were females.

3. Highly Pathogenic Avian Influenza H5N1 in South East Asia

Update Situation Assessment

Note: Defra's International Disease Monitoring (IDM) team monitors outbreaks of high impact diseases around the world. Highly Pathogenic Avian Influenza (HPAI) is among those diseases of major concern.

Disease Report

In March 2011, Defra reported on the increase in outbreaks of HPAI H5N1 across East Asia which was attributed to clade 2.3.2 (Defra, 2011). The Food and Agriculture Organisation (FAO) has now reported that the increase due to a particular strain of this clade, H5N1 2.3.2.1, has spread in poultry and wild birds into South East Asia, including North Vietnam and posing a risk to other South East Asian countries (FAO, 2011). The FAO strongly advises increased preparedness and surveillance in this region.

Situation Assessment

South East Asia and neighbouring countries have, since 2003, seen waves of avian influenza spread around the region with one strain being replaced by others with time. It is generally accepted that while virus may be introduced into new areas by wild birds, it is poor biosecurity within the poultry industry itself which leads to the spread within regions. This new clade, H5N1 2.3.2 has emerged recently in poultry and wild birds, but it hasnot lead to significant increased spread to humans. By definition these viruses are extremely pathogenic to poultry and that has not changed. According to the FAO, HPAI-affected countries this year are Bangladesh, Cambodia, China [Hong Kong], Egypt, India, Indonesia, Israel, Japan, Republic of Korea, Mongolia, Myanmar, the Palestinian Autonomous Territories [West Bank], and Viet Nam. It should be noted that Israel and Palestine outbreaks were caused by a different clade, 2.2.1, more closely related to those found in Egypt. Six countries or regions, PR China, the Greater Mekong region in Vietnam, Indonesia, the Indian Ganges plain, Bangladesh and Egypt, are all now considered endemic for HPAI H5N1 in poultry (See map; FAO, 2011b).So far in 2011, 49 confirmed human cases of H5N1 HPAI have been reported to the World Health Organization (WHO), of whom 25 have died. In 2010, there were 24 deaths from 48 cases. Since 2003, deaths total 331 out of 565 cases (WHO, 2011). The European Centre for Disease Control (ECDC) has confirmed there is no change in risk to the human population from this new strain (Ian Brown; pers. comm.). In Europe, the last outbreaks were reported in 2010 in Romania and Bulgaria and were attributed to clade 2.3.2. This new strain (2.3.2.1) is typical of the drift mutation seen in HPAI H5N1 viruses and it will continue to be observed while the disease is relatively uncontrolled in South and East Asia. Wild Bird Migration risk to the UK: Previous risk assessments (Defra, 2008) and advice from the Ornithologists Expert Panel have concluded that the wild bird migration season which will start during the next month or so will bring wild birds to the UK from Northern Europe. While there remains a low risk that HPAI H5N1may be circulating in these populations, we would expect outbreaks in poultry or wild birds to be observed in Northern Europe before the UK. The European Commission supports a wild bird surveillance programme across the EU and the Community Reference Laboratory (AHVLA, Weybridge) has confirmed the ability to detect these strains of virus.

4. African Swine Fever in Russia

Update Outbreak Assessment

Note: Defra's International Disease Monitoring (IDM) monitors outbreaks of high impact diseases around the world. African Swine Fever (ASF) is among those diseases of major concern.

Disease Report

The Russian Authorities have reported to the OIE three new outbreaks of African Swine Fever (OIE, 2011; see map below). These new outbreaks are distributed throughout western Russia. The first in Krasnodar is in the Caucasus region in backyard pigs. The second in Murmansk in northern Russia is approximately 220 km from the border with Finland and 120 km from the border with Norway again on a backyard farm. The third outbreak in Arkhangel region was also in backyard pigs.

Situation Assessment

Two of the latest outbreaks, outside the Caucasus region, are the first reports of ASF in these regions indicating another «jump» such as those to St. Petersburg region in January and March 2011 (see previous Defra reports, http://www.defra.gov.uk/foodfarm/farmanimal/diseases/monitoring/poa.htm). The latest two outbreaks occurring in Northern Russia are in areas with very small pig 2 populations (<1 animal per sqkm; Empres Watch, 2010) and will therefore impact little on the pig producing sector. It is interesting that in all the recent jumps, the disease has occurred in backyard pigs. This sector of the pig industry in Russia still uses swill feeding. These premises may be connected epidemiologically, but there has been no indication of this in the reports. Alternatively there may be wider infection of pig feed (swill or otherwise) orthere may be contact with infected wild boar across the whole region. It is considered

less likely that the disease has spread through movement of live domestic pigs. The Russian Federation (RF) veterinary authorities have stated that the spread of ASF in the southern half of the country is out of control (FAO, 2011). Sporadic outbreaks in other areas will require coordinated action for control within the RF as a whole and EU veterinary expertise in good quality diagnostics could be used if necessary.

5. Foot and Mouth Disease in Cattle in Paraguay

Preliminary Outbreak Assessment

Note: Defra's International Disease Monitoring (IDM) team monitors outbreaks of high impact diseases around the world. Foot and Mouth Disease (FMD) is considered one such high impact disease.

Disease Report

Paraguay has reported an outbreak of Foot and Mouth Disease (FMD) type O in San Pedro region in cattle (European Commission, 2011; OIE, 2011; see map below). The thirteen affected animals were from a herd of over 800 cattle and were all under 24 months of age. Disease control measures are in place including stamping out and vaccination.

Situation Assessment

The last outbreak of FMD in Paraguay was in 2003, when FMD O was also recorded. Ecuador reported FMD O (topotype EURO-SA) in 2010, so it will be interesting to see if there is any similarity between these outbreaks and what vaccine matching results indicate as the Ecuador strain did not match O Campos vaccine (World Reference Laboratory, 2011). Since 2006, Paraguay, Argentina, Brazil and Bolivia had in place a 15km high intensity surveillance zone along their joint borders to ensure the FMD free with vaccination status of the rest of the countries (see map 2 below). Within this zone all animals were identified, movements controlled of live animals and products and all susceptible animals were vaccinated. The region of the current outbreak is outside these areas.

Schematic representation of the region directly involved in joint actions of the border area. (From: Panaftosa, 2009).

In February 2011 these high intensity surveillance zones were lifted by the OIE and the whole country (over 12 million cattle) became «free with vaccination» status. The country of Paraguay was approved for the export to the EU of deboned and matured beef from vaccinated cattle from the country, albeit currently with the exception of the high intensity surveillance zone, according to Commission Regulation EC No. 206/2010. For the near future, the Paraguay authorities will not be able to sign export certificates for fresh bovine meat destined for the EU (European Commission, 2011). According to TRACES, the EU trade notification system, since 1st August, there has been one consignment of bovine and equine products (untreated bristle or hair, not for human consumption, which is considered a very low risk animal by-product) and one large (>11,000 kgs) consignment of deboned bovine meat, which is due to arrive by ship in October (see map for location of cutting plant). The consignment of meat will be targeted for checks at the Border Inspection Post when it arrives, the extent of which will depend upon information from the Competent Authorities in Paraguay and the European Commission. The consignment of untreated bristle was checked on entry and found to be compliant.

Conclusions

There would be a negligible risk of introduction via infected vectors at this time of year. It is difficult to quantify the risk of introduction of disease into the UK through imports of pregnant animals as little is currently known of the disease epidemiology. The risk of spread is difficult to quantify until the full epidemiological characteristics of the disease are known. Vector borne transmission to be negligible at the current time of year, as the UK would be considered vector free.

The FAO has quite correctly highlighted the issue of HPAI H5N1 across South and East Asia, where the disease continues to cause significant problems for the poultry industry. In terms of the risk to the UK, these outbreaks do not significantly increase 3 our currently constant low level of risk of disease introduction to the UK and EU poultry population through contact with wild birds. It remains important for the poultry industry therefore to maintain high standards of biosecurity, reduce level of contact with wild birds and report disease suspicion promptly.

An EU Member State with a high proportion of backyard pig farms, wild boar contact, suitable vector (Argasid tick) populations or practicing swill feeding would be considered to be at greater risk than the EU MSs with mainly high biosecurity commercial pig farms (such as the UK). Nevertheless, it is important that all EU MSs recognise there may be a future need for harmonising activities for controlling ASF across the whole region and that regular exchange of information and expertise is very important. The risk of introduction by legal trade in susceptible livestock or products is negligible as EU rules prohibit imports of such trade from Russia. There could be an increased risk of infection present in pig meat and pig products in Russia. It is therefore important to uphold the ban on swill feeding, to ensure adequate cleansing and disinfection of vehicles returning from infected regions and safe disposal of catering waste. Importing meat or meat products (including ham, salami, sausages and other delicacies) from Russia as personal imports is illegal.

This outbreak does not increase the continual low level of risk of introduction for Foot and Mouth Disease into the EU from any affected the area. There is a relatively low 3 volume of trade from Paraguay and the animals destined for deboned and matured meat must be clinically examined ante and post mortem, reducing the risk. The European Commission has also requested Border Inspection Posts to be vigilant for further consignments of fresh meat from Paraguay.

References

1. European Commission (2011) New orthobunyavirus detected in cattle in Germany.http://ec.europa.eu/food/committees/regulatory/scfcah/animal_health/presentations/06122011_new_orthobunyavirus_in_cattle_germany.pdf Accessed 12/12/2011.

2. Friedrich Loeffler Institute (2011) New orthobunyavirus detected in cattle in Germany. Accessed 12/12/2011.

3. Netherlands Ministry of Agriculture (2011) Letter on the background and current developments of Schmallenberg virus in the Netherlands. Accessed 20/12/2011.

4. Defra (2011) Update on HPAI (H5N1) in East Asia, January - February 2011.http://archive.defra.gov.uk/foodfarm/farmanimal/diseases/monitoring/documents/hpai-east-asia-110304.pdf Accessed 31/08/2011.

5. Defra (2008) Highly Pathogenic Avian Influenza - H5N1. Recent Development in the EU and the likelihood of the introduction into Great Britain by wild birds. http://archive.defra.gov.uk/foodfarm/farmanimal/diseases/monitoring/documents/qra-h5n1-wildbirds081029.pdf Accessed 31/08/2011.

6. FAO (2011) Bird flu rears its head again. Increased preparedness and surveillance urged against variant strain http://www.fao.org/news/story/en/item/87196/icode/Accessed 30/08/2011.

7. FAO (2011b) Approaches to controlling, preventing and eliminating H5N1 Highly Pathogenic Avian Influenza in endemic countries. http://www.fao.org/docrep/014/i2150e/i2150e.pdf Accessed 31/08/2011.

8. WHO (2011) Cumulative number of confirmed human cases of avian influenza A/(H5N1) reported to WHO. http://www.who.int/csr/disease/avian_influenza/country/cases_table_2011_08_19/en/index.html Accessed 31/08/2011.

9. Empres Watch (2010) FAO takes a close look at the pig Sector in Eastern Europe to better understand the threats of African Swine Fever.http://www.fao.org/docrep/012/ak755e/ak755e00.pdf Accessed 11/04/2011.

10. FAO (2011) African Swine fever in Eastern Europe: disease dynamics and collaborations.http://www.fao.org/ag/againfo/programmes/en/empres/news_160211.html Accessed 11/04/2011.

11. OIE (2011) African Swine Fever in Russia. Follow-Up Report No. 54 Ref OIE 10465; Report Date 08/04/2011.http://web.oie.int/wahis/reports/en_fup_0000010465_20110408_163248.pdf Accessed 11/04/2011.

12. European Commission (2011) Paraguay: outbreak of foot and mouth disease. Urgent Fax - 20/09/2011. Received 20/09/2011.

13. OIE (2011) Foot and Mouth Disease in Paraguay. Immediate Notification report. Ref OIE 11022 Report Date 18/09/2011 Accessed 19/09/2011.

14. Panaftosa (2009) Situation of the eradication programmes for foot and mouth disease. South America, 2009. Accessed 19/09/2011.

15. World Reference Laboratory (2011) WRLFMD Quarterly Report January - March 2011. Accessed 20/09/2011.

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