It is estimated that 75% of pathogens are zoonotic, and overall, zoonotic pathogens are twice as likely to be associated with emerging diseases than non-zoonotic pathogens (Taylor, M et al. 2001). Kangaroos are harvested as game meat, with the product also sometimes termed ‘wild-game meat’. It is well recognised that game meats frequently cause illness in consumers, especially when care has not been taken while eviscerating and handling the carcasses (Alwynelle 2006).
The European Union has recognised the potential dangers of game meats, with the European Council issuing a Directive on the killing of wild game and the placing of wild-game meat on the market. This Directive stipulates that wild-game meat imported from countries outside the European Union should be subject to the minimum requirements laid down by this Directive for trade between Member States (Office for Official Publications of the European Communities 1992).
This report shows that the hygiene standards surrounding the production of kangaroo meat do not presently meet the Australian nor the European standards. Further, the scale of the kangaroo industry and slaughter process used will most likely preclude the kangaroo industry from meeting these standards in the future. This report describes some of the known kangaroo meat-related pathogens and diseases and highlights the lack of hygiene regulation inherent in the processing of kangaroo meat for human consumption.
At the time of writing there was a six month ban on the import of kangaroo meat to the Russian Federation as a result of abnormal coliform bacteria accumulations (Bardon 2008). Abnormal coliform bacteria accumulations are a commonly-used indicator of poor sanitary quality in food and water (Spellman 2003). In independently assessed samples (Silliker 2008) obtained by Animal Liberation NSW from biopsies performed on carcasses located in remote kangaroo chillers in Queensland the levels of generic Escherichia coli were so high (Table 1) that they warranted Australian Quarantine and Inspection Service (AQIS) alerts known as “E.coli ALERTs” (Australian Quarantine and Inspection Service 2008).
Diseases in kangaroos
Dr David Obendorf is an Australian wildlife veterinary pathologist and a member of the Scientific Advisory Board to the International Animal Health Body, Paris (Office des Internationale Epizooties), with 20 years’ experience in the parasites and diseases of Australian fauna. He has noted that “[k]angaroos … can harbour a wide range of parasitic bacterial, fungal and viral diseases” (Obendorf 2001). Some of the diseases which have been documented affect only kangaroos and so reduce harvest capacity. Others can affect humans as well and so raise serious public health concerns. The following examples illustrate the magnitude and extent of disease outbreaks among kangaroo populations.
Epidemics and viruses
A number of epidemics have been reported in wild kangaroos. The most worrying in relation to human health-risk is an undiagnosed fatal epidemic. There have been several reported incidents of sporadic “die-offs” in large kangaroo populations in central and western Queensland and north western New South Wales dating back to the 1950’s. The following common characteristics are reported in an internal report (Speare, Johnson et al. 1991):
1) Epidemics appear to occur within the Winton - Longreach - Charleville area about every 2-10 years;
2) The epidemics are associated with heavy rain or flooding;
3) Deaths occur over a 1-2 week period;
4) Between 25-80% of the populations in affected areas are impacted;
5) Red Kangaroos and Eastern Wallaroos are mostly affected, although mortalities have also been reported in Eastern Grey Kangaroos;
6) Clinical signs are those of the central nervous system disease;
7) There is no obvious gross pathology;
8) Sheep are not affected.
There are few detailed accounts of this pathogen. In 1983 there was a dramatic population crash which affected Red Kangaroos, Eastern Grey Kangaroos and Common Wallaroos in the Boulia - Bedourie - Windorah area of western Queensland. Deaths were reported to begin in some areas before drought-breaking rains and several months later in other areas (Speare, Donovan et al. 1989). In October 1988, a major epidemic of the unknown disease broke out among kangaroo populations in north-western New South Wales. The disease had a sudden onset, a short duration of about two weeks and a high death rate. Most of the animals infected with the disease died; those who survived had difficulty rising and a reduction in motor function. Mature kangaroos were affected more frequently than young individuals. The disease had drastic effects on the population in the five affected areas, with an average decline of 42% in Red Kangaroos (although one area recorded a decline of 72%) and a 46% decline in Grey Kangaroos (Curran 1999). Similar epidemics occurred in Queensland in 1990 (Speare, Johnson et al. 1991) and 1999 (Curran 1999).
The 1990 epidemic followed heavy rain and flooding in the Thompson - Barcoo -Cooper river system in western Queensland (Clancy, Southwell et al. 1990). There were significant mortalities of Red Kangaroos, Eastern Grey Kangaroos and Wallaroos, with mortality rates declining away from the river. Aerial surveys suggested a reduction in the Red Kangaroo population of more than 60% in an area of 10,000 km2. The mortalities coincided with outbreaks of sandflies, Austrosimulium pestilens, and necropsies on carcasses suggested arbovirus infection (Speare, Johnson et al. 1990).
During the 1990 epidemic specimens of Wallaroos and Red Kangaroos were collected from two separate locations and autopsied to determine the nature of the pathogen. All the kangaroos had a mild to acute mononuclear meningoencephalitis and interstitial pneumonitis (Lundie-Jenkins 1999). The Queensland Parks and Wildlife Service report (Lundie-Jenkins 1999) goes on to state the obvious:
“There is a need to conduct more detailed investigations into the sporadic die-offs in large kangaroo populations specifically in relation to: the dynamics of populations of large kangaroos, the potential transmission of disease agents to livestock and humans and potential human health concerns associated with the harvesting and consumption of kangaroo meat.”
Alarmingly, this virus has yet to be identified. The drastic impact it has on dense kangaroo populations raises grave concerns for the possible impact on humans. The scale of the kangaroo industry and its potential impact on human health mandates a full understanding of the various pathogens that affect harvested kangaroos and their potential link to human health – not a wait and see approach.
There a number of other known epidemics. Apparent epidemics of ‘lumpy jaw’, a condition of jaw infection, have occurred in the Murchison area of Western Australia several times this century (Tomlinson and Gooding 1954). Localised epidemics of coccidiosis, single-celled protozoan parasites that are more complex than either bacteria or viruses, resulted in the deaths of many juvenile Eastern Grey Kangaroos trapped by rising flood waters (Barker, Harrigan et al. 1972). Malnutrition and high densities were thought to make younger animals particularly susceptible when exposed to large numbers of oocysts (egg cells). Another epidemic produced widespread blindness. This outbreak affected thousands of Western Grey Kangaroos between April and July 1994 and March and June 1995 in western New South Wales, South Australia, north-western Victoria and between December 1995 and April 1996 in Western Australia. Eastern Grey Kangaroos, Red Kangaroos and Wallaroos were also affected, but to a lesser extent (Hooper, Lunt et al. 1999; Reddacliffe 1999). It is believed that the outbreaks were caused by a virus (possibly the Wallal virus) spread by insects, but the factors which lead to the epidemic are unknown (Hooper, Lunt et al. 1999).
Further, a survey in coastal central Queensland found that 24 out of a sample of 70 Eastern Grey Kangaroos carried antibodies for Ross River Virus, and 36 had antibodies for Barmah Forest Virus (Frances, Cooper et al. 2004). Antibodies to the Trubanam Virus were found in 21.1% of Western Grey Kangaroos sampled in Western Australia (Johansen, Mackenzie et al. 2005).
Toxoplasmosis and salmonellosis are two bacterial infections that affect kangaroos and which also have significant public health implications. The infections can spread to humans through the handling, processing or consumption of infected kangaroo meat - and as many as one in two kangaroo carcasses may harbour the salmonella bacterium (Shultz, Hough et al. 1996). A recent food-borne outbreak of toxoplasmosis in Queensland caused acute clinical illnesses in 12 people and one case of congenital chorio-retinitis (inflammation of the eye tissue) in a newborn baby. Contaminated kangaroo meat was the most likely cause of the outbreak (Obendorf 2004).
A single Western (Macropus fuliginosus) or Eastern (M.giganteus) Grey Kangaroo, for example, can be infected with up to 30,000 nematodes (parasitic worms) from up to 20 different nematode species (Speare, Donovan et al. 1989). In southern Queensland Pelecitus roemeri, a large nematode worm, infects on average 18% of M. giganteus, 6% of M. rufus (Red Kangaroo) and 22% of M. robustus (Eastern Wallaroo). The following occurrences of pathogens in kangaroos were cited in an independent report prepared for the Kangaroo Management Advisory Panel (Olsen and Low 2006):
1) The cyst-forming tapeworm Echinococcus granulosus entered Australia on sheep and now infects kangaroos as intermediate hosts, in severe cases killing the host (Johnson, Spear et al. 1998), or rendering it more susceptible to predation by forming debilitating cysts in the lungs (Jenkins and Macpherson 2003);
2) Cutaneous leishmaniasis, a disease affecting both humans and wildlife mostly outside of Australia, was found in Red Kangaroos held in captivity near Darwin (Rose, Curtis et al. 2004);
3) Cryptospodium oocysts, a protozoan parasite that can cause diarrhoea in humans and other mammals, was found in the faeces of Eastern Grey Kangaroos (Davies, Kaucner et al. 2003; Power, Slade et al. 2004); and
4) a serious blood infection by the nematode Pelecitus roemeri was recorded in a captive Western Grey Kangaroo (Portas, Spratt et al. 2005).
Point of kill
For the kangaroo industry the challenges of disease control and hygiene regulation are exacerbated by the scale of the industry, the remote locations where harvesting takes place, and the conditions under which harvesting occurs.
In theory, kangaroo shooters operate under strict guidelines which exist to prevent the harvesting of unhealthy individuals. The Australian Standard for Hygienic Production of Game Meat for Human Consumption stipulates that kangaroo shooters must carry out pre-death inspections of target movement to determine whether there is any indication of sickness (CSIRO 2007). According to the Standard, no animal should be harvested if it can be seen that it:
1) has an abnormal gait;
2) is weak or lethargic;
3) lacks alertness;
4) sits in an unusual way;
5) holds its head at an unusual angle;
6) has any discharge from the nose or mouth;
7) has any skin abnormalities; and/or
8) is poorly fleshed, or is otherwise apparently injured or suffering from an abnormality that may render meat derived from it unwholesome.
However, in practice it is difficult to comply with the Standard. Inspections are impossible to carry out because the harvesting of kangaroos occurs at night and in remote locations. Further, the shooting of a kangaroo requires that it must first be transfixed (made to stand still) making any observation of target movement impossible by a spotlight (Sibraa 2004). The result is that such inspections by shooters are of little value in identifying diseased individuals.
Visual meat inspection procedures following harvesting and processing are also far from effective. Unless gross lesions are apparent in the meat or samples are taken for testing, some infections are difficult or impossible to detect (Sibraa 2004). If the animal is ill and the meat becomes fevered after death the dark colouring of kangaroo meat further reduces any chance of picking up on any visual indications of the condition (Obendorf 2001).
In a response to the ban by the Russian Federation on kangaroo meat imports AQIS has issued updated guidelines for microbiological testing of game carcasses. The guidelines require that one in every 600 carcasses be tested for E. coli (Australian Quarantine and Inspection Service 2008). As the section on ‘Remote chillers’ will show, this frequency of testing is not nearly enough to ensure that contaminated carcasses are not processed and sold for human consumption.
As well as the problems associated with the shooting of unhealthy individuals, further risks of bacterial infection arise due to the sometimes excessive periods of time between an animal being shot and processed and the carcass being placed in cold storage. Shooters often travel long distances for their night’s kill and in summer there are few hours of darkness. Kangaroos are gutted and bled in the field and then hung on an open air truck (DVD: Chapter 9) for the duration of the night (CSIRO 2007). The resulting long delay between processing (in the field) and cold storing increases the likelihood of bacterial contamination.
There has been and continues to be minimal supervision to ensure that meat submitted after the arbitrary time limit of two hours of daylight is rejected (Obendorf 2001; Administrative Appeals Tribunal 2008).
Remote chillers (Figure 1) are used to store kangaroo carcasses at field depots (unlike livestock, kangaroos are shot remotely and not killed at abattoirs). In theory, premises and equipment at the field depot should not be a source of contamination of wild game material; they should facilitate hygienic production, and should be effectively inspected and monitored (CSIRO 2007). However, evidence collected by Animal Liberation NSW (Appendix 1, Sibraa 2009) from various remote chillers in NSW and Queensland suggests that chillers are often unhygienic and use a range of practices which violate both the National Code of Practice for the Humane Shooting of Kangaroos and Wallabies for Commercial Purposes (Department of the Environment Water Heritage and the Arts 2008) and the Australian Standard for the Hygienic Production of Game Meat for Human Consumption (CSIRO 2007). This evidence documented such practices as:
1) hanging carcasses touching the floor (DVD: Chapter 1);
2) fresh blood on the floor (DVD: Chapter 2);
3) old dried blood that had not been washed away on the floor (DVD: Chapter 3);
4) carcasses over-packed and touching one another (DVD: Chapter 4);
5) no sterile zone due to only one point of entry into the chillers (DVD: Chapter 5);
6) tags on carcasses showing that they are 12 and 13 days old (DVD: Chapter 6); and
7) implement used for bludgeoning joeys (young kangaroos) with caked blood on the end (DVD: Chapter 8).
(Note: copies of the video recordings documenting the above practices are available on DVD as an accompaniment to this report. If you have not received a copy of this DVD and wish to view this material, please contact Animal Liberation NSW.)
Microbial testing of meat samples (DVD: Chapter 10) obtained from these chillers following AQIS guidelines (Australian Quarantine and Inspection Service 2008) found generic E. coli levels greater than 500 colony forming units per cm2 (cfu/cm2) in five of ten carcasses obtained from two separate chillers in the vicinity of Charleville (7 December 2008) and Mitchell (8 December 2008) in Queensland (Table 1). The sampled chillers were located over 300 km apart, indicating that samples were independent and that the problem is regional. An E. coli level of 500 cfu/cm2 is deemed unacceptable and enough to initiate an AQIS “E. coli ALERT”. If only one carcass is found with this level of E. coli then all the carcasses in the same batch (a batch is 15 carcasses as defined by AQIS) are to be dismissed (Australian Quarantine and Inspection Service 2008). Thus a sampling rate of one in 600 carcasses, as specified by AQIS (Australian Quarantine and Inspection Service 2008), can easily overlook many carcasses not fit for human consumption and import.
There is a history of chillers in unhygienic conditions and the phenomenon seems to be widespread. During a South Australian Kangaroo Management Program public meeting Eddie Anndriessen, an AQIS meat inspector, stated that in a follow-up inspection of 15 chillers throughout South Australia which took place two years after the initial inspection, he found:
“not a single chiller box (Macro Meats and other processors SA, sic) that is up to standard, with most being unclean or uncleanable; a big incidence of fly-struck meat is going down to Adelaide; airflow floors are not being cleaned thoroughly; there's still congealed blood and muck; most of the dirty water is washed out from the front with the bones, instead of being plumbed to a drain; no connection to potable water, only one chiller box had chemicals for cleaning; and that there were still kangaroo feet in the surrounds from two years ago” (The South Australian Kangaroo Management Program 1998).
Kangaroo chillers are numerous and scattered throughout remote areas. The hygiene issues exposed thus far are likely to be prevalent, as hygiene in remote areas is difficult to monitor and almost impossible to regulate.
There is a concern raised regarding the potential human health threat from an unidentified epidemic that periodically causes high levels of mortality in localised kangaroo populations. The most obvious causes of contamination of any kind of meat product with common bacteria such as Salmonella, E. coli, and Campylobacter which can pose threats to human health (Sibraa 2004) are:
1) delays in gutting carcasses;
2) delays in refrigerating carcasses;
3) inappropriate sanitation and effluent management;
4) the inadequate long-term chilling of carcasses; and
5) failure to use potable water during or after gutting in the field.
Australia has rigid and extensive meat hygiene standards for the processing of game meat and domestic stock as well as demanding export standards. Under these standards, the point of slaughter for domestic meats is limited to processing plants which are tightly regulated. In contrast, there are millions of points of slaughter for kangaroos in the outback - as many as there are kangaroos killed. There are also hundreds of intermediate processing and holding field depots (remote chillers) throughout the kangaroo harvesting states (Queensland, New South Wales, South Australia and Western Australia). Effectively, the conditions in which kangaroo harvesting and processing takes place create a double standard for the kangaroo industry which claims to adhere to Australian hygiene guidelines but which cannot possibly regulate all individual points of slaughter or remote chillers.
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