cases, have been from Western Australia, with a further thirteen cases from the Northern Territory. It is also interesting to note that the first confirmed case of encephalitis due to Kunjin virus occurred in Western Australia in 1978, and three additional cases have been diagnosed since, two from Western Australia in 1991 and 1995, and one in Victoria in 1984 (Table 8.1). Most of the cases of Australian encephalitis in Western Australia have occurred in areas distant from the Ord River irrigation area. Of particular significance was the spread of MVE virus from the Kimberley area south to the Pilbara and Gascoyne regions causing one case of encephalitis in 1978 and three cases in 1981. It is hypothesized that movement of virus to the Pilbara region in 1978 was due to an increase in viral activity in the West Kimberley area following heavy rainfall and flooding, and that with subsequent extensive cyclonic rainfall in the Pilbara region, viraemic waterbirds moved south down the narrow coastal strip, introducing the virus into Pilbara (Stanley 1979). It is probable that a similar mechanism may have occurred in 1981. Although there has been evidence (see next section), of MVE virus activity in the Pilbara region in recent years, there have been no further cases. Analysis of the cases of Australian encephalitis has indicated that Aboriginal infants, particularly male infants, are most at risk of fatal or severe disease (Mackenzie et al. 1993a). However, tourists and visitors to the Kimberley region (and Northern Territory) have also been shown to have an increased risk of disease. Sentinel chicken surveillance Following the 1978 outbreak of Australian encephalitis, a number of sentinel chicken flocks were established in the Kimberley area. Six flocks had been established by 1981 and the number rose to twenty-four flocks in twenty-two regional centres in the Kimberley, Pilbara and Gascoyne regions by 1989 (Broom et al. 1989; Mackenzie et al. 1992; 1994c). Each flock contains twelve chickens which are bled at two weekly intervals between November and June, the period of increased risk of virus transmission, and monthly at other times. The sera are then assayed for antibody to MVE and Kunjin viruses in our laboratory in Perth to provide an early warning system of increased virus activity. Initially sera were tested by HI for the presence of antibody, and positive sera were then subjected to neutralization assay to determine the identity of the infecting virus. A more rapid enzyme-linked immunosorbent assay (ELISA) was introduced in 1986 (Broom et al. 1987), and more recently a competitive ELISA using specific monoclonal antibodies to identify the virus is being used (Hall et al. 1992; 1995). Sentinel chicken flocks were also established in 1992 in the Northern Territory to monitor MVE activity (Aldred et al. 1992). The sentinel chicken programme has clearly shown that MVE virus is enzootic in several areas of the Kimberley region, particularly in the Ord River area at Kununurra. Seroconversions in sentinel chickens occur every year during the latter half of the wet season. Water Resources. CRC Press. 1998-12-17: 131–131. ISBN 978-0-429-21654-1.
Tornos, Fernando; Locutura, Juan; Martins, Luis. The Iberian Pyrite Belt Field trip guide(PDF). Joint SGA IAGOD International Meeting. 28 August – 3 September 1999. （原始内容(PDF)存档于15 August 2011）.
Tornos, Fernando; Locutura, Juan; Martins, Luis. The Iberian Pyrite Belt Field trip guide(PDF). Joint SGA IAGOD International Meeting. 28 August – 3 September 1999. （原始内容(PDF)存档于15 August 2011）.
