Immunity Deficiency In Birds And Neonicotinoid Pesticides
This feature is a continuation of an article by Dr Rosemary Mason and Palle Uhd Jepsen. Read further or Go to beginning of the feature.
Greenfinches in the UK and Europe
In the UK,
greenfinch deaths (maximum number of deaths in the months August to
October) from infections with Trichomonas gallinae, a protozoal organism
which invades the bird’s crop and mucosal lining of the beak, started
around 2005 and has devastated the populations throughout Europe [52].
Apparently, the organism can survive only a matter of minutes outside
its host, so if it were spread conventionally it would require direct
contact between birds.
In August 2009 there were reports of tens of thousands of songbirds, mostly greenfinches, dying in the west of Germany and the deaths spread across the border into the eastern Netherlands [53].
According to Hugh Jansman of Wageningen University, “The canker disease was first described as early as 1500, but was not found in wild songbirds until 2002.”
It had been well known as a cause of disease in pigeons and doves, and birds of prey that fed on them, but had never been seen before in songbirds.
By 2010, the population of
greenfinches in central England had decreased by one third [54] and in
March 2011, greenfinches, chaffinches and goldfinches are continuing to
die from the disease [55].
Chaffinches in the UK and Europe
In
the UK, reports of chaffinches appearing in gardens with white, crusty
growths on their legs and feet caused by a papilloma virus began in
2005; the mortality is said to be about 20%, so the disease kills more
slowly than with the greenfinch Trichomonas infections [52].
In 2004, two dead chaffinches were found in Europe, one of which was suffering from two diseases. In the Czech journal, pathologists reported one as having a co-infection between papilloma virus (which was also affecting the beak) and K. jamaicenis, a mite [56].
They also commented that “beak
papillomatosis is rare in wild birds”.
The Tit Family in the UK
In 2005, acute necrotising pneumonitis with Suttonella ornithocola spp. in the tit family was first reported by researchers in Inverness and the Institute of Zoology (IoZ), London; they found that the gram negative bacterium recovered from the diseased birds represented a novel species [57].
In 2006 there were further reports of mortality from this novel bacterium [58]. In 2010, pathological studies on further cases in tit species were reported in the Veterinary Journal, by Lawson et al. from the IoZ [59].
In a surveillance of garden bird mortality, S. ornithocola
was isolated from the lungs of six tits from a total of 82.
Avian pox in Great Tits
The
first case was reported in the UK in 2006. Although there had been
previously isolated reports in other birds, Great Tits seemed to be
affected more severely, with warty tumour-like growths around the eyes
and beak, sometimes interfering with feeding.
Tumours on the body can
grow quite large. The virus is spread by biting insects and is
persistent in the environment.
It was first reported in south-eastern counties, Surrey, Sussex and Kent; from there it has spread north and westwards, so that it was first found in Wytham Woods in the Edward Grey Institute near Oxford. Prof. Ben Sheldon, Director of the Institute, said records had been kept there since 1947 and they first detected the disease in 2010.
Oxford University are undertaking molecular analysis to see if it is a new strain, or one from Europe. Prior to 2006 it had been reported in Austria, Czech Republic, Slovakia and Scandinavia [60].
Tropical Usutu Virus in Blackbirds
In
September 2011, mass deaths of blackbirds were reported in the
Rhine-Neckar area of Germany. The Bernhard-Noct Institute for Tropical
Diseases and the Friedrich-Loeffler Institute, examined four birds and
confirmed that it was the tropical Usutu Virus from Africa.
It was first
seen in Austria in 2001, then Italy, Hungary and Switzerland. In
blackbirds it causes apathy then signs of a central nervous system
disorder, with unnatural movements of the head [61].
Continues....
environmental impact and impact on human health.