Welcome to the last issue for 2012. We wish you, your staff and families a happy and safe holiday period and a prosperous 2013. We encourage your inputs and comments.
Wild pigs and emergency animal diseases
One of the common questions posed by farmers is what potential risk do wild pigs present in spreading important diseases exotic to Australia?
A recent article by Cowled et al has attempted to provide some answers by modelling the spread of classical swine fever in wild pig populations in northern Australia. They found that epidemics could be controlled by culling or vaccination and that it may be necessary to cull or vaccinate only relatively small proportions of the population to successfully contain or eradicate an epidemic. It is important that the spatial structure, ecology and behaviour of wild populations are taken into account.
Bluetongue virus serotype 14 (BTV-14)
In September 2011 cattle imported to Russia from Germany via Poland and Belarus were found to be positive on serology and PCR for bluetongue. In December 2011 Russia advised the OIE that there was evidence of local circulation of BTV-14. No evidence of disease was reported. Subsequent testing in Poland and Latvia confirmed the BTV-14 virus was virtually identical to that found in attenuated vaccines manufactured in South Africa. Similar findings were reported from Spain and Lithuania. Read further information.
The South African vaccine is not registered for use in Europe. It appears the attenuated vaccine strain was being spread by local vectors following unauthorised vaccine use. In 2008 BTV-6 was detected in Germany and Netherlands and BTV-11 in Belgium. These detections were likely the result of unauthorised vaccine use. They demonstrate the need for care in the use of attenuated vaccines.
Novel Australian viruses
In 2010 domestic Muscovy ducks on Kangaroo Island were reported to be lethargic, have diarrhoea and a high mortality rate. Salmonella was isolated from the ducks. Subsequent investigations resulted in the isolation of an orthomyxovirus which has been named Cygnet River virus. This virus may be pathogenic, either alone or in concert with other infections. Read an article with further information.
Researchers from Australia, Florida and Germany have isolated a paramyxovirus from Australian pythons suffering from a neuro-respiratory disease. It has been dubbed the Sunshine virus, after the Sunshine coast where the pythons were found. For further information link to this article.
Researchers have reported the isolation of a novel paramyxovirus from pteropid bats. The virus, named Cedar virus, shares features with the henipaviruses (Nipah and Hendra viruses). It has not been associated with any disease at present. For further reading download this article.
Haemorrhagic fevers in humans
In August 2012 an outbreak of Ebola haemorrhagic fever (EHF) in north eastern Democratic Republic of Congo resulted in 62 cases and 34 deaths. In November 2012 two outbreaks of EHF in Central Uganda and in the Kibaale region resulted in a number of deaths. In November 2012 an outbreak of Marburg virus in Uganda resulted in 9 deaths.
A recent report on the serological screening of healthy, wild caught orangutans on Kalimantan Island in 2005-2006 has revealed that 18.4% and 1.7% were seropositive for Ebola and Marburg viruses respectively. The Ebola positive sera showed specificity to the African viruses not the Ebola Reston strain found in primates and domestic pigs in the Philippines. This work indicated the need for further investigations to determine the importance of these findings and to determine a reservoir host if possible. Read additional information.
Canadian researchers recently demonstrated that Ebola virus could possibly be passed from infected pigs to primates via the air. Previously it was believed the virus was transmitted by contact with blood or other bodily fluids. However transmission between primates in similar housing was not demonstrated. Further work is required to establish the importance of this finding. View further information.
Severe respiratory disease has been reported in 9 human cases in Qatar, Jordan and Saudi Arabia. Five have died. Two small clusters indicate either a common source or human to human transmission. Isolates of the virus indicate it belongs to a clade of the Betacoronaviruses found in Asiatic bats. Read additional information. Unlike the SARS virus, this virus has the ability in the lab to infect cell lines from many different species. The reservoir host is yet to be identified.
Wobbly possum disease - NZ
A novel virus has been proposed as the cause of wobbly possum disease. Affected possums lack coordination, have head tremors, blindness and feed during the day. The possums become weak and die. For further information, view this website.
New Zealand authorities are concerned that people are moving affected possums to other areas in an attempt to control this pest animal. This may also result in the dissemination of bovine TB, which the possums may be carrying.
Earlier in 2012 there were reports of an increased death rate in domestic dogs in Switzerland due to infection with Angiostrongylus vasorum (also known as French heartworm). This has been associated with an increase in the fox population, which is believed to be the reservoir host, with snails as the intermediate host. Angiostrongylus vasorum has been reported from most European countries, Africa, South America and Canada. (ProMED report) Indications are this parasite is extending its range and practitioners should be alert.
Work being undertaken by a postgraduate student at the University of Tasmania on the ecosystem consequences of devil facial tumour disease has correlated a rise in feral cat numbers with a decline in devil numbers and a subsequent increased risk of toxoplasmosis infection in both domestic and native species. High levels of infection were reported in eastern quolls, pademelons and wallabies. (ProMED report)
Brucella - Argentina
Eight workers at an animal shelter in Tierra del Fuego province, Argentina were reported to be suffering from brucellosis (ProMED report). This is a timely reminder of the need for biosecurity precautions to protect yourselves, your families and employees from zoonoses. Do you have a copy of the Guidelines for Veterinary Personal Biosecurity recently released by the AVA? Does your practice have a written infection control plan which is exercised?
New diseases do occur. This has been emphasised by recent experiences in Australia and overseas. Each time we examine an animal and the clinical signs are not typical of what we expect to see in that species in our area we need to include exotic diseases in our list of differential diagnoses. You may be looking at the first case and you do not want to become famous as the vet who missed it!
Use the hotline number 1800 675 888 as hundreds of your colleagues do each year. You are not alone.