Exotic Animal Disease Alerts Volume 6 Issue 2 - November 2012

Welcome

The EAD Newsletter has been rebadged in the format of a technical bulletin. We hope to be able to publish 4 issues each year and to include topics of interest to all Australian veterinarians on developments in emergency animal diseases. Our aim is to give a brief overview on a topic and then, if possible, to provide a source where you can find further information on that topic if it is of interest to you. We welcome your inputs and comments (see foot of page 2).

Schmallenberg virus (SBV) – Europe

In the last newsletter we highlighted a new arbovirus which was first reported in 2011 to be affecting sheep and cattle in Europe. The virus is a member of the Simbu serogroup of the genus Orthobunyavirus and is very similar to Akabane virus. It has also been found in wild cervids.

In 2011 cases were reported in Netherlands, Germany, Belgium and UK. It emerged in the same region of Europe as did BTV-8 virus. During 2012 evidence of SBV infection was reported in Belgium, Netherlands, Germany, France, Luxembourg, UK (including Scotland), Denmark, Spain, Italy, Switzerland, Sweden, Austria, Poland, Finland, Norway and Ireland.

SBV has been shown to cause disease in cattle (diarrhoea, fever and decreased milk production) and arthrogryposis-hydranencephaly in foetuses of cattle and sheep. It is not known to be zoonotic.

During 2012 much work has been undertaken. The vectors have been demonstrated to be Culicoides spp. The virus has been found in C. obsoletus complex, C. dewulfi and C. chiopterus.
(Schmallenberg virus information on the European Commission website or OIE scientists review knowledge on Schmallenberg virus)

Some countries are now imposing restrictive requirements for the importation of live animals and genetic materials from both affected and unaffected countries.

Epizootic haemorrhagic disease (EHD)

During summer and autumn in the USA there have been many reports of arboviral diseases, including EHD, eastern equine encephalitis and West Nile virus.

This season has resulted in major losses of wild cervids (mainly white-tailed deer, although mule deer, bighorn sheep, elk and pronghorn deer have also been affected) across many states in the eastern and central USA due to EHD. Serotypes EHDV-1 and EHDV-6 have been isolated. The vectors were Culicoides spp. EHD is an Orbivirus similar to bluetongue.

Clinical signs include swelling of face or neck, respiratory distress, fever, ulcers in the mouth, swollen blue tongue, or hoof overgrowth. Many carcasses are found close to water.
Hemorrhagic Disease n Wild Ruminants - Wildlife Health Bulletin (only available in PDF) [101 KB] from the National Wildlife Health Center website.

Lumpy skin disease

In Vol 4, Issue 2 we reviewed the distribution of this vector borne capripox disease of cattle. It is characterised by skin nodules, lymphadenitis and persistent fever. Production losses can be significant. Vectors include Culex and Aedes mosquitos and Stomoxys calcitrans.

In November 2011 Guinea reported an outbreak to the OIE. Affected animals were treated with ivermectin and oxytetracycline.

In July 2012, Israel reported two outbreaks in the north, near the borders with Syria and Lebanon. Prior to these reports outbreaks had been reported in southern Israel in 1989, 2006 and 2007.

Clinically affected animals were destroyed and all cattle in the infected zone (about 26,500 head) were vaccinated with a live-attenuated sheep-pox vaccine. Control of arthropods and quarantine measures were implemented. Outbreaks (29) continued until October 2012.

New publications

The World Livestock Disease Atlas is a quantitative analysis of global animal health data for the period 2006 – 2009.

EMPRES-i is a web-based application of FAO’s Emergency Prevention System (EMPRES) for transboundary animal and plant pests and diseases. The upgraded mapping section allows animal health maps to be overlaid by options such as livestock populations or terrain. Maps, graphs and data can be exported in various formats.

A recent issue of NZ MAFF Surveillance contained papers on Clinical and Epidemiological Investigation to Exclude Foot and mouth Disease in Cattle. It contains useful photographs of field cases of FMD.

Canine distemper

The disease is seen in Canidae (dogs, foxes, wolves), Mustelidae (ferret, mink, skunk), most Procyonidae (raccoon, coatimundi), and some Viveridae (binturong). Canine distemper is being reported in an increasing number of terrestrial species (gray fox, crab eating fox, African wild dog, African lion, black-footed ferret, Amur tiger, spotted hyena). Why? Is this a result of more widespread investigations?

Recently canine distemper has been reported as a cause of mortality in wild desert kit foxes in California. One possible source of the virus was coyote urine placed near the den to haze the foxes away from a development area. The coyote urine was used as a natural animal repellent but in this case it did not work.

Canine distemper has also been reported in Rhesus monkeys in a breeding facility in China. Incidence rate was reported as 25-60% and mortality rate as 5-30%. Authors noted a high rate of mutations in the virus and that surveillance for distemper in monkey populations and their carers should be considered.

Influenza A

There have been many reports of unusual cases of influenza in animals recently, probably a result of heightened surveillance. They demonstrate that flu viruses are not species specific.

Recent work has demonstrated that human susceptibility to pandemic influenza H1N1 is linked to mutation of the human interferon inducible transmembrane protein. Those with a shorter protein were more likely to be hospitalised.

In the USA, agricultural fairs are the point of greatest public exposure to pigs. A survey of 53 agricultural fairs in Ohio has found that 19% of all fairs had influenza A positive pigs with no clinical signs of disease. More than 300 human cases of influenza (H3N2 and H1N2) associated with pig exposure at fairs were reported during the summer of 2012. This research highlights the difficulty in preventing exposure to infected pigs in an agricultural fair setting.

In 2010 cats at an animal shelter in Seoul, South Korea showed signs of influenza (morbidity rate 100%, mortality rate 40%). Canine H3N2 was isolated. Are cats a potential source of infection for humans?