A recent survey of bulk tank milk samples in the United Kingdom has revealed a new strain of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA). Repeat sampling indicated microbial persistence in one herd. Although pasteurisation of milk should prevent human infection via the food chain, this finding does have public health implications for those exposed to the cattle.
A recent study in the Netherlands has confirmed that the transmissibility within humans of LA-MRSA is lower than that of MRSA’s not associated with livestock. (Emerging Infectious Diseases Vol. 19, No. 11, Nov 2013)
There have been recent reports of maedi (dyspnoea)-visna (wasting) disease in sheep in Japan (2012), Russia (March 2013), and in Scotland (Nov 2013), where up to 3% of flocks are positive. http://www.promedmail.org
Australia and New Zealand are free of this disease but these reports serve as a reminder to have this disease on our list of differential diagnoses.
Maedi-visna is a progressive, chronic disease caused by a lentivirus, which persists in monocytes and macrophages in the presence of antibodies. Clinical signs are the result of progressive interstitial pneumonitis or meningoencephalitis.
Infection is thought to occur most frequently by consumption of contaminated colostrum. No vaccines or treatments are available and control relies on quarantine and test and slaughter measures.
New cattle virus
A new species of astrovirus, BoAstV-NeuroS1, from cattle has been identified in the USA. The virus causes neurological signs similar to BSE in cattle. Encephalomyelitis involving the cerebellum, brainstem and spinal cord was evident in affected cattle. Its importance is in allowing differential diagnosis of BSE.
Novel cycloviruses in Asia and Africa
The virus, CyCV-VN, has been isolated from the cerebrospinal fluid of 4% of human patients in Vietnam showing signs of neurological disorders. The virus has also been detected in 58% of samples of faeces of poultry and pigs. Whilst cause and effect is yet to be determined, work is proceeding on developing a serological assay. http://bit.ly/mbiotip0613d
Dutch researchers analysed cerebrospinal fluid from human patients suffering paraplegia in Malawi. A novel cyclovirus was found in 10% of cases. http://wwwnc.cdc.gov/eid/article/19/9/13-0404_article.htm
Cycloviruses are members of the Circovirus family. They are non-enveloped, single strand DNA viruses commonly found in avian species. Animals may serve as the reservoirs for these viruses.
Dog circoviruses - USA
Dogs were reported to die following a short illness in several parts of the USA in 2013: in California (during Spring), in Ohio (September) and Michigan (October). Clinical signs included vomiting, bloody diarrhoea, extreme lethargy, inappetance and occasionally neurological problems. The pathology was of acute necrotising vasculitis and granulomatous lymphadenitis, similar to that in pigs with porcine circovirus infections. Early results indicate a novel strain of dog circovirus is involved. http://wwwnc.cdc.gov/eid/article/19/4/12-1390_article.htm
Human cases of H7N9 continue to be reported from China. To date 139 cases have been reported resulting in 45 deaths. Cases are restricted to the eastern provinces. Virus has been sourced mainly from poultry, the environment and human cases. The H7N9 viruses are of diverse types with reassortment occurring in wild birds and then in domestic birds. http://www.fao.org/h7n9
The first known human case of influenza caused by H6N1 has been reported in Taiwan. The isolate is a close match to viruses found in poultry in Taiwan. http://www.promedmail.org
Middle East Respiratory Syndrome (MERS)
Cases of the novel coronavirus MERS-CoV continue to be reported in the Middle East. Work has focussed on trying to determine the source of this virus. Bats are suspected to be the reservoir host.
A recent paper has reported that a fragment of a nucleotide from the faeces of Traphozous perforatus (Egyptian tomb bat) was 100% consistent with the MERS-CoV sequence. http://dx.doi.org/10.3201/eid1911.131172
Virus or antibodies to the virus are yet to be recovered from bats.
Further serosurveys of domestic animals has revealed high antibody titres to MERS-CoV in 98% of tested dromedary camels in Egypt. http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=20574
Egypt imports camels from Sudan, Djibouti and Ethiopia for slaughter but no clinical cases of MERS-CoV have been reported in these countries. In some countries including Saudi Arabia, human consumption of camel milk is gaining in popularity. The pattern of transmission in Saudi Arabia is consistent with movement of an animal reservoir, animal products or movement of infected people.
In November 2013 it was reported for the first time that the MERS-CoV had been recovered by PCR from samples of a camel belonging to a Saudi man infected with MERS-CoV. The camels had fever and rhinorrhea. It should be noted, that although MERS – CoV has been detected in camels, it seems clear that camels are not the source of virus for all human cases. http://www.promedmail.org
While dogs and cats are the usual hosts and mosquitoes the vectors, the increased geographical range of Dirofilaria immitis and D. repens infections in humans in Europe is believed to be the result of increased movements of pets, changes in vector populations, emergence of new vectors and climate change. http://cmr.asm.org/content/25/3/507.abstract
Recent reports of rabies cases in France and the Netherlands in imported pet animals not only serve to remind us of the importance of our quarantine border, but also that quarantine borders can be breached. It is important to promptly investigate and report any cases of potential rabies. http://www.promedmail.org
A recent survey of perceptions of Australian veterinarians to the risk of zoonotic disease and the infection control practices implemented provides food for thought for all those exposed to animals in their professional careers. The report found that 44.9% of those surveyed reported contracting a zoonosis during their career. http://www.sciencedirect.com/science/article/pii/S0167587713001268
The Australian Bureau of Agriculture and Resources Economics and Sciences recently released a report on the economic and social impacts of a hypothetical outbreak of foot and mouth disease. They estimate that a large multistate outbreak would cost between $49.3 billion and $51.8 billion over 10 years. This report emphasises the need for early detection to minimise eventual costs.
Points of interest
Lymphoproliferative disease virus was first detected in the USA in 2009. It has recently been reported to be affecting wild turkeys in New Hampshire with lesions which can resemble avian pox, except lesions can also appear on the feet. http://www.promedmail.org
Duck viral enteritis (DVE) was reported in Devon, UK in May 2013 as affecting Muscovy ducks. DVE is caused by a herpesvirus which affects ducks, geese and swans, causing vascular damage resulting in haemorrhage and necrosis of parenchymatous organs. http://www.promedmail.org
New pestiviruses, HoBi-like or BVDV-3, have been identified in Europe in foetal bovine serum imported from Brazil. These viruses cause clinical signs in cattle of growth retardation, reduced milk production, respiratory disease, poor fertility and mortality in young, similar to those seen with BVDV. Current tests do not differentiate between these viruses and BVDV. Reports of natural infection in Southeast Asia and Europe indicate infection may be widespread. http://vdi.sagepub.com/content/25/1/6
New diseases do occur. 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.