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Foals With Interstitial Pneumonia May Have New Parvovirus

Foals in California have occasionally become seriously ill due to a form of pneumonia with an unknown cause, often in the spring and summer. Research from Dr. Eda Altan and colleagues at the University of California has found that a new parvovirus may be to blame.

The scientists looked at six foals who had succumbed to interstitial pneumonia, which affects the tissue surrounding the air sacs in lungs. Also called foal acute respiratory distress syndrome or severe bronchointerstitial pneumonia of foals, the condition often affects just one foal at a location.

Though the disease can look like other respiratory viral infections, no association to any other virus has been found.

The research team sequenced spleen, lung, and colon content samples from each of the foals after their deaths. They found equine copiparvovirus (genus of viruses in subfamily Parvovirinae of the virus family Parvoviridae) as well three previously uncharacterized viruses in the samples.

The study team went on to classify the unknown viruses as members of new ungulate protoparvovirus and bocaparvovirus species in the Parvoviridae family.

These discoveries don't prove that these viruses play a role in interstitial pneumonia, the scientists said. Additional studies are required to prove a disease-causing link.

Read the study here.

Study: Horses And Chronic Hepatitis

The most common cause of acute viral hepatitis in horses is serum hepatitis, also called Theiler's disease, which causes liver atrophy and necrosis. Worldwide outbreaks have been reported in conjunction with the use of equine-derived blood products, including tetanus antitoxin, botulinum antitoxin, equine plasma, Streptococcus equi antiserum and pregnant mare's serum.

Between 1.4 and 18 percent of horses receiving an equine-derived product have reported a sudden or severe hepatitis infection. A novel parvovirus dubbed an equine parvovirus-hepatitis (EqPVH) has been identified as the cause of Thieler's disease in horse serum samples the United States, Canada, New Zealand, Italy, and Germany, indicating that the parvovirus occurs worldwide.

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Interestingly, EqPV-H has also been found in horses with Thieler's disease that did not receive biological equine serums.

Dr. Birthe Reinecke, postdoctoral fellow with the Institute of Experimental Virology, and a team of scientists created a study to determine if chronic EqPV-H infection is a possibility and if cross-species infection can occur. The team used 124 German horses for a five-year study as well as 318 human serum samples: 147 samples were from humans with no horse contact and 171 samples were from humans who had contact with horses for their work. They also used 494 donkey serum samples from Germany, Italy and Bulgaria, and archived samples from zebras.

Most horses used in the study were EqPV-H negative, but some has virus in their blood. The team determined that horses can be infected with the disease for up to five years, even if they show no clinical signs of the disease. About 1 percent of donkeys were positive for EqPV-H (5 of the 494 animals), meaning that the disease can also affect donkeys.

Read the full study here.

Novel Circovirus Identified In A Kentucky Horse

A novel circovirus has been found in a Kentucky horse with liver disease, though it remains unclear whether the virus was the cause of the horse's health problems.

Circoviruses can affect pigs, birds, elk, dogs, cows, pandas, bears, bobcats, pumas, foxes, mink, seals, bats, rodents, fish, and bobcats. They can have no effect on some animals and may be lethal to others.

Dr. Alvin Hui serum tested five horses in Kentucky: one ill and four healthy. The researchers discovered parvovirus-H, equus anellovirus and some distantly related mammalian circoviruses sequences. The circovirus was present in the ill horse, which was a pregnant mare with hepatitis and a fever. The mare was also positive for equine parvovirus-H, which could have been the cause of the liver disease.

The scientists were able to completely map the genome of the equine circovirus 1 strain Charaf (EqCV1-Charaf). The team determined that the equine circovirus genome is most closely related to pig circoviruses PCV1 and PCV2, which are distributed worldwide, and to a Canadian elk circovirus, which has been reported just once.

The team concluded that EqCV1 is a new species in the circovirus genus and the first reported in a horse. Whether the circovirus played a role in the mare's hepatitis is uncertain as the virus's disease-causing ability is unclear.

Read the full article from the journal Viruses.

AAEP Publishes Equine Parvovirus-Hepatitis Virus Guidelines

The American Association of Equine Practitioners (AAEP) has published on its website comprehensive guidelines to educate practitioners about transmission, risk factors, clinical signs and other considerations pertaining to equine parvovirus-hepatitis virus (EqPV-H), a recently discovered virus capable of causing hepatitis in infected horses.

Two distinct etiologies of EqPV-H infection are recognized: biologic transmission and non-biologic transmission. Asymptomatic infection is common; only a small percentage of infected horses will develop clinical signs of liver disease.

“Drs. Thomas Divers and Bud Tennant of Cornell University College of Veterinary Medicine discovered that this novel parvovirus was associated with the disease 'serum sickness' in horses who had recently been administered a parvovirus-infected biologic,” said guidelines co-author Dr. Piper Norton. “Because of their seminal research and active ongoing research, information will be learned about this virus that will assist in making biologics safer for use in horses and help with diagnosis and treatment of this disease.”

EqPV-H is a recently discovered virus and the focus of rapidly evolving research. These guidelines reflect knowledge at the time of writing. Practitioners are encouraged to seek further consultation for questions regarding clinical cases of EqPV-H.

The Equine Parvovirus-Hepatitis Virus Guidelines were authored by Linda Mittel, MSPH, DVM; Piper Norton, DVM, DACVIM; Joy Tomlinson, DVM, DACVIM; and Thomas Divers, DVM, DACVIM, DACVECC. The guidelines were reviewed and approved by the AAEP's Infectious Disease Committee and board of directors. View the guidelines or save them to your mobile device as a PDF file for future reference here.

In addition to EqPV-H, AAEP guidelines for 21 other equine infectious diseases are available here. In addition, two foreign animal disease guidelines — for African horse sickness and Glanders — are also available.