AAEP Convention Topics Preview: Fighting Infection

The latest information on scores of topics is presented at the AAEP convention; we can't report on them all, but we do try to bring you a representative sampling. This year, many of the topics can be grouped into five categories: fighting infection, reproduction, lameness/ injury, medicine, and predicting performance. In-depth coverage following the convention will be in our AAEP Wrap-Up (mailing with the February 2002 issue) and online at www.thehorse.com/aaep2001 after Nov. 24.

In-Depth: Antimicrobials

Veterinarians will have an opportunity to brush up on their understanding of antimicrobials during an in-depth session on Nov. 26. Antimicrobials are agents that destroy or inhibit the growth of microorganisms and are an often-controversial topic. Three individuals will be presenting current concepts in the selection and use of these agents. Susan White, DVM, MS, Dipl. ACVIM, a professor at the University of Georgia, will be moderating the session.

W. David Wilson, MRCVS, of the University of California-Davis, will discuss selection of antimicrobials. "He will talk about types of infections that occur in adult horses," says White. He will also discuss the antibiotics that have been proven effective at UC Davis.

Mark Papich, DVM, MS, will discuss the pharmacology of antimicrobial agents. "He will discuss correct dosages, and distribution of common antimicrobials (e.g., if a drug will penetrate infectious exudates)," explains White. He will also address why one antimicrobial agent might be preferable over another. "The information will be practical, concerning clinical pharmacology important in managing cases using particular antibiotics," she explains.

Compounded drugs are a controversial topic, and Joseph Bertone, DVM, MS, Dipl. ACVIM, will discuss their use. A drug might not be available in an administrable form for a particular equine patient, and a laboratory can create a compounded product made from available raw material that will suit the patient's needs. For that reason, compounding has a valuable place in veterinary medicine. But there's a flip side to the benefit, as some compounded drugs do not contain the concentration of the drug that's listed on the label, or are made with constituents that might affect absorption in orally administered drugs.

Bertone will address such questions as: What are the governmental controls on compounding drugs? How confident can you be that what you're getting is what they say you're getting? How does this lack of assurance affect antimicrobial resistance?

White suggested this in-depth session to Jerry Black, DVM, AAEP president-elect, because some of the antimicrobials with which practitioners are familiar have been removed from the market, and many practitioners have had little experience with the newer drugs that are available. "You never know when you're going to lose what you have," she explains. "There are different resistance patterns in bacteria that we're isolating today, and some of the old antimicrobials are no longer effective." She says that the session will provide take-home messages about infections in adult horses, as opposed to pediatrics. "Although pediatric patient treatment has been well covered by the AAEP, there has not been a seminar recently on treating bacterial infections in adult horses."

The Battle with Infectious Diseases

Infectious diseases are a special concern of horse owners who must try to fight an enemy they can't see. It's important to ensure that a new horse entering your farm does not have an infectious disease, and to keep any horse which becomes sick from infecting the entire herd with a disease such as strangles or equine herpesvirus. Besides making sure every horse is up-to-date on vaccinations, exactly how do horse owners and veterinarians go one-on-one with an infectious agent? Josie Traub-Dargatz, DVM, Dipl. ACVIM, Professor of Equine Medicine at Colorado State University's Veterinary Teaching Hospital and Biomedical Sciences Department in Fort Collins, Colo., will present "Infectious Control Strategies for Horses in the New Millennium" during the Dolly Green Lecture Series on Nov. 25.

Her talk will emphasize ways to control infectious diseases that don't necessarily rely on vaccinations. "Vaccination is an important way to control disease, yet there are other ways that we need to look at to prevent the spread of disease," she says.

Attendees will learn how to identify animals at risk of getting or spreading an infectious disease, and animals which show symptoms. Traub-Dargatz suggests that horse owners should not just leave a horse in quarantine for 10-14 days and do nothing. Checking the temperature--in addition to being on the lookout for obvious signs of sickness such as diarrhea, nasal discharge, or leftover feed--can be very useful in identifying and preventing the spread of an infectious disease. For instance, detecting a fever can indicate that a horse is infected with Streptococcus equi several days before a nasal discharge would show up.

Traub-Dargatz will also discuss the potential for the use of screening tests for new animals entering the premises. The use of screening tests depends on the type of equine population on the farm, which tests are desired by the farm's veterinarian, and from where the new horse might be coming. For instance, an owner might request a nasal swab to be performed on a horse which originated at a farm that just experienced a strangles outbreak.

Finally, Traub-Dargatz will discuss how to manage sick animals to prevent the spread of disease, including a general discussion on preventive hygiene. "These are big concepts that we've known about for a long time. Even the minimum effort can help," she says.

Control and Prevention of Foal Diarrhea Outbreaks

Foal diarrhea can be a life-threatening problem, with dehydration possible less than eight hours after the onset of symptoms. Roberta Dwyer, DVM, MS, Dipl. ACVPM, says that when trying to treat the foal, it helps to know the etiology or cause of the diarrhea. She says that in intensive breeding areas, foal diarrhea can be very common. "Unfortunately, on some farms it can be a yearly occurrence, especially with overcrowding and poor hygiene involved."

At the AAEP convention, Dwyer will present "Control and Prevention of Foal Diarrhea Outbreaks" in the in-depth session on Current Concepts in Pediatrics on Nov. 28.

Dwyer will discuss the various causes of foal diarrhea, which range from bacterial and viral causes to less-common factors. She will briefly review the effects of rotavirus, a highly contagious and very hardy viral disease in foals and other species that can cause diarrhea within 12-24 hours of exposure. She advises vaccinating against rotavirus and other diseases to prevent outbreaks.

Dwyer also will emphasize that veterinarians should educate farm owners not to spread manure from sick animals onto pastures, since the manure might contain an organism that can survive Mother Nature and make other horses sick. She also points out the great importance of washing surfaces before disinfection. Other sanitary measures include having handlers use latex gloves and washing their hands between handling sick and healthy animals.

Dwyer says she considers every case of foal diarrhea, except foal heat diarrhea, contagious until proven otherwise. This helps implement steps to stop a potential outbreak at the very beginning rather than after 10-20 foals have become sick and the infection has established itself on the farm. In her presentation, she will discuss how to isolate sick animals, implement disinfection protocols, use traffic control to avoid spreading disease, and use other management and hygiene measures.

Another important aspect of raising healthy foals is making sure that the newborn foal receives enough colostrum to provide much-needed maternal antibodies. If a foal does not receive enough good-quality colostrum, illness can result. Dwyer will talk about the importance of colostrum, signs of sickness other than obvious diarrhea, and complications from foal diarrhea. She will also discuss the latest research from other animal industries with regard to biosecurity.

"The cost of prevention--as in vaccinations for rotavirus, isolating new animals, and minimizing traffic between at-risk foals and older animals--all those things take planning and time. But if you can avert an outbreak of foal diarrhea, it is worth it," she says.

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