Posted on July 15, 2010 - by Russell

Warts and Ringworm

by Dr. Carla Chenette, Beef Cattle Breeding Extension Specialist
Dr. Duane Miksch, Extension Veterinarian, University of Kentucky, Princeton, KY

            While the economic impact of warts and ringworm in your herd may not be great compared to a disease like brucellosis, these two skin problems are prevalent and persistent in many herds of cattle.  Both certainly detract from the appearance of cattle and both are difficult to eliminate once established in a herd.
            Cattle with warts or ringworm are often not eligible for entry in shows, fairs or other places cattle are brought together, such as central bull test stations, because of their contagious nature.  Both spread rapidly through direct and indirect contact.  Both have fairly long incubation periods, prolonging the problems.  These diseases are easily transferred from one animal to another by simple management practices such as ear tagging and tattooing.  For example, if a calf with ringworm is clipped and the clipper blades are not disinfected prior to use on the next calf, the disease may be transmitted.  We will take a closer look at these two persistent cattle problems, explaining mode of action, some possible treatments and preventive procedures.
           
WARTS SPREAD QUICKLY 
            First, let’s consider warts.  Warts are caused by an infectious virus that is host specific, or in other words, is not passed from cows to pigs to humans under natural conditions.  On cattle, warts appear as large cauliflower-like lesions or small, horny bumps.  Most of the infective virus lives at the surface of the warts, explaining why they spread so quickly on an animal or through a herd of cattle.  The virus is spread through direct animal-to-animal contact or through indirect sources such as animal to feed bunk to next animal.  Skin wounds frequently lead to infections in “clean” animals if the wart virus is present.  Susceptible skin “wounds” are produced by routine management practices such as tattoos, ear tags or injections.  If an infected animal is tattooed, for example, the next animals that are tattooed with the same instrument are exposed to the virus and have a good chance of developing warts.
            Once warts are established, they can last on an individual animal for over a year and may become a total herd problem.  Usually it takes about two months for cattle that are infected to show warts after initial exposure to the virus.  So, although isolation of cattle with warts is recommended, they have probably already infected other animals before their disease was diagnosed.  Warts are a self-limiting disease as infected cattle build up natural immunity to re-exposure, but this immunity may be lost in time.
            Unfortunately, there is no simple treatment for warts that is always effective.  Surgical removal is one option, but be careful in the early growing stages, additional wart growth may be stimulated.  Conversely, when a few warts are surgically removed from an animal with extensive lesions, sometimes recovery seems to be hastened.  Therefore, remove warts only in totally developed or regressing stages.  Commercial vaccines are sometimes used, but they have had limited success.  A herd vaccine (autogenous vaccine) made from material collected from your cattle can be obtained through your veterinarian.  The vaccine is made from a suspension of ground wart tissue in which the virus has been killed with formalin.  Regular use of the vaccine as prescribed should continue for at least one year after the last wart has disappeared.  In addition to directly treating and vaccinating the cattle, the problem of contaminated fences, feeders, etc. should be addressed.  Formaldehyde fumigation at high humidity and high temperature will help to disinfect these indirect sources of wart infection.  Brushes, combs, clippers, tattoo instruments, etc. must be adequately cleaned and disinfected before reusing.

RINGWORM USUALLY WORSE
            If warts are a problem, it seems ringworm is usually worse.  Anyone who has treated ringworm on cattle knows it can be a never-ending chore, plus you may end up treating yourself as well since people can get this disease from cattle.  Ringworm is not host specific.  
            Ringworm is not associated with any kind of worm at all, but is a skin infection due to a fungus (aerobic actinomycete is the fancy name).  It is a worldwide problem affecting not only domestic animals, but wild animals as well.  In cattle, younger calves seem to be more susceptible, but all ages may be affected.  Ringworm takes two to four weeks to appear after exposure.  Then the hair falls out or breaks off in the affected area.  By two or three months, scaly, round asbestos-like plaques form.  The head and neck areas are most often affected on cattle, but if left untreated no area on the body is immune.  Ringworm seems to be at its worst during the winter, especially for cattle in confinement.  The summer sun appears to help clear up infections.
            Ringworm is tough as it can survive up to four years in the dry scabs and scales shed by cattle, plus it is easily transmitted by direct and indirect contact.  It is contagious from cattle to most other animals, including people.
            Several different treatments are recommended, but from experience, none is 100 percent effective.  Any treatments must be persistently applied to control ringworm and all are time consuming.
            For local treatment of ringworm, first remove the thick scabs with a brush and mild soap.  The infected areas should bleed slightly when the scales are removed.
            A few of the several recommended treatments for ringworm are:
            (1)  daily application of equal parts of tincture of iodine and glycerin,
            (2)  daily application of a 20 percent solution of sodium caprylate (for these remedies to be effective, all lesions must be soaked thoroughly each treatment),
            (3)  tincture of iodine or Lugol’s Solution applied every other day and
            (4)  thiabendazole (TBZ) applied directly to the infected area at least three times over a period of seven to nine days.
            Disinfection of equipment to prevent spread of ringworm is equally as important as it is in control of warts.  At times ringworm infections become widespread and seem to get out of hand.  Your veterinarian may prescribe systemic treatment, such as an intravenous solution of sodium iodine in water or oral griserofulvin.  Griserofulvin, by the way, is an expensive treatment to use in cattle.
            Ringworm is most severe and persistent in cattle under nutritional stress.  While poor nutrition is a contributing factor in this disease, sunlight seems to be nature’s treatment.
            Ringworm and warts are both common, irritating cattle problems that constantly try the patience of many a producer.  It takes determination, patience and persistence to control either.  Just be thankful they are seldom severe or fatal.

Source: 1997 TLBAA Breeders Handbook, article first printed in 1995.