The mange mite is back. Just about stamped out in the early '90s, the most common external parasite problem of hogs worldwide, is mounting a serious comeback.

“Packing plant carcass surveys, along with reports from swine veterinarians and pork producers, point to increasing levels of sarcoptic mange mite infestations in swine herds,” explains Steve Parker, director of Merial's North American swine business unit.

To combat the increased severity, Merial is relaunching its IVOMEC (ivermectin) for swine Herd Mange/Lice Elimination (HM/LE) program that eliminates parasite problems from the herd. The program incorporates all three IVOMEC for Swine Brand formulations, IVOMEC 1% Injection for Swine, IVOMEC 0.27% Injection for Grower and Feeder Pigs or IVOMEC Premix for Swine.

The program is really geared to eradication of swine mange, says Parker, admitting the hog louse has virtually been eliminated.

Surveying the Damage

When mange strikes, it causes losses in productivity estimated by Merial officials at $84-$115/sow unit/year. Included in that figure is an average increase of 8.6 days to market, litters weighing 9.1 lb. less at weaning and 0.8 fewer pigs weaned/year.

There is intense discomfort in the ears and folds of skin in affected hogs where mange mites live and breed. This results in damage to equipment from rubbing. The infestation also decreases hog value at slaughter due to trim loss.

Reemerging Problem

A random survey of seven Midwest hog packing plants in 1996 found 43% of 1,442 operations showed signs of dermatitis and skin lesions due to mange, says Parker. The survey represented more than 27,000 hogs.

USDA's National Animal Health Monitoring System (NAHMS) Swine 2000 survey reports the percent of animals for which there was regular use of prevention practices for mange/lice. The NAHMS survey reported regular treatment in 12% of piglets, 15.5% of growing and finishing pigs, 36.9% of sows/gilts and 46.6% of boars.

There are several reasons for the upswing in the number of cases. “Swine mange is reemerging partly because low levels of mange mites are hard to detect in herds,” points out Parker. “Another reason is poor economic conditions in recent years led to lapses in control and opened the door to reinfestation.” Increased specialization in pork production means more animals move between operations, spreading mange, he notes.

Moreover, the mite Sarcoptes scabiei var. suis, the cause of sarcoptic mange, will remain widespread in swine herds unless eliminated by specific eradication measures, says Marty Mohr, DVM, Swine Vet Center, St. Peter, MN. Herd prevalence estimates of 50% or greater have been reported in many countries, including the United States.

Eradication Details

So the field-proven HM/LE program can be essential to eradicating mange, he says. The first option involves injection of all hogs in all phases of production. The second protocol combines use of injections and in-feed formulations of IVOMEC. The third plan involves in-feed administration for all pigs, except injection for pigs off feed or nursing.

The three options allow producers and veterinarians to tailor the HM/LE program to fit management and facility capabilities.

To prevent program failure, Mohr offers this four-point plan:

  1. HM/LE preparation

    Design the elimination program based on the needs of the production system. No matter which treatment option is selected, make sure a two-dose program is followed, adds Parker. The first dose is to kill the established mange mite population. The second dose is to clean up any residual infection. The treatments should be at least 18-21 days apart, because that is the life cycle of the mange mite, he says.

    Biosecurity is paramount, says Mohr. During elimination, stop new animal introductions. Thoroughly clean and disinfect all transport vehicles. Burn any bedding offsite. Use a mange spray to kill any residual mites that may be left in the environment.

    Limit staff movement between farm sites. Ban personnel movement from infected sites to mange-free sites. Separate clean-dirty equipment and supplies to prevent cross-contamination.

    Don't estimate weights. Weigh animals to determine proper dosing levels.

    Calibrate syringes carefully to ensure proper dosing for injecting small pigs and breeding stock alike.

    Destroy old boots and coveralls, preferably by burning. Clean and disinfect new boots.

    Sell off culls, non-productive females and market-ready animals before implementation.

  2. Financial implications

    Draft a budget to compare short-term vs. long-term cost benefits. Roger Riggs, Merial sales manager, reports the initial cost of the program is $18/20/inventoried female. That includes all pigs in all phases of production in a farrow-to-finish operation. Return on investment averages six months.

  3. IVOMEC Premix for mange elimination

    Completely clean out all old feed, ensure feeders aren't plugged and will deliver feed efficiently to the pigs. Verify product usage.

  4. HM/LE Implementation

    Ensure adequate trained staff is available to carry out the program. Mark injected pigs. Change needles every 20-25 injections. Confirm feed deliveries and feed disappearance if using the feed premix protocol.

Merial officials stress that program participation must involve a swine veterinarian.

After elimination, continue to isolate and treat all replacement stock, stresses Riggs, including those from the finishing area. Conduct slaughter checks or carcass evaluations to assure free status.

Declares Parker: “We have the tools to eradicate this disease. Let's use the tools.”

NSIF Holds Annual Conference

The National Swine Improvement Federation's 26th Annual Conference and Meeting is scheduled for Dec. 6-7 at the Embassy Suites Hotel in St. Louis, MO.

At this year's conference, a poster session will describe the latest research, technological and systems information for swine breeders.

Educational program will feature talks on gene discovery and functional genomics in the pig, use of genomics in a genetic selection program and genetic estimates for meat quality and production traits in pigs.

Other talks focus on the impact of foreign animal diseases on selection programs and competition and animal well being.

Registration after Nov. 1 is $150/person. For more information contact Ken Stalder at (731) 425-4705 or e-mail For reservations, call the hotel (314) 241-4200.