Thorough cleaning and disinfection of premises, buildings, pens, enclosures, equipment, personal protective clothing and vehicles that have been contaminated with manure, urine, and other discharges from infected animals are accomplished in the following order: removal and decontamination of bulky material by composting, burning, burying or chemical treatment; washing with water and detergent and finally the application of a disinfectant. The above procedures in some cases may not be relied upon to destroy all of the disease- causing organism under all conditions. An appropriate interval may be necessary after disinfection to permit the natural destruction of any surviving organisms before susceptible animals can again safely come in contact with the premise or items in question.

Vector control and eradication is an integral part of the disease eradication process in those instances where vectors are the sole or contributing factors in disease transmission.

The effective virucidal concentration of many disinfectant formulations has been demonstrated previously in successful decontamination programs and in laboratory studies. One need not commit the names of these compounds to memory, for representatives of three core disinfectant formulations can be used with confidence in an emergency situation against those disease agents of concern.

Examples of these are sodium hypochlorite (Compound No. 1), sodium hydroxide (Compound No. 2), and substituted phenolic compounds (Compound No. 3). The field veterinarian must be prepared for emergencies by having a combination of either Compound No. 1 or 2 plus Compound No. 3.

There are citations in the literature regarding the corrosiveness of Compounds Nos. 1 and 2; however, the immediate goal of a cleaning and disinfection program is to stop the spread of disease.

Compound No. 1

Sodium hypochlorite (NaOCL) or household bleach (stock concentration 5.25 percent available chlorine). This compound is effective against microbial agents of diseases, including ASF, FMD, HC, SVD, and VND at a concentration of 0.1 percent. It can be prepared at the time of use by adding approximately 30 cc (ml) of household bleach 10 a gallon of water. OR 1 gallon of bleach plus 50 gallons of water.

In areas heavily contaminated with secretions, excretions, and soil, there is a considerable organic demand for available chlorine. Therefore, the procedure must be repeated at least once. In fact, under such conditions a 3 percent solution of NaOCL should probably be used. To prepare this concentration, add 3 gallons of bleach to 2 gallons of water. This concentration is effective against a variety of agents of viral diseases such as the following:

Compound No. 2

Sodium hydroxide (NaOH), or lye, is available as crystals and can be obtained from pharmacies, grocery stores, agricultural supply stores, and often from a residence on the premises. It can be prepared as a 2 percent solution by mixing 1/3 cup of NaOH pellets per gallon of water.

Lye has a wide viral spectrum when used at this concentration (see the above list). However, it has limited effect against the viruses of ASF and HC. A considerably higher concentration is required to be effective (1).

Compound No. 3

Substituted phenolic compound. These compounds, such as One-Stroke Environ,* have potent virucidal activity against the viruses of ASF and HC when prepared as a 1 percent solution of stock disinfectant. A 1 percent concentration of the disinfectant must provide the following minimum concentrations of active ingredients:

Active Ingredient Percentage

o-benzy-p-chlorophenol 0.085 percent

o-phenylphenol 0.1 percent

p-tertiary amphylphenol 0 .02 percent

It can be prepared as a 1 percent solution by adding 38 cc(ml) or about 1 1/2 oz. of stock disinfectant per each gallon of water.

These types of compounds are effective against the viruses of African swine fever, avian influenza, hog cholera, and Newcastle disease.

These types of compounds are not effective against the viruses of FMD and SVD.

Other Disinfectant Compounds of Importance

We should mention the extremely effective virucidal activity of certain acidified iodophor compounds containing a generic formulation of polyethoxy-substituted polypropoxy-ethane complex. The active ingredient must provide a minimum use concentration of 0.02 percent titratable iodine. Some of these products are sold under the brand names of Vanodine,* FAM 30,* and Biocid.* At this time, however, these compounds are not available in the United States.

Two newer disinfectants are Oxine,* a chlorine dioxide disinfectant, and VerKonS,* a strong oxidizing disinfectant. These disinfectants are effective against viruses, bacteria, fungi, and spores, are essentially nonirritating, and are biodegradable.

Regarding the decontamination of aircraft, USDA, Animal and Plant Health Inspection Service, on the basis of research done by the aircraft industry, has shown that a 4 percent solution of sodium carbonate containing 0.1 percent sodium silicate has significant virucidal activity. Such a solution can be prepared by adding crystals of the chemicals to water in the following ratios:

Sodium carbonate Sodium silicate Water

1 lb (453g) 1 tablespoon (4.0 g) 3 gallons

6 lb (2.5 kg) 1 cup (24g) 19 gallons

GUIDE TO THE LITERATURE

1. STONE, S.S., and HESS, W.R. 1972. Effects of some disinfectants on African swine fever virus. Appl. Microbiol., 24:115122.

* Oxine — Bio-Cide Int., Inc., Norman, OK; VirKon S, Antec Int., distributor — DURVET, Bluesprings, MO.

* Disclaimer: Trade names are used in this publication solely to provide specific information. Mention of a trade name does not constitute a guarantee or warranty of the product by the U.S. Animal Health Association or an endorsement by the Association over other products not mentioned.

J. H. Blackwell, Ph.D., USDA. APHIS, VS, retired

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