Operation Big Itch was a U.S. entomological warfare

Entomological warfare

Entomological warfare is a type of biological warfare that uses insects to attack the enemy. The concept has existed for centuries and research and development have continued into the modern era...

 field test using uninfected flea

Flea

Flea is the common name for insects of the order Siphonaptera which are wingless insects with mouthparts adapted for piercing skin and sucking blood...

s to determine their coverage and survivability as a vector for biological agent

Biological agent

A biological agent — also called bio-agent or biological threat agent — is a bacterium, virus, prion, or fungus which may cause infection, allergy, toxicity or otherwise create a hazard to human health. They can be used as a biological weapon in bioterrorism or biological warfare...

s. The tests were conducted at Dugway Proving Ground

Dugway Proving Ground

Dugway Proving Ground is a US Army facility located approximately 85 miles southwest of Salt Lake City, Utah in southern Tooele County and just north of Juab County...

 in 1954.

Operation

Operation Big Itch was a September 1954 series of tests at Dugway Proving Ground in Utah. The tests were designed to determine coverage patterns and survivability of the tropical rat flea (Xenopsylla cheopis) for use in biological warfare

Biological warfare

Biological warfare is the use of biological toxins or infectious agents such as bacteria, viruses, and fungi with intent to kill or incapacitate humans, animals or plants as an act of war...

 as disease vector. The fleas used in these trials were not infected by any biological agent. The fleas were loaded into two types of munitions and dropped from the air. The E14 bomb and E23 bomb, which could be clustered into the E86 cluster bomb

E86 cluster bomb

The E86 cluster bomb was an American biological cluster bomb first developed in 1951. Though the U.S. military intended to procure 6,000 E86s, the program was halted in the first half of the 1950s.-History:...

 and E77 bomb, respectively. When the cluster bomb

Cluster bomb

A cluster munition is a form of air-dropped or ground-launched explosive weapon that releases or ejects smaller sub-munitions. Commonly, this is a cluster bomb that ejects explosive bomblets that are designed to kill enemy personnel and destroy vehicles...

s reached 2,000 or 1,000 feet (600 or 300 m) the bomblets would drop via parachute, disseminating their vector.

The E14 was designed to hold 100,000 fleas and the E23 was designed to hold 200,000 fleas but the E23 failed in over half of the preliminary Big Itch tests. E23s malfunctioned during testing and the fleas were released into the aircraft where they bit the pilot, bombadier and an observer. As a result, the remaining Big Itch tests were conducted using only the smaller capacity E14. Guinea pig

Guinea pig

The guinea pig , also called the cavy, is a species of rodent belonging to the family Caviidae and the genus Cavia. Despite their common name, these animals are not in the pig family, nor are they from Guinea...

s were used as test subjects and placed around a 660 yard circular grid.

Results

Big Itch proved successful, the tests showed that not only could the fleas survive the drop from an airplane but they also soon attached themselves to hosts. The weapon proved able to cover a battalion-sized target area and disrupt operations for up to one day. The one-day limit was due to the activity of the fleas; the air dropped fleas were only active for about 24 hours.