Entomological warfare (EW) is a specific type of biological warfare (BW) that uses insects in a direct attack or as vectors to deliver a biological agent, such as plague or cholera. Essentially, EW exists in three varieties. One type of EW involves infecting insects with a pathogen and then dispersing the insects over target areas. The insects then act as a vector, infecting any person or animal they might bite. Another type of EW is a direct insect attack against crops; the insect may not be infected with any pathogen but instead represents a threat to agriculture. The final method of entomological warfare is to use uninfected insects, such as bees, to directly attack the enemy.
The US government has conducted multiple operations, testing insects for entomological warfare. Including releasing the insects on American citizens inside US boarders. The majority of the operations conducted are classified. However, there are a few operations that are known.
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 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 and E77 bomb, respectively. When the cluster bombs 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, bombardier and an observer. As a result, the remaining Big Itch tests were conducted using only the smaller capacity E14. Guinea pigs were used as test subjects and placed around a 660-yard (600 m) circular grid.
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.
Operation Big Buzz occurred in May 1955 in the U.S. State of Georgia. The operation was a field test designed to determine the feasibility of producing, storing, loading into munitions, and dispersing from aircraft the yellow fever mosquito (though these were not infected for the test) (Aedes aegypti). The second goal of the operation was to determine whether the mosquitoes would survive their dispersion and seek meals on the ground. Around 330,000 uninfected mosquitoes were dropped from aircraft in E14 bombs and dispersed from the ground. In total about one million female mosquitoes were bred for the testing; remaining mosquitoes were used in munitions loading and storage tests. Those mosquitoes that were air-dispersed were dropped from airplanes 300 feet (91 m) above the ground, spreading out on their own and due to the wind.
Mosquitoes were collected as far away as 2,000 feet (610 m) from the release site. They were also active in seeking blood meals from humans and guinea pigs.
In 1961, the U.S Army Chemical Corps conducted Operation Bellwether II, which essentially involved the field testing of certain entomological vector-agent systems on personnel.
The unclassified Bellwether II document states that a “releases of uninfected, starved, virgin female mosquitoes were used to evaluate the effects of varying the vector and host ratio,” and, “determining the effect of the presence or absence of overt movement of the human samplers upon the outdoor biting rate,” also, “investigate methods of placement of human samplers in open terrain and within built-up areas.”
The Bellwether II document concluding that, “no conclusive findings were generated as to the effect of host concentration,” and that, “when the number of vectors was increased by a factor of 10, approximately 10 times as many bites were received and the proportion of hosts bitten was increased by an average of 36 percent.”
Opsec News located a detailed PDF file for Operation Bellwether I, online. However, the document is listed as secret and does not appear to be declassified.
Other operations said to have taken place include:
Operation Drop Kick was a 1956 U.S. entomological warfare field testing program that deployed Aedes aegypti mosquitoes to carry a biological warfare agent. Operation Drop Kick apparently included a 1956 test in Savannah, Georgia, where uninfected mosquitoes were released in a residential neighborhood and another 1956 test in Avon Park Bombing Range, Florida, where 600,000 mosquitoes were released by plane. The 1964 movie Dr. Strangelove also refers to an Operation Drop Kick.
Operation Magic Sword was U.S. military operation undertaken in 1965. It was designed to ascertain the effectiveness of releasing mosquito vectors for biological agents at sea. It took place off the southeastern coast of the United States and employed yellow fever mosquitoes with the hope of assessing their biting habits following an ocean-borne release.
Magic Sword showed that when coupled with ocean winds that the mosquitoes could travel up to three and one-half miles to shore. The operation also showed that if needed the mosquitoes could be kept alive for cross-ocean journeys.