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A control program using 0.5 percent gammexane powder 0D.034) was undertaken in houses in humid Kenya hills (Teasdale 1952). Reapplications had to be made every month or two to control nymphs that had hatched from eggs, the latter being resistant to the chemical. Killing effects diminished in treated huts fifty days after application. The low cost of gammexane was said to allow its puchase and use by Africans.
Although most recent workers favor BH3 dusts over spray so. lutions, Anderson (1947) reported good control in Somaliland coffee houses with a three percent solution of gammexane in diesoline. "666 spray" (crude benzene hexachloride, 12% gamma isomer) at a dosage of 1,250 mgm. per square foot of soil was recommended by Hocking (1946), who found DDT at the same dosage less effective.
On the basis of experiments in two localities in Kenya, Heisch and Furlong (1954) recommend a spray of gamexane wettable powder P.52O rather than gammexane insect powder for tampan control.
Investigators have reported that DDT is of less effective. ness than gammexane in controlling tampans. Among these, Jepson (1947) found that five percent DDT dust is slower and less ef. fective than gammexane, although after about three weeks a mor. tality of fifty percent to eighty percent obtained. Holmes (1953) also indicated that gammexane provides a more complete and rapid kill than DDT. Annecke and Quin (1952) considered that various types of DDT applications lacked sufficient residual effect to be considered useful.
The inefficacy of many chemicals for killing 0. moubata and the usefulness of gamexane and of E605F (diethylQp.n1trophenyl. mono.thio.phosphate) for this purpose were reported by Enigk (1948). Belgian tests with three preparations of the gamma isomer have been reported by Pierquin (1950). Sprays of “Cyclotoxm contain. ing a large proportion of the gamma isomer killed about half the ticks in eight to ten days when applied in Belgian Congo huts.
In the laboratory, where the ticks could be kept in closer contact with the chemical, all died after varying lengths of time with different concentrations and preparations (Himpe and Pierquin 1951). The authors conclude that spraying a volatile substance on soil is of less value than mixing it with soil.
The possibility of controlling O. moubata by feeding hosts on certain chemicals was explored by-De Heillon (191.6). Fifty mgm. of pure gamma isomer of gammexane were mixed with agar a.nd water and fed to rabbits four or five times. The ticks fed onJ.y briefly and showed either incoordination or death afterwards. The domesticated tampan's predilection for human blood obviously limits the application of this interesting approach.
Q. moubata is also susceptible to arsenic compounds in the blood of_aE.'@s. Injections of neoarsphenandne have been used in rabbits for this purpose (De Meillon, Thorp, and Hardy 1948). The failure of 2:3 dimercaptopropanal (British anti...lewisite) to alter the toxicity of neoarsphenamine was described by Thorp, De Meillon, and Hardy (1948).
In testing insect and tick mrtality when exposed to dry insecticidal film, Busvine and Barnes (1948) found that Q. moubata nymphs are resistant to DDT but susceptible to gammexane and pyrethrins. Busvine and Nash (1953) also determined that films of oil solutions are better than dry films for testing insecticides because they give a sharper dose/kill relation.
The value of certain derivatives of phenol and naphthalene as s0i).1.-fumigants in hut floors has been suggested (Robinson 191.41: .
Derris powder failed to affect nymphal O. moubata in Russian laboratory tests (Mironov, Nabokov, and Kachalova I9T5). Pyrethrum sprays and dusts are highly toxic (Robinson 1942B.B,1943B,194./.B) but field tests have not been undertaken, probably due to high cost of pyrethrum and effectiveness of cheaper BID.
SuJ_fur dioxide or cyanide fumigation has little effect on 0. moubata, and sprays of kerosene and formalin are not success. 'ful_(F<§ns and Chorley 191.0). A spray consisting of 30 cc. turpentine, 50 cc. twenty.five percent alcohol, 5 cc. kerosene and a little white soap was suggested by these authors, though it is expensive and troublesome to prepare. Their best re. commendation was a coarse, roughly filtered spray consisting of 1% pounds of paradichlorobenzene in one gallon of kerosene applied under high pressure at the rate of twelve to fourteen gallons per two thousand square feet of surface (also reported by Hargreaves 1936).
The ovicidal value of concentrated vapors of chloroform, sul. furous acid, ammoniu sulfide, ethel dixanthogen, BH3 formalin, and phenol has been reported (Enigk and Grittner 1953).
A report of the resistance of Q. moubata to various sheep dips (Blacklock 1912) is of little contemporary Interest.
Disinfection of Personal Effects
Blankets, bedding, and clothing may be disinfected by ex. posure in a tight container to a temperatue of 82°C. for half an hou (Hopkins and Chorley 1940).
In a carefully conducted experiment, Garnham (1926) found, contrary to certain textbook statements, that burning of African huts infested with 0. moubata is an effective means of killing these ticks. He suggested pulling down the straw roofing ad piling it inside mud hut walls for burning. This may be the only means of control where the indigenous population does not work for pecuniary gain. Otherwise burning is uneconomdcal un. less the situation is serious. More permanent housing, in which infestation may be controlled or better still prevented, should be substituted whenever possible. Burning infested buildings has long been the indicated control method in many parts of Africa. Flame throwers are sometimes used to good effect where ticks are lodged in shallow cracks in buildings that withstand fire. Jack (1931) obtained control against tampans in nine.inch walls of pigsties by burning brushwood on both sides of them. Burning against only one side ad spraying with a ten percent emulsion of paraffin (i.e. kerosene) had failed.
A reward of sixpence for every twenty ticks collected on a South African farm yielded 73,000 ticks oreyear and over half a million in several years. Laborers placed a thin layer of drift manue along the inside walls of their huts and there collected the ticks as they came to hide. Small holes dug inside and out. side the doors and filled with drift manure were also found to be favorite hiding places (Annecke and Quin 1952).
_Q. moubata is the only known tick vector of African tick-borne relapsing fever (Borrelia duttonii) of East, Central, and South Africa. A few cases of t~se have been reported from Equatoria Province in the Sudan. No evidence supports certain published maps showing known extensive distribution of tick.-borne relapsing fever in many areas of the Sudan. It should be noted that populations of this tick from burrows of wild animals have not been found infested with spirochetes.
It is claimed that some specimens naturally infected with rickettsia, Coxiella burnetii, the causative organism of Q fever, have been foT'H in Ru a. rundi, and that in Kivu others have been taken infected with an organism referred to as “Bashi virusrickettsia“.
The etiologic agent of food poisoning, Salmonella enteritidis, has been recovered from this tick in Africa.
2. moubata has not actually been found infected in nature with the pathogenic organisms of any other human disease, but experimental data strongly indicate further research in this respect.
Tampan bites may cause considerable irritation. Circumstantial evidence suggests that persons long victimized by bites of this tick may develop an immunity to them.
Q. moubata is an experimental vector of fowl spirochetosis (Borrelia anserina). It is of negligible importance in transmission Sa
o mone a cteria and of Ae tianella $lorum (a protozoan). The Bacterium that causes avian c%oIera (Pas eure a avicida) sur_
vives only a few days in Q. moubata.
The use of Q. moubata and other Ornithodoros species for trans. porting a nuber of pathzgenic organisms for experimental puposes has been suggested.
This species is easily infected with Q fever (Coxiella burnetii) and is capable of transmitting the organism by its Bite. A diagnos. tic test for Q fever, using 2. moubata for feeding on a suspected host, has been developed.
Rickettsia owazekii, the causative organism of classical typhus, End R. t hi, that of muine typhus, develop in O. moubata. The former ricke sia can be transmitted transovarially'§nd-thE-latter can be found in eggs and coxal fluid of infected ticks.
No multiplication of R. tsuts amushi, the causative organism of scrub typhus, occurs in O. mouéata; the tick is therefore not a likely vector of this unusu§IIy_h3st.specific rickettsia.
O. moubata maintains infection with the virus of Russian spring.sumer (Far Eastern) encephalitis. It has also been shown that these ticks can be infected with western e uine encephalitis virus. The virus causing murine poliomyelitis (strain Columbia SK) is destroyed or inactivated in blood ingested by the tampan. Yellow fever is not transmissible by this tick. A Congo rickett. sia of the boutonneuse fever type (boutonneux.pourpre) remains virulent in ticks fed on infected guinea pigs for two months but not for six months.
Tularemia (Bacterium tularense) is transmitted by the bite of O. moubata and is §Iso transovarially transmitted to progeny. Bacillus anthracis, the causative organism of anthrax, is not
transmissible End apparently kills the ticks, although it does
remain virulent in the tick's body long after death. The etiologic agent of food poisoning, Salmonella enteritidis, has been recovered from this tick in Africa.