Survey and Determination of Resistance in Mosquitoes and Houseflies of Karachi Region

Abstract

Discoveries of new synthetic insecticides after World War 2 have sparked existing advancement and major breakthroughs in the control of insect enemies. Modern insecticides are effective, reliable and cheap but inept pesticides usages have encountered their effectiveness with resistance in different domestic and agricultural pests. Mosquitoes and houseflies have been known as man’s worst enemies, because of their role in the transmission of various fatal diseases. Such as malaria, yellow fever, Filariasis, diarrhoea etc. as mentioned in forgoing lines, likewise despite early successes in vector control by the use of insecticide chemicals there is an alarming proliferation of resistance problems in mosquitoes and house files in addition to their polluting effects. The first of successful synthetic insecticides and the first to which insect developed resistance was DDT (1, 1,1-tricholoro,2-2-bis-(p-Cholorophenyl)-ethane). Several factors may not be involved in DDT resistance and they may vary in importance from species to species and strain to strain .They include for instance alteration in the permeability of the cuticle to the insecticide and changes in the permeability of the cuticles to the insecticides and changes in the efficiency of storage of the toxicant in sites remote from its point of action. DDT(OC): It is effective against a great number of insect pest but development of resistance produced many problems. It was used extensively during Malaria Eradication Program during late 50’s and early 60’s in Pakistan. A large number of workers worked on this aspect e.g. Chattoraj and Brown (1960), Khan and Brown (1961), Pillai and Brown (1965) , Wood( 1967,1970) , Khan and Terrier (1968) , Gaaboub et al. (1975), Georghiou and Pasteur (1978) , Sawicki (1978), Lauric and Merrerll (1979) , Woodward and Stwernberg(1979), Malinowski (1980) , Rathore and Wood( 1985) , Sexena (1988) , Severin (1989) , Malcolm (1990), Suarez et al. (1990) , Lines and Nassor ( 1991) , Shams et al. (1991) Malathion (OP): Among them organ phosphorus insecticides e.g. Malathion owe their history to the inhibition of the acetylcholine ersterase which has a vital role in their maintained of the nerve activity. Malathion was rendered ineffective due to development of resistance in mosquitoes, houseflies, cockroaches and other household insect. The resistance against Malathion also developed due to continuous use of their pesticides during MEP in late 60’s and 70’. Numerous researches have done work on this aspect throughout the world (Van Asperen and Oppennoorth 1960, Matsummura and Hogendik 1964, Yasotomi 1970, Morgan el at. 1972, Roslavtseva el at.1975, Pinterove el at. 1977, Kano el at. 1978, Kuenast and Meisner 1979, Kudasmatsu el at. 1979, Georghiou and Pasteur 1980, Georghiou and Mellon 1983, Musjtaq and Richard (1984) , Case and Kauffman 1985 , kao el at.1985, Rathor and wood 1985, El-khatib and Georghiou 1985, Zouhair el at.1985, Hemingway el at.1986, Mouches el at. 1987, Naqvi 1987 , Bull and Pryor 1990) in areas where insecticides were used extensively tow types of resistance occurred . i.e. cross resistance and multiple resistance . Cross residence is the phenomenon whereby an insect population becomes resistance to two or more chemically distinct insecticides as a result of selection by one insecticide only. DDT and Malathion also produced cross resistance and many workers reported their work on cross resisatncve anmd soe aere reported here. Kudamalsu el at. 1979), Hemingway and Davidson (1984) , Respicio and Heitz (1986), Roush and Wright (1986) , Sand el at. (1986), Scott el at. (1986) Ahuja (1988) , Amin and Hemingway (1989) , Mueller (1989), Saleem and Shakoori (1989) , Huang and Pin-Jian (1989) , Ishaq and Gillani (1990), Raghavendra el at. 1991, Shakoori and Salweem (1991).

Cyfluthrin (Pyrethroids): Nowadays pyrethroids are most widely used in different fields (agriculture, household, commercial, health sector etc.) and control the pests successfully. They act at the same or similar sites as OC compound. The most compelling evidence for similar actions comes from genetics. Busvine (1951) demonstrated cross-resistance to pyrethrum in an Italian strain of housefly that was resistant to knockdown by DDT later termed knockdown resistive (Kdr) this factor was shown to be recessive, and to be expressed through sites or nerve insensitivity (Farnham 1977) with some important exception (Sawick 1978.This gene selectively confers resistance to their entire category of both DDT and pyrethroid compounds.

Different pyrethroids (permithrin , cypermethroium , cyfluthrin , deltamethrin, decamethrin etc.) were used and they turned out to be active on a wide variety of different insects a large number of scientist worked on pyrethoids mode of actions. Like Malcolm (1983) ,Walker (1983) , Bitran el at. 1984, Behrenz and Elbert (1985), Poyne el at. 1985. Makundi and Rhode 1986, Rajavel el at. 1987 ,Forter and Woodward 1987, Leonard el at. 1989, Cochran (1990, Fikro and hayes (1990) , harwood el at. 1991 , Karnatak el at. 1991, kumar el at. 1991 , Osman el at. 1991, Thomas el at. 1991, Geden el at. 1992. Neem (Allelochemicals) Neem tree which grows in the semiarid region in the world, is the most useful plant. Pesticides prepared from it are effective against different kinds of insect species. Use of neem leaves for protection of stored grains , household pets , hygiene pest and other commodities has been known since ancient times and different parts of neem tree and their isolated fraction and extracts have been tested against a large number of insects throughout the world. Pruthi 1937 first time tested their efficacy as a repellent against storage pest. Afterward Siddiqui (1942) isolated different neem fraction. The most active neem consistent, azadirachtin was isolated by Butterworth and Morgan (1971). Warthen 1979, Meisner el at. 1981 reported IGR antifeedant feeding deterrent and inhibiting effect of a wide variety of insects it is also disrupted growth cycle (metamorphosis) and produce abnormal adult , adult or papal intermediate ( Rembold and Seiber 1981, rembold el at. 1984 . azadirachitin has a string influence on fecundity and egg fertility Steets and Schmutter 1975, Ascher 1981. Reasechers on dififernt aspects of neem have been done by various workers (Ruscoe 1972, Qadri and Mushtaq 1979, sexdena el at. 1980, Jacobson el at. 1984, chavan 1984 , mwangi and rembold 1988, ludlm and peter 1988, miller and chamberlain 1989, Blaney el at. , 1990, Parkman and peinkowski 1990, Thomas el at.1992 ) No reference on the development resistance against neem products has been found except Vollinger 1987 who reported the development of resistance aagainst neem extracts in comparison with deltamethrin in case of Pluella xylostella,. He reported that NSKE (nee m extract) treated line showed no sign of resistance up to 42 generation whereas deltamethrin treated lines developed 20 and 35 times resistance. In the view of the above facts that the resistance possibly do not develop quickly against neem products it was decided that such studies be undertaken on the local neem fraction which proved effective. Naqvi and Tabassum 1992 , undertook this research under PSF project no. S-KU/bio-161 and have been reported these result here. Justification; Karachi is cosmopolitan city, the population of this city is around ten million .large number of people excessively use insecticides for noxious domestic insect pets. Due to misuse, overuse or unnessccacry use of pesticides resistance has developed in the domestic pest of Karachi and other parts of Pakistan. However, despite all the harmful effects, no systematic work for determination of resistance has been done in this region. However, Rather 1986, naqvi 1987, naqvi and akhtar 1987, naqvi el at.1988, azmi el at.1988 , akhtar 1989, azmi el at. 1990 a&b, azmi and naqvi 1991, shams el at.1991 and azmi 1992, have been reported resistance in insect in a Pakistan. As regard of the work other aspect such as biochemical estimation and histochemicial localization in the resistant , treated and non-treated insects, some work has been reported (van-asperen and oppenoorth 1990, naqvi el at.1968 a&b, naqvi el at. 1969a&b, yasotomi 1970- , yaseen el at. 1971, sudderuddin and lim 1978, charlisle and Loughton 1979, naqvi el at. 1987, azmi 1987 , azmi el at. 1988, moores el at. 1988 , akhtar 2990 azmi 1990 , bull and peryor , hua tang el at. 1990, and azmi 1992. In view of above facts work on the survey and determination of resistance in houseflies and mosquitoes of Karachi region was undertaken. Identification of the species of mosquitoes and population density of houseflies and mosquitoes at various spots were carried out. Moreover, resistance level was obtained by WHO method. For further confirmation enzyme activity (cholinesterase, DDT- dehydrochlorinase, GOT, GPT) was also determined spectrophotometric ally and by sunung HPLC/GC . In addition to new plants products (rb- a, neem products) were compared with cyfluthrin FOR OVERCOMING THE Resistance problem which generally develop against convectional pesticides. it is hoped that these findings will save foreign exchange by using safe and indigenous products.