Colonization of the Oasis Malaria Vector, Anopheles Sergentii, in Egypt
Total Page:16
File Type:pdf, Size:1020Kb
104 J. Au. Mosq. CoNrnol Assoc. Vor. 2, No. I COLONIZATION OF THE OASIS techniques, the Siwa colony was maintained MALARIA VECTOR, nine months through the eighth generation. ANOPHELESSERGENTII, IN EGYPTI The Faiyum strains were maintained for l0 generations over one year. JOHN C. BEIER',MAGDA S. BEIER3, EPTESAM A, EL KORDYJ,SHERIF EL SAID3ano Field collected larvae were brought to the MOHAMED A. KENAWY3 insectary in Cairo for colonization. The insec- tary was maintained at 20-30'C, 40-80% RH, Anophelessergentii (Theobald) is the principal with illumination by fluorescent lighting for vector of oasis-desert malaria, and shows approximately 8 hours a day. unique physiological and behavioral adapt- The artificial mating technique was similar to ability in its extreme environment (Farid 1956). that employed at the National Institutes of Throughout the range of this species,including Health (R. Gwadz, personal communication) North Africa, the Middle East and Pakisran and described by Ow Yang et al. (1963). Fe- (Knight and Stone 1977), it is an efficient males, held either in a 30 cm3 cage, or in a 300 malaria vector (Farid 1956). In Egypt, An. ml screened cup, were offered a human blood sergentiitransmits malaria in the Western Desert meal immediately prior to mating. Males were Oases and in Faiyum Oasis (Halawani and lightly anesthetized by ether and pinned to an Shawarby 1957),and on two occasionshas been applicator stick with a minuten pin. This spe- found naturally infected with sporozoites (Farid cies, in comparison to other established 1940; J. C. Beier and M. A. Kenawy, unpub- AnopheLescolonies maintained by this technique lished data). was difficult to force-mate and all matings were Studies on An. sergentiiin the laboratory have made using a dissecting microscope at 100- been limited to observarions of field-collected 150X. Experienced individuals could mate up specimens (Saliternik 1955) due ro rhe lack of to 20 females per hour. Matings were most suc- laboratory colonies. Many unsuccessful efforts cessful using males 3-6 days of age. have been made to colonize this speciesin Egypt Mated females were held in 30 cm3 wooden (Farid 1956; M. A. Kenawy, personal com- framed cages and provided with l0% sucrose munication). Except for an unpublished report on cotton which was changed daily. A 12 cm to WHO on the colonization of this speciesfrom diam. bowl lined with filter paper and % filled Jordan by G. Davidson in 1967 (seeZahara), we with distilled water was used for oviposition. are unaware of other colonization attempts. Eggs were collected and usually allowed to The main obstacle to colonization is that this hatch in the oviposition bowls. Mated females species is eurygamous as it does not mate were refed in the cages on human blood and it readily under laboratory conditions. This re- was common to refeed the same females up to 6 port describes the establishment of three col- times over a l-month period, as most mated onies of An. sergentii. females survived I month. The initial An. sergentii colony originated First instar larvae were placed in 30 cm diam. from more than 500 larvae collected in Siwa round enameled pans half-filled with water. Oasis, Matrouh Governorate, Egypt, during Usually, larvae were reared in a mud slurrv (2 October 1982. The other rwo colonies origi- kg clay soil stirred in 50 liters tap water; water nated from collections of over 200 larvae from was used for larvae after 2 days). Preliminary Sinnuris District, Faiyum Governorate during experiments showed faster development and June and October, 1983. Using artificial mating better survival in this water when compared to distilled or tap water. Larvae were fed ground dog food pellets (fat-free), once a day. t This study was supported by research contract Observations were made using the Faiyum No. N0l AI 22667/NIH-NIAID, entitled "Epidemiology + and Control of Arthropod-Borne Dis- colonies in generations 2 to 6 held at 27 2"C. eases in Egypt" between Ain Shams University, Ab- With individual females held in 300 ml bassia,Cairo, Egypt and the National Institute of Al- screened paper cups, containing 50 ml of water; lergy and Infectious Diseases(NIAID), National In- the duration of the first and second gono- stitutesof Health (NIH), Bethesda,Maryland, U.S.A. trophic cycleswere 4.9 + 0.9 (n : 55) and 3.6 I ? National Institutes of Health (NIAID) resident 0.7 (n : I l), days, respectively.The number of consultant to the Ain Shams Center. Present address: eggs per female ranged from 2l to 148, with Department of Immunology, WRAIR, Walter Reed means of 66.4 + 26.8 and 74.1 'r 23.7 for the Army Medical Center, Washington, DC 20307-5100. first and second gonotrophic cycles, respec- r Ain Shams Research and Training Center on Vectors of Diseases,Ain Shams University, Abbassia, tively. Usually, eggs hatched in 2 days and the Cairo, Egypt. rnean percentage hatch was 8l% for 14 rep- a Zahar, A. R. 1973. Review of the ecology of licates containing at least 50 eggs. In larval malaria vectors in the WHO Eastern Mediterranean rearing experiments with l0 replicates of 50 Region. WHO/MAL/73.808 2l p. larvae per pan in mud slurry preparation, the Mencs, 1986 J. Ar'r. Mosq. CoNrnol Assoc. 105 mean pupation time was 10.4 days, with 8l% ReferencesCited survival. For l0 replicates using tap water, and Farid, M. A. 1940. Malaria infection in Anopheles 8 replicates of distilled water, mean pupation sergentiiin Egypt. Riv. Malariol. l9:159-161. times were 13.2 days and 15.2 days, with mean survival rates of 55% and 33%, respectively. Farid. M. A. 1956. The implications of Anopheles Although adult females were usually fed on sergentiifor malaria eradication programmes east of human blood, they also readily fed on pigeons, the Mediterranean. Bull. W.H.O. l5:821-828. mice and guinea pigs. Halawani, A. and A. A. Shawarby. 1957. Malaria in Natural mating in cages was not observed, Egypt.J. Egypt. Med. Assoc. 40:753-792. and on several occasions females were dissected Knight, K. L. and A. Stone. 1977. A catalog of the and found to be uninseminated, including mosquitoes of the world (Diptera: Culicidae). 2nd those from trials with large cages (90 cm3) con- edition. Thomas Say Found., Entomol. Soc. Am. taining over 500 adults. Artificial mating ap- 6:l-61l. pears to be necessary for colony maintenance. Ow Yang, C. K., F. L. Sta Maria and R. H. Wharton. However, as the survival and parity potential of 1963. Maintenance of a laboratory colony of the species is high under laboratory conditions, Anopheles maculatus Theobald by artificial mating. the number of females mated per generation Mosq. News 23:34-35. does not have to be great for routine colony Saliternick, Z. 1955. The specific biological charac- maintenance. teristics of Anopheles( Myzomlia) sergentii (Theo.) and We thank Dr. Adel Merdan for logistical their correlation with malaria control in Israel. support and helpful advice. Bull. Entomol. Res. 46:445-462. ATAEXEiI OF ONERSIP. NAGETIiT SO CIRCUUNOX Mrrurc-, JOURI.IALOF THESTRICil ilOSQUITOCOflTROL ASSOC 8l7l5l6l9l7 Dec. 20, 1985 Qu.rbrly 4 $ 35.mU5 r|'lmffi seu Fh, q, c@, h d m * tb, tu) Anerlcan ilosquito Control Association, Cultural Education Center' Albany, ilY 12224 lnerican hsquito Control AssociatJon,5515 t. shields Avenu€' Fresno, CA 93721'1113 herican ilosqulto Cohtrol Association, 5545 E. Shields Avenue, Fresno, CA 93727-7713 0r. Romld A. lard, Dept. [ntm, la]ter R€ed Amy Inst. of Res , lashlngbn' 0C 20307-510 ,. M=e lil otu br. c@iltu. id am. d tu4 nBr b' [email protected] n [email protected] bd6. tdb.@bqtu@dth,ttM 6btdNb.@rh@tu, tltda'tbffil P$ €d m, (ta d Mrrcrerc.oodk g frcomrtffi U tE..nott,ffi ltnnffiJ 2200 2200 ilG-ffiru.dd.'*ru 0 1935 I912 1935 t9t2 42 38 1978 1950 222 250 0 0 2200 2200 i!. I dry hd rb .rd.hmb m* byl\ ffi;fffd*iwfw" m..br.!rcco.rer.nd@nPti. | ,4 / 7 .t,^". p cat.n- Intertm Erec. otrector.