Virus pathogens of Culicidae (mosquitos)

II. VIRUS PATHOGENS OF CULICIDAE (MOSQUITOS) Jessica M. Castillo Boyce Thompson Institute Tower Road, Cornell University Ithaca, New York 14853, USA and Brian A. 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C) 0 0 0 0 0 0 p4 ZC)4.1 0 C4 o 4.1 0 m) U 0 a0 0 04H 0 PK01 18 r% - o co : 0 0 0%~~~~~~~~~~~0 0 .4 4 " 0 . 0 0 U 0 44.' 04 04. o C) S C~~~~~~~) 0 44. U o o 0 "4~~ ~ ~ ~ ~ . " -44 CY~ ~~~~~~~u "40 '0 co -e 10 Pn ,4C4 '0 o" ,-44J 0 ~ ~ ~ ~ ~ ~ 0 0~~~~~~~~~~0. 0 c co "4 4 4.1~~~~~~~~$ o 0o2) 4 Z 2> a A > 0 4 44 :3 to 14 $4 c w :z go i0 tc 4 :c 44~~~~~~~~~~~~~~~~~~~~~$ 0 4eo co~4 C. 19 ABSTRACTS* Anthony, D. W. (1975). Use of viruses for control of aquatic insect pests. Environmental Protect. Agency EPA-600/3-75-100, pp. 23-39, discussion, pp. 40-47. Viruses pathogenic to mosquitos and the problems involved in their utilization as biocontrol agents are discussed. The literature on laboratory and field studies of host range, infectivity, pathogenicity, specificity, transmission and ultrastructure of the various types of viruses is briefly reviewed, including iridescent viruses (genus Iridovirus), nuclear polyhedrosis viruses (genus Baculovirus), cytoplasmic polyhedrosis, and the entomopox viruses. Arata, A. A. (1977). The developing role of microbiological agents in vector control. Experientia, 33: 125-130. Viruses are not among the major groups of anopheline pathogens that are being studied following the scheme of the World Health Organization for screening and evaluating the efficacy and safety of biological agents for control of disease vectors. *Buchatskii, L. P. (1974).. /iox virus of Aedes aegypti LJ Mikrobiol. Zhur., 36: 797-798. (In Russ.) A new virus, Entomopoxvirus aedes, is described from ultrathin sections of the infected larvae of Aedes aegypti. Buchatskii, L. P. (1975). Ziruses pathogenic for mosquitoes (Diptera, Culicidae)j Vopr. Virusol., No. 3: 268-273. (In Russ.) Literature on viruses pathogenic for mosquito species of the genera Anopheles, Culex, Uranotaenia, Orthopodonyia, Psorophora and Aedes is briefly reviewed. *Buchatskii, L. P. (1977). An iridovirus from larvae of Culiseta annulata and Culex territans. Acta Virol., 21: 85-86. Thirty 4th instar larvae of Culiseta annulata and 24 larvae of Culex territans were collected in Kiev in 1973 and found to be infected with an Iridovirus. Laboratory experiments using 130 lt instar larvae resulted in 28 and 9% infection of Cs. annulata and Cx. territans, respectively. Electron microscopic observation of MIV of the field- collected Cs. annulata showed masses of virus particles about 180 rm in diameter-in the cytoplasm. Virus particles, empty membranes and other types of inmature particles, were observed in the adipose cells. Pentagonal virus particles, 190 nm in diameter were observed in the cytoplasm of the MIV-infected Cx. territans. *Buchatskii L. P. et al. (1973). /cytoplasmic polyhedrosis virus of the Culex pipiens pipiens mosquitos=7 Med. Parazitol. Parazit. Bolezni, 42: 623-624. Larvae of Culex pipiens pipiens collected near Kiev were infected with cytoplasmic poly- hedrosis virus. Haemolymph of the infected larvae contained spherical virus particles about 60 jum in diameter and hexagonal polyhedra, 0.1-0.4jum in diameter. The virus- infected larvae were collected from water previously treated with an attractant. The low incidence of infection, which did not exceed 1%, could probably be due to stress on the mosquitos caused by the attractant. 20 Buchatskii, L. P. et al. (1976). [Sensitivity of the honeycomb moth to mosquito iridescent virus]7 Mikrobiol. Zhur., 38: 605-607. (In Ukr., Russ. and Engl. swum.) Larvae of Galleria mellonela were sensitive to mosquito iridescent virus (MIV) from Aedes cantans, but not to MIV from Ae. dorsalis, the mortalityrates being 75.9 and 8.7% respectively. Virulence of the MIV from Ae. cantans increased with passage but not the MIV from Ae. dorsalis. The possible use of G. mellonela for production of the virus is discussed. Buchatskii, L. P. & Sherban, S. D. (1976). jiome biological properties of Aedes cantans iridescent virus]7 Vopr. Virusol., No. 4: 432-435. (In Russ., Engl. aum.) The sedimentation coefficient, molecular weight and type of nucleic acid of the iridescent virus of Aedes cantans were determined. Protein analysis was done in a dissociating system using electrophoresis in a polyacrylamide gel. Buchatskii, L. P. & Sheremet, V. P. (1974). /Detection of iridescent virus of mosquitos in the Ukraine]7 Vopr. Virusol., No. 2: 226-228. (In Russ., Engl. summ.) Third and 4th instar larvae of Aedes cantans collected near Kiev in 1973 were infected with iridescent virus. Electron microscopic examination of the haemolymph of the infected larvae revealed numerous hexagonal virus particles of the R strain (RMIV). The incidence of infection was not more than 1.5-2.0%. Iridescent virus was first observed in Kazakhstan in 1970 in larvae of Aedes caspius, Ae. flavescens and Ae. stramineus, and later in Moscow in 1971, in Ae. caspius. Buchatskii., L. P., & Sheremet, V. P. (19754. LSome observation of iridescent viruses of blood sucking mosquitos (Diptera, Culicidae)J Med. Parazitol. Parazit. Bolezni, 44: 101-102. (In Russ.) Larvae of Aedes dorsalis, Ae. cantans, Culex territans and Culiseta annulata collected from Kiev and Kherson, USSR, in 1973 were found infected with iridescent virus. The incidence of infection was 1.5-2.0% with as high as 8% in some sites. Electron microscopic examination of the haemolymph showed hexagonal virus particles. Tube-like or helical particles associated with the virus were observed in infected larvae of Aedes dorsalis and Culex territans, respectively. *Buchatskii, L. P. et al. (1976X, Aiew hosts of the mosquito iridescent virus in the Ukrainian SSR and Karelian ASSRJ Mikrobipl. Zhur. 38: 502-505. (In Ukr., Russ. and Engl. sum.) Mosquito iridescent virus was isolated from larvae of Aedes cantans, Ae. dorsalis, Ae. caspius caspius, Ae. vexans, Ae. flavescens, Ae. cataphylla, Ae. excrucians, Culiseta annulata, Cs. morsitans, Culex territans and Mochlonyx velutinus (culiciformis). The ultrastructure of the virions are described and measurements of diameter of the virus particles are given. The problems of determining the nomenclature of the isolated virus are discussed. Chapman, H. C. (1974). Pathogens against mosquitoes. Proc. Tall Timbers Conf. Ecol. Anim. Contr. Habitat Mgt., Tallahassee, Fla., 5: 43-47. A sumeary is presented on the pathogens of mosquitos collected over a period of 8 years in south-western Louisiana. Eleven viruses were isolated from 23 species of mosquitos. David, W. A. A. (1975). The status of viruses pathogenic for insects and mites. Ann. Rev. Entomol, 20: 97-117. Review article, includes viruses pathogenic to mosquitos. 21 *Deshevykh, N. D. & Dzerzhinskii, V. A. (1975). /iome pathogenic microorganisms of blood-sucking mosquitoes in the Syrdar'yan food-plain] In: Markevich, A. P. (ed) ,4roblem of parasitology. Proc. Vlllth Scientific Conference of the parasitologists of the Ukrainian SSR7, Pt. 1, pp. 146-147. (In Russ.) An iridescent virus was observed in larvae of Aedes caspius. Dzerzhinskii,V. A. & Deshevykh, N. D. (1973). [On the injurious effect of iridescent virus on larvae of blood-sucking mosquitoes]7 In: Dubitskii, A. A. (ed.) Aiegulators of the number of blood-sucking flies in South Eastern Kazakhstan.7 pp. 11-17. (In Russ.). *Dzerzhinskii, V. A. et al. (1976). L«n the use of the iridovirus for the control of mosquitoes] Parazitologiya, 10: 458-459. (In Russ., Engl. summ.) Laboratory experiments were conducted in SE Kazakhstan to infect 2nd instar larvae of Aedes caspius with an iridovirus. Inoculum consisted of 50-200 mml aqueous suspensions of 10-50 infected larvae. Larval infection was observed after 4-5 days exposure to the virus. Mortality was 40-54% with 40 infected larvae as inoculum, as compared with 5-127. obtained with 10 infected larvae as inoculum. Similar levels of infection were obtained in small-scale field tests. Ermakova, G. I. (1972). [irus infection in the mosquito Aedes dorsalis (Meig.)] Vsesoyuznoi Akad. Selskokhozyaistvennkh Nauk. Doklady, 11: 36-37. (In Russ.) Ermakova, G. I. (1976). fixperiments on infection of the larvae of Culex pipiens pipiens and Aedes aegypti with viruses isolated from natural mosquito populationsj/ Probl. Vet. Sanit., 52: 3-13. (In Russ., Engl. sunm.) *Fukuda, T. & Clark, T. B. (1975). Transmission of the mosquito iridescent virus (RMIV) by adult mosquitoes of Aedes taeniorhynchus to their progeny. J. Invertebr. Pathol., 25: 275-276. Female adults of Aedes taeniorhynchus were exposed to regular type mosquito iridescent virus by injection of the virus, by topical aerosol application or per os. After exposure, the mosquitos were mated by induced copulation. Infections of the progeny were 29, 2 and 0% respectively. *Gonchar, N. M. &Buchatskii, L. P. (1974b). 5oncentration and purification of the densonucleosis virus of the mosquito Aedes aegypti Lj In: Patol. Clen. Biol. Sreds. Borby Ured. Org. Kiev, p. 51, (In Russ). *Gonchar, N. M. et al. (1974a). Zixperimental study of a virus disease of densonucleosis type in Aedes aegti LU Med. Parazitol Parazit. Bolezni, 43: 341-343. (In Russ., Engl. summ.) Up to 43% mortality of the 4th instar larvae and pupae of Aedes aegypti were obtained when crude preparations of densonucleosis virus were introduced into the natural breeding habitats of the mosquitos. The virus particles isolated from the infected larvae were about 20 nm in diameter. Pathological changes observed in some of the infected tissues of the diseased larvae are described. *Hall, D. W. & Anthony, D. W. (1976). An "R" type iridovirus from Aedes vexans (Meigen). Mosq. News,.36: 536-537. 0.3% of Aedes vexans larvae collected from Hadley, Mass., exhibited patent infection with "R" type of iridovirus. Histological studies revealed a high concentration of viral DNA in the cytoplasm of the fat body cells, the epidermis, tracheal epithelium, imaginal disc and salivary glands. The virions measured 190± 4 nm in diameter. This virus appeared to be identical to the "R" virus isolated from Ae. taeniorhynchus, in size, tissue specificity and iridescence. This is the second report of an iridescent virus which produced an orange iridescence. 22 Hembree, S. C. & Lowe, R. E. (1976). Production of gram quantities of mosquito iridescent virus. Nosg. News,36: 84-90 Laboratory methods are described for mass production, up to one gram per week, of purified regular mo*quito iridescent virus (RMIV) from larvae of Aedes taeniorhynchus. 2500 2-day old Ae. taeniorhynchus larvae exposed per os for 24 h to 50 larval equivalents of freshly triturated viral inoculum can produce about 58.9 jg of virus per infected larvae; the virus constitutes about 9.3% of the dry weight of the average infected larva. *Karpenko, L. V. et al. (1977). _Jnveatigation of the effects of densonucleosis virus on imago Aedes aegypti L. mosquitoj Med. Parazitol. Parazit. Bolegni,46: 736-741. (In Russ., Engl. sUm.) Kelly, D. C. & Tinsley, T. W. (1974). Iridescent virus replication: a microscopic study of Aedes aegypti and Antheraea eucalypti cells in culture infected with iridescent virus type 2 and 6. Microbios, 9: 75-79 Optical and electron microscopic techniques were utilized to study the cytopathic effects of the iridescent virus types 2 and 6 in the cultured cells of Aedes aegypti and Antheraea eucalypti (moth) cell lines. Observations were also made of the sequence of attachment (penetration), replication and the release of the virus from the infected cells. The pattern of morphogenesis of the two types of viruses was similar. Kononko, A. G. (1976). Ziital study of the fat body of Aedes aegypti L. mosquito larvae affected with densonucleosis virus] Med. Parazitol. Parazit. Bolezni, 45: 614-616. (In Russ., Engl. summ.) A method for staining fat body of living larvae of Aedes aegypti infected with densonucleosis virus is described. Five vital dyes, neutral red, nile blue, azure 1 and 11 and methylene blue, were found to stain the larvae without killing them. The best result was obtained with neutral red. This is a useful and rapid method fordetermining densonucleosis virus infection in living larvae. Kurstak, E. et al. (1977). Densonucleosis viruses (Parvoviridae). In: Maramorosch, K.(ed.) The Atlas of Insect and Plant Viruses. pp. 67-77. *Kuznetsova, M. 0 & Zelenko, A. P. (1975). ZA histological study of pathological chan esin Aedes aegypti L. larvae infected experimentally with mosquito densonucleosis virus. Mikrobiol. Zhur., 37: 217-220. (In Russ., Engl. suuu.) First instar larvae of Aedes aegpti were exposed in the laboratory to mosquito densonucleosis virus which had been stored for a year in 50% glycerine in phosphate buffer. The average larval mortality was 24.4% as compared to 2.7% of the untreated larvae. Descriptions are given of the histopathological changes caused by the virus in the fat body, hypodermis, Malpighian tubules and intestinal epithelium of the diseased larvae. *Lebedeva, 0. P. et al. (1973). Investigation of a virus disease of the densonucleosis type in a laboratory culture of Aedes aegypti. Acta Virol., 17: 253-256. Light microscopic examination of sections and smears of infected fat body cells of Aedes aegypti infected with a densonucleosis virus showed loose soft masses of lysed fatty tissues and cells with hypertrophied round or irregular nuclei. Electron microscopic examination of sediments from tissue homogenates showed paraspherical and hexagonal virus particles about 200nmin size. This virus resembled in size, shape and pathogenicity the densonucleosis virus described from Galleria mellonela in 1964(Vago et al. Ann. Epiphyties, 15: 473-476). 23 Lebedeva, 0. P. et al. (1975). LA rapid method for densonucleosis virus diagnosis in larvae of Aedes aegypti and its use in detecting susceptibility of insects to this virus Med. Parazitol. Parazit. Bolezni. 44: 612-615. (In Russ., Engl. summ.) Typical cytopathological changes in the fat-body cell nuclei of densonucleosis virus- infected 4th instar larvae of Aedes aegypti were detected by light microscopy from smear preparations. Using electron microscopy, typical virions from infected tissues were identified. This provides a rapid method for mass diagnosis of densonucleosis virus-caused diseases in Ae. aegypti and other insects and can be useful for survey and susceptibility studies. *Lebedinets, N. N. & Zelenko, A. P. (1975). /Infectivity of Aedes aegypti L. mosquito densonucleosis virus for larvae of other species of blood-sucking mosquitoes. Vopr. Virusol., No. 2: 192-196. (In Russ., Engl. summ.) Field collected larvae of Aedes dorsalis, Ae. vexans, Ae. cinereus and Culex pipiens pipiens were experimentally infected with densonucleosis virus isolated from Aedes aegypti. The rates of larval mortality were 36.2-88% for Ae. caspius, Ae. vexans and Ae. cinereus, with the control being 24.8-48%, and 19.1-45% for Cx. p. pipiens as compared to 3.9-6.9% for the control groups. The external symptoms of the diseased larvae and the cytopathological changes observed in the nuclei of the infected fat cells were similar to that described for the densonucleosis virus infected Ae. aegypti. Lebedinets, N. N. et al. (1976). [The effect of Aedes aegypti L. mosquito densonucleosis virus on vertebrate animalsj7 Med Parazitol. Parazit. Bolezni, 45: 95-97. The densonucleosis virus of Ae. aegypti was injected into new-born white mice and rats and observed for 1-3 months and also into chick embryos which were incubated for 2-5 days. No pathological effects or multiplication of the virions were observed in the tissues examined. Liu, I. K. M. (1975). The pathogenesis of vesicular stomatitis virus in Aedes aegypti mosquitoes. Dissert. Abstr. Intern. B. 36: 1607B. Various tissues of Aedes aegypti were observed to be capable of supporting growth of vesicular stomatitis virus (VSV) after intrathoracic injection of the virus particles into adult mosquitos. The virus persisted in appreciable amounts only in the salivary gland for more than 9 days. Electron microscopic examination showed viral particles in the cytoplasm but not in the nucleus of the cells. Virus introduced into the mosquitos per os by feeding on VSV infected mice did not persist or replicate in the mosquitos. A physical or chemical factor may be involved in the inactivation or destruction of the virus in the gut of the mosquitos. Paschke, J. D. et al. (1976). Replication of mosquito iridescent virus in Aedes aegypti cells. In: Proc. Pap. 1st Internatl. Collog. Inverteb. Pathol and IXth Ann. Meet. Soc. Invertebr. Pathol., Kingston, Canada, pp. 118-122. The stages of infection and replication of mosquito iridescent virus in the cultured cells of Aedes aegypti and the development of cytopathic effects in the virus infected cells are described in detail (see Webb et al. 1974, 1975, 1976). Paschke, J. D. & Webb, S. R. (1976). Fundamental studies on insect icosahedral cytoplasmic deoxyribovirus in continually propagated Aedes aegypti cells. In: Maramorosch, K. (ed.) Invertebrate Tissue Culture: Research Applications. pp. 269-293. 24 Payne, C. C. & Harrap, K. A. (1977). Cytoplasmic polyhedrosis viruses. In' Maramorosch, K. (ed.) The Atlas of Insect and Plant Viruses. pp. 105-112 *Service, M. W. (1977). Ecological and biological studies on Aedes cantans (Meig.) (Diptera: Culicidae) in southern England. J. Appl. Ecol., 14: 159-196. An iridescent virus was reported to cause larval mortality of Aedes cantans, ranging from 0.8% to 1.1%. *Service, M. W. & Streett, D. A. (1976). A pathogenic mosquito iridescent virus in Aedes cantans. Trans. Roy. Soc. Trop. Med. Hyg. 70:18 Mosquito iridescent virus-infected 4th instar larvae of Aedes cantans were collected in Huntingdon, England. Larval infection was about 1-2.3%. Laboratory attempts to infect healthy larvae with macerated infected tissues or purified extract of the virus were not successful. *Stoltz, D. B. et al. (1974) Virus-like particles in the mosquito Culex salinarius. J. Microscopy, 19: 109-111. The ultrastructure of the virus-like particles found in diseased larvae of Culex salinarius is described. The particles were observed to be similar to a virus-like particle causing an identical disease in larvae of Culex tarsalis in California. Topchii, M. K. et al. (1974). [n the possibilitr of transovarian transmission of the densonucleosis virus of the mosquito Aedes aepi In: Patologija Clenistonogih i Biologiceskie Sredstva Bor'bys Urednymi Organizmami. Kiev., pp. 163-164. (In Russ.) *Tsarychkova, D. B. et al. (1976). [The effect of densonucleosis virus on the imago of Aedes aegypti.7 Mikrobiol. Zhur., 38: 777-778. (In Ukr., Engl. summ.) Densonucleosis virus was observed to develop in almost all the tissues of the larvae and adults of Aedes aegypti from a laboratory colony. Cytopathological effects on the different tissues are described in detail. Veylon, R. ( 1974). Les virus relais des insecticides dans la lutte contre les insectes nuisibles et vecteurs de maladie. Les consequences possibles en pathologie humaine. Concours Mdd., Paris, 98: 2427-2430. Wagner, G. W. et al. (1974a). Proteins of two strains of mosquito iridescent virus. Intervirology, 3: 97-105. Electrophoresis technique using polyacrylamide gel and amino acid analysis were utilized to compare proteins of "R" and "T" strains of mosquito iridescent virus. Both strains have similar banding patterns consisting of nine proteins which were reduced to four in S-carboxymethylated protein preparation. The relative molecular mass of the nine proteins ranged from 15 000 to 98 000. The amino acids and tryptic peptide analyses of the RMIV and TMIV proteins indicated similar results. Wagner, G. W. et al. (1974b). A picornavirus isolated from Aedes taeniorhynchus and its interaction with mosquito iridescent virus. J. Invertebr. Pathol., 24: 380-382. A mosquito picornavirus (MPiV) was isolated from high speed supernatants of initial suspensions of MIV-infected larvae of Aedes taeniorhynchus. The purified MPiV preparation contained spherical particles with 30.2 _ 0.4 nm in diameter and contained 20% RNA, with no DNA. It was suggested that MPiV was transmitted transovarially by the continuous presence of the virus in the stock cultures of the mosquitos, although no sign or symptoms of infection were detected. The interaction of MPiV with MIV in the larvae is described. 25 Wagner, G. W. et al. (1975). Production and characterization of the cores of the "R" strain of mosquito iridescent virus. Virology, 64: 430-437. Cores of "R" strain mosquito iridescent virus (RMIV) were produced in vitro by reacting intact virus with chymotrypsin. The isolation and characterization procedures involved the use of density gradient, differential centrifugation and electrophoretic techniques. The core contained particles with diameter of 176.0 ± 6.0 nm. The density was 1.33, S20:W was 3126 and the relative molecular mass was 1.84 x 109. The isolated cores did not infect the larvae of Aedes taeniorhynchus nor the cultured cells of Aedes aegypti. A protein in the outer capsid of the virion required for attachment or penetration into the cells of the host or cultured cells was observed to be absent in the core. Wagner, G. W. & Paschke, J. D. (1977). A comparison of the DNA of the "R" and 'IT" strains of mosquito iridescent virus. Virology, 81: 298-308. The DNA of "R" and "T" strains of mosquito iridescent virus exhibited similar biophysical properties and identical nucleotide sequences, but differed in their DNA contents and relative molecular mass. RMIV contains two identical duplex DNA molecules and about 17 repetitious DNA, while TMIV has a single duplex and 30 repetitious DNA. The relative molecular masses were 243.3 x 106 and 286.7 x 10 respectively. The TMIV DNA is composed of more repeated sequences, which accounts for its higher relative molecular mass. Wagner, G. W. et al. (1977). Characterization of the top component of the "T" strain of mosquito iridescent virus. Virology, 76: 426-428 The biochemical and biophysical properties of the top component of the "T" strain mosquito iridescent virus are presented in detail. The top component particles are not infectious nor do they affect the infectivity of the virus' suspension. Webb, S. R. et al. (1974). Infection of Aedes aegypti cells with mosquito iridescent virus. J. Invertebr. Pathol., 23: 255-258. Cytopathic effects (CPE) of "R" and "T" strains of mosquito iridescent virus were similar in the infected cell lines of Singh and Peleg. CPE were observed 2.5 days after viral infection. Infected cells were characterized by formation of granules, vacuolation of the cytoplasm, aggregation of chromatin materials at the periphery of the nucleus, clustering of adjacent cells and development of distinct areas known as viroplasma. Cytoplasmic filament with refractile bodies were observed at day 3 post infection. Infected cells enlarged, became more refractile, rounded-up and detached from the substrate and were mostly floating in the medium at day 7 to 8. Virions were observed to be contained in virogenic stromas and in the adjacent cell surface and plasma membrane of the vacuoles. Cell-produced viruses were not infective to Aedes taeniorhynchus larvae nor to the two Ae. aegypti cell lines in which the virus was produced. The probable explanations and significance of the loss of infectivity as well as the lack of plaque formation by the cell-produced viruses are discussed. Webb, S. R. et al. (1975). Bioassay of mosquito iridescent virus of Aedes taenibrhynchus in cell cultures of Aedes aegypti. J. Invertebr. Pathol., 26: 205-212. The cytopathic effects of the "R" and "T" strains of mosquito iridescent virus of Aedes taeniorhynchus in Singh's and Peleg's cell lines of Aedes aegypti were similar to those previously described by Webb et al. (1974) with RMIV and ThIV of Ae. aegypti. The results indicated that Peleg's Ae. aegypti cell line was more reliable and sensitive than Singh's cells for infectivity titration of the two MIV strains. Ae. albopictus cells did not exhibit any CPE. Plaque assay attempts were not successful in the two cell lines. 26 Webb, S. R. et al. (1976). Pathology of mosquito iridescent virus of Aedes taeniorhynchus in cell cultures of Aedes aegypti. J. Invertebr. Pathol., 27: 27-40. Electron microscopic observations are presented in detail on the sequence of infection and development of cytopathic effects of the "R" and "T" strains of MIV of Aedes taeniorhynchus in Aedes aegypti in cultured cells. The initiation of attachment (penetration), replication, maturation and release of the virus from the infected cells are described. Zelenko, A. P. et al. (1977). ZOn glycerol conservation of Aedes aegypti L. mosquito densonucleosis virus]J Med. Parazitol. Parazit Bolezni 46 113-114 (in Russ.).densonucleosis~ ~ ~ ~_iu2Prztl i oen,"