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H. Ribeiro - One of the best experts on this subject based on the ideXlab platform.

Richard A. Humber - One of the best experts on this subject based on the ideXlab platform.

  • First report of Coelomomyces santabrancae sp. nov. (Blastocladiomycetes: Blastocladiales) infecting mosquito larvae (Diptera: Culicidae) in central Brazil
    Journal of invertebrate pathology, 2017
    Co-Authors: M.e. Rueda-páramo, Cristian Montalva, Walquíria Arruda, Éverton K. K. Fernandes, Christian Luz, Richard A. Humber
    Abstract:

    A project from 2013 to 2017 sought to discover pathogenic fungi and oomycetes from dipteran species that are vectors of major diseases of humans and animals in central Brazil and to begin evaluating the potential of these pathogens as potential biological control agents concentrated on mosquito larvae. Some collecting sites proved to be especially productive for pathogens of naturally occurring mosquito species and for placements of healthy sentinel larvae of Aedes aegypti in various sorts of containers in a gallery forest in the Santa Branca Ecoturismo Private Reserve of Natural Patrimony (RPPN) near Terezopolis de Goias (GO). Collections during May-April of 2016 and February 2017 yielded a few dead mosquito larvae of an undetermined Onirion sp. (Culicidae: Sabethini) whose hemocoels contained many ovoid, thick-walled, yellow-golden to golden-brown, ovoid thick-walled resistant sporangia, 38.3±4×22.8±2.3µm, decorated by numerous, closely and randomly spaced punctations of variable size and shape. These were the first indisputable collections from Brazil of any Coelomomyces species. Comparisons of the morphology of these sporangia with those of other species of Coelomomyces, confirmed that this Brazilian fungus represented a new species that is described here as Coelomomyces santabrancae.

Christopher J. Lucarotti - One of the best experts on this subject based on the ideXlab platform.

  • pathology of Coelomomyces stegomyiae in larval aedes aegypti
    Mycologia, 1998
    Co-Authors: Mahmoud Ali Shoulkamy, Christopher J. Lucarotti
    Abstract:

    Fungi in the genus Coelomomyces infect mosquito larvae and develop within the larval hem- ocoel. Larvae usually die in the fourth and final in- star, by which time, little of the larval fat body re- mains. To examine this pathology, Aedes aegypti lar- vae infected with Coelomomyces stegomyiae were chem- ically fixed, embedded in epoxy and sectioned for light microscopy. While C. stegomyiae directly invaded only cuticular epithelial cells, a number of other tis- sues were also affected. Hyphae ramified throughout the fat body in the lymphatic spaces between tropho- cytes leading to cell lysis and the depletion of the fat body. Hyphae also developed within muscle and gut tissues and in the lumen of hemopoietic organs and

  • factors affecting Coelomomyces stegomyiae infections in adult aedes aegypti
    Mycologia, 1997
    Co-Authors: Mahmoud Ali Shoulkamy, Christopher J. Lucarotti, M S T Elktatny, S K M Hassan
    Abstract:

    Coelomomyces stegomyiae usually kills its de- finitive mosquito host, Aedes aegypti, in its fourth and final larval instar. Infected larvae that survive through the pupal stage produce infected adults. The results reported here demonstrate that production of infected adults is significantly affected by larval instar and inoculum (fungal zygotes) at the time of infec- tion and rearing temperature following infection. Larvae infected at the third instar (71%) produce more infected adult mosquitoes than those infected at either first (3.7%) or second (9.0%) instars. More infected adult mosquitoes were produced from lar- vae infected at either second or third instars when these were reared at 30 C (59 and 86%) following infection as opposed to 18 (0 and 5.3%), 22 (2 and 14%) or 26 C (8.3 and 51%). Infected male and fe- male mosquito larvae were equally likely to produce infected adults.

  • Invasion of Aedes aegypti ovaries by Coelomomyces stegomyiae
    Journal of Invertebrate Pathology, 1992
    Co-Authors: Christopher J. Lucarotti
    Abstract:

    Abstract Aedes aegypti (Diptera, Culicidae) larvae, infected with Coelomomyces stegomyiae (Chytridiomycetes, Blastocladiales), can pupate and eclose to produce adults that carry the fungal infection. In female mosquitoes, fungal hyphae in the hemocoel migrate to the ovaries during the pupal stage and the first 24 to 48 hr of adult life. Hyphae penetrate the ovaries in association with epithelial cells involved in tracheole production during ovarial expansion and maturation. Infected adult female mosquitoes, that have had a blood meal, have 46% lower 20-hydroxyecdysone titers and negligible levels of vitellogenin compared to that of equivalent healthy females. Hyphae of C. stegomyiae mature to resting sporangia in the ovaries of adult Ae. aegypti in response to increased titers of 20-hydroxyecdysone which follow a blood meal. In the absence of a blood meal, maturation of hyphae to resting sporangia in infected adults was induced by injection of 20-hydroxyecdysone.

H. C. Ramos - One of the best experts on this subject based on the ideXlab platform.

Fred R. Tarver - One of the best experts on this subject based on the ideXlab platform.

  • biotic and abiotic parameters associated with an epizootic of Coelomomyces punctatus in a larval population of the mosquito anopheles quadrimaculatus
    Journal of Invertebrate Pathology, 1992
    Co-Authors: Charles S. Apperson, Fred R. Tarver, Brian A Federich, William J. Stewart
    Abstract:

    Biotic and abiotic parameters associated with an epizootic of the fungus Coelomomyces punctatus in larval populations of the mosquito Anopheles quadrimaculatus were investigated for three mosquito breeding seasons (1986-1988) in two adjacent farm ponds in North Carolina. In the first pond, the prevalence of infected larvae averaged 42% (range 0-85%) for collections made weekly from May 1 to November 20, 1986, but larvae did not occur in this pond in 1987. Infection rates in the adjacent pond, sampled during the mosquito breeding seasons of 1987 and 1988, declined from 10.9% (range 0-27.5%) in 1987 to 2.5% (range 0-14.2%) in 1988. Correlation analyses between the number of female copepods and fungal infection rates in sentinel mosquitoes were significant (P < 0.01) for Acanthocyclops robustus but insignificant for eight other species. Infections obtained in sentinel larvae placed in the ponds for 3 hr intervals indicated that C. punctatus infected larvae around sundown. Infection rates for field-collected larvae increased with the stage of larval development. However, experiments with sentinel larvae showed that early instars were more susceptible to infection than later instars, suggesting that the higher infection rates in late instars resulted from individual larvae being infected by two or more zygotes during larval development. Standard multiple regression analyses, used to determine the relationship between seasonal infection rates and water chemistry, weather variables, and the abundance of early and late instar larvae, showed that the abundance of late instars was the only independent variable common to linear models. The models only accounted for 20 and 9% of the variation in larval infection rates for 1987 and 1988, respectively. These results indicate that of the parameters examined, the seasonal abundance of the copepod, A. robustus, was the most important factor (or variable) correlated with the prevalence of mosquito infection.

  • Evidence for the copepods Acanthocyclops robustus and Mesocyclops edax as competent intermediate hosts for Coelomomyces punctatus during an epizootic in a larval population of the mosquito Anopheles quadrimaculatus.
    Journal of invertebrate pathology, 1992
    Co-Authors: Charles S. Apperson, Brian A. Federici, William J. Stewart, Fred R. Tarver
    Abstract:

    Field and laboratory experiments were conducted during an epizootic of Coelomomyces punctatus (Chytridiomycetes: Blastocladiales) in a population of the mosquito Anopheles quadrimaculatus in a North Carolina farm pond to examine the interactions of several potential copepod hosts with the mosquito and fungus. The diel vertical migratory behavior of the copepod species Acanthocyclops robustus, Eucyclops serrulatus, Macrocyclops albidus, and Mesocyclops edax were monitored in relation to infection rates in sentinel mosquito larvae. Mosquito infection occurred primarily around dusk, the same period during which A. robustus and E. serrulatus were most abundant near the surface of the pond. However, exposure of A. robustus, E. serrulatus, M. albidus, M. edax, Microcyclops varicans, and Paracyclops poppei to fungal meiospores in the laboratory showed that only A. robustus and M. edax were competent intermediate hosts for C. punctatus. Laboratory studies of the diel periodicity of gametangial dehiscence in A. robustus and M. edax infected with C. punctatus revealed that gamete release and zygote formation also occurred around dusk. The combined results of the laboratory and field studies on copepod abundance, susceptibility to infection, and periodicity of gametangial dehiscence suggest that A. robustus was the principal intermediate host for C. punctatus during the epizootic, though it is probable that M. edax also contributed importantly to the overall rate of larval infection.