Abstracts for the Annual Meetings of the Japan Society of Medical Entomology and Zoology

Transgenic mosquitoes resistant to viral and protozoan pathogens are being developed to test the hypothesis that genetically-engineered vectors can be used to block transmission of diseases. We are focused on Aedes aegypti and the avian malaria parasite, Plasmodium gallinaceum, as a model to develop and test the basic approaches for malaria control, while Ae. aegypti also is the focus for dengue control strategies. In addition, we are working with Anopheles gambiae and the human malaria parasite, P. falciparum. We have characterized mosquito genes whose promoter sequences are candidates for controlling the expression of antipathogen effector genes, and developed stable transformation technology that will allow the integration of antipathogen genes into the vector germline. Single-chain antibodies and RNAi strategies are being pursued to produce antimalarial and antidengue effector molecules. Progress in these and other areas of genetic control will be discussed.

View full abstract

Show abstractHide abstract

Geographic information systems (GIS) and satellite imagery are increasingly applied to develop risk maps for medically important arthropod- and snail-borne diseases. Various analytical tools can be used to further interpret and analyze spatial data, and to associate environmental risk factors with probability of transmission. Clustering of arthropod vectors and snail-borne diseases occurs on scales ranging from the microhabitat to the continental levels. The occurrence of disease foci and the level of transmission depend on the spatial and temporal distribution of the vector, the pathogen and the vertebrate host(s). Examples presented will include: 1) a habitat suitability model for Lyme disease ticks in the U.S. where a GIS based statistical model was used to associate various landscape features with tick density; 2) a surveillance system for the spatial clustering and risk factors of West Nile virus in Illinois, USA, where distinct foci could be associated with urban features; 3) a space-time analysis of the distribution of Plasmodium falciparum, malariae and vivax malaria in Trinidad resulting in efficient targeting of control efforts; 4) a micro-epidemiological study of urinary schistosomiasis and Bulinus snails in coastal Kenya, where a fine spatial resolution (Ikonos) satellite image is used to construct a detailed map of household and water contact sites, and a complete distance matrix between all points in order to associate long term demographic, epidemiological, parasitological, malacological and water contact behavior data to determine spatial and temporal transmission patterns and processes. The challenge remains to relate statistical patterns and associations to the underlying biological processes.

View full abstract

Kanda and Oguma (1978) disclosed a new anopheline species, An. engarensis, in Hokkaido. Its main features were (1) an inversion, (2) frequency difference of the male clasper, and (3) incomplete presence of the humeral pale spot. There observed overlapping characters among engarensis and sinensis adults. Specimens stored in Dept. of Immunol. and Med. Zool., St. Marianna Univ., were examined thoroughly. It revealed that engarensis could be distinguished from sinensis in adult females with their 2nd or 3rd tarsal pale bands. Such morphological characters of adults are valuable in the study of population dymnamics of mosquitoes. It was expected that some combination of characters could be used effectively to identify adults of engarensis.

View full abstract

Anopheline mosquitoes were collected in July, 2002 in Hokkaido and were morphologically identified as either of sinensis, engarensis, or lesteri. However, it was frequently difficult accurately to identify morphologically. It was designed to make molecular identification at the ITS2 region of rDNA. Dried specimens of engarensis were used.
Molecular identification was successful for lesteri using the primer synthesized with the species-specific sequences at the ITS2 region. From the differences in sizes of PCR products, engarensis could be distinguished. Air-dried specimens collected in 1978 failed to give sufficient amounts of the PCR products, probably from the reason that they had been killed with ethylether vaper.

View full abstract

Register with J-STAGE for free!