Vertical transmission of dengue virus in the Yogyakarta airport area

BACKGROUND@#International Health Regulations controls international travel including human movement, disease vector, and imported items to prevent the spread of dengue, especially in seaports, airports, and border crossing posts. This study aimed to determine dengue Transovarial Transmission Index (TTI) and distribution of dengue virus in the areas around Adisucipto Airport of Yogyakarta, Indonesia.@*METHODS@#The study was a descriptive analytic study with cross sectional design, conducted by mapping the spread of the dengue virus and identifying TTI in Adisucipto Airport. A total of 145 ovitraps were installed in both perimeter and buffer areas of the airport. Positive Ovitrap Index (OI), TTI, and serotype of dengue virus were examined. The TTI was identified using immunocytochemistry immunoperoxidase streptavidin biotin complex (IISBC) method in mosquito head squash preparations.@*RESULTS@#OI in the buffer area was 32 (45.1%), whereas OI in the perimeter area was 24 (32.4%). The TTI in the buffer and perimeter areas were 21 (18.3%) and 11 (18.9%), respectively. The TTI was found greater in the Aedes aegypti population compared to the Aedes albopictus population, both in the perimeter area (20% versus 16.7%) and the buffer area (20.3% versus 16.1%). Dengue virus serotype-2 (DENV-2) and dengue virus serotype-3 (DENV-3) were predominantly found in Ae. aegypti and Ae. albopictus.@*CONCLUSIONS@#Buffer areas of Adisucipto Airport of Yogyakarta have higher risk as breeding sites for Aedes spp., predominantly DENV-2 and DENV-3 serotypes. High OI shows that the areas are likely to have higher risk of developing dengue outbreak.

Transovarial transmission of dengue virus in Aedes aegypti : A case in Quezon City, Philippines

BACKGROUND: The changing nature of dengue epidemiology and control makes dengue one of the challenging infectious disease problems in the present time with certain inadequacies in existing knowledge base becoming apparent.OBJECTIVE: This quantitative and experimental study was conducted to provide recent local evidence that dengue virus transovarial transmission among field collected Aedes aegypti mosquitoes does occur and presents an important factor in the epidemiology and control of dengue.METHODS: Households in Quezon City, Philippines, a known dengue infection hotspot in 2011, were randomly selected (H9 and H14) for Aedes aegypti egg and larval collection. Mosquito larvae were captured using standard ovitraps and reared to adulthood in the entomology unit of the Molecular Diagnostics and Genotyping Laboratory at the University of the Philippines (UP), College of Medicine, Manila. Whole organism homogenate of adult mosquitoes were prepared for subsequent dengue virus molecular characterization and virulence testing. Both egg samples and their infection profile for dengue virus was determined by serotype specific RT-PCR.RESULTS: Molecular test results show that in each household and in each generation (parent, F1 and F2), there were detectable and strong dengue viral presence, predominantly the serotypes DEN-2, DEN-3 and DEN-4 in the Aedes aegypti mosquito homogenates.CONCLUSIONS: These laboratory evidences indicate that thransovarial transmission of dengue virus does occur in a high urban city like Quezon City where incidence of dengue is high.Thus, it is important to consider the existence of this phenomenon in existing and future dengue control programs to ensure effectiveness of community-based intervention strategies.

Preliminary findings on Bagaza virus (Flavivirus: Flaviviridae) growth kinetics, transmission potential & transovarial transmission in three species of mosquitoes.

Background & objectives: Bagaza virus (BAGV), a flavivirus synonymous with Israel turkey meningoencephalitis virus, has been found to circulate in India. BAGV has recently been held responsible for inducing febrile illness in humans and causing unusually high mortality to wild birds in Spain. A study was therefore, undertaken to determine its replication kinetics in certain mosquitoes and to determine vector competence and potential of the mosquitoes to transmit BAGV experimentally. Methods: Aedes aegypti, Culex tritaeniorhynchus and Cx quinquefasciatus mosquitoes were inoculated with BAGV; samples were harvested every day and titrated in BHK-21 cell line. Vector competence and experimental transmission were determined by examining the saliva of infected mosquitoes for virus and induction of sickness in suckling mice, respectively. Results: Cx. tritaeniorhynchus and Ae. aegypti mosquitoes yielded 5 log10 and 4.67 log10 TCID50/ml of virus on day 3 post-infection (PI), respectively while Cx. quinquefasciatus yielded a titre of 4 log10TCID50/ml on day 4 PI. BAGV was detected in saliva of all the infected mosquitoes demonstrating their vector competence. Experimental transmission of BAGV to infant mice as well as transovarial transmission was demonstrated by Cx. tritaeniorhynchus but not by Ae. aegypti and Cx. quinquefasciatus mosquitoes. Interpretation & conclusions: Replication of BAGV to high titres and dissemination to saliva in three most prevalent mosquitoes in India is of immense public health importance. Though no major outbreak involving man has been reported yet, BAGV has a potential to cause outbreaks in future.

Primer hallazgo de Aedes albopictus en el área metropolitana de Honduras / First finding of Aedes albopictus in the metropolitan area of Honduras

Se realizó un estudio descriptivo y transversal, desde agosto hasta octubre de 2009, con vistas a informar el hallazgo de Aedes albopictus en la región metropolitana de Honduras. Las muestras colectadas se llevaron al laboratorio de entomología, donde se clasificaron desde el punto de vista de la taxonomía. Se encontró asociación de esta especie con larvas de Aedes aegypti y Toxorhynchites sp. Las larvas del género Aedes fueron colocadas en bandejas blancas, luego introducidas en jaulas, a fin de obtener los adultos y corroborar el diagnóstico. Los adultos emergidos fueron clasificados de la misma forma, lo cual confirmó la presencia de Aedes albopictus en la mencionada área. Por la importancia de esta especie, se expone sobre la biología y las características principales de este vector.

A descriptive cross-sectional study was carried out from August to October 2009 in order to report the finding of Aedes albopictus in the metropolitan region of Honduras. The collected samples were taken to the entomology laboratory, where they were classified from the taxonomic point of view. There was association of this species with larvas of Aedes aegypti and Toxorhynchites sp. The larvae of the gender Aedes were placed in white trays, then they were introduced in cages, in order to obtain the adults and to corroborate the diagnosis. The obtained adults were classified in the same way, which confirmed the presence of Aedes albopictus in the mentioned area. Due to the importance of this species, it is exposed in biology with the main characteristics of this vector.