Navigation Links
West Nile virus passes from female to eggs, but less so from larvae to adults

In California Culex mosquitoes are considered to be the principle vectors of West Nile virus (WNV), which infects birds, humans, and other mammals during the summer. In addition, these mosquitoes may also serve as overwintering reservoir hosts as the virus is passed "vertically" from female mosquito to egg, then larva, and then adult.

To find out how often this happens, California researchers monitored WNV in mosquitoes in the field and in the lab, and observed how the virus is transmitted between generations and between insect stages. The results are published in the March, 2013 issue of the Journal of Medical Entomology in an article called "Experimental and Natural Vertical Transmission of West Nile Virus by California Culex (Diptera: Culicidae) Mosquitoes."

In the field, the researchers captured 934 female mosquitoes and found viral RNA in 34 of them. These 34 females then laid egg rafts, and the first-instar larvae from nine of them tested positive for the virus.

In the lab, two groups of infected females were observed, one to see how many transmitted the virus to their first-instar larvae, and the other to see how many transmitted the virus all the way to the adult stage of their progeny. Overall, transmission rates were significantly higher when measured for first-instar larvae compared with adults. In the first group, they found that 23 out of 28 infected females transmitted the virus to their larval offspring, while in the second group only two out of 25 adult offspring of infected females were found to carry the virus. This demonstrates that a considerable number of viral infections may be lost during larval development to the adult stage, but it is unclear why.

The percentage of females passing on the virus was also estimated by testing egg rafts. Interestingly, the presence of WNV in egg rafts did not ensure that the larvae would become infected. Among females transmitting to larvae, seven had negative egg rafts and positive larvae, and one had a positive egg raft and negative larvae. One possible explanation is that larvae may acquire the virus by feeding on infected egg rafts after emerging.

The authors conclude that future studies are needed to explain how WNV is vertically transmitted, if larvae can become infected by feeding on infected eggs, and why the virus seems to be frequently degraded during metamorphosis.

"This could be used as a tool for identifying foci of virus transmission during the WNV season," said Brittany Nelms, one of the authors of the study. "Although we found that the virus is lost from the larval to the adult stage, we can still identify areas where vertical transmission is taking place in nature."


Contact: Brittany M. Nelms
Entomological Society of America

Related biology news :

1. New device better traps viruses, airborne pathogens
2. Influenza study: Meet virus new enemy
3. Inspiring teens with research virus: Expert-mentored bioscience contest proves a powerful vector
4. Novel coronavirus well-adapted to humans, susceptible to immunotherapy
5. Avoiding virus dangers in domesticating wild plants for biofuel use
6. Newly identified natural protein blocks HIV, other deadly viruses
7. Forensic pathology: tracing the origin of the Usutu Virus
8. Spanish researchers design biomarkers for the detection of dengue and West Nile virus
9. Retrovirus in the human genome is active in pluripotent stem cells
10. Researchers show how cells DNA repair machinery can destroy viruses
11. Recent study suggests bats are reservoir for ebola virus in Bangladesh
Post Your Comments:
(Date:11/30/2015)... Nov. 30, 2015  BIOCLAIM announced today that ... year,s Fierce Innovation Awards:  Healthcare Edition, an awards ... , FierceHealthcare , and ... finalist in the category of "Privacy and Cybersecurity." ... --> Photo - ...
(Date:11/26/2015)... 2015 Research and Markets ( ) ... Sensors - Technology and Patent Infringement Risk Analysis" ... --> Fingerprint sensors using capacitive technology ... fingerprint sensor vendor Idex forecasts an increase of 360% ... devices and of the fingerprint sensor market between 2014 ...
(Date:11/20/2015)... NXTD ) ("NXT-ID" or the ... mobile commerce market and creator of the Wocket® smart ... recently interviewed on The RedChip Money Report ... on Bloomberg Europe , Bloomberg Asia, Bloomberg Australia, ... NXTD ) ("NXT-ID" or the "Company"), a biometric authentication ...
Breaking Biology News(10 mins):
(Date:11/30/2015)... , Nov. 30, 2015  Champions Oncology, Inc. ... and services to personalize the development and use of ... Chief Executive Officer, will be presenting at the LD ... 4:30pm Pacific Standard Time (PST).  The conference, held at ... Los Angeles, CA , will feature 200 small/micro-cap ...
(Date:11/30/2015)... Human Longevity, Inc. (HLI), the genomics-based, technology-driven ... Genomics, Inc., a leading genome informatics company offering highly ... The San Diego -based company has ... and Co-founder, Ashley Van Zeeland , Ph.D., who is ... of the deal were not disclosed. ...
(Date:11/30/2015)... Florida , November 30, 2015 ... specializing in the development of innovative peptide and gene-based ... metastatic disease, today announced it will be presenting at ... on December 1, 2015 at 2.30 PM PT. Dr. ... and Strategic Advisor will be giving the presentation and ...
(Date:11/30/2015)... -- HUYA Bioscience International, the leader in accelerating global development ... announced it has signed a Memorandum of Understanding with ... between KDDF and HUYA with the ultimate goal of ... the global market. China,s ... preclinical and clinical stage compounds. The company advances the ...
Breaking Biology Technology: