Showing posts with label Aedes aegypti. Show all posts
Showing posts with label Aedes aegypti. Show all posts

Wednesday, 21 September 2016

The reach of Aedes aegypti in Queensland, Australia...

I made this, based on the State of Queensland,(Queensland Health) map from the 2015-2020 Queensland Dengue Management plan.[1] 

Feel free to use this image but please abide by the copyright 
notice found within the 2015-2020 Queensland Dengue management plan.[1]
Click on map to enlarge.
The map may be a useful accompaniment to the recent paper confirming Aedes aegypti is the most likely mosquito vector of Zika virus (ZIKV) in Australia.[2]

While Australia does have these mozzies, it does not have local ZIKV transmission and Dengue is not endemic in Queensland. 

Annual local outbreaks of Dengue do occur in Queensland but these result from imported cases and are confined to north Queensland.[1]

I've added in some other map-related information to the reference section as well.[3,4,5,6]

References...

  1. 2015-2020 Queensland Dengue management plan, Queensland Government.
    https://www.health.qld.gov.au/publications/clinical-practice/guidelines-procedures/diseases-infection/governance/dengue-mgt-plan.pdf
  2. Assessment of Local Mosquito Species Incriminates Aedes aegypti as the Potential Vector of Zika Virus in Australia
    http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0004959
  3. Dengue and climate change in Australia: predictions for the future should incorporate knowledge from the past
    https://www.mja.com.au/journal/2009/190/5/dengue-and-climate-change-australia-predictions-future-should-incorporate?0=ip_login_no_cache%3D20128744c69e384fe459a669360e8b29
  4. “Dengue” mosquitoes detected in Melbourne: What does it mean?
    https://cameronwebb.wordpress.com/2014/03/16/dengue-mosquitoes-detected-in-melbourne-what-does-it-mean/
  5. The Extinction of Dengue through Natural Vulnerability of Its Vectors
    http://journals.plos.org/plosntds/article/asset?id=10.1371/journal.pntd.0000922.PDF

Monday, 25 April 2016

Biting assumptions...

This is not Aedes albopictus.
But it is a mosquito.
The Pan American Health Organization (PAHO) and the World Health Organization (WHO) Zika Epidemiological Update (status as of 21 April 2016) had some nice Zika virus (ZIKV) graphs from different - that is, not Brazil and Colombia - ZIKV affected countries.[1] 

It also had a very interesting snippet - that the Mexico Epidemiological Surveillance System (SINAVE) has reported detection of ZIKV in wild caught Aedes albopictus mosquitoes in Mexico.[1] The were identified using real-time RT-PCR and confirmed 1st April 2016.

That's a first for Mexico and also a first for the Americas in terms of detecting the variant of the Asian lineage of ZIKV that has been running rampant across the region, in a presumed vector. To date, all the detection have been from (many) humans, a howler monkey and a marmoset.[1,4,]

The 1966 Malaysian Ae.aegypti
ZIKV isolate is HQ234499 at the top
of the Asian lineage branch
The only (that I know of - please let me know if there are others) other reported detection of ZIKV from wild-caught (not lab infected) Aedes aegypti mosquitoes was a divergent virus in 1966 in Malaysia.[2,3] In that study, culture of infectious virus was also achieved. In Mexico - only ZIKV RNA was detected. It is also possible that the virus sucked up ZIKV from an infected animal or human but that these particular Ae.albopictus might not able to effectively infect other animals or humans. We'd need to know whether the mosquito testing was of whole mosquitoes or mosquito midguts, thoraces, heads, legs, saliva or salivary glands (this being the money part of the mozzie as it shows the virus infected the mosquito, left the midgut and spread, ending up in the part that will produce the infectious spit that is vomited while feeding on the animal). 

Detection in midgut only indicates ingestion whereas finding virus in the legs for example, indicates disseminated infection of the mozzies (ingested, infected, whole body spread). Whole squashed mozzies alone = more work needed. Nonetheless - this is a very valuable finding and its great to see someone is pursuing this and succeeding. And talking about it.

Up until this point we'd been assuming mosquitoes were the major transmitter because they had been in the past - as far as we knew. Now we have a little hard data.

References...

  1. http://www.paho.org/hq/index.php?option=com_content&view=article&id=11599&Itemid=41691&lang=en
  2. ISOLATION OF ZIKA VIRUS FROM AEDES AEGYPTI MOSQUITOES IN MALAYSIA
    http://www.ncbi.nlm.nih.gov/pubmed/4976739
  3. Genetic Characterization of Zika Virus Strains: Geographic Expansion of the Asian Lineage
    http://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0001477
  4. http://www.paho.org/hq/index.php?option=com_docman&task=doc_view&Itemid=270&gid=34183&lang=en