11-17-2011, 09:44 AM
[Crossposted with Mosquitoes & Disease discussion thread]
[I did not make it to UHH yesterday but my better half did; here are his notes, generously shared from the lecture. Please post corrections if you spot any places where these notes are inaccurate.]
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Notes from "Ecological Interactions In Avian Malaria In Hawaii"
Seminar presented by Dennis LaPointe
USGS, Kilauea Field Station, Volcano National Park
Pacific Island Ecosystems Research Center
November 16, 2011
UHH
Dennis LaPointe is an entomologist at Volcano National Park who has been instrumental in the study of avian malaria and the ecological impact on native Hawaiian and other birds.
Historically, there were 52 known Hawaiian honeycreepers on the islands. Currently 26 are extinct and 18 are endangered. Over half of the honeycreepers died due to introduced disease. In the late 1800’s, avipoxvirus was introduced to the islands with a 40% to 100% mortality of specific honeycreepers. Plasmodium relictum (avian malaria) was first reported in the red billed leiothrix in 1940 with a 63% to 90% mortality. The avian pox virus can be transmitted on surfaces but is best transferred by direct injection, therefore a mechanical vector. Avian malaria must be transferred by direct injection via mosquito bite or blood transfusion. With the decline of Hawaiian birds only 10 species remain at the lower elevations; 12 species at mid elevations; and 16 species at higher elevations.
Avian Disease System [diagram of three overlapping circles, labeled "Pathogen," "Vector," and "Host"]
Vector/Host Overlap = spatial/temporal overlap; selective host attraction; host defensive behavior
Vector/Pathogen Overlap = susceptibility vs. refractoriness; biological vs. mechanical; impacts on survivorship or fecundity
Pathogen/Host Overlap = susceptibility=resistance; immunological response=tolerance; clinical and subclinical disease
Gonotrophic Cycle/ Extrinsic Incubation (86.2 degree days)
Sporozoites (developmental stage of avian malaria pathogens) are present in the saliva of the mosquitoes, hence the injected saliva transmits the pathogen. The incubation rate of the parasite is faster at lower elevations and slower at higher elevations. The largest population of mosquitoes are at lower elevations but can be as high as 1500 feet. Temperature affects both mosquito and parasite reproduction. Temperatures of 13 degrees C and colder result in the slowest reproduction; 40 degrees and above are more ideal. At 20 degrees C, it takes 3 weeks for incubation of the parasite in mosquitoes. Transmission rates are also affected by temperature: less than 13 degrees C = no transmission; 13 to 17 degrees C = limited and seasonal transmission; and greater than 17 degrees C = seasonal to intense transmission.
Post-Pathogenic Mortality
Living Native birds: Amakihi, Iiwi, Apapane, and Maui Creeper have 63% to 90% mortality from infection
Non-Native Birds: 0% mortality; infected with the parasite indefinitely but survive and serve as carriers
Dilution Effect
Came out of Lyme disease research by Ostfield & Keesing, 2000, and Schmidt & Ostfield, 2001. Carriers decrease as number of hosts decrease; correlates to elevation. It only takes a few seconds for a mosquito to transmit the parasite to a host. A single mosquito can infect more than one host by landing on different hosts. As the relative dominance of incompetent hosts increases, the prevalence of infection decreases. Non-native birds are incompetent hosts due to their defensiveness which protects them from being bitten by mosquitoes.
Vector Competence
There are four biting mosquito species on the Hawaiian Islands. Mosquitoes breed in water; must have pools of standing water. Feral pigs create cavities that hold water in ferns the ground. Mosquitoes also reproduce in standing water pockets in lava rock. An increase in pig density results in increased numbers of cavities, hence an abundance of breeding spots for mosquitoes.
Competitive Displacement
The four species of biting mosquitoes on the islands are:
Aedes aegypti - Transmits yellow and dengue fever
Aedes albopictus – transmits dengue and malaria
Aedes japonicas – introduced in 2005; drought resistant eggs, a grazer, temperate, but does not vector avian malaria
Culex quinquefasciatus – egg rafts, water column feeder, does vector avian malaria
The native damselfly, Megalagrion calliphya, larvae are mosquito predators. The damselfly is a stream pool species that are able to control the mosquito population. Predation decreases with temperature increase, therefore a 2 degree C temperature increase due to climate change can diminish the damselfly predation affect.
More info and resources are available at these avian malaria websites:
http://biology.usgs.gov/pierc/Biocomplex...sease.html
http://en.wikipedia.org/wiki/Avian_malaria
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[End of record]
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MSP's wingsuit segment from "Seven Sunny Days"
http://www.youtube.com/watch?v=B0tU3Hy7et8&feature=related
)'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'(
[I did not make it to UHH yesterday but my better half did; here are his notes, generously shared from the lecture. Please post corrections if you spot any places where these notes are inaccurate.]
---
Notes from "Ecological Interactions In Avian Malaria In Hawaii"
Seminar presented by Dennis LaPointe
USGS, Kilauea Field Station, Volcano National Park
Pacific Island Ecosystems Research Center
November 16, 2011
UHH
Dennis LaPointe is an entomologist at Volcano National Park who has been instrumental in the study of avian malaria and the ecological impact on native Hawaiian and other birds.
Historically, there were 52 known Hawaiian honeycreepers on the islands. Currently 26 are extinct and 18 are endangered. Over half of the honeycreepers died due to introduced disease. In the late 1800’s, avipoxvirus was introduced to the islands with a 40% to 100% mortality of specific honeycreepers. Plasmodium relictum (avian malaria) was first reported in the red billed leiothrix in 1940 with a 63% to 90% mortality. The avian pox virus can be transmitted on surfaces but is best transferred by direct injection, therefore a mechanical vector. Avian malaria must be transferred by direct injection via mosquito bite or blood transfusion. With the decline of Hawaiian birds only 10 species remain at the lower elevations; 12 species at mid elevations; and 16 species at higher elevations.
Avian Disease System [diagram of three overlapping circles, labeled "Pathogen," "Vector," and "Host"]
Vector/Host Overlap = spatial/temporal overlap; selective host attraction; host defensive behavior
Vector/Pathogen Overlap = susceptibility vs. refractoriness; biological vs. mechanical; impacts on survivorship or fecundity
Pathogen/Host Overlap = susceptibility=resistance; immunological response=tolerance; clinical and subclinical disease
Gonotrophic Cycle/ Extrinsic Incubation (86.2 degree days)
Sporozoites (developmental stage of avian malaria pathogens) are present in the saliva of the mosquitoes, hence the injected saliva transmits the pathogen. The incubation rate of the parasite is faster at lower elevations and slower at higher elevations. The largest population of mosquitoes are at lower elevations but can be as high as 1500 feet. Temperature affects both mosquito and parasite reproduction. Temperatures of 13 degrees C and colder result in the slowest reproduction; 40 degrees and above are more ideal. At 20 degrees C, it takes 3 weeks for incubation of the parasite in mosquitoes. Transmission rates are also affected by temperature: less than 13 degrees C = no transmission; 13 to 17 degrees C = limited and seasonal transmission; and greater than 17 degrees C = seasonal to intense transmission.
Post-Pathogenic Mortality
Living Native birds: Amakihi, Iiwi, Apapane, and Maui Creeper have 63% to 90% mortality from infection
Non-Native Birds: 0% mortality; infected with the parasite indefinitely but survive and serve as carriers
Dilution Effect
Came out of Lyme disease research by Ostfield & Keesing, 2000, and Schmidt & Ostfield, 2001. Carriers decrease as number of hosts decrease; correlates to elevation. It only takes a few seconds for a mosquito to transmit the parasite to a host. A single mosquito can infect more than one host by landing on different hosts. As the relative dominance of incompetent hosts increases, the prevalence of infection decreases. Non-native birds are incompetent hosts due to their defensiveness which protects them from being bitten by mosquitoes.
Vector Competence
There are four biting mosquito species on the Hawaiian Islands. Mosquitoes breed in water; must have pools of standing water. Feral pigs create cavities that hold water in ferns the ground. Mosquitoes also reproduce in standing water pockets in lava rock. An increase in pig density results in increased numbers of cavities, hence an abundance of breeding spots for mosquitoes.
Competitive Displacement
The four species of biting mosquitoes on the islands are:
Aedes aegypti - Transmits yellow and dengue fever
Aedes albopictus – transmits dengue and malaria
Aedes japonicas – introduced in 2005; drought resistant eggs, a grazer, temperate, but does not vector avian malaria
Culex quinquefasciatus – egg rafts, water column feeder, does vector avian malaria
The native damselfly, Megalagrion calliphya, larvae are mosquito predators. The damselfly is a stream pool species that are able to control the mosquito population. Predation decreases with temperature increase, therefore a 2 degree C temperature increase due to climate change can diminish the damselfly predation affect.
More info and resources are available at these avian malaria websites:
http://biology.usgs.gov/pierc/Biocomplex...sease.html
http://en.wikipedia.org/wiki/Avian_malaria
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[End of record]
)'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'(
MSP's wingsuit segment from "Seven Sunny Days"
http://www.youtube.com/watch?v=B0tU3Hy7et8&feature=related
)'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'(
)'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'(
Astonishing skill! This archer is a real-life Legolas and then some!
http://geekologie.com/2013/11/real-life-...rs-anc.php
)'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'(
Astonishing skill! This archer is a real-life Legolas and then some!
http://geekologie.com/2013/11/real-life-...rs-anc.php
)'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'( )'(