Mosquitoes continued Announcements Speakers for today: Chris Gibson (malaria) and Sarah Stephan (dengue) On Deck: Natalie Popham Quiz Next Tuesday – Covers chapters 12, 13 & 14 (Biting Midges, Black Flies, Mosquitoes)

#3 Culex pipiens/restuans Northern house mosquito Most likely to transmit WNV Feeds at night on birds, humans

#4 Ochlerotatus japonicus Asian bush mosquito Currently invading state Begins biting mid-morning, lower extremities

#5 Ochlerotatus triseriatus Eastern treehole mosquito Vector of La Cross encephalitis Feeds at dusk on small mammals, humans to lesser extent

#6 Anopheles punctipennis Mottled-wing Anopheles Aggressive nuisance biter Feeds during the day/dusk in shady/forested areas

#7 Anopheles quadrimaculatus/crucians Common malaria mosquito (quadrimac.) Vector of dog heartworm Feeds during day/dusk in shady/forested areas

#8 Ochlerotatus trivittatus Three-striped mosquito Aggressive nuisance biter, especially when hot, after rain Particularly prevalent in flooded woodlands Feeds during the day, dusk

#9 Psorophora ciliata/howardii Gallinipper Ouch!! Feeds during the day, at night

#10 Culex erraticus Weak flier, feeds mostly on forest animals May feed on humans when present

Generic Mosquito Life Cycle Larvae are wigglers Pupae are tumblers (quite active) Both breath air Eggs are laid on the surface of water in rafts (Culex) or singly (Anopheles) or near water (Aedes)

Most breath atmospheric air via a siphon

Mosquito Diet Most Larvae feed on algae but a few are predaceous and feed on other mosquito larvae Only females are blood sucking Males and females feed on nectar and other plant juices

After Emergence … Day 1 – Rest on nearest available moist/shady spot. Vertical surfaces. Day 2 – Carbohydrate feeding Day 2/3 – First blood meal Next Day – First egg clutch After egg clutch, more carbohydrate & blood meals Typical adult lives 7 – 10 days

Mosquitoes and Disease Malaria Nematodes (Filariasis) Viruses with Hemorrhagic Forms –Yellow Fever –Dengue –Rift Valley Fever Encephalitis (Encephalomyelitis) Viruses –Western Equine Encephalitis (WEE) –Eastern Equine Encephalitis (EEE_ –St. Louis Encephalitis (SLE) –Venezuelan Equine Encephalitis (VEE) –West Nile Virus (WNV) –La Crosse Encephalitis (LCE) –Japanese Encephalitis Virus (JEV)

Malaria “mala” “aria” – bad air One of the most widespread human disease –Approximately 700 million current have the disease –Roughly ¼ of humans are currently at risk –9 th leading cause of death among humans in the world (MAP)MAP –4 th leading cause of death among children <5 world wide (WHO, 2005), 3 times that of accident/injuries –Number 1 cause of death among children in the tropics. –1 – 3 million people die from malaria each year (NAID, 2009), mostly childrenNAID, 2009 –90% of cases are in Sub-Saharan Africa. Other hard-hit areas are: India, Brazil, Sri Lanka, Afghanistan, Vietnam and Colombia.

Malaria is transmitted by Anopheles mosquitoes The principal genus in the Anophelinae The other Subfamily are the Culicinae Species can be distinguished by eye very easily based on how the larvae float, how the adults rest, how the adult head appears

Anopheles vs. Culicine mosquitoes – Adult Resting Behavior Anopheles Adult Culicine Adult

Anopheles vs. Culicine mosquitoes – Larval Resting Behavior Anopheles larva at rest Culicine larva at rest

Anopheles vs. Culicine mosquitoes – Head Shape Anopheles Mouth Parts Culicine Mouth Parts

Malaria Parasite Protozoa in the genus Plasmodium. 5 spp, Each causes its own form of malaria, each is transmitted by its own mosquito complex Fevers that they cause are classified by their recurrent frequency (AKA paroxysms) –Quotidian: Recurrent fever every 24 hours –Tertian: Every 48 hours –Quartan: Every 72 hours

P. falciparum Causes “Malignant tertian malaria” –tertian malaria is a recurrent fever (paroxysm) every 2 days Most dangerous form of malaria 90% of cases and deaths world wide. Global in distribution (see MAP) MAP Closest known relative is a chimpanzee malaria, transferred to humans as recently as 5,000 years ago

P. vivax Causes “Benign Tertian Malaria” 2 nd most common Rarely fatal Mostly in Asia & Latin America Mature P. vivax schizont

P. malariae Causes “Quartan Malaria” –Paroxysm every 3 days –Persists for a very long time, life-time is common –Almost never fatal World wide distribution Can be misdiagnosed with P. knowlesi

P. ovale Causes a benign tertian malaria similar to P. vivax but with a long-lived recurrent form similar to P. malariae. Mostly limited to W. Africa but is spreading. Plasmodium ovale trophozoite

P. knowlesi Causes a Quotidian Fever –Paroxysm every 24 hours Non-relapsing, case mortality ~2% First found in a human in 1965, Malaysia. Second case in 1971 Has been growing rapidly since 2004 Now accounts for up to 70% of cases in Malaysia, neighboring countries reporting cases