Mosquitoes continued

1. 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)

2. #3 Culex pipiens/restuans • Northern house mosquito • Most likely to transmit WNV • Feeds at night on birds, humans

3. #4 Ochlerotatus japonicus • Asian bush mosquito • Currently invading state • Begins biting mid-morning, lower extremities

4. #5 Ochlerotatus triseriatus • Eastern treehole mosquito • Vector of La Cross encephalitis • Feeds at dusk on small mammals, humans to lesser extent

5. #6 Anopheles punctipennis • Mottled-wing Anopheles • Aggressive nuisance biter • Feeds during the day/dusk in shady/forested areas

6. #7 Anopheles quadrimaculatus/crucians • Common malaria mosquito (quadrimac.) • Vector of dog heartworm • Feeds during day/dusk in shady/forested areas

7. #8 Ochlerotatus trivittatus • Three-striped mosquito • Aggressive nuisance biter, especially when hot, after rain • Particularly prevalent in flooded woodlands • Feeds during the day, dusk

8. #9 Psorophora ciliata/howardii • Gallinipper • Ouch!! • Feeds during the day, at night

9. #10 Culex erraticus • Weak flier, feeds mostly on forest animals • May feed on humans when present

10. 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)

11. Most breath atmospheric air via a siphon

12. 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

13. 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

14. 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)

15. 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 • 9th leading cause of death among humans in the world (MAP) • 4th 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 children • 90% of cases are in Sub-Saharan Africa. Other hard-hit areas are: India, Brazil, Sri Lanka, Afghanistan, Vietnam and Colombia.

16. 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

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

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

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

20. 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

21. 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) • Closest known relative is a chimpanzee malaria, transferred to humans as recently as 5,000 years ago

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

23. 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

24. 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

25. 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