Insects and Human Disease
Insects and Human Disease
Goals:Goals:
1. Define: vector, host, parasite, pathogen, disease, disease cycle, myiasis, envenomization, endemic, epidemic.
2. Know the impact of arthropod-borne disease on humans, other animals, and plants.
3. Learn current “in the news” diseases and disease cycles.
1. Define: vector, host, parasite, pathogen, disease, disease cycle, myiasis, envenomization, endemic, epidemic.
2. Know the impact of arthropod-borne disease on humans, other animals, and plants.
3. Learn current “in the news” diseases and disease cycles.
TOP 10 WAYS in which arthropods affect the health and well-being of man and animals...
TOP 10 WAYS in which arthropods affect the health and well-being of man and animals...
Tsetse fly
TOP 10 WAYSTOP 10 WAYS
3. Envenomization - toxemia - Stinging of Wasps or Biting of Spiders3. Envenomization - toxemia - Stinging of Wasps or Biting of Spiders
Brown recluse wound two years after the bite
Brown recluse wound two years after the bite
1. Annoyance - Buzzing flies or feeding mosquitoes.1. Annoyance - Buzzing flies or feeding mosquitoes.
2. Mechanical pain from bites.2. Mechanical pain from bites.
TOP 10 WAYSTOP 10 WAYS
4. Stress: · Gadding, running , or milling of animals caused by insect-induced fright or extreme annoyance
· Weight loss, loss of reproductive capacity, low milk production
4. Stress: · Gadding, running , or milling of animals caused by insect-induced fright or extreme annoyance
· Weight loss, loss of reproductive capacity, low milk production
5. Myiasis and mechanical pain associated with larval invasion of, and establishment in tissues. (Bot Flies, maggots)
5. Myiasis and mechanical pain associated with larval invasion of, and establishment in tissues. (Bot Flies, maggots)
TOP 10 WAYSTOP 10 WAYS
8. Vectoring of parasites causing diseases such as plague, malaria, yellow fever, and encephalitis
8. Vectoring of parasites causing diseases such as plague, malaria, yellow fever, and encephalitis
6. Dermatosis - dermatitis6. Dermatosis - dermatitis
7. Allergy and related conditions 7. Allergy and related conditions
TOP 10 WAYSTOP 10 WAYS
9. Vectoring of pathogens that threaten our food supply9. Vectoring of pathogens that threaten our food supply
10. Entomophobia--fear of insects or arthropods or imagined infestation10. Entomophobia--fear of insects or arthropods or imagined infestation
TOP 10 WAYSTOP 10 WAYS
KEY VOCABULARY
Pathogen: An organism that causes disease
Vector: An organism that carries a pathogen from one host to another
Host: An organism that is attacked and used as a resource by a parasite/pathogen
Infection: Invasion of a host by a pathogen
Disease: Visible signs of infection by a pathogen
Disease Cycle: The complete description of the movement of a pathogen from one host to another
KEY VOCABULARY
Pathogen: An organism that causes disease
Vector: An organism that carries a pathogen from one host to another
Host: An organism that is attacked and used as a resource by a parasite/pathogen
Infection: Invasion of a host by a pathogen
Disease: Visible signs of infection by a pathogen
Disease Cycle: The complete description of the movement of a pathogen from one host to another
Arthropods as Transmitters of Disease Agents
Arthropods as Transmitters of Disease Agents
Protozoans: Single-celled EukaryotesProtozoans: Single-celled Eukaryotes
Leishmania spp. · Leishmaniasis· Vector: sand fly
Leishmania spp. · Leishmaniasis· Vector: sand fly
Plasmodium spp. · Malaria· Vector: mosquitoes
Plasmodium spp. · Malaria· Vector: mosquitoes
Trypanosoma spp. · Human sleeping sickness, Chaga’s disease· Vectors: Tsetse Fly and Assassin Bug
Trypanosoma spp. · Human sleeping sickness, Chaga’s disease· Vectors: Tsetse Fly and Assassin Bug
ProtozoansProtozoans
Fig. 20.23, p. 324
sporozites
3 Sporozites asexually reproduce in liver cells.
merozoite
4 Offspring (merozoites) enter blood, invade red blood cells, reproduce asexually. They can do so often, over a prolonged period. Disease symptoms (fever, chills, shaking) get more and more severe.
5 Some of the merozoites enter liver, cause more malaria episodes.
6 Others develop into male, female gametocytes, that are released into bloodstream.
male gametocyte in red blood cell
sporozoite
2 Mosquito bites human, bloodstream carries sporozoites to liver.
1 In the gut of a female mosquito carrying the malarial parasite Plasmodium, zygotes of the parasite develop into sporozoites, which migrate to her salivary gland.
7 Female mosquito bites, sucks blood from infected human. Gametocytes in blood enter her gut, mature into gametes which fuse to form zygotes.
ProtozoansProtozoansMalaria Disease Cycle
Helminths (Flatworms): · Multicellular parasites, · Complex life cycles, multiple hosts
· Trematodes (flukes) and Cestodes (tapeworms)
·Arthropods may serve as intermediate hosts for these parasites
Helminths (Flatworms): · Multicellular parasites, · Complex life cycles, multiple hosts
· Trematodes (flukes) and Cestodes (tapeworms)
·Arthropods may serve as intermediate hosts for these parasites
Fluke
60 ft from
head to tail
60 ft from
head to tail
HelminthsHelminths
Filarisis world distribution
Elephantiasis
Filariasis and Elephantiasis· Vector: mosquitoes
Filariasis and Elephantiasis· Vector: mosquitoes
NematodesNematodesNematodes (Roundworms)· Multicellular parasites, complex life cycles· Filarial nematodes are major parasites
Nematodes (Roundworms)· Multicellular parasites, complex life cycles· Filarial nematodes are major parasites
Onchocerciasis (river blindness)· Vector: Black Fly
Onchocerciasis (river blindness)· Vector: Black Fly
NematodesNematodes
Heart Worm· Vector: Mosquito
Heart Worm· Vector: Mosquito
NematodesNematodes
Viruses: Non-cellular infectious agentsViruses: Non-cellular infectious agents
Yellow Fever· Vector: Aedes aegypti Mosquito· No cure
Yellow Fever· Vector: Aedes aegypti Mosquito· No cure
VirusesViruses
Dengue (breakbone) Fever· Vector: Aedes aegypti Mosquito· No cure
Dengue (breakbone) Fever· Vector: Aedes aegypti Mosquito· No cure
VirusesViruses
West Nile Virus – Flavivirus· Single stranded RNA· Virus found in Africa, West Asia, Middle East.·Imported in USA in the summer of 1999· Vector: Culex mosquitoes· No cure
West Nile Virus – Flavivirus· Single stranded RNA· Virus found in Africa, West Asia, Middle East.·Imported in USA in the summer of 1999· Vector: Culex mosquitoes· No cure
VirusesVirusesWest Nile Virus
- Most cases with no symptoms or mild flu-like symptoms
- Inflammation of brain (encephalitis)
- 13,491 cases and 533 deaths by Jan 1, 2004.
- Most cases with no symptoms or mild flu-like symptoms
- Inflammation of brain (encephalitis)
- 13,491 cases and 533 deaths by Jan 1, 2004.
- Survival- Without symptoms but infected - Neurologic disease- Limb incoordination- Death
VirusesVirusesWest Nile Virus
· 30% exhibit any noticeable symptoms
· Less than 1% of these cases become life-threatening
· Most people have mild, flu-like symptoms, or no symptoms at all.
· Most susceptible are the elderly and those with compromised immune systems.
· West Nile Virus is not transmissible from person to person.
· 30% exhibit any noticeable symptoms
· Less than 1% of these cases become life-threatening
· Most people have mild, flu-like symptoms, or no symptoms at all.
· Most susceptible are the elderly and those with compromised immune systems.
· West Nile Virus is not transmissible from person to person.
Updated 11/08/2002 2:00 PM497 Cases of Human West Nile Virus in Michigan41 Total Deaths in Michigan
Updated 11/08/2002 2:00 PM497 Cases of Human West Nile Virus in Michigan41 Total Deaths in Michigan
VirusesVirusesWest Nile Virus
Cases by Age and Sex
Age Female Male Unknown Total
Unknown 2 1 3
0 to 18 5 8 13
19 to 65 125 151 276
Age 65+ 83 121 1 205
Total 215 281 1 497
% Female or Male 43.3% 56.5% 0.20%
VirusesViruses
West Nile Virus- 2003West Nile Virus- 2003
West Nile Virus
VirusesVirusesWest Nile Virus
WNV- 2002 BirdsWNV- 2002 Birds
West Nile Virus VirusesViruses
WNV- 2003 BirdsWNV- 2003 Birds
VirusesVirusesWest Nile Virus
WNV- 2002 HumansWNV- 2002 Humans
VirusesVirusesWest Nile Virus
WNV- 2003 HumansWNV- 2003 Humans
WNV 2002 to 2003 in MI: What was different???WNV 2002 to 2003 in MI: What was different???
VirusesVirusesWest Nile Virus
West Nile Virus- 2002West Nile Virus- 2002 West Nile Virus- 2003West Nile Virus- 2003
Encephalitides- (Eastern Equine Encephalitides, St. Louis , and Western Encephalitides)
· Vector: Mosquito
Encephalitides- (Eastern Equine Encephalitides, St. Louis , and Western Encephalitides)
· Vector: Mosquito
VirusesViruses
Eastern Equine Encephalitis – MICHIGAN!
·Vector: Mosquito- Culiseta melanura·Symptoms: fever, joint pain·Treatment: none
Eastern Equine Encephalitis – MICHIGAN!
·Vector: Mosquito- Culiseta melanura·Symptoms: fever, joint pain·Treatment: none
Pathogenic in both mosquitoes and birds
•virus sometimes leaves swamp setting and is transmitted to horses, game birds (penned pheasants), and people
•highly pathogenic in these “dead-end” hosts
•outbreaks occurred in the early 1940’s, 1973, 1980-83, 1989 and 1991
•Most serious mosquito borne disease in Michigan
Bacteria: Single-celled prokaryotesBacteria: Single-celled prokaryotes
BacteriaBacteria
Rocky Mountain Spotted Fever and Colorado Tick Fever (Rickettsia spp.)
· Vector: Tick · Seasonal transmission· Antibiotics are effective
Rocky Mountain Spotted Fever and Colorado Tick Fever (Rickettsia spp.)
· Vector: Tick · Seasonal transmission· Antibiotics are effective
BacteriaBacteria
BacteriaBacteria
Epidemic Typhus (Rickettsia spp.)
· Vector: Human body louse · Seasonal transmission· Hygiene-dependent· Antibiotics are effective
Epidemic Typhus (Rickettsia spp.)
· Vector: Human body louse · Seasonal transmission· Hygiene-dependent· Antibiotics are effective
Western vector
Eastern vector
Bubonic Plague (Yersinia pestis)· Vector: Flea· Can be transmitted person-person· Two forms – both with high mortality· Treatment must be rapid, with powerful antibiotics
Bubonic Plague (Yersinia pestis)· Vector: Flea· Can be transmitted person-person· Two forms – both with high mortality· Treatment must be rapid, with powerful antibiotics
BacteriaBacteria
http://www.cehs.siu.edu/fix/medmicro/yersi.htm
Plague (Yersinia) distribution Plague (Yersinia) distribution
BacteriaBacteria
Tularemia (Rabbit fever) Francisella tularensis
Transmitted by:· Ticks, deer flies· Direct inoculation from skinning rabbits· Inhalation
Symptoms:· Skin ulcers, swollen lymph glands, inflamed eyes, sore throat, diarrhea or pneumonia. · Can be fatal without treatment (antibiotics)
Tularemia (Rabbit fever) Francisella tularensis
Transmitted by:· Ticks, deer flies· Direct inoculation from skinning rabbits· Inhalation
Symptoms:· Skin ulcers, swollen lymph glands, inflamed eyes, sore throat, diarrhea or pneumonia. · Can be fatal without treatment (antibiotics)
BacteriaBacteria
Borrelia burgdorferi
BacteriaBacteria
http://www-2.cs.cmu.edu/afs/cs.cmu.edu/user/jake/mosaic/lyme.htmlIxodes scapularis
Lyme Disease (Borrelia burgdorferi)
·Vector: Deer ticks, Lone star tick·Symptoms: Bulls-eye rash, fever, joint pain·Treatment: Antibiotics, long term care
Lyme Disease (Borrelia burgdorferi)
·Vector: Deer ticks, Lone star tick·Symptoms: Bulls-eye rash, fever, joint pain·Treatment: Antibiotics, long term care
Lyme Disease –Borrelia burgdorferi
• The tick feeds on small rodents, deer and man.
• In 1991, Michigan reported 46 cases of Lyme Disease, based on the new case definition. Michigan has reported 542 Lyme disease cases from 1982 to 2000 (only one case was reported in 1999, and none in 2000)
Lyme Disease –Borrelia burgdorferi
• The tick feeds on small rodents, deer and man.
• In 1991, Michigan reported 46 cases of Lyme Disease, based on the new case definition. Michigan has reported 542 Lyme disease cases from 1982 to 2000 (only one case was reported in 1999, and none in 2000)
BacteriaBacteria
Vectors: The VehicleVectors: The Vehicle
Key Vector attributes:
· Proximity to host(s)
· Mobility
· Faithful transmission to host
· Minimal harm from pathogen
Key Vector attributes:
· Proximity to host(s)
· Mobility
· Faithful transmission to host
· Minimal harm from pathogen
Mosquitoes (Family Culicidae)
Several species of mosquitoes bite man and animals in Michigan. Some species develop in pools while others develop in ponds and marshes. Occur during the spring and summer in Michigan.
Mosquitoes (Family Culicidae)
Several species of mosquitoes bite man and animals in Michigan. Some species develop in pools while others develop in ponds and marshes. Occur during the spring and summer in Michigan.
VectorsVectors
Black Flies (Family Simuliidae)
Immatures occur in clear streams with high oxygen concentration, and the adults emerge during late May and June, mainly in the Upper Peninsula.
Black Flies (Family Simuliidae)
Immatures occur in clear streams with high oxygen concentration, and the adults emerge during late May and June, mainly in the Upper Peninsula.
Bite mark
VectorsVectors
Stable Flies (Family Muscidae)
Spoiled feed or hay mixed with wastes from horses and other livestock on farms or in stables. Upper Peninsula of Michigan, particularly Porcupine Mountains and along Lake Superior beaches.
Stable Flies (Family Muscidae)
Spoiled feed or hay mixed with wastes from horses and other livestock on farms or in stables. Upper Peninsula of Michigan, particularly Porcupine Mountains and along Lake Superior beaches.
VectorsVectors
Deer and Horse Flies (Family Tabanidae)
Swamps and marshes, along stream banks and ponds and lakes.
Deer and Horse Flies (Family Tabanidae)
Swamps and marshes, along stream banks and ponds and lakes.
VectorsVectors
Life stages of deer tick
Life stages of dog tick
Ticks (Family Ixodidae)
Until the discovery of Lyme disease and the deer tick, lxodes scapularis (formerly dammini), in Michigan, the American dog tick (Dermacentor variabilis) was the most pestiferous tick in Michigan. Both of these ticks are more abundant in the Upper Peninsula.
Ticks (Family Ixodidae)
Until the discovery of Lyme disease and the deer tick, lxodes scapularis (formerly dammini), in Michigan, the American dog tick (Dermacentor variabilis) was the most pestiferous tick in Michigan. Both of these ticks are more abundant in the Upper Peninsula.
VectorsVectors
VectorsVectors
VECTOR MANAGEMENTVECTOR MANAGEMENT
EliminateHabitats
Eliminateexposure
Insecticides
Vaccine development
Photo: TEK/SPL/Photo Researchers
VectorsVectors
VectorsVectors
Transmit bacterial pathogens to plantsTransmit bacterial pathogens to plants
Transmit viral pathogens to potatoTransmit viral pathogens to potato
Potato AphidPotato Aphid
http://www.inra.fr/Internet/Produits/HYPPZ/RAVAGEUR/6aulsol.htm#ima
Glassy WingedSharpshooterGlassy WingedSharpshooter
http://botfly.ifas.ufl.edu/index.htm
Bot Flies – Yummy Bot Flies – Yummy
Human BotHuman Bot
Direct PestsDirect Pests
Direct PestsDirect Pests
Review Tuesday
Test Thursday
Review Tuesday
Test Thursday
