Culicinae Mosquitoes Overview
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Questions and Answers

Which mosquito genus is known to be a vector for both Japanese encephalitis and filariasis?

  • Culex (correct)
  • Aedes
  • Mansonia
  • Haemagogus

    • Which mosquito genus is known to predate on other insects?

  • Sabethes
  • Aedes
  • Coquillettidia
  • Psophora (correct)

    • Which mosquito genus lays eggs in rafts on the water surface?

  • Aedes
  • Sabethes
  • Culex (correct)
  • Mansonia

    • Which mosquito genus is known to breed in tree holes and bamboo stumps?

    <p>Haemagogus (D)</p> Signup and view all the answers

    Which mosquito genus is primarily active during the day and rests outdoors?

    <p>Aedes (B)</p> Signup and view all the answers

    Which mosquito genus is a major vector for dengue fever?

    <p>Aedes (B)</p> Signup and view all the answers

    Which of the following is NOT a control strategy used for Aedes mosquitoes?

    <p>Expanded polystyrene beads (A)</p> Signup and view all the answers

    Which mosquito genus is known for its distinctive black and white patterns on its thorax, legs, and abdomen?

    <p>Aedes (B)</p> Signup and view all the answers

    Which mosquito genus is found mainly in tropical regions and is known to attach its larvae to aquatic plants for breathing?

    <p>Mansonia (D)</p> Signup and view all the answers

    Which of the following is NOT a commonly used insecticide for controlling Culex mosquitoes?

    <p>Bacillus thuringiensis israelensis (Bti) (B)</p> Signup and view all the answers

    Which of the following is NOT a major vector for filariasis?

    <p>Sabethes (C)</p> Signup and view all the answers

    Which mosquito genus is the main vector for onchocerciasis (river blindness) in Africa?

    <p>Simulium (B)</p> Signup and view all the answers

    Which of the following is a control strategy for Mansonia mosquitos?

    <p>Weed removal (D)</p> Signup and view all the answers

    Which of the following is NOT a form of filariasis?

    <p>Onchocerciasis (C)</p> Signup and view all the answers

    Which of the following is an example of a larvicide used for controlling mosquito populations?

    <p>Methoprene (C)</p> Signup and view all the answers

    What is the primary reason why males have larger lenses in the upper half of their eyes?

    <p>To enhance their visual acuity when flying (A)</p> Signup and view all the answers

    Which of these is NOT a characteristic of black fly larvae?

    <p>They feed on algae and other aquatic organisms. (A)</p> Signup and view all the answers

    What is the most common method used by black flies to deposit their eggs?

    <p>Females lay their eggs in sticky masses on rocks, vegetation, or other surfaces near water. (A)</p> Signup and view all the answers

    Which one of these is NOT a feature of the black fly's wing structure?

    <p>Wings have a distinctive pattern of scales and hairs. (A)</p> Signup and view all the answers

    What is the primary distinguishing characteristic of a black fly's tarsi (feet)?

    <p>They have a pair of sharp claws for clinging to surfaces. (D)</p> Signup and view all the answers

    What is the most common symptom of onchocerciasis (river blindness) in the skin?

    <p>Thickening and disfigurement. (D)</p> Signup and view all the answers

    How are black flies primarily controlled at the community level?

    <p>Reducing breeding sites and treating larvae. (C)</p> Signup and view all the answers

    Which of the following is a commonly used insecticide for controlling black fly larvae?

    <p>Bacillus thuringiensis israelensis (Bti) (A)</p> Signup and view all the answers

    Which of these plays a significant role in the transmission cycle of onchocerciasis?

    <p>All of the above are important in the transmission cycle. (D)</p> Signup and view all the answers

    What is the primary method used to treat onchocerciasis?

    <p>Antiparasitic drugs to kill microfilariae. (C)</p> Signup and view all the answers

    Flashcards

    Holoptic Eyes

    Eyes that touch each other, commonly seen in males.

    Short Antennae

    Males have short, 11-segmented, cylindrical antennae.

    Biting Mechanism

    Labrum stretches skin; mandibles scrape and rupture capillaries.

    Black Fly Eggs

    Black or brown triangular eggs laid in flowing water.

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    Larvae Habitat

    Cylindrical larvae attach to rocks in fast-flowing rivers.

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    Onchocerciasis

    Disease caused by the Onchocerca volvulus, transmitted by black flies.

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    Transmission Cycle

    Infected flies inject larvae into humans, who then become hosts.

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    Preventive Measures

    Use insect repellents, wear protective clothing, and avoid infested areas.

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    Community Control

    Reduce breeding sites and apply insecticides.

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    Mass Drug Administration (MDA)

    Annual treatment with Ivermectin to combat microfilariae.

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    Culicinae mosquitoes

    A subfamily of mosquitoes with 40 genera, including several vectors for diseases.

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    Culex mosquitoes

    Mosquitoes that breed in polluted water and bite at night; vectors for filariasis and Japanese encephalitis.

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    Aedes mosquitoes

    Mosquitoes known for their black and white patterns, breeding in containers, and daytime biting; vectors for yellow fever and dengue.

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    Haemagogus mosquitoes

    Mosquitoes found in Central and South America, breeding in tree holes, biting during the day, and vectors for yellow fever.

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    Sabethes mosquitoes

    Mosquitoes that breed in tree holes and canopies in Central and South America and are vectors for yellow fever.

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    Mansonia mosquitoes

    Mosquitoes that breed in swamps and marshes at night and are vectors for filariasis.

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    Coquillettidia mosquitoes

    Mosquitoes that breed in plants, which are vectors for filariasis; found in tropical regions.

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    psophora mosquitoes

    Mosquitoes found mainly in the Americas, breed in flooded pastures but are not major disease vectors.

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    Yellow fever

    A viral disease transmitted by Aedes mosquitoes, primarily affecting Africa and tropical Americas.

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    Dengue

    A viral infection affecting worldwide populations, transmitted mainly by Aedes mosquitoes with no animal reservoir.

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    West Nile virus

    A viral infection transmitted by Culex mosquitoes, with birds as the primary reservoir.

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    Filariasis

    A parasitic disease caused by Wuchereria bancrofti and Brugia malayi, transmitted by several mosquito types.

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    Culex control methods

    Methods including sanitation improvement, insecticides, and suffocating larvae in pits to control Culex mosquitoes.

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    Aedes control strategies

    Control methods including source reduction, larvicides, and vaccination to manage Aedes mosquitoes.

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    Control of filariasis

    Involves Mass Drug Administration and insecticide-treated bed nets to prevent infection.

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    Study Notes

    Culicinae Mosquitoes

    • Subfamily contains 40 genera
    • Important genera include Culex, Aedes, Haemagogus, Sabethes, Mansonia (medically significant). Others include Coquillettidia, Psorophora (less significant).
    • Many are disease vectors, including yellow fever, dengue, filariasis, and arboviruses.

    Culex Mosquitoes

    • Found worldwide except extreme northern regions.
    • Lay eggs in rafts (300 eggs) on water surfaces.
    • Larvae have a long siphon with multiple subventral hair tufts.
    • Adults have brown scales, simple tarsal claws, and a blunt abdomen tip.
    • Breed in polluted water (drains, septic tanks, ditches).
    • Vector of filariasis (Wuchereria bancrofti, Japanese encephalitis).
    • Bites at night (nocturnal) and rests indoors/outdoors.

    Aedes Mosquitoes

    • Found worldwide, including arctic regions.
    • Lay black eggs singly on damp surfaces (can withstand drying).
    • Larvae have short siphons and one subventral hair tuft.
    • Adults have distinctive black and white patterns on thorax, legs, and abdomen.
    • Breed in container habitats (tree holes, tires, pots, water storage).
    • Vector of yellow fever, dengue, chikungunya.
    • Bites during the day and rests outdoors.

    Haemagogus Mosquitoes

    • Found in Central and South America.
    • Breed in tree holes and bamboo stumps.
    • Bites during the day, mostly in treetops.
    • Vector of yellow fever.

    Sabethes Mosquitoes

    • Found in Central and South America.
    • Breed in tree holes, bamboo, bromeliads.
    • Bites during the day, mainly in the canopy.
    • Vector of yellow fever.

    Mansonia Mosquitoes

    • Found mainly in tropical regions.
    • Lay eggs under floating vegetation.
    • Larvae attach to aquatic plants to breathe.
    • Breed in swamps, marshes, ponds.
    • Bites at night and rests outdoors.
    • Vector of Brugia malayi filariasis.

    Coquillettidia Mosquitoes

    • Found mainly in tropical and some temperate regions.
    • Larvae attach to plants (similar to Mansonia).
    • Vector of Brugia malayi filariasis.

    Psorophora Mosquitoes

    • Found mainly in North, Central, and South America.
    • Breed in flooded pastures and rice fields.
    • Some species are predatory.
    • Not major disease vectors but aggressive biters.

    Medical Importance of Culicinae Mosquitoes

    • Many cause severe biting in tropical and temperate regions.
    • Large-scale control operations exist to reduce nuisance.

    Yellow Fever

    • Regions: Africa and tropical Americas.
    • Transmission:
      • Sylvatic (forest): Monkey-to-monkey via Aedes africanus.
      • Rural (edge of forest): Monkey and human via Aedes bromelia, Aedes luteoceohalus.
      • Urban (cities): Human-to-human via Aedes aegypti.
    • Vectors: Aedes (Africa, Americas), Haemagogus, and Sabethes (Americas).
    • Control: Vaccination (17D mosquito).

    Dengue

    • Regions: Worldwide (50 million cases/year).
    • Vectors: Aedes aegypti, Aedes albopictus.
    • Transmission: Human-to-human (no animal reservoir).
    • Types: Dengue fever, dengue hemorrhagic fever (severe).
    • Control: Larval habitat reduction, genetic control (sterile male releases).

    West Nile Virus

    • Regions: Africa, Middle East, Europe, Americas.
    • Vectors: Culex pipiens, Culex quinquefasciatus, Culex tarsalis.
    • Hosts: Birds (primary reservoir), human & horses (dead-end hosts).
    • Control: Mosquito reduction.

    Japanese Encephalitis

    • Regions: Asia, Papua New Guinea.
    • Vectors: Culex tritaeniorhynchus, Culex vishnui (breed in rice fields).
    • Hosts: Birds (primary), pigs (amplifying), humans (dead-end).
    • Control: Vaccination, vector control.

    Chikungunya

    • Regions: Africa, Asia, Indian Ocean, Europe.
    • Vectors: Aedes aegypti, Aedes albopictus.
    • Hosts: Monkeys in Africa (possible zoonotic transmission).
    • Control: Mosquito habitat reduction.

    Filariasis

    • Vectors: Culex, Aedes, Mansonia, mosquitoes.
    • Forms:
      • Bancroftian filariasis (W. bancrofti): No animal reservoir.
      • Brugian filariasis (B. malayi): Reservoirs include monkeys, cats.
    • Periodic Forms: Nocturnally periodic (Culex quinquefasciatus, Anopheles), Diurnally subperiodic (Aedes polynesiensis).
    • Control: Mass drug administration (MDA), bed nets, vector control.

    Control Strategies for Culicine Mosquitoes

    • Aedes Control: Source reduction (eliminate breeding sites), larvicides (temphos, methoprene, Bacillus thuringiensis israelensis (Bti)), genetic control (sterile male release), vaccination (yellow fever).
    • Culex Control: Sanitation improvements, insecticides (temephos, methoprene, chlorpyrifos), expanded polystyrene beads in pit latrines.
    • Mansonia Control: Weed removal/herbicides to eliminate aquatic plants, granular insecticides for larval control.
    • Filariasis Control: Mass drug administration (albendazole + ivermectin), insecticide-treated bed nets (ITNs), WHO's global program to eliminate lymphatic filariasis.

    Black Flies (Simuliidae)

    • Family: Simuliidae
    • Found worldwide with >200 species in 25 genera.
    • Medically important genus: Simulium
    • Other genera: Prosimulium, Austrosimulium

    Main Disease: Onchocerciasis (River Blindness)

    • Vector:
      • Africa: Simulium damnosum complex, Simulium neavei
      • Central & South America: Simulium ochraceum, Simulium metallicum, Simulium exiguum
    • Other transmissions: Simulium amazonicum (Mansonella ozzardi - filarial parasite, usually non-pathogenic).

    General Characteristics

    • Small (1.5–4 mm).
    • Usually black, but some species have other colors/patterns.
    • Humped thorax.

    Head Features

    • Females: Dichoptic eyes.
    • Males: Holoptic eyes (touching).
    • Males have larger upper eye lenses.
    • Short, 11-segmented antennae.
    • Short, inconspicuous mouthparts with hanging maxillary palps.

    Biting Mechanism

    • Labrum stretches skin.
    • Mandibles and maxillae scrape and rupture blood capillaries.
    • Blood is sucked up.

    Wing Features

    • Short, broad wings with few veins.
    • No scales or prominent hairs.
    • Colorless or nearly so.
    • Wings rest over body like closed scissors.

    Legs and Abdomen

    • Legs with fine hairs, possible bands.
    • Tarsi with simple claws.
    • Short, squat abdomen with fine hairs.

    Life Cycle of Black Flies

    • Eggs: Triangular, black or brown, laid in flowing water.
    • (Simulium ochraceum): Eggs scattered across water.
    • Larvae: Cylindrical, swollen abdomen, attach to surfaces in flowing water.
    • Pupae: Attached to underwater surfaces in cocoons.
    • Adults: Emerge from pupae, fly long distances, lifespan several weeks.

    Onchocerciasis Transmission

    • Infected black fly bites human --> injects L3 filarial larvae.
    • Larvae mature, form skin nodules.
    • Adult worms produce microfilariae migrating through skin.
    • Black fly bites infected person, ingests microfilariae.
    • Microfilariae mature into infective L3 larvae inside fly, cycle repeats.

    Onchocerciasis Symptoms

    • Severe itching, skin thickening.
    • Depigmentation.
    • Eye infection and blindness.

    Onchocerciasis Prevention

    • Vector control (reducing black fly populations).
    • Mass drug administration (MDA) with Ivermectin.

    Control of Black Flies

    • Personal Protection: Insect repellents, protective clothing, avoiding infested areas during peak biting times.
    • Community-Level Control: Reducing breeding sites (removing vegetation, modifying water flow), larvicides (Bti), and MDA with Ivermectin.

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    Description

    Explore the fascinating world of Culicinae mosquitoes, including significant genera like Culex and Aedes. Learn about their breeding habits, disease transmission capabilities, and specific characteristics that differentiate them. This quiz will enhance your understanding of these important vectors in public health.

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