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PubMed This is a summary of 14 peer-reviewed journal articles Updated
Infectious Disease

What Insects Transmit Filariasis Parasites? Explained

At a Glance

Filariasis parasites are transmitted by specific insect bites depending on the disease. Mosquitoes spread lymphatic filariasis, blackflies transmit river blindness, deerflies carry the African eye worm, and midges spread mansonelliasis. The infection cannot spread locally in non-endemic areas.

Learning you have a parasitic infection from a past insect bite can be shocking and deeply overwhelming. The specific insect that transmits filariasis depends entirely on the type of parasite involved. In all cases, the disease is spread when an infected insect bites a human, depositing microscopic worm larvae that enter the body through the bite wound [1]. If you are trying to understand your past exposure, knowing which bugs carry which parasites is a key piece of the puzzle.

Here is a breakdown of the specific insects responsible for transmitting the different types of filariasis:

Lymphatic Filariasis

Lymphatic filariasis (which often leads to lymphedema, or severe, chronic tissue swelling) is caused primarily by the parasites Wuchereria bancrofti, Brugia malayi, and Brugia timori [2][3].

  • Vector: Mosquitoes.
  • Specifics: Various mosquito genera can transmit these parasites [4]. For example, Culex quinquefasciatus is a major mosquito vector in many parts of the world, including India [4][5].

Onchocerciasis (River Blindness)

Onchocerciasis is caused by the Onchocerca volvulus parasite [6].

  • Vector: Blackflies.
  • Specifics: This disease is transmitted by bites from blackflies belonging to the genus Simulium [6]. In Sub-Saharan Africa, the primary carrier is the Simulium damnosum species complex [7][8]. These flies typically breed in fast-flowing rivers and streams [7][9].

Loiasis (African Eye Worm)

Loiasis is caused by the Loa loa parasite [10].

  • Vector: Deerflies.
  • Specifics: The infection is transmitted by deerflies of the genus Chrysops [10][11]. These flies are primarily found in the rainforests and swamp forests of West and Central Africa [10][11][12].

Mansonelliasis

Mansonelliasis is caused by three different Mansonella parasites, each with slightly different carriers.

  • Vector: Biting midges and blackflies.
  • Specifics:
    • Mansonella perstans (found in sub-Saharan Africa and parts of Central and South America) is transmitted by biting midges of the genus Culicoides [13][14].
    • Mansonella streptocerca (found in West and Central African rainforests) is also transmitted by Culicoides midges [14].
    • Mansonella ozzardi (found in Latin America and the Caribbean) can be transmitted by both Culicoides midges and Simulium blackflies, depending on the specific geographic region [14].

Can I Spread This to Others?

A very common and understandable fear is that a local insect might bite you and spread the infection to your family or neighbors. Fortunately, the transmission of these parasites is a highly complex process [1]. It requires specific, competent insect vectors and precise environmental conditions—such as exact temperature and humidity levels—to allow the parasite to develop inside the insect [1][5]. Because of these strict requirements, if you are currently living in a non-endemic area (like the United States or Europe), you will not spread the disease to others through local bug bites [5][1].

Knowing the region you visited, the types of insects you were exposed to, and the environments you spent time in (such as near fast-flowing rivers or in swamp forests) can help your healthcare team determine which specific filariasis parasite might be causing your symptoms. Identifying the exact parasite is a crucial first step, because the treatments for different types of filariasis vary significantly and require tailored medical approaches.

Common questions in this guide

Can mosquitoes transmit filariasis?
Yes, mosquitoes are the primary vectors for lymphatic filariasis. Various species, including those in the Culex genus, can transmit the microscopic worm larvae that cause this specific type of parasitic infection.
What bug causes river blindness (onchocerciasis)?
River blindness is transmitted by bites from infected blackflies. These flies belong to the Simulium genus and typically breed in fast-flowing rivers and streams, most commonly in Sub-Saharan Africa.
How do you get the African eye worm (Loa loa)?
The Loa loa parasite is transmitted to humans through the bites of infected deerflies. These flies are primarily found in the rainforests and swamp forests of West and Central Africa.
Can I spread filariasis to my family through local bug bites?
If you live in a non-endemic area like the United States or Europe, you will not spread the infection to others. The parasites require very specific insect species and precise environmental conditions to develop and spread.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Based on my travel history and symptoms, which specific filariasis parasite do you suspect I have?
  2. 2.Do we need to perform specific blood tests or skin snips to confirm the exact species of the parasite?
  3. 3.Are there any specific specialists, such as an infectious disease doctor or a tropical medicine expert, that I should be referred to for my diagnosis and treatment?
  4. 4.Given the exact parasite we are treating, what specific side effects should I watch for when starting medication?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

Related questions

Asymptomatic Mansonelliasis: Treatment Options ExplainedHow to Treat Filariasis Testicular Swelling (Hydrocele)Is Filariasis Contagious? How It SpreadsIs Lymphatic Filariasis Swelling Completely Reversible?Why Screen for Loa Loa Before Filariasis Treatment?Loa Loa Worm in Eye: Symptoms and TreatmentADLA Symptoms & Acute Attacks in Lymphatic FilariasisWhat Are Mazzotti Reaction Symptoms After Treatment?Skin Snip Biopsy for River Blindness: What to ExpectWhat Are Calabar Swellings? Symptoms & Causes of LoiasisWhat is the Filarial Dance Sign on Ultrasound?Why Is My Filariasis Blood Test Done at Night?Why Use Doxycycline for Filariasis?

References

References (14)
  1. 1

    Surveillance of Wuchereria bancrofti infection by anti-filarial IgG4 in urine among schoolchildren and molecular xenomonitoring in Sri Lanka: a post mass drug administration study.

    Takagi H, Yahathugoda TC, Tojo B, et al.

    Tropical medicine and health 2019; (47()):39 doi:10.1186/s41182-019-0166-5.

    PMID: 31223271
  2. 2

    Detection and quantification of Wuchereria bancrofti and Brugia malayi DNA in blood samples and mosquitoes using duplex droplet digital polymerase chain reaction.

    Jongthawin J, Intapan PM, Lulitanond V, et al.

    Parasitology research 2016; (115(8)):2967-72 doi:10.1007/s00436-016-5051-0.

    PMID: 27085707
  3. 3

    Comparison of the Impact of Annual and Semiannual Mass Drug Administration on Lymphatic Filariasis Prevalence in Flores Island, Indonesia.

    Supali T, Djuardi Y, Lomiga A, et al.

    The American journal of tropical medicine and hygiene 2019; (100(2)):336-343 doi:10.4269/ajtmh.18-0570.

    PMID: 30560772
  4. 4

    Vector incrimination studies of lymphatic filariasis in rural areas of endemic Datia district of Madhya Pradesh, India.

    Anjal K, Rawal V, Pandey S, et al.

    Transactions of the Royal Society of Tropical Medicine and Hygiene 2025; (119(9)):1059-1065 doi:10.1093/trstmh/traf045.

    PMID: 40298333
  5. 5

    Population genomics of the filarial nematode parasite Wuchereria bancrofti from mosquitoes.

    Small ST, Reimer LJ, Tisch DJ, et al.

    Molecular ecology 2016; (25(7)):1465-77 doi:10.1111/mec.13574.

    PMID: 26850696
  6. 6

    Progress report on the elimination of human onchocerciasis, 2015-2016.

    Releve epidemiologique hebdomadaire 2016; (91(43)):505-14.

    PMID: 27801998
  7. 7

    Ecological characteristics of Simulium breeding sites in West Africa.

    Cheke RA, Young S, Garms R

    Acta tropica 2017; (167()):148-156 doi:10.1016/j.actatropica.2016.12.022.

    PMID: 28040485
  8. 8

    Mvolo County, an Onchocerciasis Endemic Area in Western Equatoria State, South Sudan: An Entomological Study to Prepare for a "Slash and Clear" Community-Based Vector Control Intervention.

    Lakwo TL, Alinda P, Jada SR, et al.

    Research and reports in tropical medicine 2024; (15()):59-71 doi:10.2147/RRTM.S464874.

    PMID: 38895129
  9. 9

    Onchocerca volvulus transmission in the Mbam valley of Cameroon following 16 years of annual community-directed treatment with ivermectin, and the description of a new cytotype of Simulium squamosum.

    Hendy A, Krit M, Pfarr K, et al.

    Parasites & vectors 2021; (14(1)):563 doi:10.1186/s13071-021-05072-y.

    PMID: 34727965
  10. 10

    Atypical Clinical Manifestations of Loiasis and Their Relevance for Endemic Populations.

    Buell KG, Whittaker C, Chesnais CB, et al.

    Open forum infectious diseases 2019; (6(11)):ofz417 doi:10.1093/ofid/ofz417.

    PMID: 31696139
  11. 11

    Loa loa filariasis in a tropical savanna area: report of one case in Ouagadougou.

    Ouédraogo NA, Korsaga-Somé N, Traoré F, et al.

    International journal of dermatology 2020; (59(4)):482-483 doi:10.1111/ijd.14782.

    PMID: 31975376
  12. 12

    Chronic kidney disease related to Loa loa microfilaremia in a rural area of the Republic of Congo: a population-based cross-sectional study.

    Boullé C, Campillo JT, Hemilembolo MC, et al.

    Infectious diseases of poverty 2025; (14(1)):88 doi:10.1186/s40249-025-01356-y.

    PMID: 40841693
  13. 13

    Limitations of PCR detection of filarial DNA in human stools from subjects non-infected with soil-transmitted helminths.

    Doret MPM, Nana-Djeunga HC, Nzune-Toche N, et al.

    Parasite (Paris, France) 2021; (28()):47 doi:10.1051/parasite/2021046.

    PMID: 34047694
  14. 14

    Human Filariasis in Travelers and Migrants: A Retrospective 25-year Analysis at the Institute of Tropical Medicine, Antwerp, Belgium.

    Bottieau E, Huits R, Van Den Broucke S, et al.

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    PMID: 34463732

This page provides educational information about the insects that transmit filariasis parasites. Always consult an infectious disease or tropical medicine specialist for an accurate diagnosis and appropriate medical care.

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