Filariasis

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Filariasis
Other names: Filarial infection[1]
Life cycle of Wuchereria bancrofti, a parasite that causes filariasis
SpecialtyInfectious disease
SymptomsHeadache, fever, chills[2]
ComplicationsTropical pulmonary eosinophilia, filarial arthritis, filarial breast abscesses[2]
CausesWuchereria bancrofti, Brugia malayi, Brugia timori[2]
Diagnostic methodPeripheral smear, PCR[2]
Differential diagnosisLymphoma, testicular neoplasms, congenital abnormalities of lymphatics, pelvic malignancy[2]
TreatmentDEC, surgery[2]
Frequency120 million people worldwide[3]

Filariasis is a parasitic disease caused by an infection with roundworms of the Filarioidea type.[4] These are spread by blood-feeding insects such as black flies and mosquitoes. They belong to the group of diseases called helminthiases. These parasites exist in the wild in subtropical parts of southern Asia, Africa, the South Pacific, and parts of South America. One does not acquire them in the Northern Hemisphere like Europe or the US.[5][2]

Eight known filarial worms have humans as a definitive host[6][7], and are divided into three groups according to the part of the body they affect:

The adult worms, which usually stay in one tissue, release early larval forms known as microfilariae into the person's blood. These circulating microfilariae can be taken up during a blood meal by an insect vector; in the vector, they develop into infective larvae that can be spread to another person.Individuals infected by filarial worms may be described as either "microfilaraemic" or "amicrofilaraemic", depending on whether microfilariae can be found in their peripheral blood. Filariasis is diagnosed in microfilaraemic cases primarily through direct observation of microfilariae in the peripheral blood. Occult filariasis is diagnosed in amicrofilaraemic cases based on clinical observations and, in some cases, by finding a circulating antigen in the blood.[2][17]

Signs and symptoms

Image- left leg affected by filariasis

The most spectacular symptom of lymphatic filariasis is elephantiasis – edema with thickening of the skin and underlying tissues—which was the first disease discovered to be transmitted by mosquito bites.Elephantiasis results when the parasites lodge in the lymphatic system.Elephantiasis affects mainly the lower extremities, while the ears, mucous membranes, and amputation stumps are affected less frequently. However, different species of filarial worms tend to affect different parts of the body; Wuchereria bancrofti can affect the legs, arms, vulva, breasts, and scrotum , while Brugia timori rarely affects the genitals. Those who develop the chronic stages of elephantiasis are usually free from microfilariae, and often have adverse immunological reactions to the microfilariae, as well as the adult worms.[18][19][2][18]

The subcutaneous worms present with rashes, urticarial papules, and pigmentation macules. Onchocerca volvulus manifests itself in the eyes, causing "river blindness", one of the leading causes of blindness in the world. Serous cavity filariasis presents with symptoms similar to subcutaneous filariasis, in addition to abdominal pain, because these worms are also deep-tissue dwellers.[20][21]

Cause

Culex pipiens

In terms of the etiology we find that some of the causes of Filariasis are due to Wuchereria bancrofti, Brugia malayi, and Brugia timori. Its transmission is done via five genera of mosquitoes.[2]

Mechanism

Human filarial nematode worms have complicated life cycles, which primarily consists of five stages. After the male and female worms mate, the female gives birth to live microfilariae by the thousands. The microfilariae are taken up by the vector insect during a blood meal. In the intermediate host, the microfilariae molt and develop into third-stage larvae. Upon taking another blood meal, the vector insect, injects the infectious larvae into the dermis layer of the skin. After about one year, the larvae molt through two more stages, maturing into the adult worms.[2][22]

Diagnosis

Peripheral blood smear(stained and unstained)

Filariasis is usually diagnosed by identifying microfilariae on Giemsa stained, thin and thick blood film smears, using the "gold standard" known as the finger prick test. The finger prick test draws blood from the capillaries of the finger tip; larger veins can be used for blood extraction, but strict windows of the time of day must be observed. Blood must be drawn at appropriate times, which reflect the feeding activities of the vector insects. Examples are W. bancrofti, whose vector is a mosquito; night is the preferred time for blood collection. Loa loa's vector is the deer fly; daytime collection is preferred. This method of diagnosis is only relevant to microfilariae that use the blood as transport from the lungs to the skin. Some filarial worms, such as M. streptocerca and O. volvulus, produce microfilariae that do not use the blood; they reside in the skin only. For these worms, diagnosis relies upon skin snips and can be carried out at any time.[23][12][2][24]

Concentration methods

Various concentration methods are applied: membrane filter, and Knott's concentration method.[2][24]

Polymerase chain reaction (PCR) and antigenic assays, which detect circulating filarial antigens, are also available for making the diagnosis. The latter are particularly useful in amicrofilaraemic cases. Spot tests for antigen[25] are far more sensitive, and allow the test to be done anytime, rather in the late hours.

Medical imaging, such as CT or MRI, may reveal "filarial dance sign" in the chylous fluid; X-ray tests can show calcified adult worms in lymphatics. The DEC provocation test is performed to obtain satisfying numbers of parasites in daytime samples.[2][26]

Treatment

The recommended treatment for people outside the United States is albendazole combined with ivermectin.[27][28] A combination of diethylcarbamazine and albendazole is also effective.[27][29] Side effects of the drugs include nausea, vomiting, and headaches. All of these treatments are microfilaricides; they have no effect on the adult worms. While the drugs are critical for treatment of the individual, proper hygiene is also required.There is good evidence that albendazole alone; or addition of albendazole to diethylcarbamazine or ivermectin, makes minimal difference in clearing microfilaria or adult worms from blood circulation.[30][31] [32][33]

Diethylcarbamazine-medicated salt is effective in controlling lymphatic filariasis while maintaining its coverage at 90% in the community for six months.[34]

Different trials were made to use the known drug at its maximum capacity in absence of new drugs. In a study from India, it was shown that a formulation of albendazole had better anti-filarial efficacy than albendazole itself.[35]

In 2003, the common antibiotic doxycycline was suggested for treating elephantiasis.[36] Filarial parasites have symbiotic bacteria in the genus Wolbachia, which live inside the worm and seem to play a major role in both its reproduction and the development of the disease. This drug has shown signs of inhibiting the reproduction of the bacteria, further inducing sterility.[29] Clinical trials in June 2005 by the Liverpool School of Tropical Medicine reported an eight-week course almost completely eliminated microfilaraemia.[37]

  • Albendazole

    Albendazole

  • Ivernectin

    Ivernectin

History

Patrick Manson MD
Satoshi Ōmura 大村 智, PhD.

Sir Patrick Manson was the first to discover that filariasis, a disease caused by parasitic worms, is transmitted by mosquitoes. His research in the late 19th century laid the foundation for modern tropical medicine[38]

In 2015 William C. Campbell and Satoshi Ōmura were co-awarded half of that year's Nobel prize in Physiology or Medicine for the discovery of the drug avermectin, which, in the further developed form ivermectin, has decreased the occurrence of lymphatic filariasis.[39]

A 2017 article by Ndeffo-Mbah, et al indicates Filarial diseases in humans offer prospects for elimination by means of vermicidal treatment. If the human link in the chain of infection can be broken, then notionally the disease could be wiped out in a season. There are complications in that multiple species overlap in certain regions and double infections are common. This creates difficulties for routine mass treatment because people with onchocerciasis in particular react badly to treatment for lymphatic filariasis.[40]

Other animals

Filariasis can also affect domesticated animals, such as cattle, sheep, and dogs.[41][42]

Cattle

Heartworm(Dirofilaria immitis)
  • Stenofilaria assamensis and others cause different diseases in Asia, in cattle and zebu.[46]

Horses

Dogs

See also

References

  1. ↑ Bhalla, Devender; Dumas, Michel; Preux, Pierre-Marie (2013). "Neurological manifestations of filarial infections". Handbook of Clinical Neurology. 114: 235–242. doi:10.1016/B978-0-444-53490-3.00018-2. ISSN 0072-9752. Archived from the original on 6 May 2024. Retrieved 16 August 2024.
  2. ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 Newman, Thomas E.; Juergens, Andrew L. (2024). "Filariasis". StatPearls. StatPearls Publishing. Archived from the original on 2 May 2023. Retrieved 4 August 2024.
  3. ↑ Morris-Jones, Rachael (2019). "18. Tropical dermatology". In Morris-Jones, Rachael (ed.). ABC of Dermatology (7th ed.). Hoboken: Wiley Blackwell. pp. 153–154. ISBN 978-1-119-48899-6. Archived from the original on 16 May 2022. Retrieved 17 May 2022.
  4. ↑ Center for Disease Control and Prevention. "Lymphatic Filariasis". Archived from the original on 27 May 2010. Retrieved 18 July 2010.
  5. ↑ "CDC — Lymphatic Filariasis FAQ". Archived from the original on 15 February 2015. Retrieved 13 March 2022.
  6. ↑ "Lymphatic filariasis". www.who.int. Archived from the original on 17 October 2019. Retrieved 11 August 2024.
  7. ↑ "About Lymphatic Filariasis". Filarial Worms. 5 June 2024. Retrieved 11 August 2024.
  8. ↑ "Lymphatic filariasis | About the Disease | GARD". rarediseases.info.nih.gov. Archived from the original on 15 June 2024. Retrieved 6 August 2024.
  9. ↑ Medeiros, Zulma M.; Vieira, Amanda V. B.; Xavier, Amanda T.; Bezerra, Gilberto S. N.; Lopes, Maria de Fátima C.; Bonfim, Cristine V.; Aguiar-Santos, Ana M. (January 2022). "Lymphatic Filariasis: A Systematic Review on Morbidity and Its Repercussions in Countries in the Americas". International Journal of Environmental Research and Public Health. 19 (1). doi:10.3390/ijerph19010316. Archived from the original on 12 August 2024. Retrieved 9 August 2024.
  10. ↑ Akue, Jean Paul; Eyang-Assengone, Elsa-Rush; Dieki, Roland (3 April 2018). "Loa loa infection detection using biomarkers: current perspectives". Research and Reports in Tropical Medicine. 9: 43–48. doi:10.2147/RRTM.S132380. ISSN 1179-7282. Archived from the original on 17 June 2024. Retrieved 6 August 2024.
  11. ↑ Bamuhiiga, Jotham T. (1998). "Mansonella Streptocerca: Another Filarial Worm in the Skin in Western Uganda". Community Eye Health Journal. 11 (26): 28. PMC 1706049. PMID 17492030.
  12. ↑ 12.0 12.1 Metzger, Wolfram Gottfried; Mordmüller, Benjamin (April 2014). "Loa loa—does it deserve to be neglected?". The Lancet Infectious Diseases. 14 (4): 353–357. doi:10.1016/S1473-3099(13)70263-9. Archived from the original on 20 August 2024. Retrieved 20 August 2024.
  13. ↑ "WHO | The 17 neglected tropical diseases". web.archive.org. 22 February 2014. Archived from the original on 22 February 2014. Retrieved 20 August 2024.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
  14. ↑ Wysmołek, Magdalena Elżbieta; Długosz, Ewa; Wiśniewski, Marcin (January 2022). "The Immunological Role of Vascular and Lymphatic Endothelial Cells in Filarial Infections". Animals. 12 (4): 426. doi:10.3390/ani12040426. ISSN 2076-2615. Archived from the original on 11 July 2024. Retrieved 14 August 2024.
  15. ↑ Simonsen, Paul E.; Onapa, Ambrose W.; Asio, Santa Maria (1 September 2011). "Mansonella perstans filariasis in Africa". Acta Tropica. 120: S109–S120. doi:10.1016/j.actatropica.2010.01.014. ISSN 0001-706X.
  16. ↑ Lima, Nathália F.; Veggiani Aybar, Cecilia A.; Dantur Juri, María J.; Ferreira, Marcelo U. (May 2016). "Mansonella ozzardi: a neglected New World filarial nematode". Pathogens and Global Health. 110 (3): 97–107. doi:10.1080/20477724.2016.1190544. ISSN 2047-7724. Archived from the original on 20 August 2024. Retrieved 19 August 2024.
  17. ↑ Cross, John H. (1996). "Filarial Nematodes". Medical Microbiology (4th ed.). University of Texas Medical Branch at Galveston. ISBN 978-0-9631172-1-2. Archived from the original on 3 January 2024. Retrieved 23 August 2024.
  18. ↑ 18.0 18.1 "Lymphatic filariasis". Health Topics A to Z. Source: The World Health Organization. Archived from the original on 18 September 2011. Retrieved 24 March 2013.
  19. ↑ "Elephantiasis". www.healthdirect.gov.au. 15 July 2024. Archived from the original on 12 August 2024. Retrieved 9 August 2024.
  20. ↑ "Onchocerciasis (river blindness)". www.who.int. Archived from the original on 11 April 2020. Retrieved 12 August 2024.
  21. ↑ Lustigman, Sara; Makepeace, Benjamin L.; Klei, Thomas R.; Babayan, Simon A.; Hotez, Peter; Abraham, David; Bottazzi, Maria Elena (January 2018). "Onchocerca volvulus: The Road from Basic Biology to a Vaccine". Trends in Parasitology. 34 (1): 64–79. doi:10.1016/j.pt.2017.08.011. ISSN 1471-5007. Archived from the original on 4 June 2024. Retrieved 22 August 2024.
  22. ↑ "Filariasis: Practice Essentials, Background, Pathophysiology". eMedicine. 2 February 2023. Archived from the original on 6 October 2017. Retrieved 22 August 2024.
  23. ↑ Mendoza, Natalia; Li, Alexa; Gill, Amber; Tyring, Stephen (November 2009). "Filariasis: diagnosis and treatment". Dermatologic Therapy. 22 (6): 475–490. doi:10.1111/j.1529-8019.2009.01271.x. Archived from the original on 2 November 2022. Retrieved 7 August 2024.
  24. ↑ 24.0 24.1 Mathison, Blaine A.; Couturier, Marc Roger; Pritt, Bobbi S. (24 September 2019). "Diagnostic Identification and Differentiation of Microfilariae". Journal of Clinical Microbiology. 57 (10): e00706–19. doi:10.1128/JCM.00706-19. ISSN 0095-1137. Archived from the original on 27 May 2024. Retrieved 23 August 2024.
  25. ↑ "Seva Fila" (PDF). JB Tropical Disease Research Centre & Department of Biochemistry, Mahatma Gandhi Institute of Medical Sciences. Archived (PDF) from the original on 4 March 2012. Retrieved 13 March 2022.
  26. ↑ Chandy, Anish; Thakur, Alok Singh; Singh, Mukesh Pratap; Manigauha, Ashish (1 July 2011). "A review of neglected tropical diseases: filariasis" (PDF). Asian Pacific Journal of Tropical Medicine. 4 (7): 581–586. doi:10.1016/S1995-7645(11)60150-8. ISSN 1995-7645. Archived (PDF) from the original on 20 August 2024. Retrieved 19 August 2024.
  27. ↑ 27.0 27.1 The Carter Center, Lymphatic Filariasis Elimination Program, archived from the original on 20 July 2008, retrieved 17 July 2008
  28. ↑ U.S. Centers for Disease Control, Lymphatic Filariasis Treatment, archived from the original on 4 May 2010, retrieved 17 July 2008
  29. ↑ 29.0 29.1 Taylor MJ, Hoerauf A, Bockarie M (October 2010). "Lymphatic filariasis and onchocerciasis". Lancet. 376 (9747): 1175–85. doi:10.1016/s0140-6736(10)60586-7. PMID 20739055. S2CID 29589578.
  30. ↑ Macfarlane CL, Budhathoki SS, Johnson S, Richardson M, Garner P (January 2019). "Albendazole alone or in combination with microfilaricidal drugs for lymphatic filariasis". The Cochrane Database of Systematic Reviews. 1 (1): CD003753. doi:10.1002/14651858.CD003753.pub4. PMC 6354574. PMID 30620051.
  31. ↑ Katiyar, D.; Singh, L. K. (2011). "Filariasis: Current status, treatment and recent advances in drug development". Current Medicinal Chemistry. 18 (14): 2174–2185. doi:10.2174/092986711795656234. ISSN 1875-533X. Archived from the original on 12 August 2024. Retrieved 7 August 2024.
  32. ↑ Turkington CA. "Filariasis". The Gale Encyclopedia of Public Health. 1: 351–353.
  33. ↑ Hewitt K, Whitworth JA (1 August 2005). "Filariasis". Medicine. 33 (8): 61–64. doi:10.1383/medc.2005.33.8.61.
  34. ↑ Adinarayanan S, Critchley J, Das PK, Gelband H, et al. (Cochrane Infectious Diseases Group) (January 2007). "Diethylcarbamazine (DEC)-medicated salt for community-based control of lymphatic filariasis". The Cochrane Database of Systematic Reviews (1): CD003758. doi:10.1002/14651858.CD003758.pub2. PMC 6532694. PMID 17253495.
  35. ↑ Gaur RL, Dixit S, Sahoo MK, Khanna M, Singh S, Murthy PK (April 2007). "Anti-filarial activity of novel formulations of albendazole against experimental brugian filariasis". Parasitology. 134 (Pt 4): 537–44. doi:10.1017/S0031182006001612. PMID 17078904. S2CID 24567214.
  36. ↑ Hoerauf A, Mand S, Fischer K, Kruppa T, Marfo-Debrekyei Y, Debrah AY, Pfarr KM, Adjei O, Buttner DW (2003), "Doxycycline as a novel strategy against bancroftian filariasis-depletion of Wolbachia endosymbionts from Wuchereria bancrofti and stop of microfilaria production", Med Microbiol Immunol (Berl), 192 (4): 211–6, doi:10.1007/s00430-002-0174-6, PMID 12684759, S2CID 23349595
  37. ↑ Taylor MJ, Makunde WH, McGarry HF, Turner JD, Mand S, Hoerauf A (2005), "Macrofilaricidal activity after doxycycline treatment of Wuchereria bancrofti: a double-blind, randomised placebo-controlled trial", Lancet, 365 (9477): 2116–21, doi:10.1016/S0140-6736(05)66591-9, PMID 15964448, S2CID 21382828
  38. ↑ Chernin, Eli (1983). "Sir Patrick Manson's Studies on the Transmission and Biology of Filariasis". Reviews of Infectious Diseases. 5 (1): 148–166. ISSN 0162-0886. Retrieved 20 April 2025.
  39. ↑ Andersson J, Forssberg H, Zierath JR (5 October 2015), "Avermectin and Artemisinin - Revolutionary Therapies against Parasitic Diseases" (PDF), The Nobel Assembly at Karolinska Institutet, archived (PDF) from the original on 5 October 2015, retrieved 5 October 2015
  40. ↑ Ndeffo-Mbah ML, Galvani AP (April 2017). "Global elimination of lymphatic filariasis". The Lancet. Infectious Diseases. 17 (4): 358–359. doi:10.1016/S1473-3099(16)30544-8. PMID 28012944.
  41. ↑ Megat Abd Rani, Puteri Azaziah; Irwin, Peter J.; Gatne, Mukulesh; Coleman, Glen T.; McInnes, Linda M.; Traub, Rebecca J. (8 April 2010). "A survey of canine filarial diseases of veterinary and public health significance in India". Parasites & Vectors. 3 (1): 30. doi:10.1186/1756-3305-3-30. ISSN 1756-3305. Archived from the original on 12 August 2024. Retrieved 11 August 2024.
  42. ↑ "Clinical and Laboratory Aspects of Filariasis" (PDF). NIH. Archived (PDF) from the original on 18 August 2024. Retrieved 17 August 2024.
  43. ↑ Johannes Kaufmann, Parasitic infections of domestic animals, Birkhäuser Verlag, Basel, ISBN 3-7643-5115-2, p. 106-107.
  44. ↑ "Onchocerciasis in Animals - Onchocerciasis in Animals". Merck Veterinary Manual. Archived from the original on 18 August 2024. Retrieved 15 August 2024.
  45. ↑ Trees, A. J.; Graham, S. P.; Renz, A.; Bianco, A. E.; Tanya, V. (May 2000). "Onchocerca ochengi infections in cattle as a model for human onchocerciasis: recent developments". Parasitology. 120 (7): 133–142. doi:10.1017/S0031182099005788. ISSN 1469-8161. Archived from the original on 18 August 2024. Retrieved 15 August 2024.
  46. ↑ "Stephanofilaria assamensis". 7 January 2022. doi:10.1079/cabicompendium.63216. Archived from the original on 25 November 2022. Retrieved 8 August 2024. {{cite journal}}: Cite journal requires |journal= (help)
  47. ↑ Pringle H (3 March 2011), The Emperor and the Parasite, archived from the original on 6 December 2019, retrieved 9 March 2011
  48. ↑ "About Dirofilariasis". Dirofilariasis. 10 May 2024. Archived from the original on 12 August 2024. Retrieved 8 August 2024.

Further reading

  • "Special issue", Indian Journal of Urology, 21 (1), January–June 2005, archived from the original on 10 July 2020, retrieved 13 March 2022
  • "Filariasis". Therapeutics in Dermatology. June 2012. Archived from the original on 24 April 2015. Retrieved 24 July 2012.

External links

Classification
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