Cordylobia rodhaini

Cordylobia rodhaini also known as the Lund's fly derived its common name from captain Lund, who was the first European to show symptoms of the disease caused by the larvae of the same fly.[2] The Lund’s fly belongs to the genus Cordylobia, a group of flies from the family Calliphoridae.[3][4] The larvae of the Lund’s fly are parasites of thinned-skinned mammals, especially the Gambian rat, mona monkey and small antelopes [5] and are only accidental parasites of humans.[2][6][7] The adult flies feeds on rotting fruits, vegetables and animal feces, and are most abundant in the wet season.[6] Like many tropical insects they are most active in the dark periods and have the greatest activity early in the morning and late in the evening while resting typically between 8am to 5pm.[8] The Lund’s fly are largely confined to tropical Africa, especially the rainforest areas in Sub-Saharan Africa.[7] However, as a result of human migration, the parasitic infections they cause have been recorded in other continents including Europe and Asia.[9]

Cordylobia rodhaini
Scientific classification
Kingdom:
Animalia
Phylum:
Arthropoda
Class:
Insecta
Order:
Diptera
Family:
Calliphoridae
Subfamily:
Bengaliinae
Genus:
Cordylobia
Species:
C. rodhaini
Binomial name
Cordylobia rodhaini
Gedoelst, 1910
Synonyms

Cordylobia ebadiana Lehrer & Goergen, 2006[1]

Life Cycle

The life cycle of the Lund's fly typically lasts from 55 to 67 days.[10] The female fly lays up to 500 eggs and deposits her eggs on dry sand polluted with the excrement of animals, or can also lay them on human clothing.[2] In about three days, the larva attached to its host, is then activated by the warm body of the host. The Lund’s fly larvae then hatches and breaks through the skin. A maturing larva induces a painful swelling. In approximately 12 to 15 days, the larva reaches a length of about 23 mm, exits the skin of the host, and falls to the ground to pupate. The adult fly emerges in 23 to 26 days, and the life cycle continues.

Larvae structure

The Lund’s fly is parasitic at its larval stage. Under examination with a scanning electron microscope, it appears whitish and barrel-shaped, with 11 segments.[11] Its body is almost completely covered by large conic-shaped spines. These spines serve as a point of attachment to its host. The larvae have a brown apex, pointing towards the posterior end where there are fewer spines. There exist two bulges in the anterior end with paired mouth hooks at the anterior end of the larvae. After hatching, the larvae penetrates into the dermis and molts to second and third instar larvae before emerging from the skin.[6][7] The third instar larvae has an approximate length of 1.5 cm and is distinctively less elongated and conical in shape, compared to the second instar larvae [11]

Lund's fly-induced myiasis

Myiasis is generally defined as the infestation of animal tissue by the larvae of some flies. The larva of myiasis-causing flies feed on animal tissue and/or bodily fluids.[10][12] Myiasis caused by the Lund’s fly larvae have presently been reported in Ethiopia, Uganda, Congo, Kenya, Ghana and Cameroon.[2][4][8] It is very similar to the myiasis that caused by the Tumbu fly, the latter co-existing in the same geographical regions as the Lund's fly.[3][12][13] Clinical symptoms start with the formation of a red papule, which is characterized by a small raised swollen area of the skin. These can form on any area of the skin, with the arms, legs, arms and back most frequently affected.[2] Patients typically do not report pain at this stage of infection.[4] The papule enlarges with time, penetrates deep into the skin and develops a central opening, now classified as a furuncle. The central opening facilitates gaseous exchange for the larvae while a serous fluid also exits the same opening.[2] The central opening also makes it possible for the larvae to excrete its fecal matter.[8] At this point, itching and burning sensation are usually described by patients in the affected areas of the skin. Patients also report symptoms such as insomnia (due to pains at night) and fatigue. The disease is usually self-limiting as the larvae drops out, upon reaching the third instar larval stage. Also there have not been any reports of Lund’s fly larvae infestation in systemic areas, such as the internal organs, or blood vessels.[5][10] The most serious incident of Lund's fly induced myiasis reported so far resulted in swelling of the lymph nodes due to adverse immune reactions in the patient.[5] A major distinction between myiasis caused by Lund’s fly and myiasis caused by other flies is that lesions in Lund’s fly myiasis are usually smaller and multiple.[10] Myiasis caused by Tumbu fly is, on the other hand, similar to that caused by Lund's fly; the two flies belong to the same genus and share similar characteristics.[8]

Treatment

As the larvae fall off eventually, the disease is self-limiting and no treatment is usually needed.[2][6] However, to facilitate healing, the larvae can be physically removed from the infected region. This is done by applying gentle manual pressure to any two ends of the lesion until the larvae comes out [2][5] Occasionally, petroleum jelly or oil is applied to the opening in the lesion, in order to prevent oxygen supply to the larvae, thereby forcing the larvae to move closer to the surface.[10] Improper removal of the larvae could lead to inflammation of the lymph nodes as bursting of the fluid from the larvae could lead to allergic reactions in some people.[5] Proper covering of the wound will prevent further infection.[12] Unsterilized objects should not be used to open lesions as this could result in infection. Hyperpigmentation may persist on the skin of the infected area months after infection.[5] Also lack of experience in diagnosing Lund's fly induced myiasis could lead to a misdiagnosis of impetigo, insect bites, folliculitis or other skin disorders.[10]

Prevention and control

Generally, humans are accidental hosts of myiasis as a result of Lund’s fly larvae infestation and are therefore less likely to be infected. However, infestation can pose a health problem for the local population in the endemic region and tourists alike.[8] Infestations of Lund’s fly larvae are usually diagnosed in tourists and foreign workers that previously travelled to the endemic regions.[7][8][9] Therefore, incidence rates might be under-reported in endemic regions and might be treated by local means. Even as it can be spread by human travel, it has not reported to be contagious and is also less likely to thrive in regions other than Sub-Saharan Africa, due to differences in climate.[2] As eggs are usually laid on wet clothing in endemic regions, clothes should not be left outside for long periods, specifically at dawn or twilight, as this is when Lund’s flies are most active and likely to lay eggs. Also, ironing all clothes to kill eggs or larvae will help to reduce the incidence of myiasis.[12] Good hygiene can also play a role in preventing myiasis, as the Lund’s fly is known to feed in dirty surroundings and lay eggs where they breed.

References
  1. Rognes, K. (2011). A review of the monophyly and composition of the Bengaliinae with the description of a new genus and species, and new evidence for the presence of Melanomyinae in the Afrotropical Region (Diptera, Calliphoridae). Zootaxa, 2964(1), 1–60. doi:http://dx.doi.org/10.11646/zootaxa.2964.1.1
  2. Veraldi, Stefano; Serini, Stefano Maria; Suss, Luciano (2014). "Three cases of cutaneous myiasis caused by Cordylobia rodhaini" (PDF). The Journal of Infection in Developing Countries. 8 (02): 249–251. doi:10.3855/jidc.3825. ISSN 1972-2680.
  3. Ockenhouse CF, Samlaska CP, Benson PM, Roberts LW, Eliasson A, Malane S, Menich MD (1990). "Cutaneous myiasis caused by the African tumbu fly (Cordylobia anthropophaga)". Archives of Dermatology. 126 (2): 199–202. doi:10.1001/archderm.1990.01670260069013. PMID 2301958.
  4. Vanhecke, C.; Nguimfack, R.N.K.; Lemarchand, J.; Reichart, V. & Le Gall, P. (2015). "Facial edema caused by multifocal myiasis of Cordylobia rodhaini in Yaounde - Cameroon". Presse Médicale. 44: 564–566.
  5. Pampiglione, S.; Schiavon, S. & Fioravanti, M. (1992). "Extensive furuncular myiasis due to Cordylobia rodhaini larvae". British Journal of Dermatology. 126: 418–419. doi:10.1111/j.1365-2133.1992.tb00698.x.
  6. Geary, M.; Hudson, B.; Russell, R. & Hardy, A. (1999). "Exotic myiasis with Lund's fly (Cordylobia rodhaini)". Medical Journal of Australia. 171: 654–655.
  7. Kremer, M.; Lenys, J. & Basset, M. (1970). "Two cases of Cordylobia rodhaini myiasis contracted in Cameroon and diagnosed in Alsace". Bulletin de la Société de Pathologie Exotique et de ses Filiales. 63: 592–596.
  8. Pezzi, M.; Cultrera, R.; Chicca, M.; Leis, M. (2015). "Furuncular Myiasis Caused by Cordylobia rodhaini (Diptera: Calliphoridae): A Case Report and a Literature Review". Journal of Medical Entomology. 52 (2): 151–155. doi:10.1093/jme/tju027. ISSN 0022-2585.
  9. Scholten, T.H. & Hicks, R.J. (1973). "Myiasis by Cordylobia rodhiani contracted in Africa and diagnosed in Canada". Canadian Journal of Public Health. 64: 488–489.
  10. Tamir, J.; Haik, J. & Schwartz, E. (2003). "Myiasis with Lund's Fly (Cordylobia rodhaini) in travelers". Journal of Travel Medicine. 10: 293–295. doi:10.2310/7060.2003.2732. PMID 14531984.
  11. Pezzi, M.; Cultrera, R.; Chicca, M. & Leis, M. (2015). "Scanning Electron Microscopy Investigations of Third-Instar Larva of Cordylobia rodhaini (Diptera: Calliphoridae), an agent of furuncular myiasis". Journal of Medical Entomology. 52: 368–374. doi:10.1093/jme/tjv022.
  12. Caissie, R.; Beaulieu, F.; Giroux, M.; Berthod, F. & Landry, P. (2008). "Cutaneous myiasis: Diagnosis, treatment, and prevention. Journal of Oral and Maxillofacial Surgery". Journal of Medical Entomology. 66: 560–568. doi:10.1016/j.joms.2007.09.005.
  13. Veraldi, S.; Brusasco, A. & Suss, L. (1993). "Cutaneous myiasis caused by larvae of Cordylobia anthropophaga (Blanchard)". International Journal of Dermatology. 32: 184–187. doi:10.1111/j.1365-4362.1993.tb02789.x.
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