American Journal of Public Health Research
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American Journal of Public Health Research. 2018, 6(2), 26-30
DOI: 10.12691/ajphr-6-2-1
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Entomological Evaluation by Dissection of Adult Simulium damnosum Complex for Larvae of Onchocerca volvulus, Following CDTI in Amagu Agba Community, Ishielu L.G.A-Ebonyi State, Nigeria

Nnadozie R.I.A.1, Onyenwe E.2, , Ibediugha B.N.2 and Okorie A.G.2

1Department of Biology, Federal University of Technology Owerri, Imo State, Nigeria

2Department of Zoology and Environmental Biology, Michael Okpara University of Agriculture, Umudike, Abia State Nigeria

Pub. Date: March 09, 2018

Cite this paper:
Nnadozie R.I.A., Onyenwe E., Ibediugha B.N. and Okorie A.G.. Entomological Evaluation by Dissection of Adult Simulium damnosum Complex for Larvae of Onchocerca volvulus, Following CDTI in Amagu Agba Community, Ishielu L.G.A-Ebonyi State, Nigeria. American Journal of Public Health Research. 2018; 6(2):26-30. doi: 10.12691/ajphr-6-2-1


The study was carried out to verify reports of persistent transmission of onchocerciasis, despite long-term Community Directed Treatment with Ivermectin, (CDTI). Blackflies were collected along Asu River using human baits. A total of 91 female Simulium damnosum complex adults were caught and dissected- using a dissecting microscope- for microfilariae of O. volvulus. 58 flies representing (63.70%) of the total number of captured flies were caught in the month of June while 33 (36.20%) were caught in July. Despite ivermectin treatment, evidence of O. volvulus transmission was documented in Amagu Agba. A total of 27 larvae were recovered from the three body segments of the dissected flies, of this number, 17 larvae were recovered from the head region and a total of 10 were recovered from the thorax and abdomen representing 62.96 % and 37.04 % respectively of the total number of larvae recovered. The proportion of infected flies recorded was 8 (8.8 %) while the proportion of infective flies recorded was 17 (18.7%) of the total number of infected and infective flies. The high proportion of infective flies is indicative of active transmission in and around the study area. This should not be so as CDTI is currently going on in the area. Some militating factors such as: patterns of treatment coverage and compliance, parasite ivermectin susceptibility, parasite immigration in flies or people, may be responsible for the current unsuccessful ivermectin treatment strategy.There is therefore need for consistent and effective ivermectin distribution pattern and its resultant onchocerciasis prevalence, detected with blackfly dissection techniques and or more reliably detected in both blackfly population and human subjects through a combination of some molecular-based detection techniques and biocontrol approaches. Adopting these measures together with community-ownership participation concept, will successfully interrupt transmission in Amagu Agba community and other endemic areas.

Amagu Agba CDTI Ivermectin Onchocerca volvulus Onchocerciasis Simulium damnosum complex

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[1]  Opara, K. N., Fagbemi, O. B., Ekwe, A. and Okenu, D. M. N. (2005). Status of forest onchocerciasis in the lower Cross River Basin, Nigeria: Entomological profile after five years of ivermectin intervention. American Journal of Tropical Medicine and Hygiene, 73(2): 371-376.
[2]  Etya’ale, M. E. (2001). Vision 2020: Update on Onchocerciasis. Community Eye Health, 14(38): 19-21.
[3]  World Health Organization (1997). Conquering suffering enriching humanity. World Health Organization Report, Geneva.
[4]  Atting, A. I., Ejezie, G. C., Braide, E. I., Opara, K. N. and Ekwe, A. (2005). Seasonal variations in human onchocerciasis transmission by blackflies (Simulium damnosum s.l.) in a forest area of Cross River State, Nigeria. African Journal of Applied Zoology and Environmental Biology, 7: 14-18.
[5]  Edungbola, L. D. (1991). Onchocerciasis control in Nigeria. Parasitology Today, 7(5): 97-99.
[6]  Nwoke, B.E.B. (1990). The socio-Economic Aspects of Human Onchocerciasis in Africa: Present Appraisal. Journal of hygiene, epidemiology, microbiology and immunology, 34(1): 37-44.
[7]  Opara, K. N., Usip, L. P. and Akpabio, E. E. (2008). Transmission dynamics of Simulium damnosum in rural communities of Akwa Ibom State, Nigeria. Journal of Vector Borne Diseases, 45: 225-230.
[8]  World Health Organization (1999). Twenty-five years of Onchocerciasis Control Programme (OCP) 1974-1999. World Health Organization, Geneva.
[9]  Hall, L & Pearlman E (1999) pathogenesis of onochocercae keratitis. Clin Microbial Rev 12:445-53
[10]  Forgione, M. (2006). Onchocerciasis. eMedicine, 23 May 2002. Available online at: 15/07/2016.
[11]  Cupp E. W., Sauerbrey M. & Richards F. (2011). Elimination of Human Ochocerciasis. History of progress and current feasibility using Ivermectin (mectizan) monotherapy. Acta Tropica 120 Supplement S100-8.
[12]  Thylefors, B. and Rolland, A. (1979). The risk of optic atrophy following Suramin treatment of occular onchocerciasis. Bull. World Health Organization 57(3): 479-480.
[13]  Francis, H., Awadzi k., Ottesen E.A. (1985). The Mazzoti reaction following treatment of Ochocerciasis with diethylcarbamazine: Clinical severity as a function of infection intensity. Am. J. Trop. Med. Hyg. 34(3): 529-536.
[14]  World Health Organization, WHO (1995). Onchocerciasis and its control, WHO Technical Report Series, N 852. World Health Organization, Geneva.
[15]  Njepuome, N., Ogbu-Pearce, P., Okoronkwo, C. & Igbe, M. (2014). Controlling onchocerciasis: The Nigerian experience. The Internet Journal of Parasitic Diseases. 4(1). Available@ Accessed 10/08/2016.
[16]  Maikaje, D. B., Dibal, D. M., Umar, Y. A. and Egbe, N. E. (2015). Investigations on the transmission potentials of Simulium damnosum and the risk of human onchocerciasis in Kaduna metropolis, Kaduna State, Nigeria. International Journal of Modern Biology Research, IJMBR 3: 1-5.
[17]  Katabarwa, M. N., Walsh, F., Habomugisha, P., Lakwo T. L. and Agunyo, S. (2012). Transmission of onchocerciasis in Wadelai focus of Northwestern Uganda has been interrupted and the disease eliminated. J Parasitol Res, 2012: 2012: 748540. PubMed: 22970347.
[18]  Tekle, A. H., Elhassan, E., Isiyaku, S., Amazigo, U. V., Bush, S., Noma, M., Cousens, S., Abiose, A. and Remme, J. H. (2014). Impact of long-term treatment of Onchocerciasis with ivermectin in Kaduna State, Nigeria: First evidence of the potential for the elimination in the operational area of the African Programme for Onchocerciasis control. Parasites and Vectors. 5(28):6.
[19]  Traore, M. O., Sarr, M. D., Badji, A., Bissan, Y. and Diawara, L. (2012) Proof-of-principle of onchocerciasis elimination with ivermectin treatment in endemic foci in Africa: Final results of a study in Mali and Senegal. PLOS Neg Trop. Drosophila Inf Serv 6: e1825.
[20]  Rodríguez-Pérez, M., A, Lizarazo-Ortega, C., Hassan, H., K, Domínguez-Vásquez, A. and Méndez-Galván, J. (2008). Evidence for suppression of Onchocerca volvulus transmission in the Oaxaca focus in Mexico. Am J Trop Med Hyg 78: 147-152.
[21]  World Health Organization (2001). Criteria for Certification of Interruption of Transmission/Elimination of Human Onchocerciasis. Geneva: World Health Organization. p. 64. Report. WHO/CDS/CPE/CEE/2001.18a.
[22]  Guevara, A. G., Juan, C. V., Bruce, G. L., Andrea, L., Nadia, V., Jose, R., Richard, C., Charles, R. K. and Thomas, R. U. (2003). Entomological evaluation by pool screen polymerase chain reaction of Onchocerca volvulus transmission in Ecuador following mass mectizan distribution. Am. J. Trop. Med. Hyg. 68(2): 222-227.
[23]  Garms, R. (1975). Observation on filarial infections and parous rates of anthropophilic blackflies in Guatemala, with reference to the transmission of Onchocerca volvulus. Tropenmed parasitol 26: 169-182.
[24]  Walsh, J. F., Davies, J. B., Le Berre, R. and Garms, R. (1978). Standardization of criteria for assessing the effect of Simulium control in Onchocerciasis Control Programme. Transactions of the Royal Society of Tropical Medicine and Hygiene, 72: 675-676.
[25]  Cheke, R. A. and Denke, A. M. (1988). Anthropophily, zoophily and roles in onchocerciasis transmission of the Djodji form of Simulium sanctipauli and S. squamosum in a forest zone of Togo. Trop. Med. Parasitol, 39: 123-127.
[26]  Cheke, R. A., Avissey, H. S., Sowah, S. A., Walsh, J. F. and Garms, R. (1992). The vectorial efficiency of Simulium yahense population in south-eastern Ghana. Trop. Med. Parasitol, 43: 62-64.
[27]  Iroha, I. R., Okonkwo, C. I., Ayogu, T. E., Oji, A. E. and Onwa, N. C. (2010). Epidemiology of human onchocerciasis among farmers in Ebonyi State, Nigeria. International Journal of Medicine and Medical Sciences. 2(8): 246-250.
[28]  Taye, A., Gabre Micheal, T. and Staticheff, s.(2000). Onchocereriasis in gigal ghibe river valley southwest Ethiopia, east west African medical journal, 77(2): 116-120.
[29]  Ubachukwu, P.O. and Anya, A.O. (2001). Effects of blackfly bites and manifestations of human onchcerciarsis on the productivity of farmers. Journal of tropical agriculture, food, environment and extension, 2(1): 9-16.
[30]  Crosskey, R. W. (1990). The Natural History of Blackflies. First Edition. John Wiley and Sons, New York.
[31]  Nworie, J. (2013). Vector dynamics in blackflies and evaluation of onchocerciasis in Ishielu L. G. A. MastersThesis, Ebonyi State University, Ebonyi State. African Medical Journal, 77(2): 116 - 120.
[32]  Wealtheral, N. (1995). Transmission potentials of Oncocerca volvulus and the associated intensity of onchocerciasis in Sudan Savanna area. Tropical Medical Parasitology. 29: 340-346.
[33]  World Health Organization (2015). Onchocerciasis. Fact sheet Nº374, updated July 2016. Available at:
[34]  Basáñez, M. G. and Boussinesq, M. (1999). Population biology of human onchocerciasis. Philos Trans R Soc Lond B Biol Sci. 354: 809-826.
[35]  Butler, J. F. and Hogsette, J. A. (1998). Featured creatures from Entomology and Nematology Department, UF/IFAS, Extensions, University of Florida, Gainesville, FL 32611. EENY-030 (IN157).
[36]  Alhassan, A., Makepeace, B. L., LaCourse, E. J., Osei-Atweneboana, M. Y. and Carlow, C. K. S. (2014). A Simple Isothermal DNA Amplification Method to Screen Black Flies for Onchocerca volvulus infection. PLoS ONE 9(10): e108927.
[37]  Lloyd, M. M., Gilbert, R., Taha, N.T., Weil, G. J., Meite, A., Kouakou, L. M. M. and Fisher, P. U. (2015). Conventional Parasitology and DNA-basic Diagnosticmethods for onchocerciasis elimination programmes. Tropica; 146: 114-118.
[38]  Doyle, S. T., Armoo, S., Renz, A., Taylor, M.J., Osei-Atweneboana, M. Y. and Grant, W. N. (2016). Discrimination between Onchocerca volvulus and O. ochengi filarial larvae in Simulium damnosum (s.l.) and their distribution throughout central Ghana using a versatile high-resolution speciation assay Parasit.Vectors 9:536.