The Prevalence and Distribution of Human Onchocerciasis in Two Senatorial Districts in Ebonyi State, Nigeria

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1 Americn Journl of Infectious Diseses nd Microbiology, 2014, Vol. 2, No. 2, Avilble online t Science nd Eduction Publishing DOI: /jidm The Prevlence nd Distribution of Humn Onchocercisis in Two Sentoril Districts in Stte, Nigeri Nworie Okoro 1, Ukpbi Nkechinyere Nwli 2, Oli Angus Nnmdi 3,*, Okonkwo Chum Innocent 4, Okoli Chukwudum Somdin 2, Ejiofor Obior Shedrck 5 1 Deprtment of Biologicl Sciences, Fculty of Science nd Technology, Federl University Ndufu-like, Ikwo, Stte 2 Deprtment of Applied Microbiology, Fculty of Biologicl Sciences, Stte University, Abkliki, Stte, Nigeri 3 Deprtment of Phrmceuticl Microbiology nd Biotechnology, Fculty of Phrmceuticl Sciences, Nnmdi Azikiwe University, Agulu Cmpus, Anmbr Stte, Nigeri 4 Deprtment of Ophthlmology, Federl Teching Hospitl, Abkliki, Stte, Nigeri 5 Deprtment of Peditrics, Anmbr Stte University Teching Hospitl, Amku, Awk, Anmbr Stte, Nigeri *Corresponding uthor: oli_n@yhoo.com Received Februry 02, 2014; Revised Mrch 08, 2014; Accepted April 27, 2014 Abstrct Bckground: There hs been recent increse in the number of humn Onchocercisis cses in hospitls in Centrl. This study therefore sets out to determine the prevlence of the disese in North nd Centrl Sentoril Zones of Stte s well s determine the ge groups nd sex most ffected. Methods: This study ws crried out in North nd Centrl Sentoril Zones of Stte between Jnury 2011 nd April 2012, mong subjects of yers. Dignosis ws by skin exmintion for onchocercl lesions, oculr exmintion for oculr lesion nd prsitologicl exmintion for the presence of microfilrie of Onchocerc volvulus in skin biopsies nd dult filrie in excised nodules. Results: Out of the 250 persons rndomly exmined in ech zone, 82 (32.8%) persons in Centrl zone comprising of 60 (38.7%) mles nd 22 (23.1%) femles were found positive for Onchocerc volvulus while 73 (29.2%) persons in North Zone comprising 48 (32.0%) mles nd 25 (25.0%) femles. Chi-squre test shows tht mle subjects hd significntly higher diseses prevlence (p < 0.05) thn their femle counterprts in the two zones but combined prevlence mong mle nd femle do not differ significntly in the two zones. The ge group most ffected ws yers with the prevlence of 40.0% in Centrl nd 38.6% in North Zones. Out of the 155 (30.8%) persons infected in the two zones, 28 (5.6%) mles nd 14 (2.8%) femles hd Onchocercl skin lesions, 57 (11.4%) mles nd 22 (4.4%) femles hd low vision. Prtil blindness ws observed in 16 (3.2%) mles nd 8 (1.6%) femles. However, 7 (1.4%) mles nd 3 (0.6%) femles hd complete blindness. Frmers were mostly ffected thn ny other occuptionl group. Conclusion: The findings obtined from this work suggested tht Centrl nd North Sentoril Zones re Onchocercisis hypo-endemic Zones hving the prevlence rte of 32.8% nd 29.2% respectively. Sex, ge nd occuption re relted to Onchocercisis infections in both Zones. Mles re more infected thn femles. Mssive distribution of insecticides to destroy the vector Simulium dmnosum (blck fly), provision of dequte ntiflril drugs - ivermectin nd mss helth eduction trgeted on preventive mesures re highly recommended. Keywords: onchocercisis, ebonyi stte, prevlence, neglected tropicl disese Cite This Article: Nworie Okoro, Ukpbi Nkechinyere Nwli, Oli Angus Nnmdi, Okonkwo Chum Innocent, Okoli Chukwudum Somdin, nd Ejiofor Obior Shedrck, The Prevlence nd Distribution of Humn Onchocercisis in Two Sentoril Districts in Stte, Nigeri. Americn Journl of Infectious Diseses nd Microbiology, vol. 2, no. 2 (2014): doi: /jidm Introduction Onchocercisis is n insidious non ftl filril disese tht hs cused blindness, lifelong humn suffering nd grve socio-economic problems [1]. Also known s river blindness or Robles disese, it is vector borne prsitic disese cused by the filril worm - Onchocerc volvulus [2]. It is one of the tropicl diseses clssified s orphn or neglected disese nd is the world s second leding infectious diseses [3,4]. The disese is clinicl syndrome prtly or entirely chrcterized by dermtologic, ophthlmologic, lymphtic nd sometimes systemic mnifesttions. The most serious lesions re those of the eye, which my led to prtil or totl loss of vision [5]. The vst mjority of infection occurs in sub-shrn Afric, lthough cses hve been reported in Yemen nd in smll foci in Centrl nd South Americ [6]. More thn 120 million people in 37 countries in Africn, Ltin Americ nd Yemen re t risk of the disese nd over 37

2 Americn Journl of Infectious Diseses nd Microbiology 40 million people hve been infected mostly those living in poor rurl communities [7]. Onchocercisis is currently endemic in 36 countries, 30 of them re in Afric, South of the Shr, in wide zone tht lies from Senegl to Ethiopi. The endemic re extends from South of the equtor to Angol in the West nd Tnzni in the est. Loclized foci exist in Sudn nd Yemen [6]. Through vrious control progrmmes led by the World Helth Orgniztion nd bsed on vector control nd/or mss dministrtion of ivermectin [8], the globl burden of the disese hs been considerbly reduced. More recently, ttention hs been focused on the Wolbchi orgnism, the endosymbiotic bcteri crried by dult worms nd microfilrie [9]. With ll these ttempts to control the infectious disese, Centrl zone still suffer from its burden nd the work-force in re hs been gretly ffected (Okonkwo nd Ejiofor unpublished dt). This study is set to scertin nd compre the prevlence of the infection in North nd Centrl Sentoril zones of Stte, Nigeri nd to determine the ge, occuptionl nd sex distributions of the disese in the re. It is expected tht this study will be n eyeopener to the government, non-governmentl orgnistions s well s community-bsed orgnistions to mount vrious intervention progrmmes (like ivermectin provision, helth eduction nd wter-wy/wter bodies decontmintions) nd help reduce the burden of the infection in the re. 2. Methods 2.1. The Study Setting nd Popultion The study ws crried out in Centrl nd North Sentoril Zones of Stte with popultion of 1,356,467 persons [10]. Centrl Sentoril Zone is mde up of the following Locl Government Ares (LGAs) viz: Ezz North, Ezz South, Ikwo nd Ishielu while North Sentoril Zone includes Abkliki,, Izzi nd Ohukwu L.G. As Stte is locted in the Estern prt of Nigeri nd is bounded to the North by Benue Stte, to the Est by Cross River, to the South by Abi Stte nd to the West by Enugu Stte. The stte lies between longitude 7 35 N nd ltitude 6 45 E. It experiences two sesons, riny seson (between April to October) nd dry seson (between November to Mrch). The vegettion of the re is chrcterized by trees, shrubs, grsses nd vegettive covers which re sprsely distributed. There re significnt ptches of swmp which form the bsis of their griculturl ctivities. There re ponds, strems nd other stgnnt wter bodies scttered ll over the re. It hs River which cuts cross these zones. These rivers serves s the breeding sites of the vector Simulium dmnosum whose consistent bites to the rurl dwellers who use these rivers s their source of wter for drinking, bthing, wshing nd other domestic ctivities, results to river blindness the most serious complictions of Onchocercisis. The study re is inhbited by different ctegories of people which include civil servnts, frmers, students, trders, drivers, lborers but the mjority is frmers who cultivte lrge quntities of rice, ym nd cssv. All these ctivities predispose them to the bite of the blck flies Smple Collection A smple size of 500 persons, mde up of mles nd femles mtched for ges, were recruited rndomly from the two zones. One hlf cme from one zone nd the other hlf cme from the other zone, ges were mtched. This smple size ws determined using Ymne (1973) [11] methods for clculting the smple size from finite popultion. n = N/ (1+ Ne 2 ), Where n = desired smple size, e = Mximum ccepted mrgin of error (0.05), N = Popultion = 1,356,467 persons [10], 1 = Theoreticl constnt, n = 1,356,467/ (1+ 1,356,467* 0.05* 0.05) = , The minimum number of prticipnts tht will give significntly significnt result is pproximtely 400 but the study used 500 ptients. The 500 prticipnts gve orl consent nd were interviewed in ntive lnguge to obtin demogrphic informtion such s ge, eduction nd occuption. This study minly involved physicl exmintions, dignosis nd ssessment of oculr nd skin Onchocercisis for ll the 500 prticipnts Skin Snip Biopsies/Nodule Excision This ws bsed on finding the microfilrie of Onchocerc volvolus in skin biopsies nd dult worm in excised nodules s described by Cheesbrough (2005) [12]. Skin snips ws septiclly tken from the body of ech ptient by lifting smll piece of the skin using sterile needle nd then cutting off with sterile rzor blde. The skin snips were then plced in conicl centrifuge tube contining bout 1 ml of the fresh physiologicl sline nd incubted for 4 hours. After incubtion, the content of the tube ws centrifuged t 500 to 1,000 Reltive Centrifugl Force (RCF) for 5 minutes. The skin snips nd sediments were exmined microscopiclly for microfilrie of Onchocerc volvolus using x10 mgnifiction. When smples re positive, microfilrie re seen wriggling in the sline Assessment of Skin Onchocercisis The 500 ptients were physiclly exmined for obvious signs of Onchocercisis such s hnging groin, elephntisis, depigmenttion (leoprd skin), visible nd plpble nodules, pruritis s well s derml fibrosis nd trophy Assessment of Oculr Onchocercisis The visul cuity t fr nd ner distnce ws tested using E chrt nd bility to count figures t distnce up to 6 m. The interior eye ws exmined for free floting introculr microfilri using ophthlmoscope Mterils Rzor blde (Nsset, Nigeri), needles, glss slide, cover slip, centrifuge (Hermie Lbortechnic, Germny), incubtor (Binder Lbortechnic GMbH, Germny),

3 41 Americn Journl of Infectious Diseses nd Microbiology microscope (Electromtic Ltd/Gillett nd Sibert, Scotlnd), glss tube Other Mterils Snellen s visul cuity chrt, pen light nd Ophthlmoscope Sttisticl Anlysis The dt obtined were nlyzed by percentges, br chrts, Chi-Squre test nd One Wy ANOVA with Tukey's Multiple Comprison pre-test Consent All uthors declre tht verbl informed consent ws obtined from the ptient for publiction of this report nd ccompnying imge Ethicl Approvl The uthors hve obtined ll necessry ethicl pprovl from the ethics committee of Anmbr Stte University Teching Hospitl, Amku in Awk. This confirms either tht this study is not ginst the public interest, or tht the relese of informtion is llowed by legisltion. All uthors hereby declre tht ll experiments hve been exmined nd pproved by the pproprite ethics committee nd hve therefore been performed in ccordnce with the ethicl stndrds lid down in the 1964 Declrtion of Helsinki. 3. Results nd Discussion The summry of the prevlence of Onchocercisis in ll the LGAs of the two Sentoril Zones is shown in Tble 1 below. Sentoril Zone bonyi North Centrl Locl Government Ares Nodules Tble 1. Onchocercl Lesion Mnifesttion in Different LGAs Lesions Low Prtil Leoprd Hnging Dermtitis Vision Blindness Skin groin Blindness Ezz North Ezz South Ikwo Ishielu number infected (%) 4 (1.6) 6 (2.1) 9 (3.6) 1 (0.4) 4 (16.4) 14 (5.6) 7 (2.8) Abkliki Izzi Ohukwu (0.8) 5 (2.0) 15 (6.0) 0 infected (%) This study reveled totl prevlence rte of 31.0% in the two Sentoril Zones. Centrl Sentoril Zone hd 32.8% rte of infection while North Sentoril Zone hd 29.2% prevlence. This study revels higher Onchocercisis prevlence in the re compred to 26.9% previously reported [13] in Onchocercisis endemic re of Enugu stte but lower prevlence compred to 33.35% reported [14] in Stte generlly. The lower prevlence seen in this study my be due to little public wreness cmpign/eduction on-going in North sentoril zone. This study nd erlier ones shows the urgent ttention needed to curtil the burden of the disese in the two sttes. A Chi-Squre test shows tht there is no significnt difference in prevlence of the infection in the two zones ( North nd Centrl) t α < 0.5 significnt level (P vlue = ). One-wy nlysis of vrince of the number of cses of the disese (prevlence) in the different Locl Government Ares (L.G.As) shows tht there is no significnt difference in the prevlence rte of the disese in the L.G.As (P = ). Reports [15,16] show tht the occurrence of Onchocercisis vries from one geogrphicl region to nother nd these zones belong to common region. The prevlence of Onchocercisis in Nigeri hs significnt vrition in different villges with 38 (15.2) 10 (4%) 3 (1%) Infected 20 (36.4%) 21 (29.5%) 24 (40.6%) 17 (26.1%) 82 (32.8%) 14 (28.0%) 17 (32.2%) 23 (29.8%) 19 (27.1%) 73 (29.3%) Exmined the villges tht re ner the breeding sites of vector showing higher infection prevlence [17]. Centrl Zone hd higher Onchocercisis prevlence rte of 32.8% (lthough not sttisticlly significnt) thn North Sentoril Zone with 29.2% occurrence. This is so becuse Centrl Zone is known for their frming ctivities, being nturlly endowed with swmp nd the River. Another occuptionl predisposing fctor to the higher prevlence of the disese in Centrl is the digging of snd from the river for commercil purposes. These unskilled workers dig nd crry snd from the river bnks to sell to buyers who use the snd for building purposes. These ctivities (crried out by men only) expose them more to the bite of the infected blck fly. (See Tble 3 nd Figure 1 below). The study (Tble 4) lso show tht frmers hd significntly (p < 0.05) higher prevlence rte thn trdes, civil servnts, drivers or students with higher prevlence rte of 22.8% for Centrl Zone thn North Zone (21.6%). Field workers re more predisposed to the bite of the infected blck fly [14,17]. Tukey's Multiple Comprison Test of Occuptionl Distribution of Onchocercl Lesion (Figure 1) below shows tht there is significnt difference in the prevlence

4 Americn Journl of Infectious Diseses nd Microbiology 42 of the disese between "Trders versus Frmers", "Trders versus Students", "Frmers versus Students" nd "Frmers versus Civil Servnts" but not between Trders versus Civil Servnts nd Students versus Civil Servnts t α < It is understndble tht Trders re next to Frmers in high prevlence s mny of these trders engge in snd digging trde. Figure 1. Occuptionl Distribution of Onchocercl Lesion The prevlence of Onchocercisis ws significntly higher (p<0.05) mong mles (35.41%) thn femles (24.10%) subjects in the two Zones combined (Tble 2). In Centrl Zone, % mles nd % femles were infected while in North Zone, it ws 32 % nd 25 % respectively. The differences in infection rte with regrds to sex my be due to endemicity [17], occuptionl exposure nd susceptibility of individul [14,18]. Mles work longer in the frm, nd with bre body, thn the femles thereby mking them more prone to the bite of the blck flies. Also, they re the ones involved in snd digging. The findings in this study differ from nother report [15] in Ovi North Est L.G.A of Edo Stte Nigeri where femles hd 93% Onchocercisis infection nd mles 74.5%. Rmpnt prctice of Onchocercl nodules excision by ntives hve been observed in Nigeri [19]. The yers ge group hd the highest rte of Onchocercisis with (21.6% in the Centrl Zone nd 16.0% in the North Zones (Tble 3). This could be becuse this ge group is mostly frmers. The mnifesttion of Onchocercl lesions follows the sme pttern in their distribution in the two zones. A similr observtion to the findings of this study hs been reported [20,21]. Onchocercl lesions such s Nodules, leoprd skin, hnging groin nd blindness were observed in subjects exmined. Pruritis/dermtitis (Figure 2) 24 (4.8%) ws found in ll ge groups but is higher in the older ge groups of yer. Leoprd skin ws found in 11 (2.2%) ptients, Nodules in 6 (1.2%) persons, nd Hnging groin in 1 (0.2%) ptient exmined. Onchocercisis lesions mnifesttion ws more in mles thn femles especilly in Centrl Zone with subjects from yers showing higher Onchocerc volvulus infection (Tble 1). The prevlence of physicl symptoms ws low nd similr observtion hs been reported [22]. Our findings reveled tht visul cuity impirment nd blindness ws significntly different (P < 0.05) in the two Sentoril Zones. Low vision hd the highest occurrence (12.0%) in both Zones followed by prtil blindness (4.6%). North Sentoril Zone hd higher prevlent rte thn Centrl Sentoril Zone. Blindness which ws the most serious compliction of Onchocercisis hd low prevlence rte (2.4%) in both Zones. Centrl Sentoril Zone hd 7 (2.8%) persons who were ffected while North Sentoril Zone hd 3 (1.2%) persons ffected (Figure 3 nd Tble 1). The low occurrence of blindness in this study ws in contrst to the high blindness rte previously reported [23,24] in the Svnn res. This difference in prevlence rte of blindness ccording to report [25] ws ttributed to the more invsiveness nd pthogenic nture of microfilrie strin of Svnnh for the corne thn those of the rinforest strin. Lck of vitmin A encourges the free spred of microfilrie through the tissues especilly the eyes leding to blindness [26], hence the low blindness rte in this study my be ttributed to incresed consumption of vitmin A through plm oil by the people living in Centrl nd North Sentoril Zone. Mles recoded high blindness prevlence rte thn femle subjects in both Zones. The lower incidence of Onchocercl blindness nd other lesions in the femles ws ttributed to possible unexplinble hormonl effects [27]. Tble 2. Sex Distribution of Onchocercl Lesions in the two Sentoril Zones Sentoril Zone Gender Nodules Leoprd Skin Dermtitis Lesions Hnging groin Low Vision Prtil Blindness Blindness Infected Exmined Percent Infected Centrl Mle Femle North Mle Femle

5 43 Americn Journl of Infectious Diseses nd Microbiology Sentoril Zone Centrl North Tble 3. Onchocercisis Mnifesttion by Age Age Lesions Group Leoprd Hnging Low Prtil Nodules Dermtitis (Yers) Skin groin Vision Blindness Blindness Infected Exmined (8.8) (13.6) (21.6) (18.8) 65 (%) 39 4 (1.6) 6 (2.4) 9 (3.6) 1 (0.4) infected (15.6) 14 (5.6) 82 (32.8) 155 (62.0) (14.4) (13.6) (16.0) (13.2) 44 (%) infected 2 (0.8) 5 (2.0) 15 (6.0) 0 (0.0) 38 (15.2) 10 (4.0) 73 (29.2) 143 (57.2) 250 Sentoril Zone North Centrl Tble 4. Occuptionl Distribution of Onchocercl Lesion Locl Government Ares Occuption Trders Frmers Students Civil Servnts Infected Exmined Ezz North (36.36) 55 Ezz South (29.57) 71 Ikwo (42.85) 56 Ishielu (26.15) 65 (%) infected 14 (5.6) 57 ( (1.6) 7 (2.8) 82 (32.8) 250 Abkliki (28.00) (32.08) 53 Izzi (29.87) 77 Ohukwu (27.14) 70 (%) infected 11 (4.4) 54 (21.6) 3 (1.2) 5 (2.0) 73 (29.2) 250 As shown in FIGURE 2 below, of the 250 ptients exmined for visul cuity in Centrl Sentoril Zone, 7 (2.8%) ptients were blind (2/60) while 14 (5.6%) ptients hd visul cuity of between 5/60-3/60 which indictes prtil blindness, 41 (16.4%) ptients hd visul cuity of between 6/24 6/60 which is low vision. In North Sentoril Zone, out of 250 ptients exmined, 3 (1.2%) ptients re blind (2/60) while 9 (3.8%) ptients hd prtil blindness (5/60 3/60) nd 38 (15.2%) ptients hd low vision (5/24-6/60). A t - test nlysis of the result, t α < 0.05 level of significnce, shows tht there is no sttisticl difference in the visul cuity levels of the prticipnts from the two zones in Stte (P vlue = ). Figure 3 below shows the picture of ptient with leoprd skin observed during the study. The leg is scly nd very itchy. Figure 3. Picture of ptient with leoprd skin (shin depigmenttion) observed during the study 4. Conclusion Figure 2. Distribution of Visul Acuity mong Onchocercisis Infected Persons between Yers in Centrl nd North Zones The findings obtined from this work suggested tht Centrl nd North Sentoril Zones re Onchocercisis hypo-endemic Zones hving the prevlence rte of 32.8% nd 29.2% respectively. Sex, ge

6 Americn Journl of Infectious Diseses nd Microbiology 44 nd occuption re relted to Onchocercisis infections in both Zones. Mles re more infected thn femles. In view of these findings, it is recommended tht: 1. Government t ll levels should give Onchocercisis progrmme high priority nd prticulrly so in Centrl Zone. 2. Tht Ivermectin drug should constntly be mde vilble nd ccessible to the people. 3. Tht wreness cmpign should be crried out in the re through electronic medi nd helth eductors. 4. Efforts should be mde to erdicte the vector fly by sprying chemicls long the wter-wys nd up on the wter bodies using helicopters. List Of Abbrevitions 1. Locl Government Ares (LGAs). 2. Reltive Centrifugl Force (RCF). 3. Africn Progrmme for Onchocercisis Control (APOC). Competing Interests The uthors declre tht they hve no competing interests. Authors Contributions Nworie Okoro conceptulized the study, Ukpbi Nkechinyere Nwli implemented the study nd interpreted the dt, Oli Angus Nnmdi wrote the first drft nd did prt of the sttisticl nlysis, Okonkwo Chum Innocent ws the Medicl doctor tht exmined the ptients nd dignosed the disese, Okoli Chukwudum Somdin designed the study while Ejiofor Obior Shedrck criticlly red the drft for intellectul content. Endnote Clssifiction of blindness Good vision = 6/9-6/18, Low vision = 6/24-6/60, Prtil blindness = 5/60-3/60, Blindness = 2/60 [28]. References [1] Gerld, D.S nd Lny, S.R. (2010) Foundtions of Prsitology: McGrw-Hill, New York. Eight Editions. pp [2] Tekle, A.H., Elhssn, E., Isiyku, S., Amzigo, U.V; Bush, S., Nom, M., Cousesns, S., Abiose, A. nd Remme, J.H. Impct of long-term tretment of Onchocercisis with Ivermectin in Kdun Stte, Nigeri: First evidence of the potentil for elimintion in the opertionl re of the Africn progrmme for Onchocercisis Control. Prsite nd Vector; 2012, 5: [3] Thylefors, Bjo rn I, Négrel, A. D, Prrjsegrm Rmchndr nd Ddzie, K. Y Globl dt on blindness. Bulletin of the World Helth Orgniztion; 1995, 73 (1): [4] Pion, S.D., Kmgno, J., Demng-Ngngue nd Boussinesq, M.E. Excess Mortlity ssocited with blindness in the Onchocercisis focus of Mbm vlley, Cmeroon. Ann. Trop. Med. Prsitol; 2002, 96 (2): [5] Nwoke, B.E.B. Ivermectin, the incredible Drug ginst Humn Onchocercisis. Medicre Journl; 1992, 5: 1-2. [6] World Helth Orgniztion. Sttus of Onchocercisis in Africn Progrmme for Onchocercisis Control (APOC) Countries, TDR /AFR/RP/951.6, Genev, [7] World Helth Orgniztion. Onchocercisis nd its control. Report of WHO Expert committee on Onchocercisis control. WHO Technicl Report series; 1995, 852: Genev. [8] Tielsch, J.M nd Beech, A. Impct of ivermectin on illness nd disbility ssocited with Onchocercisis. Trop. Med. Int. Helth; 2004, 9 (4): [9] Hoeruf, A.,Buttner, D.W., Adjei, O nd Perlmn, E. 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