Advances in Biomedicine and Pharmacy (An International Journal of Biomedicine, Natural Products and Pharmacy)

ISSN: 2313-7479 Adv. Biomed. Pharma. 3:3 (2016) 166-172 Advances in Biomedicine and Pharmacy (An International Journal of Biomedicine, Natural Products and Pharmacy) Case Study Prevalence of Onchocerciasis and Efficacy of Ivermectin: a brief study from Idogun, Nigeria. Afolabi Olajide Joseph Department of Biology, Federal University of Technology Akure, Nigeria. *Corresponding Author: Afolabi Olajide Joseph Department of Biology, Federal University of Technology Akure, Nigeria. E-mail address: jideafo77@gmail.com; Tel; 234(0)8035959391 Running Title: Prevalence of Onchocerciasis and Efficacy of Ivermectin Received: 05 May, 2016; Revised: 10 June, 2016 Accepted: 21 June, 2016 Available online at http://www.thescientificpub.com http://dx.doi.org/10.19046/abp.v03i03.06 Abstract Onchocerciasis is an eye and skin infection caused by a filarial worm: Onchocerca volvulus and transmitted by haematophagous female Simulium blackfly. The present study was carried out in Idogun; an endemic community in Ose local government area, Ondo State, to investigate the prevalence of onchocerciasis and the efficiency of Ivermectin drug. Simple random sampling technique was employed in selecting 384 respondents of both genders not below 10 years of age that attended the community health centre and a structured questionnaire was used to obtain epidemiological information. Skin snips aseptically obtained from the respondents were prepared for microscopy using sedimentation method and subsequently viewed under X10 objective lens of light microscope. The results showed that the prevalence of the disease was significantly different among the age groups and genders (P <0.05) with highest prevalence of the disease (43.6%) observed in age group of 51-60 years while the lowest prevalence (0%) was observed in age group 81-90years. Meanwhile, highest average microfilarial load (12.2mf/mg) was observed in age group 71-80years while the lowest average microfilarial load (0mf/mg) was observed in age group 81-90years. Similarly, the prevalence of infection (M=29.4%, F=26.5%) and average microfilarial load of the parasite (M=8.2mf/mg, F=7.6mf/mg) were significantly higher in male than the female gender. The drug (ivermectin) was observed to be effective in the community but the efficiency varied significantly among the age groups (P<0.05). The highest efficiency of the drug (87.5%) was observed in age group 21-30years while the lowest efficiency (16.5%) was observed in age group 71-80years. The results revealed that the community is still endemic for river blindness; hence there is need for continuous distribution of the drug in the community in order to completely eradicate the disease. Keywords: Onchocerciasis, Prevalence, Ivermectin, Idogun, Efficiency. Introduction Onchocerciasis also known as river blindness is a parasitic disease caused by a filarial nematode (Onchocerca volvulus) and vectored by a female Simulium blackfly. The disease is endemic in 28 countries of Africa, 6 countries in the Americas and in Yemen. Some 18 million people are estimated to be infected worldwide and over 99% of them are living in Africa [1] In Africa, hyper endemic villages can have infection rate of 100%, 10% of the entire village may be blind, including up to 50% of those aged 40 years 166 and older [2]. An estimated 40 million people are at risk of the infection worldwide with approximately 500,000 people blind due to onchocerciasis [3]. The clinical manifestations of onchocerciasis vary from one geographical region to another, although, there are general manifestations of the disease that are common in patients such as papules, pruritus, ocular lesions, lizard skin and leopard skin [4]. The disease has been noted to be a major obstacle to the development in endemic areas especially in Africa. The fear of river blindness has made farmers to abandon fertile land which would have been cultivated for

Advances in Biomedicine and Pharmacy Vol. 3 (3) 2016 agricultural products. This has resulted into low productivity, low income and higher related cost of treatment among infected adults. Treatment of onchocerciasis has been a major impedance in the past towards control measures of the disease in the endemic areas but with the advent of drugs such as Suramin, DEC (diethylcarbamazine) and more recently Ivermectin [5]. The morbidity and mortality associated with the disease has drastically reduced in the endemic communities. It should be noted that at the same time these drugs have their peculiar side effects. For instance, because of the slow excretion of Suramin, it has been reported to have severe cumulative effects on the recipients [5]. Likewise, in patients with ocular lesion, DEC aggravates the condition and can cause complete loss of vision [6]. However, Ivermectin has been discovered to be the drug of choice for onchocerciasis because it has an effective microfilaricidal effect that could clear microfilariae from the skin with minimum side effects [7-9]. This drug (ivermectin) has been widely distributed in communities where the disease is endemic to eliminate the disease. The present study is intended to investigate the prevalence of infection identify the individuals requiring treatment, evaluate the success of treatment, and to assess the impact of control efforts. Subjects and Methods The study was carried out in Idogun, an endemic community in Ose Local Government of Ondo State. Idogun is a forest zone located in the northern zone of Ose LGA of Ondo State. The community is a semi-urban settlement characterized with rainfall season from April to September with annual rainfall of 1524 mm, temperature range of 28-31 C and mean annual relative humidity of 80%. Socio-economic activities in the community include farming (which is the predominant occupation in the community), hunting, trading and civil service. Ethical Clearance and Informed Consent Before the commencement of the study, an approval for the study was obtained at the Ondo State Ministry of Health, Ose Local Government Area and community head. Informed consent of the respondents was obtained after focus group discussion in local language, where they were enlightened on the aetiology, pathology, control and prevention of the disease in the community. Individuals who attended the public health clinic in Idogun and gave their consent to participate in the study were considered for the study. 167 Laboratory Analysis of Skin Snips Afolabi Olajide Joseph. Three hundred and eight-four (384) participants of both sexes and not below 10 years of age who attended the community clinic and gave their consent to participate in the study were considered for the study. A Structured questionnaire was prepared to obtain useful epidemiological information from the respondents such as sex, age, weight and occupation. The bloodless snips collected from the respondents were placed in 0.5 ml normal saline in a microtitre plates and left for 4 hours to allow the microfilariae to migrate out of the tissues. The solution was centrifuged at 2000 rpm for 15 min., the sediment obtained was smeared on sterile slides and stained with Giemsa at ph 6.8. The smears were examined for microfilariae under microscope at X10 objective lens. The number of snips positive for the microfilariae were noted among the age groups and genders. Efficiency Test The Ivermectin which is the drug of choice for onchocerciasis was administered to the respondents who had never taken the drug before. The individuals for the test were clinically examined for papules and skin snips were taken from them. The skin snips were examined under the microscope to establish infection. The weights of the individuals were taken with the aid of weighing balance and the drug was administered orally using WHO approved standard. According to the mentioned standard information 0.15mg/kg should be administered twice a year and each dose of the drug weighed 3g. Hence the average dose per body weight was calculated using the below formula: Average Dose of Ivermectin = 0.15mg/kg X Body Weight 3mg/dose The efficiency of Ivermectin was also calculated by comparing the prevalence of infection before and after treatment divided by the prevalence before treatment multiply by 100 i. e Efficiency = Prevalence before treatment Prevalence after treatment X 100 Statistical analysis Prevalence before treatment Data obtained from age prevalence and efficiency of the drug were subjected to One-Way ANOVA. Data from gender prevalence were analyzed using Carls Pearson Chisquare while data from drug efficiency were subjected to T-test, where there are differences in means, the means were separated using New Duncan Multiple Range Test. All the analyses were done using Statistical Package for Social Sciences (SPSS) version 20.0 and 95% level of significance.

Prevalence of Onchocerciasis and Efficacy of Ivermectin Advances in Biomedicine and Pharmacy Vol. 3 (3) 2016 Results Laboratory diagnosis of the disease using skin snip revealed that the disease was found in all age groups with exception of age group 81-90 years although with varying prevalent rates. The oldest age group (81-90years) where the parasite was absent comprises mainly the retirees who have little or no contact with the river. Prevalence of disease was found to increase as the age group increases to 60years and later decreases as the age group increases further as shown in Table 1. This distribution pattern of the disease observed in this community might be as a result of increase in exposure of the respondents to the river viz a viz risk factors such as farming, hunting and swimming. The highest prevalence of the disease (41%) was found among the age group of 51-60 years while the lowest or no prevalence (0.0%) was expressed in the age group 81-90 (Table 1).Out of the 384 respondents examined for Onchocerca volvulus in the community, 108 (28.1%) were positive while 272 (71.9%) were negative. The total recoverable worm among the infected persons in the community was 859mf/mg meanwhile the average microfilarial load of the parasite was observed to be significantly different among the age groups with 71-80years of age recording the highest average microfilarial loads (12.2mf/mg) while the lowest average microfilarial load (0.0mf/mg) was observed among the age groups of 81-90years. Prevalence and average microfilarial load of the parasite were significantly higher in male gender (29.4%, 8.6mf/mg) than the female gender (26.5%, 7.6mf/mg) (Table 2). This might be because males are more exposed to the risk factors of the disease than the females. Socio-economic activities as observed among the respondents in the community include: farming, trading, artisan, hunting, schooling, civil service etc. Among these activities, farming and hunting either practise at part-time or full time increase the chance of someone contacting river blindness especially when these are done around the river bank. This is because the blackflies that act as the vector of the parasite breed in the flowing river and have a short flight range of about 10km. Therefore the proximity of man to the river increases the prevalence and the intensity of the parasite (O. volvulus) in the host. In addition, the prevalence and intensity also increases as the frequency of exposure increases. The prevalence of the disease was highest among the farmers (39%), closely followed by hunters (37.5%). Prevalence of 16.7%, 16.0% and 14.3% were found among traders, students and housewives respectively (Table 3). The lowest prevalence (9.6%) was observed among the artisans, this is because the artisans spend most of their time in the shop or workshop. It was generally observed that activities that reduce proximity to the river have lower prevalence compared to those activities that increase proximity to the river. The efficiency of Ivermectin among the study groups showed that the drug was more effective at lower age groups (10-50years) than the older age groups (51-90years). As observed from Table 4, the highest efficiency (33.5%) after 6 month treatment was recorded in age group 31-40years while the lowest efficiency (0%) was recorded in age group 71-80years. Generally, increase in drug efficiency with varying degrees was observed among the age groups after 12months treatment. Efficiency after 12months treatment showed that age group 21-30years had the highest efficiency (87.5%) while the lowest efficiency (16.5%) was observed in age group of 71-80years. Age group of 81-90years was not considered in the efficiency test because all the individuals in this age group were negative to the infection. Table 1: Prevalence of Onchocerciasis among Different Age Groups in Idogun Community. Age Group No. Examined No. Positive Prevalence MF Av. MF (Years) (% ) (mf/mg) (mf/mg) 10-20 24 04 16.7 31 7.8 21-30 40 08 20.0 39 4.9 31-40 30 06 20.0 58 9.7 41-50 100 28 28.0 154 5.5 51-60 78 34 43.6 323 10.1 61-70 66 16 24.4 132 8.3 71-80 36 12 33.3 146 12.2 81-90 10 0 0.0 0 0 Total 384 108 28.1 883 8.2 No.= Number MF = Microfilarial load AV. MF = Average Microfilarial load F value = 5.32 P value = 0.001** 168

Advances in Biomedicine and Pharmacy Vol. 3 (3) 2016 Afolabi Olajide Joseph. Table 2: Prevalence of Onchocerciasis between Genders in Idogun Community. Sex No. Examined No. Positive Prevalence (%) MF (mf/mg) AV. MF (mf/mg) Male 218 (56.8%) 64 29.4 548 8.6 Female 166 (43.2%) 44 26.5 335 7.6 Total 384 (100.0%) 108.0 28.1 883 8.2 No.= Number MF = Microfilarial load AV. MF = Average Microfilarial load χ 2 = 73.500 P value = 0.000** Table 3: Socio-economic Activities and Prevalence of Onchocerciasis in Idogun Community. Activities No. interviewed No. Positive Prevalence (%) MF(Mf/Mg) AV.MF(Mf/Mg) Farmers 172 67 39.0 588 8.8 Traders 60 10 16.7 59 5.9 Retirees 10 01 10.0 06 6.0 Artisans 52 05 9.6 27 5.4 Hunters 48 18 37.5 134 7.4 Housewives 07 01 14.3 5.0 5.0 Students 25 04 16.0 28 4.0 Govt. Employee 10 02 20 12 6.0 Total 384 108 28.1 859 8.0 T value = 1.654 P value = 0.142 NS Table 4: The Efficiency of Ivermectin among the Respondents in Idogun Community. Age Group Number Infected Number Infected after Efficiency (%) Number Infected after Efficiency (Year) before treatment 6months (Prev.) ± SE 12months (Prev.) (%) ± SE (Prev.) 10-20 4(16.7) 3 (12.5) 25.1 d ±0.37 1(4.2) 74.9 d ±1.65 21-30 8(20) 6 (15) 25 d ± 0.54 1(2.5) 87.5 e ±1.89 31-40 6(20) 4 (13.3) 33.5 e ±1.31 2(6.7) 66.5 d ±1.37 41-50 28(28) 25(25) 10.7 c ±0.39 16(16) 42.9 c ±1.52 51-60 34(43.6) 32(41.0) 6.0 b ± 0.37 26(33.3) 23.6 b ±1.71 61-70 16(24.4) 15(22.7) 7 b ±0.36 12(18.2) 25.4 b ±1.32 71-80 12(33.3) 12(33.3) 0 a ±0.0 10(27.8) 16.5 a ±1.27 Total 108(28.1) 97(25.3) 10.0 68(17.7) 37.0 F value = 18.000 P value = 0.000** Discussion The infection rates were lower among the younger age groups (10-50years) than the older age groups (51-80years). This suggests that the older age groups are more susceptible to the infection as these age groups are actively involved in activities such as farming, hunting, lumbering 169 and fishing. This finding was similar to the reports of other authors [10] who reported that infection rates in Owan west LGA of Edo State, Cross River, Kogi and Taraba respectively increases with age. Similar results were also

Prevalence of Onchocerciasis and Efficacy of Ivermectin Advances in Biomedicine and Pharmacy Vol. 3 (3) 2016 reported by Adewole and Ayeni [11] in Ise-Orun Local Government in Ekiti State and Afolabi et al. [12] in Imeri community of Ose Local Government Area of Ondo State. Both authors in their separate studies reported higher prevalence of onchocerciasis among respondents above 50years of age than the respondents below age group 50years. Meanwhile, the result of this finding was contrary to the report of Umeh et al. [13] who reported prevalence of 18.6%, 18.6% and 20.7 % as the highest age prevalence in age group 15-24years in Cross River, Taraba and Kogi respectively. This disparity might be as a result of climatic differences between the forest and the savannah zones. In the northern part of the Nigeria which is characterized by savannah vegetation, the younger age groups are engaged more in farming than the older age groups while in the southern part of the country the case is reverse. In addition, the strains of the parasite vary according to the vegetation that is predominant in a particular location. In the forest zones where the study area is located the forest strain of the parasite is the most common and induced more dermal symptoms of the disease while the savannah strain of the parasite is predominant in the northern zone of the country and induces more ocular symptoms. The prevalence of onchocerciasis and the intensity of the parasite were significantly higher among the male than the female (p<0.05). This shows that the male gender engaged more in socio-economic activities that predisposed them to the infection then their female counterpart. This finding was in accordance with the findings of other groups [10, 12-14]. But contrary to the report of Ikechukwu et al. [15] who reported that the sex prevalence in upper river basin in Imo State was not different between the gender. Similarly, farming, fishing and hunting were identified as major socio-economic activities that highly predisposed the respondents to the infection. Higher infection rates and intensities (worm load) were also recorded among the farmers and hunters than other socio-economic groups in the community. This suggests that individuals that are engaged in activities such as farming and hunting especially around the river are likely to be exposed to the blackfly bites and consequently have higher infection rate and worm loads (intensity) as observed in Idogun community. This was in agreement with the finding of Ikechukwu et al. [15], who reported prevalence of 46.6% among the farmers in Imo State. The total prevalence of infection in Idogun (28.1%) community suggests that the community is hypo-endemic (16-39%). Furthermore, the present study revealed that the efficiency of the drug was significantly different among the age groups (p<0.05). The drug was found to produce significant effects among the younger age groups (10-50years) than the older age groups (51-90years) in the community both at 6 months and 12 months post treatments. These differences might be as a result of increase in microfilarial load (intensity) as the infected individuals advanced in age without treatment. The total efficiency as observed after 12 months post treatment in Idogun was 38.8% which suggests that the drug has a low rate of eliminating the worms from the host body. Therefore, for the microfilariae to be completely eliminated from the infected persons the drug must be taking continuously for many years. Conclusion To achieve a meaningful progress in disease control and prevention, health education especially in local languages should be intensified in endemic areas. The study identified age groups 51-60years as the age group that was more susceptible to onchocerciasis while farming and hunting were identified as activities that highly predisposed individuals in these communities to high risk of infection. Hence it is suggested that in community directed treatment with ivermectin (CDTI) these groups should be given more attention. The public enlightment among these age groups especially those with the clinical symptoms will further educate them of the need to consistently take the drug in order to avoid permanent blindness. Acknowledgements The authors are grateful to the Ondo State Ministry of Health for providing the drug (Ivermectin) used for this research. We are also grateful to His Royal Highness, the king of Idogun for granting the use of his town for the study and for his help in mobilizing the subjects during the public lecture. We are grateful to Dr Olawanle, the public health coordinator, Chief Ajileye, community public health chairman, Mrs Adelakun; the public health coordinator in Idogun; and Mr Babatunde, the community drug distributor for their cooperation during this study. Conflict of Interest The authors declare that there is no conflict of interest. 170

Advances in Biomedicine and Pharmacy Vol. 3 (3) 2016 Afolabi Olajide Joseph. References [1] Eezuduemhoi D and Wilson D., Onchocerciasis, emedicine., 2006. Available online at:http://medicine.medscape.com/article/1204593-overview. [2] Njepuome N, Ogbu-Pearce P and Okoronkwo MI., Controlling onchocerciasis. The Nigerian Experience, Int. J. Parasitic Dis., 4: 1-4, 2009. [3] World Health Organization., The onchocerciasis control program in West Africa, Public Health in action, 5: 1-20, 1994. [4] Afolabi OJ, Okaka CE and Oniya MO., Clinical manifestations of onchocerciasis in Imeri; an endemic community in Nigeria, Am. J. Res. Comm., 3: 249-259, 2015. [5] Magdi MA.,. Immunologic Aspect of Human Onchocerciasis, Stockholm, ISBN 91-7155-202-2: 1-68pp, 2006. [6] Bird AC, El-Sheikh H, Anderson J, Anderson J and Fuglsang H., Changes in visual function and in the posterior segment of the eye during treatment of onchocerciasis with diethylcarbamazine citrate, Br. J. Ophthal., 64: 191-200, 1980. [7] Awadzi K., The chemotherapy of onchocerciasis II. Quantitation of the clinical reaction to microfilaricides, Ann. Trop. Med. Parasitol., 74: 189-197, 1980. [8] Aziz MA, Diallo S, Diop IM, Lariviere M and Porta M., Efficacy and tolerance of ivermectin on human onchocerciasis, Lancet., 2: 171-173, 1982. [9] Campbell WC., Ivermectin as an antiparasitic agent for use in humans, Annu. Rev. Microbiol., 45: 445-474, 1991. [10] Wogu MD and Okaka CE., Prevalence and socioeconomic effects of onchocerciasis in Okpuje, Owan West Local Government Area, Edo State, Nigeria, Int. J. Biomed Health Sci., 4 :113-119. 2008. [11] Adewole SO and Ayeni SK., Clinical Manifestation of Onchocerciasis in Ise- Orun Local Government, Ekiti State, Nigeria, Pak. J. Nutr., 8: 122-124, 2009. [12] Afolabi OJ, Okaka CE, Simon-Oke IA and Oniya MO., Update Assessment of Prevalence of Onchocerciasis in Imeri, an Endemic Village in Ondo State, Southwest Nigeria, Nat. Sci., 12:146-149, 2014. [13] Umeh RE, Mahmoud AO, Hagan M, Wilson M, Okoye OI et al., Prevalence and distribution of ocular onchocerciasis in three ecological zones in Nigeria, Afr. J. Med. Med. Sci., 39:267-275, 2010. [14] Adeyeba OA and Adegoke AA., Onchocerciasis in communities in forest zone, Southwest Nigeria. Prevalence and diagnostic method for rapid assessment, African J. Clin. Exp. Microbiol., 3: 29-32, 2002. [15] Dozie I, Onwuliri C and Nwoke B., Onchocerciasis in Imo State, Nigeria: The Prevalence, Intensity and Distribution in the upper Imo River Basin, Int. J. Environ. Health Res., 14:359-369, 2004. 171

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