PDF File - The Indian Society for Parasitology

38Edward and Bernardtopographical features of the study areas have been volvulus was carried out in whole population of thedescribed by Nwoke et al. (1998) as being favourable Etulo area; however, this was not possible in Okpokwuand suitable for onchocercosis transmission.LGA as a result of immunological and parasitologicalstudies just concluded in the same area by Amuta andOkpokwu: The local population of this area (8°00 andOlusi (2000). Two snips, one each from the right and8° 30 E and 6° 58 and 7° 25 N) practice peasantleft iliac crest were taken from each individual with theagriculture, fishing and hunting are secondaryaid of a 2 mm bite corneoscleral punch (E-2802, Holtoccupations. With numerous breeding sites on theStorz, Germany). Each snip was incubated in a well ofOkpokwu river system that drain these villages andmicrotitre plate containing normal saline. The platesoutdoor activities performed by the population, theywere then examined within 30 min to one hour byare continually exposed to bites of the vectors.microscopy for the presence of O. volvulusBuruku and Katsina-Ala: The Etulo community microfilariae (Wentworth, 1988).inhabits twelve villages which are bisected by riverKatsina-Ala, a major tributary of Benue River.RESULTS AND DISCUSSIONMajority of the villages are located along the bank of Out of 31 villages examined, all were found to havethe river with fishing and farming constituting the individuals with LS, whereas 27 (87%) villages weremajor occupation. carrying nodules of onchocercal origin. Out of 2126individuals examined from the Idoma speakingApart from river Katsina-Ala, another perennial rivervillages in Okpokwu LGA, 248 (11.6%) had LS, 105known as Ogaturu drains most of Etulo land. The two(4.9%) had nodules and 35 (1.6 %) had both nodulespredominant rivers are fast flowing and harbour larvaeand LS while 353 (16.6%) had either LS or nodulesand pupae of S. damnosum complex (Nwoke et al.,(Table 1). In 1005 Etulo-speaking individuals, 451998; Gemade and Dipeolu, 1983).(4.5%) had LS, 12 (1.2%) had nodules and 2 (0.2 %)RAMs for diagnosis: Based on the analysis of large had both LS and nodules while 57 (5.6%) had either LSvolumes of epidemiological data on onchocercosis, or nodules (Table 2). The number of cases with LS,depigmentation of skin LS and palpable onchocercal visible or palpable nodules observed in the Okpokwunodules were recommended as rapid assessment area varied significantly (p < 0.05) from that of Etuloprocedures to determine communities eligible for area.treatment with ivermectin. The merits and limitationsWhereas LS in Okpokwu area ranged fromof these methodologies are summarized by Edungbola7.3–28.8%, in Etulo area it ranged from 0.8–14.0%.et al. (1993).Only one village (Ashitenaku) had 14% LS, whereasCommunity: Only adults 18 years and above were all the other Etulo villages had LS below 7.3%. Inexamined for presence of nodules and LS. All persons Okpokwu, the prevalence of onchocercal nodulessampled were engaged in one or more rural occupation ranged from 2.2%–10.9% and in Etulo area it rangedand have resided in the community for at least five from 0.8–3.1% only one village (Ugye) in Etulo hadyears (Gemade, 1993). Communities were visited a nodule prevalence of 3.1%, whereas all other villagesday prior to the fixed date for examination in order to had the prevalence below 2.3%. LS and onchocercalmobilize people for the survey and free treatment. nodules were mostly noticed in individuals within40–69 years of age, highest (48.7%) being in betweenSearch for nodules: For search of nodules, the50–59 years. This same age group accounted forpatients were requested to strip down to the loin. As the20.5% of onchocercal nodules. Correlation analysis toperson stretched his arms above the head, the wholedetermine association between these onchocercalchest region was examined both visually and bymanifestations with age showed significantpalpation. Special attention was given to iliac crestcorrelation (r = 0.45, p < 0.001). The patientsaround knees, ankles, ribs (from and rear), chest wall,complained varying degrees of visual impairment but,shoulders, elbows, wrist and head.only five cases of total blindness were recorded. OneSearch for LS: The search for LS on patients was classical blind case was seen in a 61 years old man inmore specific in location and faster as typical Effa (Okpokwu), who had Leopard skin on both shinsonchocercal depigmentation commonly occurs on and a nodule on the knee. The Etulo area on the otherlower limb of adults above 30 years. Patients were hand had four cases of blindness (two in Ashitenaku,asked to pull up trousers and/or wrappers to the thigh one each in Oglazi and Agbou respectively).region.Skin snip examination in the Etulo area showed 536Skin snip examination: Skin snip parasitological (53.3%) persons were positive for O. volvulusprocedure for identification of microfilariae of O. microfilariae. The prevalence by villages varied with