Report of OCP activities and the entomological results in the Ouémé basin (1978-1998)

LJctr t ..1 I lt lral: REPORT OF OGP ACTIVITIES AND THE ENTOMOLOGICAL RESULTS IN THE OUEME BASIN (1978-1998) Ouagadougou, June 1999 Bv: SamuelA. Sowah Under CONTRACTUAL SERVICE AGREEMEN.T WITH OCP 0cp '1|ctl 0ult rtt COURRI(- 1 '"( Y ircu lr ERA RRIVEE 2I I CONTENTS l.INTRODUCTION 2.DESCRIPTION OF THE OUEME BASIN AREA 3.ENTOMOLOGICAL ACTTVITIES (EVALUATION AND VECTOR CONTROL) 3. 1 . Entomological surveillance. 3.1.1. Breeding points. 3.1 .2. Catching points. 3.1.3. Entomological prospections. 3.2. History on larviciding. 3.2. 1 .Aerial larviciding. 3.2.2. Ground larviciding. 3.2.3. lnsecticides used (lnsecticides rotation) 3.3. Entomological results. 3.3. 1 . Vectors concerned. 3.3.2. Parasites concerned. 3.3.3.Transmission. 4. EPIDEMIOLOGICAL EVALUATIONS 4.1 Epidemiological results before vector control. 4.2. Epidemiological results during vector control 4.3. Latest epidemiological results. 5. IVERMECTIN DISTRIBUTION. 6. SOCIOLOGICAL INVESTIGATIONS. 7. SENSITISATION. 8. DISCUSSIONS. 9. CONCLUSION 3t 1. INTRODUCTION This report is written as a result of contractual service agreement entered into by OCP with the author The aim of this report is to give a consolidated account of OCP activities in the Oueme river basin as well as the results obtained from the beginning of OCP activities to date. The report should covers not only entomological activities but also all aspect of OCP activities such as, epidemiological investigations carried out (with their corresponding results), lvermectin distribution, sociological investigations if any, sensitisation carried out by OCP fietd staff, and any other relevant information available. 2. DESCRIPTION OF THE OUEME BASIN AREA The entire Oueme basin lies in the Republic of Benin. lt stretches from latitude 10 degree North and enters into the Gulf Benin at the coast of the Republic of Benin, in a woody Savannah area known as the Dahomey Gap, where the Savannah type of vegetation stretches from the North of Benin right to the coast. There are two types of climatic conditions, giving two types of seasons, namely the rainy season and the dry season. The rainy season starts in the South around late March and in the North between mid May to mid June. The rainy season ends around mid October or October ending. This ushers in the Hamatan, which marks the beginning of the dry season. The principal tributaries of the Oueme are:- the Alpouro ,the Yerou Maro, the Wewe and the Terou in the North. ln the middle portion are the Odola, the Beffa, and the Adiiro. ln the South are the Okpara and the Zou. Generally, the main river and its tributaries flow mainly in the rainy season, namely from late June to the middle of October, with the peak around the month of September. From late October to the middle of November most of the tributaries stop flowing. The main river, however, continues to flow up to the middle of January. The discharge of the Oueme can reach a maximum of 1400 cubic metres per second. This maximum was recorded in week 36 in 1991 at Atchakpa. On the tributaries the discharge can be more than 500 cubic metres per second. This was recorded at Atcherigbe on the Zou again in 1991 in week 30. See graphs of discharges of the Oueme basin in the annex of this report In the dry season, the entire basin dries up with no flow at all from the North to the area around Zagnanado where minor flow can be observed. Eventually these flows also stop a month or two before the onset of the rainy season. 3. ENTOMOLOGICAL ACTIVITIES (EVALUATION AND VECTOR CONTROL) 3.1 Entomologicalsurveillang€ 3.1.1. Breedinq points 4 Oueme The S. damnosum s.l breeding points on the Oueme itself begins from lat. 9 degrees 40 minutes north, a little bit downstream from Affon catching point. From this breeding point to the confluence of the Yerou Maro, six other important breeding points can be found. Eleven other major breeding points are found from Beterou (lat. 9 degrees 13 minutes North) to the confluence of the Odola (lat. 8 degrees 46 minutes north). Note that these points are identified only in latitudes because of the fact that the Oueme flows virtually from North to South, hence, the latitudes pinpoint to a particular point on the river. From the confluence of the Odola to the Atchakpa breeding point, eleven other major breeding points can be identified. The main complex breeding points on the Oueme are found between Atchakpa catching point and Aguigadji catching point. At this stretch (from lat. 8 degrees north to !at. 7 degree 29 minute north), the breeding points are virtually joined together with very few pools in-between. Below the Atchakpa-Aguigadji stretch apart from the complex breeding point at Tamiedji (lat. 7 degrees 25 minutes north), there are, practically, no natural breeding points On the other hand occasionally man made fish traps can be found here and there. Alpouro Very few breeding points are found on the Alpouro, which are not important for S.damnosum s.l. breeding. Yerou Maro On the Yerou Maro also very few S. damnosum s.l. breeding points are found. The only important breeding point is found near its confluence with the Oueme. Wewe The breeding points on the Wewe are not many and are not important for S. damnosum s.l breeding. Terou There are very few breeding points on the upper stretches of the Terou, where the river flows from North to South. The important breeding sites are located from the confluence of the Aguimo to the confluence of the Terou with the Oueme. Odola One important breeding point on the Odola is situated near its confluence with the Oueme. Other minor breeding points are found upstream but these do not play important role in S. damnosum s.l breeding because of the short duration of flow of this tributary. Beffa The uppermost breeding point on the Beffa is located lat. 8 degrees 48 minutes North. There are no breeding points down to lat. I degrees 39 minutes north. From this 5 point down to the its confluence with the Oueme twelve important breeding points can be found. tt is important to note that S. soubrense Beffa form is named after this river since this specie was first discovered on this river. Adiiro The principal breeding points about fifteen in number, lie between longitudes 2 degrees East and 2 degrees 15 minutes East around latitude 8 degrees 29 minutes North Okpara Among all the tributaries of the Oueme the Okpara is the tributary with the greatest number breeding points, for, at least, about one hundred and eighteen (118) principal breeding points can easily be identified. The majority of these are found between lat. 9 degrees 4 minutes North and !at. 7 degrees 53 minutes North, where the Okpara forms the demarcation line between the Republic of Benin and Nigeria. The rest of the breeding points (about thirty -eight in number) are entirely found in the Republic of Benin. Zou The Zou lies entirely in the Republic of Benin and takes its source around !at. I degrees 27 minutes North, near a village called Pira and enters into the Oueme around lat. 7 degrees near a village called Gongbe. The Zou is considered to be one of the longest tributaries of the Oueme but has relatively fewer breeding points compared with the Okpara, the other long tributary. The principal breeding points, twenty-one in number, are situated between latitudes 7 degrees 35 minutes North andT degrees 20 minutes North. Downstream from the breeding point on !at. 7 degrees 20 minutes North, no more natural breeding points occur, except one or two man made fish traps which constitute artificia! breeding points. The river itself flows very Iiftle at this stretch with the presence of lot of green algae. 3J-2Gatshlns pelnE 3.1.2.1 Oueme The total number of catching points on the Oueme itself along the years had been six. These are; Beterou, M'Betekoukou, Atchakpa, Affon, Aguigadji, and Zagnanado, in order creation Beterou 1819 The first catch was made at this point by the Sub-sector of Natitingou October 1976. The point was then passed on to the Parakou Sub-sector after the creation of the latter in 1978. The point has therefore been under the Parakou Sub-sector to date. Beterou, the first catching point on the Oueme, is regularly used as monitoring point to date. Atchakpa 2703 Atchakpa was created in 1978 with the creation of the Sub-sector of Parakou and also coming into being of the Southern Extension. The first catch was made at Atchakpa in [[re nrcnth of Decem\Br 1978, and is being used regularly to date. 6M'Betekoukou M'Betekoukou has a similar history like Atchakpa. lt was created in 1978 and the first catch was made in the month of November 1978, and is still being used as a monitoring point to date. This point was first under the Parakou Sub-sector but passed on to the Bohicon Sub-sector in 1982. Atfon 2710 Affon was created in1979 and the first catch was made in January 1979. This point was used regularly until April 1986. Catching was stopped because of the low catches registered at this point and also because of economic reasons. ln 1987 OCP had to take strong economic measures to stay within the budget, because of lack funds. There was therefore reduction in VCU (Vector Control Unit) activities. This reduction affected certain number of catching points visited at that time. Affon was one of them. Aquioadii 2711 Aguigadjiwas created in 1982 and the first catch was made in September 1982. The point was first under Parakou Sub-sector but later on transferred to the Bohicon Sub-sector in 1982. Since its creation Aguigadji has been a regular catching point to date. Zaonanado 3002 This point was created in 1982 with the creation of the Bohicon Sub-sector. The point was regularly used from September 1982 until September 1987, because of similar reasons already mentioned under Affon. 3.1.2.2 Terou Wari Maro 2705 The only catching point on the Terou was created in 1978 and first catch was made in November same year, and has been used regularly monitoring point to date. 3.1.2.3 Adiiro Banon 2707 Like the Wari Maro is the only catching point on the Adjiro was created in 1978. The first catch was made in November in the same year and has been used regularly to date. 3.1.2.4Betta 2701 Vossa was created in 1978 with the first catching made in November and is still a monitoring point to date. 3.1.2.5 Okpara Binassi 1918 Created in June 1978 and used regularly till 1987 Kaboua 2702 Kaboua was created in J97fl.,The first catch was made jn November same year and has been used regularly to da{e. 7The point was created in 1979. The first catch was made in June 1978 and is still being used as monitoring point to date Okeo 2713 Bassa 27Oo The point was created in 1978 and was under the Sub-sector transferred to the Bohicon Sub-sector in 1982 after the creation of th Okeo was created in 1982 with its first catch in June the same year It was used as a regular monitoring point until 1990 3.1.2.6 Zou The Zou has three catching points, namely, Atcherigbe, Zoudji and Cove Atcheriqbe 2T09 of Parakou, but is Sub-sector. The first catch was made in November 1978 and has since been a regular catching point to date Cove 3003 Cove was created in 1982 and was under the Bohicon Sub-sector. The first catch was made in August 1982.|t was a regular catching point until October 1987 when catches were stopped for the same reasons given under Affon. Zoudii 3004 Zoudji was created in 1982 and was a regular catching point for only two years because it's low fly count. The first catch was made in August 1982 and 1984 catches were drastically reduced. After this year no catches were made until 1989 when only three months catches were made, and a month in 1995. 3.1.2.7 Yerou Maro Barerou 2714 The first catch made at Barerou in 1982 and has been used regularly to date. 3.1.3 Entomoloqical prospections Several entomotogical helicopter prospections were carried out on the Oueme and its tributaries for various reasons. Among these were the following: -1. lnvestigations into suspected treatment failure. 2.To investigate the problem of re-invasion of the Oueme valley by S. soubrense Beffa form, from neighbouring Nigerian rivers. 3. For, purely research reasons. 4. For, Operational reasons. 3.2 Historv larvicidinq 3.2.1 Aerial laryicidjog Aerial larviciding began in the Oueme basin at Lower Oueme in week 12 1987. This continued untit week 18, then treatment was suspended due to lack of flow. Teknar was the larvicide used. Treatment was resumed in week 36 and continued for six cycles, namely, from week 36 to week 41. The larvicide used this time was Temephos (Abate). 8 It is important to note that the period of commencement of treatment was in the dry season. The aim of this was to eliminate the S. damnosum s.l population at their dry season foci before the onset of the rainy season. ln so doing, economy could be made in the rainy season by treating shorter stretch of the river or suspend treatment for good results, namely, absence of flies. This theory was however, dashed because of invasion or contamination of the Oueme basin by S. soubrense Beffa form from neighbouring rivers in Nigeria. Since the first treatment (larviciding) on the Oueme and tributaries in 1987, aerial operations have not been stopped in the Oueme basin to date. Aerial operations are suspended only in the dry season when the entire basin dries up (see section 2 paragraph 7 of this report). The period for a minimum treatment in the Oueme basin for a given year is between weeks 1 to 8. The period for maximum treatment is between weeks 26 to 45, with the peak, occurring, between, weeks 36 to 40. ' These treatment cycles correspond to the pattern of discharge of the Oueme and it's tributaries during a given year as already mentioned. It is important to note that susceptibility to Temephos (Abate) in the Oueme basin was normal from 1983 to 1993. Resistance uvas detected on the lower Oueme, at the stretch OU 7OO, around Agonlin Kpahou, OU 600 around Atchakpa, on the Okpara at OU 710 and 720, and on the Upper Oueme, at OU 104 around Affon in 1993. ,3.2.2 G roun 4 la nri ci d Ln_gt Ground larviciding is not used in the Oueme basin as the main method of vector control but as support to aerial larviciding in the case of treatment failure due to bad passage of larvicide or when a breeding site is missed after the passage of an aircraft. It is also used in the dry season on certain isolated breeding points to minimise treatment cost of aeria! larviciding. At very low discharge in the dry season when aerial larviciding is difficult to carry out ground larviciding is again employed. This is usually between weeks 1 to week 8, on the tributaries. Ground larviciding is carried out by the various Sub-sectors of ex Parakou Sector, depending on the location of the points to bre treated. 3.2.3 lnsecticides used (insecticides rotation) From 1987 to date all the insecticides employed by the programme (Abate, Bt., both Vectobac and Teknar, Phoxime, Chlorophoxime, Pyraclofos, Permethrine, Carbosulfan and Etofenprox) are being used on rotational basis in the Oueme basin. The reasons for the rotation of insecliicides are as follows: - 1. To prevent the occurrence of resistance, which may occur if only one insecticide is used, as this occurred with Abate in the early stages of the Programme. !n order to avoid this, the consecutive use of insecticides belonging to the same chemica! compound is discouraged to prevent cross-resistance. 2. The rotation is atso carried out for the cost effectiveness of treatment, e.g. using Bt. at very high discharge will require a huge volume to be used, which will also require a lot of ferry time for an aircraft for loading. On the other hand an insecticide like Permethrine which is highly toxic requires very small volume at very high discharge, thus a small amount can cover a lot of river stretch to be treated. ) t 93. Rotation of insecticide is carried out accorrJing to the toxicity of the insecticide at different discharges on non-target organisms. For example Bt. which has a very low toxicity on non- target oiganisms is used at low discharges, namely from 1 cubic per second to about 35 crbic metres per seconds. While Permethrine, which is highly toxic, is only used when the discharge is higher than 70 cubic metres per second and cannot be used for more than six treatment cycles in given yeat. The same is applied to Carbosulfan. Pyraclofos is used at a discharge of 15 cubic metres per second onwards, and this applies to Etofenprox also' On the other hand, insecticide like Abate, Phoxime, and Chlorophoxime, which have relatively low toxicity, can be used even at low discharge. 4. Finally rotation is carried out according to the carry of the insecticide. Bt., for example, which has very low carry, will require a lot of treatment point at higher discharges. This therefore renders it unsuitabte for high discharge treatment because the volume of product to be wi!! not be cost effective as pointed out earlier on. However insecticide like Abate, which have a very good carry couple with its low toxicity on non-target organisms can be used at almost any discharge. Pyraclofos is another insecticide, which has a very good carry but because of its toxicity as indicated earlier on, it is used from 15 cubic metres per second upwards. The practical aspect of the rotation of insecticide can be seen on the table of treatment of the Oueme basin in the annex of this report. ln the Oueme basin, resistance to Temephos had been intermediary in 1981, but in 1993, resistance was detected at the Lower Oueme area around Agonlin Kpahou (OU 700), Atchakpa (OU 600), the Upper Oueme around Affon (OU104), and the Upper Okpara around Bassa (OU 710 and OU 720). The susceptibility to Temephos became normal in 1998. See graph on "Resistance to Temephos Zone East.' 3.3 Entomoloqical results 3.3.1 The vectors involved To determine the vectors involved in the Oueme basin, adult flies are caught by vector collectors as described by Walsh et al (1978) are separated into different groups, through their wing tuft examination using Kurtat method. These groups are classified as 01, 02, 03, 04, and 05. The 01 groups are the ones with all the individual hairs of the wing tuft pale. The 02 groups are the ones with the nrajority of individual hairs of the wing tuft pale, with the presence of some few dark hairs (less than 50% of the tota! numbers of the wing tuft hairs). These two groups are considererd to belong to the savannah group of species, namely, S. damnosum s.s and S. sirbanum. The 03 groups are the ones with 50% pale hairs and 50% dark hairs. These can be savannah species (S. damnosum s.s) or S. squamosum or can even be S. soubrense. These are however rare in the Oueme basin. The 04 group are those with the majority of the hairs on the wing tuft dark. The 05 groups are those with 100% dark wing tuft hairs. These two groups are the forest species S. santipauli or S. soubrense [although it has been pointed out that some members of adult flies morphologically looking S. soubrense Beffa form have pale wing tuft (Garms 1978 and Meredith et al 1983.), but these have disappeared after the 1983 drought ( Cheke et al 1e87)I From available data for both adult population and larval population, the dominant species on the tributaries of the Oueme is S. damnosum s.s. On the other hand, on the Oueme South of Beterou catching point ther dominant species during the major part of the i-r I10 rainy season is S. soubrense Beffa form. See graphs on MBR (Monthly Biting Rate) on seasonal variation of S. soubrense Beffa form at Atchakpa and M'Betekoukou catching points. These two graphs are obtained from data from 1980 to 1998. No S. santipauli and S. vahense have ever been found in the Oueme basin, either by cytotaxonomy or by adult morphological examinations 3.3.2. The parasite involved Since the creation of the DNA laboratory, it has been shown that the majority of the parasites transmitted in the Oueme basin are the Savannah strains. Occasionally some forest strains are also transmitted. lt is important to note that these Savannah strains are transmitted by both the Savannah flies (S. damnosum s.s. and S. sirbanum), and the forest flies, namely, (S. soubrense Beffa form) as shown later on. 3.3.3 Transmission From the tables of the Annual Transmission Potential (ATP) and the graphs of ATP for both the Oueme and it's tributaries, the pre-control data showed that transmission was very high on both the Oueme as well as it's tributaries. The ATP values for all species combined were over 6000 at M'Betekoukou (Oueme), and Atcherigbe (Zou). On the Okpara at Kaboua, the ATP was slightly over 8000. The other points like Atchakpa, Beterou, and Aguigadji on the Oueme had pre- control ATP of less than 4000. On the other points of the tributaries, like Wari Maro (Terou), and Vossa (Beffa) the pre-controlATP was around 5000. The rest of the points like Banon (Adjiro), Zagnanado (Oueme), Affon (Oueme), and Barerou (Yerou Maro) had pre-controlATP of less than 1000. Before vector control operations started, there was a severe drought in 1983, and the situation returned to normal after 1985. This drought affected both the pre-controlATP and ABR significantly, as shown on the graphs of ATPs and ABRs by the first arrow on these graphs. The post control transmission is from 1987 when the first aerial Iarviciding began. The drought mentioned below greatly helped to bring down transmission from pre-control data to around an ATP of about 1000 as early as 1986, a year before aerial larviciding. The only point which had ATP of more than 1000 was M'Betekoukou, with ATP of more than 2000 in 1992. From 1994, seven years after the first larviciding, the ATPs on all the points in the Oueme basin, except at Kaboua on the Okpara, had fallen below 1000. These results are exceptionally good, considering the time involved. lt is however important to note that apart from the drought factor, large-scale ivermectin distribution began in the Oueme basin in 1990. On the Oueme itself greater proportion of transmission is by S. soubrense Beffa form, as shown by histograms of ATPs at the following catching points, M'Betekoukou, Aguigadji, and Atchakpa. However, on the Upper Oueme at Beterou transmission is mainly by Savannah species S. d3rtlnqsum s.s and S. sirbanum (histogram ATP Beterou). t11 On the northern tributaries like the Terou and Yerou Maro, again S. damnosum s.s and S. sirbanum are the major transmitters (ATP histograms of Wari Maro and Barerou catching points show this clearly).t-' As one goes down south, transmission by S. soubrense Beffa form becomes important on the tributaries like Beffa, Okpara, and the Zou, (See histograms of ATPs for Vossa, Kaboua, and Atcherigbe respectively. 4. EPTDEMIOLOGICAL EVALUATIONS 4.1 Eoidem Iooical results before control. The summary of the epidemiological data, for the Oueme basin, can be found in the annex of this report, in a table, with the title "SUMMARY OF EPIDEMIOLOGICAL DATA". 4.1.1 . Oueme The pre-control data for the epidemiological survey showed villages with very high Prevalence (Prev.). The notable ones are villages on the Oueme itself, south of Beterou catching point. The Community Microfilarial Load (CMFL) was also quite high in these villages, e.9., 1 . A village like Abgagoule, code 392, had Prev. ol70.2o/o in March 1979 (8 years before vector control), with CMFL of 16.74 mf/s, and Prev. blind of 0.6%- 2. Agonlin Kpahou, code 5078, had Prev. of 72.2% in December 1989 (barely 2 years after aerial Iarviciding), with CMFL of 13.97 mf/s, no blind case recorded. 3. Atchakpa, code 3881, had Prev. ol68.20/o in May 1978 (9 years before aerial larviciding), with CMFL of 23.51mf/s, and Prev. blind of 3.5%. 4. M'Betekoukou, code 399, had Prev. of 78.0o/o in April 1979 (8 years before aerial larviciding), CMFL of 19.59 mf/s, and Prev. blind of 1.7%. 5. Koko, code 205, had Prev. ot64.4% in May 1978 (9 years before aerial larviciding), with CMFL of 36.79 mf/s, and Prev. blind of 2.3%. 6. ldadjo, code 390, had Prev. of 73.4 % in March 1979 (8 years before aerial larviciding), with CMFL of 28.89 mf/s, and Prev. blind of 1.3%. 7. Banicri, code 315, had Prev. of 69.3% in June 1977 (10 years before aerial larviciding), with CMFL of 24.80 mf/s, and Prev. blind of O.3Yo. 8. Aguigadji, code 408/5083, had Prev. of 81.9% in April 1979 (8 years before aerial larviciding), with CMFL of 33.31 mf/s, and Prev. blind of 3.7o/o. g. Wewe, code 316, had Prev. of 61.9% in June 1977 (10 years before aerial larviciding), with CMFL of 12.72 mf/s, and Prev. blind of 0.3%. 4.1.2. Zou ln the Zou valley, epidemiological surveys had been carried out at least once in 14 villages. Out of these four villages will be used for this report. These four villages are chosen because of their high pre-control prevalence. 12 1. Ferme Agbodjime, code 5076, had Prev. 68.8% in December 1989 (barely 2years after aerial larviciding), with CMFL of 17.49 mf/s, with no record on blind case. 2. Konkondii, code 395, had Prev. ot72.4% in March 1979 (8 years before aerial larviciding), with CMFL of 24.56 mf/s, and Prev. blind of 2.3o/o. 3. Zouto, code 400, had Prev. of 69.5% in April 1979 (8 years before aerial larviciding), with CMFL of 25.82 mf/s and Prev. blind of 3.5o/o. Avideme, code 5249, had Prev. of 66.40/o in October 1990 (barely 3 years after aerial larviciding), with CMFL of 20.16 mf/s. No blind case recorded. 4.1.3. Terou On the Terou - Oueme basin, surveys had been carried out at least once in seven villages. The pre-control Prev. for these seven villages has a range ol 59.7o/o to 82.6%. Except for two of these villages, namely, lgbomakoro, code 386, and Sawoundi, code 387, the rest had been visited only once. These villages therefore will be used for illustrative purposes. '1. lgbomakoro had Prev. of 78.4o/o when it was first visited in May 1978 (9 years before aerial larviciding), with CMFL of 31.89 mf/s, and Prev. blind of O.7o/o. 2. Sawoundi had Prev . of 59.7o/o in May 1978 (9 years before aerial larviciding), with CMFL of 14.72, and Prev blind of 0.6%. 4.1.4 Kouffo Pre-control epidemiological surveys had been carried out in eight villages in the Kouffo va!!ey. The pre-control Prev. was not very high compared to that of the Oueme or the Terou. Except for the village Kogbetohoue, code 401, where the pre-control Prev. was 60.40/o, in April 1979, the rest of the villages had Prev. of less than 50%. The range is 6.7% to 46.50/o. See table on the summary of epidemiological data on Kouffo further details. 4.1.5 Okpara For pre-control data of epidemiological surveys two villages are chosen for illustrative purposes, and these are: - 1. Kaboua, code 275,had Prev. of 69.6% in May 1978 (9 years before aerial larviciding), CMFL of 17.52 mf/s and a Prev. blind of 0.3%. 2. Woria, code 396, had Prev. of 70.4o/o in April 1979 (8 years before aerial larviciding), with CMFL of 23.91 mf/s, and Prev. blind of 1.5%. 4.2 Epidemioloqical results durinq Vector control. The epidemiological results during vector control were distorted by large scale ivermectin distribution, which started, in the Oueme basin in most places, in 1990. The evaluations therefore carrie(orrt in 1994 gave very low Prev., barely 7 years after vector control began. 13 The following villages illustrate this distortion clearly 1. As already shown the pre-control Prev. for M'Betekoukou was 78.0% with CMFL of 19.59 mf/s (in 1979). In February 1987, the Prev. was unchanged (78.8%). !n 1994 during the month of December the Prev. fell as low as 18.1o/o with CMFL of 0.41 mf/s 2. Another village is Zoudji, code 5396, had a Prev. of 46.40/o in December 1992, with CMFL of 4.75 mf/s. ln November 1995, the Prev. fell to 14.6% with CMFL of only 0.44 mf/s. 3. A third example is the village Fonkpodji, code 394, had Prev. of 63.1% in March 1979,with CMFL of 17 .45 mf/s.. Two years after ivermectin distribution, namely in 1992, and barely five years after vector contro! started, the Prev. fell to 50.8%, with CMFL of 8.92 mf/s, and three years later, namely, in 1995, the Prev. fell to 22.60/o with CMFL of only 0.88 mf/s. These three example, therefore, makes further epidemiological evaluation in the Oueme basin meaningless, since the ivermectin intake by the villagers affect the real trend of the effect of vector control, hence the absence of continued epidemiological evaluations on many villages in the Oueme basin. 4.3 Latest Epidemiolooical results 4.3.1 Oueme On the Oueme itself, the latest epidemiological evaluations had been carried out in the following villages. 1 . Atchakpa, code 381/5880, which had pre-control prevalence (Prev.) ol72.2Yo, as already mentioned, now has Prev. ol 3.8o/o in April 1999, with CMFL of only 0.13 mf/s. 2. ldadjo, in February 1998 now has Prev. of 17.7o/o, with CMFL of only 0.55 mf/s, compared to73.4o/o as already mentioned. 3. Koko, in February 1998 now has Prev. of 9.8% compared to 64.40/o in May 1978. 4. Tosso, in April 1999, now has Prev. of 5.4o/o compared to 57 .3% in October 1989. 5. Wewe, in April 1999 now has Prev. of only 0.60/o compared to 61 .9% in June 1977 . 4.3.2 Tributaries of the Oueme Latest results of the villages on the tributaries of the Oueme, like, Okpara, Zou, Terou, and the Kouffo, showed that the prevalence has fallen so low. ln some areas it is less than 10%, with CMFL of less than 1 mf/s. (For further details, see tables on epidemiological data). 6. IVERMECTIN DISTRIBUTION. Large-scale ivermectin distribution began in the Oueme basin, Zone 3, in 1990, where 11 villages were covered. In 1991 the Oueme Zone area was again visited, this time covering 36 villages. 14 ln 1g92 the Lower and the Upper Okpara, as well as the Middle Oueme were visited covering again 36 villages, also on the Agbado, the middle Zou (Zone 4), where 104 villages were covered. ln 1993 the areas, where large-scale ivermectin distribution took place were Kouffo, Oueme and Okpara, where 415 villages were covered. !n the same year (1993) the Oueme and the Zou were visited, covering 347 villages, and on the Kouffo 1, 87 villages were covered. !n 1994 the Agbado, the Middle Zou had large-scale ivermectin distribution which covered 14 villages. !n 1995, Zones 3 & 4 were visited again covering 349 villages. ln the same year, the Upper and the Middle Okpara (Zone 5) were visited, where 312 villages were covered. ln the same year, Terou (Zone 6) was also visited covering 305 villages. It should be noted here that, from 1990 to end of 1996, the national mobile teams, headed by the national Co-ordinator carried out large-scale ivermectin distributions, involving the local district health units. The details of al! large-scale ivermectin distribution, distributed this way, can be found in the table provided in the annex of this report. !n January 1997, the village communities were trained to carry out large-scale ivermectin distribution themselves, this had therefore been the case since then. 6. SOCIOLOGICAL INVESTIGATIONS. According PET Unit, no sociological investigation has been carried in the Oueme basin to date. 7. SENSITISATION. From the beginning of OCP activities in Oueme basin, for that matter in the whole Programme area, al! activities were carried by the OCP staff of the Sectors and the then Epi. Unit without involving either the village communities or the local health authorities. There was complete lack of information between OCP and the Villagers as well as the local authorities. This situation created the grounds for misinformation concerning OCP activities in the areas of: - . Cessation of OCP activities at certain areas due to good results, thus bringing about the return of the Simulium flies. o Apathy shown by both the villagers and the local health authorities towards OCP activities such as ground larviciding and catching of flies. . Lack of interest shown by both villagers and local authorities concerning OCP properties, like Kerosene for the helicopters, and insecticide for aerial larviciding at the OCP depots in the fields. . Low turn up by the villagers for OCP activities such as epidemiological evaluations and later for ivermectin d istributions. . Misconceptions concerning the intake of the ivermectin tablets. o Misconception on the mode of transmission of Onchocerciasis by the general public. ln 1987, it therefore became important for OCP to carry out intensive campaign for IEC 15 (rnformation - Education - communication) toiectrfy the misinformation created by lack of communication between ocp ..0 ,n"t"ilJ prurit. iiir ui"rght about need to sensitise ;#ilil;-' ocP fflli'::*::"J"i1*^roy-l-"y-:,ote with minimum or no extra cost rhis was made possible by using tne ,,'io'l'S""too 'tnO d'[-t"'tott staff' during their weekly routine circuits on prospection or.ra.Jri"n".rs, and .;t.fi;;.tivities, to carry out the IEC' sensitisation is carried ort *iiioJi"rJio-'i""iilip"t'*t' for the principal method used is direct ro.i".i*itn tn" ro..r .offirniti". and tatring to tngr. on matters concernrng a* aspect of the Programme's.activif;;;;ith affect tn" "oi.'uni$ in question' The following are the topics used depenoing on the to"'nity in question or the target population. o rn areas where there is cessation of rarviciding activities, the communities are informed about tf,e eminenii"trrn of the r;;i;tiih; Simulium flies)' Telling them about the non- ineffectiveness of the return"o ir',lr.. nrso informing and explaining tothemaboutthegoodresultsofvectorcontrolintheirafea. o ln areas where vector.oni.r is still going ot, tn" communities are informed about importance of the ;ilt"#"t "Jtruities in their area- Explaining to them consequences of now trre iiie,,,ption of tnese activities in their area will adversety affect them. r. "t'"i";iJs tne P;;;;e is for them and should ccmitler the progra.r"'J p[p"rt,."t (lke Kliosene and insecticides in the drpo, ar treirs ano snou'iil" rlox"a'anei ano-frotect them from theft and bush . Ll"i;r"ation institutions, both schoor authorities and students or pupils' are lectured on thc various asp""t of the pr"gr"*r*is activities- Also on the biology of the life cycle of the ;;fi, ;d the'mode of transrnission of the onchocerca parasites to man through the vector-etc' . uri, rake nlace. the communities are o ln areas where epia"miorogical evaluatro;'t will t k p ' cducated on the n""o tl-1"';;';ih-[he investigators' and also the need to assembre ror tke-urrrii-,J,i. "i g," appoinieJpra-ce on the right date and at the . "ilX,'Xl"l where large-scale ivermectin distribution is going, the communities are informed about tt" neJJ to tare tne pilr, ano ney are-also sensitised about the fact that ivermectin i. ."t" to iake and is given tiee of .charoe. This method was used at a time when ivermectin was Oistr'iOui"O UV nationalhobile teams' The communities themseM;;;;eistribute iveimectin, under what is known as cDTl tcommunity=oirectedTreatmentoflvermectin). ln the oueme basin, from 1gg7 to date many of these se-nsitisation sessions have been carried out by the sector.Jin" rrrious suo-sector staff, and these are still going on' for it isano:H:'#fi3ffi;. that these sensitisation sessions have {,one a lons to improve the pubric .."r"iion between ocp and the vi[age communities in the oueme basin as well as puOiic relation with the local authorities' for: -i. The local authorities as well ,itn" local village communities' depending on the locations of the depots, no* trr" care of and guard the depots in question' 2. The above co-operations of t'n" L.rr communities ano autirorities with ocP had gone a long way to reduce the incide.;;i theft of OCF prcducts at the various depots' Thus' 3 ffI::r'J:1"j",?JllXit$Ls*l1o^cp.tiuties in the fierd bv the pub[c in senerar, especiallyln "r"". ot ""ssation oi ocp activities due to good results' 4.Thepublic,-.pt,withlessdifficultythereturnoftheSimuliumfliesthanbefore. 16 5. Village communities now willingly take the ivermectin tablets without difficulty. Under CDT!, they now distributing the drug themselves. 6. National epidemiological evaluation teams can now conduct evaluation in the villages, either with the patch test method or the skin snip method with less difficulty. 7. There is a better co-operation between OCP and the local communi$ health authorities 8. DISCSSIONS. 8.1. Fly catching data from 1980 to 1998 showed a particular paftern of seasonal variation fly species population. The seasonal variation is between S. damnosum s.s and S. sirbanum on one hand and S. soubrense Beffa form on the other hand. From the analysis of data from 1980 to 1998, it is clearly shown that S. soubrense Beffa form becomes the major component of the fly population in the Oueme basin during the rainy season and completely absent during the dry season. This is true only at the stronghold of S. soubrense Beffa form areas (the Oueme valley from Atchakpa to Aguigadji, and on the Okpara from Kaboua to the confluence with the Oueme). See radar graphs on seasona! variation of S. soubrense Beffa form at Atchakpa and M'Betekoukou. 8.2. From 1987 (the first year of aerial larviciding) to date, vector control operations have produced very good results, as can be seen in the various ATP graphs in the annex of this report. ln some places the ATP had rapidly fallen so !ow. The ATP of less than 100 is recorded in some places, only after 9 years of aerial larviciding. The drop in ATPs in the Oueme basin is very rapid compared to what normally occurs during vector control. This rapid drop in ATPs can be aftributed to three factors. The first factor, being the severe drought, which occurred in the sub-region in 1983. From the graphs of ATPs on the Oueme and the tributaries, it is shown that after the drought, and even four years before aerial larviciding, the ATPs had started dropping already. These ATPs did not come up to their original values after the end of the drought, which was marked with the beginning of the 1985 rainy season. ln fact, the ATPs remained low till the beginning of aeria! larviciding in 1987. The second factor being, the beginning of large-scale ivermectin distribution in the Oueme basin in 1990. lt has been shown the intake of ivermectin by the human population in an area can reduces the mean microfilariae Ioad (m0 in the skin of treated person by 96%-99%. After 12 month, the subsequent mf-repopulation in the skin is about 40% of its original level (Remme J. et al 1990). This means that, during the 12 months after treatment with ivermectin, the Simulium fly can ingest0o/o4Oo/o of microfilariae from the skin when it bites a treated person. The reduction of microfilariae load in the human population will therefore result in the reduction of infective larvae in the fly's head (L3H). The ATP calculation is based on the presence of infective larvae (L3H) in the head of the fly. The ATP will therefore be low if few L3Hs are obtained. The third factor is vector control itself. From the graph of the Annual Biting Rate (ABR), it can be seen that, although the basin is contaminated each year by S. sou rense Beffa form flies from Nigeria, there \q progressive downward trend. This means, there is gradual reduction in fly popula(on each year, indicating good control strategy. 8.3. It is important also to comqlqnt on the vectorial role of the S. soubrense Beffa form in the Oueme basin. As already mentioned earlier on in this report, S. soubrense Beffa form is the major transmitter in the Oueme vatley itself. Transmission S. soubrense Beffa form is in the rainy season only (See histogrq4s already mentioned). There is no transmission in the dry season like S. squamos\+S (q,eq in perennial rivers (Cheke et al 1991). On the other hand, 17 it has been shown that S. yahense does not show any major seasonal variation in transmission (Cheke et al '1992). This therefore, means that if S. soubrense Beffa form were not to be a contaminant of the Oueme, the ATPs would have been lower than what they actually are. This can be seen in the parts of the basin, which are not the strongholds of S. soubrense Beffa form. lf one compares the ATPs from the Beffa strongholds with the ATPs from other parts of the basin, it can be seen that, the values of ATPs in the strongholds are 3 to 4 times higher. 8.4 lt is important to note that S. soubrense Beffa form spreads very little from their points of arrival in the Oueme basin, namely, the Lower Okpara and the Lower Oueme (their strongholds). They are therefore rarely found to the west or to the north of the strongholds. Although it has been shown in the laboratory that S. soubrense Beffa form can fly long distances (Cooter 1983), they seem to restrict themselves to the strongholds in the Oueme basin. 8.5 The pre-control epidemiological data showed high prevalence values for the Oueme basin, around the strongholds for S. soubrense Beffa form (68%-80%). On the other hand prevalence blind values for the same areas were quite low (1 .70o/o -3.5%). This show that, although S. soubrense Beffa form, are good transmitters of the Savannah strain of the Onchocerca parasite (DNA lab results), the transmission does not result in the blinding type of Onchocerciasis. This situation is worth looking into for clarification. The question to be answered is this. " ls the Savannah strain of Onchocerca parasite transmitted by S. soubrense Beffa form are different from other blinding Savannah strains found elsewhere?' 9. CONCLUSION. The latest entomological and the epidemiological results show that the Onchocerciasis situation in the Oueme basin is good. There is progressive regression of Onchocerciasis by way of transmission by the fly (ATPs) and the prevalence in the human population. This means the control strategy in use (combination of vector control and large-scale ivermectin distribution) is a good one. Especially, if one takes into consideration the duration of vector control in the Oueme basin. The strategy is worth considering if one has in mind of rapid Onchocerciasis contro! in isolated foci. The data available show that S. soubrense Beffa form is a good and important transmitter during the rainy season, but not a good transmitter if present in the dry season This means if the contamination phenomenon by S. soubrense Beffa form is checked, the Onchocerciasis situation in the Oueme basin would have been better. The composition of the fly population in the Oueme valley varies according to the season. ln the rainy season, S. soubrense Beffa form constitute the majority of the fly population on the Oueme itself. ln the dry season and late rainy season the population composition changes to S. damnosum s.s and S. sirbanum 18 ACKNOWLEDGEMENTS My sincere thanks go to the Programme Director of OCP and the acting Chief of Vector Control Unit (VCU) for giving me the singular honour by inviting me to come to Ouagadougou to write this report. The writing of this report should not have been possible without the help of all the VCU staff in both Ouagadougou and in the field. This is to say a big thank you to them all. My special thanks go to Mr. AKE Flavien for the vital tips provided in the use of the computer in the writing of this report, in the making of the various graphs and the maps of this report. Many thanks to Mr S. N'GADJAGA for all the computer installations which made it easier for me to write this report. ! wil! also like to express my sincere gratitude to the PET Unit for the epidemiological information provided as well as the data on the Iarge-scale ivermectin distribution in the Oueme basin. 19 REFERENCES Cheke R. A., Garms R., Ouedraogo J., Some A., Sowah S., (1978). The Beffa form of Simulium soubrense of S. damnosum complex in Togo and Benin. Medical and Veterinary Entomology (1987) 1. 29-35. Cheke R. A., Sowah S., Avissey H. S. K., Fiasorgbor G. K., and Garms R. (1991) Seasonal variation in Onchocerciasis transmission by S. squamosum at perennial breeding sites in Togo. Transactions of the Royal Society of Tropical Medicine and Hygiene (1991) 85. Cheke R. A., Avissey H. S. K., Sowah S., Walsh J. F., and Garms R. The vectorial Efficiency of Simulium vahense populations in South-Eastern Ghana. (ln press). Cooter R. J. (1983). Studies on the flight of the black flies (Diptera: Simuliidae). ll. Flight performance of three cytospecies in the complex of Simulium damnosum. Theobald Bulleti n of Entomolog ical Research. 7 3. 27 5-288. Garms R. (1978). Use of morphologica! characters in the study of Simulium damnosum s.!. population in West Africa. Tropenmedizin and Parasitologie (1978) 29. 483- 491. Garms R., Cheke R. A., Vajime C. G., and Sowah S. (1982). The occurrence and movement of different members of Simulium damnosum complex in Togo and Benin. Z. angew Zool (1982). 69.219-236. Garms R., Cheke R. A. (1985). lnfection with Onchocerca volovulus in different members of the Simulium damnosum complex in Togo and Benin. Z. angew Zool (1985) 72.479495. Meredith S. E. O., Cheke R. A., and Garms R. (1983). Variation and distribution of forms of Simulium soubrense and Simulium santipauli in West Africa. Annals of Tropical Medicine and Parasitology (1983) 77.627-640. Remme J., Desole G., Dadzie K.Y., Alley E. S., Baker R. H., Habbema J. D., Plaisier A. P., and van Oortimarssen G. J. (1990). Large-scale ivermectin distribution and its epidemiological consequences. (Review) Acta Leidensia. 5991-2): 177-91, 1990. Sowah S. A., Kassambara M., Avissey H. K. S., Amadou A., and Gbaguidi P. (1992) Seasonal Variation of S. soubrenseBeffa form population in the Oueme valley and its vectorial efficiency in 1991 and 1992. (Unpublished). Vajime C., and Quillevere (1978). The distribution of the Simulium damru$um complex in West Africa with partihrlar reference to the Onchocerciasis ControlProgramme area. Tropenmedizin and Parasitologie (1978) 29. 473-482). 20 ANNEXES Discharge o \Ioo O)oo (rloo Noo Joo (,oo 5oo Ia o 0,a GIo o 0l Eo o o = oor t0 1 3 5 7 o 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 ll(o co@(oro Discharge o J CDoo 5oo N)oo Jooo @oo O)oo 5oo Noo tr, 6' o !,d oo !) o q,rE 0, Eo oxo 1 3 5 7 I 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 il(o(o NA hargeDisc Noo(rlooo(no N(rl oo o o o =!l -tGI oo !l o o oN o,q, {ooro 1 3 5 7 I 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 lt@@(,t@ Discharge o rNG)5(,lO,oooooooooooo o a o ql GI oo !t el o =.GI ETo €oor th 1 3 5 7 I 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 il(o (o N)A s (rl+(Jls,(Jt CL_95 (mg/l) N N(rl G) Jt'_\P(Jloo Ipql o 9. =o N o - J o Ino !-+ 7 @rosL 1a-o F}o {oor+o CLo CN o - J 9. = It F} @r g, E {o 3 oE' - ) oa CL o I(ooo !)r d(o(0 @ (o @ ,o (o @ (o @ N) (o @(r) J @@5 (o @(rr (o @ o) J(0 @{ J(o @@ !, =r =(o(Dr@o(oo (o(oo (o(o J (o(o l\) (o(o G' (0(os (o(o (,l (o(o CD (o(O --l (o(o @ o oC o)oo +{oo +{ o +{ N}o + os I t- oN o o{ ctoo ^. l o -l3 o.q II). -ro , x x o No a r0 o cn of @.g o. a ,I I I o ! 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I I MIAP SHOWING CODES OF RIVER STRETCHES OF THE OUEME BASIN l I i o o oC{ oC{N 0 ou51 ou520 0 c.2401 00 400 oC o,oo oC{ oC\G)o oC @oo o 0 oI I / I I I i l l L. -- (w ,'-- )\!_\ [; I l a o N@o U U lo uIF zo F2u ts UEF g t v X x X x @ @ o @ @ @ @ @ @ 6 @ @ @ @ m 6 o @ @ o m @ @ o @ @ @ @ o @ @ o o @ o @ @ @ o o @ 6 m o () C o @ o o o o E o E @ t t E o @ o o E E d i @ E o E o t @ i E t o c c o E tr @ t E I c & o I c I c o t I c c c c c c @ G c I c & c o E m c c I c c c I 6 I c r I I r I o o c c I 6 c c G G o o c r E E @ r D o o E E 6 o o E E o o o o t m o o o o @ @ x x @ o o o @ x x o o X x @ N t N o N 6 o @ @ @ o ts @ o @ o o @ o @ o o o o @ N @ o E @ o U @ E U oo l9 oo oo lo Noo ooNlI N@ oo l9 N@o o lo N@o a l o @ @o ooNl9 @@o ooNf, o ooo o lo ooo ooN lo 0o ol9 o oo fo o o :)o o lo N o lo o o fo o ooNlo oo l o oo l 9 o oo lIo o f 9 o N lo ooo oo l c oo o fo oo N o lo oo @ o l o oo lo o :lo oo o o l 6 lo lo oo o lo o oo @l o o @fo o o N fo NN lo o _1. 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Fl'q, -h! o 3 I(o @o IJ(o(0 @ Lo5 oI d zo o) II000$€ o ct q @ € o) c(o q Ef, C-E z =J C'o o =o ID I (o !r,5(., Gll Ioa o o I\.i H'lo* \ LASSO-SAHORO ':l-r( o -a GOVI o !( \. l a I a .-'l tOttlt o,'- '..;'lo o '(.., ,a r' ! -'i ' .\ SETEUSI r I PENESSOU ,'. .*(i I .-[_lJ IGBOMAKORO ATAFA FASSOW KONKONDJI KOG LANT, AGLAMASSO AKLADJEN t BANI I NAGNON GADJI t ,? ( ttq I KILIBO GARE M I t l I a \ ASSIO Z\-KEKERE a( ,l /) /, GO I TO J AVEGODOHE EPI VILLAGES IN THE OUEME BASIN I a .) .) \ l 1 DAIE:.OB/07 /99 SUMI'IARY OF tP IDEH IOLOG ICAL DATA OI'1S / ONCHO (EPICRALl ) Page: 3 PAYS : EENIN VisuaI Vi t tage Nurnber Vi [ [age Name 392 AEGAGCJLE 5025 AFFONOI I 5026 AFFONOT u 51t16 NBORKO 384 PENESSOULOIJ 401 KOGBETOHOJE LANTA TOGO Sucvey Duration Pop- Pop. Date Type ControI Census Examin. Prev. of mfs Acui ty CHFL Examin Number Prev BL ind Bt ind 7903 s -8.75 398 384 70 .2 16 -71 260 2 o .6 891 0 9l 10 'l .83 3 .83 176 160 110 125 3.1,7 * 2.80 142 S H 31.8 23.9 35 .0 26.0 51.1 60-1 81 .4 67.7 29.3 13.6 0 0.0 8910 s 9110 H 9001 7904 8304 8702 9110 9802 7905 9901 8912 s 9802 s 7903 9212 951 1 891 2 9110 9802 891 2 9802 891? 9802 1 .83 3 .83 167 179 90 161 111 165 366 382 170 331 ?92 1178 156 178 183 205 280 333 288 118 112 150 75 161 2?9 231 130 l. -50 * 2.50 113 13.22 3 1.8 s 2.08 7805 s -9.58 r55 123 10.6 4.08 94 0 0.0 ? 1 2 * D s H S -8.67 -1.67 -0.83 6.83 10.17 152 118 111 331 245 1.3 0.5 0.9 't3.97 42.O3 27 -39 1.43 0 -47 124 88 132 * *s s S 5-00 0.02 115 215 1 0 1.1 0.0 423 404 5079 790t+ S -8.67 339 303 0.00 11.33 -9.00 10.17 6.7 0.17 216 5 1.7 12.7 0.6 1,6.5 17 .5 7.7 '19. 1 3-6 0 -57 0.03 rf 0 .91 0. 10 1 .37 0. 13 ZASSA.N I GEENOUDO 396 GOVr COUNTRY : EENIN 5217 BAGBORHOE 5084 EGEELAKOTJKOE 5O8O ESSEHOUE 331 3lr6 11.6 0.8 * t * * COUNTRY : BENIN EASIN : KLCx.J-AGBALO/ZOU S s s 0.00 -6.00 7.92 '9.00 10.17 -9.00 10.17 230 178 96?61 311 298 57.7 20 .8 2.8 11 .22 1 -14 0.09 1.0 0.0 0.0 3 0 0 7 2 lPlsrx : KcrrFFo'rl r1 9010 s 9110 s 9802 s -8.17 6.83 10.17 '104 51 60 15.1 33.? 16.0 5 .55 2.39 0 .43 S 119 79 86 S c S S S S -9.00 6.83 10.17 15(. 141 132 4-t3 o -77 0 .33 2t5 86 5OB5 GANHAYADJ I 21 .B 2.9 t DAIt:08/07 /99 SUMMARY OT EPIDEHIOLOGICAL DATA OMS / ONCIIO (EPICRALl ) Page: 6 PAYS : BENIN VisuaI I Vi t tage Nurber Vi [ [age Name 5O?7 UARI.HARO 5028 UUUBERU COIJNTRY : BENIN 5032 BERADOUROU 5015 KOSSOU 5033 o.JROUBER0JNGA 5030 uARr COJNTRY : BENIN 5037 occxJALA COUNTRY : BENIN 5016 AGBORO-KAMEON 5475 DJABATA 5081 GBERE ?75 KABOUA 5041 KILIEO GARE 391 HOKA 5548 oKPA 5072 OJOGH I 5073 SANDEOU 398 IJOR I A COUNTRY : EENIN 5029 KIKA I I Survey Duration Pop. Pop. Date Type ControI Census Examin P rev. of mfs Acui ty CtIFL Exami n Number Prev BL ind BL ind 891 0 s 1 .83 112 296 60.1 12.19 58.7 1t .75 ** ** ** * ** ** ** 0.6 i* 127 0.3 ** * ** 212 1 0.3 8910 S 1.83 153 1o9 3t -9 3-92 B91O S 1.83 2?2 15t' 3t+'? 2'70 BASIN : NANON/oKPARA r{ 8910 s 1.83 282 20? t 2.2 6.99 8910 s 1.83 202 111 8909 s 1.75 207 148 * * * 11 .9 0.72 BASIN : OGCt/l{ONo 8910 s 1.83 133 109 52.6 10.99 BASIN : OKPARA 8910 s 1 -83 126 289 20.3 1 .37 rf r{ 9t111 9901 891 1 7805 9802 8910 s 91 11 tl 7903 891 1 9512 8911 s 9802 s 6-92 11.33 32t, s s S 250 177 155 115 373 222 189 111 211 123 32-? 8.1+ 37.7 37 -1 69.6 15.7 1.38 0 -17 17.5? 0.68 5 .84 5.65 8.61 5 -32 0.13 0.41 0.00 1 .85 0.31 8.01 8.85 r'! 0.00 10.17 1.83 3 -92 -9.08 10-17 9. 08 8. 00 1 .83 \.92 212 2t11 503 383 510 618 ?18 96 308 3 *1.92 143 126 134 20.5 0.99 1D s s s M 0.00 -9.08 8.00 196 16 297 53. 1 36.0 11.5 9-? 0.5 ?1 -5 9_9 115 19 219 o.2 0.3 0-2 9511 H 7.92 335 269 31.5 0.71 ?3t, 3 0.8 a 298 891 1 9512 161 83 s H D -8.67 97 96 s -1.67 71 50 BASIN: NANOUUIM/TEROU 23 -91 31 .A7 i{ 70 -t, 63.2 80 1.5 0.0 80 1 0.6 186 0 0.0 7901 8304 8910 9111 2 0 506 384 332 20t, 57 .6 51.3 S EASIN : HONONGO/OUEHECOUNTRY : EEulN H - 1n qn 1i) 5( 1 ',l',1 52 21q ) ns 1 1 1 DAIE:O8/07 /99 SUMHARY OF EPIDEMIOLOGICAL DATA OMS / ONCHO (EPICRAL1) Page: 8 Acui ty CMFL Examin PAYS : BENIN Visuat o Vi t tage Nunber Vi [ [age Name Survey Duration Pop. pop. Date Type ControI Census Examin. Prev. of mfs Nunber Prev Btind ELind 5459 AGONKOTJ 5078 AGONLIN.KPAHOI,J 381 ATCHAKPA 5880 ATCHAKPA(381 ) 315 BANICRI 409 EUE 407 H 3 LAil 390 IDADJO 205 KoKO 406 LASSO-SAH0R0 50/13 LEKPA 5547 '.IADENGBE 399 I,IBETEKOUKOU 5045 TOSSO 9410 s 6.83 296 270 6.9 0.16 * 7805 s -9.58 534 419 8.2 23.51 316 16 3.5 8912 9110 7901 9110 7904 s 9410 s 7903 9802 7805 D 9802 s 7904 D 8301 s 8702 M 9t112 S - 9.00 6.83 138 136 * *S S 144 27 106 102 215 382 260 211 76 109 2?9 131 172 229 2U 313 66 72.2 60.9 59.7 20.6 67.9 14.0 73.4 17.7 &.4 9.8 78-0 80.7 78.8 18.1 13 -97 4.90 11.17 0.37 28.89 0.55 36.79 0.60 19.59 40-24 17.n 0.41 i* 9904 s 11.33 375 301 3.8 0.13 217 1 0.7 7706 s -10.50 297 220 69.3 21.80 161 1 0.3 S s 2 1 3 1 5 3 4 * 0 S I't S 2 0. 00 6-83 0.00 6.83 0. 00 10 -17 -8-67 -1.67 - 0.83 7.00 276 318 365 131 186 73 217 76 * 0-9 0.2 314 527 13.13 1.11 o-6 0.1 334 276 s s 0.00 10.17 1.3 0.5 D 115 167 67 2.3 t 3-31 * 2.01 310 o.29 * ** t ** ** 0.0 7901 s -8.67 ?39 210 0.0 0.00 135 0 0.0 8910 s 1.83 774 151 20.4 0.86 * * ** 951 1 H 7.92 540 175 13.8 0.60 420 5 0-9 295 281 257 301 1.7 0.6 1.9 t* 181 95 219 * 5 2 6 * 5044 TANGUTEGA & ADJA 8910 s 1.83 212 126 51.4 8-3? 5039 TCHEDJANNAGNON * 891 0 91 10 9802 891 0 9111 99Ott 7706 9904 1 .83 3.83 10-17 1 .83 3.92 11.33 0.00 11.33 300 304 432 203 295 361 365 361 37.0 30.1 1.7 57 -3 55.6 5.1 61 .9 0-7 a 1.1 S H 191 ?71 251 8 .35 8. 06 0.18 259 a ? 1 0 S S 12.72 0.06 316 UEUE 195 15t+ 111 67 0.3 0.0 (o(o(o(o N) (o(o (j) i i(o(o(rl (o(o O) (o @ @ (o @ @ (o(o o (.o @(o (o(o o (o(o (o(o (o N) (o(o(,(o(o5t (o (o (o(o(o(l(Jl ,(I (Jr@r(o (o(ol(o (o O) O)rO) (o(o ! 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