Iridocyclitis, cataract, papillitis and chorioretinitis in onchocerciasis patients (n = 82) post ivermectin treatment. Differences were evaluated using Pearson's chi-square test.

$<p>PIT =  post initial treatment.</p><p>PES =  Posterior Eye Segment.</p>$$<p>Other Lesions: Phtyse, Pupille scleroatrophic, Synechie post trauma, Pigments on posterior Capsule.</p>§§<p>Other Lesions: Phtyse, dead O.volvulus microfilariae on posterior capsule.</p>&&<p>Other Lesions: optic cup/disc >0.5.</p>§§§<p>Other Lesions  =  retina detachment from the retinal pigment epithelium, drusen.</p><p>*p<0.001 compared to 4 years PIT;</p><p>**p<0.001 compared to before ivermectin;</p><p>***p<0.0001 compared to before ivermectin and 4 years PIT.</p>&<p>p<0.01 compared to before ivermectin.</p

Ocular anomalies not caused by <i>Onchocerca volvulus</i> infection in patients (n = 82) examined before ivermectin treatment, and at 4 and 23 years post initial ivermectin treatment (PIT).

<p>Ocular anomalies not caused by <i>Onchocerca volvulus</i> infection in patients (n = 82) examined before ivermectin treatment, and at 4 and 23 years post initial ivermectin treatment (PIT).</p

Sustainable Control of Onchocerciasis: Ocular Pathology in Onchocerciasis Patients Treated Annually with Ivermectin for 23 Years: A Cohort Study

<div><p>The evolution and persistence of ocular pathology was assessed in a cohort of <i>Onchocerca volvulus</i> infected patients treated annually with ivermectin for 23 years. Patients were resident in rural Central and Kara Region of Togo and ocular examinations included testing of visual acuity, slit lamp examination of the anterior eye segment and the eye fundus by ophthalmoscopy. Before ivermectin treatment, vivid <i>O.volvulus</i> microfilariae (MF) were observed in the right and left anterior eye chamber in 52% and 42% of patients (n = 82), and dead MF were seen in the right and left cornea in 24% and 15% of cases, respectively. At 23 years post initial treatment (PIT), none of the patients (n = 82) presented with MF in the anterior chamber and cornea. A complete resolution of punctate keratitis (PK) lesions without observable corneal scars was present at 23 years PIT (p<0.0001), and sclerosing keratitits (SK) lessened by half, but mainly in patients with lesions at early stage of evolution. Early-stage iridocyclitis diminished from 42%(rE) and 40%(lE) to 13% (rE+lE)(p<0.0001), but advanced iridocyclitis augmented (p<0.001) at 23 years PIT compared to before ivermectin. Advanced-stage papillitis and chorioretinitis did not regress, while early-stage papillitis present in 28%(rE) and 27%(lE) of patients at before ivermectin regressed to 17%(rE) and 18%(lE), and early-stage chorioretinitis present in 51%(rE+lE) of cases at before ivermectin was observed in 12%(rE) and 13%(lE) at 23 years PIT (p<0.0001). Thus, regular annual ivermectin treatment eliminated and prevented the migration of <i>O. volvulus</i> microfilariae into the anterior eye chamber and cornea; keratitis punctata lesions resolved completely and early-stage sclerosing keratitits and iridocyclitis regressed, whilst advanced lesions of the anterior and posterior eye segment remained progressive. In conclusion, annual ivermectin treatments may prevent the emergence of ocular pathology in those populations still exposed to <i>O.volvulus</i> infection.</p><p><i>Trial Registration</i>: <a href="http://www.pactr.org" target="_blank">www.pactr.org</a><a href="http://www.pactr.org/ATMWeb/appmanager/atm/atmregistry?dar=true&tNo=PACTR201303000464219" target="_blank">PACTR201303000464219</a>)</p></div

Microfilaria in the anterior chamber of the eye, the cornea, and puctate and sclerosing keratitis in onchocerciasis patients (n = 82) post ivermectin treatment. Differences were evaluated using Pearson's chi-square test.

$<p>PIT =  post initial treatment.</p><p>*p<0.001 compared to 4 years PIT;</p><p>**p<0.001 compared to before ivermectin;</p><p>***p<0.0001 compared to before ivermectin and 4 years PIT.</p

Causes of bilateral visual impairment and blindness in the onchocerciasis patients' cohort (n = 82) before ivermectin treatment, and at 4 years and 23 years post initial treatment (PIT).

<p>The patients' visual acuity was graded according to WHO criteria; blind were those with a visual acuity on the right (RE) or left eye (LE) or both eyes (RLE) of less than 1/20 (3/60 or unable to count fingers at 3 meters); impaired vision had those with a visual acuity between 1/20 (3/60) and less than 3/10 (6/18); good vision had those with a visual acuity equal or greater than 3/10.</p

Spearman’s rank correlation analyses of ocular pathologies and visual acuity of the right eye (RE) in the survey participants and significant associations (p<0.05).

<p>Spearman’s rank correlation analyses of ocular pathologies and visual acuity of the right eye (RE) in the survey participants and significant associations (p<0.05).</p

<i>Onchocerca volvulus</i> infection and serological prevalence, ocular onchocerciasis and parasite transmission in northern and central Togo after decades of <i>Simulium damnosum</i> s.l. vector control and mass drug administration of ivermectin

<div><p>Background</p><p>Mass drug administration (MDA) of ivermectin has become the main intervention to control onchocerciasis or “river blindness”. In Togo, after many years of MDA, <i>Onchocerca volvulus</i> infection has declined dramatically, and elimination appears achievable, but in certain river basins the current situation remains unknown. We have conducted parasitological, serological, ophthalmological, and entomological assessments in northern and central Togo within the river basins of Ôti, Kéran and Mô.</p><p>Methodology/Principal findings</p><p>Examinations were completed in 1,455 participants from 11 onchocerciasis sentinel villages, and <i>O</i>. <i>volvulus</i> transmission by <i>Simulium damnosum</i> sensu lato (s.l.) was evaluated. In children (aged 1–10 years), the prevalence of microfilariae (Mf) was 2.3% and in adults it ranged from 5.1 to 13.3%. Positive IgG4 responses to <i>O</i>. <i>volvulus</i> adult (crude) worm antigen (OvAg) and the recombinant Ov16 antigen were in all-ages 48.7% and 34.4%, and 29.1% and 14.9% in children, respectively. In the river basin villages of Kéran, Mô and Ôti, the IgG4 seroprevalences to OvAg in children were 51.7%, 23.5% and 12.7%, respectively, and to the Ov16 antigen 33.3% (Kéran) and 5.2% (Ôti). Onchocerciasis ocular lesions (punctate keratitis, evolving iridocyclitis and chorioretinitis) were observed in children and young adults. <i>O</i>. <i>volvulus</i>-specific DNA (Ov150) was detected by poolscreen in vector samples collected from Tchitchira/Kéran(22.8%), Bouzalo/Mô(11.3%), Baghan/Mô(2.9%) and Pancerys/Ôti(4.9%); prevalences of <i>O</i>. <i>volvulus</i> infection in <i>S</i>. <i>damnosum</i> s.l. were, respectively, 1%, 0.5%, 0.1% and 0.2%.</p><p>Conclusions/Significance</p><p>In the northern and central river basins in Togo, interruption of <i>O</i>. <i>volvulus</i> transmission has not yet been attained. Patent <i>O</i>. <i>volvulus</i> infections, positive antibody responses, progressive ocular onchocerciasis were diagnosed, and parasite transmission by <i>S</i>. <i>damnosum</i> s.l. occurred close to the survey locations. Future interventions may require approaches selectively targeted to non-complying endemic populations, to the seasonality of parasite transmission and national onchocerciasis control programs should harmonize cross-border MDA as a coordinated intervention.</p></div

<i>Onchocerca volvulus</i> microfilarial prevalence (% Mf-positive) by age and sex groups in the survey participants from NOCP sentinel villages in central and northern Togo.

<p>The number of examined participants, the Mf-positive status and the percentage of Mf-positive individuals are shown. From n = 41 study participants the age is missing. The 95% confidence intervals (95% CI, Wilson score interval) of the prevalence values are indicated in square brackets. (* significant differences between female and male survey participation).</p

<i>Onchocerca volvulus</i> adult worm (OvAg) and recombinant Ov16 antigen-specific IgG4 reactivity (optical densities; OD) in participants and positive and negative IgG4 responses in age groups.

<p>In A and C the data on antigen-specific IgG4 reactivity are shown as mean optical densities (ODs) with 95% confidence intervals for the means (diamonds). The data presented in box plots show the median OD per age group with the 25% and 75% quartiles and the 1.5x of the interquartile range. In B and D the antigen-specific-IgG4 positive and negative responses in age groups are indicated (in %).</p

Collection of <i>Simulium damnosum</i> s.l. at the catch point at the Mô river (village of Bouzalo) caught per person (one day per week).

<p>The annual biting rate (ABR) from January 2016 until December 2016 was calculated by multiplying the number of blackflies caught daily by the number of days per week for each month to add up to 12 months. Collections were conducted from 7am to 6pm with alternating fly catchers every two hours as described in Material and Methods.</p