Progress towards elimination of onchocerciasis transmission in Mali: A "pre-stop MDA" survey in 18 transmission zones.

BACKGROUND: Onchocerciasis control activities in Mali began in 1975 with vector larviciding carried out by the Onchocerciasis Control Programme (OCP), followed by the distribution of ivermectin from 1998 until the closure of the OCP in 2002. At that time, epidemiological evaluations, using skin snip microscopy and O-150 pool screening PCR in black flies, indicated that the disease had been largely controlled as a public health problem. Ivermectin distribution was nevertheless continued after 2002 in 34 of the 75 health districts in Mali as these were known to still be meso- or hyper-endemic for onchocerciasis. In addition, the onchocerciasis sites known to be hypo-endemic for onchocerciasis benefited from the distribution of ivermectin treatment as part of the mass drug administration (MDA) program for lymphatic filariasis. Various entomological and epidemiological evaluations have now indicated that Mali may have achieved successful interruption of onchocerciasis transmission. METHODS: A series of cross-sectional surveys to update vector breeding sites throughout the endemic areas, followed by a pre-stop ivermectin mass drug administration (Pre-stop MDA) survey, were undertaken in 2019-2020. Based on breeding site findings, historical epidemiological assessments, and vector collection site maps, 18 operational transmission zones (OTZ) were delineated within which a total of 104 first line villages were selected for evaluation. Dried blood spots (DBS) samples were collected from 10,400 children (5-9 years old) from these 104 first line villages and processed for the presence of OV16 antibody using a lab-based rapid diagnostic test. RESULTS: Within the 544 Simulium damnosum s.l. breeding sites visited in all five endemic onchocerciasis endemic regions of Mali 18.01% (98/544) were seen to be active with the presence of at least one stage of S. damnosum. The overall prevalence of OV16 positive children was 0.45% (47/10,400). However, two hotspots were identified: 2.60% (13/500) seroprevalence in the OTZ number 5 in Kayes Region and 1.40% (7/500) in the OTZ number 1 of Sikasso Region. CONCLUSION: These data show that onchocerciasis prevalence in the five endemic regions has declined to levels that indicate that Stop-MDA surveys should be now carried out in most of the OTZ except for one in the Kayes Region. This latter site will need additional ivermectin treatment before reevaluation, and an OTZ in the Sikasso Region requires revaluation before possibly reinitiating MDA.

Enhancing onchocerciasis elimination program management: A biological approach to deciding when to begin Stop Mass Drug Administration activities.

Understanding when it is the appropriate time to stop administering the drugs in a chemotherapy-centered treatment program such as onchocerciasis remains a challenge due to cost, imperfect testing procedures, and a lack of long-term experience. Different approaches for assessing when a program can begin the extensive stop-treatment surveys have been recommended, and tested, with varying results. We describe here a practical approach that is based on information on both transmission as well as infection. This new protocol first defines operational transmission zones (OTZs) based on vector breeding sites followed by an epidemiological assessment of the resident populations adjacent to these breeding sites. Basing decisions to stop MDA treatment based on breeding site locations (i.e., transmission zones) rather than on political administrative units, is a practical, cost-effective approach. Importantly, this biology-based approach is more closely related to the actual state of onchocerciasis transmission.

Serological Evaluation of Onchocerciasis and Lymphatic Filariasis Elimination in the Bakoye and Falémé Foci, Mali.

BACKGROUND: Ivermectin-based onchocerciasis elimination, reported in 2009-2012, for Bakoye and Falémé, Mali, supported policy-shifting from morbidity control to elimination of transmission (EOT). These foci are coendemic with lymphatic filariasis (LF). In 2007-2016 mass ivermectin plus albendazole administration was implemented. We report Ov16 (onchocerciasis) and Wb123 (LF) seroprevalence after 24-25 years of treatment to determine if onchocerciasis EOT and LF elimination as a public health problem (EPHP) have been achieved. METHODS: The SD Bioline Onchocerciasis/LF Ig[immunoglobulin]G4 biplex rapid diagnostic test (RDT) was used in 2186 children aged 3-10 years in 13 villages (plus 2 hamlets) in Bakoye and in 2270 children in 15 villages (plus 1 hamlet) in Falémé. In Bakoye, all-age serosurveys were conducted in 3 historically hyperendemic villages (1867 individuals aged 3 -78 years). RESULTS: In Bakoye, IgG4 seropositivity was 0.27% (95% confidence interval [CI] = .13%-.60%) for both Ov16 and Wb123 antigens. In Falémé, Ov16 and Wb123 seroprevalence was 0.04% (95% CI = .01%-.25%) and 0.09% (95% CI = .02%-.32%), respectively. Ov16-seropositive children were from historically meso/hyperendemic villages. Ov16 positivity was <2% in ≤14 year-olds, and 16% in ≥40 year-olds. Wb123 seropositivity was <2% in ≤39 year-olds, reaching 3% in ≥40 year-olds. CONCLUSIONS: Notwithstanding uncertainty in the biplex RDT sensitivity, Ov16 and Wb123 seroprevalence among children in Bakoye and Falémé is consistent with EOT (onchocerciasis) and EPHP (LF) since stopping treatment in 2016. The few Ov16-seropositive children should be skin-snip polymerase chain reaction tested and followed up.

Arteriography of three models of gastric oesophagoplasty: the whole stomach, a wide gastric tube and a narrow gastric tube.

The esogastric anastomotic fistula,occurring after the replacement of esophagus by the stomach, is a post-operative complication always feared and awaited. Apart from other causes, there exist the anatomical dispositions notably the vascular and technical factors that stress this potential risk despite certain advantages of esophagogastroplasty. The goal of our study was to study the arterial distribution of the gastric transplants in order to identify the better modalities of their making. We used 39 stomachs taken from fresh cadavers of autochtone subjects. After a modeling treatment using three different techniques, they were subjected to a radiographic opacification of the right gastro-epiploic artery with sulphate of barium follow by an x-rays in incidence full-face (25 kv, 10 mAS). It was a matter of 15 entire stomachs (E.E.) with denudation of the small curvature, of 12 wide gastric tubes (W.T.) prepared according to the Akiyama technique modified and of 12 narrow tubes (N.T.) tubulized according to the Marmuse method. We studied the anastomotic type of the gastro-epiploic arterial circle according to the classification of Koskas, the collateral branches of the arterial circles of the gastric curvatures, the antral and corporeal anastomosis of these circles and the distribution anastomotic at the level of the summit of the anastomotic. Only 28 pieces (15 E.E., 8 W.T. and 5 N.T.) were able to be the object of a complete angiographic exploitation. The anastomosis of the arterial circle was type I in 64.1% of the cases, type II in 15.4% of the cases, type III in 15.4% of the cases and type IV in 5.1% of the cases. The average number of collateral branches originating from gastro-epiploic arterial circle was respectively 24, 17 and 22 for the E.E., the W.T. and the N.T. Only the two first ones presented collateral branches being borne of the small curvature circle. Fifty per cent of the N.T. did not possess any antral or corporeal anastomosis between the two arterial circles; some of them were even for a quarter of the W.T. In the case of gastric tubulization there existed an irrigation defect of the summit of the plasty for a third of the N.T. and a quarter of the W.T., despite a constant intramural bridge anastomosis between the two gastro-epiploic arteries. The usage of the entire stomach must be recommended for gastric oesophagoplasty; but when the operative indications require a resection of the small curvature it is preferable to use a wide gastric tube whose diameter respects the two left third of the initial width of the organ.