The Galabat-Metema cross-border onchocerciasis focus: The first coordinated interruption of onchocerciasis transmission in Africa.
Journal
PLoS neglected tropical diseases
ISSN: 1935-2735
Titre abrégé: PLoS Negl Trop Dis
Pays: United States
ID NLM: 101291488
Informations de publication
Date de publication:
02 2020
02 2020
Historique:
received:
20
05
2019
accepted:
05
10
2019
entrez:
7
2
2020
pubmed:
7
2
2020
medline:
25
4
2020
Statut:
epublish
Résumé
Onchocerciasis transmission across international borders is not uncommon, yet a coordinated cross border stops mass drug administration (MDA) decision has not been documented. The Galabat-Metema focus involves neighboring districts on the border between Sudan and Ethiopia. Mass drug administration (MDA) was provided once and subsequently twice per year in this focus, with twice-per-year beginning in Ethiopia's Metema subfocus in 2016 and in the Sudan's Galabat subfocus in 2008. Ov16 ELISA-based serosurveys were conducted in 6072 children under 10 years of age in the Metema subfocus in 2014, and 3931 in the Galabat in 2015. Between 2014 and 2016, a total of 27,583 vector Simulium damnosum flies from Metema and 9,148 flies from Galabat were tested by pool screen PCR for Onchocerca volvulus O-150 DNA. Only 8 children were Ov16 seropositive (all in the Metema subfocus); all were negative by skin snip PCR. The upper limit of the 95% confidence interval (UCL) for Ov16 seropositive was <0.1% for the overall focus and 0.14 positive fly heads per 2000 (UCL = 0.39/2000). However, an entomological 'hotspot' was detected on the Wudi Gemzu river in Metema district. The hotspot was confirmed when 4 more positive fly pools were found on repeat testing in 2017 (1.04 L3/2000 flies (UCL = 2.26/2000). Information exchange between the two countries led to stopping MDA in a coordinated fashion in 2018, with the exception of the hotspot at Wudi Gemzu, where MDA with ivermectin was increased to every three months to hasten interruption of transmission. Coordinated stop MDA decisions were made by Sudan and Ethiopia based on data satisfying the World Health Organization's criteria for interruption of onchocerciasis transmission. Definitions of entomological 'hotspots' and buffer zones around the focus are proposed.
Sections du résumé
BACKGROUND
Onchocerciasis transmission across international borders is not uncommon, yet a coordinated cross border stops mass drug administration (MDA) decision has not been documented.
METHODS/PRINCIPLE FINDINGS
The Galabat-Metema focus involves neighboring districts on the border between Sudan and Ethiopia. Mass drug administration (MDA) was provided once and subsequently twice per year in this focus, with twice-per-year beginning in Ethiopia's Metema subfocus in 2016 and in the Sudan's Galabat subfocus in 2008. Ov16 ELISA-based serosurveys were conducted in 6072 children under 10 years of age in the Metema subfocus in 2014, and 3931 in the Galabat in 2015. Between 2014 and 2016, a total of 27,583 vector Simulium damnosum flies from Metema and 9,148 flies from Galabat were tested by pool screen PCR for Onchocerca volvulus O-150 DNA. Only 8 children were Ov16 seropositive (all in the Metema subfocus); all were negative by skin snip PCR. The upper limit of the 95% confidence interval (UCL) for Ov16 seropositive was <0.1% for the overall focus and 0.14 positive fly heads per 2000 (UCL = 0.39/2000). However, an entomological 'hotspot' was detected on the Wudi Gemzu river in Metema district. The hotspot was confirmed when 4 more positive fly pools were found on repeat testing in 2017 (1.04 L3/2000 flies (UCL = 2.26/2000). Information exchange between the two countries led to stopping MDA in a coordinated fashion in 2018, with the exception of the hotspot at Wudi Gemzu, where MDA with ivermectin was increased to every three months to hasten interruption of transmission.
CONCLUSION
Coordinated stop MDA decisions were made by Sudan and Ethiopia based on data satisfying the World Health Organization's criteria for interruption of onchocerciasis transmission. Definitions of entomological 'hotspots' and buffer zones around the focus are proposed.
Identifiants
pubmed: 32027648
doi: 10.1371/journal.pntd.0007830
pii: PNTD-D-19-00742
pmc: PMC7004312
doi:
Substances chimiques
Ivermectin
70288-86-7
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
e0007830Déclaration de conflit d'intérêts
The authors have declared that no competing interests exist.
Références
East Afr Med J. 1999 Aug;76(8):440-6
pubmed: 10520349
Trans R Soc Trop Med Hyg. 1957 May;51(3):253-6
pubmed: 13443016
Int Health. 2016 Mar;8(2):116-23
pubmed: 26152231
Arch Ital Sci Med Trop Parassitol. 1962 Dec;43:635-46
pubmed: 13946722
Am J Trop Med Hyg. 1983 Jan;32(1):123-37
pubmed: 6824118
Am J Trop Med Hyg. 2018 Sep;99(3):749-752
pubmed: 30014821
Int J Dermatol. 1991 Feb;30(2):130-3
pubmed: 2001904
Am J Trop Med Hyg. 2016 Nov 2;95(5):1037-1040
pubmed: 27352878
Am J Trop Med Hyg. 2007 Aug;77(2):334-41
pubmed: 17690408
Ann Trop Med Parasitol. 1994 Oct;88(5):463-74
pubmed: 7979636
Am J Trop Med Hyg. 2006 Jun;74(6):1026-33
pubmed: 16760515
BMC Infect Dis. 2019 May 28;19(1):477
pubmed: 31138151
Am J Trop Med Hyg. 2016 Aug 3;95(2):417-425
pubmed: 27215297
PLoS Negl Trop Dis. 2015 Jul 10;9(7):e0003922
pubmed: 26161558
Parasit Vectors. 2014 Jul 22;7:325
pubmed: 25053266
Ethiop Med J. 1975 Apr;13:53-9
pubmed: 1227869
Ann Trop Med Parasitol. 1987 Aug;81(4):405-19
pubmed: 3446029
J Infect Dis. 1994 Mar;169(3):686-9
pubmed: 8158053
Trop Geogr Med. 1975 Dec;27(4):365-70
pubmed: 1216316
Am J Trop Med Hyg. 2014 Feb;90(2):339-45
pubmed: 24343885
Parasit Vectors. 2018 Apr 11;11(1):237
pubmed: 29642939
Ethiop Med J. 1974 Oct;12(4):185-6
pubmed: 4470091
Int Health. 2018 Mar 1;10(suppl_1):i79-i88
pubmed: 29471335
Trans R Soc Trop Med Hyg. 1995 May-Jun;89(3):316-8
pubmed: 7660448
Ann Trop Med Parasitol. 2008 Sep;102 Suppl 1:23-4
pubmed: 18718150
Global Health. 2016 Aug 22;12(1):44
pubmed: 27549911