The Onchocerciasis Elimination Program for the Americas: a history of partnership

Blanks, Jennifer; Richards, Frank O.; Beltrán, Fernando J.; Collins, Richard C.; Álvarez, Elizabeth; Flores, Guillermo Zea; Bauler, B; Cedillos, Rolando A; Heisler, Michele; Brandling-Bennett, David; Baldwin, William R.; Bayona, Manuel; Klein, Robert E.; Jacox, M

doi:10.1590/s1020-49891998000600002

Cited by 59 publications

(42 citation statements)

References 5 publications

(6 reference statements)

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“…17,19,20 Fundamentally, however, the credit for the 21.2 million ivermectin treatment encounters reported here belongs to district level health care workers and community residents. It should also be stressed that the treatments achieved resulted from both the delivery of tablets and the health education and training needed to empower those with onchocerciasis to be full partners in the program and to sustain the drug delivery process.…”

Section: Discussionmentioning

confidence: 94%

“…14Ϫ16 Through the Onchocerciasis Elimination Program for the Americas (OEPA), the GRBP assisted in all endemic areas of all six endemic countries in the Americas (Brazil, Colombia, Ecuador, Guatemala, Mexico, and Venezuela). 17 At risk villages (arv). Rapid assessment techniques were used to define villages in need of mass ivermectin treatment.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

The Carter Center's assistance to river blindness control programs: establishing treatment objectives and goals for monitoring ivermectin delivery systems on two continents.

Richards¹,

Miri²,

Katabarwa³

et al. 2001

The American Journal of Tropical Medicine and Hygiene

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Section: Discussionmentioning

confidence: 94%

Section: Methodsmentioning

confidence: 99%

The Carter Center's assistance to river blindness control programs: establishing treatment objectives and goals for monitoring ivermectin delivery systems on two continents.

Richards¹,

Miri²,

Katabarwa³

et al. 2001

The American Journal of Tropical Medicine and Hygiene

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“…A small secretariat for the OEPA, partnership, based in Guatemala City, provides technical, administrative, advocacy, and some financial support to national programs. 15 The Carter Center has shouldered the administrative responsibilities for the secretariat for the last 20 years. A Program Coordinating Committee meets twice per year to act as the technical steering committee for OEPA.…”

Section: Resultsmentioning

confidence: 99%

“…The 14 OEPA (with its headquarters in Guatemala City) together with other partners, began to provide sustained technical and financial support for the MSPAS MDA program in 1994, 15 and by 1996 annual MDA rounds were established in the CEZ. In 2000, the MSPAS made its policy to provide FIGURE 1.…”

Section: Methodsmentioning

confidence: 99%

One Hundred Years After Its Discovery in Guatemala by Rodolfo Robles, Onchocerca volvulus Transmission Has Been Eliminated from the Central Endemic Zone

Richards¹,

Rizzo²,

Espinoza³

et al. 2015

The American Society of Tropical Medicine and Hygiene

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Abstract. We report the elimination of Onchocerca volvulus transmission from the Central Endemic Zone (CEZ) of onchocerciasis in Guatemala, the largest focus of this disease in the Americas and the first to be discovered in this hemisphere by Rodolfo Robles Valverde in 1915. Mass drug administration (MDA) with ivermectin was launched in 1988, with semiannual MDA coverage reaching at least 85% of the eligible population in > 95% of treatment rounds during the 12-year period, 2000-2011. Serial parasitological testing to monitor MDA impact in sentinel villages showed a decrease in microfilaria skin prevalence from 70% to 0%, and polymerase chain reaction (PCR)-based entomological assessments of the principal vector Simulium ochraceum s.l. showed transmission interruption by 2007. These assessments, together with a 2010 serological survey in children 9-69 months of age that showed Ov16 IgG4 antibody prevalence to be < 0.1%, meeting World Health Organization (WHO) guidelines for stopping MDA, and treatment was halted after 2011. After 3 years an entomological assessment showed no evidence of vector infection or recrudescence of transmission. In 2015, 100 years after the discovery of its presence, the Ministry of Health of Guatemala declared onchocerciasis transmission as having been eliminated from the CEZ. INTRODUCTION Human onchocerciasis (river blindness) is caused byOnchocerca volvulus, a tissue-dwelling filarial nematode transmitted by certain species of the genus Simulium.1 Adult male and female worms form fibrous, often palpable, subcutaneous onchocercomas ("nodules"), in which fertilized female worms produce microfilariae (mf). The mf leave the nodule and reside in the dermis. They may also enter the eyes. Human disease results largely from death of the mf, which results in inflammation, itching, visual impairment, and blindness. The Simulium ("black fly") vectors breed in rapidly flowing rivers and streams and become infected when they ingest mf during a blood meal; in competent black fly species, mf develop into third stage larvae that can infect humans when the vector takes a subsequent blood meal. There are no important animal reservoirs of O. volvulus to maintain the transmission cycle independent of the human population itself. Human onchocerciasis is thought to have originated in Africa when Onchocerca species in ungulates adapted to man; the parasite is believed to have been brought to the Americas through the Atlantic slave trade.3 Transmission was only focally established in the Americas, in contrast to the extensive transmission zones that exist in Africa. In the Americas, due to a limited distribution of competent vectors, transmission zones ("foci") are small and sharply delimited geographically, and are generally maintained by high vector biting rates. Before control measures were implemented, there were 13 foci in six countries in Latin America (Brazil, Colombia, Ecuador, Guatemala, Mexico, and Venezuela), with an overall human population at risk in 2013 of just over 500,000 persons. 4Guatemala...

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“…This program has as its main strategy the elimination of the disease through the semi-annually distribution of the ivermectin (Mectizan™) for 10 to 15 years to the population at risk (Blanks et al 1998). This approach has been demonstrated to result in a decrease of microfilariae rates in the skin which gives immediate clinical benefit and reduces the possibility of infecting new vectors which is expected to reduce or eliminate transmission (Greene et al 1989, Duke 1990.…”

mentioning

confidence: 99%

Detection of Onchocerca volvulus (Nematoda: Onchocercidae) infection in vectors from Amazonian Brazil following mass Mectizan™ distribution

Marchon-Silva

Caër

Post

et al. 2007

Mem. Inst. Oswaldo Cruz

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According to the World Health Organization (WHO 2000) more than 120 million people, worldwide, live under risk of acquiring onchocerciasis and 18 million are infected. One third of those infected manifest dermatitis and 500,000 present serious visual problems with approximately 1% developing blindness. Indeed, 270,000 individuals are blind from this etiology worldwide. This disease is caused by infection with Onchocerca volvulus (Nematoda: Onchocercidae) and is endemic to Africa, the Arabian Peninsula, and Latin America, where it occurs in parts of Brazil, Colombia, Ecuador, Guatemala, Mexico, and Venezuela. In Brazil, the only known active focus of the disease is located in the Amazonian region, and extends across the border to form the southern focus of Venezuela. It corresponds to more or less the whole territory of the Yanomami in the northwest of the state of Roraima and central north of the state of Amazonas (Shelley 1991(Shelley , 2002, exposing 13,767 indians to the infection (Funasa 2002).In the New World the control program has been sponsored by the Onchocerciasis Elimination Program for the Americas (OEPA). This program has as its main strategy the elimination of the disease through the semi-annually distribution of the ivermectin (Mectizan™) for 10 to 15 years to the population at risk (Blanks et al. 1998). This approach has been demonstrated to result in a decrease of microfilariae rates in the skin which gives immediate clinical benefit and reduces the possibility of infecting new vectors which is expected to reduce or eliminate transmission (Greene et al. 1989, Duke 1990.In simuliids, the classic parasitological method for the parasite detection (by dissection and examination of vectors) is unsuitable for high throughput analysis because it is time consuming and requires high levels of training, for example it requires the accurate morphological identification of the larvae.Since the 1990s, the polymerase chain reaction (PCR) amplification of an Onchocerca-specific repeated DNA sequence (O-150) has been used to detect and identify O. volvulus (Meredith et al. 1991, 1994, Zimmerman et al. 1992, Fischer et al. 1996, Merriweather & Unnasch 1996, Unnasch & Meredith 1996. However, in populations of vectors with a low prevalence of infection (as would be expected during an onchocerciasis control program using ivermectin, for example) large numbers of flies would have to be processed to obtain an accurate estimate of infection, which would be timeconsuming and expensive. However, the O-150 PCR has proved to have a high analytical sensitivity, being able to detect a single infected fly in pools containing up to 100 flies (Katholi et al. 1995). Therefore, a statistical model has been developed by Katholi et al. (1995) to determine the prevalence of infection in the simuliid population, based on the prevalence of infection in pools of vectors, and it has been demonstrated that this method reveals a prevalence of infected flies statistically similar to the rates obtained by traditional entomological dissect...

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The Onchocerciasis Elimination Program for the Americas: a history of partnership

Cited by 59 publications

References 5 publications

The Carter Center's assistance to river blindness control programs: establishing treatment objectives and goals for monitoring ivermectin delivery systems on two continents.

The Carter Center's assistance to river blindness control programs: establishing treatment objectives and goals for monitoring ivermectin delivery systems on two continents.

One Hundred Years After Its Discovery in Guatemala by Rodolfo Robles, Onchocerca volvulus Transmission Has Been Eliminated from the Central Endemic Zone

Detection of Onchocerca volvulus (Nematoda: Onchocercidae) infection in vectors from Amazonian Brazil following mass Mectizan™ distribution

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