In Southern Nigeria Loa loa Blood Microfilaria Density is Very Low Even in Areas with High Prevalence of Loiasis: Results of a Survey Using the New LoaScope Technology
| Autor: | Cephas Ityonzughul, Barminas Kahansim, Emmanuel Emukah, Lindsay J. Rakers, Michael V. D’Ambrosio, Emily Griswold, Emmanuel Davies, Ifeoma Anagbogu, B. E. B. Nwoke, Joseph Kamgno, Yisa Saka, Emmanuel S. Miri, Thomas B. Nutman, Frank O. Richards, Matthew H. Bakalar, Daniel A. Fletcher |
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| Rok vydání: | 2018 |
| Předmět: |
medicine.medical_specialty
High prevalence biology business.industry 030231 tropical medicine Prevalence biology.organism_classification medicine.disease Microfilaria 03 medical and health sciences 0302 clinical medicine Infectious Diseases Ivermectin Virology Internal medicine parasitic diseases Epidemiology medicine Parasitology 030212 general & internal medicine Loa loa Onchocerciasis business Mass drug administration medicine.drug |
| Zdroj: | The American Journal of Tropical Medicine and Hygiene. 99:116-123 |
| ISSN: | 1476-1645 0002-9637 |
| Popis: | Ivermectin treatment can cause central nervous system adverse events (CNS-AEs) in persons with very high-density Loa loa microfilaremia (≥ 30,000 mf/mL blood). Hypoendemic onchocerciasis areas where L. loa is endemic have been excluded from ivermectin mass drug administration programs (MDA) because of the concern for CNS AEs. The rapid assessment procedure for L. loa (RAPLOA) is a questionnaire survey to assess history of eye worm. If ≥ 40% of respondents report eye worm, this correlates with ≥ 2% prevalence of very high-density loiasis microfilaremia, posing an unacceptable risk of CNS-AEs after MDA. In 2016, we conducted a L. loa study in 110 ivermectin-naive, suspected onchocerciasis hypoendemic villages in southern Nigeria. In previous RAPLOA surveys these villages had prevalences between 10% and 67%. We examined 10,605 residents using the LoaScope, a cell phone-based imaging device for rapidly determining the microfilaria (mf) density of L. loa infections. The mean L. loa village mf prevalence was 6.3% (range 0-29%) and the mean individual mf count among positives was 326 mf/mL. The maximum individual mf count was only 11,429 mf/mL, and among 2,748 persons sampled from the 28 villages with ≥ 40% RAPLOA, the ≥ 2% threshold of very high Loa mf density could be excluded with high statistical confidence (P < 0.01). These findings indicate that ivermectin MDA can be delivered in this area with extremely low risk of L. loa-related CNS-AEs. We also concluded that in Nigeria the RAPLOA survey methodology is not predictive of ≥ 2% prevalence of very high-density L. loa microfilaremia. |
| Databáze: | OpenAIRE |
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