The Impact of Loa Loa Microfilaraemia on Research Subject Retention During a Whole Sporozoite Malaria Vaccine Trial in Equatorial Guinea

Overview

Journal Trans R Soc Trop Med Hyg

Publisher Oxford University Press

Specialties Public Health
Tropical Medicine

Date 2022 Apr 8

PMID 35394038

Authors

Stephen R Manock

Vicente Urbano Nsue

Ally Olotu

Maximillian Mpina

Elizabeth Nyakarungu

Jose Raso

Ali Mtoro

Martin Eka Ondo Mangue

Beltran Ekua Ntutumu Pasialo

Rufino Nguema

Pouria Riyahi

Tobias Schindler

Claudia Daubenberger

L W Preston Church

Peter F Billingsley

Thomas L Richie

Salim Abdulla

Stephen L Hoffman

Affiliations

Soon will be listed here.

Abstract

Loa loa microfilariae were found on thick blood smears (TBSs) from 8 of 300 (2.7%) residents of Bioko Island, Equatorial Guinea, during a Plasmodium falciparum sporozoite malaria vaccine clinical trial. Only one subject was found to have microfilaraemia on his first exam; parasites were not discovered in the other seven until subsequent TBSs were performed, at times many weeks into the study. All infected individuals were asymptomatic, and were offered treatment with diethylcarbamazine, per national guidelines. L. loa microfilaraemia complicated the enrolment or continued participation of these eight trial subjects, and only one was able to complete all study procedures. If ruling out loiasis is deemed to be important during clinical trials, tests that are more sensitive than TBSs should be performed.

References

Metzger W, Mordmuller B . Loa loa-does it deserve to be neglected?. Lancet Infect Dis. 2013; 14(4):353-7. DOI: 10.1016/S1473-3099(13)70263-9. View

Mordmuller B, Surat G, Lagler H, Chakravarty S, Ishizuka A, Lalremruata A . Sterile protection against human malaria by chemoattenuated PfSPZ vaccine. Nature. 2017; 542(7642):445-449. PMC: 10906480. DOI: 10.1038/nature21060. View

Sissoko M, Healy S, Katile A, Omaswa F, Zaidi I, Gabriel E . Safety and efficacy of PfSPZ Vaccine against Plasmodium falciparum via direct venous inoculation in healthy malaria-exposed adults in Mali: a randomised, double-blind phase 1 trial. Lancet Infect Dis. 2017; 17(5):498-509. PMC: 6803168. DOI: 10.1016/S1473-3099(17)30104-4. View

Jongo S, Church L, Mtoro A, Chakravarty S, Ruben A, Swanson P . Safety and Differential Antibody and T-Cell Responses to the Sporozoite Malaria Vaccine, PfSPZ Vaccine, by Age in Tanzanian Adults, Adolescents, Children, and Infants. Am J Trop Med Hyg. 2019; 100(6):1433-1444. PMC: 6553883. DOI: 10.4269/ajtmh.18-0835. View

Pion S, Tchatchueng-Mbougua J, Chesnais C, Kamgno J, Gardon J, Chippaux J . Effect of a Single Standard Dose (150-200 μg/kg) of Ivermectin on Microfilaremia: Systematic Review and Meta-analysis. Open Forum Infect Dis. 2019; 6(4):ofz019. PMC: 6449757. DOI: 10.1093/ofid/ofz019. View

Moya L, Herrador Z, Ta-Tang T, Rubio J, Perteguer M, Hernandez-Gonzalez A . Evidence for Suppression of Onchocerciasis Transmission in Bioko Island, Equatorial Guinea. PLoS Negl Trop Dis. 2016; 10(7):e0004829. PMC: 4957785. DOI: 10.1371/journal.pntd.0004829. View

Negesse Y, Lanoie L, NEAFIE R, CONNOR D . Loiasis: "Calabar" swellings and involvement of deep organs. Am J Trop Med Hyg. 1985; 34(3):537-46. DOI: 10.4269/ajtmh.1985.34.537. View

Herrick J, Metenou S, Makiya M, Taylar-Williams C, Law M, Klion A . Eosinophil-associated processes underlie differences in clinical presentation of loiasis between temporary residents and those indigenous to Loa-endemic areas. Clin Infect Dis. 2014; 60(1):55-63. PMC: 4296126. DOI: 10.1093/cid/ciu723. View

Bouyou Akotet M, Owono-Medang M, Mawili-Mboumba D, Moussavou-Boussougou M, Nzenze Afene S, Kendjo E . The relationship between microfilaraemic and amicrofilaraemic loiasis involving co-infection with Mansonella perstans and clinical symptoms in an exposed population from Gabon. J Helminthol. 2015; 90(4):469-75. DOI: 10.1017/S0022149X15000607. View

10.

Emukah E, Rakers L, Kahansim B, Miri E, Nwoke B, Griswold E . In Southern Nigeria Blood Microfilaria Density is Very Low Even in Areas with High Prevalence of Loiasis: Results of a Survey Using the New LoaScope Technology. Am J Trop Med Hyg. 2018; 99(1):116-123. PMC: 6085777. DOI: 10.4269/ajtmh.18-0163. View

11.

Jongo S, Urbano V, Church L, Olotu A, Manock S, Schindler T . Immunogenicity and Protective Efficacy of Radiation-Attenuated and Chemo-Attenuated PfSPZ Vaccines in Equatoguinean Adults. Am J Trop Med Hyg. 2020; 104(1):283-293. PMC: 7790068. DOI: 10.4269/ajtmh.20-0435. View

12.

Herrick J, Legrand F, Gounoue R, Nchinda G, Montavon C, Bopda J . Posttreatment Reactions After Single-Dose Diethylcarbamazine or Ivermectin in Subjects With Loa loa Infection. Clin Infect Dis. 2017; 64(8):1017-1025. PMC: 5850646. DOI: 10.1093/cid/cix016. View

13.

Puente S, Ramirez-Olivencia G, Lago M, Subirats M, Bru F, Perez-Blazquez E . Loiasis in sub-Saharan migrants living in Spain with emphasis of cases from Equatorial Guinea. Infect Dis Poverty. 2020; 9(1):16. PMC: 7006425. DOI: 10.1186/s40249-020-0627-4. View

14.

Zoure H, Wanji S, Noma M, Amazigo U, Diggle P, Tekle A . The geographic distribution of Loa loa in Africa: results of large-scale implementation of the Rapid Assessment Procedure for Loiasis (RAPLOA). PLoS Negl Trop Dis. 2011; 5(6):e1210. PMC: 3125145. DOI: 10.1371/journal.pntd.0001210. View

15.

Chippaux J, Bouchite B, Boussinesq M, Ranque S, Baldet T, Demanou M . Impact of repeated large scale ivermectin treatments on the transmission of Loa loa. Trans R Soc Trop Med Hyg. 1998; 92(4):454-8. DOI: 10.1016/s0035-9203(98)91091-4. View

16.

Ta T, Moya L, Nguema J, Aparicio P, Miguel-Oteo M, Cenzual G . Geographical distribution and species identification of human filariasis and onchocerciasis in Bioko Island, Equatorial Guinea. Acta Trop. 2018; 180:12-17. DOI: 10.1016/j.actatropica.2017.12.030. View

17.

Okonkwo O, Hassan A, Alarape T, Akanbi T, Oderinlo O, Akinye A . Removal of adult subconjunctival Loa loa amongst urban dwellers in Nigeria. PLoS Negl Trop Dis. 2018; 12(11):e0006920. PMC: 6261630. DOI: 10.1371/journal.pntd.0006920. View

18.

Buell K, Whittaker C, Chesnais C, Jewell P, Pion S, Walker M . Atypical Clinical Manifestations of Loiasis and Their Relevance for Endemic Populations. Open Forum Infect Dis. 2019; 6(11):ofz417. PMC: 6824532. DOI: 10.1093/ofid/ofz417. View

19.

Olotu A, Urbano V, Hamad A, Eka M, Chemba M, Nyakarungu E . Advancing Global Health through Development and Clinical Trials Partnerships: A Randomized, Placebo-Controlled, Double-Blind Assessment of Safety, Tolerability, and Immunogenicity of PfSPZ Vaccine for Malaria in Healthy Equatoguinean Men. Am J Trop Med Hyg. 2017; 98(1):308-318. PMC: 5928718. DOI: 10.4269/ajtmh.17-0449. View

20.

Seder R, Chang L, Enama M, Zephir K, Sarwar U, Gordon I . Protection against malaria by intravenous immunization with a nonreplicating sporozoite vaccine. Science. 2013; 341(6152):1359-65. DOI: 10.1126/science.1241800. View