@article{fdi:010091998,
  title = {{E}valuation of a novel biplex rapid diagnostic test for antibody responses to {L}oa loa and {O}nchocerca volvulus infections},
  author = {{C}ampillo, {J}{\'e}r{\'e}my and {B}iamonte, {M}. {A}. and {H}emilembolo, {M}. {C}. and {M}issamou, {F}. and {B}oussinesq, {M}ichel and {P}ion, {S}{\'e}bastien and {C}hesnais, {C}{\'e}dric},
  editor = {},
  language = {{ENG}},
  abstract = {{B}ackground {E}ndemic to {C}entral {A}frica, loiasis, caused by the vector-borne worm {L}oa loa, affects approximately 10 million individuals. {C}linical manifestations include transient angioedema ({C}alabar swellings), migration of the adult worm under the eye conjunctiva (eye worm) and less specific general symptoms. {L}oiasis presents a significant public health challenge because {L}. loa-infected individuals can develop serious adverse events after taking ivermectin, the drug used to combat onchocerciasis. {I}n this context, alternative interventions and rigorous diagnostic approaches are needed. {D}iagnosing loiasis is challenging because its main clinical manifestations are sporadic and non-specific. {T}he definitive diagnosis relies on identifying adult worms migrating beneath the conjunctiva, or microfilariae (pre-larvae) in blood smears. {H}owever, "occult loiasis" (infection without blood microfilariae) is frequent. {S}erological rapid antibody diagnostic tests ({ART}s) can provide an alternative diagnostic method. {W}e compared a novel {ART} simultaneously targeting onchocerciasis ({I}g{G}4 to {O}v-16 and {O}v{OC}3261, test line 1) and loiasis ({I}g{G}4 to {L}1-{SXP}-1, test line 2), called {I}g{G}4-{SXP}-1 biplex test) to the already established {L}oa-{ART} (all {I}g{G} isotypes to {L}l-{SXP}-1, called pan-{I}g{G}-{SXP}-1 test). {M}ethodology {B}lood samples underwent both {ART}s, read qualitatively and semi-quantitatively. {A}dditionally, blood smears, skin snips, {K}ato-{K}atz method for soil-transmitted helminthiases identification and eosinophilia measurements were performed. {Q}uestionnaires gathered demographic details and loiasis-related signs. {ART}s performance was compared using specific loiasis-related signs and microfilaremia as references. {D}iscordances between the two {ART}s were investigated using logistic regression models. {P}rincipal findings {O}ut of 971 participants, 35.4% had {L}. loa microfilaremia, 71.9% had already experienced loiasis-related signs, 85.1% were positive in the pan-{I}g{G}-{SXP}-1 test and 79.4% were positive in the {I}g{G}4-{SXP}-1 biplex test. {I}n the microfilariae-positive population, the sensitivity of the rapid tests was 87.4% for the pan-{I}g{G}-{SXP}-1 test and 88.6% for the prototype {I}g{G}4-{SXP}-1 biplex test. {S}ensitivity was similar for both {ART}s when using eye worm or {C}alabar swelling as references, but diagnostic performance varied based on microfilaremia levels and occult loiasis. {O}verall, {I}g{G}4-{SXP}-1 biplex test demonstrated a sensitivity of 84.1% and specificity of 47.6% for loiasis compared to the pan-{I}g{G}-{SXP}-1 test, leading to a {K}appa coefficient estimated at 0.27 +/- 0.03 for the qualitative results of the 2 {ART}s. {I}n the group that tested positive with the {P}an-{I}g{G} test but negative with the {I}g{G}4-specific test, there was a lower prevalence of {STH} infection (p = 0.008) and elevated eosinophilia (p<0.001) compared to the general tested population. {C}onclusion/{S}ignificance {T}he sensitivity of each test was good (84-85%) but the diagnostic agreement between the two {ART}s was poor, suggesting that {I}g{G} and {I}g{G}4 antibody responses should be interpreted differently. {T}he assessment of the innovative rapid diagnostic {I}g{G}4-{SXP}-1 biplex test, designed for onchocerciasis and loiasis, shows encouraging sensitivity but underlines the necessity for further in vitro assessment.},
  keywords = {{CONGO}},
  booktitle = {},
  journal = {{PL}o{S} {N}eglected {T}ropical {D}iseases},
  volume = {18},
  numero = {10},
  pages = {e0012567 [12 p.]},
  ISSN = {1935-2735},
  year = {2024},
  DOI = {10.1371/journal.pntd.0012567},
  URL = {https://www.documentation.ird.fr/hor/fdi:010091998},
}