03767nas a2200421   4500000000100000008004100001260004400042653001900086653002500105653001200130653000800142653001300150653002200163100001200185700002700197700001400224700001400238700001500252700001700267700001300284700001300297700001300310700001400323700001400337700001500351700001200366700002200378700001400400700001100414700001300425700001500438245011800453856008400571300000900655490000700664520266000671022001403331       2024                            d  bSpringer Science and Business Media LLC10aOnchocerciasis10aLymphatic filariasis10aMapping10aPCR10aSerology10aEquatorial Guinea1 aNcogo P1 aHernández-González A1 aTa-Tang T1 aRedondo L1 aÁlvarez A1 aPerteguer MJ1 aRubio JM1 aNguema R1 aNguema J1 aGarcía M1 aReguero L1 aValverde T1 aLanza M1 aCerrada-Gálvez L1 aRebollo M1 aCano J1 aBenito A1 aHerrador Z00aApproaching onchocerciasis elimination in Equatorial Guinea: Near zero transmission and public health implication  uhttps://idpjournal.biomedcentral.com/counter/pdf/10.1186/s40249-024-01254-9.pdf  a1-110 v133 a<p><strong>Background:</strong> Onchocerciasis and lymphatic filariasis (LF) are endemic in Equatorial Guinea with notable variations in disease incidence between island and mainland regions. Historically, efforts to control and map these diseases were concentrated in Bioko Island, where loiasis is absent, allowing for targeted onchocerciasis interruption strategies. With the cessation of onchocerciasis transmission on Bioko and no reported cases on Annobon island, assessing the transmission status in the previously unaddressed mainland region has become imperative. Mapping efforts in mainland Equatorial Guinea have proven low to moderate level of transmission for LF and onchocerciasis, although the results so far have not been very conclusive. The current study aims to update the prevalence estimates for onchocerciasis and LF in mainland Equatorial Guinea using various diagnostic techniques.</p>

<p><strong>Methods: </strong>This is the first cross-sectional study carried out to estimate the prevalence of onchocerciasis and LF in the mainland area of Equatorial Guinea, from September to December 2019, based on the combination of skin snip biopsies, thick blood smears, laboratory serological tests (ELISA tests for the detection of IgG4 antibodies against Onchocerca volvulus recombinant antigen Ov16 and Wuchereria bancrofti recombinant antigen Wb123) and molecular laboratory tests. Frequencies and prevalence rates, along with 95% confidence intervals for interval estimation of a binomial proportion, were computed.</p>

<p><strong>Results: </strong>The overall onchocerciasis seroprevalence calculated for the study was 0.3% (95% CI: 0.1 to 0.5%). Microscopic examination of skin biopsies from the eight individuals seropositive for Ov16, out of the 3951 individuals initially tested, revealed no O. volvulus microfilariae. However, DNA extracted from one skin snip was successfully amplified, with subsequent sequencing confirming the presence of O. volvulus. Among the 3951 individuals, 182 were found to have anti-Wb123 antibodies, suggesting exposure to W. bancrofti, with an estimated seroprevalence of 4.6% (95% CI: 4.0 to 5.3%). Microscopy and Filaria-real time-PCR (F-RT-PCR) analysis for W. bancrofti were negative across all samples.</p>

<p><strong>Conclusions:</strong> The findings indicate that onchocerciasis may no longer constitutes a public health problem in Equatorial Guinea, positioning the country on the verge of achieving elimination. Additionally, the mapped prevalence of LF will facilitate the formulation of national strategies aimed at eradicating filariases countrywide. Graphical Abstract</p>
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