{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T13:23:46Z","timestamp":1788873826904,"version":"build-2803163510"},"update-to":[{"DOI":"10.1371\/journal.pntd.0009623","type":"new_version","label":"New version","source":"publisher","updated":{"date-parts":[[2021,8,26]],"date-time":"2021-08-26T00:00:00Z","timestamp":1629936000000}}],"reference-count":31,"publisher":"Public Library of Science (PLoS)","issue":"8","license":[{"start":{"date-parts":[[2021,8,16]],"date-time":"2021-08-16T00:00:00Z","timestamp":1629072000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["www.plosntds.org"],"crossmark-restriction":false},"short-container-title":["PLoS Negl Trop Dis"],"abstract":"<jats:sec id=\"sec001\"><jats:title>Background<\/jats:title><jats:p><jats:italic>Loa loa<\/jats:italic>and<jats:italic>Mansonella perstans<\/jats:italic>\u2013the causative agents of loiasis and mansonellosis\u2014are vector-borne filarial parasites co-endemic in sub-Saharan Africa. Diagnosis of both infections is usually established by microscopic analysis of blood samples. It was recently established that the odds for detecting<jats:italic>Plasmodium spp<\/jats:italic>. is higher in capillary (CAP) blood than in venous (VEN) blood. In analogy to this finding this analysis evaluates potential differences in microfilaraemia of<jats:italic>L<\/jats:italic>.<jats:italic>loa<\/jats:italic>and<jats:italic>M<\/jats:italic>.<jats:italic>perstans<\/jats:italic>in samples of CAP and VEN blood.<\/jats:p><\/jats:sec><jats:sec id=\"sec002\"><jats:title>Methods<\/jats:title><jats:p>Recruitment took place between 2015 and 2019 at the CERMEL in Lambar\u00e9n\u00e9, Gabon and its surrounding villages. Persons of all ages presenting to diagnostic services of the research center around noon were invited to participate in the study. A thick smear of each 10 microliters of CAP and VEN blood was prepared and analysed by a minimum of two independent microscopists. Differences of log2-transformed CAP and VEN microfilaraemia were computed and expressed as percentages. Furthermore, odds ratios for paired data were computed to quantify the odds to detect microfilariae in CAP blood versus in VEN blood.<\/jats:p><\/jats:sec><jats:sec id=\"sec003\"><jats:title>Results<\/jats:title><jats:p>A total of 713 participants were recruited among whom 52% were below 30 years of age, 27% between 30\u201359 years of age and 21% above 60 years of age. Male-female ratio was 0.84. Among 152 participants with microscopically-confirmed<jats:italic>L<\/jats:italic>.<jats:italic>loa<\/jats:italic>infection median (IQR) microfilaraemia was 3,650 (275\u201311,100) per milliliter blood in CAP blood and 2,775 (200\u20138,875) in VEN blood (p&lt;0.0001), while among 102 participants with<jats:italic>M<\/jats:italic>.<jats:italic>perstans<\/jats:italic>this was 100 (0\u2013200) and 100 (0\u2013200), respectively (p = 0.44). Differences in linear models amount up to an average of +34.5% (95% CI: +11.0 to +63.0) higher<jats:italic>L<\/jats:italic>.<jats:italic>loa<\/jats:italic>microfilaria quantity in CAP blood versus VEN blood and for<jats:italic>M<\/jats:italic>.<jats:italic>perstans<\/jats:italic>it was on average higher by +24.8% (95% CI: +0.0 to +60.5). Concordantly, the odds for detection of microfilaraemia in CAP samples versus VEN samples was 1.24 (95% CI: 0.65\u20132.34) and 1.65 (95% CI: 1.0\u20132.68) for infections with<jats:italic>L<\/jats:italic>.<jats:italic>loa<\/jats:italic>and<jats:italic>M<\/jats:italic>.<jats:italic>perstans<\/jats:italic>, respectively.<\/jats:p><\/jats:sec><jats:sec id=\"sec004\"><jats:title>Conclusion<\/jats:title><jats:p>This analysis indicates that average levels of microfilaraemia of<jats:italic>L<\/jats:italic>.<jats:italic>loa<\/jats:italic>are higher in CAP blood samples than in VEN blood samples. This might have implications for treatment algorithms of onchocerciasis and loiasis, in which exact quantification of<jats:italic>L<\/jats:italic>.<jats:italic>loa<\/jats:italic>microfilaraemia is of importance. Furthermore, the odds for detection of<jats:italic>M<\/jats:italic>.<jats:italic>perstans<\/jats:italic>microfilariae was higher in CAP than in VEN blood which may pre-dispose CAP blood for detection of<jats:italic>M<\/jats:italic>.<jats:italic>perstans<\/jats:italic>infection in large epidemiological studies when sampling of large blood quantities is not feasible. No solid evidence for a higher odds of<jats:italic>L<\/jats:italic>.<jats:italic>loa<\/jats:italic>microfilariae detection in CAP blood was revealed, which might be explained by generally high levels of<jats:italic>L<\/jats:italic>.<jats:italic>loa<\/jats:italic>microfilaraemia in CAP and VEN blood above the limit of detection of 100 microfilariae\/ml. Yet, it cannot be excluded that the study was underpowered to detect a moderate difference.<\/jats:p><\/jats:sec>","DOI":"10.1371\/journal.pntd.0009623","type":"journal-article","created":{"date-parts":[[2021,8,16]],"date-time":"2021-08-16T18:53:23Z","timestamp":1629140003000},"page":"e0009623","update-policy":"https:\/\/doi.org\/10.1371\/journal.pntd.corrections_policy","source":"Crossref","is-referenced-by-count":16,"title":["Diagnostic performance of capillary and venous blood samples in the detection of Loa loa and Mansonella perstans microfilaraemia using light microscopy"],"prefix":"10.1371","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2012-6327","authenticated-orcid":true,"given":"Johannes","family":"Mischlinger","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rella Zoleko","family":"Manego","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2658-8706","authenticated-orcid":true,"given":"Ghyslain","family":"Mombo-Ngoma","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8980-3149","authenticated-orcid":true,"given":"Dorothea","family":"Ekoka Mbassi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nina","family":"Hackbarth","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3383-651X","authenticated-orcid":true,"given":"Franck-Aurelien","family":"Ekoka Mbassi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Saskia Dede","family":"Davi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7727-7823","authenticated-orcid":true,"given":"Ruth","family":"Kreuzmair","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6136-8170","authenticated-orcid":true,"given":"Luzia","family":"Veletzky","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jennifer","family":"Hergeth","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8213-4912","authenticated-orcid":true,"given":"Wilfrid Nzebe","family":"Ndoumba","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paul","family":"Pitzinger","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7375-3685","authenticated-orcid":true,"given":"Mirjam","family":"Groger","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pierre Blaise","family":"Matsiegui","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3197-5946","authenticated-orcid":true,"given":"Ay\u00f4la Akim","family":"Adegnika","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Selidji Todagbe","family":"Agnandji","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1427-3002","authenticated-orcid":true,"given":"Bertrand","family":"Lell","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9259-1885","authenticated-orcid":true,"given":"Michael","family":"Ramharter","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2021,8,16]]},"reference":[{"key":"pntd.0009623.ref001","unstructured":"Centers for Disease Control and Prevention. Loiasis. 2021 [cited 3 Mar 2021]. Available: https:\/\/www.cdc.gov\/parasites\/loiasis\/"},{"key":"pntd.0009623.ref002","unstructured":"Centers for Disease Control and Prevention. Mansonellosis. 2021 [cited 8 Mar 2021]. Available: https:\/\/www.cdc.gov\/dpdx\/mansonellosis\/index.html"},{"key":"pntd.0009623.ref003","doi-asserted-by":"crossref","first-page":"1339","DOI":"10.1016\/S1473-3099(20)30256-5","article-title":"Burden of disease in Gabon caused by loiasis: a cross-sectional survey","volume":"20","author":"L Veletzky","journal-title":"Lancet Infect Dis. 2020"},{"key":"pntd.0009623.ref004","doi-asserted-by":"crossref","first-page":"108","DOI":"10.1016\/S1473-3099(16)30405-4","article-title":"Excess mortality associated with loiasis: a retrospective population-based cohort study","volume":"17","author":"CB Chesnais","year":"2017","journal-title":"Lancet Infect Dis"},{"key":"pntd.0009623.ref005","volume-title":"Hunter\u2019s Tropical Medicine and Emerging Infectious Diseases. 9th ed.","author":"E Ryan","year":"2012"},{"key":"pntd.0009623.ref006","doi-asserted-by":"crossref","first-page":"715","DOI":"10.1179\/136485906X112194","article-title":"Loiasis.","volume":"100","author":"M Boussinesq","year":"2006","journal-title":"Ann Trop Med Parasitol"},{"key":"pntd.0009623.ref007","doi-asserted-by":"crossref","first-page":"353","DOI":"10.1016\/S1473-3099(13)70263-9","article-title":"Loa loa-does it deserve to be neglected","volume":"14","author":"WG Metzger","year":"2014","journal-title":"Lancet Infect Dis"},{"key":"pntd.0009623.ref008","doi-asserted-by":"crossref","first-page":"945","DOI":"10.1007\/s00436-008-1312-x","article-title":"Analysis of the 24-h microfilarial periodicity of Mansonella perstans","volume":"104","author":"SM Asio","year":"2009","journal-title":"Parasitol Res"},{"key":"pntd.0009623.ref009","doi-asserted-by":"crossref","first-page":"127","DOI":"10.1080\/00034983.1917.11684131","article-title":"Observations on the Periodicity of Microfilaria Nocturna","volume":"11","author":"W Yorke","year":"1917","journal-title":"Ann Trop Med Parasitol"},{"key":"pntd.0009623.ref010","first-page":"295","article-title":"Comparative densities of Wuchereria bancrofti microfilaria in paired samples of capillary and venous blood. Trop Med Parasitol Off organ","volume":"39","author":"ML Eberhard","year":"1988","journal-title":"Dtsch Tropenmedizinische Gesellschaft Dtsch Gesellschaft fur Tech Zusammenarbeit"},{"key":"pntd.0009623.ref011","doi-asserted-by":"crossref","first-page":"174","DOI":"10.4269\/ajtmh.1973.22.174","article-title":"Comparisons of microfilaria density in blood sampled by finger-prick, venipuncture, and ingestion by mosquitoes","volume":"22","author":"DJ Gubler","year":"1973","journal-title":"Am J Trop Med Hyg Am J Trop Med Hyg"},{"key":"pntd.0009623.ref012","first-page":"472","article-title":"Further evidence of a skewed distribution of microfilariae in capillary blood. Trop Med Parasitol Off organ","volume":"40","author":"JW Dickerson","year":"1989","journal-title":"Dtsch Tropenmedizinische Gesellschaft Dtsch Gesellschaft fur Tech Zusammenarbeit"},{"key":"pntd.0009623.ref013","doi-asserted-by":"crossref","first-page":"506","DOI":"10.1016\/0035-9203(91)90237-S","article-title":"A quantitative approach to the relationship between Wuchereria bancrofti microfilaria counts by venous blood filtration and finger-prick blood films","volume":"85","author":"M Sabry","year":"1991","journal-title":"Trans R Soc Trop Med Hyg"},{"key":"pntd.0009623.ref014","doi-asserted-by":"crossref","first-page":"264","DOI":"10.1111\/j.1365-3156.1996.tb00037.x","article-title":"Studies on the periodicity and intravascular distribution of Wuchereria bancrofti microfilariae in paired samples of capillary and venous blood from Recife","volume":"1","author":"G Dreyer","year":"1996","journal-title":"Brazil. Trop Med Int Health"},{"key":"pntd.0009623.ref015","doi-asserted-by":"crossref","first-page":"463","DOI":"10.1016\/0035-9203(83)90113-X","article-title":"The concentration of Mansonella ozzardi microfilariae in skin capillaries","volume":"77","author":"MA Moraes","year":"1983","journal-title":"Trans R Soc Trop Med Hyg"},{"key":"pntd.0009623.ref016","first-page":"37","article-title":"Clinical manifestations of loiasis in an endemic area in the Congo. Trop Med Parasitol Off organ","volume":"41","author":"F Noireau","year":"1990","journal-title":"Dtsch Tropenmedizinische Gesellschaft Dtsch Gesellschaft fur Tech Zusammenarbeit"},{"key":"pntd.0009623.ref017","doi-asserted-by":"crossref","first-page":"361","DOI":"10.1080\/00034983.1950.11685462","article-title":"Studies on the epidemiology of filariasis in West Africa, with special reference to the British Cameroons and the Niger Delta. I. Methods of survey for infections with Loa loa and Acanthocheilonema perstans","volume":"44","author":"WE KERSHAW","year":"1950","journal-title":"Ann Trop Med Parasitol"},{"key":"pntd.0009623.ref018","first-page":"390","article-title":"Comparison of thick blood smear and saponin haemolysis for the detection of Loa loa and Mansonella perstans infections","volume":"93","author":"F Noireau","year":"1990","journal-title":"J Trop Med Hyg"},{"key":"pntd.0009623.ref019","doi-asserted-by":"crossref","first-page":"1296","DOI":"10.1093\/infdis\/jiy319","article-title":"Use of Capillary Blood Samples Leads to Higher Parasitemia Estimates and Higher Diagnostic Sensitivity of Microscopic and Molecular Diagnostics of Malaria Than Venous Blood Samples","volume":"218","author":"J Mischlinger","year":"2018","journal-title":"J Infect Dis"},{"key":"pntd.0009623.ref020","doi-asserted-by":"crossref","first-page":"130","DOI":"10.1186\/s12889-017-4045-x","article-title":"Demography, maternal health and the epidemiology of malaria and other major infectious diseases in the rural department Tsamba-Magotsi, Ngounie Province, in central African Gabon","volume":"17","author":"RZ Manego","year":"2017","journal-title":"BMC Public Health"},{"key":"pntd.0009623.ref021","doi-asserted-by":"crossref","first-page":"500","DOI":"10.1007\/s00508-020-01794-8","article-title":"Development of sustainable research excellence with a global perspective on infectious diseases: Centre de Recherches M\u00e9dicales de Lambar\u00e9n\u00e9 (CERMEL), Gabon","volume":"133","author":"M Ramharter","year":"2021","journal-title":"Wien Klin Wochenschr."},{"key":"pntd.0009623.ref022","first-page":"249","article-title":"Model-based imputation approach for data analysis in the presence of non-detects","volume":"53","author":"K Krishnamoorthy","year":"2009","journal-title":"Ann Occup Hyg"},{"key":"pntd.0009623.ref023","doi-asserted-by":"crossref","first-page":"1153","DOI":"10.1136\/bmj.312.7039.1153","article-title":"The use of transformation when comparing two means","volume":"312","author":"JM Bland","year":"1996","journal-title":"BMJ"},{"key":"pntd.0009623.ref024","doi-asserted-by":"crossref","first-page":"1079","DOI":"10.1136\/bmj.312.7038.1079","article-title":"Transformations, means, and confidence intervals","volume":"312","author":"JM Bland","year":"1996","journal-title":"BMJ"},{"key":"pntd.0009623.ref025","doi-asserted-by":"crossref","first-page":"100582","DOI":"10.1016\/j.eclinm.2020.100582","article-title":"Individual risk of post-ivermectin serious adverse events in subjects infected with Loa loa","volume":"28","author":"CB Chesnais","year":"2020","journal-title":"EClinicalMedicine."},{"key":"pntd.0009623.ref026","doi-asserted-by":"crossref","first-page":"980","DOI":"10.1111\/tmi.13124","article-title":"Validity and reliability of methods to microscopically detect and quantify malaria parasitaemia","volume":"23","author":"J Mischlinger","year":"2018","journal-title":"Trop Med Int Health"},{"key":"pntd.0009623.ref027","doi-asserted-by":"crossref","first-page":"10413","DOI":"10.7189\/jogh.08.010413","article-title":"Behavioural and clinical predictors for Loiasis","volume":"8","author":"J Mischlinger","year":"2018","journal-title":"J Glob Health"},{"key":"pntd.0009623.ref028","doi-asserted-by":"crossref","first-page":"2044","DOI":"10.1056\/NEJMoa1705026","article-title":"A Test-and-Not-Treat Strategy for Onchocerciasis in Loa loa-Endemic Areas","volume":"377","author":"J Kamgno","year":"2017","journal-title":"N Engl J Med"},{"key":"pntd.0009623.ref029","doi-asserted-by":"crossref","first-page":"102","DOI":"10.1016\/S1473-3099(19)30554-7","article-title":"Implications for annual retesting after a test-and-not-treat strategy for onchocerciasis elimination in areas co-endemic with Loa loa infection: an observational cohort study","volume":"20","author":"SD Pion","journal-title":"Lancet Infect Dis. 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