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Gobbi F, Bottieau E, Bouchaud O, Buonfrate D, Salvador F, Rojo-Marcos G, Rodari P, Clerinx J, Treviño B, Herrera-Ávila JP, Neumayr A, Calleri G, Angheben A, Rothe C, Zammarchi L, Guerriero M, Bisoffi Z. Comparison of different drug regimens for the treatment of loiasis-A TropNet retrospective study. PLoS Negl Trop Dis 2018; 12:e0006917. [PMID: 30383753 PMCID: PMC6233929 DOI: 10.1371/journal.pntd.0006917] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 11/13/2018] [Accepted: 10/11/2018] [Indexed: 11/18/2022] Open
Abstract
Background Loa loa infection is endemic in limited areas of West-Central Africa. Loiasis has been associated with excess mortality, but clinical studies on its treatment are scant, particularly outside endemic areas, due to the rarity of cases diagnosed. Methodology/Principal findings With this retrospective TropNet (European Network for Tropical Medicine and Travel Health) study, we aimed at outlining the treatment schedules followed by different reference centers for tropical medicine across Europe. We gathered information about 238 cases of loiasis, 165 of which had follow up data. The regimens followed by the different centers were heterogeneous. The drugs most frequently administered were: diethylcarbamazine alone (74/165, 45.1%), ivermectin alone (41/165, 25%), albendazole + ivermectin (21/164, 11.6%), ivermectin + diethylcarbamazine (16/165, 9.7%). Conclusions/Significance The management of loiasis substantially differs across specialized travel clinics in Europe. These discrepancies could be due to different local protocols as well as to (un)availability of the drugs. An harmonization of clinical protocols for the treatment of loiasis would be suggested across reference centers for tropical medicine in Europe. Loa loa is a worm which infects millions of people living in wide forested areas of central Africa. The infection is rarely diagnosed outside Africa, and cases are mainly referred to referral centers on tropical medicine. Aim of this study was to describe the treatment and management of patients diagnosed with loiasis in some referral centers for tropical medicine in Europe. The results showed that different health centers treat the patients with different drugs/drug combinations. On the basis of the availability of the drugs and on the data observed, common protocols might be recommended for the participating centers.
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Affiliation(s)
- Federico Gobbi
- IRCCS Center for Tropical Diseases, Ospedale Sacro Cuore Don Calabria, Negrar, Verona, Italy
- * E-mail:
| | - Emmanuel Bottieau
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Olivier Bouchaud
- Service des Maladies Infectieuses et Tropicales, CHU Avicenne, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Dora Buonfrate
- IRCCS Center for Tropical Diseases, Ospedale Sacro Cuore Don Calabria, Negrar, Verona, Italy
| | - Fernando Salvador
- Infectious Diseases Department, Vall d’Hebron University Hospital, PROSICS Barcelona, Barcelona, Spain
| | - Gerardo Rojo-Marcos
- Hospital Universitario Príncipe de Asturias, Alcalá de Henares, Madrid, Spain
| | - Paola Rodari
- IRCCS Center for Tropical Diseases, Ospedale Sacro Cuore Don Calabria, Negrar, Verona, Italy
| | - Jan Clerinx
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Begoña Treviño
- International Health Unit Vall d’Hebron-Drassanes, PROSICS Barcelona, Barcelona, Spain
| | | | - Andreas Neumayr
- Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Guido Calleri
- Unit A of Infectious and Tropical Diseases, Amedeo di Savoia Hospital, Turin, Italy
| | - Andrea Angheben
- IRCCS Center for Tropical Diseases, Ospedale Sacro Cuore Don Calabria, Negrar, Verona, Italy
| | - Camilla Rothe
- University Hospital Medical Centre, Hamburg, Germany
- LMU Medical Centre, Munich, Germany
| | - Lorenzo Zammarchi
- Dipartimento di Medicina Sperimentale e Clinica, Università di Firenze; SOD Malattie Infettive e Tropicali, Azienda Ospedaliero Universitaria Careggi, Florence, Italy
| | | | - Zeno Bisoffi
- IRCCS Center for Tropical Diseases, Ospedale Sacro Cuore Don Calabria, Negrar, Verona, Italy
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Wanji S, Chounna Ndongmo WP, Fombad FF, Kengne-Ouafo JA, Njouendou AJ, Longang Tchounkeu YF, Koudou B, Bockarie M, Fobi G, Roungou JB, Enyong PA. Impact of repeated annual community directed treatment with ivermectin on loiasis parasitological indicators in Cameroon: Implications for onchocerciasis and lymphatic filariasis elimination in areas co-endemic with Loa loa in Africa. PLoS Negl Trop Dis 2018; 12:e0006750. [PMID: 30226900 PMCID: PMC6161907 DOI: 10.1371/journal.pntd.0006750] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 09/28/2018] [Accepted: 08/13/2018] [Indexed: 11/18/2022] Open
Abstract
Background Loiasis is a filarial infection endemic in the rainforest zone of west and central Africa particularly in Cameroon, Gabon, Republic of Congo, and Democratic Republic of the Congo. Repeated treatments with ivermectin have been delivered using the annual community directed treatment with ivermectin (CDTI) approach for several years to control onchocerciasis in some Loa loa-Onchocerca volvulus co-endemic areas. The impact of CDTI on loiasis parasitological indicators is not known. We, therefore, designed this cross sectional study to explore the effects of several rounds of CDTI on parasitological indicators of loiasis. Methodology/Principal findings The study was conducted in the East, Northwest and Southwest 2 CDTI projects of Cameroon. Individuals who consented to participate were interviewed for ivermectin treatment history and enrolled for parasitological screening using thick smears. Ivermectin treatment history was correlated with loiasis prevalence/intensity. A total of 3,684 individuals were recruited from 36 communities of the 3 CDTI projects and 900 individuals from 9 villages in a non-CDTI district. In the East, loiasis prevalence was 29.3% (range = 24.2%–34.6%) in the non-CDTI district but 16.0% (3.3%–26.6%) in the CDTI district with 10 ivermectin rounds (there were no baseline data for the latter). In the Northwest and Southwest 2 districts, reductions from 30.5% to 17.9% (after 9 ivermectin rounds) but from 8.1% to 7.8% (not significantly different after 14 rounds) were registered post CDTI, respectively. Similar trends in infection intensity were observed in all sites. There was a negative relationship between adherence to ivermectin treatment and prevalence/intensity of infection in all sites. None of the children (aged 10–14 years) examined in the East CDTI project harboured high (8,000–30,000 mf/ml) or very high (>30,000 mf/ml) microfilarial loads. Individuals who had taken >5 ivermectin treatments were 2.1 times more likely to present with no microfilaraemia than those with less treatments. Conclusion In areas where onchocerciasis and loiasis are co-endemic, CDTI reduces the number of, and microfilaraemia in L. loa-infected individuals, and this, in turn, will help to prevent non-neurological and neurological complications post-ivermectin treatment among CDTI adherents. Loa loa (the parasite causing loiasis), also known as African eye worm, is endemic in forest areas of west and central Africa. In several of the endemic areas, it co-exists with onchocerciasis and lymphatic filariasis (LF). Because of the benefit individuals suffering from onchocerciasis could have by taking ivermectin where the disease is severe, despite the risk of developing serious side-effects due to being co-infected with L. loa, mass drug administration (MDA) of ivermectin for the control of onchocerciasis has been ongoing in areas where the two diseases overlap. Ivermectin is also effective against loiasis. It is, therefore, hypothesized that several years of ivermectin MDA against onchocerciasis in those areas may have impacted on parasitological indicators for loiasis. In particular, we assess the impact of annual community directed treatment with ivermectin (CDTI) on loiasis with specific reference to the relationship between adherence to treatment and the risk of developing severe (nervous system) complications following ivermectin treatment. We also discuss the feasibility of eliminating onchocerciasis and/or LF in areas endemic for L. loa with ivermectin as the sole intervention tool.
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Affiliation(s)
- Samuel Wanji
- Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
- * E-mail:
| | - Winston Patrick Chounna Ndongmo
- Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Fanny Fri Fombad
- Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Jonas Arnaud Kengne-Ouafo
- Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Abdel Jelil Njouendou
- Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | | | - Benjamin Koudou
- Centre for Neglected Tropical Diseases (incorporating the Lymphatic Filariasis Support Centre), Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Moses Bockarie
- Centre for Neglected Tropical Diseases (incorporating the Lymphatic Filariasis Support Centre), Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Grace Fobi
- African Program for Onchocerciasis Control (APOC), Ouagadougou, Burkina Faso
| | | | - Peter A. Enyong
- Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
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Kelly-Hope LA, Blundell HJ, Macfarlane CL, Molyneux DH. Innovative Surveillance Strategies to Support the Elimination of Filariasis in Africa. Trends Parasitol 2018; 34:694-711. [PMID: 29958813 DOI: 10.1016/j.pt.2018.05.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 05/18/2018] [Accepted: 05/30/2018] [Indexed: 01/18/2023]
Abstract
Lymphatic filariasis (LF) and onchocerciasis are two neglected tropical diseases (NTDs) of public health significance targeted for global elimination. The World Health Organization (WHO) African Region is a priority region, with the highest collective burden of LF and onchocerciasis globally. Coendemic loiasis further complicates elimination due to the risk of adverse events associated with ivermectin treatment. A public health framework focusing on health-related data, systematic collection of data, and analysis and interpretation of data is used to highlight the range of innovative surveillance strategies required for filariasis elimination. The most recent and significant developments include: rapid point-of-care test (POCT) diagnostics; clinical assessment tools; new WHO guidelines; open-access online data portals; mHealth platforms; large-scale prevalence maps; and the optimisation of mathematical models.
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Affiliation(s)
- Louise A Kelly-Hope
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Harriet J Blundell
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Cara L Macfarlane
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - David H Molyneux
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK
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Arrey-Agbor DB, Nana-Djeunga HC, Mogoung-Wafo AE, Mafo M, Danwe C, Kamgno J. Case Report: Probable Case of Spontaneous Encephalopathy Due to Loiasis and Dramatic Reduction of Loa loa Microfilariaemia with Prolonged Repeated Courses of Albendazole. Am J Trop Med Hyg 2018; 99:112-115. [PMID: 29741149 DOI: 10.4269/ajtmh.17-0664] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Loiasis is a vector-borne parasitic disease caused by the filarial nematode Loa loa and transmitted by the tabanid vectors from the genus Chrysops. Loa loa infection is associated with clinical manifestations such as pruritus, migratory transient edema, passage of adult worm in the bulbar conjunctiva, retinal damage, glomerular damage, albuminuria, pleural effusion, hydrocele, and endomyocardial fibrosis. Data reporting the occurrence of spontaneous encephalopathy associated with loiasis are very scanty. Severe adverse events occurring post-ivermectin administered in the framework of the fight against onchocerciasis and/or lymphatic filariasis in loiasis co-endemic areas have been closely associated with very high L. loa microfilariaemia. Different regimens have been used to lower L. loa microfilariaemia before definitive treatment, and many discrepancies have been reported. We report the case of a patient who was admitted to a health facility and hospitalized for 34 days for altered consciousness, blurred vision, headache, and chills. After other potential diagnoses were eliminated, the patient was confirmed with encephalopathy due to loiasis and referred to the Centre for Research on Filariasis and other Tropical Diseases (CRFilMT). On admission at CRFilMT, the patient was harboring 28,700 microfilariae per milliliter of blood (mf/mL), and after four 21-day courses of 400 mg daily albendazole, the L. loa microfilariaemia lowered to 5,060 mf/mL. The patient was then treated with ivermectin 3 mg and a total clearance of microfilariae was observed, with satisfactory clinical evolution and no adverse event. This case study further confirmed that albendazole is effective against L. loa, but might necessitate a longer course.
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Affiliation(s)
- Divine B Arrey-Agbor
- Centre for Research on Filariasis and other Tropical Diseases (CRFilMT), Yaoundé, Cameroon
| | - Hugues C Nana-Djeunga
- Department of Animal Biology and Physiology, Parasitology and Ecology Laboratory, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon.,Centre for Research on Filariasis and other Tropical Diseases (CRFilMT), Yaoundé, Cameroon
| | - Aude E Mogoung-Wafo
- Centre for Research on Filariasis and other Tropical Diseases (CRFilMT), Yaoundé, Cameroon
| | - Mirabelle Mafo
- Centre for Research on Filariasis and other Tropical Diseases (CRFilMT), Yaoundé, Cameroon
| | | | - Joseph Kamgno
- Centre for Research on Filariasis and other Tropical Diseases (CRFilMT), Yaoundé, Cameroon.,Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Yaoundé, Cameroon
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55
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Njambe Priso GD, Lissom A, Ngu LN, Nji NN, Tchadji JC, Tchouangueu TF, Ambada GE, Ngane CSS, Dafeu BL, Djukouo L, Nyebe I, Magagoum S, Ngoh AA, Herve OF, Garcia R, Gutiérrez A, Okoli AS, Esimone CO, Njiokou F, Park CG, Waffo AB, Nchinda GW. Filaria specific antibody response profiling in plasma from anti-retroviral naïve Loa loa microfilaraemic HIV-1 infected people. BMC Infect Dis 2018; 18:160. [PMID: 29618330 PMCID: PMC5885382 DOI: 10.1186/s12879-018-3072-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 03/26/2018] [Indexed: 12/14/2022] Open
Abstract
Background In West and Central Africa areas of endemic Loa loa infections overlap with regions of high prevalence of human immunodeficiency virus type 1 (HIV-1) infections. Because individuals in this region are exposed to filarial parasites from birth, most HIV-1 infected individuals invariably also have a history of filarial parasite infection. Since HIV-1 infection both depletes immune system and maintains it in perpetual inflammation, this can hamper Loa loa filarial parasite mediated immune modulation, leading to enhanced loaisis. Methods In this study we have assessed in plasma from asymptomatic anti-retroviral (ARV) naïve Loa loa microfilaraemic HIV-1 infected people the filarial antibody responses specific to a filariasis composite antigen consisting of Wbgp29-BmR1-BmM14-WbSXP. The antibody responses specific to the filariasis composite antigen was determined by enzyme linked immunosorbent assay (ELISA) in plasma from ARV naïve Loa loa microfilaraemic HIV-1 infected participants. In addition the filarial antigen specific IgG antibody subclass profiles were also determined for both HIV-1 positive and negative people. Results Both Loa loa microfilaraemic HIV-1 positive and negative individuals showed significantly higher plasma levels of IgG1 (P < 0.0001), IgG2 (P < 0.0001) and IgM (P < 0.0001) relative to amicrofilaraemic participants. A significant increase in IgE (P < 0.0001) was observed exclusively in Loa loa microfilaraemic HIV-1 infected people. In contrast there was a significant reduction in the level of IgG4 (p < 0.0001) and IgG3 (P < 0.0001) in Loa loa microfilaraemic HIV-1 infected individuals. Conclusions Loa loa microfilaraemia in ARV naïve HIV-1 infected people through differential reduction of plasma levels of filarial antigen specific IgG3, IgG4 and a significant increase in plasma levels of filarial antigen specific IgE could diminish Loa loa mediated immune-regulation. This in effect can result to increase loaisis mediated immunopathology in antiretroviral naive HIV-1 infected people.
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Affiliation(s)
- Ghislain Donald Njambe Priso
- Laboratory of vaccinology/biobanking, CIRCB, Messa, Yaounde, Cameroon.,Department of animal biology and Phisiology, University of Yaounde I, Yaounde, Cameroon
| | - Abel Lissom
- Laboratory of vaccinology/biobanking, CIRCB, Messa, Yaounde, Cameroon.,Department of animal biology and Phisiology, University of Yaounde I, Yaounde, Cameroon
| | - Loveline N Ngu
- Laboratory of vaccinology/biobanking, CIRCB, Messa, Yaounde, Cameroon.,Department of biochemistry, University of Yaounde I, Yaounde, Cameroon
| | - Nadesh N Nji
- Laboratory of vaccinology/biobanking, CIRCB, Messa, Yaounde, Cameroon
| | - Jules Colince Tchadji
- Laboratory of vaccinology/biobanking, CIRCB, Messa, Yaounde, Cameroon.,Department of animal biology and Phisiology, University of Yaounde I, Yaounde, Cameroon
| | - Thibau Flaurant Tchouangueu
- Laboratory of vaccinology/biobanking, CIRCB, Messa, Yaounde, Cameroon.,Department of biochemistry, University of Dschang, Yaounde, Cameroon
| | - Georgia E Ambada
- Laboratory of vaccinology/biobanking, CIRCB, Messa, Yaounde, Cameroon.,Department of animal biology and Phisiology, University of Yaounde I, Yaounde, Cameroon
| | - Carole Stéphanie Sake Ngane
- Laboratory of vaccinology/biobanking, CIRCB, Messa, Yaounde, Cameroon.,Department of Microbiology, University of Yaounde I, Yaounde, Cameroon.,Department of biochemistry, University of Yaounde I, Yaounde, Cameroon
| | - Brigitte Laure Dafeu
- Laboratory of vaccinology/biobanking, CIRCB, Messa, Yaounde, Cameroon.,Department of animal biology and Phisiology, University of Yaounde I, Yaounde, Cameroon
| | - Larissa Djukouo
- Laboratory of vaccinology/biobanking, CIRCB, Messa, Yaounde, Cameroon.,Department of biochemistry, University of Yaounde I, Yaounde, Cameroon
| | - Inès Nyebe
- Laboratory of vaccinology/biobanking, CIRCB, Messa, Yaounde, Cameroon.,Department of Microbiology, University of Yaounde I, Yaounde, Cameroon
| | - Suzanne Magagoum
- Laboratory of vaccinology/biobanking, CIRCB, Messa, Yaounde, Cameroon.,Department of animal biology and Phisiology, University of Yaounde I, Yaounde, Cameroon
| | - Apeh Alfred Ngoh
- Laboratory of vaccinology/biobanking, CIRCB, Messa, Yaounde, Cameroon.,Department of biomedical sciences, University of Dschang, Dschang, Cameroon
| | - Ouambo Fotso Herve
- Laboratory of vaccinology/biobanking, CIRCB, Messa, Yaounde, Cameroon.,Department of medical laboratory sciences, University of Buea, Buea, Cameroon
| | - Rosario Garcia
- CSCB (Centre de santé catholique de Bikop), Bikop, Cameroon
| | - Anna Gutiérrez
- CSCB (Centre de santé catholique de Bikop), Bikop, Cameroon
| | | | - Charles O Esimone
- Department of Pharmaceutical Microbiology & Biotechnology, Nnamdi Azikiwe University, Awka, Nigeria
| | - Flobert Njiokou
- Department of animal biology and Phisiology, University of Yaounde I, Yaounde, Cameroon
| | - Chae Gyu Park
- Laboratory of Immunology, Brain Korea 21 PLUS Project for Medical Science, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Alain Bopda Waffo
- Department of Biological Sciences, College STEM, 1627 Hall Street, Montgomery, AL, 36101, USA.,Center for NanoBiotechnology Research, 1627 Harris Way, Montgomery, AL, 36104, USA
| | - Godwin W Nchinda
- Laboratory of vaccinology/biobanking, CIRCB, Messa, Yaounde, Cameroon.
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Akue JP, Eyang-Assengone ER, Dieki R. Loa loa infection detection using biomarkers: current perspectives. Res Rep Trop Med 2018; 9:43-48. [PMID: 30050354 PMCID: PMC6047611 DOI: 10.2147/rrtm.s132380] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Loa loa is originally a restricted filarial worm from central Africa and some west African countries. However, numerous imported cases are being reported throughout the world due to human movement. Traditionally, its diagnosis is based on identification of microfilariae in the peripheral blood or the passage of the adult worm under the conjunctiva. However, few patients have microfilariae in their peripheral blood, while the majority of infected people are amicrofilaremic (without microfilariae in their blood), despite clinical symptoms suggesting L. loa infection. This situation suggests that diagnoses based on the presence of microfilariae in the blood or the ocular passage of an adult worm, are not sensitive. Therefore, it seems necessary to search for biomarkers to remedy this situation. Furthermore, L. loa is a major obstacle in the control of other filarial worms in areas where these filariae are co-endemic. To develop a diagnostic tool based on a biomarker, several approaches have been considered using antibodies, antigens or nucleic acid detection. However, none of the diagnostic techniques in loiasis based on biomarkers has reached the point of care as have microscopic detection of microfilariae or observation of ocular passage of a worm.
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Affiliation(s)
- Jean Paul Akue
- Department of Parasitology, Centre International of Medical Research of Franceville, Franceville, Gabon,
| | - Elsa-Rush Eyang-Assengone
- Department of Parasitology, Centre International of Medical Research of Franceville, Franceville, Gabon, .,Department of Infectiologie Tropicale, Ecole Doctorale Régionale d'Afrique Centrale, Franceville, Gabon
| | - Roland Dieki
- Department of Parasitology, Centre International of Medical Research of Franceville, Franceville, Gabon,
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Whittaker C, Walker M, Pion SD, Chesnais CB, Boussinesq M, Basáñez MG. The Population Biology and Transmission Dynamics of Loa loa. Trends Parasitol 2018; 34:335-350. [DOI: 10.1016/j.pt.2017.12.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/10/2017] [Accepted: 12/11/2017] [Indexed: 11/27/2022]
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Cano J, Basáñez MG, O'Hanlon SJ, Tekle AH, Wanji S, Zouré HG, Rebollo MP, Pullan RL. Identifying co-endemic areas for major filarial infections in sub-Saharan Africa: seeking synergies and preventing severe adverse events during mass drug administration campaigns. Parasit Vectors 2018; 11:70. [PMID: 29382363 PMCID: PMC5791223 DOI: 10.1186/s13071-018-2655-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 01/16/2018] [Indexed: 02/06/2023] Open
Abstract
Background Onchocerciasis and lymphatic filariasis (LF) are major filarial infections targeted for elimination in most endemic sub-Saharan Africa (SSA) countries by 2020/2025. The current control strategies are built upon community-directed mass administration of ivermectin (CDTI) for onchocerciasis, and ivermectin plus albendazole for LF, with evidence pointing towards the potential for novel drug regimens. When distributing microfilaricides however, considerable care is needed to minimise the risk of severe adverse events (SAEs) in areas that are co-endemic for onchocerciasis or LF and loiasis. This work aims to combine previously published predictive risk maps for onchocerciasis, LF and loiasis to (i) explore the scale of spatial heterogeneity in co-distributions, (ii) delineate target populations for different treatment strategies, and (iii) quantify populations at risk of SAEs across the continent. Methods Geographical co-endemicity of filarial infections prior to the implementation of large-scale mass treatment interventions was analysed by combining a contemporary LF endemicity map with predictive prevalence maps of onchocerciasis and loiasis. Potential treatment strategies were geographically delineated according to the level of co-endemicity and estimated transmission intensity. Results In total, an estimated 251 million people live in areas of LF and/or onchocerciasis transmission in SSA, based on 2015 population estimates. Of these, 96 million live in areas co-endemic for both LF and onchocerciasis, providing opportunities for integrated control programmes, and 83 million live in LF-monoendemic areas potentially targetable for the novel ivermectin-diethylcarbamazine-albendazole (IDA) triple therapy. Only 4% of the at-risk population live in areas co-endemic with high loiasis transmission, representing up to 1.2 million individuals at high risk of experiencing SAEs if treated with ivermectin. In these areas, alternative treatment strategies should be explored, including biannual albendazole monotherapy for LF (1.4 million individuals) and ‘test-and-treat’ strategies (8.7 million individuals) for onchocerciasis. Conclusions These maps are intended to initiate discussion around the potential for tailored treatment strategies, and highlight populations at risk of SAEs. Further work is required to test and refine strategies in programmatic settings, providing the empirical evidence needed to guide efforts towards the 2020/2025 goals and beyond. Electronic supplementary material The online version of this article (10.1186/s13071-018-2655-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jorge Cano
- Department of Disease Control, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
| | - Maria-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, UK
| | - Simon J O'Hanlon
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, UK
| | - Afework H Tekle
- Research Foundation in Tropical Medicine and the Environment, Buea, Cameroon
| | - Samuel Wanji
- Department of Biochemistry and Microbiology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation in Tropical Medicine and the Environment, Buea, Cameroon
| | - Honorat G Zouré
- Former African Programme for Onchocerciasis Control Programme, Ouagadougou, Burkina Faso
| | - Maria P Rebollo
- Expanded Special Programme for Elimination of Neglected Tropical Diseases (ESPEN), Brazzaville, Republic of Congo
| | - Rachel L Pullan
- Department of Disease Control, Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
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Brito M, Paulo R, Van-Dunem P, Martins A, Unnasch TR, Novak RJ, Jacob B, Stanton MC, Molyneux DH, Kelly-Hope LA. Rapid integrated clinical survey to determine prevalence and co-distribution patterns of lymphatic filariasis and onchocerciasis in a Loa loa co-endemic area: The Angolan experience. Parasite Epidemiol Control 2017; 2:71-84. [PMID: 29774284 PMCID: PMC5952692 DOI: 10.1016/j.parepi.2017.05.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/04/2017] [Accepted: 05/06/2017] [Indexed: 01/03/2023] Open
Abstract
The Republic of Angola is a priority country for onchocerciasis and lymphatic filariasis (LF) elimination, however, the co-distribution of the filarial parasite Loa loa (loiasis) is a significant impediment, due to the risk of severe adverse events (SAEs) associated with ivermectin used in mass drug administration (MDA) campaigns. Angola has a high risk loiasis zone identified in Bengo Province where alternative interventions may need to be implemented; however, the presence and geographical overlap of the three filarial infections/diseases are not well defined. Therefore, this study conducted a rapid integrated filarial mapping survey based on readily identifiable clinical conditions of each disease in this risk zone to help determine prevalence and co-distribution patterns in a timely manner with limited resources. In total, 2007 individuals from 29 communities in five provincial municipalities were surveyed. Community prevalence estimates were determined by the rapid assessment procedure for loiasis (RAPLOA) and rapid epidemiological mapping of onchocerciasis (REMO) together with two questions on LF clinical manifestations (presence of lymphoedema, hydrocoele). Overall low levels of endemicity, with different overlapping distributions were found. Loiasis was found in 18 communities with a prevalence of 2.0% (31/1571), which contrasted to previous results defining the area as a high risk zone. Onchocerciasis prevalence was 5.3% (49/922) in eight communities, and LF prevalence was 0.4% for lymphoedema (8/2007) and 2.6% for hydrocoeles (20/761 males) in seven and 12 communities respectively. The clinical mapping survey method helped to highlight that all three filarial infections are present in this zone of Bengo Province. However, the significant difference in loiasis prevalence found between the past and this current survey suggests that further studies including serological and parasitological confirmation are required. This will help determine levels of infection and risk, understand the associations between clinical, serological and parasitological prevalence patterns, and better determine the most appropriate treatment strategies to reach onchocerciasis and LF elimination targets in the loiasis co-endemic areas. Our results also suggest that the utility of the earlier RAPLOA derived maps, based on surveys undertaken over a decade ago, are likely to be invalid given the extent of population movement and environmental change, particularly deforestation, and that fine scale micro-mapping is required to more precisely delineate the interventions required defined by these complex co-endemicities.
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Affiliation(s)
- Miguel Brito
- Centro de Investigacao em Saude de Angola/Health Research Centre of Angola, Caxito, Angola
- Lisbon School of Health Technology, Lisbon, Portugal
| | - Rossely Paulo
- Centro de Investigacao em Saude de Angola/Health Research Centre of Angola, Caxito, Angola
- Centre for Neglected Tropical Diseases, and Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Pedro Van-Dunem
- National Directorate of Public Health, Ministry of Health, Angola
| | - António Martins
- Centro de Investigacao em Saude de Angola/Health Research Centre of Angola, Caxito, Angola
| | - Thomas R Unnasch
- College of Public Health, Department of Global Health, University of South Florida, Florida, USA
| | - Robert J Novak
- College of Public Health, Department of Global Health, University of South Florida, Florida, USA
| | - Benjamin Jacob
- College of Public Health, Department of Global Health, University of South Florida, Florida, USA
| | - Michelle C Stanton
- Centre for Neglected Tropical Diseases, and Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - David H Molyneux
- Centre for Neglected Tropical Diseases, and Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Louise A Kelly-Hope
- Centre for Neglected Tropical Diseases, and Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK
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Pedram B, Pasquetto V, Drame PM, Ji Y, Gonzalez-Moa MJ, Baldwin RK, Nutman TB, Biamonte MA. A novel rapid test for detecting antibody responses to Loa loa infections. PLoS Negl Trop Dis 2017; 11:e0005741. [PMID: 28749939 PMCID: PMC5531435 DOI: 10.1371/journal.pntd.0005741] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 06/23/2017] [Indexed: 01/06/2023] Open
Abstract
Ivermectin-based mass drug administration (MDA) programs have achieved remarkable success towards the elimination of onchocerciasis and lymphatic filariasis. However, their full implementation has been hindered in Central Africa by the occurrence of ivermectin-related severe adverse events (SAEs) in a subset of individuals with high circulating levels of Loa loa microfilariae. Extending MDA to areas with coincident L. loa infection is problematic, and inexpensive point-of-care tests for L. loa are acutely needed. Herein, we present a lateral flow assay (LFA) to identify subjects with a serological response to Ll-SXP-1, a specific and validated marker of L. loa. The test was evaluated on serum samples from patients infected with L. loa (n = 109) and other helminths (n = 204), as well as on uninfected controls (n = 77). When read with the naked eye, the test was 94% sensitive for L. loa infection and was 100% specific when sera from healthy endemic and non-endemic controls or from those with S. stercoralis infections were used as the comparators. When sera of patients with O. volvulus, W. bancrofti, or M. perstans were used as the comparators, the specificity of the LFA was 82%, 87%, and 88%, respectively. A companion smartphone reader allowed measurement of the test line intensities and establishment of cutoff values. With a cutoff of 600 Units, the assay sensitivity decreased to 71%, but the specificity increased to 96% for O. volvulus, 100% for W. bancrofti, and 100% for M. perstans-infected individuals. The LFA may find applications in refining the current maps of L. loa prevalence, which are needed to eliminate onchocerciasis and lymphatic filariasis from the African continent.
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Affiliation(s)
- Bijan Pedram
- Drugs & Diagnostics for Tropical Diseases, San Diego, California, United States of America
| | - Valérie Pasquetto
- Drugs & Diagnostics for Tropical Diseases, San Diego, California, United States of America
| | - Papa M. Drame
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Yongchang Ji
- Drugs & Diagnostics for Tropical Diseases, San Diego, California, United States of America
| | - Maria J. Gonzalez-Moa
- Drugs & Diagnostics for Tropical Diseases, San Diego, California, United States of America
| | | | - Thomas B. Nutman
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Marco A. Biamonte
- Drugs & Diagnostics for Tropical Diseases, San Diego, California, United States of America
- * E-mail:
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Discovery of Specific Antigens That Can Predict Microfilarial Intensity in Loa loa Infection. J Clin Microbiol 2017. [PMID: 28637911 DOI: 10.1128/jcm.00513-17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Antigen-based immunoassays are currently needed for point-of-care quantification of Loa loa microfilariae (mf). Coupling transcriptomic approaches with bioinformatic analysis, we have identified 11 specific putative proteins (coding mRNAs) with potential utility as biomarkers of patent (mf + ) L. loa infection. We successfully developed antigen capture immunoassays to quantify 2 (LOAG_14221 and LOAG_15846) of these proteins in individual plasma/serum samples. Of the 2 quantifiable circulating biomarkers, LOAG_14221 showed the highest degree of specificity, particularly with a monoclonal antibody-based immunoassay. Moreover, the levels of LOAG_14221 in L. loa mf + patients were positively correlated to the mf densities in the corresponding blood samples (r = 0.53 and P = 0.008 for polyclonal assay; r = 0.54 and P = 0.004 for monoclonal assay). Thus, LOAG_14221 is a very promising biomarker that will be exploited in a quantitative point-of-care immunoassay for determination of L. loa mf densities.
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Kelly-Hope L, Paulo R, Thomas B, Brito M, Unnasch TR, Molyneux D. Loa loa vectors Chrysops spp.: perspectives on research, distribution, bionomics, and implications for elimination of lymphatic filariasis and onchocerciasis. Parasit Vectors 2017; 10:172. [PMID: 28381279 PMCID: PMC5382514 DOI: 10.1186/s13071-017-2103-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 03/23/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Loiasis is a filarial disease caused Loa loa. The main vectors are Chrysops silacea and C. dimidiata which are confined to the tropical rainforests of Central and West Africa. Loiasis is a mild disease, but individuals with high microfilaria loads may suffer from severe adverse events if treated with ivermectin during mass drug administration campaigns for the elimination of lymphatic filariasis and onchocerciasis. This poses significant challenges for elimination programmes and alternative interventions are required in L. loa co-endemic areas. The control of Chrysops has not been considered as a viable cost-effective intervention; we reviewed the current knowledge of Chrysops vectors to assess the potential for control as well as identified areas for future research. RESULTS We identified 89 primary published documents on the two main L. loa vectors C. silacea and C dimidiata. These were collated into a database summarising the publication, field and laboratory procedures, species distributions, ecology, habitats and methods of vector control. The majority of articles were from the 1950-1960s. Field studies conducted in Cameroon, Democratic Republic of Congo, Equatorial Guinea, Nigeria and Sudan highlighted that C. silacea is the most important and widespread vector. This species breeds in muddy streams or swampy areas of forests or plantations, descends from forest canopies to feed on humans during the day, is more readily adapted to human dwellings and attracted to wood fires. Main vector targeted measures proposed to impact on L. loa transmission included personal repellents, household screening, indoor residual spraying, community-based environmental management, adulticiding and larviciding. CONCLUSIONS This is the first comprehensive review of the major L. loa vectors for several decades. It highlights key vector transmission characteristics that may be targeted for vector control providing insights into the potential for integrated vector management, with multiple diseases being targeted simultaneously, with shared human and financial resources and multiple impact. Integrated vector management programmes for filarial infections, especially in low transmission areas of onchocerciasis, require innovative approaches and alternative strategies if the elimination targets established by the World Health Organization are to be achieved.
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Affiliation(s)
- Louise Kelly-Hope
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Rossely Paulo
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK.,CISA, Health Research Centre of Angola, Caxito, Angola
| | - Brent Thomas
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Miguel Brito
- CISA, Health Research Centre of Angola, Caxito, Angola.,Lisbon School of Health Technology, Lisbon, Portugal
| | - Thomas R Unnasch
- College of Public Health, Department of Global Health, University of South Florida, Tampa, USA
| | - David Molyneux
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK
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