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Samuel Wanji - One of the best experts on this subject based on the ideXlab platform.
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Projected number of people with Onchocerciasis-Loiasis co-infection in Africa, 1995 to 2025
Clinical Infectious Diseases, 2020Co-Authors: Natalie V.s. Vinkeles Melchers, Samuel Wanji, Michel Boussinesq, Afework Tekle, Honorat Zouré, Luc E. Coffeng, Belen Pedrique, Sébastien D.s. Pion, Jan H. Remme, Wilma A. StolkAbstract:BACKGROUND: Onchocerciasis elimination through mass drug administration (MDA) is hampered by co-endemicity of Loa loa in Africa, as people with high L. loa microfilariae (mf) density can develop serious adverse events (SAEs) after ivermectin treatment. We assessed the geographical overlap of onchocerciasis and Loiasis prevalence and estimated the number of co-infected individuals at risk of post-ivermectin SAEs in West and Central Africa from 1995 to 2025. METHODS: Focussing on regions with suspected Loiasis transmission in 14 African countries, we overlaid pre-control maps of Loiasis and onchocerciasis prevalence to calculate pre-control prevalence of co-infection by 5x5 km² pixel, distinguishing different categories of L. loa mf intensity. Using statistical and mathematical models, we predicted the prevalence of both infections and co-infection for 2015 and 2025, accounting for the impact of MDA with ivermectin. RESULTS: The number of people infected with onchocerciasis was predicted to decline from almost 19 million in 1995 to 4 million in 2025. Of these, 137,000 people were estimated to also have L. loa hypermicrofilaraemia (≥20,000 L. loa mf/mL) in 1995, declining to 31,000 in 2025. In 2025, 92.8% of co-infected cases with Loiasis hypermicrofilaraemia are predicted to live in hypoendemic areas currently not targeted for MDA. CONCLUSIONS: Loiasis co-infection is a major concern for onchocerciasis elimination in Africa. We predict that under current strategies, at least 31,000 co-infected people will still require treatment for onchocerciasis in 2025 while being at risk of SAEs, justifying continued efforts in research and development for safer drugs and control strategies.
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Projected Number of People With Onchocerciasis-Loiasis Coinfection in Africa, 1995 to 2025
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2019Co-Authors: Natalie V S Vinkeles Melchers, Samuel Wanji, Honorat G. M. Zouré, Afework H. Tekle, Jan H. F. Remme, Michel Boussinesq, Sébastien D. S. Pion, Luc E. Coffeng, Belen Pedrique, Wilma A. StolkAbstract:BACKGROUND: Onchocerciasis elimination through mass drug administration (MDA) is hampered by co-endemicity of Loa loa in Africa, as people with high L. loa microfilariae (mf) density can develop serious adverse events (SAEs) after ivermectin treatment. We assessed the geographical overlap of onchocerciasis and Loiasis prevalence and estimated the number of co-infected individuals at risk of post-ivermectin SAEs in West and Central Africa from 1995 to 2025. METHODS: Focussing on regions with suspected Loiasis transmission in 14 African countries, we overlaid pre-control maps of Loiasis and onchocerciasis prevalence to calculate pre-control prevalence of co-infection by 5x5 km² pixel, distinguishing different categories of L. loa mf intensity. Using statistical and mathematical models, we predicted the prevalence of both infections and co-infection for 2015 and 2025, accounting for the impact of MDA with ivermectin. RESULTS: The number of people infected with onchocerciasis was predicted to decline from almost 19 million in 1995 to 4 million in 2025. Of these, 137,000 people were estimated to also have L. loa hypermicrofilaraemia (≥20,000 L. loa mf/mL) in 1995, declining to 31,000 in 2025. In 2025, 92.8% of co-infected cases with Loiasis hypermicrofilaraemia are predicted to live in hypoendemic areas currently not targeted for MDA. CONCLUSIONS: Loiasis co-infection is a major concern for onchocerciasis elimination in Africa. We predict that under current strategies, at least 31,000 co-infected people will still require treatment for onchocerciasis in 2025 while being at risk of SAEs, justifying continued efforts in research and development for safer drugs and control strategies.
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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 neglected tropical diseases, 2018Co-Authors: Samuel Wanji, Abdel Jelil Njouendou, Winston Patrick Chounna Ndongmo, Fanny Fri Fombad, Jonas A. Kengne-ouafo, Yolande Flore Longang Tchounkeu, Benjamin G. Koudou, Moses J. Bockarie, Grace Fobi, Jean Baptiste RoungouAbstract: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.
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Identifying co-endemic areas for major filarial infections in sub-Saharan Africa: seeking synergies and preventing severe adverse events during mass drug administration campaigns
Parasites & Vectors, 2018Co-Authors: Jorge Cano, Samuel Wanji, Afework H. Tekle, María-gloria Basáñez, Simon O’hanlon, Honorat Zouré, Maria P. Rebollo, Rachel L. PullanAbstract: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.
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Identification and characterization of Loa loa antigens responsible for cross-reactivity with rapid diagnostic tests for lymphatic filariasis
2018Co-Authors: Marla I. Hertz, Samuel Wanji, Hugues Nana-djeunga, Joseph Kamgno, Abdel Jelil Njouendou, Valerine Chawa Chunda, Amy Rush, Peter U. Fischer, Gary J. Weil, Philip J. BudgeAbstract:The Global Program to Eliminate Lymphatic Filariasis (LF) relies on rapid diagnostic tests (RDTs) to determine where annual mass drug administration for LF is required and when it can be stopped. These tests detect a Wuchereria bancrofti glycoprotein in the blood of infected persons via a carbohydrate moiety recognized by the monoclonal antibodies AD12 and DH6.5. Loiasis cross-reactivity with LF RDTs has recently been recognized as a serious obstacle to LF elimination in Loiasis-endemic areas. To better understand the nature of this cross-reactivity, we used the DH6.5 antibody to immunoaffinity purify Loa loa antigens from the sera of individuals with a positive RDT due to Loiasis. Immunoblot analysis revealed many circulating AD12/DH6.5-reactive antigens, and proteomic analysis identified multiple L. loa proteins in LF RDT-positive Loiasis sera. These included both secreted and somatic proteins, suggesting that they may be released by dying L. loa adult worms and/or microfilariae. Unlike the single high molecular weight W. bancrofti circulating filarial antigen that is reliably present in the blood of persons with bancroftian filariasis, reactive L. loa antigens appeared to be only transiently present in the blood of a subset of persons with Loiasis. These key differences between the circulating antigens of W. bancrofti and L. loa can be used to differentiate positive results generated by both species and may lead to improved diagnostic tests for LF and Loiasis.
Olivier Bouchaud - One of the best experts on this subject based on the ideXlab platform.
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Imported Loiasis in France: a retrospective analysis of 167 cases with comparison between sub-Saharan and non sub-Saharan African patients.
BMC infectious diseases, 2020Co-Authors: Olivier Bouchaud, Sophie Matheron, Anne Loarec, Jean Dupouy Camet, Patrice Bourée, N. Godineau, Isabelle Poilane, Johann Cailhol, Eric CaumesAbstract:Imported Loiasis is a rare cause of consultation at the return of stay in central Africa, which often poses difficult diagnostic and therapeutic questions to practitioners especially those who are unaccustomed to tropical medicine. These difficulties can lead to risks for the patients especially if inappropriate treatment is given. Large series of imported Loiasis are scarce. We retrospectively studied the data including outcome in patients diagnosed with imported Loiasis between 1993 and 2013 in the Paris area on the basis of a parasitological diagnosis (microfilaremia > 1/ml and/or serologic tests). We compared sub-Saharan and non sub-Saharan African patients. Of the 177 identified cases, 167 could be analysed. Sex ratio was 1, mean age 41 years and 83% were sub-Saharan Africans. Cameroon was the main country of exposure (62%). Incubation time may be long (up to 18 months). Of the 167 cases, 57% presented with characteristic symptoms (Calabar swellings, creeping dermatitis, eyeworm) whereas 43% were diagnosed fortuitously. Microfilaremia was evidenced in 105 patients (63%), and specific antibodies in 53%. Compared to sub-Saharan Africans, other patients were presenting less frequently with eyeworm migration and microfilaremia whereas they had higher eosinophilia and positive serology. Prevalence of Calabar swellings was not significantly different between the two groups. Cure rates were 52% with ivermectin alone, and 77% with ivermectin followed by diethylcarbamazine. No severe adverse event was reported. Presentation of imported Loiasis varies according to ethnicity. A systematic screening should be recommended in patients with potential exposure in endemic country. Treatment with ivermectin followed by diethylcarbamazine could be a valuable option.
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Imported Loiasis in France: a retrospective analysis of 167 cases with comparison between sub-Saharan and non sub-Saharan African patients
BMC Infectious Diseases, 2020Co-Authors: Olivier Bouchaud, Sophie Matheron, Anne Loarec, Patrice Bourée, N. Godineau, Isabelle Poilane, Johann Cailhol, Jean Dupouy Camet, Eric CaumesAbstract:Background: Imported Loiasis is a rare cause of consultation at the return of stay in central Africa, which often poses difficult diagnostic and therapeutic questions to practitioners especially those who are unaccustomed to tropical medicine. These difficulties can lead to risks for the patients especially if inappropriate treatment is given. Large series of imported Loiasis are scarce. Methods: We retrospectively studied the data including outcome in patients diagnosed with imported Loiasis between 1993 and 2013 in the Paris area on the basis of a parasitological diagnosis (microfilaremia > 1/ml and/or serologic tests). We compared sub-Saharan and non sub-Saharan African patients. Results: Of the 177 identified cases, 167 could be analysed. Sex ratio was 1, mean age 41 years and 83% were sub-Saharan Africans. Cameroon was the main country of exposure (62%). Incubation time may be long (up to 18 months). Of the 167 cases, 57% presented with characteristic symptoms (Calabar swellings, creeping dermatitis, eyeworm) whereas 43% were diagnosed fortuitously. Microfilaremia was evidenced in 105 patients (63%), and specific antibodies in 53%. Compared to sub-Saharan Africans, other patients were presenting less frequently with eyeworm migration and microfilaremia whereas they had higher eosinophilia and positive serology. Prevalence of Calabar swellings was not significantly different between the two groups. Cure rates were 52% with ivermectin alone, and 77% with ivermectin followed by diethylcarbamazine. No severe adverse event was reported. Conclusions: Presentation of imported Loiasis varies according to ethnicity. A systematic screening should be recommended in patients with potential exposure in endemic country. Treatment with ivermectin followed by diethylcarbamazine could be a valuable option.
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Comparison of different drug regimens for the treatment of Loiasis—A TropNet retrospective study
PLoS neglected tropical diseases, 2018Co-Authors: Federico Gobbi, Emmanuel Bottieau, Olivier Bouchaud, Dora Buonfrate, Fernando Salvador, Gerardo Rojo-marcos, Paola Rodari, Jan Clerinx, Begoña Treviño, Juan Paulo Herrera-ÁvilaAbstract: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.
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comparison of different drug regimens for the treatment of Loiasis a tropnet retrospective study
PLOS Neglected Tropical Diseases, 2018Co-Authors: Federico Gobbi, Emmanuel Bottieau, Olivier Bouchaud, Dora Buonfrate, Fernando Salvador, Paola Rodari, Jan Clerinx, Begoña Treviño, Gerardo Rojomarcos, Juan Paulo HerreraavilaAbstract: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.
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Characteristics of the 238 patients with Loiasis.
2018Co-Authors: Federico Gobbi, Emmanuel Bottieau, Olivier Bouchaud, Dora Buonfrate, Fernando Salvador, Gerardo Rojo-marcos, Paola Rodari, Jan Clerinx, Begoña Treviño, Juan Paulo Herrera-ÁvilaAbstract:Characteristics of the 238 patients with Loiasis.
Eric Caumes - One of the best experts on this subject based on the ideXlab platform.
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Imported Loiasis in France: a retrospective analysis of 167 cases with comparison between sub-Saharan and non sub-Saharan African patients.
BMC infectious diseases, 2020Co-Authors: Olivier Bouchaud, Sophie Matheron, Anne Loarec, Jean Dupouy Camet, Patrice Bourée, N. Godineau, Isabelle Poilane, Johann Cailhol, Eric CaumesAbstract:Imported Loiasis is a rare cause of consultation at the return of stay in central Africa, which often poses difficult diagnostic and therapeutic questions to practitioners especially those who are unaccustomed to tropical medicine. These difficulties can lead to risks for the patients especially if inappropriate treatment is given. Large series of imported Loiasis are scarce. We retrospectively studied the data including outcome in patients diagnosed with imported Loiasis between 1993 and 2013 in the Paris area on the basis of a parasitological diagnosis (microfilaremia > 1/ml and/or serologic tests). We compared sub-Saharan and non sub-Saharan African patients. Of the 177 identified cases, 167 could be analysed. Sex ratio was 1, mean age 41 years and 83% were sub-Saharan Africans. Cameroon was the main country of exposure (62%). Incubation time may be long (up to 18 months). Of the 167 cases, 57% presented with characteristic symptoms (Calabar swellings, creeping dermatitis, eyeworm) whereas 43% were diagnosed fortuitously. Microfilaremia was evidenced in 105 patients (63%), and specific antibodies in 53%. Compared to sub-Saharan Africans, other patients were presenting less frequently with eyeworm migration and microfilaremia whereas they had higher eosinophilia and positive serology. Prevalence of Calabar swellings was not significantly different between the two groups. Cure rates were 52% with ivermectin alone, and 77% with ivermectin followed by diethylcarbamazine. No severe adverse event was reported. Presentation of imported Loiasis varies according to ethnicity. A systematic screening should be recommended in patients with potential exposure in endemic country. Treatment with ivermectin followed by diethylcarbamazine could be a valuable option.
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Imported Loiasis in France: a retrospective analysis of 167 cases with comparison between sub-Saharan and non sub-Saharan African patients
BMC Infectious Diseases, 2020Co-Authors: Olivier Bouchaud, Sophie Matheron, Anne Loarec, Patrice Bourée, N. Godineau, Isabelle Poilane, Johann Cailhol, Jean Dupouy Camet, Eric CaumesAbstract:Background: Imported Loiasis is a rare cause of consultation at the return of stay in central Africa, which often poses difficult diagnostic and therapeutic questions to practitioners especially those who are unaccustomed to tropical medicine. These difficulties can lead to risks for the patients especially if inappropriate treatment is given. Large series of imported Loiasis are scarce. Methods: We retrospectively studied the data including outcome in patients diagnosed with imported Loiasis between 1993 and 2013 in the Paris area on the basis of a parasitological diagnosis (microfilaremia > 1/ml and/or serologic tests). We compared sub-Saharan and non sub-Saharan African patients. Results: Of the 177 identified cases, 167 could be analysed. Sex ratio was 1, mean age 41 years and 83% were sub-Saharan Africans. Cameroon was the main country of exposure (62%). Incubation time may be long (up to 18 months). Of the 167 cases, 57% presented with characteristic symptoms (Calabar swellings, creeping dermatitis, eyeworm) whereas 43% were diagnosed fortuitously. Microfilaremia was evidenced in 105 patients (63%), and specific antibodies in 53%. Compared to sub-Saharan Africans, other patients were presenting less frequently with eyeworm migration and microfilaremia whereas they had higher eosinophilia and positive serology. Prevalence of Calabar swellings was not significantly different between the two groups. Cure rates were 52% with ivermectin alone, and 77% with ivermectin followed by diethylcarbamazine. No severe adverse event was reported. Conclusions: Presentation of imported Loiasis varies according to ethnicity. A systematic screening should be recommended in patients with potential exposure in endemic country. Treatment with ivermectin followed by diethylcarbamazine could be a valuable option.
Federico Gobbi - One of the best experts on this subject based on the ideXlab platform.
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Performance of two serodiagnostic tests for Loiasis in a Non-Endemic area
PLoS Neglected Tropical Diseases, 2020Co-Authors: Federico Gobbi, Michel Boussinesq, Dora Buonfrate, Paola Rodari, Sébastien D.s. Pion, Cédric Chesnais, Ronaldo Silva, Lucia Moro, Francesca Tamarozzi, Marco BiamonteAbstract:Loiasis, caused by the filarial nematode Loa loa, is endemic in Central and West Africa where about 10 million people are infected. There is a scarcity of convenient, commercial diagnostics for L. loa. Microscopy requires trained personnel and has low sensitivity, while the serodiagnosis is currently not standardized. Individual case management is also important in non-endemic countries to treat migrants, expatriates and tourists. We retrospectively compared the performance of a Loa Antibody Rapid Test (RDT) and a commercial ELISA pan-filarial test on 170 patients, 65 with Loiasis [8 with eyeworm, 29 with positive microfilaremia, 28 with neither microfilaremia nor history of eyeworm but eosinophilia and history of Calabar swelling (probable Loiasis)], 95 with other common parasitic infections and no previous exposure to L. loa (37 with M. perstans, 1 with Brugia sp., 18 with strongyloidiasis, 20 with schistosomiasis, 5 with hookworm, 4 with Ascaris lumbricoides infection, 10 with hyper-reactive malarial splenomegaly), and 10 uninfected controls. The sensitivity of the RDT and of the ELISA were 93.8% (61/65) and 90.8% (59/65), respectively. For the RDT, most of the cross-reactions were observed in patients with M. perstans: 7/37 (18.9%), followed by 1/10 (10%) with hyper-reactive malarial splenomegaly and 1/20 (5%) with schistosomiasis. None of the 27 subjects infected with intestinal nematodes was found positive at this test. The ELISA is meant to be a pan-filarial assay, and reacted extensively with cases of M. perstans (95%), as expected, and also in 11/18 (61.1%) patients with strongyloidiasis and in 3/5 (60%) with hookworm infection. The RDT and the ELISA are both highly sensitive for the diagnosis of Loiasis. The main difference lies in the extent of cross-reactivity with other parasites. Considering that the RDT is specifically meant for Loa loa infection, and its high sensitivity, this test could be a useful tool for the diagnosis of occult Loiasis.
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Efficacy of High-Dose Albendazole With Ivermectin for Treating Imported Loiasis, Italy
Emerging infectious diseases, 2019Co-Authors: Federico Gobbi, Andrea Angheben, Dora Buonfrate, Francesca Tamarozzi, Monica Degani, Zeno BisoffiAbstract:We describe the outcomes of 16 cases of imported Loiasis in Italy. Patients had microfilaremia
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Comparison of different drug regimens for the treatment of Loiasis—A TropNet retrospective study
PLoS neglected tropical diseases, 2018Co-Authors: Federico Gobbi, Emmanuel Bottieau, Olivier Bouchaud, Dora Buonfrate, Fernando Salvador, Gerardo Rojo-marcos, Paola Rodari, Jan Clerinx, Begoña Treviño, Juan Paulo Herrera-ÁvilaAbstract: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.
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comparison of different drug regimens for the treatment of Loiasis a tropnet retrospective study
PLOS Neglected Tropical Diseases, 2018Co-Authors: Federico Gobbi, Emmanuel Bottieau, Olivier Bouchaud, Dora Buonfrate, Fernando Salvador, Paola Rodari, Jan Clerinx, Begoña Treviño, Gerardo Rojomarcos, Juan Paulo HerreraavilaAbstract: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.
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Characteristics of the 238 patients with Loiasis.
2018Co-Authors: Federico Gobbi, Emmanuel Bottieau, Olivier Bouchaud, Dora Buonfrate, Fernando Salvador, Gerardo Rojo-marcos, Paola Rodari, Jan Clerinx, Begoña Treviño, Juan Paulo Herrera-ÁvilaAbstract:Characteristics of the 238 patients with Loiasis.
Michel Boussinesq - One of the best experts on this subject based on the ideXlab platform.
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Performance of two serodiagnostic tests for Loiasis in a Non-Endemic area
PLoS Neglected Tropical Diseases, 2020Co-Authors: Federico Gobbi, Michel Boussinesq, Dora Buonfrate, Paola Rodari, Sébastien D.s. Pion, Cédric Chesnais, Ronaldo Silva, Lucia Moro, Francesca Tamarozzi, Marco BiamonteAbstract:Loiasis, caused by the filarial nematode Loa loa, is endemic in Central and West Africa where about 10 million people are infected. There is a scarcity of convenient, commercial diagnostics for L. loa. Microscopy requires trained personnel and has low sensitivity, while the serodiagnosis is currently not standardized. Individual case management is also important in non-endemic countries to treat migrants, expatriates and tourists. We retrospectively compared the performance of a Loa Antibody Rapid Test (RDT) and a commercial ELISA pan-filarial test on 170 patients, 65 with Loiasis [8 with eyeworm, 29 with positive microfilaremia, 28 with neither microfilaremia nor history of eyeworm but eosinophilia and history of Calabar swelling (probable Loiasis)], 95 with other common parasitic infections and no previous exposure to L. loa (37 with M. perstans, 1 with Brugia sp., 18 with strongyloidiasis, 20 with schistosomiasis, 5 with hookworm, 4 with Ascaris lumbricoides infection, 10 with hyper-reactive malarial splenomegaly), and 10 uninfected controls. The sensitivity of the RDT and of the ELISA were 93.8% (61/65) and 90.8% (59/65), respectively. For the RDT, most of the cross-reactions were observed in patients with M. perstans: 7/37 (18.9%), followed by 1/10 (10%) with hyper-reactive malarial splenomegaly and 1/20 (5%) with schistosomiasis. None of the 27 subjects infected with intestinal nematodes was found positive at this test. The ELISA is meant to be a pan-filarial assay, and reacted extensively with cases of M. perstans (95%), as expected, and also in 11/18 (61.1%) patients with strongyloidiasis and in 3/5 (60%) with hookworm infection. The RDT and the ELISA are both highly sensitive for the diagnosis of Loiasis. The main difference lies in the extent of cross-reactivity with other parasites. Considering that the RDT is specifically meant for Loa loa infection, and its high sensitivity, this test could be a useful tool for the diagnosis of occult Loiasis.
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Projected number of people with Onchocerciasis-Loiasis co-infection in Africa, 1995 to 2025
Clinical Infectious Diseases, 2020Co-Authors: Natalie V.s. Vinkeles Melchers, Samuel Wanji, Michel Boussinesq, Afework Tekle, Honorat Zouré, Luc E. Coffeng, Belen Pedrique, Sébastien D.s. Pion, Jan H. Remme, Wilma A. StolkAbstract:BACKGROUND: Onchocerciasis elimination through mass drug administration (MDA) is hampered by co-endemicity of Loa loa in Africa, as people with high L. loa microfilariae (mf) density can develop serious adverse events (SAEs) after ivermectin treatment. We assessed the geographical overlap of onchocerciasis and Loiasis prevalence and estimated the number of co-infected individuals at risk of post-ivermectin SAEs in West and Central Africa from 1995 to 2025. METHODS: Focussing on regions with suspected Loiasis transmission in 14 African countries, we overlaid pre-control maps of Loiasis and onchocerciasis prevalence to calculate pre-control prevalence of co-infection by 5x5 km² pixel, distinguishing different categories of L. loa mf intensity. Using statistical and mathematical models, we predicted the prevalence of both infections and co-infection for 2015 and 2025, accounting for the impact of MDA with ivermectin. RESULTS: The number of people infected with onchocerciasis was predicted to decline from almost 19 million in 1995 to 4 million in 2025. Of these, 137,000 people were estimated to also have L. loa hypermicrofilaraemia (≥20,000 L. loa mf/mL) in 1995, declining to 31,000 in 2025. In 2025, 92.8% of co-infected cases with Loiasis hypermicrofilaraemia are predicted to live in hypoendemic areas currently not targeted for MDA. CONCLUSIONS: Loiasis co-infection is a major concern for onchocerciasis elimination in Africa. We predict that under current strategies, at least 31,000 co-infected people will still require treatment for onchocerciasis in 2025 while being at risk of SAEs, justifying continued efforts in research and development for safer drugs and control strategies.
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Atypical Clinical Manifestations of Loiasis and Their Relevance for Endemic Populations
Open forum infectious diseases, 2019Co-Authors: Kevin G Buell, Charles Whittaker, Cédric B. Chesnais, Paul D Jewell, Sébastien D. S. Pion, Martin Walker, María-gloria Basáñez, Michel BoussinesqAbstract:Background: Loiasis is mostly considered a relatively benign infection when compared with other filarial and parasitic diseases, with Calabar swellings and eyeworm being the most common signs. Yet, there are numerous reports in the literature of more serious sequelae. Establishing the relationship between infection and disease is a crucial first step toward estimating the burden of Loiasis. Methods: We conducted a systematic review of case reports containing 329 individuals and detailing clinical manifestations of Loiasis with a focus on nonclassical, atypical presentations. Results: Results indicate a high proportion (47%) of atypical presentations in the case reports identified, encompassing a wide range of cardiac, respiratory, gastrointestinal, renal, neurological, ophthalmological, and dermatological pathologies. Individuals with high microfilarial densities and residing in an endemic country were at greater risk of suffering from atypical manifestations. Conclusions: Our findings have important implications for understanding the clinical spectrum of conditions associated with Loa loa infection, which extends well beyond the classical eyeworm and Calabar swellings. As case reports may overestimate the true rate of atypical manifestations in endemic populations, large-scale, longitudinal clinico-epidemiological studies will be required to refine our estimates and demonstrate causality between Loiasis and the breadth of clinical manifestations reported. Even if the rates of atypical presentations were found to be lower, given that residents of Loiasis-endemic areas are both numerous and the group most at risk of severe atypical manifestations, our conclusions support the recognition of Loiasis as a significant public health burden across Central Africa.
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Projected Number of People With Onchocerciasis-Loiasis Coinfection in Africa, 1995 to 2025
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2019Co-Authors: Natalie V S Vinkeles Melchers, Samuel Wanji, Honorat G. M. Zouré, Afework H. Tekle, Jan H. F. Remme, Michel Boussinesq, Sébastien D. S. Pion, Luc E. Coffeng, Belen Pedrique, Wilma A. StolkAbstract:BACKGROUND: Onchocerciasis elimination through mass drug administration (MDA) is hampered by co-endemicity of Loa loa in Africa, as people with high L. loa microfilariae (mf) density can develop serious adverse events (SAEs) after ivermectin treatment. We assessed the geographical overlap of onchocerciasis and Loiasis prevalence and estimated the number of co-infected individuals at risk of post-ivermectin SAEs in West and Central Africa from 1995 to 2025. METHODS: Focussing on regions with suspected Loiasis transmission in 14 African countries, we overlaid pre-control maps of Loiasis and onchocerciasis prevalence to calculate pre-control prevalence of co-infection by 5x5 km² pixel, distinguishing different categories of L. loa mf intensity. Using statistical and mathematical models, we predicted the prevalence of both infections and co-infection for 2015 and 2025, accounting for the impact of MDA with ivermectin. RESULTS: The number of people infected with onchocerciasis was predicted to decline from almost 19 million in 1995 to 4 million in 2025. Of these, 137,000 people were estimated to also have L. loa hypermicrofilaraemia (≥20,000 L. loa mf/mL) in 1995, declining to 31,000 in 2025. In 2025, 92.8% of co-infected cases with Loiasis hypermicrofilaraemia are predicted to live in hypoendemic areas currently not targeted for MDA. CONCLUSIONS: Loiasis co-infection is a major concern for onchocerciasis elimination in Africa. We predict that under current strategies, at least 31,000 co-infected people will still require treatment for onchocerciasis in 2025 while being at risk of SAEs, justifying continued efforts in research and development for safer drugs and control strategies.
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Helminthic Diseases: Onchocerciasis and Loiasis
International Encyclopedia of Public Health, 2017Co-Authors: Jan H. F. Remme, Boakye A. Boatin, Michel BoussinesqAbstract:Onchocerciasis and Loiasis are caused by infection with filarial worms. Severe skin and eye lesions, and blindness are found in onchocerciasis, and the disease is an important public health problem in endemic areas. Loiasis causes Calabar swelling and ‘eye worm,’ whose public health significance is yet to be clarified. Vector control and ivermectin treatment have been used to successfully control or eliminate onchocerciasis, but the risk of severe adverse reactions impedes ivermectin distribution in areas with Loiasis. Research has played a key role in optimizing onchocerciasis control. Onchocerciasis is being progressively eliminated and with a macrofilaricide its eradication could be a reality.
