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Ebai R, Kien CA, Fombad FF, Esofi F, Ouam E, Ntuh AN, Amambo GN, Gandjui VNT, Chunda VC, Nietcho F, Nchang LC, Magha C, Cho JF, Esum ME, Enyong PI, Pfarr K, Hoerauf A, Ritter M, Wanji S. Culicoides Species of the Rain Forest Belt of the Littoral Region of Cameroon: Their Incrimination in the Transmission of Mansonella perstans. Pathogens 2024; 13:146. [PMID: 38392884 PMCID: PMC10892414 DOI: 10.3390/pathogens13020146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/05/2024] [Accepted: 01/30/2024] [Indexed: 02/25/2024] Open
Abstract
Biting midges belonging to the genus Culicoides are tiny stout-shaped hematophagous insects and are thought to transmit the filarial nematode Mansonella perstans. Little is known about the Culicoides fauna in the rain forest belt of the Littoral Region of Cameroon. This study was designed to investigate the diversity, abundance and distribution of Culicoides spp. and their role as the purported vector(s) of M. perstans. Overnight light trap collections and human landing catches (HLCs) revealed eight species of Culicoides with C. grahamii being the most abundant species followed by C. milnei. Four anthropophilic species (C. inornatipennis, C. grahamii, C. fulvithorax and C. milnei) were determined by the HLCs with a higher abundance in the 4-6 p.m. collections. The drop trap technique and Mp419 LAMP assay confirmed C. milnei to be the most efficient vector in enabling the development of the microfilarial stage to the infective larval form of M. perstans. The LAMP assay also revealed that natural transmission of this nematode is fostered by C. milnei and C. grahamii in the wild. In conclusion, C. milnei was shown to be the main vector of M. perstans in the rain forest belt of the Littoral Region of Cameroon.
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Affiliation(s)
- Rene Ebai
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Chi Anizette Kien
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Fanny Fri Fombad
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Frederick Esofi
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Emmanuel Ouam
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Anna Ning Ntuh
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Glory Ngongeh Amambo
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Victor Narcisse Tchamatchoua Gandjui
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Valerine Chawa Chunda
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Franck Nietcho
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Lucy Cho Nchang
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Chefor Magha
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Jerome Fru Cho
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Mathias Eyong Esum
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Peter Ivo Enyong
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
| | - Kenneth Pfarr
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), 53127 Bonn, Germany (A.H.)
- German Centre for Infection Research (DZIF), Partner Site Bonn-Cologne, 53127 Bonn, Germany
| | - Achim Hoerauf
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), 53127 Bonn, Germany (A.H.)
- German Centre for Infection Research (DZIF), Partner Site Bonn-Cologne, 53127 Bonn, Germany
- German-West African Centre for Global Health and Pandemic Prevention (G-WAC), Partner Site Bonn, 53127 Bonn, Germany
| | - Manuel Ritter
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn (UKB), 53127 Bonn, Germany (A.H.)
- German-West African Centre for Global Health and Pandemic Prevention (G-WAC), Partner Site Bonn, 53127 Bonn, Germany
| | - Samuel Wanji
- Parasite and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea P.O. Box 63, Cameroon (C.A.K.); (A.N.N.); (V.N.T.G.); (V.C.C.); (C.M.)
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea P.O. Box 63, Cameroon
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Jobe NB, Huijben S, Paaijmans KP. Non-target effects of chemical malaria vector control on other biological and mechanical infectious disease vectors. Lancet Planet Health 2023; 7:e706-e717. [PMID: 37558351 DOI: 10.1016/s2542-5196(23)00136-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 06/09/2023] [Accepted: 06/17/2023] [Indexed: 08/11/2023]
Abstract
Public health insecticides play a crucial role in malaria control and elimination programmes. Many other arthropods, including mechanical and biological vectors of infectious diseases, have similar indoor feeding or resting behaviours, or both, as malaria mosquitoes, and could be exposed to the same insecticides. In this Personal View, we show that little is known about the insecticide susceptibility status and the extent of exposure to malaria interventions of other arthropod species. We highlight that there is an urgent need to better understand the selection pressure for insecticide resistance in those vectors, to ensure current and future active ingredients remain effective in targeting a broad range of arthropod species, allowing us to prevent and control future outbreaks of infectious diseases other than malaria.
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Affiliation(s)
- Ndey Bassin Jobe
- The Center for Evolution & Medicine, School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Silvie Huijben
- The Center for Evolution & Medicine, School of Life Sciences, Arizona State University, Tempe, AZ, USA; Simon A Levin Mathematical, Computational and Modeling Sciences Center, Arizona State University, Tempe, AZ, USA
| | - Krijn P Paaijmans
- The Center for Evolution & Medicine, School of Life Sciences, Arizona State University, Tempe, AZ, USA; Simon A Levin Mathematical, Computational and Modeling Sciences Center, Arizona State University, Tempe, AZ, USA; The Biodesign Center for Immunotherapy, Vaccines and Virotherapy, Arizona State University, Tempe, AZ, USA; ISGlobal, Barcelona, Spain; Centro de Investigação em Saúde de Manhiça, Maputo, Mozambique.
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Brattig NW, Cheke RA, Garms R. Onchocerciasis (river blindness) - more than a century of research and control. Acta Trop 2021; 218:105677. [PMID: 32857984 DOI: 10.1016/j.actatropica.2020.105677] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 08/06/2020] [Accepted: 08/21/2020] [Indexed: 12/14/2022]
Abstract
This review summarises more than a century of research on onchocerciasis, also known as river blindness, and its control. River blindness is an infection caused by the tissue filaria Onchocerca volvulus affecting the skin, subcutaneous tissue and eyes and leading to blindness in a minority of infected persons. The parasite is transmitted by its intermediate hosts Simulium spp. which breed in rivers. Featured are history and milestones in onchocerciasis research and control, state-of-the-art data on the parasite, its endobacteria Wolbachia, on the vectors, previous and current prevalence of the infection, its diagnostics, the interaction between the parasite and its host, immune responses and the pathology of onchocerciasis. Detailed information is documented on the time course of control programmes in the afflicted countries in Africa and the Americas, a long road from previous programmes to current successes in control of the transmission of this infectious disease. By development, adjustment and optimization of the control measures, transmission by the vector has been interrupted in foci of countries in the Americas, in Uganda, in Sudan and elsewhere, followed by onchocerciasis eliminations. The current state and future perspectives for control, elimination and eradication within the next 20-30 years are described and discussed. This review contributes to a deeper comprehension of this disease by a tissue-dwelling filaria and it will be helpful in efforts to control and eliminate other filarial infections.
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Wanji S, Tayong DB, Ebai R, Opoku V, Kien CA, Ndongmo WPC, Njouendou AJ, Ghani RN, Ritter M, Debrah YA, Layland LE, Enyong PA, Hoerauf A. Update on the biology and ecology of Culicoides species in the South-West region of Cameroon with implications on the transmission of Mansonella perstans. Parasit Vectors 2019; 12:166. [PMID: 30975194 PMCID: PMC6460808 DOI: 10.1186/s13071-019-3432-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Accepted: 04/04/2019] [Indexed: 11/17/2022] Open
Abstract
Background Culicoides (Diptera; Ceratoponidae) are tiny, stout, blood-sucking flies with a near worldwide distribution. When present, they are often considered a biting nuisance but in addition, they are involved in the transmission of pathogens to humans, domestic and wild animals. Data on Culicoides species in the South-West region of Cameroon dates back to the 1950s. Over the decades, ecological transformation due to agriculture and deforestation may have affected the population dynamics of Culicoides and therefore our study provides an update of their bio-ecology in the region. Furthermore, the role of various Culicoides species in the transmission of parasitic filariae of the genus Mansonella remains inconclusive in this region. This study was designed to address these unknown issues and expand on current scientific knowledge. Results Eight species of Culicoides (C. bedfordi, C. inornatipennis, C. fulvithorax, C. grahamii, C. imicola, C. milnei, C. neavei and C. kumbaensis) were collected using light traps and human baits. Culicoides grahamii was the most abundant species, followed closely by C. milnei. Three species (C. milnei, C. grahamii and C. inornatipennis) were common in all observed larval development sites. Only four species (C. inornatipennis, C. fulvithorax, C. grahamii and C. milnei) were collected on humans. Anthropophilic species were more abundant (P < 0.001) in the evening (4–7 pm) when compared to the morning collections (6–9 am). After overnight fly collections using a drop trap with a human microfilaremic donor, C. milnei emerged as the potential host for transmitting Mansonella perstans. Substantial heterogeneity was observed between the trap visiting cycles of the various species (P < 0.001). The biting cycle of the main vector, C. milnei, showed two peaks (10–11 pm and 4–5 am), the highest being 10–11 pm. Conclusions The Culicoides fauna of the South-West region of Cameroon has not changed significantly since the 1950s. Culicoides milnei was demonstrated to be the major vector of M. perstans in this part of Cameroon. It is essentially a nocturnal species which peaks in abundance between 10 and 11 pm. Electronic supplementary material The online version of this article (10.1186/s13071-019-3432-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Samuel Wanji
- Parasite and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon. .,Research Foundation for Tropical Diseases and the Environment (REFOTDE), P.O. Box 474, Buea, Cameroon.
| | - Dizzle Bita Tayong
- Parasite and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation for Tropical Diseases and the Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Rene Ebai
- Parasite and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Vera Opoku
- Kumasi Centre for Collaborative Research (KCCR), Kumasi, Ghana
| | - Chi Anizette Kien
- Parasite and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Winston Patrick Chounna Ndongmo
- Parasite and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation for Tropical Diseases and the Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Abdel Jelil Njouendou
- Parasite and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation for Tropical Diseases and the Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Raymond Nsaidzedze Ghani
- Parasite and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Manuel Ritter
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn, Bonn, Germany
| | - Yaw Alex Debrah
- Kumasi Centre for Collaborative Research (KCCR), Kumasi, Ghana
| | - Laura E Layland
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn, Bonn, Germany.,German Centre for Infection Research (DZIF), Partner Site, Bonn-Cologne, Bonn, Germany
| | - Peter A Enyong
- Parasite and Vector Biology Research Unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, P.O. Box 63, Buea, Cameroon.,Research Foundation for Tropical Diseases and the Environment (REFOTDE), P.O. Box 474, Buea, Cameroon
| | - Achim Hoerauf
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University Hospital Bonn, Bonn, Germany.,German Centre for Infection Research (DZIF), Partner Site, Bonn-Cologne, Bonn, Germany
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Xiang H, Zhang Y, Richardson JS. Importance of Riparian Zone: Effects of Resource Availability at Land-water Interface. ACTA ACUST UNITED AC 2017. [DOI: 10.1515/remc-2016-0001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractRiparian zone provides a variety of resources to organisms, including availability of water and subsidies. Water availability in riparian areas influences species distribution and trophic interaction of terrestrial food webs. Cross-ecosystem subsidies as resource flux of additional energy, nutrients, and materials benefit riparian populations and communities (e.g. plants, spiders, lizards, birds and mammals). However, aquatic ecosystems and riparian zones are prone to anthropogenic disturbances, which change water availability and affect the flux dynamics of cross-system subsidies. Yet, we still lack sufficient empirical studies assessing impacts of disturbances of land use, climate change and invasive species individually and interactively on aquatic and riparian ecosystems through influencing subsidy resource availability. In filling this knowledge gap, we can make more effective efforts to protect and conserve riparian habitats and biodiversity, and maintain riparian ecosystem functioning and services.
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Hadis M, Wilson MD, Cobblah M, Boakye DA. Cytotaxonomic description ofSimulium kaffaense, a new member of theS. damnosumcomplex (Diptera: Simuliidae) from south–western Ethiopia. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2013; 99:267-91. [PMID: 15829136 DOI: 10.1179/136485905x24210] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Although Ethiopia is one of the countries worst affected by human onchocerciasis, the exact taxonomic identity of the blackflies acting as the main vectors in the endemic areas has never been determined. A cytotaxonomic analysis of Simulium damnosum s.l. collected from three endemic sites in south-western Ethiopia has now revealed the existence of the 'Kisiwani' form (a non-anthropophilic cytoform that is common in East Africa) and a newly recognized species, Simulium kaffaense. Simulium kaffaense sp. nov. is differentiated from other members of the S. damnosum complex by six fixed inversions and dozens of 'new' floating inversions. The rearing of egg batches from some of the biting adult females, to larvae or adults, indicated that the human-biting blackflies were all S. kaffaense. As S. kaffaense is not only highly anthropophilic but also, apparently, the only anthropophilic member of the S. damnosum complex present, it is likely to be the main (if not the only) vector of Onchocerca volvulus in the study area. The presence of inversion 1S-1 and a complex inversion possibly involving 1L-3 indicates that S. kaffaense either belongs or is close to the 'Nile' phylogenetic group of S. damnosum s. l. The karyotype frequencies of the inversions in the collections from the three study sites indicate that at least two forms of S. kaffaense, here designated 'Bebeka' and 'Jimma', were caught. The taxonomy and medical importance of S. kaffaense are discussed.
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Affiliation(s)
- M Hadis
- Noguchi Memorial Institute for Medical Research, University of Ghana, P. O. Box LG 581, Legon, Accra, Ghana
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Agbolade OM, Akinboye DO, Olateju TM, Ayanbiyi OA, Kuloyo OO, Fenuga OO. Biting of anthropophilic Culicoides fulvithorax (Diptera: Ceratopogonidae), a vector of Mansonella perstans in Nigeria. THE KOREAN JOURNAL OF PARASITOLOGY 2006; 44:67-72. [PMID: 16514285 PMCID: PMC2532646 DOI: 10.3347/kjp.2006.44.1.67] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Anthropophilic Culicoides were investigated in a rural community endemic for Mansonella perstans in Ijebu North area of western Nigeria between December 2003 and October 2004. Three hundred and fifty-nine adults of Culicoides fulvithorax collected by human bait in the morning were dissected for Mansonella perstans larvae, and 1.95% of infection rate was found. Seasonal abundance of C. fulvithorax was investigated by monthly biting rates, and showed that higher prevalence was observed in rainy season, with peak in September. Culicoides prevalence was positively correlated with rainfall and relative humidity, but not temperature. Human perceptions on the behavior of these biting midges were determined by interviewing 854 self-selected villagers, of which 86.5% of the interviewees confessed having experienced Culicoides bites. Between 76.5 and 99.1% of the various age groups complained body reactions to Culicoides bites. Itching was the most frequent body reaction. No interviewees associated Culicoides with transmission of any parasitic infections. The results showed need to adequately control Culicoides in the community.
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Affiliation(s)
- Olufemi Moses Agbolade
- Parasitology and Medical Entomology Laboratory, Department of Plant Science and Applied Zoology, Olabisi Onabanjo University, Ago-Iwoye, Nigeria.
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Abstract
BACKGROUND Owing to the increase of an immigrant population and of Italian citizens travelling for tourism or on business, it is nowadays possible to observe clinical pictures characteristic of tropical regions, often with indistinct symptoms. One of these is Loa loa infestation, or loiasis, a form of filariasis caused by Loa loa and transmitted by the Chrysops fly. We present the case of a male immigrant from Cameroon. Characteristic symptoms were intense xerosis, mostly of the third inferior part of the legs, intensely pruritic, with numerous lesions from scratching. No benefit was obtained by emollient topics, anti-acarus and systemic antihistamines. METHOD Serum samples and Giemsa, haematoxylin, haematoxylin + Giemsa concentration-on-membrane stains, have evidenced the presence of Loa loa microfilariae. RESULTS A diagnosis for L. loa (loiasis) infestation was made. CONCLUSIONS At the beginning of the migration phenomenon, particularly from Africa, Italian physicians, especially dermatologists, were eagerly looking for 'tropical' diseases; this approach can be defined as 'Salgari's syndrome' from the name of the Italian novelist who, though never travelling out of Italy, had perfectly described environments and habits typical of far away countries. Now, conversely, we have to avoid the opposite approach of considering real tropical diseases as related to social or psychological difficult conditions.
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Affiliation(s)
- A Morrone
- Istituto Dermatologico S. Gallicano (IRCCS), Servizio di Medicina Preventiva delle Migrazioni, del Turismo e di Dermatologia Tropicale, Rome, Italy
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Roberts DM, Irving-Bell RJ. Effect of weather conditions on the flight activity of Nigerian blackflies (Diptera:Simuliidae). MEDICAL AND VETERINARY ENTOMOLOGY 1996; 10:137-144. [PMID: 8744705 DOI: 10.1111/j.1365-2915.1996.tb00719.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A vehicle-mounted net was used to make hourly catches of blackflies at 700-1000 m altitude in the River Assob valley, central Nigeria, on 20 days during the dry season. Pearson Correlation Matrix analysis of the collection data and meteorology showed that the main factors affecting flight activity of each of the four most abundant blackfly species were primarily light intensity and secondly wind velocity, whereas relative humidity was the least important factor. Flight activity showed a negative linear regression against wind, with some activity occurring in wind speeds up to 15 km/h. Distance-weighted least-squares (DWLS) regressions showed little correlation of temperature with activity for Simulium hargreavesi and S.adersi, but S.squamosum and S.vorax had small peaks at 28 degrees C and 31 degrees C, respectively. DWLS regression against light intensity showed an activity peak at 6000 lux, except in Simulium adersi.
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Affiliation(s)
- D M Roberts
- Department of Zoology, University of Jos, Plateau State, Nigeria
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Gebre-Michael T, Gemetchu T. Anthropophilic blackflies (Diptera: Simuliidae) and onchocerciasis transmission in southwest Ethiopia. MEDICAL AND VETERINARY ENTOMOLOGY 1996; 10:44-52. [PMID: 8834742 DOI: 10.1111/j.1365-2915.1996.tb00081.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
From May 1984 to May 1985, the transmission of onchocerciasis by blackflies (Dipteria: Simuliidae) was studied around Gilgel Ghibe and Gojeb rivers in southwest Ethiopia. The predominant anthropophilic species of Simulium at both localities were S. (Edwardsellum) damnosum sensu lato and S. (Lewisellum) ethiopiense. Some S. (Anasolen) dentulosum also landed on human bait at Gilgel Ghibe river. Dissections of S. damnosum from Gilgel Ghibe and Gojeb revealed mean parous rates of 92% (n = 18,291) and 84% (n = 9530), respectively. S. ethiopiense from Gilgel Ghibe and Gojeb showed mean parous rates of 53% (n = 322) and 93% (n = 14), respectively. Of the parous S. damnosum, 1.3% at Gilgel Ghibe and 0.5% at Gojeb harboured infective third-stage larvae (L3) of Onchocerca volvulus (or morphologically indistinguishable from it). Unknown filariae of animal origin, indicative of zoophily, were found in 0.3% and 0.7% of Simulium damnosum complex females from Gilgel Ghibe and Gojeb, respectively. S. ethiopiense harboured developing (L1) larvae only, with 7.7% infection rate in both localities. In contrast, S. dentulosum did not harbour any filaria larvae. The annual infective biting rate (AIBR) and transmission potential (ATP) of the S. damnosum complex at Gilgel Ghibe river were 858 and 5478, respectively. The AIBR and ATP of S. damnosum s.l. at Gojeb river were 519.5 and 1963, respectively. These results emphasize the predominant role of the S. damnosum complex in the transmission of O. volvulus in southwest Ethiopia.
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