1
|
Megersa B, Hussein B, Shemsu J, Kassahun R, Merera O, Moje N, Edao BM, Waktole H, Ashenafi H, Ayana D. Trematode infection in ruminants and diversity of snail hosts across three agro-ecological zones in Ethiopia. BMC Vet Res 2024; 20:197. [PMID: 38741097 DOI: 10.1186/s12917-024-04049-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Accepted: 04/30/2024] [Indexed: 05/16/2024] Open
Abstract
The occurrence of trematodes among ruminants and their snail vectors is a major concern across various agro-ecological regions of Ethiopia. Trematodes pose significant threats to animals, causing considerable economic losses and impacting public health. In this study, we have investigated 784 ruminant fecal samples, and 520 abattoir samples, alongside the collection and identification of snail vectors from various agro-ecological regions. Fecal examinations revealed Fasciola, Paramphistomum and Schistosoma species infected 20.5% (95% CI: 17.6, 23.8), 11.7% (95% CI: 9.6, 14.2), and 6.3% (95% CI: 4.1, 9.1) of the animals, respectively. The overall prevalence of trematodes among ruminants was 28.8% (95% CI: 25.7, 32.1%), with 6.0% (95% CI: 4.3, 7.7) showing mixed infections. Fasciola was more prevalent in Asela (26%) compared to Batu (19%) and Hawassa (11.5%), while a higher proportion of animals in Batu were infected with Paramphistomum. Schistosoma eggs were detected only in Batu (12.5%), but not in other areas. Sheep and cattle exhibited higher infection rates with Fasciola, Paramphistoma, and Schistosoma compared to goats. Significant associations were observed between trematode infections and risk factors including agro-ecology, animal species, body condition score, and deworming practices. About 20.8% and 22.7% of the slaughtered animals harbored Fasciola and Paramphistomum flukes, respectively, with a higher prevalence in Asela and Hawassa abattoirs compared to Batu abattoir. Additionally, a total of 278 snails were collected from the study areas and identified as lymnae natalensis, lymnae trancatula, Biomphalaria pffiferi, Biomphlaria sudanica, and Bulinus globosus. In conclusion, the study highlights the widespread occurrence of trematode infections, emphasizing the need for feasible control measures to mitigate their economic and public health impacts.
Collapse
Affiliation(s)
- Bekele Megersa
- College of Veterinary Medicine and Agriculture, Addis Ababa University, Bishoftu, Ethiopia.
| | - Bilisuma Hussein
- College of Veterinary Medicine, Hawassa University, Hawassa, Ethiopia
| | - Jemila Shemsu
- College of Veterinary Medicine and Agriculture, Addis Ababa University, Bishoftu, Ethiopia
| | - Redeat Kassahun
- College of Veterinary Medicine and Agriculture, Addis Ababa University, Bishoftu, Ethiopia
| | - Olana Merera
- College of Veterinary Medicine and Agriculture, Addis Ababa University, Bishoftu, Ethiopia
| | - Nebyou Moje
- College of Veterinary Medicine and Agriculture, Addis Ababa University, Bishoftu, Ethiopia
| | - Bedaso Mammo Edao
- College of Veterinary Medicine and Agriculture, Addis Ababa University, Bishoftu, Ethiopia
- Department of Pathobiology, University of Illinois, Champaign, USA
| | - Hika Waktole
- College of Veterinary Medicine and Agriculture, Addis Ababa University, Bishoftu, Ethiopia
| | - Hagos Ashenafi
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis, Ababa, Ethiopia
| | - Dinka Ayana
- College of Veterinary Medicine and Agriculture, Addis Ababa University, Bishoftu, Ethiopia
| |
Collapse
|
2
|
Ratnadass A, Martin T. Crop protection practices and risks associated with infectious tropical parasitic diseases. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 823:153633. [PMID: 35124028 DOI: 10.1016/j.scitotenv.2022.153633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 01/28/2022] [Accepted: 01/29/2022] [Indexed: 06/14/2023]
Abstract
Two recent literature reviews have shown that: i) agroecological crop protection (ACP) practices generally reduce risks of viral zoonoses, unlike conventional (agrochemical-based) practices which tend to increase them; ii) substitution-based crop protection (CP) practices (mainly biocontrol-based) could result in fewer health risks from bacterial infectious diseases. Here, we present an analysis of the scientific literature to determine to what extent the conclusions regarding viruses or bacteria can be extended to infectious diseases caused by protozoan or helminthic parasites. This analysis of cases of both vector-transmitted and water- or food-borne parasitic diseases, shows, in terms of reduction of health risks: i) an overall negative effect arising from the use of synthetic plant protection products; ii) the relevance of substitution CP practices not strictly under the ACP banner. On the other hand, the public and veterinary health issue of antiparasitic resistance is not affected by CP practices. The positive effects at the large spatio-temporal scales of ACP approaches remain valid, although to a slightly lesser extent than for bacterial diseases and viral zoonoses, in particular through biodiversity conservation which fosters natural regulations and control, preventing the undesirable effects of synthetic pesticides.
Collapse
Affiliation(s)
- Alain Ratnadass
- CIRAD, UPR HortSys, F-97455 Saint-Pierre, Réunion, France; HortSys, Univ Montpellier, CIRAD, Montpellier, France.
| | - Thibaud Martin
- HortSys, Univ Montpellier, CIRAD, Montpellier, France; CIRAD, UPR HortSys, Abidjan, Côte d'Ivoire
| |
Collapse
|
3
|
Mahmoud MM, Younes AA, El-Sherif HA, Gawish FA, Habib MR, Kamel M. Predicting the habitat suitability of Schistosoma intermediate host Bulinus truncatus, its predatory aquatic insect Odonata nymph, and the associated aquatic plant Ceratophyllum demersum using MaxEnt. Parasitol Res 2022; 121:205-216. [PMID: 34981215 DOI: 10.1007/s00436-021-07392-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Accepted: 11/19/2021] [Indexed: 11/30/2022]
Abstract
Schistosomiasis is one of the most important parasitic diseases in tropical and subtropical areas. Its prevalence is associated with the distribution of freshwater snails, which are their intermediate hosts. Thus, control of freshwater snails is the solution to reduce the transmission of this disease. This will be achieved by understanding the relationship between the snails and their habitats including natural enemies and associated aquatic plants as well as the factors affecting their distribution. In this study, Maximum Entropy model (MaxEnt) was used for mapping and predicting the possible geographic distribution of Bulinus truncatus snail (the intermediate host of Schistosoma haematobium), Odonata nymph (predatory aquatic insect), and Ceratophyllum demersum (the associated aquatic plant) in Egypt based on topographic and climatic factors. The models of the investigated species were evaluated using the area under receiver operating characteristic curve. The results showed that the potential risk areas were along the banks of the Nile River and its irrigation canals. In addition, the MaxEnt models revealed some similarities in the distribution pattern of the vector, the predator, and the aquatic plant. It is obvious that the predictive distribution range of B. truncatus was affected by altitude, precipitation seasonality, isothermality, and mean temperature of warmest quarter. The presence of B. truncatus decreases with the increase of altitude and precipitation seasonality values. It could be concluded that the MaxEnt model could help introducing a predictive risk map for Schistosoma haematobium prevalence and performing better management strategies for schistosomiasis.
Collapse
Affiliation(s)
- Marwa M Mahmoud
- Department of Entomology, Faculty of Science, Cairo University, Giza, Egypt. .,Department of Medical Malacology, Theodor Bilharz Research Institute, Giza, Egypt.
| | - Aly A Younes
- Department of Entomology, Faculty of Science, Cairo University, Giza, Egypt
| | - Hanaa A El-Sherif
- Department of Entomology, Faculty of Science, Cairo University, Giza, Egypt
| | - Fathia A Gawish
- Department of Medical Malacology, Theodor Bilharz Research Institute, Giza, Egypt
| | - Mohamed R Habib
- Department of Medical Malacology, Theodor Bilharz Research Institute, Giza, Egypt
| | - Mohamed Kamel
- Department of Environmental Basic Sciences, Institute of Environmental Studies and Research, Ain Shams University, Cairo, Egypt
| |
Collapse
|
4
|
Olkeba BK, Boets P, Mereta ST, Mandefro B, Debesa G, Ahmednur M, Ambelu A, Korma W, Goethals PLM. Malacological and Parasitological Surveys on Ethiopian Rift Valley Lakes: Implications for Control and Elimination of Snail-Borne Diseases. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 19:ijerph19010142. [PMID: 35010399 PMCID: PMC8750326 DOI: 10.3390/ijerph19010142] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 05/28/2023]
Abstract
Schistosomiasis is one of the snail-borne diseases responsible for the second-highest burden of diseases among neglected tropical diseases. The use of mass drug administration to the populations most at risk is a backbone of the strategy to prevent and control schistosomiasis transmission. However, it offers no protection against re-infection, and humans are often re-exposed when they return to water bodies where snails release cercariae. Surveys on cercarial infection in snails could provide better insights on human disease risk. Hence, in this study, we investigated cercarial infection in snails and also determined the epidemiology of Schistosoma mansoni among fishermen at Ethiopian Rift Valley lakes. Freshwater snails were collected from the shorelines of Ethiopian Rift Valley lakes for examination of cercarial infection during 2020. Environmental data on water quality variables and physical characteristics of snail habitats were collected. Stool samples were collected from fishermen and the Kato-Katz technique was applied for the quantification of Schistosoma mansoni eggs. A malacological survey indicated that six morphologically distinguishable types of cercariae were found in snails. Infected snails with cercaria were more likely present in habitats with high five-day biological oxygen demand and low dissolved oxygen. The overall prevalence of Schistosoma mansoni infection among the fishermen at Ethiopian Rift Valley lakes was found to be 21.5%. This indicates that fishermen at Ethiopian Rift Valley lakes are one of the groups of people harboring schistosome cercariae which are potentially responsible for the transmission of schistosomiasis to lakeshore communities who have contact with lake water. Therefore, complementary medical treatment, public health interventions, environmental management and snail reduction are needed to control the transmission of schistosomiasis.
Collapse
Affiliation(s)
- Beekam Kebede Olkeba
- Department of Animal Sciences and Aquatic Ecology, Ghent University, Coupure Links 653, Building F, 9000 Ghent, Belgium; (P.B.); (P.L.M.G.)
- Department of Environmental Health Science and Technology, Jimma University, Jimma 378, Ethiopia; (S.T.M.); (M.A.); (A.A.); (W.K.)
- Department of Environmental Health Science, Hawassa University, Hawassa 1560, Ethiopia
| | - Pieter Boets
- Department of Animal Sciences and Aquatic Ecology, Ghent University, Coupure Links 653, Building F, 9000 Ghent, Belgium; (P.B.); (P.L.M.G.)
- Provincial Centre of Environmental Research, Godshuizenlaan 95, 9000 Ghent, Belgium
| | - Seid Tiku Mereta
- Department of Environmental Health Science and Technology, Jimma University, Jimma 378, Ethiopia; (S.T.M.); (M.A.); (A.A.); (W.K.)
| | - Belayhun Mandefro
- Department of Biology, College of Natural and Computational Sciences, Dilla University, Dilla 419, Ethiopia;
| | - Gemechu Debesa
- Department of Geography and Environmental Studies, Jimma University, Jimma 378, Ethiopia;
| | - Mahmud Ahmednur
- Department of Environmental Health Science and Technology, Jimma University, Jimma 378, Ethiopia; (S.T.M.); (M.A.); (A.A.); (W.K.)
| | - Argaw Ambelu
- Department of Environmental Health Science and Technology, Jimma University, Jimma 378, Ethiopia; (S.T.M.); (M.A.); (A.A.); (W.K.)
| | - Wolyu Korma
- Department of Environmental Health Science and Technology, Jimma University, Jimma 378, Ethiopia; (S.T.M.); (M.A.); (A.A.); (W.K.)
| | - Peter L. M. Goethals
- Department of Animal Sciences and Aquatic Ecology, Ghent University, Coupure Links 653, Building F, 9000 Ghent, Belgium; (P.B.); (P.L.M.G.)
| |
Collapse
|
5
|
Manyangadze T, Chimbari MJ, Rubaba O, Soko W, Mukaratirwa S. Spatial and seasonal distribution of Bulinus globosus and Biomphalaria pfeifferi in Ingwavuma, uMkhanyakude district, KwaZulu-Natal, South Africa: Implications for schistosomiasis transmission at micro-geographical scale. Parasit Vectors 2021; 14:222. [PMID: 33892778 PMCID: PMC8063378 DOI: 10.1186/s13071-021-04720-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 04/06/2021] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Schsistosomiasis is endemic in sub-Saharan Africa. It is transmitted by intermediate host snails such as Bulinus and Biomphalaria. An understanding of the abundance and distribution of snail vectors is important in designing control strategies. This study describes the spatial and seasonal variation of B. globosus and Bio. pfeifferi and their schistosome infection rates between May 2014 and May 2015 in Ingwavuma, uMkhanyakude district, KwaZulu-Natal province, South Africa. METHODS Snail sampling was done on 16 sites once every month by two people for 30 min at each site using the scooping and handpicking methods. Snails collected from each site were screened for schistosome mammalian cercariae by the shedding method. The negative binomial generalised linear mixed model (glmm) was used to determine the relationship between abundances of the intermediate host snails and climatic factors [rainfall, land surface temperatures (LST), seasons, habitats, sampling sites and water physico-chemical parameters including pH and dissolved oxygen (DO)]. RESULTS In total, 1846 schistosomiasis intermediate host snails were collected during the study period. Biompharia pfeifferi was more abundant (53.36%, n = 985) compared to B. globosus (46.64%, n = 861). Bulinus globosus was recorded at 12 sites (75%) and Bio. pfeifferi was present at 7 sites (43.8%). Biompharia pfeifferi cohabited with B. globosus at all the sites it was present. High numbers of Bio. pfeifferi (n = 872, 88.5%) and B. globosus (n = 705, 81.9%) were found between winter and mid-spring. Monthly rainfall showed a statistically significant negative relationship with the abundance of B. globosus (p < 0.05). Dissolved oxygen (DO) had a statistically significant positive relationship with the abundance of Bio. pfeifferi (p < 0.05) while (LST) had a statistically significant negative relationship (p < 0.05). More B. globosus (8.9%, n = 861) were shedding schistosome mammalian cercariae compared to Bio. pfeifferi (0.1%, n = 985) confirming the already documented high prevalence of S. haematobium in Ingwavuma compared to S. mansoni. CONCLUSION Results of this study provide updated information on the distribution of schistosomiasis intermediate host snails in the study area and contributes towards the understanding of the transmission dynamics of schistosomiasis at the micro-geographical scale in this area.
Collapse
Affiliation(s)
- Tawanda Manyangadze
- School of Nursing and Public Health, Department of Public Health Medicine, University of KwaZulu-Natal, Durban, South Africa.
- Geography Department, Faculty of Science and Engineering, Bindura University of Science Education, Bag 1020, Bindura, Zimbabwe.
| | - Moses John Chimbari
- School of Nursing and Public Health, Department of Public Health Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - Owen Rubaba
- School of Nursing and Public Health, Department of Public Health Medicine, University of KwaZulu-Natal, Durban, South Africa
| | - White Soko
- School of Nursing and Public Health, Department of Public Health Medicine, University of KwaZulu-Natal, Durban, South Africa
- Ministry of Health and Child Care, De Beers Research Laboratory, P. O. Box 197, Chiredzi, Zimbabwe
| | - Samson Mukaratirwa
- School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
- Center for Zoonoses and Tropical Veterinary Medicine, Ross University School of Veterinary Medicine, Basseterre, St Kitts and Nevis
| |
Collapse
|
6
|
Habib MR, Lv S, Rollinson D, Zhou XN. Invasion and Dispersal of Biomphalaria Species: Increased Vigilance Needed to Prevent the Introduction and Spread of Schistosomiasis. Front Med (Lausanne) 2021; 8:614797. [PMID: 33644096 PMCID: PMC7902764 DOI: 10.3389/fmed.2021.614797] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 01/06/2021] [Indexed: 11/13/2022] Open
Abstract
Biological invasion is a matter of great concern from both public health and biodiversity perspectives. Some invasive snail species may trigger disease emergence by acting as intermediate hosts. The geographic distribution of Schistosoma mansoni depends on the presence of susceptible species of Biomphalaria freshwater snails that support the parasite's transformation into infective stages. Biomphalaria spp. have shown strong local and global dispersal capacities that may increase due to the global warming phenomenon and increases in the development of agricultural and water projects. Should intermediate hosts become established in new areas then this will create potential transmission foci. Examples of snail invasions that have had an impact on schistosomiasis transmission include the introduction of Biomphalaria tenagophila to Congo and B. glabrata to Egypt. The current spread of B. straminea in China is causing concern and needs to be monitored closely. An understanding of the mode of invasion and distribution of these snails as well as their experimental susceptibility to S. mansoni will predict the potential spread of schistosomiasis. Here we review the invasion patterns of Biomphalaria snails and factors that control their distribution and the impact that invasion may have on intestinal schistosomiasis transmission. In addition, we propose some possible surveillance responses for optimum control strategies and interventions. Whenever possible, swift action should be taken to contain any new occurrence of these intermediate snail hosts.
Collapse
Affiliation(s)
- Mohamed R. Habib
- Medical Malacology Laboratory, Theodor Bilharz Research Institute, Giza, Egypt
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention, Shanghai, China
- Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, China
| | - Shan Lv
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention, Shanghai, China
- Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, China
- National Center for International Research on Tropical Diseases, Shanghai, China
- WHO Collaborating Center on Tropical Diseases, Shanghai, China
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - David Rollinson
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Xiao-Nong Zhou
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention, Shanghai, China
- Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, China
- National Center for International Research on Tropical Diseases, Shanghai, China
- WHO Collaborating Center on Tropical Diseases, Shanghai, China
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| |
Collapse
|
7
|
Olkeba BK, Boets P, Mereta ST, Yeshigeta M, Akessa GM, Ambelu A, Goethals PLM. Environmental and biotic factors affecting freshwater snail intermediate hosts in the Ethiopian Rift Valley region. Parasit Vectors 2020; 13:292. [PMID: 32513295 PMCID: PMC7282061 DOI: 10.1186/s13071-020-04163-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 06/01/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Knowledge of the distribution and habitat preference of freshwater snail intermediate hosts can provide information to initiate and set-up effective snail control programmes. However, there is limited research conducted on the factors driving the occurrence and abundance of freshwater snail intermediate hosts in the Ethiopian Rift Valley. Hence, in this study, we investigated how environmental and biotic factors influence the occurrence and abundance of the snail intermediate hosts in Ethiopian Rift Valley region. METHODS Data on freshwater snails, physico-chemical water quality parameters, physical characteristics of habitat, predators and competitors, and anthropogenic activity variables were collected from 174 sampling sites during the wet season of 2017 and 2018. Generalized linear models were used to identify the main environmental and biotic factors affecting the occurrence and abundance of the snail species. RESULTS It was found that Bulinus globosus (31.7%) was the most abundant snail species followed by Lymnaea natalensis (21.6%), Lymnaea truncatula (15.1%) and Biomphalaria pfeifferi (14.6%). Generalized linear models indicated that physico-chemical parameters (water temperature, turbidity, chlorophyll-a, dissolved oxygen, chemical oxygen demand, alkalinity, calcium, magnesium, nitrate and ammonia), physical habitat characteristics (water depth, canopy cover, macrophyte cover and substrate type) and biotic factors (abundance of predators and competitors) were found to be the main variables determining the occurrence and abundance of snail species in the Ethiopian Rift Valley region. In terms of anthropogenic activities, human settlement, farming, bathing and swimming, clothes washing, grazing, drainage of land, car washing, boating, fishing and silviculture were also important variables determining the occurrence and abundance of snail species in the region. CONCLUSIONS The findings reported herein suggest that integrated snail control strategies should be considered to control snails via protection of water bodies from disturbance by anthropogenic activities. In this way, it is possible to reduce the concentration of organic matter and dissolved ions in aquatic ecosystems which are conducive for the presence of snails.
Collapse
Affiliation(s)
- Beekam Kebede Olkeba
- Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, Coupure Links 653, Building F, 9000, Ghent, Belgium. .,Department of Environmental Health Science and Technology, Jimma University, P.O.Box 378, Jimma, Ethiopia. .,Department of Environmental Health Science, Hawassa University, P.O.Box 1560, Hawassa, Ethiopia.
| | - Pieter Boets
- Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, Coupure Links 653, Building F, 9000, Ghent, Belgium.,Provincial Centre of Environmental Research, Godshuizenlaan 95, 9000, Ghent, Belgium
| | - Seid Tiku Mereta
- Department of Environmental Health Science and Technology, Jimma University, P.O.Box 378, Jimma, Ethiopia
| | - Mesfin Yeshigeta
- Department of Environmental Health Science and Technology, Jimma University, P.O.Box 378, Jimma, Ethiopia
| | - Geremew Muleta Akessa
- Departement of Statistics, College of Natural Science, Jimma University, P.O.Box 378, Jimma, Ethiopia
| | - Argaw Ambelu
- Department of Environmental Health Science and Technology, Jimma University, P.O.Box 378, Jimma, Ethiopia
| | - Peter L M Goethals
- Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, Coupure Links 653, Building F, 9000, Ghent, Belgium
| |
Collapse
|
8
|
Niu Y, Li R, Qiu J, Xu X, Huang D, Shao Q, Cui Y. Identifying and Predicting the Geographical Distribution Patterns of Oncomelania hupensis. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16122206. [PMID: 31234446 PMCID: PMC6616429 DOI: 10.3390/ijerph16122206] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 06/11/2019] [Accepted: 06/18/2019] [Indexed: 11/16/2022]
Abstract
Schistosomiasis is a snail-borne parasitic disease endemic to the tropics and subtropics, whose distribution depends on snail prevalence as determined by climatic and environmental factors. Here, dynamic spatial and temporal patterns of Oncomelania hupensis distributions were quantified using general statistics, global Moran’s I, and standard deviation ellipses, with Maxent modeling used to predict the distribution of habitat areas suitable for this snail in Gong’an County, a severely affected region of Jianghan Plain, China, based on annual average temperature, humidity of the climate, soil type, normalized difference vegetation index, land use, ditch density, land surface temperature, and digital elevation model variables; each variable’s contribution was tested using the jackknife method. Several key results emerged. First, coverage area of O. hupensis had changed little from 2007 to 2012, with some cities, counties, and districts alternately increasing and decreasing, with ditch and bottomland being the main habitat types. Second, although it showed a weak spatial autocorrelation, changing negligibly, there was a significant east–west gradient in the O. hupensis habitat area. Third, 21.9% of Gong’an County’s area was at high risk of snail presence; and ditch density, temperature, elevation, and wetting index contributed most to their occurrence. Our findings and methods provide valuable and timely insight for the control, monitoring, and management of schistosomiasis in China.
Collapse
Affiliation(s)
- Yingnan Niu
- Key Laboratory of Monitoring and Estimate for Environment and Disaster of Hubei Province, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China.
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Rendong Li
- Key Laboratory of Monitoring and Estimate for Environment and Disaster of Hubei Province, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China.
| | - Juan Qiu
- Key Laboratory of Monitoring and Estimate for Environment and Disaster of Hubei Province, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China.
| | - Xingjian Xu
- Hubei Provincial Center for Disease Control and Prevention, Wuhan 430079, China.
| | - Duan Huang
- Key Laboratory of Monitoring and Estimate for Environment and Disaster of Hubei Province, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China.
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Qihui Shao
- Key Laboratory of Monitoring and Estimate for Environment and Disaster of Hubei Province, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China.
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Ying Cui
- Key Laboratory of Monitoring and Estimate for Environment and Disaster of Hubei Province, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China.
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| |
Collapse
|
9
|
Schistosomiasis in Zambia: a systematic review of past and present experiences. Infect Dis Poverty 2018; 7:41. [PMID: 29706131 PMCID: PMC5925830 DOI: 10.1186/s40249-018-0424-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Accepted: 04/10/2018] [Indexed: 02/04/2023] Open
Abstract
Background The speedy rate of change in the environmental and socio-economics factors may increase the incidence, prevalence and risk of schistosomiasis infections in Zambia. However, available information does not provide a comprehensive understanding of the biogeography and distribution of the disease, ecology and population dynamics of intermediate host snails. The current study used an information-theoretical approach to understand the biogeography and prevalence schistosomiasis and identified knowledge gaps that would be useful to improve policy towards surveillance and eradication of intermediate hosts snails in Zambia. Methods To summarise the existing knowledge and build on past and present experiences of schistosomiasis epidemiology for effective disease control in Zambia, a systematic search of literature for the period 2000–2017 was done on PubMed, Google Scholar and EBSCOhost. Using the key words: ‘Schistosomiasis’, ‘Biomphalaria’, ‘Bulinus’, ‘Schistosoma mansoni’, ‘Schistosoma haematobium’, and ‘Zambia’, in combination with Booleans terms ‘AND’ and ‘OR’, published reports/papers were obtained and reviewed independently for inclusion. Results Thirteen papers published in English that fulfilled the inclusion criteria were selected for the final review. The papers suggest that the risk of infection has increased over the years and this has been attributed to environmental, socio-economic and demographic factors. Furthermore, schistosomiasis is endemic in many parts of the country with infection due to Schistosoma haematobium being more prevalent than that due to S. mansoni. This review also found that S. haematobium was linked to genital lesions, thus increasing risks of contracting other diseases such as HIV and cervical cancer. Conclusions For both S. haematobium and S. mansoni, environmental, socio-economic, and demographic factors were influential in the transmission and prevalence of the disease and highlight the need for detailed knowledge on ecological modelling and mapping the distribution of the disease and intermediate host snails for effective implementation of control strategies. Electronic supplementary material The online version of this article (10.1186/s40249-018-0424-5) contains supplementary material, which is available to authorized users.
Collapse
|
10
|
Alemayehu B, Tomass Z, Wadilo F, Leja D, Liang S, Erko B. Epidemiology of intestinal helminthiasis among school children with emphasis on Schistosoma mansoni infection in Wolaita zone, Southern Ethiopia. BMC Public Health 2017. [PMID: 28633651 PMCID: PMC5479011 DOI: 10.1186/s12889-017-4499-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Background Intestinal helminth infections are major parasitic diseases causing public health problems in Ethiopia. Although the epidemiology of these infections are well documented in Ethiopia, new transmission foci for schistosomiasis are being reported in different parts of the country. The objective of this study was to assess the prevalence of Schistosoma mansoni and other intestinal helminth infections among school children and determine the endemicity of schistosomiasis in Wolaita Zone, southern Ethiopia. Methods Cross-sectional parasitological and malacological surveys were conducted by collecting stool samples for microscopic examination and snails for intermediate host identification. Stool samples were collected from 503 children and processed for microscopic examination using Kato-Katz and formalin-ether concentration methods. Snails collected from aquatic environments in the study area were identified to species level and Biomphalaria pfeifferi snails, the intermediate host of S. mansoni,, were individually exposed to artificial light in order to induce cercariae shedding. Cercariae shed from snails were used to infect laboratory-bred Swiss albino mice in order to identify the schistosome to species level. Results The overall prevalence of intestinal helminth infections was 72.2% among school children. S. mansoni infection prevalence was 58.6%. The prevalence and intensity of S. mansoni infections varied among schools and sex of children. Swimming was the only factor reported to be significantly associated with S. mansoni infection (AOR = 2.954, 95% CI:1.962-4.449). Other intestinal helminth species identified were hookworms (27.6%), Ascaris lumbricoides (8.7%), E. vermicularis (2.8%), Taenia species (2.6%), T. trichiura (1.2%) and H. nana (0.6%). Only B. pfeifferi snails collected from streams shed schistosome cercariae and 792 adult S. mansoni worms were harvested from mice exposed to cercariae shed from B. pfeifferi on the 6th week post-exposure. Conclusion The present study found high level of intestinal helminth infections in the study area. The study also confirmed autochthonous transmission and endemicity of S. mansoni as evidenced by both parasitological and malacological findings as well as by further establishing infections in lab-bred mice. Therefore, there is a need to include the area in the control programs with anti-helminth drugs and also consider other complementary measures including sanitation, provision of clean water supply, and snail control.
Collapse
Affiliation(s)
- Bereket Alemayehu
- Biomedical Sciences Division, Department of Biology, College of Natural and Computational Sciences, Wolaita Sodo University, Wolaita Sodo, Ethiopia.
| | - Zewdneh Tomass
- Biomedical Sciences Division, Department of Biology, College of Natural and Computational Sciences, Wolaita Sodo University, Wolaita Sodo, Ethiopia
| | - Fiseha Wadilo
- Microbiology Unit, College of Health Sciences and Medicine, Wolaita Sodo University, Wolaita Sodo, Ethiopia
| | - Dawit Leja
- Biomedical Sciences Division, Department of Biology, College of Natural and Computational Sciences, Wolaita Sodo University, Wolaita Sodo, Ethiopia
| | - Song Liang
- Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, FL, 32610, USA
| | - Berhanu Erko
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| |
Collapse
|
11
|
Leite MGP, Pimenta EC, Fujaco MAG, Eskinazi-Sant'Anna EM. Irrigation canals in Melo creek basin (Rio Espera and Capela Nova municipalities, Minas Gerais, Brazil): habitats to Biomphalaria (Gastropoda: Planorbidae) and potential spread of schistosomiasis. BRAZ J BIOL 2017; 76:638-44. [PMID: 27097093 DOI: 10.1590/1519-6984.22714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 06/29/2015] [Indexed: 12/22/2022] Open
Abstract
This study analyzed the presence of Biomphalaria in Melo creek basin, Minas Gerais state, and its relationship to irrigation canals. Seventeen of these canals were used to determine a limnological, morphological and hydrological characterization during an annual seasonal cycle. Biomphalaria samples were sent to René Rachou Research Center/FIOCRUZ for identification and parasitological examination. Six canals were identified as breeding areas for mollusks and in one of them it was registered the coexistence of B. tenagophila (first report to this basin) and B. glabrata species. Results indicated that the low flow rate and speed of water flow were the main characteristics that contributed to this specific growth of the mollusks in the area. These hydraulic characteristics were created due to anthropogenic action through the canalization of lotic areas in Melo creek, which allowed ideal ecological conditions to Biomphalaria outbreak. The results emphasize the need of adequate handling and constant monitoring of the hydrographic basin, subject to inadequate phytosanitary conditions, aiming to prevent the occurrence and propagation of schistosomiasis.
Collapse
Affiliation(s)
- M G P Leite
- Departamento de Geologia, Universidade Federal de Ouro Preto, Universidade Federal de Ouro Preto, Ouro Preto MG , Brazil, Programa de Pós-graduação em Evolução Crustal e Recursos Naturais, Departamento de Geologia, Universidade Federal de Ouro Preto - UFOP, Campus Morro do Cruzeiro, CEP 35400-000, Ouro Preto, MG, Brazil
| | - E C Pimenta
- Departamento de Geologia, Universidade Federal de Ouro Preto, Universidade Federal de Ouro Preto, Ouro Preto MG , Brazil, Programa de Pós-graduação em Evolução Crustal e Recursos Naturais, Departamento de Geologia, Universidade Federal de Ouro Preto - UFOP, Campus Morro do Cruzeiro, CEP 35400-000, Ouro Preto, MG, Brazil
| | - M A G Fujaco
- Departamento de Geologia, Universidade Federal de Ouro Preto, Universidade Federal de Ouro Preto, Ouro Preto MG , Brazil, Programa de Pós-graduação em Evolução Crustal e Recursos Naturais, Departamento de Geologia, Universidade Federal de Ouro Preto - UFOP, Campus Morro do Cruzeiro, CEP 35400-000, Ouro Preto, MG, Brazil
| | - E M Eskinazi-Sant'Anna
- Departamento de Geologia, Universidade Federal de Ouro Preto, Universidade Federal de Ouro Preto, Ouro Preto MG , Brazil, Programa de Pós-graduação em Evolução Crustal e Recursos Naturais, Departamento de Geologia, Universidade Federal de Ouro Preto - UFOP, Campus Morro do Cruzeiro, CEP 35400-000, Ouro Preto, MG, Brazil.,Laboratório de Ecologia Aquática, Evolução e Conservação, Universidade Federal de Ouro Preto, Universidade Federal de Ouro Preto, Ouro Preto MG , Brazil, Laboratório de Ecologia Aquática, Evolução e Conservação, Universidade Federal de Ouro Preto - UFOP, Campus Morro do Cruzeiro, CEP 35400-000, Ouro Preto, MG, Brazil
| |
Collapse
|
12
|
Modelling the spatial and seasonal distribution of suitable habitats of schistosomiasis intermediate host snails using Maxent in Ndumo area, KwaZulu-Natal Province, South Africa. Parasit Vectors 2016; 9:572. [PMID: 27814746 PMCID: PMC5096326 DOI: 10.1186/s13071-016-1834-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 10/05/2016] [Indexed: 01/17/2023] Open
Abstract
Background Schistosomiasis is a snail-borne disease endemic in sub-Saharan Africa transmitted by freshwater snails. The distribution of schistosomiasis coincides with that of the intermediate hosts as determined by climatic and environmental factors. The aim of this paper was to model the spatial and seasonal distribution of suitable habitats for Bulinus globosus and Biomphalaria pfeifferi snail species (intermediate hosts for Schistosoma haematobium and Schistosoma mansoni, respectively) in the Ndumo area of uMkhanyakude district, South Africa. Methods Maximum Entropy (Maxent) modelling technique was used to predict the distribution of suitable habitats for B. globosus and B. pfeifferi using presence-only datasets with ≥ 5 and ≤ 12 sampling points in different seasons. Precipitation, maximum and minimum temperatures, Normalised Difference Vegetation Index (NDVI), Normalised Difference Water Index (NDWI), pH, slope and Enhanced Vegetation Index (EVI) were the background variables in the Maxent models. The models were validated using the area under the curve (AUC) and omission rate. Results The predicted suitable habitats for intermediate snail hosts varied with seasons. The AUC for models in all seasons ranged from 0.71 to 1 and the prediction rates were between 0.8 and 0.9. Although B. globosus was found at more localities in the Ndumo area, there was also evidence of cohabiting with B. pfiefferi at some of the locations. NDWI had significant contribution to the models in all seasons. Conclusion The Maxent model is robust in snail habitat suitability modelling even with small dataset of presence-only sampling sites. Application of the methods and design used in this study may be useful in developing a control and management programme for schistosomiasis in the Ndumo area.
Collapse
|
13
|
Oloyede OO, Otarigho B, Morenikeji O. Diversity, distribution and abundance of freshwater snails in Eleyele dam, Ibadan, south-west Nigeria. ACTA ACUST UNITED AC 2016. [DOI: 10.1080/21658005.2016.1245934] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Oyedibu Oyebayo Oloyede
- Ecology and Environmental Biology Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria
| | - Benson Otarigho
- Cellular Parasitology, Cell Biology and Genetic Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria
- Department of Biological Science, Edo University, Iyamho, Edo State, Nigeria
| | - Olajumoke Morenikeji
- Parasitology/Ecology and Environmental Biology Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria
| |
Collapse
|
14
|
Thiele EA, Corrêa-Oliveira G, Gazzinelli A, Minchella DJ. Elucidating the temporal and spatial dynamics of Biomphalaria glabrata genetic diversity in three Brazilian villages. Trop Med Int Health 2013; 18:1164-73. [PMID: 23911082 DOI: 10.1111/tmi.12164] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The freshwater snail Biomphalaria glabrata is the principal intermediate host for the parasite Schistosoma mansoni within Brazil. We assessed the potential effects of snail population dynamics on parasite transmission dynamics via population genetics. METHODS We sampled snail populations located within the confines of three schistosome-endemic villages in the state of Minas Gerais, Brazil. Snails were collected from individual microhabitats following seasonal periods of flood and drought over the span of 1 year. Snail spatio-temporal genetic diversity and population differentiation of 598 snails from 12 sites were assessed at seven microsatellite loci. RESULTS Average genetic diversity was relatively low, ranging from 4.29 to 9.43 alleles per locus, and overall, subpopulations tended to exhibit heterozygote deficits. Genetic diversity was highly spatially partitioned among subpopulations, while virtually, no partitioning was observed across temporal sampling. Comparison with previously published parasite genetic diversity data indicated that S. mansoni populations are significantly more variable and less subdivided than those of the B. glabrata intermediate hosts. DISCUSSION Within individual Brazilian villages, observed distributions of snail genetic diversity indicate temporal stability and very restricted gene flow. This is contrary to observations of schistosome genetic diversity over the same spatial scale, corroborating the expectation that parasite gene flow at the level of individual villages is likely driven by vertebrate host movement.
Collapse
Affiliation(s)
- Elizabeth A Thiele
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | | | | | | |
Collapse
|
15
|
Abd El-Wakeil KF, Obuid-Allah AH, Mohamed AH, Abd El-Aziz FEZA. Community structure of molluscans in River Nile and its branches in Assiut governorate, Egypt. THE EGYPTIAN JOURNAL OF AQUATIC RESEARCH 2013; 39:193-198. [DOI: 10.1016/j.ejar.2013.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
|
16
|
Kloos H, Quites HFO, Oliveira RC, Loverde P, Gazzinelli A. Rural electrification in Brazil and implications for schistosomiasis transmission: a preliminary study in a rural community in Minas Gerais State, Brazil. Trop Med Int Health 2012; 17:526-30. [PMID: 22413834 DOI: 10.1111/j.1365-3156.2012.02962.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES To evaluate the potential transmission of Schistosoma mansoni through well water pumped into households in a rural Brazilian community within the context of Brazil's rural electrification program Luz Para Todos (Light for All). METHODS All households were interviewed about their water facilities and domestic water use, all household members were examined for S. mansoni infections and positives treated, and malacological and water contact studies were performed between 2001 and 2009. RESULTS Thirty-one of the 142 households in the Virgem das Graças study area owned wells with electric pumps in 2009, vs. no wells in 2001, and the number of water storage tanks increased from 85 to 131. The potential for schistosomiasis transmission through piped well water was indicated by the recovery of Biomphalaria gabrata, including S. mansoni-infected snails, from wells, the presence of Biomphalaria in tanks and the ability of S. mansoni cercariae to remain infective for considerable distances in flowing water. However, access to well water was not associated with higher S. mansoni infection rates. CONCLUSIONS Our results indicate that further studies are needed to determine the infectivity of well water and its impact on schistosomiasis transmission.
Collapse
Affiliation(s)
- Helmut Kloos
- Department of Epidemiology and Biostatistics, University of California Medical Center, San Francisco, CA, USA
| | | | | | | | | |
Collapse
|
17
|
Kloos H, Correa-Oliveira R, dos Reis DC, Rodrigues EW, Monteiro LAS, Gazzinelli A. The role of population movement in the epidemiology and control of schistosomiasis in Brazil: a preliminary typology of population movement. Mem Inst Oswaldo Cruz 2011; 105:578-86. [PMID: 20721511 DOI: 10.1590/s0074-02762010000400038] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Accepted: 12/18/2009] [Indexed: 11/21/2022] Open
Abstract
This paper examines recent developments in migration studies. It reviews literature related to the potential role of internal population movement in the occurrence of schistosomiasis in Brazil and modifies Prothero's typology of population movement for use in Brazil. This modified classification system may contribute to a better understanding of schistosome transmission as well as improved research and control programs. The results of this study indicate that population movement in Brazil primarily involves economically-motivated rural-urban and interregional movement. However, several movement patterns have become increasingly important in recent years as a result of changing socioeconomic and urbanisation dynamics. These patterns include urban-urban, intracity and urban-rural movement as well as the movement of environmental refugees and tourists. Little is known about the epidemiological significance of these patterns. This paper also highlights the role of social networks in the decision to migrate and to settle. Prothero's classic population movement typology categorises movement as either one-way migrations or circulations and examines them along spatial and temporal scales. However, the typology must be modified as epidemiological information about new patterns becomes available. This paper identifies areas that require further research and offers recommendations that can improve the measurement and spatial analysis of the relationship between population movement and schistosomiasis.
Collapse
Affiliation(s)
- Helmut Kloos
- Department of Epidemiology and Biostatistics, University of California Medical Center, San Francisco, California, USA
| | | | | | | | | | | |
Collapse
|
18
|
Steinauer ML, Blouin MS, Criscione CD. Applying evolutionary genetics to schistosome epidemiology. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2010; 10:433-43. [PMID: 20176142 PMCID: PMC2861999 DOI: 10.1016/j.meegid.2010.02.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 02/09/2010] [Accepted: 02/15/2010] [Indexed: 10/19/2022]
Abstract
We review how molecular markers and evolutionary analysis have been applied to the study of schistosome parasites, important pathogens that infect over 200 million people worldwide. Topics reviewed include phylogenetics and biogeography, hybridization, infection within snails, mating systems, and genetic structure. Some interesting generalizations include that schistosome species hybridize frequently and have switched definitive hosts repeatedly in evolutionary time. We show that molecular markers can be used to infer epidemiologically relevant processes such as spatial variation in transmission, or to reveal complex patterns of mate choice. Analysis of genetic structure data shows that transmission foci can be structured by watershed boundaries, habitat types, and host species. We also discuss sampling and analytical problems that arise when using larvae to estimate genetic parameters of adult schistosome populations. Finally, we review pitfalls in methodologies such as genotyping very small individuals, statistical methods for identifying clonemates or for identifying sibling groups, and estimating allele frequencies from pooled egg samples.
Collapse
Affiliation(s)
- Michelle L Steinauer
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 105 Magruder Hall, Corvallis, OR 97331, United States.
| | | | | |
Collapse
|
19
|
Thiele EA, Sorensen RE, Gazzinelli A, Minchella DJ. Genetic diversity and population structuring of Schistosoma mansoni in a Brazilian village. Int J Parasitol 2007; 38:389-99. [PMID: 17825305 PMCID: PMC2476926 DOI: 10.1016/j.ijpara.2007.07.011] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Revised: 07/07/2007] [Accepted: 07/10/2007] [Indexed: 11/20/2022]
Abstract
The digenean trematode Schistosoma mansoni is responsible for chronic schistosomiasis worldwide, and in Brazil alone an estimated 35 million people are at risk. To evaluate epidemiological patterns among human definitive hosts, we assessed genetic diversity and population subdivision of S. mansoni infrapopulations in human hosts from the highly endemic village of Virgem das Graças in the state of Minas Gerais, Brazil. We believe this is the largest such survey to date. Genetic diversity of parasites, measured over eight polymorphic microsatellite loci, was relatively high and standard measures of inbreeding indicated that the population was panmictic. Furthermore, there was no significant isolation-by-distance of parasite infrapopulations, and measures of population subdivision indicated significant but low to moderate levels of population differentiation. We conclude that patients within this village sample from a broad range of schistosome genetic diversity and effectively act as "genetic mixing bowls" for the parasites. These results contrast with those previously observed in the Brazilian village of Melqui ades and thus provide the opportunity for comparisons of environmental and epidemiological differences that are likely to influence host-parasite coevolution and parasite transmission.
Collapse
Affiliation(s)
- E A Thiele
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA.
| | | | | | | |
Collapse
|
20
|
Ruelas DS, Karentz D, Sullivan JT. Lethal and sub-lethal effects of UVB on juvenile Biomphalaria glabrata (Mollusca: Pulmonata). J Invertebr Pathol 2006; 93:192-200. [PMID: 16996081 PMCID: PMC1824712 DOI: 10.1016/j.jip.2006.08.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Revised: 07/20/2006] [Accepted: 08/02/2006] [Indexed: 11/16/2022]
Abstract
Although Schistosoma mansoni occurs mainly in the tropics, where intense levels of solar radiation are present, the impact of ultraviolet (UV) light on schistosome transmission is not known. The purpose of this study was to investigate potential effects of UVB (290-320nm) on juvenile Biomphalaria glabrata, the snail intermediate host of S. mansoni. Albino and wild-type snails were exposed to doses of UVB from UV-fluorescent lamps, and the following were measured: survival, photoreactivation (light-mediated DNA repair), effects on feeding behavior, and morphological tissue abnormalities. Irradiation with UVB is lethal to B. glabrata in a dose-dependent manner. Exposure to white light subsequent to UVB irradiation enhances survival, probably by photoreactivation. The shell offers some, but not complete, protection. Experiments in which UVB transmittance through the shell was blocked with black nail polish suggest that injury to both exposed (headfoot) and shell-enclosed (mantle and visceral mass) tissues contributes to mortality in lethally irradiated snails. Wild-type (pigmented) snails are less susceptible to lethal effects of UVB than albino snails, and they may be more capable of photoreactivation. UVB exposure inhibits snail feeding behavior, and causes tentacle forks and growths on the headfoot. Thus, UVB may influence the life cycle of S. mansoni by both lethal and sub-lethal damage to the snail intermediate host. However, the ability of snails to photoreactivate may mitigate these effects.
Collapse
Affiliation(s)
- Debbie S Ruelas
- Department of Biology, University of San Francisco, 2130 Fulton Street, San Francisco, CA 94117, USA
| | | | | |
Collapse
|
21
|
Minchella DJ. PRESIDENTIAL ADDRESS: THE ROLE OF VARIATION IN HOST-PARASITE INTERACTIONS: LINKING GENETIC DEMES AND LIFE HISTORY SCHEMES. J Parasitol 2005; 91:1246-52. [PMID: 16539000 DOI: 10.1645/ge-703.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Dennis J Minchella
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-2054, USA.
| |
Collapse
|
22
|
Giovanelli A, da Silva CLPAC, Leal GBE, Baptista DF. Habitat preference of freshwater snails in relation to environmental factors and the presence of the competitor snail Melanoides tuberculatus (Müller, 1774). Mem Inst Oswaldo Cruz 2005; 100:169-76. [PMID: 16021304 DOI: 10.1590/s0074-02762005000200010] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Our objective is to evaluate the habitat preference of freshwater snails in relation to environmental factors and the presence of the competitor snail Melanoides tuberculatus. In the first phase, snails was collected at 12 sites. This sampling sites presented a degree of organic input. In the second phase 33 sampling sites were chosen, covering a variety of lotic and lentic environments. The snail species found at Guapimirim, state of Rio de Janeiro, displayed a marked habitat preference, specially in relation to the physical characteristics of each environment. Other limiting factors for snail distribution at the studied lotic environments were the water current velocity and the amount of organic matter, mainly to Physa marmorata, M. tuberculatus, and Biomphalaria tenagophila. The absence of interactions between M. tuberculatus and another snails could be associated to the distinct spatial distribution of those species and the instability of habitats. This later factor may favor the coexistence of M. tuberculatus with B. glabrata by reduction of population density. In areas of schistosomiasis transmission some habitat modification may add to the instability of the environment, which would make room for the coexistence of M. tuberculatus and Biomphalaria spp. In this way, some of the usual measures for the control of snail hosts would prevent the extinction of populations of Biomphalaria spp. by M. tuberculatus in particular habitats.
Collapse
Affiliation(s)
- Alexandre Giovanelli
- Laboratório da Avaliação e Promoção da Saúde Ambiental, Departamento de Biologia, Instituto Oswaldo Cruz-Fiocruz, Av. Brasil 4365, 21045-900 Rio de Janeiro, RJ, Brasil
| | | | | | | |
Collapse
|
23
|
Abstract
No Brasil, índices elevados da esquistossomose mansônica correspondem, na grande maioria dos casos, à presença da espécie Biomphalaria glabrata, principal transmissora do Schistosoma mansoni, nas localidades endêmicas. Foi realizado estudo em 40 municípios endêmicos do Estado de Alagoas, com o objetivo de verificar a existência da espécie e sua importância na manutenção da esquistossomose nesse Estado. Desses municípios, 28 são pertencentes à mesorregião do leste Alagoano e 12 à mesorregião do Agreste Alagoano. Os moluscos procederam de diversos tipos de criadouros: riachos, córregos, valas, açudes, brejos e poços. As coletas foram realizadas no período de fevereiro de 1996 a dezembro de 1998. Para a identificação de Biomphalaria glabrata, foi efetuado o exame anatômico das partes moles, após remoção das conchas. A detecção de cercárias do Schistosoma mansoni foi realizada através da técnica de esmagamento, calculando-se o percentual de infecção. Em 32 (80%) dos municípios estudados foi encontrada Biomphalaria glabrata, seis deles apresentando moluscos infectados com cercárias do parasita. Penedo apresentou a maior (6,6%) taxa de infecção, seguindo-se Ibateguara (5,6%). Taxas menores foram observadas em Chã Preta (2,7%), em Murici (2,5%), Porto Real do Colégio (0,1%) e Igreja Nova (0,1%). O inquérito copro-parasitológico efetuado pela Fundação Nacional de Saúde em 1997, 1998/1999 e 2000, confirmou a importância da endemia nessas regiões do Estado.
Collapse
Affiliation(s)
- Janira Lúcia Assumpção Couto
- Departamento de Patologia, Centro de Ciências Biológicas, Universidade Federal de Alagoas, R. Desp. Humberto Guimarães 191/102, Ponta Verde, 57035-030 Maceió, Alagoas, Brazil.
| |
Collapse
|
24
|
Kloos H, Passos LKJ, Loverde P, Oliveira RC, Gazzinelli A. Distribution and Schistosoma mansoni infection of Biomphalaria glabrata in different habitats in a rural area in the Jequitinhonha Valley, Minas Gerais, Brazil: environmental and epidemiological aspects. Mem Inst Oswaldo Cruz 2004; 99:673-81. [PMID: 15654420 DOI: 10.1590/s0074-02762004000700002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This paper examines the distribution and infection of Biomphalaria glabrata with Schistosoma mansoni in all aquatic snail habitats in a rural area in the state of Minas Gerais, Brazil, in relation to physico/biotic and behavioral factors. Snail and environmental surveys were carried out semi-annually between July 2001 and November 2002 at 106 sites. Collected snails were examined in the laboratory for infection. B. glabrata densities were highest in overflow ponds, irrigation ponds, springs, canals and wells, and lowest in fishponds and water tanks. Snail densities were higher during the hot, rainy season except for streams and canals and were statistically associated with the presence of fish, pollution, and vegetation density. Tilapia fish and an unidentified Diptera larva were found to be predators of B. glabrata but ducks were not. Twenty-four of the 25 infected snails were collected in 2001(1.4% infection rate) and only one in 2002, after mass chemotherapy. The occurrence of B. glabrata in all 11 snail habitats both at and away from water contact sites studied indicates widespread risk of human infection in the study area. In spite of the strong association between B. glabrata and tilapia in fishponds we do not recommend its use in schistosomiasis control for ecological reasons and its relative inefficiency in streams and dams.
Collapse
Affiliation(s)
- Helmut Kloos
- Department of Epidemiology and Biostatistics, University of California, San Francisco, USA
| | | | | | | | | |
Collapse
|