Malaria incidence in urban areas has generally been low compared to rural areas but recent data indicate that urban malaria remains a public health problem. It is therefore important to understand the factors that pro...Malaria incidence in urban areas has generally been low compared to rural areas but recent data indicate that urban malaria remains a public health problem. It is therefore important to understand the factors that promote urban malaria to help formulate future vector control strategies. This study compared Anopheles gambiae s.l. (A. gambiae s.l.) species composition, distribution and insecticide resistance mechanisms between vegetable and non-vegetable growing areas in Accra Metropolis. Four sites were selected within the city of Accra which comprised of two vegetable-growing and two non-vegetable growing areas. WHO susceptibility tests were carried out on adults A. gambiae s.l. reared from larvae collected from the sites. Five insecticides were tested and the A. gambiae complex, resistance genotypes and enzyme activities of each population were characterized. All A. gambiae s.l. populations tested were resistant to all the insecticides, but relatively lower mortalities were observed in the vegetable growing areas. The mortality against 0.05% deltamethrin was 2.6% (Opeibea) and 12.5% (Korle-Bu) for the vegetable growing areas and 36.2% (Achimota) and 38.9% (Mataheko) in the non-vegetable growing areas. Anopheles gambiae s.s. (95% of Opeibea population) and Anopheles coluzzii, (98% of Korle-Bu population) were the dominant species in the vegetable growing areas. The voltage-gated sodium channel (Vgsc-1014F) frequencies of all the populations were similar but the acetylcholinesterase (ace-1) frequencies were significantly lower (p A. gambiae s.l. from Opeibea than from the other areas. The contribution of urban agriculture in the development of insecticide resistance needs to be considered in the formulation of future vector control strategies alongside other domestic usages.展开更多
Kogyae Strict Nature Reserve, the only one in Ghana, was established to promote scientific research, particularly on how nature revitalizes itself after major disasters, and also to check the southward drift of the sa...Kogyae Strict Nature Reserve, the only one in Ghana, was established to promote scientific research, particularly on how nature revitalizes itself after major disasters, and also to check the southward drift of the savannah grassland. This study presents the first comprehensive inventory of species composition and diversity of insects of the Reserve. Insects were surveyed between September 2011 and June 2012 to capture the end of the rainy season, the dry season and the peak of the wet season. Samples were taken from two sites within the Reserve, Dagomba and Oku using various sampling techniques including pitfall traps, malaise traps and sweep nets. Insect communities were characterized in terms of, 1) species richness estimators, 2) species richness, 3) Shannon-Weiner Index of Diversity, 4) Pielou’s evenness and 5) Bray-Curtis similarity. A total of 8147 individuals representing 135 families from 21 orders were recorded. This included 107 species of butterflies from 9 families and 20 species of dragonflies from 3 families. Oku recorded the highest species numbers (S = 63) and richness (d = 12.16) with a high evenness of species (J = 0.9377) during the peak of the wet season;and the lowest species numbers (S = 58) and Margalef’s index of (d = 10.14) in January. The highest Shannon diversity index of (H = 3.927) was recorded at Dagomba in January.展开更多
In a bid to enhance the integrity and health of selected network of ecosystems and effectively manage them in Sierra Leone, a baseline assessment of butterfly diversity of two wetland ecosystems Mamunta Mayosso Wildli...In a bid to enhance the integrity and health of selected network of ecosystems and effectively manage them in Sierra Leone, a baseline assessment of butterfly diversity of two wetland ecosystems Mamunta Mayosso Wildlife Santuary (MMWS) and Sierra Leone River Estuary (SLRE) affected by different environmental stressors was undertaken as part of the Sierra Leone Wetland Conservation Project (SLWCP). We hypothesised that different environmental stressors affect butterfly communities in wetlands in Sierra Leone and the higher the stress the lower the butterfly diversity in an area. Sampling was conducted via field identification by wing patterns, flight mode, direct counts along transects and charaxes trapping. A total of 2300 individuals representing 95 species of butterflies were recorded. Though butterflies were evenly distributed at both sites, MMWS recorded the highest richness and abundance of butterflies during both seasons. This observation is reported to be because of high environmental stressors such as mining, agriculture and pollution from factories in the SLRE. The results further show that MMWS is made up of a mosaic of different vegetation patches that support higher diversity of butterfly species. This study also reveals that anthropogenic activities have a negative impact on butterfly diversity.展开更多
Aedes-borne diseases remain a public health challenge for many countries globally. The extent of spread of invasive species of Aedes mosquitoes and risk of transmission of the diseases especially around the point of e...Aedes-borne diseases remain a public health challenge for many countries globally. The extent of spread of invasive species of Aedes mosquitoes and risk of transmission of the diseases especially around the point of entry of goods such as ports is not well known in Ghana. This study investigated the ecology, distribution and risk of transmission of viral haemorrhagic fevers by Aedes mosquitoes around the port areas of Tema, Southern Ghana. The mosquitoes from this study were collected using human landing catches, ovitraps and larval collections for a period of six months. A total of 1092 containers were inspected in both seasons and of these, 237 (21.7%) were positive for mosquito larvae or pupae in rainy season while 181 (16.6%) were positive in dry season. A total of 6498 mosquitoes were collected and identified morphologically using taxonomic keys. 6038 (92.9%) were Aedes aegypti, 337 (5.2%) were Culex spp. and 123 (1.9%) were Anopheles gambiae. The Ae. aegypti larvae were found breeding in a series of water-holding containers which included disposed plastic containers, earthenware pots, car tyres, plastic barrels, plastic basins, buckets, metal drums, jerrycans and poly tank. A high proportion of Aedes aegypti eggs were found in the ovitraps during the rainy season than in the dry season in the study sites. Ae. aegypti was the most common mosquitoes biting mostly outdoors (65.6%) with more bites occurring in the rainy season (63.6%) in the two residential sites (Tema Community One and Tema New Town). The risk of transmission of viral haemorrhagic fever in the study sites was assessed using House Index, Container Index, Breteau Index and was found to be higher in Tema New town area with seasonal variations within the sites. The man-vector contact rates for the two residential sites were also found to be higher in rainy season than the dry season. These observations indicate that the risk of transmission of viral haemorrhagic fevers in the study areas is high especially in the rainy season. The implications of the findings in the formulation of future vector control programmes around the port areas in the country are discussed in the paper.展开更多
Background:Mass drug administration(MDA)programmes for the control of lymphatic filariasis in Ghana,have been ongoing in some endemic districts for 16 years.The current study aimed to assess factors that govern the su...Background:Mass drug administration(MDA)programmes for the control of lymphatic filariasis in Ghana,have been ongoing in some endemic districts for 16 years.The current study aimed to assess factors that govern the success of MDA programmes for breaking transmission of lymphatic filariasis in Ghana.Methods:The study was undertaken in two"hotspot"districts(Ahanta West and Kassena Nankana West)and two control districts(Mpohor and Bongo)in Ghana.Mosquitoes were collected and identified using morphological and molecular tools.A proportion of the cibarial armatures of each species was examined.Dissections were performed onAnopheles gambiae for filarial worm detection.A questionnaire was administered to obtain information on MDA compliance and vector control activities.Data were compared between districts to determine factors that might explain persistent transmission of lymphatic filariasis.Results:High numbers of mosquitoes were sampled in Ahanta West district compared to Mpohor district(F=16.09,P=0.002).There was no significant difference between the numbers of mosquitoes collected in Kassena Nankana West and Bongo districts(F=2.16,P=0.185).Mansonia species were predominant in Ahanta West district.An.coluzzii mosquitoes were prevalent in all districts.An.melas with infected and infective filarial worms was found only in Ahanta West district.No differences were found in cibarial teeth numbers and shape for mosquito species in the surveyed districts.Reported MDA coverage was high in all districts.The average use of bednet and indoor residual spraying was 82.4 and 66.2%,respectively.There was high compliance in the five preceding MDA rounds in Ahanta West and Kassena Nankana West districts,both considered hotspots of lymphatic filariasis transmission.Conclusions:The study on persistent transmission of lymphatic filariasis in the two areas in Ghana present information that shows the importance of local understanding of factors affecting control and elimination of lymphatic filariasis.Unlike Kassena Nankana West district where transmission dynamics could be explained by initial infection prevalence and low vector densities,ongoing lymphatic filariasis transmission in Ahanta West district might be explained by high biting rates ofAn.gambiae and initial infection prevalence,coupled with high densities ofAn.melas andMansonia vector species that have low or no teeth and exhibiting limitation.展开更多
文摘Malaria incidence in urban areas has generally been low compared to rural areas but recent data indicate that urban malaria remains a public health problem. It is therefore important to understand the factors that promote urban malaria to help formulate future vector control strategies. This study compared Anopheles gambiae s.l. (A. gambiae s.l.) species composition, distribution and insecticide resistance mechanisms between vegetable and non-vegetable growing areas in Accra Metropolis. Four sites were selected within the city of Accra which comprised of two vegetable-growing and two non-vegetable growing areas. WHO susceptibility tests were carried out on adults A. gambiae s.l. reared from larvae collected from the sites. Five insecticides were tested and the A. gambiae complex, resistance genotypes and enzyme activities of each population were characterized. All A. gambiae s.l. populations tested were resistant to all the insecticides, but relatively lower mortalities were observed in the vegetable growing areas. The mortality against 0.05% deltamethrin was 2.6% (Opeibea) and 12.5% (Korle-Bu) for the vegetable growing areas and 36.2% (Achimota) and 38.9% (Mataheko) in the non-vegetable growing areas. Anopheles gambiae s.s. (95% of Opeibea population) and Anopheles coluzzii, (98% of Korle-Bu population) were the dominant species in the vegetable growing areas. The voltage-gated sodium channel (Vgsc-1014F) frequencies of all the populations were similar but the acetylcholinesterase (ace-1) frequencies were significantly lower (p A. gambiae s.l. from Opeibea than from the other areas. The contribution of urban agriculture in the development of insecticide resistance needs to be considered in the formulation of future vector control strategies alongside other domestic usages.
文摘Kogyae Strict Nature Reserve, the only one in Ghana, was established to promote scientific research, particularly on how nature revitalizes itself after major disasters, and also to check the southward drift of the savannah grassland. This study presents the first comprehensive inventory of species composition and diversity of insects of the Reserve. Insects were surveyed between September 2011 and June 2012 to capture the end of the rainy season, the dry season and the peak of the wet season. Samples were taken from two sites within the Reserve, Dagomba and Oku using various sampling techniques including pitfall traps, malaise traps and sweep nets. Insect communities were characterized in terms of, 1) species richness estimators, 2) species richness, 3) Shannon-Weiner Index of Diversity, 4) Pielou’s evenness and 5) Bray-Curtis similarity. A total of 8147 individuals representing 135 families from 21 orders were recorded. This included 107 species of butterflies from 9 families and 20 species of dragonflies from 3 families. Oku recorded the highest species numbers (S = 63) and richness (d = 12.16) with a high evenness of species (J = 0.9377) during the peak of the wet season;and the lowest species numbers (S = 58) and Margalef’s index of (d = 10.14) in January. The highest Shannon diversity index of (H = 3.927) was recorded at Dagomba in January.
文摘In a bid to enhance the integrity and health of selected network of ecosystems and effectively manage them in Sierra Leone, a baseline assessment of butterfly diversity of two wetland ecosystems Mamunta Mayosso Wildlife Santuary (MMWS) and Sierra Leone River Estuary (SLRE) affected by different environmental stressors was undertaken as part of the Sierra Leone Wetland Conservation Project (SLWCP). We hypothesised that different environmental stressors affect butterfly communities in wetlands in Sierra Leone and the higher the stress the lower the butterfly diversity in an area. Sampling was conducted via field identification by wing patterns, flight mode, direct counts along transects and charaxes trapping. A total of 2300 individuals representing 95 species of butterflies were recorded. Though butterflies were evenly distributed at both sites, MMWS recorded the highest richness and abundance of butterflies during both seasons. This observation is reported to be because of high environmental stressors such as mining, agriculture and pollution from factories in the SLRE. The results further show that MMWS is made up of a mosaic of different vegetation patches that support higher diversity of butterfly species. This study also reveals that anthropogenic activities have a negative impact on butterfly diversity.
文摘Aedes-borne diseases remain a public health challenge for many countries globally. The extent of spread of invasive species of Aedes mosquitoes and risk of transmission of the diseases especially around the point of entry of goods such as ports is not well known in Ghana. This study investigated the ecology, distribution and risk of transmission of viral haemorrhagic fevers by Aedes mosquitoes around the port areas of Tema, Southern Ghana. The mosquitoes from this study were collected using human landing catches, ovitraps and larval collections for a period of six months. A total of 1092 containers were inspected in both seasons and of these, 237 (21.7%) were positive for mosquito larvae or pupae in rainy season while 181 (16.6%) were positive in dry season. A total of 6498 mosquitoes were collected and identified morphologically using taxonomic keys. 6038 (92.9%) were Aedes aegypti, 337 (5.2%) were Culex spp. and 123 (1.9%) were Anopheles gambiae. The Ae. aegypti larvae were found breeding in a series of water-holding containers which included disposed plastic containers, earthenware pots, car tyres, plastic barrels, plastic basins, buckets, metal drums, jerrycans and poly tank. A high proportion of Aedes aegypti eggs were found in the ovitraps during the rainy season than in the dry season in the study sites. Ae. aegypti was the most common mosquitoes biting mostly outdoors (65.6%) with more bites occurring in the rainy season (63.6%) in the two residential sites (Tema Community One and Tema New Town). The risk of transmission of viral haemorrhagic fever in the study sites was assessed using House Index, Container Index, Breteau Index and was found to be higher in Tema New town area with seasonal variations within the sites. The man-vector contact rates for the two residential sites were also found to be higher in rainy season than the dry season. These observations indicate that the risk of transmission of viral haemorrhagic fevers in the study areas is high especially in the rainy season. The implications of the findings in the formulation of future vector control programmes around the port areas in the country are discussed in the paper.
基金This study was supported by SightSavers International,Ghana and the Centre for Neglected Tropical Diseases,Liverpool School of Tropical MedicineSPB is grateful to the "Amt fur Ausbildungsbeitrage"of the canton of Basel-Stadt for a PhD fellowship.
文摘Background:Mass drug administration(MDA)programmes for the control of lymphatic filariasis in Ghana,have been ongoing in some endemic districts for 16 years.The current study aimed to assess factors that govern the success of MDA programmes for breaking transmission of lymphatic filariasis in Ghana.Methods:The study was undertaken in two"hotspot"districts(Ahanta West and Kassena Nankana West)and two control districts(Mpohor and Bongo)in Ghana.Mosquitoes were collected and identified using morphological and molecular tools.A proportion of the cibarial armatures of each species was examined.Dissections were performed onAnopheles gambiae for filarial worm detection.A questionnaire was administered to obtain information on MDA compliance and vector control activities.Data were compared between districts to determine factors that might explain persistent transmission of lymphatic filariasis.Results:High numbers of mosquitoes were sampled in Ahanta West district compared to Mpohor district(F=16.09,P=0.002).There was no significant difference between the numbers of mosquitoes collected in Kassena Nankana West and Bongo districts(F=2.16,P=0.185).Mansonia species were predominant in Ahanta West district.An.coluzzii mosquitoes were prevalent in all districts.An.melas with infected and infective filarial worms was found only in Ahanta West district.No differences were found in cibarial teeth numbers and shape for mosquito species in the surveyed districts.Reported MDA coverage was high in all districts.The average use of bednet and indoor residual spraying was 82.4 and 66.2%,respectively.There was high compliance in the five preceding MDA rounds in Ahanta West and Kassena Nankana West districts,both considered hotspots of lymphatic filariasis transmission.Conclusions:The study on persistent transmission of lymphatic filariasis in the two areas in Ghana present information that shows the importance of local understanding of factors affecting control and elimination of lymphatic filariasis.Unlike Kassena Nankana West district where transmission dynamics could be explained by initial infection prevalence and low vector densities,ongoing lymphatic filariasis transmission in Ahanta West district might be explained by high biting rates ofAn.gambiae and initial infection prevalence,coupled with high densities ofAn.melas andMansonia vector species that have low or no teeth and exhibiting limitation.
