Objective:To study the distribution and abundance of Biomphalaria(B.)pfeifferi species in the Mwea Irrigation Scheme,their role as intermediate hosts for Schistosoma(S.)mansoni,and the impact of water parameters.Metho...Objective:To study the distribution and abundance of Biomphalaria(B.)pfeifferi species in the Mwea Irrigation Scheme,their role as intermediate hosts for Schistosoma(S.)mansoni,and the impact of water parameters.Methods:A longitudinal field survey was conducted across eight administrative wards and five habitat types using a time-based metal scoop method.Physicochemical water quality parameters were measured both in situ and in the laboratory.The snails were examined for S.mansoni infections by shedding method,and cercariae were identified microscopically.Species identification was also performed.The data was analyzed using ANOVA,regression analysis,and Pearson correlation to identify the association between water physiochemical parameters and Biomphalaria snail abundance.Level of significance was determined at 5%(P≤0.05)with 95%confidence limit.Results:A total of 2013 Biomphalaria species were collected,mainly from Murinduko and Nyangati Wards.Streams(965,47.93%)and tertiary canals(676,33.58%)showed the highest abundance.Biomphalaria species populations were recorded in September 2022(1225),with declines noted in February and August 2023.Snail abundance was significantly and positively correlated with pH(β=27.22,P<0.001),turbidity(β=1.117,P=0.008),and total nitrate(β=71.4,P=0.04),and negatively correlated with conductivity,temperature,total dissolved solids,salinity,and dissolved oxygen.No S.mansoni infections were detected;however,69.95%of snails were infected with echinostome cercariae.B.pfeifferi was the dominant species.Sequence analysis revealed genetic diversity,with five NCBI reference sequences forming a distinct clade from the study samples.Conclusions:B.pfeifferi populations showed seasonal variation and strong environmental associations,emphasizing the need for ecological monitoring in schistosomiasis control.展开更多
The System of Rice Intensification (SRI) has been attributed to improvement in rice production with various attributes being accrued from application of the SRI Principles. The most notable are savings on water use an...The System of Rice Intensification (SRI) has been attributed to improvement in rice production with various attributes being accrued from application of the SRI Principles. The most notable are savings on water use and increase in yield. Alternate Wetting and Drying (AWD) has also paved way for mechanical weed control in paddy fields. One of the major constraints to adoption of SRI is the perceived increased labour input due to the careful transplanting and frequent weed control. This paper evaluates the effect of mechanization on labour input in SRI in comparison to the less mechanized farmer practice. In attempt to reduce drudgery in transplanting under SRI, the drum seeder was used to establish the rice crop by direct seeding. This was then followed by using SRI practices i.e. AWD and mechanical weeding. Direct seeding using a drum seeder was compared to transplanting in both SRI and the common farmer practice. Hand weeding was also evaluated and compared to mechanical weeding. Labour input cost was also compared to the income accrued from the yields. From the study, it was noted that direct seeding using the drum seeder reduced labour input by 97% compared to transplanting. This was possible in that in direct seeding, and there was no nursery preparation and management as in transplanting. The use of a mechanical weeder reduced labour input by 28.3% in relation to hand weeding. Labour input cost for SRI was cheaper (Kshs. 124,080 per hectare) compared to the common farmer practice (Kshs. 139,117.50 per hectare). There was more yield from the SRI practice (2.75 Ton/ha) compared to the common farmer practice (1.88 Ton/ha).展开更多
文摘Objective:To study the distribution and abundance of Biomphalaria(B.)pfeifferi species in the Mwea Irrigation Scheme,their role as intermediate hosts for Schistosoma(S.)mansoni,and the impact of water parameters.Methods:A longitudinal field survey was conducted across eight administrative wards and five habitat types using a time-based metal scoop method.Physicochemical water quality parameters were measured both in situ and in the laboratory.The snails were examined for S.mansoni infections by shedding method,and cercariae were identified microscopically.Species identification was also performed.The data was analyzed using ANOVA,regression analysis,and Pearson correlation to identify the association between water physiochemical parameters and Biomphalaria snail abundance.Level of significance was determined at 5%(P≤0.05)with 95%confidence limit.Results:A total of 2013 Biomphalaria species were collected,mainly from Murinduko and Nyangati Wards.Streams(965,47.93%)and tertiary canals(676,33.58%)showed the highest abundance.Biomphalaria species populations were recorded in September 2022(1225),with declines noted in February and August 2023.Snail abundance was significantly and positively correlated with pH(β=27.22,P<0.001),turbidity(β=1.117,P=0.008),and total nitrate(β=71.4,P=0.04),and negatively correlated with conductivity,temperature,total dissolved solids,salinity,and dissolved oxygen.No S.mansoni infections were detected;however,69.95%of snails were infected with echinostome cercariae.B.pfeifferi was the dominant species.Sequence analysis revealed genetic diversity,with five NCBI reference sequences forming a distinct clade from the study samples.Conclusions:B.pfeifferi populations showed seasonal variation and strong environmental associations,emphasizing the need for ecological monitoring in schistosomiasis control.
文摘The System of Rice Intensification (SRI) has been attributed to improvement in rice production with various attributes being accrued from application of the SRI Principles. The most notable are savings on water use and increase in yield. Alternate Wetting and Drying (AWD) has also paved way for mechanical weed control in paddy fields. One of the major constraints to adoption of SRI is the perceived increased labour input due to the careful transplanting and frequent weed control. This paper evaluates the effect of mechanization on labour input in SRI in comparison to the less mechanized farmer practice. In attempt to reduce drudgery in transplanting under SRI, the drum seeder was used to establish the rice crop by direct seeding. This was then followed by using SRI practices i.e. AWD and mechanical weeding. Direct seeding using a drum seeder was compared to transplanting in both SRI and the common farmer practice. Hand weeding was also evaluated and compared to mechanical weeding. Labour input cost was also compared to the income accrued from the yields. From the study, it was noted that direct seeding using the drum seeder reduced labour input by 97% compared to transplanting. This was possible in that in direct seeding, and there was no nursery preparation and management as in transplanting. The use of a mechanical weeder reduced labour input by 28.3% in relation to hand weeding. Labour input cost for SRI was cheaper (Kshs. 124,080 per hectare) compared to the common farmer practice (Kshs. 139,117.50 per hectare). There was more yield from the SRI practice (2.75 Ton/ha) compared to the common farmer practice (1.88 Ton/ha).
