Impact of the crayfish Procambarus clarkii on Schistosoma haematobium transmission in Kenya.
نویسندگان
چکیده
The Louisiana red swamp crayfish, Procambarus clarkii, which was introduced into east Africa in the 1950s or 1960s, has since widely dispersed. Previous work by our group has shown that P. clarkii can reduce populations of the molluscan intermediate hosts of human schistosomes through predatory and competitive interactions. Here, we investigate whether crayfish can reduce populations of Bulinus africanus and consequently, Schistosoma haematobium prevalence in school children. Children from 6 primary schools in the Machakos and Kitui Districts of Kenya were selected for study. Schools were divided into 3 experimental-control pairs. At experimental schools, crayfish were introduced into nearby aquatic habitats harboring Bulinus africanus snails and serving as S. haematobium transmission sites. Snail habitats near control schools did not receive crayfish. Six months after crayfish introduction, all infected children were treated with praziquantel. Children were then monitored quarterly for 2 years, at which time infection and reinfection rates were compared statistically between the paired schools. In one such pair, crayfish failed to establish, resulting in neither snail control nor a reduction in transmission. At the second pair of schools, the numbers of snails were decreased by the presence of crayfish, but a clear difference in infection rates in children could not be detected, primarily because drought conditions kept overall transmission rates low. At the third school pair, crayfish established well in experimental habitats, snail numbers decreased precipitously, and children at the experimental school were significantly less likely to acquire S. haematobium infections than children at the control school. Our results indicate that under certain environmental circumstances, P. clarkii exerts a significant impact on the transmission of human schistosomiasis in Kenya. Important questions remain regarding the impact of P. clarkii on Kenyan freshwater ecosystems, not the least of which is its potential to significantly influence the epidemiology of schistosomiasis in east Africa.
منابع مشابه
Aeromonas hydrophila, one reason causing the death of freshwater crayfish Procambarus clarkii (Girard, 1852)
Procambarus clarkii crayfish has been developed as an excellent animal model to study the characteristics and pathogenesis of white spot syndrome virus and the host defense mechanisms of crustacean. However, due to pathogen infections of crayfish in Chinese farms, research based on this model has been slowed down. Using triplex polymerase chain reaction, we found the virulence Aeromonas hydroph...
متن کاملOnion powder as feed additive in Procambarus clarkii culture
120 days trial was performed to evaluate the effect of dietary onion powder on the growth performance of red swamp crayfish Procambarus clarkii. Crayfish with initial body weight of 1.37±0.13 g were randomly stocked to experimental tanks. Four different onion powder levels in ratios of 10, 20, 30, and 40 g/kg were added to the formulated experimental basal feed and a control group was fed with ...
متن کاملEffect of starvation on growth, histology and ultrastructure of digestive system of juvenile red swamp crayfish (Procambarus clarkii Girard)
The present study was conducted to evaluate the effect of 20 d starvation on growth, survival, histomorphology and ultrastructure changes in the digestive system of juvenile red swamp crayfish (Procambarus clarkii). Juveniles were divided into two groups: a food-deprived group and a control group at 9 day after hatch (DAH). Individuals were sampled at 14, 20, 29 DAH. During the 20 d fasting per...
متن کاملCan the freshwater crayfish eradicate schistosomiasis in Egypt and Africa?
Schistosomiasis is a chronic, parasitic disease, infecting more than 207 million people, mostly from Africa, with an estimated 700 million people at risk in 74 endemic countries. One of strategies to eradicate this disease is biocontrol of its vector snail. Lab experiments and field survey have been carried out to investigate the impact and the relationship between the exotic crayfish; Procamba...
متن کاملEffect of starvation on growth, histology and ultrastructure of digestive system of juvenile red swamp crayfish (Procambarus clarkii Girard)
The present study was conducted to evaluate the effect of 20 d starvation on growth, survival, histomorphology and ultrastructure changes in the digestive system of juvenile red swamp crayfish (Procambarus clarkii). Juveniles were divided into two groups: a food-deprived group and a control group at 9 day after hatch (DAH). Individuals were sampled at 14, 20, 29 DAH. During the 20 d fasting per...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- The American journal of tropical medicine and hygiene
دوره 61 5 شماره
صفحات -
تاریخ انتشار 1999