Biological control of three floating water weeds, Eichhornia crassipes, Pistia stratiotes, and Salvinia molesta in the Republic of Congo

Since 1999, four specific weevils (Coleoptera, Curculionidae) were released in the Republic of Congo against three exotic floating water weeds: Neochetina eichhorniae Warner and N. bruchi Hustache against water hyacinth, Neohydronomus affinis Hustache against water lettuce, and Cyrtobagous salviniae Calder and Sands against water fern. Recoveries of exotic weevils were made from all 24 release sites except one, and all four species have established and spread (up to 800 km for water hyacinth weevils). Within a few years of releases, control of water fern and water lettuce was such that fishing and navigation could be resumed, while reductions of water hyacinth populations were only beginning

Impact of waste disposal on health of a poor urban community in Zimbambwe

Objective: To assess excreta and waste disposal facilities available and their impact on sanitation related diseases in Epworth, an informal settlement on the outskirts of Harare. Design: Descriptive cross-sectional survey. Setting: This was a community based study of Epworth informal settlement. Subjects: A total of 308 households were interviewed. Participating households were randomly selected from the three communities of Epworth. Secondary medical archival data on diarrhoeal disease prevalence was collected from local clinics and district health offices in the study areas. Results: Only 7% of households were connected to the sewer system. The study revealed that in Zinyengere extension 13% had no toilet facilities, 48% had simple pits and 37% had Blair VIP latrines. In Overspill 2% had no toilet facilities, 28% had simple latrines and 36% had Blair VIP latrines while in New Gada 20% had no toilet facilities, 24% had simple pits and 23% had Blair VIP latrines. Although a significant percentage had latrines (83.2%), over 50% of the population were not satisfied with the toilet facilities they were using. All the respondents expressed dissatisfaction with their domestic waste disposal practices with 46.6% admitting to have indiscriminately dumped waste. According to the community, diarrhoeal diseases were the most prevalent diseases (50%) related to poor sanitation. Health statistics also indicated that diarrhoea was a major problem in this community. Conclusion: It is recommended that households and the local authorities concentrate on improving the provision of toilets, water and waste disposal facilities as a way of improving the health state of the community. East African Medical Journal Vol.81(8) 2004: 422-42

Cutaneous hypersensitivity induced in rabbits by extracts of the tick Amblyomma cajennense (Acari : Ixodidae)

The cutaneous hypersensitivity test was used to correlate host resistance to ticks and type of reactions elicited by Amblyomma cajennense (Fabricius, 1787) tick extract in rabbits. Rabbits were divided into 3 groups of 2 animals each: naive, pre-infested and control. Cutaneous hypersensitivity was induced by intradermal inoculation of 25 mug extract in 0.03 rut of phosphate buffered saline (PBS) in rabbit ears. Control rabbits were inoculated with PBS only. The ear thickness was measured with a Mitutoyo(R) device before and 10 min, 1, 2,4,18, 24,48,72 and 96 h post-inoculation (PI). Pre-infested rabbits showed an immediate type reaction within the 1st 10 min PI (60 % increase in ear thickness) and a delayed reaction (18 h) (85 % increase), whereas the naive rabbits showed only the immediate reaction within the 1st 4 h (60 % increase). PBS induced only mild reactions. These results point out the crucial role of the cellular immune response of rabbits in the expression of resistance to A. cajennense

Importance of ticks and their chemical and immunological control in livestock

The medical and economic importance of ticks has long been recognized due to their ability to transmit diseases to humans and animals. Ticks cause great economic losses to livestock, and adversely affect livestock hosts in several ways. Loss of blood is a direct effect of ticks acting as potential vector for haemo-protozoa and helminth parasites. Blood sucking by large numbers of ticks causes reduction in live weight and anemia among domestic animals, while their bites also reduce the quality of hides. However, major losses caused by ticks are due to their ability to transmit protozoan, rickettsial and viral diseases of livestock, which are of great economic importance world-wide. There are quite a few methods for controlling ticks, but every method has certain shortcomings. The present review is focused on ticks importance and their control