No abstract

No abstract

Background: Evolutionary theory suggests that the selection pressure on parasites to maximize their transmission determines their optimal host exploitation strategies and thus their virulence. Establishing the adaptive basis to parasite life history traits has important consequences for predicting parasite responses to public health interventions. In this study we examine the extent to which malaria parasites conform to the predicted adaptive trade-off between transmission and virulence, as defined by mortality. The majority of natural infections, however, result in sub-lethal virulent effects (e.g. anaemia) and are often composed of many strains. Both sub-lethal effects and pathogen population structure have been theoretically shown to have important consequences for virulence evolution. Thus, we additionally examine the relationship between anaemia and transmission in single and mixed clone infections.

This study was conducted to assess the repellent and adulticide efficacy of the combination containing 10% imidacloprid and 50% permethrin against Aedes aegypti mosquitoes on dogs. Blood-feeding success rates of the mosquitoes that were exposed to the treated dogs were 4.9 and 4.4% on days 3 and 7 post the combination application (PCA), respectively, and blood-feeding success rates increased to 6.3, 12.8, and 24.5% on days 14, 21, and 28 PCA, respectively. Blood-feeding success rates between the mosquitoes that were exposed to the treated and untreated control dogs on days 3, 7, 14, and 21 PCA were significantly different. All mosquitoes that were exposed to the treated dogs on day 3 PCA died, and mortality rates decreased to 97.1, 77.8, 40.4, and 2.1% on days 7, 14, 21, and 28 PCA, respectively. Mortality rates between the mosquitoes that were exposed to the treated and untreated control dogs on days 3, 7, 14, and 21 PCA were significantly different. This study suggested that this combination can be used to repel and kill mosquitoes on dogs; however, the application of this insecticide combination on dogs needs to be repeated every 3-4 weeks.

The efficacy of 5 antimalarial drugs was evaluated on P. gallinaceum infected broilers. One hundred and forty-seven 19-day-old broilers were divided into 7 groups of 21 chicks each. Group 1 was the unmedicated, uninfected control. Groups 2–6 were infected and medicated with artesunate, chloroquine, doxycycline, primaquine and an artesunate-primaquine combination, respectively. Group 7 was the unmedicated, infected control. Infectivity, mortality, parasitemia, schizonts in tissues and body weight gain were monitored. The results revealed that the two most effective drugs for treating P. gallinaceum at the asexual erythrocyte stage were chloroquine and doxycycline. Tissue schizonts of P. gallinaceum in all the medicated groups were significantly fewer than the unmedicated, infected control (P<0.05). The mortality rate of all the medicated groups was significantly lower than the unmedicated, infected control (P<0.05).