Incubation of Spirometra eggs at laboratory conditions by Modified Harada-Mori method

Incubation of Spirometra eggs was conducted in the helminthology laboratory Faculty of Veterinary Medicine, Sokoine University of Agriculture during the period July to September, 2012. Spirometra eggs from faeces of naturally infected lions (Panthera leo) from Tarangire National Park, Tanzania were cultured at laboratory condition using modified Harada-Mori method. The objective of the study was to hatch coracidia and use in a life-cycle experiment. The culture consisted of a thin film of washed eggs on a strip of filter paper inserted in an upright falcon tubes containing sterile sand and stones to the bottom up to 1 cm level and aquarium water up to just below the egg smear. Eggs were cultured at temperature 26-29ºC and light. On day 6 the eggs started hatching coracidia. Under the circumstance it was fruitful to culture Spirometra eggs using modified Harada-Mori method. The modified Harada-Mori culture technology showed a high rate of hatching of Spirometra eggs. We recommend using this modified Harada-Mori method for culture of Spirometra eggs being able to hatch many eggs, inexpensive and less time consuming.Key words: Harada-Mori, culture, eggs, Spirometra

Redefining the "carrier" state for foot-and-mouth disease from the dynamics of virus persistence in endemically affected cattle populations

The foot-and-mouth disease virus (FMDV) “carrier” state was defined by van Bekkum in 1959. It was based on the recovery of infectious virus 28 days or more post infection and has been a useful construct for experimental studies. Using historic data from 1,107 cattle, collected as part of a population based study of endemic FMD in 2000, we developed a mixed effects logistic regression model to predict the probability of recovering viable FMDV by probang and culture, conditional on the animal’s age and time since last reported outbreak. We constructed a second set of models to predict the probability of an animal being probang positive given its antibody response in three common non-structural protein (NSP) ELISAs and its age. We argue that, in natural ecological settings, the current definition of a ”carrier” fails to capture the dynamics of either persistence of the virus (as measured by recovery using probangs) or the uncertainty in transmission from such animals that the term implies. In these respects it is not particularly useful. We therefore propose the first predictive statistical models for identifying persistently infected cattle in an endemic setting that captures some of the dynamics of the probability of persistence. Furthermore, we provide a set of predictive tools to use alongside NSP ELISAs to help target persistently infected cattle