Baculovirus entry into the central nervous system of Spodoptera exigua caterpillars is independent of the viral protein tyrosine phosphatase.

Neuroparasitism concerns the hostile take-over of a host's nervous system by a foreign invader, in order to alter the behaviour of the host in favour of the parasite. One of the most remarkable cases of parasite-induced host behavioural manipulation comprises the changes baculoviruses induce in their caterpillar hosts. Baculoviruses may manipulate caterpillar behaviour in two ways: hyperactivity (increased movement in the horizontal plane) and/or tree-top disease (movement to elevated levels in the vertical plane). Those behavioural changes are followed by liquefaction and death of the caterpillar. In Autographa californica multiple nucleopolyhedrovirus (AcMNPV)-infected Spodoptera exigua caterpillars, an enzymatic active form of the virally encoded protein tyrosine phosphatase (PTP) is needed for the expression of hyperactivity from 3 days post infection (dpi). Using eGFP-expressing recombinant AcMNPV strains, we show that infection of the caterpillar's central nervous system (CNS) can be observed primarily from 3 dpi onwards. In addition, we demonstrate that the structural and enzymatic function of PTP does not play a role in infection of the CNS. Instead we show that the virus entered the CNS via the trachea, progressing caudally to frontally through the CNS and that the infection progressed from the outermost cell layers towards the inner cell layers of the CNS, in a PTP independent manner. These findings help to further understand parasitic manipulation and the mechanisms by which neuroparasites infect the host nervous system to manipulate host behaviour.

YouTube: are parent-uploaded videos of their unwell children a useful source of medical information for other parents?

AIMS: YouTube is a vast source of freely accessible user-uploaded medical information. To our knowledge no study has analysed the quality of parent-uploaded videos which depict illness in their children. We aimed to investigate the quality and quantity of videos representing two common conditions, croup and dehydration. METHOD: YouTube was searched using the search terms 'croup+child' and 'dehydration+child'. The first 400 videos of each search were screened. Videos created by doctors or by educational institutions were excluded. The parent-uploaded videos were analysed using the validated Medical Video Rating Scale. Each video was separately evaluated for whether it represented a good clinical example of the condition featured. RESULTS: Out of 38 'croup' videos which met criteria, 15 were judged to be good clinical examples. Only 7 of these 15 'good clinical example' videos were also of high technical quality. Out of 28 'dehydration' videos which met the inclusion criteria, two were good clinical examples. One of these videos had good technical quality. CONCLUSIONS: There were very few videos of either condition which showed a good clinical example while also displaying high technical quality. It is extremely difficult and time consuming to isolate such examples from the mass of information available and therefore parents could be misled by apparently high technical quality videos which are not in fact good clinical examples. Healthcare professionals should be careful when discussing finding medical information on YouTube and consider creating repositories of good examples so they are able to direct parents towards more reputable resources.