The Savannah gerbil, Gerbilliscus gambianus (Muridae: Gerbillinae) is important to the ecological relations of the dry grassland ecosystem of West Africa, as well as, being a zoonotic agent of human diseases and potential crop pest. We examined the impact of seasonal changes on the population dynamics of G. gambianus in northern Nigeria, by completing population estimates using capture–mark–recapture (CMR) and indirect population density indices (PDI) methods. The latter included fecal pellet counts and limited spotlightening. During 1990–1992 we collected both CMR and PDI data, and established their relationship by regression, thus calibrating the PDI values to CMR estimator. We also completed a separate, PDI only, study during 2015–2017, and estimated monthly densities indirectly by toning the PDI values to population sizes in the CMR estimator. The lowest declines (<20 gerbils ha−1) were in mid rains (July–August), and highest increases (>90 gerbils ha−1) were after the rains (October–January). Seasonal effects on densities were significant during 1990–1992 but not during 2015–2017. There were improved survival rates for both adults (0.95) and young (0.83), adult capture probability (0.56), and mean monthly recruitment of young (23) after the rains. There was no significant change in the overall population dynamic pattern of G. gambianus over a 25-year period. Because G. gambianus did not maintain colonies inside farmlands cultivated by rain or irrigation, and its tendency for large population drops in mid-rains, we are in doubt of its potential as crop pest in northern Nigeria.
Aim/objective: Since 2007, companies in the EU must submit paediatric investigation plans (PIPs) for new drugs, unless the PIP is waived and the review article investigated if that improve the child healthcare. Methods: We analysed the EU Paediatric Regulation (EUPR), PIP decisions, PIP decision patterns, EU key documents on "better medicines for children" and examined PIP studies versus the epidemiology described in the reference literature. We examined how PIPs translate into studies by checking www. clinicaltrials.gov and www.clinicaltrialsregister.org. We also investigated the medical sense of PIP-demanded clinical studies in adolescents. Results: The EUPR in Art. 2 (1) defines “paediatric population” as those between birth and 18 years. It lists challenges in dosing and safety of drugs in neonates and infants as if these challenges apply to anybody < 18 years. PIPs demand studies in adolescents although this group needs separate dose finding and efficacy studies only in exceptional cases, if at all. Most PIP studies in rare diseases are unfeasible: too many studies for too few patients in general. Two questionable PIP studies were discontinued in 2016, in one of them several patients died. Conclusions: Neonates and infants have immature organs, with resulting potential for drug over/underdosing. PIPs equalize the legal definition of childhood with a biological limit. The resulting automatism leads to a worldwide threat to children. Most PIP-demanded studies are medically senseless, some even worse. Ethics committees should reject questionable PIP studies and suspend such ongoing studies immediately.