2 resultados para FORCE OF INFECTION
em AMS Tesi di Dottorato - Alm@DL - Università di Bologna
Resumo:
Strongylosis in equids, despite being very common, have never been studied from a strictly ecological point of view. Mathematical models are important ecological tools used to study the temporal dynamics of parasite populations, and are useful to study the effect of different biological parameters, as well as to analyse the outcome produced by perturbations such as anthelmintic treatments. This work describes the study of the temporal dynamics of strongyles infection in an organic donkey population, performed using coprological quantitative analysis and donkeys’ age as a proxy of the time of infection. Force of infection was then estimated for Strongylus vulgaris and small strongyles and the results used as the basis for the development of mathematical models. In particular, the comparison of models output and field data made it possible to estimate the transmission coefficient and to consequently calculate the basic reproduction number R0 and the threshold host density. Small strongyles model includes hypobiosis and, more interestingly as never found in literature, a density-dependent development rate of hypobiotic larvae in adult parasites in order to simulate a negative feedback between larvae emergence from hypobiosis and adult parasite abundance. Simulations of pharmacological and environmental treatments showed that parasite eradication was possible for S. vulgaris only, while small strongyles, due to hypobiosis and density-dependent development rate of their hypobiotic larvae, are very difficult to control and impossible to eradicate. In addition, density-dependence in larval development has been demonstrated to act as a key factor in improving parasite population survival and abundance even in absence of human intervention.
Resumo:
Objective To find a correlation between cerebral symptoms at birth and abnormalities found at anomaly scan, through the analysis of sensitivity of the anomaly scan in the prediction of severe CMV neonatal disease. Methods - Design, Setting, Population This was a retrospective collection of all cases of primary congenital CMV infection reported in our unit (Obstetrics and Perinatal Medicine, Policlinico di S Orsola, IRCSS, Bologna) over a period of 9 years (2013–2022). Only cases of fetal infection following confirmed maternal primary infection in the first trimester (MPI) and newborns with confirmed CMV infection on blood/saliva or urine were included. Results Between 2014 and 2022, 69 fetuses had an antenatal diagnosis of primary CMV infection. The infection occurred after MPI in the first, second, and third trimester in 63.7% (43/69), 27.5% (19/69), and 10% (7/69) of cases, respectively. Second-trimester assessment by anomaly scan was abnormal in 10/69 (15%) fetuses: 5/69 (7%) had an extracerebral STA and 5/69 (7%) had a cerebral STA. Normal anomaly scan was found in 59/69 (86%) fetuses. When looking at all fetuses infected in the first trimester, 12.5% (5/40) underwent TOP and 45% (18/40) had symptoms at birth. A mean follow-up of 22.4 months (range 12–48 months) was available for 68/69 (99%) live born neonates. Conclusion Anomaly scan results to have a predictive positive value of 67% fetuses infected in the first trimester. Serial assessment by ultrasound is necessary to predict the risk of sequelae occurring in 35% following fetal infection in the first trimester of pregnancy. This combined evaluation by US and trimester of infection should be useful when counselling on the prognosis of cCMV infection.