Abstract:
Schistosomiasis is a disease of grave concern through out the world because of its high morbidity and mortality rates. Success of treatment usually depends on the extent of damage already caused by the infection at the time of diagnosis. There is therefore great need for studies that may aid in the early diagnosis of the disease, before irreversible damage has already occurred, and in the effective management of treatment. During the acute phase response, which takes place at the very beginning of the inflammatory process, there are changes in concentrations of a large number of serum proteins and cations. These changes are attributed to the host response to tissue injury and are therefore useful indicators for the course and severity of a disease. In this Study, sequential serum specimens from baboon and mouse models infected with S. mansoni were collected throughout the course of acute infection and following treatment with praziquantel, a drug curative for Schistosoma mansoni. Sampling was also done in baboon models following post-treatment challenge by a second infection. In these specimens, haptoglobin was measured by ELISA, while albumin and the cations (iron, zinc and copper) were measured spectrophotometrically. In addition, the acute histopathology of the infected mouse models was studied for any correlations with changes in the serum proteins and cations. The results of the study showed that both mice and baboon models develop a similar acute phase response following infection with S. mansoni cercariae. In both models, there was an increase in haptoglobin and copper concentrations; and a decrease in albmnin, iron and zinc concentrations following infection. Haptoglobin appeared to be the better indicator of early infection and residual tissue pathology. Similar changes, though notably less pronounced, were observed in the baboons that were challenged. The post-infection changes were seen to recover following curative treatment. This correlated well with reducing tissue damage and inflammation evidenced in the histopathological studies of treated mice. The findings of this study have enhanced the understanding of the acute phase response, with particular focus on the diagnostic and prognostic potential of haptoglobin, albumin and the serum cations, in S. mansoni infection. Further detailed studies involving a greater population of primate models, more frequent sampling times and a wider variety of analytes would be useful in validating such assays for use in human medicine.
