A comparative study of Multiple versus Single infection doses of Schistosoma haematobium in Golden hamsters ( Mesocricetus auratus )

Schistosoma haematobium is widely distributed in Africa. In Kenya, endemic areas include the upper and the lower regions of the Coast Province, Lake Victoria and the Kano plains. Low infection rates over prolonged periods of time characterize schistosome infections of people living in endemic areas. However, the common laboratory practice is to expose the definitive host to a single high dose. In order to utilize the laboratory results appropriately, it is important to know whether or not a large single infection has similar results to multiple small doses. In this study, immune responses, worm burden, gross and histopathological patterns of multiple infection of S. haematobiumium in the Golden hamster ( Mesocricetus auratus ) were compared with those of single exposure. Multiple infections with low doses of the parasite did not seem to be protective, as suggested by; more worms, worse gross and histopathology in multiple low dose group compared to single high dose group. Most probably there is an antigenic threshold, which needs to be attained before protective mechanisms come into play. Although necessary for protection, there was no direct correlation between IgG levels and degree of protection

Influence of Age of Mice on the Susceptibility to Murine Schistosomiasis Infection

Intensity of human schistosomiasis infection increases with age, a peak being attained at early puberty. Hormones could be involved in the age-related changes in susceptibility to schistosomiasis. Male BALB/c mice were infected with Schistosoma mansoni either before or after puberty and worm numbers, cellular immune responses, hormonal levels and pathology analysed. Pre-puberty infected mice had a significantly higher number of adult worms (p<0.05), more severe granulomas, higher mortality rate and higher proliferative responses as compared to postpuberty infected mice. Levels of the hormones were lower in the pre-puberty infected mice as compared to the post-puberty group early in the infection. Plasma levels of testosterone and luteinizing hormones decreased significantly (p<0.05) in infected mice when compared to controls. Susceptibility to S. mansoni in male BALB/c mice seems to be influenced by levels of testosterone and leutenizing hormone at infection. Albeit, an infection with S. mansoni seems to lower the hormonal levels

A Comprehensive Genetic Analysis of Candidate Genes Regulating Response to Trypanosoma congolense Infection in Mice

About one-third of cattle in sub-Saharan Africa are at risk of contracting “Nagana”—a disease caused by Trypanosoma parasites similar to those that cause human “Sleeping Sickness.” Laboratory mice can also be infected by trypanosomes, and different mouse breeds show varying levels of susceptibility to infection, similar to what is seen between different breeds of cattle. Survival time after infection is controlled by the underlying genetics of the mouse breed, and previous studies have localised three genomic regions that regulate this trait. These three “Quantitative Trait Loci” (QTL), which have been called Tir1, Tir2 and Tir3 (for Trypanosoma Infection Response 1–3) are well defined, but nevertheless still contain over one thousand genes, any number of which may be influencing survival. This study has aimed to identify the specific differences associated with genes that are controlling mouse survival after T. congolense infection. We have applied a series of analyses to existing datasets, and combined them with novel sequencing, and other genetic data to create short lists of genes that share polymorphisms across susceptible mouse breeds, including two promising “candidate genes”: Pram1 at Tir1 and Cd244 at Tir3. These genes can now be tested to confirm their effect on response to trypanosome infection

A comparative study of Multiple versus Single infection doses of Schistosoma haematobium in Golden hamsters ( Mesocricetus auratus )

Schistosoma haematobium is widely distributed in Africa. In Kenya, endemic areas include the upper and the lower regions of the Coast Province, Lake Victoria and the Kano plains. Low infection rates over prolonged periods of time characterize schistosome infections of people living in endemic areas. However, the common laboratory practice is to expose the definitive host to a single high dose. In order to utilize the laboratory results appropriately, it is important to know whether or not a large single infection has similar results to multiple small doses. In this study, immune responses, worm burden, gross and histopathological patterns of multiple infection of S. haematobiumium in the Golden hamster ( Mesocricetus auratus ) were compared with those of single exposure. Multiple infections with low doses of the parasite did not seem to be protective, as suggested by; more worms, worse gross and histopathology in multiple low dose group compared to single high dose group. Most probably there is an antigenic threshold, which needs to be attained before protective mechanisms come into play. Although necessary for protection, there was no direct correlation between IgG levels and degree of protection