Vaccines against toxoplasma gondii : challenges and opportunities

Development of vaccines against Toxoplasma gondii infection in humans is of high priority, given the high burden of disease in some areas of the world like South America, and the lack of effective drugs with few adverse effects. Rodent models have been used in research on vaccines against T. gondii over the past decades. However, regardless of the vaccine construct, the vaccines have not been able to induce protective immunity when the organism is challenged with T. gondii, either directly or via a vector. Only a few live, attenuated T. gondii strains used for immunization have been able to confer protective immunity, which is measured by a lack of tissue cysts after challenge. Furthermore, challenge with low virulence strains, especially strains with genotype II, will probably be insufficient to provide protection against the more virulent T. gondii strains, such as those with genotypes I or II, or those genotypes from South America not belonging to genotype I, II or III. Future studies should use animal models besides rodents, and challenges should be performed with at least one genotype II T. gondii and one of the more virulent genotypes. Endpoints like maternal-foetal transmission and prevention of eye disease are important in addition to the traditional endpoint of survival or reduction in numbers of brain cysts after challenge

Pioneering figures in medicine: Albert Bruce Sabin - inventor of the oral polio vaccine

Over ten years after his death, the Sabin oral vaccine continues its profound influence on public health throughout the world. The annual incidence of polio has fallen dramatically since its introduction, with more than 300,000 lives being spared each year and an annual global saving in excess of 1 billion US dollars. In many ways, the development of an effective oral vaccine and its subsequent regulation by the World Health Organization can serve as a model for medical researchers. Our review describes the contribution of Albert Sabin as a medical researcher, and how his vaccine had a profound impact on the global reduction of polio infections. As many different factors influenced health-care last century, we describe Sabin's involvement with respect to prevailing scientific paradigms and public health issues of the time. Our paper also outlines the basic epidemiology of poliovirus and the historical development of an effective vaccine, both with and without Albert Sabin

Bat-Associated Leptospirosis

Leptospirosis is a globally prevalent disease that affects humans, causing systemic illness that may lead to multi-organ involvement. Clinical signs include sudden fever, general malaise, muscular pain, conjunctival suffusion, and jaundice. Disease is caused by pathogenic bacteria including over 200 serologic variants. Most serologic variants have primary reservoirs in wild mammals, which continually infect and colonize domesticated animals. The organism has been recovered from rats, swine, dogs, cattle, and other animals, notably bats. Most studies have focused on domestic animals as reservoir hosts; however, because of their abundance, spatial distribution, and interrelationship with domestic animals, bats are becoming an epidemiologically significant source of leptospires. We present a case of serologically confirmed leptospirosis after bat exposure to add to the growing literature of bats as a possible source of transmission. Recognition of the common presentation of leptospirosis and Weil’s disease, and identification of animal vectors, including bats, allows for the selection of appropriate antibiotic management to aid in resolution of symptomotology

Assessment of the ecotoxicological risk of combined sewer overflows for an aquatic system using a coupled “substance and bioassay” approach

International audienceVery few tools are available for assessing the im- pact of combined sewer overflows (CSOs) on receiving aquat- ic environments. The main goal of the study was to assess the ecotoxicological risk of CSOs for a surface aquatic ecosystem using a coupled “substance and bioassay” approach. Wastewater samples from the city of Longueuil, Canada CSO were collected for various rainfall events during one summer season and analyzed for a large panel of substances (n = 116).Fourbioassayswerealsoconductedonrepresenta- tive organisms of surface aquatic systems (Pimephales promelas, Ceriodaphnia dubia, Daphnia magna, and Oncorhynchus mykiss). The analytical data did not reveal any ecotoxicological risk for St. Lawrence River organisms, mainly due to strong effluent dilution. However, the substance approach showed that, because of their contribution to the ecotoxicological hazard posed by the effluent, total phospho- rus (Ptot), aluminum (Al), total residual chlorine, chromium (Cr), copper (Cu), pyrene, ammonia (N–NH4+), lead (Pb), and zinc (Zn) require more targeted monitoring. While chronic ecotoxicity tests revealed a potential impact of CSO dis- charges on P. promelas and C. dubia, acute toxicity tests did not show any effect on D. magna or O. mykiss, thus underscoring the importance of chronic toxicity tests as part of efforts aimed at characterizing effluent toxicity. Ultimately, the study leads to the conclusion that the coupled “substance and bioassay” approach is a reliable and robust method for assessing the ecotoxicological risk associated with complex discharges such as CSOs