Daily Archives: March 1, 2016

Immune System Effects of Strontium-90

Synhaeve N, Musilli S, Stefani J, Nicolas N, Delissen O, Dublineau I, Bertho JM. Immune System Modifications Induced in a Mouse Model of Chronic Exposure to 90Sr. Radiation research. 2016 Mar 1.

Strontium 90 (90Sr) remains in the environment long after a major nuclear disaster occurs. As a result, populations living on contaminated land are potentially exposed to daily ingesting of low quantities of 90Sr. The potential long-term health effects of such chronic contamination are unknown. In this study, we used a mouse model to evaluate the effects of 90Sr ingestion on the immune system, the animals were chronically exposed to 90Sr indrinking water at a concentration of 20 kBq/l-1, for a daily ingestion of 80-100 Bq/day-1. This resulted in a reduced number of CD19+ B lymphocytes in the bone marrow and spleen in steady-state conditions. In contrast, the results from a vaccine experiment performed as a functional test of the immune system showed that in response to T-dependent antigens, there was a reduction in IgG specific to tetanus toxin (TT), a balanced Th1/Th2 response inducer antigen, but not to keyhole limpet hemocyanin (KLH), a strong Th2 response inducer antigen. This was accompanied by a reduction in Th1 cells in the spleen, consistent with the observed reduction in specific IgG concentration. The precise mechanisms by which 90Sr acts on the immune system remain to be elucidated. However, our results suggest that 90Sr ingestion may be responsible for some of the reported effects of internal contamination on the immune system in civilian populations exposed to the Chernobyl fallout.

Distance to Water Source and Diarrhea, Kenya

Nygren BL, O’Reilly CE, Rajasingham A, Omore R, Ombok M, Awuor AO, Jaron P, Moke F, Vulule J, Laserson K, Farag TH, Nasrin D, Nataro JP, Kotloff KL, Levine MM, Derado G, Ayers TL, Lash RR, Breiman RF, Mintz ED. The Relationship Between Distance to Water Source and Moderate-to-Severe Diarrhea in the Global Enterics Multi-Center Study in Kenya, 2008-2011. The American Journal of Tropical Medicine and Hygiene. Am J Trop Med Hyg. 2016 Feb 29. pii: 15-0393.

In the developing world, fetching water for drinking and other household uses is a substantial burden that affects water quantity and quality in the household. We used logistic regression to examine whether reported household water fetching times were a risk factor for moderate-to-severe diarrhea (MSD) using case-control data of 3,359 households from the Global Enterics Multi-Center Study in Kenya in 2009-2011. We collected additional global positioning system (GPS) data for a subset of 254 randomly selected households and compared GPS-based straight line and actual travel path distances to fetching times reported by respondents. GPS-based data were highly correlated with respondent-provided times (Spearman correlation coefficient = 0.81, P < 0.0001). The median estimated one-way distance to water source was 200 m for cases and 171 for controls (Wilcoxon rank sums/Mann-Whitney P = 0.21). A round-trip fetching time of > 30 minutes was reported by 25% of cases versus 15% of controls and was significantly associated with MSD where rainwater was not used in the last 2 weeks (odds ratio = 1.97, 95% confidence interval = 1.56-2.49). These data support the United Nations definition of access to an improved water source being within 30 minutes total round-trip travel time.