Daily Archives: July 15, 2014

Cats more likely cause of Toxoplasma exposure than well water

This study has a serious confounding limitation — accidentally swallowing T. gondii through contact with cat feces that contain Toxoplasma. This might happen by 1. cleaning a cat’s litter box when the cat has shed Toxoplasma in its feces, 2. touching or ingesting anything that has come into contact with cat feces that contain Toxoplasma, 3. accidentally ingesting contaminated soil (e.g., not washing hands after gardening or eating unwashed fruits or vegetables from a garden). click here for more.

Does NHANES have a metadata field for “Cat present/not present in the home?”. If not, then I’d say cat-associated exposures are more likely than well water to be the cause of endemic levels of Toxoplasma.

Krueger WS, Hilborn ED, Converse RR, Wade TJ. BMC Public Health. 2014 Jul 10;14(1):711. Drinking water source and human Toxoplasma gondii infection in the United States: a cross-sectional analysis of NHANES data.

BACKGROUND: Toxoplasma gondii imparts a considerable burden to public health. Human toxoplasmosis can be life-threatening in immunocompromised individuals, has been associated with psychiatric disorders, and can cause severe congenital pathologies, spontaneous abortion, or stillbirth. Environmental modes of transmission contributing to the incidence of human toxoplasmosis are poorly understood. We sought to examine National Health and Nutrition Examination Survey (NHANES) data for risk factors associated with T. gondii seroprevalence.

METHODS: T. gondii serology results reported for Continuous NHANES survey years 1999-2004 and 2009-10 were examined. To explore associations with toxoplasmosis seropositivity, covariates of interest were selected a priori, including source and home treatment of tap water. Associations between potential risk factors and evidence of IgG antibodies against T. gondii were assessed using multivariable logistic regression.

RESULTS: Among 23,030 participants with available T. gondii serology across 8 years of continuous NHANES survey data (1999-2004; 2009-2010), persons born outside the United States were significantly more likely to be seropositive, and seropositivity was inversely associated with years spent in the United States. Among US-born participants, participants with homes on well water (both those who used at-home water treatment devices and those who did not), as well as participants with public/private company-provided tap water who did not use at-home water treatment devices, were significantly more likely to be seropositive compared to participants who used home treatment devices on tap water provided by a private or public water company. A comparative subpopulation analysis revealed age-adjusted seroprevalence among US-born persons 12-49 yrs old significantly declined to 6.6% (95% CI, 5.2-8.0) (P < 0.0001) in 2009-10, compared to previously published reports for NHANES data from 1988-1994 (14.1%) and 1999-2004 (9.0%). 

CONCLUSIONS: Data suggests that T. gondii infections continue to decline in the United States, but the overall infection rate remains substantial at nearly 7%. Despite the limitations in the Continuous NHANES cross-sectional survey, the association between well water use and T. gondii infection warrants further research.

Click here for full paper (Open Source).

An example of the absence of competent historical scholarship on climate

Saying so does not make it so, even for professors. Climate did exist and forest fires did occur prior to the birth of all academics alive today. Without some basis in competent historical scholarship this statement is nothing more than a “religiously-held” opinion.

“Climate change is responsible for more frequent and larger forest fires, such as the ones now plaguing the Northwest Territories, says an Edmonton professor.” click here

Dr. Michael Mann slap down?

Regardless of what happened in this dispute, the idea that government funded research on any scientific topic can be done in complete secret without full disclosure of data and key communications is a travesty. Fairness and accountability of public monies (as well as the advancement of the sciences) are only possible if records and data are open to public disclosure and scrutiny (other than legitimate national security breaches). Keep in mind the requirement for “open records” cuts every which way regardless of a researcher’s perspective on climate change, global warming, or any other issue. Public accountability is absolutely necessary if there is public funding of research. 

“In a clear slap in the face, the Virginia Supreme Court awarded Michael E. Mann and the University of Virginia a piddling $250 in damages in the email FOIA case. Showing the triviality of the manner, the court’s order (shown here) didn’t even specify the rationale for the derisory amount. “ click here for the full article. 

Disinfection byproduct formation from lignin precursors

Hua G, Kim J, Reckhow DA. Disinfection byproduct formation from lignin precursors. Water Res. 2014 Jul 1;63C:285-295. doi: 10.1016/j.watres.2014.06.029.

Lignin is the most abundant aromatic plant component in terrestrial ecosystems. This study was conducted to determine the contribution of lignin residues in natural water to the formation of disinfection byproducts (DBPs) in drinking water. We investigated the formation of different classes of DBPs from lignin model compounds, lignin polymers, and humic substances using two common disinfection techniques, chlorination and chloramination. The contributions of lignin to the overall formation of DBPs from these organic products were determined based on the observed abundances of individual lignin phenols and their DBP yields. Model lignin phenols generally produced higher trichloroacetic acid (TCAA) yields than chloroform and dichloroacetic acid (DCAA) during chlorination. Lignin phenols generally produced higher DBP yields but lower percentages of unknown total organic halogen compared to bulk humic substances and lignin polymers. The relative significance of lignin phenols as chlorination DBP precursors generally follows the order of TCAA > DCAA & chloroform. The relative significance of lignin phenols to DBP formation by chloramination follows the order: TCAA > DCAA & DCAN > chloroform. Overall, lignin phenols are more important as TCAA precursors than as chloroform and DCAA precursors.

Click here for full paper (fee).